https://ascconline.org RSS feeds for American Society of Concrete Contractors 60 https://ascconline.org/Home/News/articleType/ArticleView/articleId/570/FFFL-Risks-Why-Testing-Methods-Matter-More-Than-Ever#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=570 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=570&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/570/FFFL-Risks-Why-Testing-Methods-Matter-More-Than-Ever Written By: Mike Hernandez, ASCC Technical Director  Few words strike fear in a concrete contractor’s heart like: “This floor doesn’t meet tolerance.” A failed floor flatness/levelness (FF/FL) report can trigger owner dissatisfaction, costly remediation or back charges, project delays, and in the worst cases, litigation. Yet what often gets lost in the dispute is whether the measurement itself is performed correctly by a qualified tester. Recent industry articles—along with an older Concrete International piece and the relevant ACI specifications and ASTM standards—highlight how significant testing practices and interpretation can influence, and even escalate, flatwork disputes. One focuses on common errors made when collecting data with walking floor profilers, another explores the capabilities and limits of laser scanning, the last looks at floor profiler operator qualifications. Taken together, they underscore one point: the credibility of tolerance measurements is critical to validate the reported FF/FL numbers. Importance of the FF/FL Test Report Concrete tolerances can have financial and even legal consequences. Owners and designers increasingly specify ACI 117 Floor Flatness (FF) and Floor Levelness (FL) values, as tested per ASTM E1155. If a testing agency reports a failing number, contractors are assumed at fault. But as Bill Arpin points out in “FF-FL Testing Mistakes: Understanding Concrete Floor Profiler Data Better”, that assumption can be misleading. Even small errors during data collection can swing results from a passing score to a failing one. A quarter inch misread can reduce FF and FL numbers in half, turning an acceptable slab into one deemed defective on paper. If the tests are performed more than 72 hours after placement or worse, after formwork is removed, these tests are not in compliance with the ACI 117 and ASTM E1155 standards and may be impacted by SOG curling or elevated slab deflection. Potential Errors from the Profiler Bill Arpin highlights three easy-to-spot mistakes that frequently plague walking profiler testing, (link to read the whole article is below in the References): Readings taken in the air – If the operator accidently takes a reading before the footpad contacts the surface, the graph will show a sharp vertical step. A single such error can drastically lower the FF/FL results. Stepping on debris or objects – A stray pebble, dust pile, or even something stuck to the footpad can create spikes in the data, again reducing the test. (Having felt this while pulling an F-meter I can attest that this happens easily in jobsite conditions.) Calibration issues – If one side of the profiler is miscalibrated or obstructed, a “sawtooth” pattern emerges. Even a 1/16-inch offset can knock a floor into failing territory. These aren’t hypothetical concerns. Bill provides graphs to show how introducing just one false reading can reduce an FF 65 floor to FF 28—well below most industrial floor requirements. For a contractor facing liquidated damages or repair costs, the distinction between recognizing data error vs actual defects is critical. Laser Scanning, Technology Solution or Part of the Problem? If floor profilers are prone to operator error, could 3D laser scanners solve the problem? An interlaboratory study published in Concrete International in Jan 2025 explored this question. Co-authored by Leo Zhang, Hernandez, Dare, Kowalski, and Che, the study examined the precision of terrestrial laser scanning (TLS) for verifying concrete tolerances. Thirteen participants, many of them ASCC Members, including contractors, surveyors, and manufacturers, scanned a post-tensioned slab and vertical elements on a Conco project in Santa Cruz, CA. The study was partially funded by the ASCC Foundation. The findings were encouraging: repeatability and reproducibility errors were improved when compared to the ASCC 2018 laser scanning study. This showed that TLS is maturing into a reliable tool for construction quality control. It concluded that tolerances greater than ½” can be determined using laser scanning. Still, the article cautions against assuming laser scans are infallible. Post-processing techniques like smoothing, meshing, or “best-fit” algorithms can introduce their own distortions. Human interpretation remains part of the workflow, and errors in point cloud analysis can misrepresent actual slab performance. Based on the capability to only confirm tolerances > than ½” laser scanners are not suitable for testing the FF/FL of a slab. Is this Operator Qualified to Test F-Numbers? An issue that can easily be overlooked is the qualification of the individual who is running the floor profiler. As described in the June 2024 ACI “Concrete Q&A: Operator Qualifications for Determining F-Numbers” by Klinger, Suprenant and Salzano, the operator’s training might be an issue. Training and certification by the floor profiler equipment manufacturer is better than on the job training by a co-worker. The article states “The preconstruction conference specified in ACI 301-20, Section 1.6.1, would be the appropriate time for all stakeholders to confirm all personnel (contractors and inspectors) are properly trained and certified to perform the work.” Is there an issue with interpretation of a single test line? An older article from CI, July 2008, “Concrete Q&A: Rejecting Floors based on One Sample Measurement Line” focused on whether a single line could be interpreted as a failing “local minimum”. ASTM E1155 defines a Test Section as “7.2 Test Section—A test section shall consist of any subdivision of a test surface satisfying the following criteria: 7.2.1 No test section shall measure less than 8 ft on a side, nor comprise an area less than 320 sf. 7.2.2 No portion of the test surface shall be associated with more than one test section. 7.2.3 When testing a concrete floor, no test section boundary shall cross any construction joint.” Therefore, a single placement with its boundaries being the construction joints would be the largest test section. The minimum number of individual readings on lines > 10 ft is A/30 for placements larger than 1,600 sf. So, for a 12,000-sf placement the minimum number of readings is 400.  If the bays are 30’x30’ each bay can be tested with parallel & perpendicular lines or X shaped diagonals. This area would be 13-14 bays. If it is a sawcut slab on grade when testing begins the lines can only be up to 26’ long parallel and perpendicular. Say ~25’ each way or 40’ diagonals. In 13 bays, 16 parallel and perpendicular 25’ lines would be the ASTM minimum, 26 would be expected to cover all full bays, yielding 650 readings. Ten 40’ diagonal lines would be the minimum, skipping several bays. Twenty-six ~40’ lines would cover all bays and provide over 1,000 readings. In this example the minimum local area could be as small as ~900 sf and it would need to be 3/5th of the specified overall, unless a local minimum is already defined in the specification. No single line can define an area so no single line could be used to define a local minimum. Single placements, in this example 12,000 sf, can be used as a “local minimum” if the testing lab only provides the daily FF/FL numbers and does not provide every run with the layout to provide the detail of smaller areas.     So why do slab flatness disputes persist? Three recurring issues: Too much trust in reports – When an FF/FL report arrives few stakeholders question the raw data or methods behind it. This can give too much weight to flawed results. The training of the floor profiler operator is rarely questioned and even less often confirmed to have been provided by the equipment manufacturer. Specification ambiguity – Project documents might not clearly define acceptable test methods, testing time limits, minimum local areas and acceptable methods. This leaves room for inappropriate tools, such as the use of a 10’ straightedge or a laser scanner to check FF/FL compliance. Technology gap – Contractors are usually more familiar with placing and finishing challenges than the statistical quirks of tolerance measurement. Testing agencies, meanwhile, may not recognize errors in their own reports. Avoiding the Dispute – Plan, Test and use the Data Appropriately What can ASCC contractors, owners, designers and testing labs do to reduce the risk of disputes? Confirm the plan before construction – ACI 301-20 addresses a preconstruction conference in section 1.6.1 with the contractor(s), design team, owner and owner’s representatives, such as a testing agency. At this conference the contractor should confirm the testing method, minimum test area, how soon after placement the tests will be performed and submitted as well as the qualifications of the operator. ACI 117 section 4.8.4.4 and ASTM E1155 both require the FF/FL testing to be performed within 72 hours and before removal of supporting formwork. Before stressing of the post-tension cables is also advisable. Designers should explicitly state whether tolerances will be verified with a walking profiler and if laser scanning will be used for additional QC checks. Appropriate use of scanning – Laser scanning can be used to generate heat maps to identify potential issues, but this technology has its limitations. The recent ASCC study recommends only using a TLS for tolerances of ½” or more. Supplementing the FF/FL tests with laser scanner heat map can provide data for very high or low spots that might need to be ground or filled to accommodate final finishes but are not appropriate for FF/FL specification acceptance. Contractors can do their own QC – A walking profiler is ~$10,000 plus the cost to train several operators and time to run the tests. If you need guidance on which companies manufacture them, please contact me at mhernandez@ascconline.org  Multiple ASCC members perform their own FF/FL QC testing immediately after placement and submit this to the GC or design team the next day. This will also provide the ability to discuss the results with the finishers before multiple slabs are placed, and a small problem becomes a large issue. It might be the only record of FF/FL results before the flooring trades arrive on site to look for gaps under a 10’ straightedge. Request raw graphs – As Bill Arpin advises, insist that testing agencies provide profiler plots with every report. Sharp spikes or sawtooth patterns can reveal errors before results escalate into disputes. Foster communication – Most importantly, ASCC contractors and testing agencies must establish a dialogue before FF/FL testing begins. Agree on sampling locations, their interpretation of the ASTM E1155 procedures, and how soon it will be reported. References: ACI Committee 117-10(15), “Specification for Tolerances for Concrete Construction and Materials” ACI Committee 301-20, “Specifications for Concrete Construction” ACI Staff, “Concrete Q&A: Rejecting Floors based on One Sample Measurement Line”, Concrete International, July 2008 Arpin, Bill, “FF/FL Testing Mistakes: Understanding Concrete Floor Profiler Data Better”, ForConstructionPros, https://www.forconstructionpros.com/concrete/equipment-products/flatwork-accessories/article/22909722/somero-matson-group-llc-ff-fl-testing-mistakes-understanding-concrete-floor-profile-graphs-better  Dec 2024 ASTM E1155-23, “Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers,” ASTM International Klinger, Suprenant and Salzano, “ACI Q&A: Operator Qualifications for Determining F-Numbers”, Concrete International, June 2024 Zhang, Hernandez, Dare, Kowalski, and Che, “Interlaboratory Study on Precision Statement of Using a Terrestrial Laser Scanner to Verify Concrete Tolerance” Concrete International, Jan. 2025 Sayde Hindelang Mon, 17 Nov 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:570 https://ascconline.org/Home/News/articleType/ArticleView/articleId/571/September-2025-Guidance-for-Concrete-Contractors43-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=571 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=571&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/571/September-2025-Guidance-for-Concrete-Contractors43-in-a-Series Written by: Jim Klinger,  ASCC Hotline Operator Question:  In the June 2022 issue of the American Concrete Institute (ACI) "Concrete International" magazine, the monthly question-and-answer feature column titled "Concrete Q&A" considered the issue of incidental standing water in a mat foundation area being prepared (and inspected) to receive concrete the following day. In a nutshell, the foundation area comprised edge forms installed all around, with substantial top and bottom layers of reinforcing steel--in place and secured--supported by precast concrete "dobies" resting on a 3-inch-thick unreinforced concrete mud slab. During the pre-pour inspection, the inspector noticed standing water puddled on the top surface of the mud slab-- incidental remnants of a brief afternoon rainstorm at the jobsite the previous day.  Due to the location of the water, about two inches below the outermost bottom layer of reinforcing steel, accurate measurements of the puddle thicknesses were not possible.  By all anecdotal accounts, however, the puddle thicknesses were estimated to be on the order of 1/2-inch to 3/4-inch deep.   The inspector notified the general contractor (GC) that the puddled water would have to be removed before he would sign the work off and allow the scheduled next-day concrete placement to proceed.  This left the contractor with few options.  One option, of course, would be to wait until the puddles (now not exposed to direct sun or wind) dissipated via evaporation. Brooming the water--or attempting to blow the water out of the pour area with compressed air--was not possible due to the tight spacing of the reinforcing steel layers. Another option--cited by the inspector--would be for the placement to proceed as long as the concrete is placed with a full-depth tremie pipe as stated in the ACI Code--namely ACI 318-19 Building Code Requirements for Structural Concrete, section 26.5.2.1(b), which states the following: "(b) Standing water shall be removed from place of deposit before concrete is placed unless a tremie is to be used or unless otherwise permitted by both the licensed design professional and the building official". The ACI Code Commentary for this provision--namely Commentary section R26.5.2.1(b)--states the following: "The tremie referred to in this provision is not a short tube or "elephant trunk". It is a full-depth pipe used in accordance with accepted procedures for placing concrete under water.  Information regarding placing concrete using a tremie is given in ACI 304R. In our opinion, the ACI 318 "tremie option" for placement does not seem rational for use in incidental "birdbaths" ranging from 1/2 to 3/4 inch in depth. As it turns out, the Owner advised the GC on that same afternoon that the architect was making some design changes due to a change in future tenancy, and the concrete placement would be delayed by two to three weeks. Any cost impacts would be funded by the Owner.  In other words, no real harm done. Nevertheless, we are bringing this to the attention of the ASCC Hotline for review and comment.  Answer:  Based on the response to the ACI Concrete International "Q&A" cited above, the ACI Code Committee is slated to review the provisions in Chapter 26 referenced above regarding standing water and requirements for removal (if any) before placement of concrete in an effort to differentiate between placing concrete in water of any appreciable depth as opposed to placing concrete in a relatively shallow birdbath composed of incidental rainwater. But there is another important issue not raised above, and that concerns the approval protocols for the application of section 26.5.2.1(b).  Notice that this section is one of the few that appear in the ACI Code that require concurrent review and approval "by both the licensed design professional and the building official" at the same time. The way we interpret this concurrency requirement, any judgement regarding final approval for a concrete placement to proceed could very likely involve a field review that features the licensed design professional (LDP) accompanying the "building official" (e.g. the inspector) during the inspection such that each condition can be reviewed and permitted--on a case-by-case basis--by both parties. Even more important: this is an opportunity for the concrete contractor to be involved in the conversations. This case highlights one of those conditions that needs to be addressed during preconstruction meetings.  The procedural problem, of course, with the concurrency requirement is making sure the LDP can be made available to visit the jobsite on rather short notice if appropriate. Sayde Hindelang Mon, 17 Nov 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:571 https://ascconline.org/Home/News/articleType/ArticleView/articleId/572/Guidance-for-Concrete-Contractors44-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=572 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=572&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/572/Guidance-for-Concrete-Contractors44-in-a-Series Written by: Jim Klinger,  ASCC Hotline Operator Question:  We are attempting to close out a recent construction contract to build a reinforced concrete mid-rise (6 story) assisted living facility. During the course of construction, the typical 8-inch thick post-tensioned (PT) slabs were placed and finished in approximately 25,000 square foot (SF) pours; then tested with a proprietary "Dipstick" for flatness and levelness by the Owner's test agency. All tested slab surfaces met their required F-numbers within the 72-hour time period specified in the construction documents. In addition, all F-number testing was completed (and reported) prior to any stressing of PT tendons and before the start of any follow-on reshoring activities. Our application for release of retention funds was submitted two months ago following completion (and sign off) of a few minor punch list items (e.g. curbs, pads, and miscellaneous patch items). Unfortunately, we received notice in a meeting today from the general contractor (GC) that our retention payment is in danger of being put on hold, pending resolution of complaints filed by Owner representatives that arose during a recent Architect-Owner job walk. We were advised in today's jobsite meeting that--in an effort to investigate the reported complaints--one of the GC's project engineers performed an informal floor survey using a self-owned laser scanner. The survey was conducted by a room-to-room scan of the oldest floor e.g. the first elevated PT slab. Neither we--nor the project inspector--were notified in advance that such an unofficial laser scan survey was being performed, let alone even being considered. In addition, such "after-the-fact" testing was not discussed in the project preconstruction conference. Truth be told, the thought never crossed our mind. Our understanding is that many of the Owner issues are related to the top slab surfaces and flooring at various locations throughout the building. Evidently, for example, the GC's unofficial "heat map" indicates rooms and hallways that feature areas that are in excess of 3/4 inch below the design top of slab elevation. In other words, the GC survey has found areas where the floor slabs may have deflected. Our position is that the Owner (or the GC) is welcome to survey the floors-at their cost- just as long as the test results will not be used to try and determine contract compliance. That ship has sailed. The Owner's test agency's position is that attempting to determine flatness--after the slabs have been subdivided into so many pieces--by using a Dipstick in accordance with industry standard test methods and protocols will not be possible. Furthermore, the inspector's position is that even the straightedge method--described in industry standard ACI 117-- may not be possible. (N.B.: Now, here we are--several months after the fact--and all the interior partition walls are in place. This effectively subdivides each original 25,000 SF pour area into a series of small rooms and hallways. In addition, flooring has been installed at most locations within the building. We would think that any movements related to the PT or to slab deflections would be most pronounced at the oldest, lowest floors. There is no way anyone could possibly reproduce the original Dipstick runs established by the inspectors when our work was previously tested--and passed). We understand that there are several procedural problems with the withholding of our retention payment. After all, our work was tested when it was supposed to be tested, and it passed within the required time window. We are confident that--eventually--this is all going to be resolved and we will be paid. But, in the meantime, the Owner seems insistent on following the GC's lead and proceeding with an investigation. There was some discussion in today's meeting regarding how testing of F-numbers should be performed so long after the fact--when the access boundary conditions (and Dipstick run line locations) have been drastically changed due to the removal of all shoring and follow-on installation of partition walls and flooring. Although we are relatively new ASCC members, we have become familiar with the ASCC Position Statement collection, especially those related to concrete floor slab finishes; including Position Statement #6: "Division 3 versus Division 9 Floor Flatness Tolerances".  In part, Position Statement #6 addresses surveys of floor flatness that are conducted long after the concrete has been placed, finished, tested, and passed. Thanks to other ASCC (and ACI) documents, we understand that elevation surveys of PT slab surfaces conducted several months apart can often have completely different results--none of which are the concrete contractor's responsibility to address. Going forward, we are looking to the ASCC Hotline to provide comments and guidance.  Answer: Welcome to the ASCC Hotline. As you have stated, there are several procedural problems with the Owner's position and proposed course of action, incomplete as it is. You are correct in noting that your work met your construction document Quality requirements.  It appears that both the concrete slab installation and the subsequent testing were performed in a timely manner, "by the book". And it is no surprise to us to hear that there are areas in the building that--even though the laser scan is unofficial-- apparently have shifted outside of the floor flatness and slab elevation design envelopes as indicated in the construction documents. You are also quite correct in taking the position that the Owner (or anyone else) is welcome to pay all costs to conduct slab surveys any time they want--as long as the results are not used as an excuse to relieve you of some (or all) of your retention dollars.  (It should also be noted here that the unofficial laser scan survey conducted by the GC does not constitute "additional testing" as described in ASCC Position Statement #34: "Who Pays for Additional Testing?", since such GC testing was not triggered by failing test results when the original, official F-number tests were conducted by the Owner's test agency). At this point, we recommend you forward--at a minimum--a copy of ASCC Position Statement #6 to the GC, who should in turn send this information upstream to the design team and the Owner for their consideration. The questions then become "How should such an after-the-fact, top of slab elevation survey be conducted?  What test apparatus (e.g. instruments) and test procedures should be used? According to your construction documents, the basic Quality requirements governing the reinforced concrete portion of your scope are derived from industry standards established by the American Concrete Institute (ACI) and ASTM International (ASTM), formerly known as the American Society for Testing and Materials. For example, general Quality requirements for construction of reinforced concrete slabs (e.g. tolerances for slab formwork, location, thickness, surface finish, etc.) are specified in ACI 117: Specification for Tolerances for Concrete Construction and Materials and Commentary. On the other hand, specific requirements and protocols for the available test methods used by the Owner's test agency to determine concrete floor surface flatness and levelness numbers (aka "F-numbers") are specified in ASTM E1155: Standard Test Method for Determining Ff Floor Flatness and Fl Floor Levelness Numbers. ASTM E1155 section 6 contains provisions for the various types of apparatus that may be used.  Type I apparatus options, for example, could include: leveled straightedge, optical level, laser level, or a laser imaging device (e.g. laser scanner).  If a Type I apparatus is not used, then Type II options could include certain inclinometers or floor profiling devices. The issue of appropriate test procedures and apparatus that should be used to determine F-numbers is addressed--albeit in nuanced fashion--within the ASTM E1155 document itself.  In standard E1155, "Note 3" appears as follows: At first glance, one might get the impression that all project participants would hold a meeting to discuss, then agree on the exact test apparatus (e.g. laser imaging device, leveled straightedge, "Dipstick", and so on) before embarking on any test program that will be used to enforce contract specification compliance.  Presumably, this mutual, sensible agreement among all project participants could be reached--using pre-bid RFI's--during the bid period.  In practice, however, it is more likely that such discussion and agreement would be reached during the preconstruction conference.    Well, not so fast.  Upon further review, it turns out that ASTM E1155 Note 3 is only an informative, non-binding suggestion.  In other words, the phrase "should agree" as stated in Note 3 (above) is not equal to "must agree" or "shall agree". The bottom line is the choice of methodology resides with the entity performing the tests. How do we know this? ASTM Standard E1155 section 1.2 states: Drilling into the issue deeper, we find guidance presented in the ASTM International "Form and Style for ASTM Standards" document that clarifies the intent of "Notes" that appear in ASTM standards. Section A27.1 of the ASTM style guide appears as follows: "A27.1 Notes in the text shall not include mandatory requirements. Notes are intended to set explanatory material apart from the text itself, either for emphasis or for offering informative suggestions, which are not properly part of the standard. Clarification of the description of required apparatus or procedure and modifications required or permitted in certain cases belong in the text itself. If inclusion of the contents yields a different result, then that information is considered mandatory for the performance of the standard and shall be located in the text. Notes may be preferable for detailed description of auxiliary procedures (for example, correction of barometric pressure in a test method not primarily concerned with pressure). Table notes are a part of the table and are mandatory provisions." ____________________________________________________________ NOTE 1: It is not at all unusual for the GC to look to the concrete contractor to provide an agenda for the preconstruction (aka "pre-pour") conference. As it turns out, just such a comprehensive agenda has been prepared jointly by the National Ready Mixed Concrete Association (NRMCA) and the ASCC.  Titled "Checklist for the Pre-Construction Conference", this joint document provides line-item discussion points covering topics that range from Quality testing of fresh concrete (e.g. slump, air) to testing of hardened concrete (e.g. compressive strength acceptance specimens, floor flatness, floor levelness, etc.). A link to the Joint NRMCA/ASCC Pre-Construction checklist is here: https://www.nrmca.org/wp-content/uploads/2021/06/1PreconstructionChecklist.pdf For example, the NRMCA/ASCC preconstruction checklist section B ("Construction Process"), item #18 provides a comprehensive series of discussion points that will help provide clarity regarding floor flatness and levelness, and how such Quality items will be determined. As many ASCC Hotline callers know, money can often be saved simply by methodically performing our concrete scopes using various ASCC checklists.  Access to the ASCC checklist collection--in addition to the collection of ASCC Position Statements--has proven over the years to be a valuable, proven member benefit. As mentioned above, the GC often requests the concrete contractor draft the agenda for the preconstruction conference. Unfortunately, in the case of the Hotline call described above, the NRMCA/ASCC checklist was not incorporated into the preconstruction meeting. ____________________________________________________________ NOTE 2: Although not discussed in the Hotline call above, not only are the procedures and apparatus for flatness and levelness testing important, but the qualifications of the device operator are crucial as well. Unfortunately, both ACI and ASTM documents are silent on training, qualifications, or certifications for operators determining F-numbers. This was discussed at length in the September 2023 issue of ACI Concrete International's "Concrete Q&A" titled "Operator Qualifications for Determining F-numbers". This important item should be discussed in the preconstruction conference, in addition to the topics described above. Sayde Hindelang Mon, 17 Nov 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:572 https://ascconline.org/Home/News/articleType/ArticleView/articleId/558/August-2025-Guidance-for-Concrete-Contractors42-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=558 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=558&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/558/August-2025-Guidance-for-Concrete-Contractors42-in-a-Series Written By: Jim Klinger, Concrete Expert Question:  We have an opportunity to bid a portion of the reinforced concrete scope on an upcoming industrial/manufacturing plant and adjacent support building project (e.g. parking garage and two steel office buildings) which is slated to break ground next month. The Owner is releasing the work in phases (aka "bid packages") driven by structure type, material availability, Owner financing, and seasonal weather considerations consistent with the jobsite geography. For this project, the Owner envisions having the reinforced concrete foundation portions of each structure "in place and cured" before winter sets in. In our case, the task at hand is to prepare a price proposal for "Bid Package #1: Early Foundations". According to project details advertised by the general contractor (GC) during last week's pre-bid conference, the foundations we are to bid include a reinforced concrete mat foundation for the post-tensioned (PT) parking garage; and reinforced concrete pile cap/grade beam systems for the manufacturing plant itself and its two adjacent mid-rise structural steel support buildings.  According to the Owner's schedule, once the foundation mat for the PT garage is in place, construction of the upper floors can proceed through the winter months as long as we follow the approved cold-weather concrete construction plan we are required to submit as part of our Bid Package #1 scope. In other words, construction of the PT garage can proceed as normal, with no interruptions.  But the ongoing design of the structural steel frame for the manufacturing plant introduces potential schedule hiccups into the equation.  According to the design team, the design of the upper portion of the steel frame is partly dependent on the vibration loads introduced into the base structure by the manufacturing equipment. That equipment is still in the design phase overseas (Germany).   In his presentation at the pre-bid conference, the structural engineer told us the Owner expects further delays once the manufacturing plant equipment is fully designed due to reported material supply chain--and even potential tariff--issues.  Nevertheless, the Owner wants to hedge his bets and have the foundation for the manufacturing plant in the ground as soon as possible. Normally, our traditional scope of construction services only includes work items directly related to reinforced concrete construction.  For example, we include structural excavation of spread footings, but we exclude mass excavation and offhaul of spoils.  We include localized dewatering--in an elevator pit, for example--but we exclude mass geotechnical dewatering.  We include setting of almost all items shown to be embedded in the concrete that we place, but we do not supply any embedded items. On this project, however, the Owner is "calling an audible" and requiring the concrete Bid Package #1 bidders to include the furnishing of structural steel anchor rods, weld plates, embedded plates, embedded shapes (e.g. small lengths of W-shapes or channel shapes as shown) and so on into our scope. Ordinarily, such a scope would be picked up by the structural steel supplier, or even the structural steel erector. Our initial reaction was "Why doesn't the GC solicit bids for the supply of the embedded steel items? The GC's position:  the concrete contractor must become familiar with the embedded items anyway--quantities, types, sizes, locations--in order to price their setting. Once quantities and types are known, soliciting prices should be the logical next step.  Since we anticipate being asked to bid on subsequent bid packages on this project over the next few years--including a substantial site concrete scope--we decided to take on this task of embed supply for the embeds that are shown to be set in the manufacturing plant pile caps, grade beams, and slab on grade.  And that business decision is what has prompted our call to the ASCC Hotline.  During the design team's presentation at the pre-bid conference, the structural engineer made several emphatic comments regarding the grade of structural steel. Example comment: "Make sure that the steel that is used in the fabrication of the embedded shapes has been fully killed."  Questions to the Hotline then become: --What is fully killed steel...and how could killed steel affect our price? Answer: This is an item that might be worthy of a pre-bid RFI to the structural engineer.  By all rights, the structural construction documents (usually the "General Notes" sheets) should identify the American Society for Testing and Materials (ASTM) Standard grade for each of the various structural steel members to be used in the project--including embedded steel material.  Concrete contractors should already be familiar with commonly used ASTM steel grade designations such as ASTM grade A36, for example, or ASTM grade A572. Therefore, when your estimator is tabulating the embedded item quantities in a spreadsheet, we suggest creating a column that lists the ASTM Standard grade for each embed mark for material tracking and pricing purposes. The term "killed steel" is not new to the industry, and is related to the chemical composition--and behavior--of the steel as it is produced from molten to hardened (cast) material in the steel mill.  The idea is to deoxidize the steel by adding either Aluminum (Al) or Silicon (Si) while the steel is still molten. Once the steel is ladled (cast) into the molds, the added Al or Si keeps the material from developing gas bubbles during solidification.  Since the steel essentially lays still in the mold (no gas bubbles develop), it is then said to have been "killed". The end result is steel with less porosity. The requirement for killed steel appears in ASTM A992: Standard Specification for Structural Steel Shapes, section 4.1 as follows: "The steel shall be killed, and such shall be confirmed by a statement of killed steel on the test report, or by a report on the presence of a sufficient quantity of a strong deoxidizing element, such as silicon at 0.10% or higher, or aluminum at 0.015% or higher." Any cost impacts will have to come from your steel supplier of choice. The key is letting your supplier know what material has been called out as ASTM A992 (as opposed to, say, ASTM A36 or ASTM A572 material, for example) so they can advise you if there is any price impact. We suggest you supply the project bid documents to each steel supplier and you can compare their estimate with yours. After that exercise, a pre-bid RFI to the design team probably won't be necessary, since any "premiums" will already be rolled into the supplier's pricing to you. Question: Is there any document that says footings must be formed and not trench poured? Is this part of any Code that you are aware of?  We have a township official telling us this is an ACI requirement. Answer:  The above Hotline questions originally appeared in the October 2012 ASCC Voice newsletter. A link to an updated version of the 2012 original Voice article can be accessed online here: Updated Article Here. In addition to the update of the original 2012 article, what follows below are supplemental comments that reflect document changes, Code updates, and knowledge gained from 13 years-worth of field experience. At issue is the question that all concrete estimators ask themselves when the structural drawing foundation plans are unrolled on day one of the quantity takeoff for a new concrete construction project: "will we have to form the vertical foundation sides, or will the jobsite soil conditions (or design requirements) allow us to cast the foundation concrete directly against earth?" (N.B.: Although we have not seen this explained in the current literature, the so-called "neat-cut" method is almost always going to benefit the Owner in terms of time and dollars.  After all, the "formed sides" option has several activities that the neat-cut method does not have, namely over excavation, furnish formwork material, erect foundation side forms, strip form sides, patch formed faces (if needed), and backfill/compact soil against the formed sides. The downside of neat-cutting, of course, is risk. Once you commit to neat-cutting in your bid proposal, you own the work whether it ends up being neat cut or formed.) The first step in answering the question of whether or not to form foundation sides is to examine the bid documents to determine if the design team has somehow prohibited the so-called "neat-cut" method of casting foundation concrete directly against earth. Such prohibitions might appear in typical drawing details or in specific section cuts taken through the foundation.  We have also seen such prohibitive requirements expressed in project specifications. The second step is to carefully examine the soil borings and recommendations that appear in the project geotechnical report (aka the "soils report"). Certain soil conditions--borings that reveal dry, loose, sandy soil, for example--are quick indicators that the footing sides cannot stand after excavation without sloughing and collapsing. The third step is to carefully examine the construction documents for waterproofing requirements, if any, that can be a factor when sides of the foundation elements (including elevator pits) are to be formed.  In many cases, once forms are stripped, supplemental patching may be required to accommodate follow-on waterproofing applications. We recommend the bid team review ASCC Position Statement #27 Formed Surface Requirements for Waterproofed Walls if foundations require forming. A link to the latest ASCC Position Statement #27 is here: https://ascconline.org/Portals/ASCC/Files/Position%20Statements/PS-27_FormedSurfaceRequiremts_webSC-1.pdf?ver=U7QefaD9st_owBZfsZPwHA%3d%3d Although the ACI Code is silent regarding forming of foundation sides, the International Building Code (IBC) is not.  IBC 2021 section 1808.8.5 Forming of concrete states: "Concrete foundations are permitted to be cast against the earth where, in the opinion of the building official, soil conditions do not require formwork. Where formwork is required, it shall be in accordance with section 26.11 of ACI 318". Sayde Hindelang Fri, 15 Aug 2025 18:02:00 GMT f1397696-738c-4295-afcd-943feb885714:558 https://ascconline.org/Home/News/articleType/ArticleView/articleId/557/August-is-National-Traffic-Awareness-Month#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=557 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=557&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/557/August-is-National-Traffic-Awareness-Month Written By: Joe Whiteman, CSP, CHST, Director of Safety Services August is recognized as National Traffic Awareness Month—a timely reminder of the critical role traffic safety plays on and around our jobsites. For concrete contractors, managing traffic hazards extends beyond the open road; many of our most significant risks occur where public roadways meet active construction zones. The movement of equipment, deliveries, and crews requires constant vigilance to protect both workers and the public. Concrete pump truck setup is one of the most visible—and potentially hazardous—traffic interactions we manage. These trucks often require positioning along or near active streets, driveways, or site access points. Proper traffic control plans, effective flagging, and clear communication with both the crew and the public are essential to avoid dangerous conflicts. Similarly, ready-mix trucks delivering concrete frequently enter and exit sites throughout the day. Tight schedules, unfamiliar site conditions, and the need to reverse into pours can create high-risk situations if traffic flow and access are not managed effectively. It’s not just concrete deliveries that require attention—construction materials such as rebar, formwork, and equipment arrive regularly and often must be staged or offloaded in areas with active traffic. Coordination with suppliers, establishing staging areas that minimize public interaction, and consistent use of spotters during unloading are key steps in reducing exposure. These precautions not only protect our workers but also reinforce our commitment to public safety. Adding another layer of complexity, August also marks the return to school in most parts of the country. Increased school zone activity means more pedestrians, buses, and distracted drivers during morning drop-off and afternoon pick-up times. If your project is near a school or along a bus route, be especially mindful of these peak traffic periods. Allow extra time for deliveries, reinforce vigilance at access points, and communicate with crews about heightened awareness in school zones. Traffic safety is an ongoing responsibility for every ASCC member. By taking proactive steps—from detailed traffic control planning to heightened awareness during high-risk times—we can protect our crews, safeguard the public, and maintain our industry’s strong reputation for safety. Sayde Hindelang Fri, 15 Aug 2025 16:15:00 GMT f1397696-738c-4295-afcd-943feb885714:557 https://ascconline.org/Home/News/articleType/ArticleView/articleId/556/Greater-Degree-of-Collaboration-on-Next-Generation-of-Blended-Cement#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=556 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=556&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/556/Greater-Degree-of-Collaboration-on-Next-Generation-of-Blended-Cement Greater Degree of Collaboration on Next Generation of Blended Cement Written By: Michael Hernandez, Technical Director Excited to announce that ASCC has already received agreement from more than ten of the largest cement manufacturers in the U.S. to openly communicate, through ASCC, with member contractors about any future blended cement introductions. Each new blended cement will be unique from plant to plant based on SCM availability and market needs. Most plants are already producing IL. This initiative would cover future IL with a higher limestone percentage, IS (slag), IP (pozzolan), or IT (clinker + two SCMs) blended cements. The goal is to avoid surprises and enable members to present options to owners with aggressive low-carbon concrete goals. I can provide you with the point of contact at each manufacturer if you send me an email with a specific request at mhernandez@ascconline.org. Part of the process of introducing a new cement blend involves cement manufacturers providing sample buckets to their customers—ready mixed producers. When a new cement is released, ready mixed producers will usually run lab trials with their own materials and admixtures. Last month, in The Slab (July 2025 issue), Master Builders Solutions provided a paper describing the process for evaluating multiple admixtures and material combinations in small batches. You can read it here: Mortar-to-Mix Procedure for Evaluating Cementitious Materials and Chemical Admixtures The next step is field evaluations. This is an ideal time to ask if the concrete can be placed and finished by your team, so you can gain firsthand understanding of how it performs in the field and provide feedback to both ready mixed and cement representatives. To simplify the search for cement plants located nearest your office or a project, here is a QR code link to a Google Map with every cement plant in the U.S. You can zoom in to view each plant via satellite. Tons per year produced are approximate (+/- 10–15%) and intended to provide a general sense of scale. We have additional data available about what most of these plants are currently manufacturing, which will be posted on the ASCC website (far right tab after logging in). If you would like a large wall map that includes cement plants and transfer terminals (rail-to-silo-to-truck) or the cement directory with addresses, phone numbers, and contacts, they can be purchased here: National Cement Directory The continued increase in communication between concrete contractors, ready mixed producers, and cement manufacturers is an excellent way to mitigate risk by improving understanding of critical material availability and enabling testing before market release. Parallel to the Indianapolis ASCC Annual Conference, on Wednesday, September 10, 2025, there will be a blended cement workshop from 11:30 a.m. to 4:30 p.m. The program will include: Information about blended cement Insight into cement manufacturing Ready mixed resources A producer quality control testimony Plastic concrete performance evaluation Two case studies A roundtable discussion to conclude the session Registration information will be available by mid-August. Sayde Hindelang Fri, 15 Aug 2025 16:02:00 GMT f1397696-738c-4295-afcd-943feb885714:556 https://ascconline.org/Home/News/articleType/ArticleView/articleId/554/PRO-Focuses-on-Concrete-Construction-Productivity#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=554 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=554&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/554/PRO-Focuses-on-Concrete-Construction-Productivity From: Phil Diekemper, Executive Director – PRO: An ACI Center of Excellence for Advancing Productivity  Poorly coordinated and/or incomplete design drawings result in inaccurate bids, and they force contractors to complete the needed coordination and design through multiple requests for information (RFIs). The disjointed process leads to delays, added costs, change orders, and a general dissatisfaction with the completed project. A set of documents that is complete and coordinated before construction is essential for achieving productivity. In 2023, FMI Corporation released a labor productivity study. According to the 2023 FMI Labor Productivity Study, “4 of 5 Contractors said low-quality design/construction documents (plans and specs) are a top external factor stunting productivity.”1 While design team members use their education and experience to translate architectural concepts into a constructable format, construction team members use their knowledge and experience to construct the project with a focus on cost and schedule. The design process may include the evaluation of a variety of concepts and solutions. The construction process typically seeks maximum productivity. Changes during construction caused by incomplete and/or poorly coordinated documents are not good for a contractor’s productivity. In 2020, ASCC conducted a Constructability Survey. The ASCC survey indicated that the No. 1 barrier to constructability was a lack of completeness of drawings, with the coordination of drawings second and the coordination of drawings and specifications third. Concrete embedded items from specialty structural engineers (for example, cladding) need to be provided and coordinated by the structural engineer of record (SER), even though those details are often provided during the concrete construction phase. Beware of standard details. Standard details can be added to the drawings without much thought and often conflict with the designers’ intent or other project-specific details. This can lead to ambiguity, conflicts, and change orders. Designers face many pressures during the design process, and these can result in negative impacts on the constructability of the construction documents. These pressures include: Increased competition; Lower design fees; Accelerated design schedules; Increased architectural design complexity; Owner decision delays and changes; Delegation of responsibilities for design and coordination; Accelerated project delivery; Inability to retrain experienced staff and train the less experienced; and Increased reliance on design technology. To address these concerns, many organizations, such as the Council of American Structural Engineers (CASE), Construction Specifications Institute (CSI), American Society of Civil Engineers (ASCE), International Code Council (ICC), American Concrete Institute (ACI), and ASTM International, have published requirements and guides. I will touch on these in future newsletter articles. Project owners should learn that low design fees, insufficient design time, and increased project complexity that prevent designers’ completion of needed document coordination and constructable designs ultimately increases project cost and time as an expense to the owner. Construction agreements have sprouted new language that exonerates designers while increasing contractor risks. Language that suggests the contractor’s estimate should anticipate and include the designer’s intent, not necessarily what is included or expressed in the documents. Does that include information not included or expressed? What are the limitations of such agreements? Such attempts to deflect responsibility to the concrete contractor become sources of conflict, disagreements, arbitration, and litigation. Send your examples of these onerous agreements to Phil.Diekemper@concreteproductivity.com. PRO seeks to address incomplete and poorly coordinated construction documents, as well as deceptive agreements that are barriers to concrete construction productivity. 12023 FMI Labor Productivity Study Sayde Hindelang Thu, 31 Jul 2025 17:03:00 GMT f1397696-738c-4295-afcd-943feb885714:554 https://ascconline.org/Home/News/articleType/ArticleView/articleId/553/Mortar-to-Mix-Procedure-for-Evaluating-Cementitious-Materials-and-Chemical-Admixtures-Optimizing-Concrete-Performance-Regarding-Workability-Setting-Characteristics-Heat-of-Hydration-and-Compressive-Strength-Results-Using-Calorimetry-and-Maturity#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=553 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=553&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/553/Mortar-to-Mix-Procedure-for-Evaluating-Cementitious-Materials-and-Chemical-Admixtures-Optimizing-Concrete-Performance-Regarding-Workability-Setting-Characteristics-Heat-of-Hydration-and-Compressive-Strength-Results-Using-Calorimetry-and-Maturity Tom Pelo, Jeff Huff, Tarek Khan, and John Luciano (Retired) Master Builders Solutions Admixtures US LLC – June 2025 Introduction Given the recent interest in low-embodied carbon concrete (LECC), there are new cementitious materials, multiple supplementary cementitious materials (SCM) and admixture chemistries available to reduce the embodied carbon content of concrete. For example, Type IL cement was recently introduced in most US markets. These materials can affect the performance of concrete negatively, especially with respect to setting times and strength development. Master Builders Solutions has developed a procedure using concrete mortars to quickly evaluate combinations of raw materials to assess their performance that is based on ASTM C1810, Standard Guide for Comparing Performance of Concrete-Making Materials Using Mortar Mixtures, particularly, “Method A, Mortar Proportioned Based on Job Concrete Mixture Proportions”1. The information gained from this small-scale, assessment procedure can be used to quickly screen multiple combinations and reduce the requirements for large-scale concrete testing. Following are procedures and testing protocols that have been used by Master Builders Solutions personnel and others in the lab and the field. Typically, the procedure requires only ten minutes to complete a single batch. In addition to physical tests on the mortar, calorimetry and maturity testing establish broad differences in setting time and strength development performance. Others have done similar work and found reproduceable results on a consistent basis.2 Guidance It’s suggested that a thorough testing plan be developed that addresses the project’s concrete requirements, for example high-early strength, setting-time needs, and longer- term strength development. It’s imperative to use locally available concrete sands due to the high variability of aggregate properties that affect water demand and strength, for example cleanliness, soundness, and clay content. This in contrast to ASTM test methods for testing the strength of cements made with mortar containing ‘standard sand’, i.e., “Ottawa” sand. Concrete sand has an influence on concrete properties, especially the required water content to make workable, placeable concrete before the addition of water- reducing admixtures. Consider the workability requirement for the concrete; for example, will the concrete be pumped, will it be flatwork that’s finished by hand or machine-troweled, or will it be placed in a form? Each requires a different water content and water-reducing admixture combination. Early indications of each of these properties can be established following this procedure. The moisture content of the sand should be determined immediately prior to testing so that the added water content can be adjusted based on the SSD specific gravity and the measured moisture content. This procedure is typically run at 70°F but it can be run at the anticipated concrete temperature by adjusting the temperature of the mixing water, the sand, and cementitious materials. Plan on batching approximately 0.35 ft3 of mortar. This batch will yield enough mortar for ten 3 X 6-inch test cylinders or four 4 X 8-inch cylinders with sufficient materials to run a mini-slump3 and 0.5L mortar meter.4 Batches could be mixed in a Hobart mixer as outlined in ASTM C1810, which requires multiple batches for larger quantities. Procedure Pre-weigh the sand in a 5-gallon bucket. If necessary, pre-cool or pre-heat the sand using a refrigerator or hot plate to match the anticipated concrete temperature. If needed, add the air-entraining admixture on top of the sand. Pre-weigh cements and SCMs in a 3-gallon bucket. Pre-weigh water and water reducing admixture(s) in a separate bucket. If necessary, adjust the water temperature using ice or hot water, to match the anticipated concrete temperature. For extreme temperatures, the sand and cementitious materials can be pre-cooled or pre-heated to achieve the anticipated concrete temperature in production and placement. Mixing procedure: Dump the cement (and any SCMs) on top of the sand in a 5-gallon bucket. Immediately add water with chosen admixture dosage Mix at medium to high speed with the Milwaukee Mud Mixer5, for 60 to 90 seconds. Scrape sides of bucket to ensure all materials are thoroughly mixed. Measure the temperature of the prepared mortar. Perform the mini-slump/spread test based on the desired mortar consistency. Perform the air test with mortar air meter6. Fabricate the required number of 3 X 6-inch cylinders for compressive strength testing. Store the cylinders in the Calmetrix, F-Cal calorimeter7 and EXACT Technology Match Curing chamber 8 as indicated in the testing plan. Perform the thermal indication of set (TIS) using the Calmetrix, F-Cal calorimeter7. Break the test cylinders at times that match the project requirements, for example 12 hours, 1-day, 2-days, etc. Correlate the compressive strength test results with the data from Calmetrix and EXACT Match equipment. Develop the maturity curve using the appropriate EXACT Technology equipment8. About Calorimetry The reaction between cement and water (called ‘hydration’) is exothermic, that is, it generates heat. By measuring the heat outflow using a calorimeter, which tracks the temperature of the hydration reaction, one can understand the behavior of concrete or mortar. Simple set time or compressive strength tests do not show this much information. Calorimetry measurements will indicate the effectiveness of admixtures on the hydration reaction, thereby allowing decision makers to optimize cement, SCM and admixture combinations for a given project’s specific needs. The data generated by the thermal indication of set (TIS) measurements allows us to predict initial and final setting times (i.e., the ‘finishing window’) for a given combination of materials. In our experience, the F-Cal 8100 semi-adiabatic calorimeter provides the functionality and ease of use for lab or field testing for concrete tests. The Calmetrix team is supportive and can further explain the use of their equipment. For more information, visit: https://www.calmetrix.com/ Note that the recommended equipment follows ASTM C1753 "Evaluating Early Hydration of Hydraulic Cementitious Mixtures Using Thermal Measurements".9 The F-Cal 8100 unit is described here: https://www.calmetrix.com/f-cal-calorimeters There’s a link called “Concrete Testing” at the bottom of that page to multiple short videos and an hour-long webinar on the Calmetrix YouTube channel. Consult Calmetrix for cost information and the hardware requirements for the laptop computer or tablet needed to capture data. About the Maturity Concept The maturity concept utilizes the same premise that calorimetry uses; namely that the hydration reaction generates heat. According to the National Institute of Standards and Technology, “the maturity method is a technique to account for the combined effects of time and temperature on the strength development of concrete. The method provides a relatively simple approach for making reliable estimates of in-place strength during construction.”10 The method depends on establishing an accurate calibration curve by casting enough cylinders to determine the strength of concrete over time, typically 12 to 72 hours, and then ‘matching’ those strengths to the measured time-temperature data. Future concrete placements will not require cylinders to be cast and broken; rather the time- temperature data is collected and recorded using temperature sensing equipment. More detailed information about the maturity method can be found in ACI 228.1R-19, “Report on Methods for Estimating In-Place Concrete Strength”.11 There is an ASTM practice for estimating strength using the maturity method.12 A simple discussion of using the maturity method is presented in “Concrete in Practice 39 Maturity Methods to Estimate Concrete Strength”.13 The engineers that founded EXACT Technology come from the concrete construction industry and can explain the maximum effectiveness of this concept. For more information, visit https://www.exacttechnology.com/ Consult EXACT Technology for cost information and the hardware requirements for the laptop computer or tablet needed to capture data. About Master Builders Solutions We offer advanced chemical solutions for new concrete construction and underground construction in the U.S. and Canada. Our brand is built on more than 100 years of experience in the construction industry. Our comprehensive portfolio encompasses concrete admixtures, cement additives, macro, and microfiber reinforcement for concrete and chemical solutions for underground construction. To solve our customers’ specific construction challenges from conception through to completion of a project, we draw on our specialist know-how, regional expertise and the experience gained in countless constructions projects worldwide. We leverage global technologies, and our in-depth knowledge of local building needs to develop innovations that help make our customers more successful and drive sustainable construction. Master Builders Solutions Admixtures own lab in Cleveland, Ohio is available to provide services for concrete producers and contractors. Find a local Master Builders Solutions representative by using the link at the bottom of this page: https://master-builders- solutions.com/en-us/contacts/ Alternately, you may contact the authors. Tom Pelo is a Development Manager, based in Montana, who works across the Western United States. Reach him at tom.pelo@masterbuilders.com Jeff Huff is a Senior Territory Manager in Western Washington and Northwestern Oregon. Reach him at jeff.huff@masterbuilders.com Tarek Khan is a Business Development Manager, in Master Builders Solutions Admixtures’ Concrete Sustainability Group. He is based in California and works across the United States. Reach him at tarek.khan@masterbuilders.com John Luciano is retired from the Master Builders Solutions, having worked in the research and development group in Cleveland, Ohio for over 40 years. Footnotes ASTM C1810 “Standard Guide for Comparing Performance of Concrete-Making Materials Using Mortar Mixtures”, published by ASTM International, available here: https://www.astm.org/ “Laboratory Paste Mixtures as a Concrete Mix Design Tool”, an American Concrete Institute Web Session presented by Tim Cost, available here: https://www.concrete.org/publications/getarticle.aspx?m=icap&pubid=51686537 (free to ACI members) and “Mortar Testing for Estimating Strength”, by Joseph J. Daczko, Published in Concrete International, by the American Concrete Institute, September 1999, available here: https://www.concrete.org/publications/internationalconcreteabstractsportal.aspx?m=det ails&id=277 (free to ACI members) ASTM C1437 “Standard Test Method for Flow of Hydraulic Cement Mortar”, published by ASTM International, available here: https://www.astm.org/ ASTM C185 “Standard Test Method for Air Content of Hydraulic Cement Mortar”, published by ASTM International, available here: https://www.astm.org/ “Milwaukee M18 Fuel 18V – ½-inch Mud Mixer”, available from Milwaukee Tool https://www.milwaukeetool.com/Products/2810-22 “Humboldt Mortar Air Meter”, available from the Humboldt Construction Materials Testing Equipment https://www.humboldtmfg.com/air-entrainment-meters-for-mortar- actual.html “F-Cal 8100 Portable semi-adiabatic calorimeter” (requires software installation and suitable computer), available from Calmetrix https://www.calmetrix.com/ “EM1” or “EM2” Curing chambers (requires software installation and suitable computer), available from EXACT Technology https://www.exacttechnology.com/ ASTM C1753 "Evaluating Early Hydration of Hydraulic Cementitious Mixtures Using Thermal Measurements", published by ASTM International, available here: https://www.astm.org/ “The Maturity Method: from Theory to Application”, by N.J. Carino and H.S. Lew, published by The Building and Fire Research Laboratory at the National Institute of Standards and Technology. This document is in the public domain here: https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860356 ACI 228.1R-19, “Report on Methods for Estimating In-Place Concrete Strength”, published by the American Concrete Institute, available here: https://www.concrete.org/store/storeresults.aspx?Keyword=228.1 “ASTM C1074 “Standard Practice for Estimating Concrete Strength by the Maturity Method”, published by ASTM International, available here: https://www.astm.org/ “Concrete in Practice 39 Maturity Methods to Estimate Concrete Strength”, published by the National Ready Mixed Concrete Association, available here: https://www.nrmca.org/wp-content/uploads/2021/01/39pr.pdf Mortar to Mix Procedure – Equipment List Typical setup – 5-gallon bucket (not shown) Milwaukee M18 Fuel 18V – ½” Mud Mixer – Available here: https://www.milwaukeetool.com/Products/2810-22 Mud Mixer Paddle – Dual Stage 5” wheels – Available here: https://www.krafttool.com/DC310?srsltid=AfmBOopiVd1raLF_JmUP1WnmHuVN_8ivrdvJY ZJ22Rrj5LfLoz1jWXB7 Digital Temperature Gun – accurate to 0.5 degrees F Electronic Calipers – accurate to 1 mm 5” Mortar Cone – Available here: https://www.americancubemold.com/Mini-Steel-Slump- Cone-p/acm-32mn.htm Plexiglass sheet 24” X 36” – 1/8” 3” by 6” and 4” by 8” Plastic Cylinder Molds (not shown) Prepared Mortar – Entrained Air Analysis Prepared mortars are tested with .5-liter mortar air meter to determine entrained or entrapped air content, such as the Humboldt Mortar Air Meter – H-2847 - .5L Mortar Air Meter Available here: https://www.humboldtmfg.com/air-entrainment-meters-for-mortar-actual.html Calorimetry Testing – Thermal Indication of Setting Characteristics F-Cal 8100 semi-adiabatic calorimeter connected to a laptop Sample heat of hydration curve Prepared mortar samples in 3”X6” plastic cylinder molds are placed into the Calmetrix F- Cal 8100. Up to 8 prepared mortars can be tested simultaneously. Heat of hydration is measured and can then be converted into analysis logs for estimating setting times and strength prediction. More information is available at: https://www.calmetrix.com/f-cal-calorimeters Maturity Curve Testing – EXACT Technology Equipment EM1 Match Cure Box The EM1 unit enables cylinder curing to match temperatures of in-place concrete. Data loggers with attached probes are inserted into concrete member. The temperature is measured and relayed to the curing box, which cures cylinders at the same temperature as the in-place concrete members. EM2 Match Cure Box The EM2 Match Curing unit is a programmable curing box capable of curing cylinders at temperatures ranging from 40 to 140 degrees F. Temperatures can be held constant or can be varied. The EM2 provides time-over-temperature graph, which can be combined with compressive strength information, to formulate maturity curves based on the data. More information is available at https://www.exacttechnology.com/ Sample Calorimetry Data Sample Maturity Data Sayde Hindelang Fri, 25 Jul 2025 17:41:00 GMT f1397696-738c-4295-afcd-943feb885714:553 https://ascconline.org/Home/News/articleType/ArticleView/articleId/552/July-2025-Guidance-for-Concrete-Contractors41-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=552 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=552&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/552/July-2025-Guidance-for-Concrete-Contractors41-in-a-Series Jim Klinger, Concrete Construction Specialist The Slab Newsletter July 2025 Question:  We just returned to our office from a mandatory project kick-off meeting with major project stakeholders, including the Owner (a well-known, high-profile winemaker), the architect, the structural engineer, and the general contractor (GC). Based on a few of the meeting discussion topics, we now find ourselves in a difficult situation regarding jobsite access and logistics. We are hoping a call to the ASCC Hotline will provide some relief. We were originally issued a Letter of Intent (LOI) for this project, which we successfully bid during the fall of 2019--before the COVID pandemic hit and caused the winemaker to suspend all work on capital construction projects (including new construction, existing facility upgrades, and retrofits). Groundbreaking on our project was slated to occur in January 2020, with our mobilization onsite scheduled soon thereafter. When we received notice from the GC that the project was being shelved, we were assured that the job was only being suspended--not cancelled--and that the Owner didn't want any part of putting the job back out on the street for a rebid.  In other words, this was our job, only with a start date unknown. In addition, we were assured by the GC that all stakeholders would be equitably compensated for all material escalation costs, supply-chain costs, labor escalation costs and so on related to the pandemic shutdown as outlined in ASCC Position Statement #45- "Managing Concrete Projects: Concrete/Steel Price and Delivery Volatility Risks". Now here it is some five years later; and--true to their word--the financing to cover all of the escalated project costs for all parties is approved and in place. The mobilization date for our scope is now slated for October 2025. With that bit of good news, then, what could be so difficult? Here's some background information.  We are a well-established concrete "place-and-finish-only" contractor. But we are slowly expanding our scopes of service. We routinely perform pump-place-finish work on large commercial projects, including concrete high rises, structural steel towers (slabs on metal deck), and small school projects.  This project will be our first tilt-up job. At bid time, we decided to venture into tilt-up work because one of our staff estimator/project managers had extensive experience in tilt-up before he joined our firm. He was experienced enough to win the bid for us. Unfortunately, once COVID hit, he eventually came down with the ailment and is no longer able to work due to severe complications.  That leaves us with an upcoming job on the books with a firm start date and no one currently onboard who has the tilt-up chops to help get the job started. (We understand his counterpart during bid time is no longer with the GC, as well). The project itself consists of a 10,000 square foot (SF) warehouse intended to store winery products and supplies located out in the wine country region. The structural frame consists of 30-foot-tall reinforced concrete tilt-up wall panels with an open-web steel joist roof (no concrete at roof level). The slab on grade is 6 inches thick, placed over 15-mil vapor barrier and 4 inches of drain rock, and reinforced with #4 bars at 16 inches each way. The nominal design compressive concrete strength is 3000 pounds per square inch (psi) at 28 days. Structural typical details indicate 2 inches of concrete cover below sawcut control joints at 1 1/2 inches in depth. There is a small mezzanine located inside the structure, which is supported by a small number of 6-inch square HSS (high strength steel) columns founded on spread footings. The building footprint has an irregular shape, which follows a sharp bend in a local protected creek along two sides of the property.  There is a steep, sloped, 75-foot wide easement that separates the building edge from the bend in the creek bed. No construction vehicles, material storage, or other construction activities are allowed in or on the 75-foot easement.  In other words, there is no available construction access on two sides of the project. Inside the jobsite boundaries, there is virtually no laydown area available. During the kickoff meeting, discussion ensued regarding jobsite access and logistical constraints.  The Owner advised that his office has been contacted by local building officials who reminded him that the environmental restrictions on encroachment--on or into the 75-ft creek easement zone--will be strictly enforced. In addition, the structural engineer advised that driving forklifts or other equipment over the slab on grade or using the slab on grade as a platform for tilt-up panel erection (or structural steel erection cranes) will not be allowed. We had been proceeding with the assumption that we would be able to place the 10,000 SF slab on grade at one time, and then use the new slab as a casting bed for the tilt-up wall panels.  We also assumed our erection crane would be allowed to drive on the slab on grade. The GC advised that a submittal containing our tilt-up panel logistics plan, including crane safety, panel erection, temporary panel bracing and so on will likely have to be approved by the local building official before we can start work, and suggested we get the submittal prepared as soon as possible. We are wondering if the ASCC Hotline can offer any words of encouragement, and hopefully suggest some options to help us meet the challenges described above.  Please advise. Answer: After reviewing the construction drawings for this tilt-up warehouse, we have the following observations and suggestions. --The access constraints and jobsite geometry can easily be found on the contract drawings.  The 75-foot wide easement, for example, appears on multiple sheets. It seems likely that your estimator already had this handled with his counterpart at the GC during pre-bid discussions.  Suggest trying to track that down with a call to the GC. --The compressive strength of the slab on grade (3000 psi) seems to be on the "low" side, which may be driving the engineer's objections to driving equipment on the slab. Since there are ways to strengthen concrete slabs, you may consider a cost-sharing arrangement with the steel erector, whereby costs to re-engineer the slab would be split. Possible options might range from adjusting the mix proportions (e.g. add cement) or perhaps thickening the slab.  Another option might be to call a meeting with the structural engineer, the GC, and the steel erector and ask if a slab analysis/redesign could be handled by his office in-house. Any costs could be covered by a mutually agreed backcharge.  --It may be feasible for you to place the slab in two placements.  Panels would be cast on the new slab, while the crane could stage on the adjacent subgrade and erect the panels from there. --We noticed that there are details that show embedded plates that are shop welded to steel channel sections that serve as ledgers for follow-on framing work at the roof level.  If these assemblies are cast in as designed, you will not be able to stack any tilt-up panels, since the channels protrude past the face of wall.  The assemblies will have to be redesigned such that the ledger channels can be field-welded in place to the embedded portion (placed flush with face of wall) after the walls are erected. Update: The Hotline was just informed that a meeting was held among the Owner, the building officials, and the fire marshal.  It seems likely now that the Owner will have to provide a temporary fire lane along the creek sides of the building. It appears the contractors will be able to use this sanctioned "encroachment" for erection purposes.  It may also be possible that the fire lane will have to be made permanent before the project is turned over. If true, this could help solve most--if not all--of your logistics issues. Note: A pat on the back (and a tip of the hat) goes out to ASCC Technical Committee member Jeremiah Mistele of PROCON, who helped with this Hotline call. Sayde Hindelang Wed, 23 Jul 2025 20:21:00 GMT f1397696-738c-4295-afcd-943feb885714:552 https://ascconline.org/Home/News/articleType/ArticleView/articleId/548/June-2025-Guidance-for-Concrete-Contractors40-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=548 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=548&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/548/June-2025-Guidance-for-Concrete-Contractors40-in-a-Series Jim Klinger, Concrete Construction Specialist The Slab Newsletter June 2025 Full Disclosure: On 18 May 2025, Dr. Ward Malisch--The Original ASCC Hotline Operator--passed away after a long battle with cancer. The following morning, a memorial tribute summarizing and showcasing Ward's extensive concrete industry accomplishments--including his significant contributions to the ASCC--was published in a Message from the Executive Director, see below: "In Memoriam: Dr. Ward R. Malisch (1939–2025) A Pioneer, Mentor, and Lifelong Advocate for ASCC Concrete Contractors The ASCC is deeply saddened to share the news of the passing of Dr. Ward R. Malisch, who died on Sunday, May 18, 2025, in Lebanon, TN, after a courageous battle with cancer. A brilliant engineer, respected educator, and dedicated servant to the concrete construction industry, Ward was a valued member of the ASCC family whose contributions left a lasting mark on our organization and membership. Ward joined the ASCC in 2008 as our first-ever Director of Engineering, a role he held until 2013. He then served as Concrete Construction Specialist until his retirement in 2020. In both roles, Ward was a vital technical resource for ASCC members across the country, translating complex engineering principles into practical, jobsite-ready knowledge that helped members build better and safer concrete projects. Ward’s career began in academia, following BS, MS, and PhD degrees in civil engineering from the University of Illinois. He went on to teach at three universities before joining the American Concrete Institute (ACI), where he served as Director of Engineering and later Senior Managing Director. Ward was an Honorary Member of ACI and an active contributor to several key committees, including ACI 117, 301, and 302, often serving as a bridge between ACI’s technical community and ASCC’s contractor members. Over his lifetime, he authored or coauthored more than 200 articles, books, reports, and papers on subjects of direct importance to ASCC contractors, including tolerances, floors, and specifications. His work consistently addressed real-world challenges faced on jobsites, and he had a rare gift for offering practical, contractor-focused solutions. Ward’s industry honors reflect the breadth of his impact: ASCC Lifetime Achievement Award (2011) ACI Arthur Anderson Award (2010) ACI Construction Award (2011) ACI Roger Corbetta Award (2019) NRMCA Richard Gaynor Award (2008) Construction Writers Association Silver Hard Hat Award (2006) Dr. Malisch wasn’t just a technical expert—he was a mentor, a problem-solver, and a champion of concrete contractors. His voice, insights, and passion for quality construction helped shape the culture and credibility of the ASCC we know it today. He will be deeply missed and long remembered. Our thoughts are with his family and all those in the industry who were fortunate to call him a colleague and friend." I first met Ward at the ACI Fall Convention held in Cincinnati, October 2019-- about a year before retiring from my full-time "day job" and officially joining the staff here with the ASCC Technical Division.  I had decided earlier to sit in as a listener at one of the morning ACI 506 (Shotcrete) Committee Meetings and was just leaving the convention center to grab a bite to eat when I recognized Ward approaching the crosswalk from across the street. There was no way I was going to let him walk by without saying something.    I introduced myself, we shook hands, and I made it a point straightaway to tell Ward how much I (and countless others) have appreciated his work troubleshooting concrete construction for concrete contractors. I advised Ward how his efforts over the years helped me to navigate through many a tough situation-- whether I was working for a private Owner, a structural engineering firm, or a concrete contractor.  It didn't much matter. There are many among the ASCC ranks that have always said the same thing. Ward's valuable concrete troubleshooting advice was brought to bear by many of us almost every step of the way. Since that chance meeting in Cincinnati, I kept in touch with Ward via occasional phone calls and email traffic, the last of which was dated March 3, just a few short months ago. In typical Malisch fashion, Ward downplayed his illness by writing "I am a walking miracle, having entered my fourth year of metastasized bone cancer without any current traumatic pain.  I give God and my faithful spouse all of the credit. Prayer works". Since Ward's passing, I have fielded quite a few Hotline phone calls from ASCC members who wanted to express their condolences and to pay their respects to the Original ASCC Hotline Operator, who will be missed by all of us. _______________________________________________________________________________________________________________ Question: We are considering preparing a bid for a mid-rise (e.g. 5 elevated floors) city government office building that features post-tensioned (PT) concrete slabs. As a company, we have no previous experience with PT work; although we do have a few workers in our reinforcing steel crew that have experience placing and stressing PT tendons.  In addition, one of our carpenter foremen has worked on a small PT garage before hiring on with us. The PT slabs are 8 inches thick, placed with a "high-early" concrete mix that enables stressing to be completed within the specified 72 hours. The mix is designed to reach 3000 psi at 3 days, 5000 psi at 28 days. Our estimators are almost finished with their modeling and take-offs for the concrete and formwork quantities, and the reinforcing steel division is nearing completion of their estimate as well.  The next bid items that need attention include assessment of key baseline schedule activities: structural excavation, concrete placement, and formwork cycling.  We are calling the ASCC Hotline with questions regarding the last item--formwork cycling.  We own enough column and wall forms to do this job, but we are going to have to rent the formwork and shoring for the 5 elevated PT slabs. We invited our carpenter foreman with PT experience to come into the office and meet with our estimating team to discuss the proprietary forming systems currently available for rent in our market; and the labor hours we will need to erect and strip the slabs.  Our foreman advised us that we will not need to reshore the top-most (5th floor) slab once the PT has been stressed and the structural engineer has approved the PT tendon elongation records submitted by the project inspector.  In other words, we will only need to rent the shoring until approximately 5 to 6 working days after the final 5th level concrete placement. (We assume that if we place the slab on a Friday, we will be able to finish stressing the PT by end of the day on Monday.  That leaves 2 to 3 days to strip, clean, and bundle the formwork materials for shipment out on Friday. Hence the 5 to 6 working day duration). Obviously, we wish to return all rented formwork items just as soon as possible after they have been removed, cleaned and bundled.  But despite what our foreman is saying, we just noticed there is a clause in the formwork specifications that states "All formed slabs must be reshored for 30 days". This seems to be a blanket requirement, since it does not distinguish between non-PT and PT slab construction. This is a public works job, and we want to understand the risks. How would you recommend we proceed? Answer:  Good question. This one is slightly complicated because the formwork engineer works for the formwork rental company, which you have not yet hired. One possible way forward, in this case, is to prepare and submit a pre-bid RFI.  Here's why. On most PT projects, the top-most PT concrete slabs do not require reshoring after the PT has been stressed.  (This is something that the formwork designer will have to confirm by calculation after inspecting the construction documents-- particularly the structural drawings--and Division 3 specifications).  The theory is that if the slab concrete can take the PT stressing loads, then--at that point--the slab is its own self-supporting structure, and shoring supports are no longer needed to support the slab. The clause in your specifications described above regarding the requirement for reshores to be placed under all slabs for 30 days is a conservative requirement-- likely based on non-PT slabs-- and probably appears in your specifications due to cut-and-paste by the design team from a previous project. This requirement does not consider the in-situ strength of the concrete--it is based purely on calendar days of shoring in place. The risk to you--both in terms of Safety and in terms of dollars--lies in proceeding with the bid without getting this clarified by the structural engineer. Suggest you submit a pre-bid RFI as follows:  "The project specifications require that all elevated slabs be reshored for 30 days after concrete placement.  Please confirm that this restriction does not apply to the 5th level PT slab." This way, if the engineer is going to enforce the 30-day rule for the upper-most PT slab, all bidders will be informed and can carry the "extra" rental costs to suit.  Another option is to ask the formwork rental bidders to prepare a base quote assuming the rental period ends about a week after the 5th level PT has been stressed as described above. Then ask the formwork rental company to include an "alternate add" line item in their price quote to keep the shoring in place for the extra time--approximately 3 weeks or so of rental. It would also be a good idea to remind your customer that--once you have removed the shoring from the topmost slab areas--dead load deflections and any construction loads placed on the slabs by follow-on trades are not your responsibility. Sayde Hindelang Tue, 17 Jun 2025 19:08:00 GMT f1397696-738c-4295-afcd-943feb885714:548 https://ascconline.org/Home/News/articleType/ArticleView/articleId/547/Potential-Tariff-Impacts-on-Material-Prices#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=547 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=547&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/547/Potential-Tariff-Impacts-on-Material-Prices Mike Hernandez, Technical Director The Slab Newsletter June 2025 ASCC contractors may need to revisit material prices considering recent tariffs, including the 50% tariff on steel announced last month. In the near term, rebar prices have been rising since January. From June 2–9, four major rebar manufacturers raised prices by $60/ton. If bids were submitted this spring and not yet awarded—or if a contract was just sent to your firm—it would be wise to double-check with your rebar fabricator to confirm whether their proposal remains accurate before executing a new contract. Members are reminded of ASCC Position Statement #45: Managing Concrete Projects: Concrete / Steel Price and Volatility Risks, which encourages referencing AIA A201-17 on this topic. It outlines various approaches, including requesting payment for stored materials. The position statement recommends that contractors consult legal counsel to develop or review contract language appropriate for their projects. One possible contract clause might read: “(Client/Contractor/Owner) acknowledges that material prices can fluctuate unexpectedly, and Subcontractor has no control over such material price fluctuations. The subcontractor shall order material quantities for the job and shall be paid for all materials stored for use on the job. Subcontractor shall store materials specifically identified for the job in a manner agreed to by (Client/Contractor/Owner), and all costs of storage shall be reimbursed to Subcontractor as a cost of the work. If Subcontractor material costs increase, then Subcontractor shall be entitled to a change order for these cost increases.” Now more than ever, it’s critical to read contract details carefully and negotiate reasonable terms. Concrete prices should remain mostly unchanged unless you’re ready mixed producer is using imported cement or slag. According to the USGS Mineral Industry Survey, about 20% of the cement used in the U.S. comes from international sources. There are currently nearly 90 cement plants in the U.S., and most are underutilized, either due to unexpected stoppages / down time or a lack of local demand. If your ready mixed producer is citing tariffs as a reason for price increases, it’s worth taking a closer look at what cement is being siloed at your local batch plant. Ready mixed producers know who supplies cement in their market, and there is likely a domestic plant or terminal nearby. If you need help understanding your local cement supply options, ASCC maintains a map of all U.S. cement plants and hundreds of rail terminals, complete with contact information. Google often struggles to distinguish between concrete contractors, ready mixed plants, and cement facilities. Email me at mhernandez@ascconline.org with your city, and I’ll help you better understand your domestic cement options. A substantial amount of formwork systems and overlaid formwork plywood are manufactured internationally. Tariffs likely won’t affect rental rates for existing inventory in the U.S., but it’s worth checking if your formwork supplier is not domestic. Economists have reported that the residential construction market is slowing, and home builders are major consumers of dimensional lumber. The National Association of Home Builders noted on June 6, 2025: “Softwood lumber prices have dropped 4.8% over the past month; however, they remain 12.2% higher than one year ago.” Most softwood lumber imports come from Canada, and as of this writing, the exact percentage of tariffs on Canadian lumber remains unresolved. The market for overlaid formwork plywood like MDO and HDO is more international than dimensional lumber, and trends in this niche market are harder to track. Bottom line: ASCC contractors need excellent communication with formwork, lumber, and plywood suppliers during this unstable time. Engineering News-Record reported last month that overall construction revenue for the Top 400 contractors rose 8% in 2024. However, many are seeing owners cancel or delay project starts “amid confusion over the America First policy,” and interest rates remain high. General contractors are likely seeking more bidders and engaging in more negotiation rounds to keep projects within budget. Know your walk-away number and your schedule. In short, material pricing is unpredictable. Keep communication lines open with clients, key material and equipment suppliers, and consider qualifying your bids with quoted unit prices for major materials. Know the relevant contract language. Where some see challenges, others see opportunity. Hope to see you next month in Carlsbad, CA at CELF. Sayde Hindelang Tue, 17 Jun 2025 19:00:00 GMT f1397696-738c-4295-afcd-943feb885714:547 https://ascconline.org/Home/News/articleType/ArticleView/articleId/546/May-2025-Guidance-for-Concrete-Contractors39-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=546 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=546&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/546/May-2025-Guidance-for-Concrete-Contractors39-in-a-Series Jim Klinger, Concrete Construction Specialist The Slab Newsletter May 2025 Question: We have been asked by the general contractor (GC) to place cementitious slurry backfill in a MEP (mechanical, electrical, plumbing) trench containing a group of 2-inch diameter CPVC (chlorinated polyvinyl chloride) pipes. Our scope of work is to pump, place, and finish cementitious slurry to cover CPVC piping that has been excavated, furnished, and installed by others. The trench dimensions are 2.5 ft. wide, 4 ft. deep, and 130 ft. in length-- which translates roughly into a 49 CY (cubic yard) placement. The construction documents present the typical requirements for backfill at MEP trenches as follows: In addition to the above stated backfill requirements, the following review comments were extracted from the approved CPVC material submittal prepared by the MEP subcontractor and forwarded to us by the GC: "Contractor to submit backfill mixture that limits heat of hydration to less than 220 degrees F.  Submit records that document--during backfill and curing--that the temperature remains below 220 degrees F.  If temperatures reach or exceed 220 degrees F, piping must be removed and replaced". Following the above criteria, our readymix supplier prepared a mix design for submittal titled "2-Sack Sand Slurry" with the following per-cubic-yard proportions:  Type II/V cement: 188 pounds. Water: 517 pounds (62 gallons). Sand: 2803 pounds.  Total weight per cubic yard:  3508 pounds.  Unit weight:  130 pounds per cubic foot (pcf). Slump: 5 inches, plus or minus 2 inches. No admixtures were specified or included. Unfortunately, our readymix supplier is unable to find on file any historical data (thermal or compressive strength performance) to furnish as backup for their 2-sack sand slurry mix. So we attempted--on our own--to find documentation that would help us predict the maximum heat of hydration for the proposed mix.  It turns out that the available concrete industry thermal formulas and models all seem to be based on mixes with much more cement content than ours; and with larger concrete member dimensions than ours. Put another way, it turns out that our proposed slurry mix is too lean-- and the trench is too small--to be considered "mass concrete"--and therefore cannot be considered as a realistic cause for concern. At this point, the questions then became:  "Given our cementitious slurry mix containing 188 pounds of Type II/V cement per cubic yard, what would the thermal performance likely to be during the first few days after initial placement of the slurry? How long will it take for the in-place slurry to attain maximum temperature after placement? After much research and in-house, jobsite trailer debate, we advised the project Owner that it is not possible for the proposed 2-sack slurry to reach a temperature of 220 degrees F during the curing period. In fact, we actually anticipate the curing temperatures to be well under 100 degrees F.  We are looking to the ASCC Hotline to take the temperature of this situation and weigh in. Answer: Interesting question. As concrete contractors, the Hotline doesn't field many questions like this, since backfilling of MEP trenches is typically performed by others before our members mobilize onsite and take ownership of the prepared building pad. Nevertheless, this scenario highlights risks associated with incidental concrete work that ASCC members may eventually be asked to take on. Consistent with the ASCC Hotline's long-standing M.O. (modus operandi), we typically recommend Hotline callers try to have a look at the other guy's playbook. After all, according to the CVPC pipe supplier's stated upper limit of 220 degrees F, the backfill slurry could be at the boiling point of water after placement and still be acceptable (water boils at 212 degrees F), with 8 degrees F to spare.   We began our playbook literature survey by reviewing a technical brief prepared by the PVC Pipe Association titled "PVC Pipe In Contact With Concrete" and dated 7 May 2021, which explains: "During the concrete curing process, heat is generated (known as "heat of hydration"). The vast majority of installations experience no issues with excessive heating.  If this is a concern, choosing concrete formulations with low heat of hydration is the most common solution.  Another option is to dissipate heat by filling the pipe with water (essentially creating a heat sink) until the concrete has cured."  A similar Technical Bulletin found in an industry pipe manufacturer's playbook  titled "Best Practices for Concrete Encasement of PVC and CPVC" addresses potential topics such as how to prevent flotation of PVC pipes during placement of concrete, why it is best to limit the maximum depth of cover over the pipes to 2 feet, and preventing damage that might be caused to the pipes by mechanical vibrators during slurry placement. Regarding potential thermal damage, the Technical Bulletin offers the following guidance: "During the curing process of the concrete, temperatures within the concrete may very well rise above the ambient temperature conditions.  Care should be taken to prevent the piping system from experiencing temperatures above 140 degrees F. Although the idea of blowing cold air through the piping system might achieve the required temperature control, another option is to consider filling the piping system with cold water. The cold water would act as a thermal heat sink." In the course of our literature review, we found an industry report describing potential heat of hydration issues associated with lightweight cellular concrete (LCC) used in certain backfill applications. A recent Portland Cement Association document (Guide to Lightweight Cellular Concrete for Geotechnical Applications, January 2021) reports the following: "LCC is comprised of portland cement, water, and air (added through a preformed foaming agent). The curing of cement is an exothermic reaction, commonly known as the heat of hydration.  This rapidly occurring chemical reaction has been known to generate temperatures above the boiling point of water.  Under normal conditions, the heat of hydration in an LCC fill begins two to four hours after placement...The heat of hydration can be a significant problem when placing plastic pipes within large masses of LCC undergoing curing and should always be considered when designing an LCC fill.  While an LCC fill will always warm up, placement with an open top will not obtain the maximum heat forecasted, which assumes no heat loss and represents the highest temperatures possible.  Internal temperatures in large flat fills typically range from 100 to 150 degrees F."  Based on the above, we can see why the CPVC pipe supplier would raise the issue of potential damage caused by cementitious heat of hydration. Next step: we have the approved mix design for the slurry in hand, but the readymix supplier lacks any historical temperature performance data for us to use as backup. Where do we go from here? Following the Hotline caller's lead, we searched the ASCC Technical Division library facilities for information that might help us predict (and monitor) the heat of hydration for a lean slurry backfill mixture. The closest information we could find was all related to American Concrete Institute (ACI) and other industry publications that discuss mass concrete and describe preparation of thermal plans typically required for projects featuring mass concrete. Out of all the documents and articles that we located, perhaps the best suited for our purposes is a PCA publication titled "Engineering Mass Concrete Structures", part of the Professional Development Series for continuing education. Authored by John Gajda and Ed Alsamsam, this 2006 publication offers the following guidance that explains one easy way to predict concrete temperatures: Based on the procedure described above, the ECC factor for the trench backfill turns out to be the same as the actual cement content, which--in our case--is 188 pounds per cubic yard. The predicted rise in temperature, then, is calculated by multiplying the ECC by 0.14 as described above--which results in a temperature rise of 26.32 degrees F (rounded down to 26 degrees F). The next step is to add the expected temperature rise to the temperature of the concrete as delivered.  If we assume the temperature of the slurry at delivery is 75 degrees F, then the maximum predicted temperature would be the sum of 26 plus 75, or a total of 101 degrees F-maximum. (N.B.: The ECC factor for "straight" cement is reckoned in the above PCA procedure on a 1-to-1 basis. Fly ashes and slag, on the other hand, contribute less to the heat generated by the mass, so their respective ECC factors are reduced to suit. The lowest ECC factor presented above is for Class "F" fly ash-at 0.5 percent-a pozzolan popular in concrete mixes that offer reduced short-term heat of hydration in exchange for slower, long-term time needed to reach design compressive strength. We have experience with at least one successful foundation mat slab mix featuring Class F fly ash that was designed to reach the required compressive strength at 120 days). Keep in mind that the PCA method presented above is valid for concrete with certain minimum dimensions and a certain minimum cement content per cubic yard. As reported by the Hotline caller and described above, the proposed slurry mixture is so lean--and the dimensions of the trench are so small--that we find ourselves outside of the extreme lower limits of what could reasonably be considered mass concrete. In any event, it seems fair to say that the 101-degree F temperature calculated above falls on the conservative side, and very close to the "well under 100 degrees F" temperature advertised by the Hotline caller to the project stakeholders. JOBSITE UPDATE: As scheduled, the slurry backfill was placed last weekend, with placement starting at 1:30 AM.  The slurry was placed with a trailer pump featuring 50 feet of rubber hose "system". Temperature sensors were placed in the slurry at three locations along the MEP trench; each sensor was located 4 inches below top of slurry elevation. According to the reports generated by each of the three sensors, the average slurry temperature at delivery was 61 degrees F. The average maximum temperature inside the slurry mass--at an average of 16 hours after placement-- was measured at an average of 76 degrees F. Using the PCA formula described above, and using a temperature at delivery of 61 degrees F, the result predicts a maximum temperature of almost 86 degrees F; which--given the lean mix and small sample size--a conservative answer is no surprise. Sayde Hindelang Mon, 19 May 2025 21:44:00 GMT f1397696-738c-4295-afcd-943feb885714:546 https://ascconline.org/Home/News/articleType/ArticleView/articleId/545/A-Culture-of-Quality#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=545 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=545&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/545/A-Culture-of-Quality Mike Hernandez, Technical Director The Voice Newsletter May 2025 Several weeks while attending the Annual Conference of the Design & Construction Excellence Exchange (The DCX) it hit me that ASCC Contractors should strive for a Culture of Quality like the Culture of Safety has been developed for the last few decades. Why? Let’s start with safety. Surprisingly, two ENR top 20 contractors in the DCX reported that their craft workers are 3x to 14x more likely to be injured performing quality rework than on first time base contract scope. They intently plan the base contract scope and all too often the craft are left to figure out rework. Beyond safety, quality issues also cost extra money, impact company reputation and often schedule, a quadruple whammy. One of the best tools are company and project specific Quality Plans & scope specific Work Plans. Kiewit & Archer Western in the transportation sector, PCL & Mortenson in buildings have work plans for specific elements of self-performed concrete work or they ask the concrete specialty contractor to generate them. Work plans break each scope, for example tilt panels, into a step-by-step procedure which ideally is one or two 11x17 pages with multiple appendix references for everything from construction chemicals to lifting equipment product data. Many contractors print them in English on one side, in Spanish on the other side. U.S. Army Corps of Engineers has the gold standard for training quality personnel on setting up and executing a quality plan. They focus on “distinguishable elements of work”. Those could be shear walls & columns, elevated decks. Or more general like placing & finishing. A 2019 survey of ASCC Members stated that quality challenges with drawing quality is among the biggest concerns among the membership. This is in part because experienced engineers are retiring, designers have less time and fee to put into proper coordination. BIM / VDC continues to gain market share as a solution to poor drawing quality. ASCC Members Pinnacle Infotech, Zenith BIM Services & MB Solutions, a subsidiary of GH Phipps can provide BIM/VDC support services. See websites: https://pinnacleinfotech.com/ ,  https://zenithbim.com/ , https://www.mbbimsolutions.com/ Many members have reported that sustainably has increased the level of difficulty of concrete operations. It is easier for engineers to skinny a structure by introducing more column sizes and more beam sizes because the software can handle it. Form work quantities and labor increase to save a few cubic feet of concrete. Lower clinker content can make placing & finishing more challenging. Simultaneously multiple companies market AI as a tool to lower over design in ready mixed concrete. Testing labs may exclude initial curing tanks causing low breaks to be more frequent.  Solutions? The ACI Pro Constructability Blueprint has been developed to help designers make their projects more productive. Establish a relationship with local cement and ready mixed technical staff. ASCC can help you figure out who that is. Purchase ready mixed concrete on quality & consistency instead of only on lowest price. Last month we highlighted the CRMCA CTAC program to help with testing lab consistency and meeting ASTM C31 initial curing standards. Placing concrete has a lot of inherent variability. Look for opportunities to create consistency for finishers by using the same mix proportions project to projects. Ask for feedback from finishers about what can be improved in those mixes. Give the place and finish team FF/FL feedback with your own E1155 device to increase consistency and reduce the risk of follow-on trade complaints. Formwork standard operating procedures will continue to increase in importance because of a shortage of skilled labor with highly experienced craft retiring. BIM coupled with virtual reality is one way to train on form work systems. ASCC Members Doka & Meva have libraries of BIM formwork components. Can go all in with virtual reality such as the “Build the Future” VR tech highlighted by ASCC in our 2025 World of Concrete booth.   The potential to save money, improve reputation, and work safer is all there in shifting to a culture that focuses on quality. Any company that makes this transition has a bright future. Sayde Hindelang Mon, 19 May 2025 21:40:00 GMT f1397696-738c-4295-afcd-943feb885714:545 https://ascconline.org/Home/News/articleType/ArticleView/articleId/532/Welcome-Chris-Sullivan-Back-as-the-DCC-and-CPC-Programs-Director#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=532 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=532&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/532/Welcome-Chris-Sullivan-Back-as-the-DCC-and-CPC-Programs-Director ST. LOUIS, MO – April 14, 2025 – ST. LOUIS, MO – The Decorative Concrete Council and the Concrete Polishing Council of the American Society of Concrete Contractors are excited to welcome Chris Sullivan back as the DCC and CPC Programs Director! Chris is widely recognized as a leading expert in the decorative concrete industry, with a career spanning over two decades focused on troubleshooting, technical excellence, and education. Known for his deep expertise in sealers, color systems, and surface performance, Chris has been a sought-after speaker and trusted voice in the field since 2005. He has presented at major industry events, including the World of Concrete (since 2004) and the Concrete Decor Show (since 2009), and contributed to dozens of other conferences and symposiums worldwide. His written work has appeared in industry-leading publications such as Concrete Expressions, Durability and Design, Concrete Homes, Concrete Décor, and Concrete Products. His popular “Concrete Questions” column in Concrete Decor magazine ran for over a decade, and his technical forum on Concretenetwork.com continues to serve as a go-to resource. Chris has authored over 200 articles and four books on trends, troubleshooting, and best practices in decorative concrete. In recognition of his impact, he was inducted into the Decorative Concrete Hall of Fame in 2015. Chris previously served as ASCC’s Decorative Concrete Specialist from 2019–2022, where his contributions were instrumental in elevating technical support and educational resources for our members. He is also a technical consultant for Bomanite International, an ACI-certified examiner, and—remarkably—a living kidney donor, having made an altruistic donation in 2020. Chris holds a B.S. in Chemistry from the University of Pittsburgh and currently lives in Denver, Colorado, with his family. He is also the Senior Vice President of Sales for Painters USA, the largest woman-owned industrial services contractor in the country. We’re thrilled to have Chris back on the ASCC team and look forward to the innovation, leadership, and expertise he brings to the Decorative Concrete Council (DCC) and Concrete Polishing Council (CPC), according to Ray Hefner, CAE, Executive Director. The Decorative Concrete Council (DCC): The Decorative Concrete Council (DCC) is a specialty council of the American Society of Concrete Contractors (ASCC) dedicated to promoting excellence and innovation in decorative concrete. Through education, advocacy, and networking opportunities, the DCC supports professionals in the decorative concrete industry and advances the artistry and craftsmanship of decorative concrete worldwide. The Concrete Polishing Council (CPC), a member group of the American Society of Concrete Contractors (ASCC), was established to provide industry standards, education, and a professional network for polishing contractors and others working in the polished concrete sector. As part of the ASCC, the CPC's primary goals are to offer training opportunities and certification programs for its members, while also serving as a resource for best practices and technical guidance to the broader design and construction community. The American Society of Concrete Contractors is a non-profit organization dedicated to enhancing the capabilities of those who build with concrete and to providing them a unified voice in the construction industry. Members include concrete contracting firms, manufacturers, suppliers, and others interested in the concrete industry, such as architects, specifiers, and distributors. There are approximately 710 member companies in the United States and abroad. For more information, visit www.ascconline.org or call the ASCC office at (866) 788-2722. For more information, contact: G. Raymond Hefner, CAE Executive Director 314-962-0210 rhefner@ascconline.org Sayde Hindelang Wed, 30 Apr 2025 21:15:00 GMT f1397696-738c-4295-afcd-943feb885714:532 https://ascconline.org/Home/News/articleType/ArticleView/articleId/531/April-2025-Guidance-for-Concrete-Contractors38-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=531 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=531&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/531/April-2025-Guidance-for-Concrete-Contractors38-in-a-Series Jim Klinger, Concrete Construction Specialist The Slab Newsletter April 2025 Question: We are building a 4-story, post-tensioned (PT) concrete parking structure that has a footprint area of 75,000 gross square feet (GSF). The structure has a long, rectangular aspect ratio (in plan), featuring entrance/exit ramps at each end. The plan dimensions are 600 linear feet (LF) in length and 125 LF in width. Since the PT structure is expected to shorten due to the application of PT forces, and would be susceptible to thermally induced movements (e.g. expansion and contraction) due to its length, an expansion joint was placed by the structural engineer which bisects the structure into two equal 300 LF sections. For all practical purposes, introduction of the expansion joint results in two separate buildings; each with plan dimensions of 300 LF long by 125 LF wide. The specified concrete compressive strength is 3000 psi at 3 days (for PT stressing purposes) and 5000 psi at 28 days. All the ready-mix suppliers in our area have developed similar, off-the-shelf mixes to satisfy these so-called "high-early" compressive strength performance requirements.            There are two floor finishes specified for the 8-inch-thick PT slabs; namely a trowel finish in small areas in front of the elevator bank and in mechanical rooms, and a swirl finish for the balance of the work, including drive lanes, parking stalls, and ramps.  And speaking of ramps, that is why we are calling the ASCC Hotline. The ramps in this garage are 30 feet wide. Since the "high-early" concrete has performed as advertised, our PT stressing operations have been both efficient and uneventful--until our stressing crew pulls the short tendons at the ramps.  We can't seem to get the 30-foot tendons to elongate within the allowable tolerance of plus/minus 7 percent of the theoretical elongation--as calculated by our PT supplier--and included in our (now approved) PT shop drawing submittal.  For example, the theoretical elongation should be around 2 3/8 inches. We are averaging measured elongations of say 2 3/16 inches. On this project, the structural engineer of record only provided the required tendon forces on the floor plans (aka required effective force, after all losses). From those plans, it was then our responsibility to hire a licensed engineer to calculate the number of unbonded PT tendons (e.g. uniform, banded, temperature) needed to supply the engineer's required effective forces; and then provide supporting calculations that indicate the theoretical lengths that each tendon should elongate to when stressed to the appropriate jacking force.  When completed, the PT submittal had to be reviewed and approved not only by the structural engineer--but by the City Building Department plan check engineer as well. In our experience, we have built several PT garages with ramps, and have never had problems with the short tendon pulls. According to our project specifications, we cannot cut the stressed tendon tails and complete the corrosion protective encapsulation system (e.g. "cut--grease--cap--grout") until the PT elongation records have been approved. We understand the tendon finishing activities are important, but that work--along the ramp slab edges--is not on the project critical path. On the other hand, removing the false work supporting the ramps and cycling the formwork to the upper floors is on the critical path.  Once the tightly spaced ramp falsework is replaced with reshores, we can gain access to move materials up and down the ramp--typically accomplished with push carts (aka "cadillacs"). In other words, the project can suffer delays when the approval process that triggers formwork cycling is slowed or stopped while the short tendon elongations are investigated by both the PT supplier and the structural engineer, which is what is happening now.  The PT supplier is checking the calibration scenario and is running friction calculations; the structural engineer has been contacted, but has yet to weigh in.  We are expecting the engineer to ask us to perform a few "lift-offs" (e.g. re-pull certain tendons until the wedges release, then read gauge pressure on the ram to verify forces in the tendons) and report our findings. We are looking for guidance from the ASCC Hotline to help us work through this, and to find out if there is a better (and faster) way to resolve short tendon pulls.  Please advise. Answer: You are not alone. Over the years, the ASCC Technical Division has fielded calls from members who have reported that "when it comes to PT... short tendons never seem to come up".  As it turns out, there is plenty of industry documentation that describes the problem of short tendon elongations--and possible reasons why--and some solutions. Let's start with the ACI Code. According to the approved PT calculations prepared by your PT supplier, the 30-foot-long ramp tendons have a theoretical measured elongation of 2.37 inches--or approximately 2 3/8 inches.  According to the ACI Code (e.g. ACI 318-19 Building Code Requirements for Structural Concrete) section 26.10.2(e), there are two ways the prestressing force shall be verified: by measured tendon tail elongation, and by the jacking force measured with the gauge of a calibrated stressing ram.  For a theoretical measured tendon elongation of 2.37 inches, the 7 percent tolerance is roughly 3/16 inch.  The actual gauge pressure will be given by the calibration charts and other equipment documentation that should have accompanied the stressing ram when it was sent to the jobsite. ACI Code section 26.10.2(f) states "The cause of any difference in force determination...that exceeds 5 percent for pretensioned construction or 7 percent for post-tensioned construction shall be ascertained and corrected, unless approved by the licensed design professional". Why is the tolerance more "relaxed" for the post-tensioned construction as opposed to pretensioned construction?  The answer is given in corresponding Code Commentary section R26.10.2(f) as follows: "The 5 percent tolerance for pretensioned construction reflects experience with production of those members. Because prestressing reinforcement for pretensioned construction is usually stressed in air with minimal friction effects, a 5 percent tolerance is considered reasonable. For post-tensioned construction, a slightly higher tolerance is permitted. Elongation measurements for post-tensioned construction are affected by several factors that are less significant or that do not exist for pretensioned construction.  The friction along prestressing reinforcement in post-tensioning applications may be affected to varying degrees by placing tolerances and small irregularities in tendon profile due to tendon and concrete placement.  The friction coefficients between the prestressing reinforcement and the duct are also subject to variation". Another document that explains the short tendon syndrome comes to us from the Post-Tensioning Institute (PTI) Special Topics Committee.  Titled "Short Tendon Elongations, PTI Technical Note No. 16" offers a comprehensive review of the topic, and offers some suggested solutions--including relaxing the tolerances. A link to the PTI Tech Note 16 is here: https://www.post-tensioning.org/Portals/13/Files/Pdfs/Education/Technical%20Note%2016.pdf In similar fashion, another PTI publication prepared by the PTI Unbonded Tendons Committee called "Frequently Asked Questions: Field Elongation Measurements" offers a thorough explanation of best practices for addressing short tendon pulls. A link to PTI FAQ No. 6 is here: https://www.post-tensioning.org/Portals/13/Files/pdfs/Education/FAQ%20no.%206.pdf As luck would have it, a recent issue (March 2025) of "Structure" Magazine contains an article titled "Best Practices for Post-Tensioning Elongation Records", which has been approved for reprint by the Post-Tensioning Institute (PTI). A link to the article is here: https://www.structuremag.org/article/best-practices-for-post-tensioning-elongation-records/ Here's an excerpt from the "Structure" article regarding the issue of short tendon elongations: In order to resolve your particular issue, we briefly reviewed your plans, specifications, PT shop drawings, and calculations approved for project use.  As it turns out, the construction team (including the project inspector) appears to have overlooked the tolerance specified in the structural General Note 18.10 that will give you some relief--an allowable tolerance of plus/minus 10 percent.  See below: Once you read the technical information via the links given above, you will see that--in addition to lift-offs and additional computer runs--the most sensible course of action is to apply a little engineering judgement and relax the tolerances.  This appears to be what your engineer has done by moving the tolerances 3 points in each direction--to plus/minus 10 percent from 7 percent. Sayde Hindelang Wed, 30 Apr 2025 19:51:00 GMT f1397696-738c-4295-afcd-943feb885714:531 https://ascconline.org/Home/News/articleType/ArticleView/articleId/530/CTAC-Overcoming-Concrete-Testing-Challenges-for-Project-Success#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=530 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=530&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/530/CTAC-Overcoming-Concrete-Testing-Challenges-for-Project-Success JT Mesite, P.E., CRMCA & CTAC Program Manager Edited by Mike Hernandez, ASCC Technical Director Concrete construction is an intricte process where quality control is paramount. Field testing must continuously meet specific ASTM requirements, and project concrete depends on maintaining precise temperature controls, effective initial curing processes, and a clear understanding of roles. The 2024 data indicates that ~80% of commercial projects do not meet all the ASTM standards for making and curing test clyinders. In most cases, testing and specimen evaluation are critical for quality assurance; they confirm that the material supplied by the concrete producer arrives on-site exactly as ordered and specified by the mix design. However, achieving this consistency is challenging. Variability in testing procedures, curing facilities, and monitoring conditions, as well as fragmented communication among project stakeholders, can lead to discrepancies that ultimately affect a project’s success. The Colorado Ready Mixed Concrete Association (CRMCA) and ASCC have entered a collaboration to support proper concrete testing. If you prefer to listen to a summary of the CTAC solution, Todd Ohlheiser, CRMCA Executive Director, was recently interviewed on the Concrete Logic Podcast, posted to YouTube: https://youtu.be/FwtwkV32KGY The Project-Level Challenges Every construction site faces the critical task of ensuring that concrete samples and testing adhere consistently to ASTM requirements. Field testing isn’t just a formality, it is the backbone of a project’s quality assurance. One of the most important phases is the initial curing process, which is essential for long-term strength and durability. In many projects, specimens undergo either a standard cure or a field cure. Standard cure is focused on verifying the concrete’s quality per the mix design, while field cure is generally applied when removing forms or opening areas for traffic. Often, inadequate temperature control and facility limitations during standard curing can compromise the process and is the most frequenelty violated early test. The specifications outlined in ACI 301 and ACI 318 place a shared responsibility on all parties involved, demanding continuous oversight and proactive communication. When pre-construction meetings and regular team discussions fail to bridge the gap between planning and on-site realities, delays, rework, and compromised structural integrity can result. Empowering On-Site Teams with the CTAC App Enter the Concrete Testing Adherence Collaboration (CTAC) program, a comprehensive solution designed to address these challenges. CTAC brings together observation, review, and reporting tools into a single platform, providing the ability to collect observation data into a collective dashboard. This actionable data not only improves testing consistency but also fosters ongoing dialogue among team members throughout every phase of a project. Observation: Capturing Critical Data in Real Time The observation module is the foundation of CTAC, empowering field personnel to capture vital testing data as conditions unfold on-site using the CTAC phone app. Key features include: GPS Integration and Offline Capability: Every observation is accurately geotagged and securely saved, even in areas with unreliable internet connectivity. User-Friendly Interface: The interface simplifies data entry so that every Observer, certified as an ACI Concrete Field Testing Technician Grade I, can efficiently record essential metrics consistently. It also allows the observer to note any inconsistencies while the testing technician performs procedures and capture supporting photos or short videos, ensuring immediate, open communication on-site. Daily Initial Curing Checklist: Perhaps the most transformative feature is the initial curing review module, which is the most often violated ASTM standard based upon thousands of observetions and can negatively effect cylinder strength by up to 20%. Unlike the more complex field-testing observations that require ACI certification, this tool serves as a daily checklist item that any trained contractor can use. By routinely verifying that initial curing conditions meet ASTM standards, teams can identify potential issues early, sparking timely conversations during construction meetings or daily briefings that keep every stakeholder informed. The training process involves watching a ~ 5 minute video and answering a 6 question test to confirm understanding. Review: Validating Data and Enhancing Training Once data is captured, the review module acts as a vital quality checkpoint where project leaders can assess performance, address issues, and celebrate outstanding teamwork: Data Validation and Error Flagging: Supervisors can quickly verify observations, with the system automatically highlighting inconsistencies that warrant further attention. Enhanced Training Opportunities: Feedback from the review phase has spurred the development of specialized training modules, particularly focusing on improving initial curing practices. Although observations collected in the past two years show that only about 20% of samples meet the ideal curing conditions, this statistic is viewed as an opportunity to refine techniques and boost overall quality. Seamless Integration: The review process works in tandem with the observation and reporting tools, ensuring a smooth flow of information that supports continuous learning and encourages ongoing discussions among team members. Reporting: Turning Data into Strategic Insights The reporting module transforms raw data into actionable insights that drive better decision-making: Customizable Dashboards: Project managers and stakeholders can generate reports tailored to specific needs, whether for daily operations, project reviews, or high-level strategic planning. Real-Time Access: Up-to-date information is readily available, empowering teams to address issues proactively and maintain project momentum. Scalable Insights: From monitoring individual projects or employees to assessing regional or nationwide trends, the reporting tool provides a comprehensive view that supports both immediate improvements and long-term planning. These insights serve as conversation starters during team meetings, pre-construction reviews, and strategy sessions, further embedding open communication into the project workflow. Addressing Adoption Challenges and Shaping the Future Despite its many advantages, the CTAC app has faced its share of hurdles. Early on, some testing firms misconstrued CTAC as a surveillance tool rather than a collaborative platform for quality improvement, which created resistance among certain entities. However, through ongoing dialogue and the sharing of success stories, often discussed during regular project meetings, perceptions are shifting. Contractors are increasingly recognizing CTAC for its true value in enhancing communication and bolstering quality control on-site. The onboarding process initially presented its own set of challenges, with users needing time to adjust to the new system. In response, CTAC is overhauling its training resources. Each module now provides clear guidance on using the observation, review, and reporting features, ensuring that even newcomers can quickly become proficient. This educational focus is particularly vital in reinforcing the daily use of the initial curing review as a simple yet effective tool to safeguard concrete quality while keeping the lines of communication open among all team members. A Vision for Nationwide Impact Looking ahead, CTAC is poised to revolutionize concrete testing on every scale, from single projects to regional and ultimately nationwide operations. Recent changes, such as the shift from Partner-based to Company-based logins, aim to streamline data submission and broaden access, with users across the country contributing to a centralized database of nearly 2,500 field observations in the past 12 months. Continued Collaboration We invite every ASCC contractor to participate that works in a state who has joined the CTAC program (AL, CA, CO, GA, IA, MN, ND, TX, WA, WI & Ontatio Canada) which represent ~ 40% of the U.S. population. ASCC Contractors can join as a full observer if they have current ACI Concrete Field Testing Technican Certification. To request Observer access to the CTAC program scroll to the bottom of the page here: https://www.concretetac.com/member-login/ and fill out the form. The other option is to watch one ~ 5 minute video plus a 6 question exam to become an Initial Curing Reviewer. If you want to become an IC reviewer folow this link and click on “Start now”: https://forms.office.com/pages/responsepage.aspx?id=l21lIvFqD0yCep-tIjfx2wq9PHc1nkxCrQ5gGJnk4_RUNzJOWUZHRDJBQ0NVT1JZWkZYSVhGR1VYWiQlQCN0PWcu&route=shorturl For further information, assistance, or to share your feedback, please contact us at ctac@coloradocaa.org or visit our website at www.concretetac.com. Your participation is the key to our collective success in transforming the industry. Sayde Hindelang Wed, 30 Apr 2025 19:43:00 GMT f1397696-738c-4295-afcd-943feb885714:530 https://ascconline.org/Home/News/articleType/ArticleView/articleId/529/A-Message-from-the-Board-of-Directors#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=529 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=529&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/529/A-Message-from-the-Board-of-Directors Greg Hryniewicz, Vice President Observant Leadership In the demanding world of concrete, our workforce is diverse in skill and personality. For many of us leaders, our primary role is optimizing our team’s productivity. One strategy I have been working on is observing and understanding my employees. Observation is a deceptively simple yet powerful tool. By watching how individuals perform their tasks, interact with peers, and talk about their interests, I gather valuable insights into their strengths and weaknesses. This goes beyond merely identifying who is efficient at processing invoices or preparing schedules; it encompasses understanding their interests, communication styles, leadership potential and work bias. For example, an administrative assistant who consistently resolves scheduling conflicts or proactively organizes data might have strong analytical and organizational skills. Similarly, an employee who frequently expresses creative opinions might not be best suited for rote tasks. Leveraging Personality Profile Tools While observation provides qualitative insights, personality profile tools add a layer of quantitative assessment. Instruments like the DISC personality assessment or the Myers-Briggs Type Indicator can reveal underlying tendencies that are not always apparent on the surface. These tools help categorize individuals into actionable profiles—such as those who are more creative vs those who ‘just want to get it done’. When used more broadly, you can see if you have gaps in your organization, identifying unseen weaknesses. Implementing these assessments need not be complex. An initial investment in training or hiring a consultant to administer and interpret the results can yield long-term benefits. These tools not definitive judgments but guides to better understanding their team and the players. Evaluating and Matching Skills to Roles Once armed with observational insights and personality profile data, the next step is ensure employees are in a position to succeed. For instance, consider an employee who demonstrates a keen eye for design but struggles with multitasking under tight deadlines. Assigning them to roles that prioritize creativity, like client relations, may yield better results than expecting them to manage multiple projects. Conversely, a dynamic individual might thrive in roles like project coordination, where hustle, agility and quick thinking are essential. Building a Culture of Cooperation Understanding and leveraging individual strengths also fosters cooperation. When employees recognize that their unique contributions are acknowledged and valued, they are more likely to respect and support their peers. This creates a workplace culture where collaboration is the norm rather than the exception. The Role of a Leader Ultimately, an observant leader acts as both a leader and a strategist, guiding their team to function as a cohesive unit. By combining the art of observation with the science of personality profiling, leaders can unlock their team’s full potential. The result is a workforce that exceeds operational goals. In concrete, the true foundation of success lies in the strength of the team. Invest the time to understand your employees as a whole, and you’ll build more than just structures—you’ll build a legacy of excellence. Sayde Hindelang Wed, 30 Apr 2025 18:10:00 GMT f1397696-738c-4295-afcd-943feb885714:529 https://ascconline.org/Home/News/articleType/ArticleView/articleId/523/Influence-the-ACI-Guides-Manuals-Standards#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=523 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=523&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/523/Influence-the-ACI-Guides-Manuals-Standards Mike Hernandez, Technical Director The Voice Newsletter March 2025 Have you ever been frustrated by what was included or not mentioned in an ACI document? If so, you are not alone which is why numerous contractors, material suppliers, ready mixed producers, engineers and university professors have engaged in the ACI document creation and editing process. As of January of 2025, ASCC Contractors and Associate members are officers and/or voting members on 82 ACI committees. The topics can be Technical such as 302 Construction of Concrete Floors and 544 Fiber Reinforced Concrete, generically the 100 – 500 series committees. There are Educational, the E committees, for example E703 Concrete Construction Practice, responsible for the joint ACI-ASCC Contractor’s Guide to Quality Concrete Construction, with over 90,000 copies sold. Committees can focus on Certification, the C Committees, like C640 Craftsman Certification, responsible for ACI Flatwork Finisher and C641 Decorative Concrete Finisher Certification Committee. The upcoming ACI Convention will be held in Toronto, ON Canada March 30th – April 2nd. The fall Convention will be October 26th-29th, 2025 in Baltimore, MD. There are sure to be 100+ ASCC member representatives at both of them. Considering joining us and getting involved to provide the contractors’ perspective on more documents. There are presentations, student competitions, lunches and receptions as well at every convention if editing documents is not your thing. ACI committee membership can change at any time, as the Chair has the flexibility to add voting members or remove someone’s voting status due to non-participation. Every ACI International member is allowed to become an Associate (non-voting) Member of up to 3 ACI Committees to keep up with their activities. Becoming a voting member usually involves attending several ACI Convention committee meetings and volunteering to assist on committee work, either editing or presentations or authoring new documents. With over 100 committees, there are lots of options for most every interest. Among the committees are several super committees that are by invitation, such as ACI 318 Structural Concrete Building Code and 301 Specifications for Concrete Construction, with 41 voting members and 49 subcommittee members organized in 17 subcommittees.  All ACI Board Committees, those with numbers below 100, are also by invitation. ASCC Members that volunteer as Voting members of ACI Committees: By Popularity, High to Low                                                                                                                                          ASCC Voters If you are interested in participating and unsure how to start, send me an e-mail at mhernandez@ascconline.org so we can consider some options from residential concrete to tilt-up to bridges and everything in between. ASCC probably has a voting member or an associate member that will be there too and ASCC staff can make an introduction.    Sayde Hindelang Fri, 14 Mar 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:523 https://ascconline.org/Home/News/articleType/ArticleView/articleId/524/March-2025-Guidance-for-Concrete-Contractors37-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=524 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=524&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/524/March-2025-Guidance-for-Concrete-Contractors37-in-a-Series Jim Klinger, Concrete Construction Specialist The Voice Newsletter March 2025 Question: Two weeks ago, we kicked off the structural excavation, formwork erection, reinforcing steel placement, and concrete placement activities for the foundation supporting a 6-story post-tensioned (PT) parking garage located south of San Francisco airport (SFO). The garage is intended to provide 1540 parking spaces on a total floor area of 552,000 gross square feet. Suboptimal soil conditions (e.g. San Francisco "Bay Mud", typically found in the marginal coastland surrounding San Francisco Bay--the so-called "Bay Margin") documented in the project geotechnical report prompted the structural engineer to design a foundation consisting of driven prestressed concrete piles and a network of reinforced concrete pile caps and grade beams. In similar fashion, the worst-case expected soils conditions caused the slab at grade level to be designed as a self-supported, elevated structural slab--10 inches thick-- with top and bottom layers of reinforcing steel. (N.B.: The geotechnical report is unusually replete with warnings contained in a special, 4 page report supplement (aka "Appendix D") aimed at prospective bidders that describes the known risks associated with Bay Mud and the potential hazards that are likely to be encountered; not only by the mass earthwork contractors-- but by follow-on contractors as well--including shoring, foundation, waterproofing, utility, and even the landscape trades. The introduction to the appendix containing the guidelines appears as follows: At the conclusion of the appendix, the following summary caveat to bidders and other stakeholders appears thusly: In addition to the above, the Owner-Developer distributed similar "Instruction to Bidders" documents before bid time that advertised aggressive --but reasonably achievable-- schedule expectations. One such bid instruction was a reminder to bidders that--even though the jobsite is more than a quarter mile west of any possible SFO flight path--each contractor is responsible for pulling a crane use permit from the Federal Aviation Administration (FAA). In our case, the top of boom elevation of our mobile crane will be a maximum of 120 feet above mean sea level. After conducting an aeronautical study, the FAA concluded that our equipment poses no "physical or electromagnetic effect to SFO aeronautical operations and procedures". Our crane does not even require any special marking or lighting. Why is this significant? The FAA permit is a zero-dollar cost line item. But since the crane cannot be used until the permit has been pulled, the cost to the project in terms of time is the 3 to 4-week review turnaround time; a potential schedule delay (and potential fine) if this task is not handled in a timely manner. If the bid instructions had not warned of this requirement, our estimating and safety bid teams would have totally missed it. In other words, no one among us could say that our bid teams weren't adequately warned of known potential risks before pricing and scheduling the work). During the mandatory preconstruction conference held in the jobsite trailer, we were encouraged to meet with a design team that obviously were coordinated, had a firm grip on the project, and were motivated to collaborate with the contractors and suppliers.  All stakeholders present agreed the level of detail provided for bidders presented in the geotechnical report and bid instructions was commendable, since it exceeds the "standard of care" usually found in such reports here in our local construction market. Unfortunately, not all of the project stakeholders seem to have gotten the memo. Yesterday morning, we placed approximately 75 linear feet (LF) of foundation grade beams that support walls along the perimeter of the structure; walls that are on the project schedule critical path. This first lift of perimeter walls features tightly spaced reinforcing steel vertical bars (dowels), formed shear keys, and PVC waterstop along the bottom of the wall.  Typically, such an interface at a construction joint among reinforcing steel dowels, keyways, and continuous waterstop presents conditions that require close attention to detail by our place and finish crew. There is little room for error, and plenty of opportunities for sloppy work to cause things to go sideways. We placed the last "clean-up" load of concrete at 10:00 AM.  At 3:00 PM, our labor crew began stripping the keyway boards, water-blasting the concrete spatter from the tightly spaced vertical dowels, and roughening the construction joint to the industry standard 1/4-inch amplitude specified in our construction documents. Our objective was to stay well ahead of the reinforcing steel crew-- standing ready in the staging area-- ready to start hoisting and setting the pre-tied reinforcing steel curtain panels.  Once those steel panels are set, making any repairs or adjustments along the construction joint becomes difficult, expensive, and not schedule friendly. So we were surprised to hear from the project inspector and the General Contractor (GC) that we are not allowed to water blast construction joints on the same day as concrete placement--essentially causing the GC to direct us to stop that activity.  When challenged by our field superintendent, neither the inspector-- nor the GC-- were able to cite the chapter and verse we allegedly violated from the construction, ACI, or industry reference documents. When we met with the GC and the inspector just before quitting time on pour day, no one was able to find any condition that featured loosened aggregate or dislodged waterstop along the freshly prepared construction joint.  Neither the GC nor the inspector were convinced, but an agreement was made to follow up the next day. Over the years, we have learned the hard way that it is best to avoid starting a range war with a difficult inspector, especially this early in the project. On the other hand, we don't want to have any part of setting a precedent that could haunt us for the remainder of the project. We are calling the Hotline to ask if ASCC has a Position Statement or knows of any information published by ACI or other industry source that discusses the minimum age of concrete before joint preparation can proceed; or that tells of a minimum time limit between placement of concrete in adjacent, abutting concrete pours.  Please advise. Answer:  Great question. It seems like whenever we have a natural product with a relatively short shelf life such as concrete, timing is everything. In the concrete industry, for example, we have batch-to-placement time (BTP), which can put a maximum time limit on fresh concrete delivery.  We have minimum wait times before steel can be erected--before certain forms and shoring can be stripped--and minimum recommended wait times before deicing salts and other chemicals can be applied to newly placed concrete flatwork.  Here at the ASCC Technical Division desk, we haven't seen much in existing industry literature per se that specifies or recommends a minimum time--expressed in days, hours, and/or minutes--that must elapse before construction joints can be roughened and prepared for the next, follow-on concrete placement. (More on this below). As luck would have it, a similar question regarding maximum allowable time between placement of two elevated and abutting concrete slabs was fielded in the ACI "Concrete Q&A" column that appears in Concrete International magazine each month ("Allowable Time between Concrete Placements", ACI Concrete International, September 2012). In the response, ACI noted that exact timing is actually considered less important than the general age and condition of--and surface preparation of--the hardened concrete in the "first pour" before the concrete from the "second pour" is placed and vibrated.  The following excerpt, based on ACI 224.3R Joints in Concrete Construction, appeared as follows: "If only a few hours elapse between successive placements, a visual check is needed to be sure that loose particles, dirt, and laitance are removed. The new concrete will be adequately bonded to the hardened green concrete, provided that the new concrete is vibrated thoroughly...Older joints need additional surface preparation. Cleaning by an air-water jet or wire brooming can be done when the concrete is still soft enough that laitance can be removed, but hard enough to prevent aggregate from loosening".  According to the project superintendent, the intensity of the water blast was kept low; out of concern by your labor foreman that a strong blast might dislodge the embedded PVC waterstop--which confirms your crew met the spirit of ACI 224.3R. Unfortunately, a visual review of the construction joint "as built" made late in the afternoon on pour day was not enough to convince the GC and inspector that the work did not violate any of the construction document--or reference document--Quality requirements. You should now be able to use the information presented above to gently educate the inspector--and the GC--that the work in place was prepared correctly, and the follow-on work can proceed. Note: During our literature review to support this Hotline call, we did manage to turn up a reference in the ACI Collection that will be of interest to ASCC members who work on treatment plants, water tanks, and similar concrete structures. In ACI 350.4R-04 Design Considerations for Environmental Engineering Concrete Structures, section 5.2 offers the following design guidance: "At vertical construction joints, 48 h should be allowed between placement of adjacent wall sections". Sayde Hindelang Fri, 14 Mar 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:524 https://ascconline.org/Home/News/articleType/ArticleView/articleId/525/How-to-Assess-the-Health-of-Your-Safety-Management-System-and-what-you-can-do-to-improve-it#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=525 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=525&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/525/How-to-Assess-the-Health-of-Your-Safety-Management-System-and-what-you-can-do-to-improve-it Zach Knoop, General Manager, Caterpillar Safety Services Kris Nagy, Senior Account Manager, Caterpillar Safety Services As Caterpillar enters our 100th year in business, we are constantly evolving with technology, equipment and people. Caterpillar Safety Services is no exception. Zach Knoop, one of the leaders within Caterpillar Safety Services, offers tips on how to assess the health of your safety management system to make sure your company is evolving too. - Kris Nagy We live in a world of systems. The system we should be most familiar with is our body, which requires multiple systems and groups of organs working together to support life. When it comes to protecting the lives of employees from the daily hazards they face, a system with interconnected elements working in concert with one another is required. This collection of interconnected elements is what forms an organization’s safety management system – the foundation for preventing injury and illness, and a component of a resilient safety culture. Each organization’s safety management system varies based on the type of work being performed and the associated risks, but the framework of most contains: A policy statement identifying the organization’s overall commitment to injury prevention. Objectives of the safety management system, along with identifying how those objectives will be met through defined responsibilities and accountabilities at each level of the organization. Documentation of the various procedures, programs, and safety activities used to effectively identify hazards and then mitigate and manage those risks. Ongoing monitoring and measuring the effectiveness of the system, often referred to as safety assurance. Training and communication to execute the elements of the safety management system and capture feedback. When your safety system isn’t producing the results you desire, it’s incumbent upon leaders to assess its health. Ask yourself these questions to help you gain insights into the health of your current safety management system.  Focus - What and Whom is the Safety System Focused On? Does your system focus on achieving perfection? Is the overriding metric of success of the system determined by your recordable injury frequency rate? If you answered yes to either, you may be experiencing (perhaps unknowingly) underreporting of injuries due to the intense focus leaders have on achieving a lower injury rate. This mindset trickles all the way down to frontline employees and can lead to fear of reporting injuries, near misses, and tasks where high risk exposures exist. Tip The safety system should enable employees and leaders on the front lines to analyze, identify, report and address hazards on the job, with increased focus on potential high-risk activities that could lead to serious injuries and fatalities. Identifying hazards and ensuring appropriate safeguards or controls are in place when – not if – someone makes a mistake should be the primary objective of the system. Effectiveness – How effective is the safety system? How well are your policies, procedures, safeguards, training, technologies, and reporting processes understood and followed by workers and leaders? Accountability for working safely requires each level of the organization to know what the expectations are, be equipped to meet the expectations, be measured on their performance, and receive feedback in the form of positive recognition or coaching. If the elements of your safety management system aren’t consistently applied across your organization, you can expect inconsistent results. Consistent application is a leadership function. Does your system support a learning and improving culture? The procedures that govern safe work should not be viewed as static, but dynamic. “Work as planned,” through documentation of safe work practices, may differ from “work as done.”  Tips Getting out and learning what constraints, challenges, and error traps your employees face to accomplish their work is critical to the continuous improvement of the safety system. Learn from those closest to the hazards and improve the system.  Evaluate your system against industry and international safety management standards. Doing this can identify weaknesses within your processes and increase organizational resilience.  Support — How is the safety system supported? Do your leaders champion and drive adherence to the safety management system through their words and actions? You can’t talk your way into establishing and sustaining a culture of safety without “walking the talk.” That means providing the staffing, budget, equipment, engineering controls, and training necessary in ensuring a safe place to work, while personally demonstrating the safe behaviors you want to sustain. Does safety have a seat at the leadership table? At the leadership level, the more filtered the realities of what is happening (good or bad) where the work is being done, the less likely leaders are to respond in a way that connects to and makes a difference to employees.   Tip As the leader goes, so goes the rest of the organization. When leaders, at all levels, demonstrate that safety is a value through their frequent and positive participation in safety activities, employees will feel that they are supported in the pursuit of safe production.   Perception — How does the workforce perceive the safety system? How do employees perceive the system? Is it possible that leadership’s perception might differ from theirs? How safety is managed can be perceived in any of the following ways with the associated outcomes: Command and Control = Fear and Underreporting Complaint and Confusion = Apathy and Disengagement Care and Coaching = Trust and Engagement Which of these three characterize how employees perceive your system? What data do you have to understand how your system is perceived? Tip There are many ways you can learn about your workforce perceptions, ranging from simple tools like using “learning questions” to capture qualitative data during informal conversations, to more rigorous instruments that provide quantitative data, such as a safety perception survey. Whatever you use to gauge perception, the most important consideration is that it provides meaningful and actionable data that you are prepared to act on through strategic improvements.   Your safety management system provides order and structure, while providing confidence that hazards are being identified and the associated risks are being mitigated and managed. Without a system, you’re relying on hope and luck. But just because you have a system in place doesn’t mean you can sit back and expect people to operate perfectly within it. The system needs to be constantly assessed for effectiveness. The most effective systems are part of a culture with a shared mindset that meets challenges with care and curiosity, in which leaders that demonstrate consistent behaviors that positively influence others to work safe, and where a fully engaged workforce is focused on continuous improvement to build ownership of the system.   Just as you sometimes need a professional to help with your personal health, you might also benefit from a professional’s help assessing the health of your organization’s safety system. Caterpillar Safey Services has supported customers for decades in transforming their safety cultures and making them more resilient. To learn more about how our experts can support assessing the health of your system and building a strategy toward a more resilient safety culture, contact us and visit cat.com/safety for more information. Sayde Hindelang Fri, 14 Mar 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:525 https://ascconline.org/Home/News/articleType/ArticleView/articleId/526/PRO-Focuses-on-Concrete-Construction-Productivity#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=526 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=526&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/526/PRO-Focuses-on-Concrete-Construction-Productivity Phil Diekemper, Executive Director - PRO: An ACI Center of Excellence for Advancing Productivity Late in 2024 the McKinsey & Company released another sobering construction productivity article, “Delivering on construction productivity is no longer optional”, explaining why the construction industry must climb out of its productivity rut, but has yet to do so. McKinsey forecasts the need for construction to grow in the next decade or two, however, construction output will be limited by tight labor markets including engineers, craft workers, and project managers. They foresee the near-term labor market as unable to keep up with construction demand. While this dilemma will vary from location-to-location, restriction of immigration will further stress available labor here in the United States. McKinsey believes the only solution to meet construction demand is to improve construction productivity. They conclude that despite individual companies’ efforts to improve productivity, it has flatlined. See the following Figure. The US construction productivity line in aqua green (lowest) illustrates a productivity decline since 2000. When concrete designers consider constructability, labor demands are reduced. Time of construction accelerates, conflict and frustration diminished. Bottom line, owners receive greater value from the concrete contractor. Improving concrete construction productivity is PRO’s focus and mission. PRO’s Constructability Blueprint is a valuable resource that can be used as a guide for all individuals and companies looking to improve their project’s productivity. The digital guide will continually evolve and expand its constructability concepts with input from members and other proven experts in concrete industry productivity. Section 2, “Constructable Design Principles”, is now available! Every owner and designer of concrete can access PRO’s Constructability Blueprint, available for free download. The American Concrete Institute provides a Concrete Constructability Certificate Program. ACI Certificate Programs, delivered through ACI University, encourage concrete professionals to gain in-depth knowledge about particular topics in concrete materials, design, or construction by following a defined online course of study. Once a certificate program has been completed, the participant will receive a certificate and digital badge from ACI that can be shared on social networks, job search sites, portfolio pages, email signature lines, and more. Over 600 users have already earned their Concrete Constructability badge. To be notified of new Constructability Blueprint content, receive PRO news, and learn more about how to join PRO’s mission in advancing productivity, click Subscribe. Sayde Hindelang Fri, 14 Mar 2025 12:30:00 GMT f1397696-738c-4295-afcd-943feb885714:526 https://ascconline.org/Home/News/articleType/ArticleView/articleId/501/February-2025-Guidance-for-Concrete-Contractors36-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=501 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=501&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/501/February-2025-Guidance-for-Concrete-Contractors36-in-a-Series Jim Klinger, Concrete Construction Specialist The Voice Newsletter February 2025  Full Disclosure: Anyone who has cast ice cubes in their kitchen freezer can confirm there is an unseen side effect that occurs during the transformation of liquid water into solid ice--namely a substantial increase in volume.  Material science textbooks say that--under certain boundary conditions-- a volume increase of about 9 percent can be expected once the phase change process is complete. Kitchen ice cube molds typically allow ice crystals to form and expansion to occur free of restraint or confinement.  But what would happen if the molds restrained the material from expanding?  What sort of internal forces would develop? And even more to the point, how could restrained freezing of water affect concrete performance and durability? To get a feel for the kind of forces that can develop when restrained or confined water freezes, physics and chemistry professors like to perform a popular "shock and awe" demonstration in university lecture halls packed with an unsuspecting audience of first-year engineering students. This writer was one of several hundred students enrolled in an introductory chemistry course called CHEM103 during the 1983 spring semester at the University of Maryland. Despite the passage of more than 40 years, the demonstration was indeed one of shock and awe--a sensory event easily retrieved from this old man's memory bank. Unfortunately, video documentation of the 1983 Maryland demonstration is unavailable. But perhaps the next best alternate is a video posted recently by the British Royal Society of Chemistry (RSC). Although the smaller scale of the RSC "ice bomb" demonstration results in a less violent (and quieter) aftermath, there is no mistaking the lesson learned.  When it comes to resisting forces developed when confined water freezes, materials notoriously weak in tension--such as concrete--don't stand a chance. The RSC video is available at the link below. As described above, there was a notable difference between the Maryland and RSC demonstrations related to scale. The Maryland cast iron sphere was larger than a softball. The temperature was lowered by way of a plastic 5-gallon bucket; half full of liquid nitrogen and loosely capped with an 18-inch square makeshift plywood lid. When the cast iron sphere ruptured, the bucket was shattered, the plywood lid was sent sailing, and the explosion was not only heard, but felt. https://www.youtube.com/watch?v=YpQwQx2lMGk So what can we take away from this?  No matter how you personally feel about it, the construction industry has a love-hate relationship with the curious chemical compound called water.  Some trades are devoted to keeping water out at all costs--others want to keep water in.  All it takes is the smallest of leaks to totally wreck a project. Things get a little convoluted when it comes to the concrete business.  On the one hand, we need water to initiate the essential chemical reaction called hydration that occurs when water is mixed with cement. After that, we might even want to use a little water here and there for curing purposes. On the other hand, however, many project stakeholders seem to be spending piles of time and money in a concerted effort to divert water off of--and away from--our work product.    What follows below is just a watered-down sip of how water in two of its forms can affect a concrete contractor. But if you think about it for a while, you will see straightaway that this ASCC Hotline call is just the tip of the iceberg. ___________________________________________________________________ Question: We are in the preconstruction phase of a privately financed concrete construction project located south of the 30-degree latitude line. Work items in our contract scope include reinforced concrete foundations and tilt-up wall panels. There is also a significant quantity of exterior paving slabs intended for employee and customer parking. The project Owner is a well-known manufacturing company based in the Chicago, Illinois metropolitan area. At any one time, their active jobsites can be seen in almost every geographic region across the USA.  Despite having a national presence, we understand their project designs are typically performed by architects and engineers based in Chicago--above the 40-degree latitude line.  And therein lies the issue driving our call to the ASCC Hotline for guidance.  Here's why. The structural drawing general notes feature a blanket requirement calling for the use of air entraining admixtures in all project concrete; including the foundations, tilt-up panels, and parking slabs in our scope. During the pre-bid period, our estimators were aware of this requirement. Since this is a private project, we made a business decision to not submit any pre-bid RFI's regarding the use of air entraining admixtures.  Further, we did not qualify our bid proposal calling attention to air entrainment. We have been placing structural concrete in our regional market since 1959, and in all those years neither we--nor our concrete supplier--have ever been required to provide air entrained concrete. During the post-award buyout of the ready-mix concrete, none of the three price quotes we solicited from the local ready-mix suppliers included any cost of air entraining admixtures. Shortly after we selected our successful concrete supplier, mix designs were proportioned without air entrainment and submitted to the design team for review. Last week, we learned the design team has rejected our mix design submittal. Our customer--themselves a national general contractor (GC) with extensive experience in our regional market--agrees with our position and arranged a virtual meeting with the licensed design professional (LDP) to discuss the rejected submittal. That meeting took place this morning.  The LDP explained that their hands are tied; that their construction documents were prepared in accordance with the ACI Code durability requirements outlined in Table 19.3.1.1. (The version of the ACI 318 Code used for design purposes and referenced on the structural drawings is ACI 318-19 Building Code Requirements for Structural Concrete, hereinafter referred to as "ACI 318"). We (including the GC and the ready-mix supplier) explained our position that--based on our collective experience in our regional market--the geographic location of the jobsite poses almost no risk of freeze-thaw deterioration. The LDP asked us to provide substantiation, and we arranged to meet again ASAP. Looking back on it, we acknowledge that we should have raised the issue of air entrainment during the pre-bid period. Nevertheless, we are convinced that the structural design prepared above the 40-degree latitude line includes assumptions of exposure conditions that do not apply to our project.  We are looking to ASCC for advice on how best to substantiate our position and help convince the LDP that air entrainment should not be required. Answer:  The LDP is correct in saying that their design is based on the durability requirements stated in ACI 318. They are well within their right to take that position, no matter how conservative their Code interpretation may seem to you. So the question then becomes "How tight are the LDP's hands really tied?"  As all ASCC Hotline callers know, the Quality of hardened concrete is judged by three characteristics, namely compressive strength, durability, and dimensional stability. In other words, the hardened concrete must be strong enough to carry design loads, durable enough to withstand various types of deterioration, and must remain in the right place after hardening.  ACI 318 defines "durability" as "the ability of a structure or member to resist deterioration that impairs performance or limits service life of the structure in the relevant environment considered in the design".  ACI 318 section 19.3.1 describes four basic durability exposure categories:  deterioration caused by freeze-thaw (Category Type F), deterioration cause by sulfate attack (Type S), deterioration caused by water (Type W), and deterioration caused by corrosion (Type C). At issue in your case is exposure category type F, freeze-thaw. According to ACI 318 commentary section R19.3.1, the risk of concrete damage is a function of water saturation when the concrete temperature cycles from freeze to thaw, described in an example as follows: "If the top 3/8 in. of a slab or outer 1/4 in. of a wall is saturated, those portions are vulnerable to damage from freezing and thawing, regardless of how dry the interior may be". According to ACI 318, the rationale supporting the requirement for air entrainment is "for any portion of a member to be resistant to freezing and thawing, that portion of the concrete needs to have sufficient entrained air and adequate strength". It is crucial to note here that ACI 318 is replete with "check and balance" provisions intended to assist in rinsing out "grey area" issues such as yours. Resolution can be accomplished by applying healthy doses of engineering judgment. The concept really isn't all that complicated, but it is certainly often overlooked. For example, ACI 318 commentary section R1.3.2 advises the LDP audience as follows: "The minimum requirements in this Code do not replace sound professional judgment or the licensed design professional's knowledge of the specific factors surrounding a project, its design, the project site, and other specific or unusual circumstances to the project". Additional support for your position can be found in ACI 318 commentary section R19.3.1 as follows: "The likelihood that concrete in a member will be saturated depends on project location, member location and orientation in the structure, and climate.  Records of performance of similar members in existing structures in the same general location can also provide guidance in assigning exposure classes". On your project, there are three classes of structural concrete that require exemption from the air entrainment requirement: foundations, tilt-up wall panels, and exterior parking slabs.  Based on the above, we recommend the following items be included in your request for relief from the LDP. The first item that can easily be compiled by your project engineer is a weather history recorded as close as possible to the project jobsite.  This information should be considered by the LDP consistent with the two ACI 318 excerpts cited above.  Put another way: prove to the LDP that a waiver of the air entrainment requirement is a very low-risk proposition. This argument can be most effective for exemption with the foundation and parking slab mixes. The next item that should be included in your submittal is a project concrete placement schedule.  When will the foundation concrete and parking slab concrete actually be placed? Finally, for the tilt-up wall panels, the most significant document that can be brought to bear is the position statement prepared by the Tilt-up Concrete Association (TCA) that addresses the use of air entraining admixtures in concrete proportioned for use in tilt-up wall panels.  A link to the TCA air entrainment position statement is given below: https://tilt-up.org/tilt-uptoday/2023/09/22/collective-position-on-specification-of-air-entrainment-in-concrete-for-tilt-up-panel-construction/ The TCA position statement is summarized as follows: "Tilt-up concrete panels are vertically oriented slabs of concrete with limited exposure to conditions of saturation.  Furthermore, since these wall panels are primarily vertical and located above grade conditions, they have virtually zero exposure to conditions of deicing salts.  Therefore, the Tilt-up Concrete Association believes that the use of air-entraining admixtures is not required to protect the surface of the panels from delamination due to freezing and thawing cycles during saturated conditions". The TCA position statement does not mean, of course, that the LDP does not need to investigate the weather conditions likely to be experienced by the concrete members built in your regional market. But based on the above, we believe you stand a good chance of getting relief from the LDP. Let us know how it turns out. Note: You took a risk at bid time by not carrying the cost of air-entraining admixtures in your price.  In the unlikely event the LDP enforces the requirement, you will have to absorb that cost.  At the same time, it may be beneficial to view this through a lens focused on the Owner's side.  No matter how it goes, the Owner never pays the cost of the admixtures, and stands to save on testing and inspection costs if the waiver is granted as well. Sayde Hindelang Tue, 18 Feb 2025 07:30:00 GMT f1397696-738c-4295-afcd-943feb885714:501 https://ascconline.org/Home/News/articleType/ArticleView/articleId/502/Non-Pour-Day-Visit-a-major-material-or-equipment-supplier#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=502 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=502&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/502/Non-Pour-Day-Visit-a-major-material-or-equipment-supplier Michael Hernandez, Technical Director The Voice Newsletter February 2025  Its February, a polar vortex is dropping in and the local (Denver) forecast high temperature for 2 days from today is 14F. No placing exterior concrete in that. Most batch plants here shut down at 20F. Back in my operations days a few yards ago that sounds like a great day for either catching up on office paperwork, staff training or a field trip with a Superintendent and an office person. This winter I would encourage each team to schedule some field trips to visit a major material or equipment supplier, you will learn a lot about a supplier’s operation when you visit, and they are likely happy to show you, their facility. Meet some detailers, a batch man and other “behind the scenes” people that are critical to your success in 2025. See some formwork and equipment options. Bring some company SWAG like hard hat stickers or T-shirts. Those friendly gestures go a long way when you need a favor in the heat of the summer, crews are scattered, and placements are going 2-3/day. Some ideas: Rebar Fabricator This is one of my preferred field trips. The benders and shears might be silent on a bitter cold day, but if they are indoors, many are, it is a sight. Can see the logistics of how rail cars (ideally) or trailer loads of stock rebar come in, how overhead gantries bring bundles to a table and shake out the quantities needed. Then bars slide to shears and bend tables. Watching the auto bender take a spool of #4 bars and turn them into column horizontals or beam stirrups is mesmerizing. Do they run 1 shift? 2 shifts? Seasonal 2nd shift? Can understand their degree of automation, capacity, organization, cleanliness, quality control, safety culture and tagging system. All of those factors lead to complete orders and are necessary to know for large projects. Nothing worse than haggling right before the rebar inspection over whether a truckload that was supposed to have certain bars of a specific quantity had them or not then hot shotting the shortage. Visit a few fabricators and you will be able to internalize whose shop is most likely to get a big project done quickly and accurately. May also see some rebar accessory options you had not thought about, like different chairs or couplers or terminators. There are many styles, all come with pros and cons as well as premium applications like architectural concrete. Site logistics a challenge? Had projects where after a shop visit, we discussed with trucking operations how many trailers (1, 3...5?) they could leave on our jobsite and how they rig them so a crawler could plop one empty trailer on another to bring back to the fab shop after unloading them at our leisure. Helpful when the spring mud was deep to keep the rebar clean. The shop’s upside is the truck, and drivers are not sitting on standby waiting for a forklift or crane to unload them. Just detach the full load, hook up to an empty or stacked double empty and off they went. PT Fab Shop Post tension cable suppliers can be regional, hopefully there is a local one near you. Can see how the raw cable has their signature color of plastic applied to encapsulate the cable, cooled and spooled. Then the cables are cut to length, heads are pressed on, accessories applied and how the bundles are coded. Again, the size of the operation, from a handful of guys in a few hundred square feet to tens of thousands of sf to service a region.  Talk with the detailers about pocket former options, ram calibration frequency and ideas about making your next project more constructable. Resolve issues like who is quantifying the carrier bar, detailing the busting bars (them or the EOR), are they seeing issues of how the bundles will be grouped or how the heads will fit at the face of a beam and column interface. Formwork Yard Winter is the time to see new alternatives in panels and shoring at a local formwork shop, particularly if you missed World of Concrete. Of course, WOC had everything. What you really need to know is what is locally available and what will need to be shipped in from elsewhere as soon as things get busy. Posts with tripods or shoring frames? Wall formwork pour rates? Can the guys lift the wall panels by hand or is equipment moving it all the time? Plywood options from MDO to HDO, plastic faced and their tradeoffs. Doka, Meva and Titan Formwork are Sustaining Members of ASCC. They all have a number of yards around the country, check them out. Concrete Batch Plant Ok, possibly not the most fascinating one on the list, but you need to know. How modern does the plant look? Central batched or dry batched? How many cementitious silos? Ideally 2+. How many aggregate bins can be loaded simultaneously, ideally 3-4, one is for sand. They often have a primary aggregate, like #57, that they use in most mixes, but some states will have unique blends. Inquire if the sand is natural or manufactured, you probably know this already, they will often have some optional aggregates or sands for a small premium. Manufactured sand often has a higher water demand. Ask about moisture monitoring of the sand stockpiles and how often this is checked. Understand whose cement and SCM’s they silo.  They may have several cement suppliers to diversify their risk, or certain suppliers go to specific plants in the area. Ask if the trucks run in reverse after wash down to get all the water out of the drum or if they use a “rule of thumb” to estimate how much water is in the drum. Confirm the hold water will be printed on each ticket and watch the batching process a few times. The batch man does not often see outsiders so hopefully they are thrilled to show an interested person how a truck is loaded. See the integral color and admixture bulk storage equipment. There is more happening than you might expect. Then go to the backup plant nearby. Do they silo the same cement and SCM options? Better to know now than mid-slab placement that one silos I/II, another IL or IP cement. Cement Manufacturing Plant These are quite interesting beasts. At least I think so. At one end of the operation, blasting in a limestone quarry, at the other end trucks and rail cars being loaded with finished cement. Lots of crushing, milling, pre-heating, melting and grinding in between. I was most surprised by the number of quality control checks happening in each step of the process. It’s possible that the closest kiln may be in winter maintenance shutdown mode, if so, it will be easier to talk. If operating, they go 24/7 so be prepared for very large equipment, heat and some noise. The kiln monitoring room is watching a giant flame turn rocks into molten klinker and continuously monitoring numerous inputs and parameters, fun stuff. The finish mill is where the clinker, gypsum, limestone and possibly an SCM are ground and blended to make the final product, cement. Inquire if they focus on 1 main cement or have a diverse set of cements they make for masonry, oil wells (think high heat and pressure) or blends required by a DOT. They probably make more cement options than you had thought about. I might make a cement plant overview tour its own Voice article someday for a deeper dive on the steps in the cement making process and equipment like XRF, XRD and particle size analyzers to variety quality. Sustaining Member Cemex might be able to provide both a batch plant and a cement plant tour in the right city. Caterpillar or Crane Yard ASCC Sustaining Member Caterpillar has been an excellent host for the last few years so its easy to think about visiting them. Equipment advancements have been made the last few years that improve safety and productivity. Many dealers have a dirt stockpile out back that they let customers get a few minutes in the seat to feel how smooth the new model will operate. There will be more models and attachments than you can think of. Ask about the ASCC Member discount, which can be over $1000 on the right equipment. Crane yard, similar principles. Maybe there is a 50 ton RT machine that is a nice fit between a 12k forklift and a medium crawler. Maybe an all-terrain truck crane that can roll in, pop up on outriggers and load a few truckloads to some back of project location, saving the crew from carrying it across a slab. Then there are the really big crawlers, my favorite. Be aware of ground bearing pressure and capacity, they are darn heavy. I have been partial to Manitowoc’s most of my career. 888 awesome. 2250 on a barge? Let’s go! The Manitowoc 16000 (440-ton capacity) is the only rig with the muscle within 500 miles to get that 55’ sandwich panel off the floor? It’s on!! When you just have to lift that 220,000 lb beam or panel, you have got to have fat stacks of steel on the counterweight tray. Options, we all like options. Manitowoc 16000 lifting tilt panels while on timber crane mats Pump or Laser Screed Yard Schwing and Putzmeister are both Sustaining Members of ASCC. ASCC members both buy from them directly or rent from a local pumper that buys from them. Big booms have big outrigger spreads. Use the opportunity to discuss pumping strategies. I do love a placing boom, probably the best option for placing slabs when higher than 5 floors. Dedicated stationary placing booms, SPB’s, rent by the month, detachable from a truck, by the hour. High-capacity trailer pumps are also a must in the mid-rise and high-rise market. This is nothing new if you are already doing this scope, but they keep evolving. 20+ years ago a 52-meter pump was BIG! Now a 65 meter on 7 or 8 axels can roll on site.  This one might involve a trip to their U.S. corporate headquarters in Sturtevant, WI or St. Paul, MN. https://www.putzmeisteramericapresents.com/ or https://schwing.com/home.html These machines are a major investment so plan, plan and double check the plan. Schwing Separate Placing Boom 35m on pedestal mast Putzmeister 63m Boom Pump with steerable rear axels Somero is another ASCC Sustaining Member. The Sky Screed was my best discovery at 2025 WOC, even though it has been out for a few years. Can stand on a post tension deck and screed the slab with a smaller crew vs hand screeding and obtain higher F numbers. If the project tower crane has the capacity for a placing boom it can fly the Sky Screed too. Link: https://www.somero.com/products/stationary-screeds/sky-screed-36/ Somero Sky Screed with 36’ boom In summary, don’t waste a winter non-pour day. Visit a shop, plant or yard. You will improve understanding and relationships. We all need an ally at times. Best to know who has the ability to come though when the need arises and what options they have in their toolbox. Sayde Hindelang Tue, 18 Feb 2025 07:30:00 GMT f1397696-738c-4295-afcd-943feb885714:502 https://ascconline.org/Home/News/articleType/ArticleView/articleId/499/January-2025-Updates#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=499 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=499&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/499/January-2025-Updates ASCC Shines at World of Concrete 2025: A Celebration of Community, Camaraderie and Recognition The American Society of Concrete Contractors (ASCC) made a powerful impact at the 2025 World of Concrete (WOC) in Las Vegas, showcasing its commitment to technology, safety, and industry leadership. From the sold-out Kickoff Bash to the hands-on Decorative Concrete Council (DCC) and Concrete Polishing Council (CPC) Experience Booth, and the innovative ASCC Central Hall Booth, this year’s presence was one of ASCC’s most successful yet! A Night to Remember: The ASCC World of Concrete Kickoff Bash The ASCC set the tone for the busy week with its annual Kickoff Bash, one of the most anticipated networking events at the World of Concrete. ASCC members and concrete professionals from across the country gathered at Caesars Palace for an evening that featured the College Football Playoff Championship Game pitting Notre Dame against Ohio State, who ultimately won the game and claimed the National Championship. Not to be overshadowed by the game, the evening also boasted new food, drink selections, great camaraderie, and networking, strengthening the bonds that make ASCC a leader in the concrete community. With a record-breaking turnout, the event provided a unique opportunity for contractors, suppliers, and industry experts to connect, exchange ideas, and build relationships that move the industry forward. Honoring Excellence: 2025 ASCC Decorative Concrete Hall of Fame Inductions During the week’s festivities, ASCC proudly welcomed three new members into its Decorative Concrete Hall of Fame, recognizing their dedication, expertise, and contributions to advancing the decorative concrete industry. Chris Klemaske, Sundek National Accounts (#1), Bent Mikkelsen, Concrete Décor Magazine (#2(, and Lee Ann Harris, Decorative Concrete Institute, Inc. (#3) were inducted into the American Society of Concrete Contractors Decorative Concrete Hall of Fame on January 22, 2025, at the DCC/CPC Experience Booth at the World of Concrete held in Las Vegas, NV. Their leadership, mentorship, and technical innovations have shaped the decorative concrete industry’s best practices and inspired the next generation of contractors. The Hall of Fame induction ceremony was a highlight of the DCC/CPC Experience Booth, where attendees gathered to celebrate the careers of these industry giants as well as past inductees. The new event was packed from start to finish. The DCC/CPC Experience Booth Shines In addition, the Decorative Concrete Council (DCC) and Concrete Polishing Council (CPC) Experience Booth provided an interactive, hands-on experience for attendees eager to explore the latest techniques, tools, and trends in decorative and polished concrete. Experts from ASCC led live demonstrations, sharing best practices in stamping, staining, polishing, and overlay applications. Attendees had the chance to see decorative and concrete polishing exhibits, gain insights from industry experts, and take-home practical knowledge to enhance their own projects. The booth’s interactive format and Ted-Type Talks made it one of the most visited areas of the World of Concrete, further solidifying ASCC’s reputation as a leader in decorative concrete. Innovation and Safety at the ASCC Central Hall Booth This year, the ASCC Central Hall Booth was a must-visit destination, featuring two groundbreaking initiatives: The ASCC AI Bot – A cutting-edge artificial intelligence tool designed to assist contractors with technical questions, best practices, and troubleshooting in real-time. This innovative resource provided by ASCC Associate Member From the Future demonstrated how AI can enhance efficiency and decision-making in concrete construction. It is hoped to implement the ASCC AI bot late in 2025. Narcan Training & Free Narcan Kits – Recognizing the importance of workplace safety beyond traditional construction hazards, ASCC offered lifesaving Narcan training. Attendees who completed the brief yet comprehensive training session received a free Narcan kit, equipping them with the knowledge and tools to potentially save lives in overdose emergencies. The combination of technology, education, and safety initiatives at the Central Hall Booth showcased ASCC’s forward-thinking approach to supporting and protecting the ASCC community and beyond. The 2025 ASCC World of Concrete programs and events showcased the culture, technology, programs, services, and unwavering commitment that define the ASCC. From the Kickoff Bash that fostered industry connections to the DCC/CPC Experience Booth, where hands-on learning brought decorative and polished concrete to life, ASCC demonstrated its dedication to education and craftsmanship. The Hall of Fame inductions honored the legacy of industry pioneers, while the Central Hall Booth introduced cutting-edge advancements like the ASCC AI Bot and emphasized safety with lifesaving Narcan training. Each initiative reflected ASCC’s mission to empower contractors, advance the industry, and uphold the highest standards of excellence. As ASCC continues to lead the way, its presence at WOC 2025 reaffirmed its role as a pillar of innovation, leadership, and support for the concrete construction community. Sayde Hindelang Thu, 30 Jan 2025 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:499 https://ascconline.org/Home/News/articleType/ArticleView/articleId/500/A-Message-from-the-Board-of-Directors#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=500 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=500&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/500/A-Message-from-the-Board-of-Directors ASCC Elects New Officers and Directors for 2025 At the ASCC Annual Meeting held on Monday, January 20th, 2025, at 4:30 P.M. PST at Caesars Palace in Las Vegas, NV, the ASCC announced its newly elected Officers and Directors for 2025. Cory Lee (Martin Concrete Construction) was announced as the ASCC President replacing Chris Klemaske (Sundek National Accounts). In addition, the following persons were also announced to serve alongside existing Board members in 2025: New Officers/Re-elected Officers President Cory Lee, Martin Concrete Vice Presidents Maizer Ouijdani, Conco Anthony DeCarlo, Jr., Dominion Concrete Services Greg Hryniewicz, Hyde Concrete Ashley Stamper, Danko Concrete Construction Secretary/Treasurer Aaron Gregory New/Re-elected Directors T.R. Kunesh, Somero Enterprises Tim Manherz, Encore Concrete Sean McGillicuddy, McGillicuddy Concrete Marc Ness, DPR Construction Nigel Parkes, Parkes Technologies Keith Wayne, Wayne Brothers Sayde Hindelang Thu, 30 Jan 2025 08:30:00 GMT f1397696-738c-4295-afcd-943feb885714:500 https://ascconline.org/Home/News/articleType/ArticleView/articleId/495/2025-Fall-Protection#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=495 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=495&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/495/2025-Fall-Protection Ensuring safety on concrete construction sites is not just a regulatory requirement—it’s a commitment to preserving lives and livelihoods. Fall protection remains one of the most critical aspects of construction safety, as falls are a leading cause of workplace injuries and fatalities in the industry. The American Society of Concrete Contractors recognizes the importance of proactive measures to prevent falls and is dedicated to providing guidelines, training, and resources to foster a culture of safety. This article explores key strategies, tools, and best practices for effective fall protection, empowering contractors and workers to minimize risks and maximize workplace safety. Federal Fall Protection Guidelines The key components of Federal Fall Protection fall under OSHA 29 CFR Part 1926, Subpart M. General Requirements Fall protection must be provided at elevations of 6ft or more Fall protection is required for workers working above dangerous equipment regardless of height. Fall protection Systems Guardrail system: Barrier systems designed to prevent workers from falling to lower levels. Safety net system: Systems placed below elevated working areas to catch workers in event of falls. Personal Fall Arrest Systems (PFAS): A system consisting of an anchorage, connectors, and a body harness to arrest a fall. Specific Areas and Activities Roof work: Workers on roofs with unprotected sides or edges must use fall protection. Leading Edges: Fall protection is required for workers constructing leading edges at elevations above 6ft. Excavations: if an excavation is 6ft or deeper and not protected by a guardrail Steel Erection: special rules apply but fall protection is required above 15ft Training Requirements Employers must provide fall protection training to workers exposed to fall hazards Training must cover the nature of fall hazards, the correct use of fall protection systems, and the proper way to inspect fall protection equipment. Inspection and Maintenance Employers must ensure that fall protection equipment are inspected regularly for wear damage and other deficiencies. Site specific Plans For some complex job sites, employers are required to develop and implement a site-specific fall protection plan Penalties for Non-Compliance Failure to comply with OSHA’s fall protection guidelines can result in significant fines, citations, or even job site closures. Steps to follow if an elevated fall happens at your job site. Remain calm and assess the situation Initiate emergency response Perform rescue Provide medical assistance Preserve the incident scene, including photo and/or video documentation. Conduct a thorough investigation Notify OSHA (if applicable) Review and update safety procedures Provide support to workers By taking the steps listed above, employers can ensure the safety and well-being of their workforce, minimize the risk of future incidents, and maintain compliance with OSHA standards. Conclusion Fall protection is not just a regulatory requirement—it’s a cornerstone of creating a safe and productive work environment. Every worker has the right to return home safely at the end of the day, and every employer has the responsibility to ensure their safety by implementing and maintaining effective fall protection measures. By prioritizing comprehensive training, regular inspections, and a culture of vigilance, we can significantly reduce the risks associated with falls and set a standard of safety excellence in the construction industry. Investing in fall protection is an investment in the lives, livelihoods, and the future of our workforce. Jared Grossenbaugh GCM Contracting Resource Manager Sayde Hindelang Wed, 29 Jan 2025 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:495 https://ascconline.org/Home/News/articleType/ArticleView/articleId/496/A-Farewell-as-DCC-Director-Reflecting-on-Two-Years-Welcoming-Change-and-the-Power-of-Active-Listening#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=496 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=496&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/496/A-Farewell-as-DCC-Director-Reflecting-on-Two-Years-Welcoming-Change-and-the-Power-of-Active-Listening This is my last article as DCC Director. It has been a whirlwind and quick two years. My congratulations to Micheal Campbell with Trademark Concrete who will take the reins during the World of Concrete. I know he will do an outstanding job. Over the past 23 newsletters I’ve discussed a range of topics. Some specific to decorative concrete, some general business management and sales, and a few along the lines of self-help or self-improvement. This last topic isn’t one that I’ve been saving as a finale, and although it is January, it isn’t because it’s a New Years resolution (though it DOES make a good one, if you’re still searching). It is a life skill that I must continually work on and it’s an important one in both your personal and professional life- listening, active listening. When one describes a good communicator or leader we are usually talking about a great speaker/presenter, not a great listener. But, oh, how important listening is. Business owners and managers that listen well create organizational cultures where people feel heard and valued and that reduces turnover and increases productivity and job satisfaction. Listening is also ranked higher than speaking and presenting as the most important communication skill. In our personal relationships communication is the key to happiness and success. That communication starts with listening. Our spouses, children, and friends deserve our undivided attention and are far more important than any article we may be reading, show we are watching, or social media we are scrolling. There are several techniques you can use to become a better listener. The first is “listen until the end”. Are you really listening or are you already thinking about your response? Or do you interrupt the other person with a solution while they are still speaking or a similar story of your own before they finish (thus making the conversation all about you)? Let the other person finish their thoughts. Then and only then is it your turn to speak. Next is “listen to understand”, not to respond or solve the issue. For instance, some conversations might require you to repeat what you heard…to make sure you’re on the same page. You might ask “so what you’re saying is…” or summarize and ask “did I get that right”? or “what am I missing”? When listening, do so for both content and the relationship. For the content, listening to understand is key. For the relationship dimension listening until the end is key. I found it also helps to look the other person in the eyes. Ever have a conversation with someone who won’t stop scrolling or put their phone down? Or won’t stop what they are doing and look at you? Makes you feel unheard or unimportant. I struggle with conversations like this all the time. I can be watching a game, or just now, typing out an article, when someone talks to me and I give the obligatory “uh huh” or “yes, Dear” and have no idea what I’ve just agreed to. Once you have good foundational listening skills you can begin listening for values, building your intuition and perception skills. Understanding your employee’s values and how they impact their behavior will make you a better leader. Our values influence what we perceive as challenges, how we take criticism, and what motivates us.  When you really listen to someone, over time you learn what’s important to them and react accordingly. Understanding their values gets you beyond the surface issue to what is triggering their emotions. You may not solve every problem on the spot, but acknowledging your employee’s values creates an engaging environment for everyone. I look forward to seeing all of you at the World of Concrete and having those meaningful conversations that make ASCC a great organization. Rich Sayde Hindelang Wed, 29 Jan 2025 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:496 https://ascconline.org/Home/News/articleType/ArticleView/articleId/497/January-2025-Guidance-for-Concrete-Contractors35-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=497 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=497&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/497/January-2025-Guidance-for-Concrete-Contractors35-in-a-Series Question: We are preparing to pump, place, and finish a reinforced concrete slab on metal deck (SOMD) in a 4-story (e.g. 4 elevated decks) structural steel-framed office building. Each floor slab has an area of 100,000 gross square feet (GSF), which we plan to complete in 4 each 25,000 square foot (SF) pours per floor, or 16 total placement days.  We have scheduled our first concrete placement in two weeks. To date, our contract scope (pile caps, grade beams, and anchor rods for the steel columns) has been on time and under budget.  All foundation concrete placed to date has been tailgated, and the slab on grade (SOG) is now scheduled near the end of the project due to pending Owner (future tenant) design changes. Ownership has been issuing our progress payments in a timely manner, and we have a good relationship with the Owner's inspection team. There are only 3 noncompliance reports (NCR) outstanding that belong to us which are very minor in nature and will be quickly resolved after we pour out the SOMD.  The structural engineer has been fair all along, but tends to take a conservative approach to any issues that have arisen. The metal decking sheets furnished and installed by the steel erector feature 3-inch-deep flutes plus an additional 3 1/4 inches of reinforced concrete "topping", resulting in a nominal concrete thickness at each flute of 6 1/4 inches.  The SOMD are designed as normal weight concrete (NWC), reinforced with welded wire mesh reinforcing sheets furnished and installed by others.  During the pre-bid period, the metal deck sheets-originally specified as "vented"-were changed to non-vented at our request. According to the metal deck product data, the neat (aka "exact") volume of concrete required to fill a 3 1/4-inch topping over every 100 SF of floor surface area is 1.466 CY. In other words, a 25,000 SF SOMD placement will require a minimum 367 neat CY concrete purchase. To account for overage, waste, and deck deflection, our estimator carried an additional 1/2 inch of concrete spread over the entire floor area.  This adds another 37 CY of NWC--roughly 10 percent-- resulting in a final estimated concrete purchase quantity of 404 CY per pour. During the SOMD preconstruction conference held at the jobsite yesterday, the concrete pump operator was asked how the pump rubber hose system was going to be primed at the start of each day's placement.  Would he use water to prime the pump, or a cementitious grout slurry mix, or a prepackaged proprietary product?  The pump operator replied that water would be out of the question, and the final decision has not been made regarding the primer material. At that point, the structural engineer stated that a pump primer material and placement plan must be submitted and approved before we can begin placing the SOMD. We would like to use a cement slurry mix prepared by our ready-mix concrete supplier, which our estimator agreed to during the concrete material supply buyout after we were awarded the job. We wish to prime the pump with about 1 cubic yard (CY) of slurry, which--at a 9-inch slump--would be spread out over the pour areas up on each elevated deck and left in place.  In other words, the slurry coating would be incorporated into each slab.  We did not raise the leave-in-place scenario during yesterday's meeting.  Since the engineer is fair--albeit conservative--we wanted to check with the ASCC Hotline first for guidance on how we might successfully package the primer placement submittal and get it approved.  Please advise. Answer: This is a great question, since it features recurring themes fielded here at the ASCC Technical Division.  The last time we addressed such various SOMD issues was in "Guidance #23", which appeared in the November 2023 issue of the ASCC VOICE.  A memory-refreshing link to Guidance #23 is as follows: https://ascconline.org/Home/News/articleType/ArticleView/articleId/377/categoryId/33/Guidance-for-Concrete-Contractors23-in-a-Series January 2025 Pump Primer Update:  Three years ago, I was appointed to the American Concrete Institute Construction Liaison Committee (CLC) to serve a three-year term which ends at the conclusion of the upcoming Spring 2025 ACI Convention which will convene in Toronto, Canada March 30-April 2, 2025. The CLC Committee Mission is stated as follows: "Advise the Board of Direction on the needs of the concrete construction industry as it relates to establishment and operation of committees, programs, and activities to address contractors' needs and problems within the Institute". Part of the ACI CLC duties performed over the past 3-year term included review of many ACI Practices, Codes, and Specifications under consideration for proposed revisions to existing documents or incorporation into the ACI Collection for new documents.  One such review included proposed revisions to ACI SPEC-311.7-18: Specification for Inspection of Concrete Construction.  ASCC proposed a revision to section 3.2.4, which originally called for the inspector to "Verify that grout used to lubricate the pump hose is not incorporated into the placement" as described in Guidance #23. The ASCC proposed revision to section 3.2.4 we submitted to CLC read as follows: "Grout used to prime pump system can be left in place when approved by the Licensed Design Professional (LDP), especially in large placements or slabs on metal deck".  In general, the status of any proposed revisions submitted to CLC by ASCC are kept under wraps until the document is made available to the industry as a "public discussion" version. Last time we checked, the public discussion version of section 3.2.4 reads as follows: "Verify that grout used to lubricate the pump hose is not incorporated into the placement unless approved by the RDPRC (Registered Design Professional in Responsible Charge)".  Let's hope this public discussion revision makes it over the finish line when the final ACI SPEC 311.7 is published by ACI. _________________________________________________________________ Question: More and more we are seeing the prefix "PRC" in titles to certain ACI documents.  For example, we noticed a document reference in a recent Concrete International article titled "Converting Core Strengths to Equivalent Specified Concrete Strengths" that appeared in the November 2024 issue of ACI Concrete International. The document reference was "ACI PRC-214.4-21 Obtaining Cores and Interpreting Core Strength Results--Guide". Can the Hotline tell us what the prefix "PRC" stands for? Answer: The acronym is short for "Practice", and is used in the titles of ACI Guides and Reports.  ACI codes feature the prefix "CODE", and ACI specifications feature the prefix "SPEC".  A comprehensive listing of ACI documents featuring these prefix designations can be found at this link to the ACI Collection of Concrete Codes, Specifications, and Practices-2024: https://www.concrete.org/store/productdetail.aspx?ItemID=COL24PACK&Format=HARD_COPY&Language=English&Units=US_Units ___________________________________________________________________ Sayde Hindelang Wed, 29 Jan 2025 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:497 https://ascconline.org/Home/News/articleType/ArticleView/articleId/498/Midwest-Pavement-Scaling-Study-Request-for-Additional-Participants#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=498 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=498&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/498/Midwest-Pavement-Scaling-Study-Request-for-Additional-Participants Over the last few years there has been an increase in scaling observed in roadway and parking lot pavements in the Midwest. Several calls to the ASCC hotline, member photos, newspaper articles and issues noted by ready mixed producers and associations in multiple states are discussing this outcome. The purpose of this newsletter article is bringing awareness that several teams have started or will start parallel studies attempting to identify which factors are most likely contributing to pavement scaling and to invite participation by more ASCC contractors and ready mixed producer teams. In an attempt to inform which issues are contributing to pavement scaling Hahn Ready Mixed stared a study in August of 2024 using 5 primary variables on (92), 2’x2’ test pads. The cost to set up a parallel study is only a few thousand dollars. The challenge is to have someone that will apply deicing chemicals and/or salts as often as the local roadways receive it during two winter seasons.   The Hahn Ready Mixed test pads will be exposed to freeze thaw conditions in Davenport Iowa with a combination of magnesium chloride prior to snow or freezing conditions, supplemented with rock salt each time the city applies them. After each winter season photos will be taken and reviewed by a panel of judges for deterioration, without revealing which variables are applicable to each photo. The five variables being evaluated in the Hahn Ready Mixed study (link: https://hahnrmg-cdn.terrostar.dev/cms/wp-content/uploads/2024/11/Campaign_35.pdf) are: Slag – The slabs were all placed with either a IL (11) with 21% Class C fly ash replacement or a 65% IL(11), 21% slag, 14% Class C fly ash mix. Surface Vibration – half of the pads will be vibrated with a screed and the other half hand finished. In Davenport there has been a scaling correlation with parking lots placed with truss screeds or laser screeds. Unclear how intense the surface vibration was during the initial placements. Speculation is that either over vibration is affecting the near surface air entrainment or there is poor crew access to apply initial curing or intermediate curing chemicals due to the large area placed in a short period of time. Curing Compound: Some pads were not cured. Others received curing by either a wax based compound, PAMS (Poly-Alpha-Methyl-Styrene) curing compound, sodium silicate based cure or a solvent based cure and seal. Curing Timing – Among the test pads that received curing, half were applied 45 minutes after screeding and half 4 hours after screeding. The evaporation conditions on the day of placement were reported as ~0.15 lbs/sf/hr. Sealers – Sealers are often applied to protect against deicing chemicals and brines. In the study 1/3 had nothing applied, 1/3 received a silane/siloxane sealer 30 days after placement, a 1/3 received an admixture in the concrete which is intended to perform as an integral sealer. All mixes used the same #67 limestone and natural sand. All pads were air entrained and had a polycarboxylate high range water reducer dosed at 2oz/100 lbs cementitious. They were placed over crushed limestone in late August conditions, starting at 85F and peaking at 93F with ~60% humidity and ~10 mph wind. ASCC invited thirteen other state ready mixed association representatives, PCA, NRMCA and a handful of ASCC paving contractors to provide input on the Hahn study and possibly run a parallel study. The Tennessee Concrete Association, TCA, and ASCC contractor Stephens & Smith Construction (Nebraska) are planning to run a parallel study. Several other state ready mixed associations are discussing running studies with their local materials, potentially with other finishing techniques or curing methods. Options already noted that could have been study variables: Evaporation retarders and finishing aids – ASCC member have reported an increase in the need for evaporation retarders or better, finishing aids. These are being used at rates lower than the traditional 0.20 lbs/sf/hr with IL cement and SCMs. Some parties are recommending applying these evaporation countermeasures as low as 0.05 lbs/sf/hr. Hydration Stabilizing Admixture – an option Hahn RM would have liked to try to see if a delayed set would cause surface crusting or plastic shrinkage cracking. Fresno Trowel – the use of a Fresno is controversial. Some people feel their use will close the surface too early. To me, like a lot of things, it depends on a diligent and experienced finisher to know when to use the correct tools, Fresno or other trowel.   No SCM – In the 1/10/25 Teams call with 25 participants several people stated they wished one of the mixes would have been placed with either only I/II cement or only IL cement, whichever is locally available, to have slabs without SCM’s. Variable Weather Conditions or Late Season – There was discussion about placing in higher evaporation rate conditions or later in the construction season to shorten the time before deicing chemicals are applied. Both could put the slabs in a higher risk situation. Variable Water Cement Ratios – Many state DOT’s will have a water/cementitious ratio around 0.40 for slip form paving / low slump mixes. This is fine for mainline paving but very difficult to hand screed so parking lots can have a w/cm ratio of 0.45 to 0.48 which could  allow snow or chemicals to penetrate into the concrete easier vs mixes with less water, depending on how they are finished and cured. Fly Ash or Natural Pozzolan – In some markets Class F is the only fly ash available. In other markets only Class C is available. Another option is natural pozzolans, made from crushed volcanic rock. Finally, some areas use ash blended into the cement as a IP or a IT with limestone and pozzolan. The graph below from the American Coal Ash Association shows how much the availability of fly ash has declined due to coal fired power plants shutting down or switching to natural gas. From over 70 million tons per year 2002-2008 down to ~28 million tons per year in 2022: Natural pozzolans have filled some of the coal ash availably gap. They tend to have a higher water demand. Think of them as extremely small volcanic aggregates that need the moisture filled inside of them before additional moisture will be shared for hydration. It is similar to saturated surface dry (SSD) aggregate or sand. All of these ashes, natural or man-made will react differently. This should be discussed with your ready mixed producer because each pozzolan will behave slightly differently in concrete set time influence, also depending on the admixtures and if it was introduced as blended cement or from a dedicated batch plant silo. That is a summary of the scaling study in progress and some of the many variables that could be contributing to undesirable pavement outcomes. Please consider if the investment of a few thousand dollars and some time could help clarify which variables will help maintain a high quality, durable concrete pavement surface in your zip code.    Sayde Hindelang Wed, 29 Jan 2025 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:498 https://ascconline.org/Home/News/articleType/ArticleView/articleId/489/Rebar-Constructible-Productive-Detail-Library#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=489 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=489&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/489/Rebar-Constructible-Productive-Detail-Library Reinforcing steel is one of the critical elements of any concrete structure. As structural engineering firms have minimal incentive to provide efficient rebar details and experienced structural engineers retire, concrete contractors and rebar placers would benefit from a library of productive rebar details. The vision is to have a large collection of rebar details which the concrete construction team can propose as substitutes. The Concrete Reinforcing Steel Institute, CRSI, members have embraced this same concept and the CRSI Placing Committee with support from several other CRSI committees, will participate in this project. Initial thoughts are to organize the details by the type of element that are being made more efficient, including: Deep foundations Footings and pile caps Walls Columns Slabs Splices and general details There are some existing resources to provide a starting point. For examples the 26 articles “Detailing Corner” which appeared in Concrete International, 2009-2013, ACI Pro Constructability Blueprint https://www.concreteproductivity.org/constructabilityblueprint.aspx , Five Structure Magazine articles on Recommended Details by Dave Fanella and Michael Mota and ACI 315 Rebar Detailing committee documents. BIM is another tool for showing in 3D the difficulties of existing details and the benefits of a proposed revision. There are “Benefits of BIM for steel reinforced concrete” brochures available from CRSI https://www.crsi.org/reinforced-concrete-benefits/benefits-of-bim/ and ASCC members that can provide 3D rebar detailing services.  What do we need now? Send preferred details from concrete contractors and rebar placers to hernandezm@ascconline.org ASCC volunteers to participate in the project, which can include: Talking with rebar placers and detailers in your local area about providing productive details Attending virtual and in person meetings with CRSI Placing Committee task group Possibly engaging with ACI Committee 315 - Details of Concrete Reinforcement        Having details which have been reviewed by CRSI and ASCC should increase the likelihood of their acceptance on one of your projects. This is another example of how our collective collaboration can improve your bottom line.   Sayde Hindelang Fri, 27 Dec 2024 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:489 https://ascconline.org/Home/News/articleType/ArticleView/articleId/490/December-2024-Guidance-for-Concrete-Contractors34-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=490 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=490&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/490/December-2024-Guidance-for-Concrete-Contractors34-in-a-Series Question:  Our company's regional hub located in South Florida has been selected to furnish and install approximately 100,000 square feet (SF) of reinforced concrete slab on grade (SOG) for a large, privately owned warehouse developer.  Nominal slab thickness is 5 inches, with a 28-day concrete design compressive strength of 3500 psi normal weight concrete (NWC).  Typical slab reinforcing is ASTM A 1064 deformed welded wire reinforcement (WWR), specified in the structural drawing general notes as 6 X 6-D2.9 X D2.9. Preparation of subgrade within the building footprint is to be performed by others.  Based on our company policy, we do not take ownership of a building substrate until the pad has been inspected, tested and accepted by the geotechnical engineer and its location certified by a licensed surveyor. Both of those hurdles were cleared last week. To price the job, our bid team divided the building footprint into 5 equal placement areas of 20,000 SF each. Including waste (and various other arcane estimating fudge factors), our estimators determined by calculation that each slab area requires exactly 325 cubic yards (CY) of concrete to complete. All concrete placements, including those that contain mechanical rooms and other back-of-the-house spaces, require a trowel finish. According to our project schedule, the first order of business after the recent substrate handoff is to furnish and install a layer of 15-mil. vapor barrier, followed by layout and placement of the precast concrete "dobies" that support the sheets of WWR at approximately mid-depth of the slab. Unfortunately, this simple and efficient work sequence that has become routine over the years (and quite profitable--for us, anyway) took a turn for the worse when we received notification that our entire shipment of WWR has been rejected by one of the Owner's representatives. The stated reason for rejection?  "We saw the wire mesh being delivered at the jobsite today. It appeared rusty", the email states. "We are recommending that this material be replaced. Let us know if this is a problem".  A representative photo of our WWR stockpile onsite is shown below. Representative photograph of WWR sheets recently delivered onsite. We are long-standing members of ASCC; members who were active when one of the early Position Statements (Position Statement #3: Coatings that Affect Bond to Reinforcement) was created and published in the ACI Concrete International March 2003 issue--quite likely in response to a similar scenario being revisited today on our project.  To oversimplify enormously, by the March 2003 publication date, the collective industry consensus already was that testing performed to determine effects of form release agents, concrete spatter, and...well...bond breakers applied to the bonding surface of reinforcing steel bars proved that such applications "did not affect the bond for concrete strengths of 4000 and 5000 psi."  We are confident the backup information we already have in hand will be sufficient for the engineer to review, reverse the rejection, and allow us to proceed with installation of the WWR that is currently stockpiled onsite. In addition to ASCC Position Statement #3 and excerpts from ACI documents, our WWR supplier is preparing a submittal from the steel mill explaining why the normal, rusty appearance is not a legitimate cause for concern or rejection. Before we respond to our customer, does the ASCC Hotline have any update(s) to the original Position Statement #3 or any additional backup we can submit to expedite resolution?  We are in a schedule holding pattern while this issue gets resolved. Please advise. ___________________________________________________________________ Answer:  Excellent question; and timely, too. As it turns out, there are several recurring themes and issue updates that can be addressed to help us resolve this Hotline call. We present those in no particular order as follows below. Many concrete contractors can testify that concrete is a natural product that moves--and then behaves--in mysterious ways.  After all, who is there among us that is not dealing daily with at least one of the typical potential costs associated with reinforced structural concrete: shrinkage, curling, deflection, delamination, and--of course--cracking? Although the chemical processes involved in the manufacture of steel products are somewhat more controlled in the steel mills, there are still a few head-scratchers associated with using steel as a building material as well. Consider, for example, the life cycle of steel wire product eventually used to reinforce concrete slabs such as yours. As soon as the final WWR sheet in a particular bundle is placed on a pallet, the bright metal wire instantly becomes fair game for visible rust to develop.  Corrosion experts refer to this first appearance as "flash rust".  The rapid initiation of such flash rust is exactly as its name suggests--it appears in a flash, similar to the predictably spontaneous sprouting of weeds we all notice within minutes after we have finished mowing our front lawns. This process, of course, seems to occur even faster when the steel is exposed to a typically humid South Florida market environment.  Chances are extremely high that all bundles of WWR being shipped to your market will feature a normal coating of flash rust by the time they arrive onsite. For more information regarding the manufacture and use of WWR, you can access the Wire Reinforcement Institute (WRI) Manual of Standard Practice at the link given below: https://www.wirereinforcementinstitute.org/application/files/4416/1711/1814/WWR-500-R-21_MSP.pdf __________________________________________________________________ It could be argued that one of the riskiest predicaments faced by ASCC concrete contractors in their day-to-day work is the scenario whereby rejection of work product (or the assignation of "suspect work" status) is initiated by a project stakeholder with little or no background in concrete construction or relevant experience with any part of the contract work at hand. This problem can be compounded when the author of the suspect noncompliance is relatively high up in the food chain--perhaps even at project Ownership level. We note here that--in your case-- the "rejection document" is really nothing more than email traffic that neglects to contain the most essential part of the noncompliance equation: it does not report exactly what part(s) of the contract document requirements have been violated.  In order for us to determine the contractual quality requirements that govern the reinforcing steel material you are furnishing to the project, we reviewed two of the project specification sections that are part of your construction documents, namely Section 03 20 00 CONCRETE REINFORCING and Section 03 30 00 CAST-IN-PLACE CONCRETE.  In both cases, these construction document specification sections are silent regarding rust, removal of rust and so on.  The reinforcing steel specification does contain a standard requirement that all reinforcing steel delivered to the project be accompanied by mill certifications for Quality Control traceability purposes. We also noted, however, that you are bound by reference to follow ACI 301-20 Specifications for Concrete Construction. ACI 301-20 Section 5.3.7.6 states that rust is one of the material aspects (including efflorescence, stains, surface deposits) that require removal only if specifically called out in the Contract Documents.  On the other hand, ACI 301 section 3.3.1 states "Reinforcement with rust, mill scale, or a combination of both will be considered satisfactory, provided minimum nominal dimensions, weight per foot, and minimum average height of deformations of a hand-wire-brushed test specimen are not less than applicable ASTM specification requirements."  In other words, section 3.3.1 gives a qualified inspector an avenue to determine acceptability via testing, even though the construction documents do not specifically call out locations where rust of any nature must be removed. In your case, the applicable ASTM document is ASTM A 1064 Standard Specification for Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete.  Within this ASTM document, Section 7 Mechanical Property Requirements-Wire, Plain and Deformed specifies testing protocols and tolerance criteria for use in evaluating contract compliance. ___________________________________________________________________ A complicating factor at play here typically presents difficulties for inexperienced (and perhaps even some experienced) stakeholders to wrap their heads around: the fact that seemingly deleterious conditions at first glance (rusted steel, in this case) can in fact be quite helpful.  Such a scenario would not be the first time this curious type of phenomenon has been discussed in an ASCC VOICE Guidance column. Take, for example, the Hotline call described in Guidance installment #9, which appeared in the August 2022 issue of the VOICE. In that episode, the caller wanted to understand the term "bold exposure" that appeared in the project construction documents (this was a term found in the Division 5 structural steel scope documents, not part of the ASCC member's contract scope). On that project, structural members were fabricated with ASTM A 588 steel, which is intended to be corrosion-resistant with high tensile strength. Also known as "weathering steel" or "COR-TEN" steel, this material was specifically developed to rust on purpose for the steel to protect itself from further rust.  This process works just fine if the steel can be "boldly exposed" to an environment that will allow a thin layer (aka "patina") of rust to form on its outer surface. In this case, "bold exposure" is defined as "rain washed-sun dried". It can take several cycles of rain wash and sun dry before the protective oxide layer is fully activated.  Once the steel members have been milled and exposed to ambient air, the surface oxidation process (flash rust) can start within minutes and take up to, say, 6 months to complete. Several state highway departments in the snow belt states specify weathering steel to eliminate initial painting costs and reduce future maintenance and replacement costs--which can be enormous.  Architects often specify weathering steel for sculptures and other exposed steel applications due to its pleasing appearance as well. Here in the San Francisco Bay Area market, weathering steel members can be seen at several above-ground BART stations (e.g. Rockridge, Balboa Park), which are exposed to the environment year-round. _________________________________________________________________ Over this past year, the ASCC Technical Division updated the collection of more than 40 Position Statements.  As can be expected, the update to ASCC Position Statement #3: Coatings that Affect Bond to Reinforcement incorporated more than just 20-plus years of advancements in the field of corrosion science related to concrete and reinforcing steel. It also approached the topic of expectation management as well. For example, the revisions to Position Statement #3 described the reactions some project stakeholders may have upon discovery of corrosion by-products (aka rust) on what has been advertised as "new" materials in the field as follows: "Engineers or inspectors typically direct concrete contractors to clean bars that are coated with materials believed to decrease bond.  Form-release agents, bond breakers and cement splatter sometimes come in contact with reinforcing steel before concrete is placed. In the absence of data concerning the types of materials that decrease bond, cautious engineers and inspectors usually require all such material to be cleaned from the reinforcing. However, two studies have provided test data showing that some of these materials don't decrease bond." For more information, a link to the recently updated ASCC Position Statement #3 is as follows: https://ascconline.org/Portals/ASCC/Files/Position%20Statements/PS-3_CoatingsAffectBond_webSC-1.pdf?ver=gafefyxrnGEEskWnbyjnrg%3d%3d _________________________________________________________________ In addition to the contractual requirement for the concrete contractor to follow ACI 301-20 Specifications for Concrete Construction, the project design team is obligated to follow the requirements for reinforcing steel (including WWR) codified in ACI 318-19 Building Code Requirements for Structural Concrete (aka "the Code"). According to the Code, section 26.6.1.2(b) states "Nonprestressed reinforcement with rust, mill scale, or a combination of both shall be considered satisfactory, provided a hand-wire-brushed representative test specimen of the reinforcement complies with the applicable ASTM specification for the minimum dimensions (including height of deformations) and weight per unit length." This Code requirement is consistent with the inspection and testing protocols for suspect reinforcing material specified in ACI 301-20 section 3.3.1, and Standard Specification ASTM A 1064, both of which are discussed in detail, below. (N.B.: Commentary section R26.6.1.2(b) associated with the corresponding Code section referenced above is of some significance, since it provides a clear description of acceptable rust products exhibited on reinforcing steel as follows: "Research has shown that a normal amount of rust increases bond. Normal rough handling generally removes rust that is loose enough to impair the bond between the concrete and reinforcement."  Translation: "By the time the ironworkers up on the deck have shaken out the WWR sheets, any harmful material has fallen off, leaving whatever incidental rust or rust by-products that remain on each sheet normal and acceptable for use in the work".) ___________________________________________________________________ Based on the above, the best course of action is to request relief from the rejection in writing today, pending receipt of the submittal package currently being prepared by your WWR supplier.  Ultimately it is the WWR supplier's responsibility to deliver the WWR to the jobsite--along with supporting backup documentation--indicating compliance with ASTM, ACI and other appropriate contract documents. In the meantime, your submittal package should include the updated ASCC Position Statement #3, which provides some cover for "cautious inspectors", no matter where they might reside in the project stakeholder food chain.  Barring any test results that indicate otherwise, it appears the WWR as delivered to your project jobsite complies with the contract documents. _________________________________________________________________ Sayde Hindelang Fri, 27 Dec 2024 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:490 https://ascconline.org/Home/News/articleType/ArticleView/articleId/492/Message-from-the-Chair#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=492 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=492&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/492/Message-from-the-Chair Dear Members, As 2024 draws to a close, we want to take a moment to reflect on another incredible year for the Concrete Polishing Council (CPC). Together, we have advanced industry standards, shared knowledge, and strengthened our network of professionals dedicated to the craft of polished concrete. This month, we invite you to celebrate our achievements and prepare for an even more successful year ahead. With new educational resources, upcoming events, and collaborative opportunities, there has never been a better time to be part of this thriving community. Thank you for your continued commitment to the CPC and for being part of this journey. Wishing you and your families a joyful holiday season and a prosperous New Year! Sincerely, Ryan Klacking Chair, ASCC Concrete Polishing Council 2024 Industry Trends and Innovations As we look ahead to 2024, polished concrete continues to gain traction as a sustainable, cost-effective flooring solution. Trends to watch include: Decorative Advancements: Increased demand for stained and stenciled finishes. Sustainability Focus: Products and techniques for reducing carbon footprint in concrete polishing. Technological Integration: Cutting-edge equipment for faster, more efficient polishing. Stay ahead by incorporating these trends into your projects and sharing your experiences with fellow members. Spotlight on Safety Winter weather can pose unique challenges for concrete polishing teams. This month, review your safety protocols for handling equipment in cold conditions and maintaining slip-resistant job sites. For more resources, visit our Safety Center. Concrete Polishing Council Certification Take advantage of any downtime you may have this winter by enhancing your knowledge in polished concrete with a certification as a Concrete Polishing Tradesman or Concrete Polishing Craftsman. Become part of the elite team of installers sharing the same passion of continuing your career with endorsements that can help differentiate your commitment to trade. ASCC members that have a username and password, click here. If your company is an ASCC member, but you do not have a username and password, click here. Non-members must register to get a username and password for access, Click here. Thank you for making the Concrete Polishing Council an essential resource for the polished concrete industry. We look forward to growing together in the years to come. Warm wishes, The ASCC Concrete Polishing Council Team Sayde Hindelang Fri, 27 Dec 2024 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:492 https://ascconline.org/Home/News/articleType/ArticleView/articleId/493/Get-Ready-for-the-2025-Decorative-Concrete-Experience-at-World-of-Concrete#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=493 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=493&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/493/Get-Ready-for-the-2025-Decorative-Concrete-Experience-at-World-of-Concrete Ah, the holiday season. That festive time of year when our thoughts and attention turn to loved ones, friends, thanks for all of our blessings, and the World of Concrete. Wait! World of Concrete? Yes, between holiday parties and family get-togethers we have had our eyes on next month’s tradeshow. Just a few short weeks away and the elves at the DCC and CPC have been busy putting together this year’s Decorative Concrete Experience. After the smashing success of the inaugural Decorative Concrete Experience last year, we have enlarged and upgraded the Experience for 2025. You will find a new, larger booth (S12105) in the south hall, along the left side, by the stairs half way back. A new, expanded timeline on the history of decorative concrete will be joined by a history of polished concrete. From Bomanite and Euclid Chemical we were able to source some of the very first and very latest stamping tools as accompanying exhibits. The DCC’s Decorative Concrete award-winning projects will also be highlighted, showcasing the talents and techniques of the finest craftsmen in the industry. ASCC member Jon Don has not only donated testing equipment for hands-on exhibits in the polishing realm, but they will also have personnel there the entire show to demonstrate and help you learn. Tuesday and Wednesday there will be a series of TED-type talks, twice a day with subjects divided up between decorative and polished topics. Be sure to check the schedule for times, topics, and speakers. Most exciting is that this year the ASCC will take over the Decorative Concrete Hall of Fame, started years ago by Bent Mikkelsen and his Concrete Décor magazine and tradeshow. Previous inductees joined the Hall of Fame at the Concrete Décor Show, and since that show is no longer produced, there have been new additions to the HOF since 2019. To make up for that absence, this year, three new inductees will be announced at a special ceremony in the booth on Wednesday at 3:30. Please plan to attend this very special event and stick around for a “Meet the Legends” happy hour afterwards where the new inductees will be joined by other HOF members for a meet and greet. Of course, this Decorative Concrete Experience not only promotes decorative and polished concrete but ASCC as well. Volunteers will staff the booth to promote ASCC, emphasizing member benefits, answering questions, and signing up new members. Don’t miss out! If you are headed to Vegas next month, make The Decorative Concrete Experience part of your itinerary. Sayde Hindelang Fri, 27 Dec 2024 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:493 https://ascconline.org/Home/News/articleType/ArticleView/articleId/494/Improve-Your-Leadership-to-Improve-Your-Safety-Performance#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=494 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=494&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/494/Improve-Your-Leadership-to-Improve-Your-Safety-Performance Recently I (Charles) was watching my favorite NFL team play our division rival. Our rookie quarterback dropped back and launched a deep pass to an open receiver in the end zone. Instead of hauling in a touchdown pass that would have been caught 90% of the time in the NFL, the receiver dropped the ball. In the postgame press conference, the quarterback took blame for the dropped pass, saying, “The fact that he got to it when I overthrew it was pretty impressive.” Some have called this The Window and Mirror Leadership model. When great leaders have success, they see windows (e.g. “we have a great team”), and when they face failure, they see mirrors (e.g. “I should have done something differently.”). At Caterpillar Safety Services, when we say LEADERSHIP is one of the key, interdependent components of a resilient safety culture, we’re talking about the specific things leaders say and do to establish and reinforce safety culture. In my work as a safety culture and leadership consultant, every leader I meet says that they want to keep their people safe. However, when I interview frontline employees, I hear many reports of leaders who focus only on production and efficiencies, or say nothing at all about safety, leaving their team wondering how important safety really is to their leader. Here are four areas in which great leaders are using words and actions to proactively shape a resilient safety culture: Pursue accountability Proactively I’ve heard leaders boast “I’m not afraid to tell my team when they screw up!” But great leaders don’t wait until something negative happens to measure performance and provide feedback. Rather, great leaders define clear expectations early, equip their people with training and resources, regularly observe performance, and continuously provide feedback. They frequently reinforce preferred behaviors with positive recognition. If missteps occur, they get curious and provide coaching or systematic support so the circumstances can be corrected before something more serious happens. I ask workshop participants, “If my 17-year-old comes home five minutes after curfew and I say nothing, what happens next?” Everyone laughs. We all know that if I say nothing, he might come home even later the next night. “What if he comes in five minutes early? What should I do then?” I ask. Because I’ve been talking to them about accountability, they know that the right answer is that I say something, because I want him to know that I’m paying attention to his performance. It’s this constant feedback, steering him into the right behaviors, that help us avoid larger errors. On the job site, inattention to detail and the absence of real-time feedback can lead to significant injury or damage. Create Connections Between the People They Lead The leaders I work with are busy, and frequently they supervise worksites stretching over dozens of square miles (or more!). They simply cannot have their eyes on everyone, everywhere, all the time. And that’s why great safety leaders are proactively building connections with their teams, touch points that generate confidence in the culture and motivate safe behavior even when the boss isn’t around. And it’s not just building relational connections. It’s also connecting safety to every facet of the operation so there is no decision, operation or process completed that excludes safety considerations. If we say “be safe” at the beginning of the shift, then we need to reinforce that message throughout the day with conversations that keep safety at the forefront. Demonstrate Commitment to Safety by Continuously Growing Credibility In 1945, the doubling rate of information was estimated to be around 25 years. Today, it’s estimated to be at 12 hours. And new AI technologies will only increase the speed at which we acquire new information about our processes.  What does that mean for a leader? It means that what you need to know to maintain your credibility is constantly growing, so leaders must commit themselves to continuous learning – in leadership, process, quality, all facets of the operation. I once had a workshop participant bravely raise his hand and ask, “What if I’m tired of learning new things?” If that’s true, it’s probably time for him to retire, because leaders must continually grow their knowledge and skill set to maintain credibility and guide people effectively. A great way to combine connectivity with credibility is to initiate safety learning from the experts in your business – the frontline employees who work amid hazards every day. Build Trust with The Teams They Lead You don’t build trust by force of personality or by simply showing up. I imagine trust as a bank account. You make deposits by expressing individual care and concern for an employee (and their family), when you follow through on your commitments, and when you live out your values – especially when it costs you something. You withdraw from the account when you neglect to do these things or make decisions that adversely affect an individual. Imagine your “trust accounts” with your team. Where do you stand? Are you making regular deposits into the trust account? Or is your account in the red? What specific actions are you taking to bring the balance of trust to your favor? Effective safety leaders who are building a resilient safety culture aren’t just crossing their fingers, hoping the right kind of people come along who will make the culture great. Rather, they’re intentionally saying and doing things to create the preferred culture. It was no accident that the rookie quarterback took the blame for a bad pass that never was. Instead, he was intentionally shielding his teammate and proactively working to create a culture where we don’t point blame when things go wrong. He was building trust with the receiver – and the rest of the team. He was choosing to be a great leader. Written by: Charles Dean ll and Kris Nagy  Sayde Hindelang Fri, 27 Dec 2024 13:30:00 GMT f1397696-738c-4295-afcd-943feb885714:494 https://ascconline.org/Home/News/articleType/ArticleView/articleId/488/Updates-from-the-CPC#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=488 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=488&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/488/Updates-from-the-CPC Greetings, CPC Members! As the year draws to a close, we’re excited to bring you the November edition of the CPC newsletter. This month’s issue is packed with valuable insights, events, and updates designed to keep you connected and informed in the concrete polishing industry. Industry Updates 1. Innovations in Polished Concrete Sealants The latest sealant technologies are not only enhancing durability but also improving sustainability. These innovations are transforming polished concrete surfaces, offering better protection, and reducing environmental impact. 2. Safety Spotlight: Ergonomics in Concrete Polishing Long hours and heavy equipment can take a toll on your team’s well-being. This month, we’re highlighting ergonomic solutions to reduce strain and injury risk during polishing operations. From adjustable machinery to advanced protective gear, learn how to keep your workforce safe and efficient. Upcoming Events -World of Concrete 2025 – January 21-23, 2025 The Decorative Concrete Experience Location: South Hall Booth S12105 Presented by: The Decorative Concrete Council (DCC) & the Concrete Polishing Council (CPC) Sponsored by: ASCC, DCC, and CPC Brace yourselves! The DCC and CPC are teaming up to bring you the DCC/CPC Experience at the 2025 World of Concrete—an action-packed, interactive zone where you can dive into the dynamic world of decorative and polished concrete! What’s in Store? Get hands-on knowledge with live, short peer-to-peer presentations from top industry experts. Whether you're a seasoned pro or just getting started, these sessions are designed to boost your business and elevate your skills! But that’s not all! This year, the ASCC is presenting the latest inductees into the Decorative Concrete Hall of Fame—a prestigious honor founded by Concrete Décor Magazine and now run by the ASCC’s Decorative Concrete Council. Exciting Highlights: A Journey Through History: • The Evolution of Decorative and Polished Concrete: Explore a captivating timeline showcasing how these art forms—and the DCC and CPC—have transformed over the years. • Meet the Legends: Don’t miss the chance to learn from the pioneering artisans who built this industry. Engage in live sessions and get inspired by the stories behind their iconic work! 2024 DCC Award Winners Spotlight: • Relive the most incredible projects of 2024 with a visual showcase of the winning designs. • Meet the DCC winners in person! Chat with the design teams as they reveal how they tackled challenges and brought their award-winning visions to life. Decorative Concrete Hall of Fame Ceremonies: • Award Presentation • Inductee Speeches—hear directly from the newest legends of the craft! Concrete Polishing Luncheon & Open Forum Tuesday, January 21 | 11:30 AM - 1:30 PM Registration Fee: $120 (Early Bird) | $155 after 12/12/24 Use this ASCC Code for a discount on your registration badge: A20 Presented by: World of Concrete & ASCC Concrete Polishing Council Get ready for an electrifying event at the World of Concrete! The Concrete Polishing Council (CPC) of the ASCC is rolling out an exclusive opportunity for polishing pros to gain invaluable insights directly from the industry’s top experts. The CPC has released three brand-new, contractor-focused documents—a game-changer for anyone navigating today’s challenges in the concrete polishing field. These authoritative consensus papers are packed with practical solutions and strategies designed to elevate your projects and boost profitability! Why You Can’t Miss This Event: Learn From the Best: Meet the brilliant minds behind these documents and dive deep into how you can put their expertise to work for you. These sessions are your chance to get the inside scoop on maximizing the impact of these groundbreaking position papers! Polishing Panelists: Panelists Announced Soon! Stay tuned for the reveal of our expert lineup—get excited for a powerhouse panel that’s ready to share their secrets for success! Limited Spots—Register Now! Don’t wait—secure your place at this must-attend luncheon and forum before prices go up! It’s time to take your concrete polishing knowledge to the next level and connect with the best in the business. See you there! Additional Experiences: • Discover the extensive resources that ASCC, DCC, and CPC provide to grow and support the industry. Thinking about joining? Now’s your chance! • Myth-Busting Sessions: Get the real facts on polished and decorative concrete. • Take a Self-Guided Tour of the Decorative Concrete Hall of Fame and explore the art and stories that shaped this incredible industry. Don’t miss this incredible opportunity to learn, connect, and elevate your concrete game. See you at the booth! Get Involved and Make a Difference! Your expertise and passion drive the CPC forward. Here’s how you can get more involved: • Become a Mentor: Share your knowledge and help guide the next generation of concrete polishers by joining our mentorship program. It’s a rewarding way to give back to the community while developing leadership skills. • Join a Committee: We are actively seeking members for our Technical Standards and Membership Engagement Committees. Your voice can shape the direction and growth of CPC initiatives. Thank you for your continued support and active participation in our community. Together, we are paving the way for a thriving and innovative concrete polishing industry. Wishing you a productive and successful November! Best regards, Ryan Klacking CPC Team American Society of Concrete Contractors Sayde Hindelang Tue, 26 Nov 2024 21:19:00 GMT f1397696-738c-4295-afcd-943feb885714:488 https://ascconline.org/Home/News/articleType/ArticleView/articleId/487/Supporting-Suicide-Prevention-through-CIASPs-Giving-Tuesday-Initiative#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=487 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=487&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/487/Supporting-Suicide-Prevention-through-CIASPs-Giving-Tuesday-Initiative As members of the American Society of Concrete Contractors (ASCC), our dedication to workforce well-being encompasses both physical safety and mental health. A pivotal partnership in this endeavor is with the Construction Industry Alliance for Suicide Prevention (CIASP). Given the concerning statistics surrounding suicide rates in construction, CIASP's mission to provide resources, education, and support is more vital than ever. Serving on CIASP's Education and Finance Committee, I've witnessed the profound impact of these initiatives on our industry. Each year, CIASP spearheads the "Giving Tuesday" campaign, a Global Day of Generosity occurring on the Tuesday following Thanksgiving. This initiative offers individuals and organizations a meaningful opportunity to contribute to CIASP's ongoing efforts. Funds raised during this event are essential for sustaining outreach programs, developing educational materials, and conducting training sessions that equip companies and workers with the necessary tools to support mental health and prevent suicide. At ASCC, we encourage all members and partners to support CIASP's Giving Tuesday campaign. Every contribution, regardless of size, plays a crucial role in advancing initiatives that foster safer and more supportive environments within construction workplaces. By uniting on this day, we can demonstrate the strength of a collective industry response, underscoring our commitment to the holistic well-being of our workforce. To participate in this impactful cause, please visit CIASP's website at www.preventconstructionsuicide.com. Together, let's make a lasting difference in the lives of our colleagues and build a healthier, more resilient industry. Sayde Hindelang Tue, 26 Nov 2024 21:16:00 GMT f1397696-738c-4295-afcd-943feb885714:487 https://ascconline.org/Home/News/articleType/ArticleView/articleId/486/Crush-Your-Next-Presentation#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=486 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=486&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/486/Crush-Your-Next-Presentation What does a presentation have to do with decorative concrete?  Well, a presentation can be defined many ways. It isn’t necessarily just a speech in front of a group of strangers. It could be your first sales call or employee meeting.  Maybe you have to offer decorative options to a H.O.A. or explain your quote to a group of decision makers. Or, the ASCC has asked you to conduct a seminar for the very first time. Honing your speaking skills makes you a better business owner or more valued employee. Whether you are a seasoned speaker or a first timer, there are some time-tested tips to help you crush that presentation It helps to practice but don’t worry about being perfect, no one is, just be yourself. Try to master your subject. Maybe you already have through experience. If not read up and research. As the adage goes, you never stop learning and deep knowledge can be sensed by your audience. It also boosts your confidence Like some of the winningest athletes, use a visualization exercise. Imagine yourself standing confidently in front of your audience. See them smiling and nodding. Visualize a positive response, or that group of decision makers saying yes to your proposal. Remember those feelings of accomplishment and confidence as you begin your presentation. Engage your audience. Make sure your content is relevant and valuable. Start with a compelling story, and interesting fact, or a rhetorical question to get them thinking. Show your energy and compassion! Be enthusiastic, it’s contagious. Your excitement will energize the audience. Watch your body language. Use open gestures, smile (its contagious too). Establish eye contact with as many as possible. If you are giving an online presentation, I have found it helpful to stand as I speak even though no one can see me. Breathe. Before you start, take a few deep breaths, hold for a second, and exhale slowly through your mouth- it helps calm the nerves. Avoid caffeine prior to the engagement. It’s a stimulant and will increase anxiety and nervousness. End with impact. Have a strong closing statement, a call to action, or an inspiring quote. You want to leave the group with something to think about or act upon. It difficult to imagine any skill that impacts a business more than the ability to give a presentation. Negotiating, sales, hiring, training, managing, leading, are all done better by someone who seems calm, cool, and confident.  Understanding that no one is born with superior speaking or sales skills, but like most other aspects of our professional careers, they are learned and then honed with practice and experience, makes it easier to add this to your list of self-improvement goals. Sayde Hindelang Tue, 26 Nov 2024 21:13:00 GMT f1397696-738c-4295-afcd-943feb885714:486 https://ascconline.org/Home/News/articleType/ArticleView/articleId/484/Ongoing-Interior-Slab-Mix-Collection-with-IL-Cement-Study-by-ASCC-ACI-302#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=484 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=484&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/484/Ongoing-Interior-Slab-Mix-Collection-with-IL-Cement-Study-by-ASCC-ACI-302 This month the Technical Director’s Message will revisit the ongoing Interior Slab Mix Collection research project. Hundreds of newer IL cement mixes and historic I/II cement-based mixes are still needed for an artificial intelligence (AI) platform to look for patterns between the I/II and IL mixes that are performing well. The guidelines are meant to help contractors transition to successful IL mixes and provide talking points to collaborate with ready mixes producers on optimizing mixes. Collaboration is one of the strengths of ASCC, let’s work together on solutions to this complex challenge. Some members have stated they are not placing interior non-air slabs. Regional ASCC advocates are also needed to talk with local ready mixed producers and ask for 2017-2022 interior SOG mix designs, prior to the IL rollout. Every ready producer will have numerous mixes like this. Surveys collected in 2023 indicate many concrete contractors have had issues with interior slab mixes using ASTM C595 Type IL cement, while many others (~50%) report no new issues. Contractors requested through ASCC and ACI meetings that there be a project to collect concrete mixes and cement mill certificates from across the country to attempt to discover what is fundamentally different between the mixes performing well vs those that are not. This investigation will be across all lower 48 states and 8 NRMCA regions with a goal of 1,000 mixes collected (600 IL and 400 I/II or II/V). Analysis will be performed by an artificial intelligence, AI, platform and validated by industry experts. A report to follow with a list of regional strong and weak correlations of changes likely to help improve the mix and what is not likely to improve the mix performance. Note that an expert SOG consultant will be better at looking at one specific mix than any analysis looking at trends in hundreds of mixes. ASCC can provide a list of expert consultants if needed. The appeal was sent to ~300 ASCC contractors and ACI 302 members requesting SOG mixes. In addition to 2023 - 2024 mixes with IL cement the request was made for mixes with I/II (or II/V) cement concrete, to establish a baseline for the AI of state of the industry prior to the wide production of IL cement. If you would like to participate, please send submittals to mhernandez@ascconline.org  Please send: 3000 to 5000 psi, non-air entrained, normal weight concrete slab mixes. The information needed is: • Mix Proportions • Cement Mill Certs • Aggregate Gradations • Admixture names If you submit a IL mix you will also be asked to fill out a survey of up to six questions on its performance using this link: Mix Study Survey Sayde Hindelang Tue, 26 Nov 2024 20:38:00 GMT f1397696-738c-4295-afcd-943feb885714:484 https://ascconline.org/Home/News/articleType/ArticleView/articleId/483/November-2024-Guidance-for-Concrete-Contractors33-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=483 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=483&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/483/November-2024-Guidance-for-Concrete-Contractors33-in-a-Series Question: We were recently declared the lowest responsible bidder on a reinforced concrete mid-rise municipal building project that features varying amounts of reinforcing steel congestion in the walls that comprise the building's structural frame.  Our estimating team bid the job assuming all walls will be formed on both sides and placed from above using the so-called "form-and-pour" method of concrete placement. At the elevator core shear walls, for example, we plan to solve the worst congestion problems with self-consolidating concrete (SCC), proportioned with half-inch coarse aggregate and placed with a concrete boom pump.  At other locations, however, the walls are only "lightly congested"--with forming and concrete placement methods yet to be determined. After the bids had been opened and the bid forms were examined, we could see the shotcrete placing method was not mentioned in any of the bid forms submitted by us--or by our competitors. But--now that we have the job--we are having second thoughts. Our in-house shotcrete division manager was given an "Issued for Construction" set of structural drawings yesterday. He reviewed the structural details for the walls, and swears all the walls on this project can be successfully shot as long as the shotcrete placing crew provides a limited amount of supplemental vibration to assist with concrete consolidation in the most congested sectors of the walls--typically found at wall end boundary elements--and around openings that require trim steel. Aside from the wall ends and large blockouts, the walls (aside from the elevator core) are typically reinforced with double curtains of #5 bars, 12 inches OCEW (on center, each way).  In other words, much of the square footage of each wall is a target-rich environment for shotcrete placement. Since the construction documents are silent regarding shotcrete, our company owner asked us to submit a proposal to the design team to place certain walls with shotcrete; with the understanding that our supplemental vibration techniques will be demonstrated with preconstruction mockup panels and then used for effect once the project walls go into production. Based on our limited contact with the design team during the pre-bid process, we have the impression that they have not worked with shotcrete on previous projects. We only had a very short time to do the takeoffs and estimates for what was shown on the drawings. Unfortunately, there just wasn't enough time to consider alternates and float the idea up the stakeholder (and competitor) food chain with pre-bid RFI's. Does the ASCC Hotline have any information available that we can submit to the project stakeholders to support our proposal? We wish to submit a draft of our plan--including the shotcrete mix designs and an adjusted baseline schedule--in advance of the first construction kick-off meeting to be held at the jobsite two weeks from now. We believe our plan--if accepted--will shave about 3 weeks from the project schedule. Answer: As it turns out, there is convincing industry backup to support your proposed plan to utilize the "shotcrete with limited supplemental vibration" process of concrete placement.  First, no matter what method of placement is used to cast the concrete in place (e.g. "form-and-pour", shotcrete, belt, bucket, Georgia buggy, whatever), ACI 309R-05 Guide for Consolidation of Concrete, section 7.4 describes one method of providing supplemental vibration to assist in the consolidation of concrete in congested areas, namely by touching the exposed reinforcing steel bars with a vibrator. This can be helpful--as long as the concrete is still in a plastic state--as described below: The suggested technique (above) of using a form vibrator to accomplish consolidation will not work in your situation, since you will only be backforming one side of each wall.  As we will see, supplemental vibration techniques used in conjunction with shotcrete require a certain amount of careful artistry on the part of an experienced vibrator operator, coupled with the appropriate pencil-type vibrator and close coordination with the nozzleman. In addition to ACI 309 section 7.4 (above), a second industry document we recommend you use to support your plan is an article written by fellow ASCC member (and experienced shotcrete nozzleman) Oscar Duckworth titled "Can Supplemental Consolidation Extend the Limits of Shotcrete Placement?" ("Shotcrete" Magazine's "Shotcrete Corner", published by the American Shotcrete Association (ASA) in their Fall 2018 quarterly issue).  A link to Duckworth's ASA article is given below: https://shotcrete.org/wp-content/uploads/2020/05/2018Fal_ShotcreteCorner.pdf It seems that the vibes you detected from your initial limited contact with the project licensed design professional (LDP) indicate that--in general--the shotcrete process of casting concrete walls in place is relatively new to them. ASCC member Hotline callers have also reported to us over the years that LDP inexperience with shotcrete seems to be a hurdle preventing wider use of the process in their particular geographic construction markets as well. In that case, Duckworth's article would be an effective document to submit because it not only addresses the immediate topic of supplemental vibration but also presents a crisp and informative recap of the shotcrete process itself--as viewed through the lens of an experienced shotcrete nozzleman--complete with examples and photographs of shotcrete test panels with degrees of reinforcing steel congestion that make them prime candidates for supplemental mechanical vibration. Here are a few selected excerpts--some paraphrased by the Hotline--from Duckworth's ASA Shotcrete Magazine article: "Shotcrete is a high-velocity concrete placement method.  In thicker concrete sections with heavily congested reinforcement, the impact velocity is significantly reduced as the material travels through the outer layers of reinforcement. Thus, to provide the consolidation needed to fully encase the reinforcement and compact the concrete, many contractors will use a small pencil-type vibrator with a frequency range of 10,000 RPM (or above) to achieve complete consolidation." "Since freshly placed shotcrete can be easily damaged by vibration, the material must be placed as tightly as possible through proper nozzling techniques.  Simply put, the mechanical vibrator is used only to assist--rather than serve--as the primary means of consolidation.  The material must be carefully placed with vibration used only to help consolidate any remaining small voids or shadow areas behind obstacles." "Skilled shotcrete operators focus the vibrator activity only within discrete areas, working carefully to avoid movement of the in-place material outside the vibrator's radius of action. If operated carelessly, vibrators can damage in-place work. Because material being vibrated is not retained within the formwork, over-vibration can cause the fluidized material to flow downward and outward; which can result in cracks, reduction in internal cohesion, or possibly break the bond between the shotcrete, the reinforcement, or the underlying material." "The use of a mechanical vibrator as a supplementary means to consolidate shotcrete can be an extremely valuable tool to counteract the natural limitations of the shotcrete placement process in congested structural concrete.  The key here is that experienced personnel--and properly chosen vibration equipment--must be paired up with high quality nozzling practices." In addition to the above, we suggest you consider including the relevant shotcrete excerpts from the current ACI Code--e.g. ACI 318-19 Building Code Requirements for Structural Concrete--which incorporated the shotcrete process of casting concrete in place during the last (2019) Code cycle. (ACI 318-19 Chapters 4 and 26, for example, contain most of the relevant shotcrete Code requirements.) In previous years, the ACI 318 Code series had been silent regarding shotcrete; project LDP's had to rely on the IBC (International Building Code section 1908) for shotcrete requirements needed for designs, preconstruction mockups, inspection and acceptance. ASCC Hotline callers that work in markets where shotcrete use is now routine can tell you that the incorporation of the shotcrete Code requirements (from IBC to ACI 318) certainly played a role in bringing the shotcrete process to the attention of designers, Owners, and local government jurisdictions who otherwise had only limited previous shotcrete exposure--if any at all. Hopefully, your plan will be accepted and give you a great opportunity to showcase the benefits the shotcrete process can bring to a project. _____________________________________________________________ Question:  We understand that ACI Committee 318 will be publishing a revised Building Code for Structural Concrete in 2025 that will feature changes to the compressive strength test cylinder protocols specified for use in determining acceptance of concrete--specifically the smaller 4 X 8 in. cylinder size specified in ACI 318-19, Chapter 26.  What can the ASCC Hotline tell us about the expected Code changes? What exactly are such changes, and what is driving them? Answer: You are correct. As it turns out, the 4-inch diameter compressive strength test acceptance cylinders are not without their share of controversies, some of which date back to the early 1970's. The latest--and perhaps the final--controversy appears to be nearing resolution when the ACI 318-25 version of the Code is formally issued. For now, we have to depend on the "public comment" version of the proposed ACI 318-25 Code, which was advertised by ACI and reviewed by the public over this past summer as described below.  Here's the story. (N.B.: The current version of "the Code" is titled ACI 318-19 Building Code Requirements for Structural Concrete.  When released next year, part of the title will simply be revised to reflect the year of publication e.g. "ACI 318-19" will be updated to "ACI 318-25"). As defined in the current Code, ACI 318-19 section 26.12.1.1, compliance requirements for evaluation and acceptance specimens are as follows: "Evaluation of hardened concrete shall be based on strength tests. A strength test is the average of the compressive strengths of at least two 6 X 12 in. cylinders or at least three 4 X 8 in. cylinders made from the same sample of concrete..." What is the rationale behind the requirement for three 4-inch cylinders? Why not two?  According to the companion commentary (e.g. ACI 318-19 section R26.12.1.1(a)), "The cylinder size should be agreed upon by the owner, licensed design professional, and testing agency before construction. Testing three instead of two 4 X 8 in. cylinders preserves the confidence level of the average strength because 4 X 8 in. cylinders tend to have approximately 20 percent higher within-test variability than 6 X 12 in. cylinders." During this last 6-year long ACI Code cycle, hundreds of changes to the Code were proposed and balloted by almost twenty ACI 318 subcommittees. A draft version of the proposed ACI 318-25 Code was then advertised by ACI for a 45-day public review and comment period (from 19 May to 2 July 2024).  The revised section 26.12.1.1 that appeared in the public comment draft version now states " A strength test is the average of the compressive strengths of at least two 4 X 8 in. or two 6 X 12 in. cylinders..." The rationale explaining the proposed change from three 4 X 8 in. cylinders to two appears in the draft version of future ACI 318-25 companion commentary section R26.12.1.1(a) as follows: "Recent test data including cylinders prepared in the field, indicate the difference between the within-test variability of tests of 4 X 8 in. cylinders and 6 X 12 in. cylinders is not statistically significant...Accordingly, the Code now permits the use of at least two cylinders for a strength test for either 4 X 8 in. or 6 X 12 in. cylinders." To date, the Hotline has not heard of any persuasive public comment objections (aka "negatives") to the proposed reduction in number of 4 X 8 in. test cylinders described above. Barring unforeseen events, then, it appears the change from three to two 4 X 8 in. cylinders should be accepted, codified, and become effective when the ACI 318-25 Code document is officially released by ACI. The publication dates are currently slated for January 2025 on the ACI 318 PLUS platform and in hard copy (paper) format to follow in February or March. ________________________________________________________________ Question: Early this year, our company was awarded the reinforced concrete portion of a public works project located just west of the Washington, D.C. metropolitan area.  All compressive strength compliance testing for the structural concrete in our scope (e.g. spread footings, grade beams, walls, columns, slabs on ground, and elevated slabs) is by others--a local testing and inspection agency that reports to the Owner's construction manager (CM). According to our construction documents, the nominal design compressive strength for the structural foundation elements (spread footings and wall footings) is specified as 5000 psi at 56 days. Given that particular strength class, the required testing protocols are listed in our project specifications as follows: Test specimens must be prepared and handled per ASTM C31/C31M: Standard Practice for Making and Curing Test Specimens in the Field. Test specimens must be tested per ASTM C39/C39M: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. Compressive strength cylinders are to be tested for acceptance at 56 days. Each set of test specimens consists of 7 each cylinders, tested as follows: 1 cylinder at 7 days, 2 cylinders at 28 days, 3 cylinders at 56 days, and 1 cylinder held in reserve. Applies only when specimens are 4-inch dia. by 8 inches in length. Each set of test specimens consists of 6 each cylinders, tested as follows: 1 cylinder at 7 days, 2 cylinders at 28 days, 2 cylinders at 56 days, and 1 cylinder held in reserve.  Applies only when specimens are 6-inch dia. by 12 inches in length. (Not used on this project). Frequency of sampling is one set for every 50 cubic yards (CY), each mix, each day; or one set for every 2500 square feet (SF) of wall or slab surface area.  For structural column concrete, every truck load must be sampled. (Note:  regarding the choice of test specimen sizes; who gets to choose?  According to ACI 318-19 Commentary section R26.12.1.1(a), "The cylinder size should be agreed upon by the Owner, licensed design professional, and testing agency before construction." In other words, the concrete contractor is not in that particular decision loop). Placement of the foundation concrete on our project began about 2 months ago. Now, here we are--some two months after our first foundation concrete placement--and the 56-day acceptance compressive strength cylinder test results are starting to come in. This latest batch of Owner agency test reports features two items of concern for us. The first item of concern is the statement that appears in bold at the bottom of each report: "NOTE: LOW TEST RESULTS".  Over the years, of course, our company has received compressive strength test reports on certain projects indicating apparent low breaks. It is fair to say this scenario is routine--an event to be expected, in fact--and certainly no reason for panic waves to ripple all up and down the stakeholder food chain. A recent article that explores this topic in great detail appeared in the February 2022 issue of ACI Concrete International. Titled "Expect Compressive Strength Test Results Less Than Specified Strength on Every Project", the authors explain the statistical basis behind the methodology used to evaluate compressive strength test results and determine contract (and Code) compliance.  Authored by a team of ASCC members, the article is available on the ASCC web page at this link: https://ascconline.org/Portals/ASCC/Expect-Compressive.pdf The second item of concern is the methodology used by the test agency to calculate and evaluate those results; and then from there--determine compliance. The Code compliance requirements listed in ACI 318-19 section 26.12.3.1 (see below) are straightforward enough.  Tabulating and maintaining a "running average" strength test result spreadsheet is a relatively simple matter for our project engineer to track at the job site.  But the test agency on our project has thrown a curve ball on their test reports by adding an extra data column that takes the actual rounded compressive strength test result and then reduces that actual value by 5 percent. See last column in the test report table below titled "*Compr. Str. Reduced by 5%". In this case, the actual rounded compressive strength of 5050 psi is reduced by 5 percent to 4798 psi. Evidently, the testing agency is reducing (aka "de-rating") the actual strength value simply because 4-inch by 8-inch cylinders were used. In other words, if the test specimens were molded in 6-inch by 12-inch cylinders, the actual, unreduced compressive strength test result would be reported and used to determine compliance.  We have not heard of this methodology before, and do not see such a strength reduction factor in the Code.  In fact--just the opposite--as stated in the ACI Code Commentary section R26.12.3.1, shown above.  If the difference in cylinder sizes is "not considered to be significant in design", why would the 4- inch cylinder values need to be reduced once the job moves from design to construction? Please advise.  Answer:  Great question.  The short answer is that this is simply a classic example where local government ordinances overrule requirements given in ACI Codes and Specifications. As noted above, the Owner's test agency is applying the 5 percent strength reduction factor to comply with local jurisdictional requirements. In your case, the "jurisdiction" is a governmental (County level) entity administered by the Critical Structures/Commercial Building Branch of the Fairfax County, Virginia Building Division. The so-called "5 percent rule" governing the use of 4-inch by 8-inch cylinders is presented in a document prepared by the Fairfax County Critical Structures (FCCS) Branch titled "Special Inspections Program (SIP)" in Section 704 Concrete Testing thusly: "Test results must be de-rated by 5%; i.e., nominal results must be multiplied by 0.95 to obtain the final results."  The FCCS SIP Program has been made--by reference--an integral part of your project construction documents. Although the ASCC Technical Division is familiar with the stringent FCCS protocols and requirements associated with the erection and removal of formwork and shoring in Fairfax County, this was our first exposure to the "5 percent rule" per se. But ASCC Hotline callers know full well that several ACI documents (ACI 117, ACI 318, and others) remind the readers straightaway that the LDP is free to confect specifications and compliance criteria that are more stringent than the traditional and customary "industry standards". At the same time, of course, it is always the concrete contractor's responsibility to detect the "tighter" specification language clauses and carve-outs and to consider their implications before estimating and pricing the work--and certainly to rinse such items out before signing any binding construction contract. _________________________________________________________________ Background notes: As all ASCC Hotline callers know, concrete is a natural product with its fair share of idiosyncrasies and controversies. Based on a recent literature survey regarding the 4 X 8 in. cylinders, we drilled deep below the weeds and found the following information worth passing along... Compressive strength testing is hardly a cut-and-dried proposition. After all, the only way to know the true compressive strength of concrete is to compress it. In the U.S., compressive strength testing for acceptance is done with either 4 X 8 in. or 6 X 12 in. cylinders. In the U.K., such testing is done with either 4 in. or 6 in. square cubes (100 or 150 mm). Studies have shown that 2 in. square cubes break up to 15 percent higher than 6 X 12 in. cylinders.  On the other hand, 4 X 8 in. cylinders have been reported to break higher than 6 X 12 in. cylinders as well, up to 4 percent higher. One normalweight concrete 4 X 8 in. cylinder weighs about 9 lbs., while one normalweight 6 X 12 in. cylinder weighs about 30 lbs. Proponents of the 4 X 8 in. cylinders say the smaller cylinders result in less wear and tear on the compression test equipment.  If a cylinder stress of 5000 psi is required, for example, the 6-inch cylinder would have to be loaded to 141,500 lbs., while the 4-inch cylinder would only have to be loaded to 63,000 lbs. On the other hand, opponents say the lighter cylinders could be subject to mishandling and abuse on the construction site; and that the smaller cylinders will be no cheaper since many test agencies charge a unit rate per cylinder, no matter what its size and no matter if the specimen actually ever gets tested. The protocols for compressive strength test cylinders are given in ASTM C31 Standard Practice for Making and Curing Test Specimens in the Field. ASTM C31 section 6.1 tells us "the number and size of cylinders shall be as directed by the specifier of the tests.  In addition, the length shall be twice the diameter, and the cylinder diameter shall be at least 3 times the nominal maximum size of the coarse aggregate". Furthermore, if the purpose of the cylinders is acceptance testing for specified compressive strength, cylinders shall be 6 by 12 in. or 4 by 8 in. The key takeaway from the above ASTM C31 excerpt is the limit on coarse aggregate size, since this excludes any mixes that feature 1 1/2-inch coarse aggregate. In some cases, state highway departments and other regional jurisdictions limit the use of 4-inch cylinders to mixes that are proportioned with 1-inch maximum coarse aggregate size. _________________________________________________________________ Ray Hefner Mon, 25 Nov 2024 15:57:00 GMT f1397696-738c-4295-afcd-943feb885714:483 https://ascconline.org/Home/News/articleType/ArticleView/articleId/475/Guidance-for-Concrete-Contractors32-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=475 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=475&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/475/Guidance-for-Concrete-Contractors32-in-a-Series Question: We are working on a City-funded seismic retrofit project designed to strengthen a large, existing (E) 7-story reinforced concrete mid-rise building. We understand the original structural concrete frame was cast sometime during the mid 1940's. Part of our contract scope includes installing full height reinforced concrete jackets that encase all existing (E) interior concrete columns and thickening the (E) concrete shear walls surrounding the vertical transportation (e.g. stair/elevator) core. Retrofit work--if any--at the foundation level or elevated CIP (cast-in-place) decks at the upper levels is not in our current contract scope. By design, all concrete column and wall retrofit jackets are specified to be cast in place using the shotcrete placement method. The specified concrete surface preparation requirements for the new wall jackets include mechanical roughening of the entire (E) wall contact surface to a quarter-inch amplitude, chipping a grid network of beveled shear keys (2 inches wide, 6 inches long, and 1.5 inches deep nominal, each key), and installing drilled and epoxied, hooked dowels at 12 inches on center each way.  One of the engineers told us the epoxy dowels were designed for shear transfer between the new jackets and the (E) concrete walls.  In addition to shear transfer, each drilled dowel features 135-degree hooks; shown in drawing details capturing the jacket reinforcement curtains at vertical/horizontal bar intersections as well. (N.B.: On background...Prior to bid time, our estimator attended a mandatory prebid conference/job walk hosted by the City and the Public Works design team.  In addition to bidders representing the structural concrete and MEP trades (Mechanical, Electrical, Plumbing), representatives from several testing and inspection agencies looking to bid the job were in attendance as well. The licensed design professional (LDP) explained that the architect had scoured the City archives for information regarding the original building design and construction. As it turned out, the original architect, LDP and contractors of record were no longer in business.  The architect's investigation included a visit to the resident building engineer's basement office to see if there was an old, rolled-up set of original blueprint drawings hiding somewhere; and several hours spent scrolling through microfiche archives at the City Public Works headquarters--all to no avail).  The structural portion of the architect's fact-finding effort included a visual condition survey conducted after the building had been cleared of its tenants. We were advised the design team investigators referred to ACI and ASTM protocols: for example, ACI 201.1R-08 Guide for Conducting a Visual Inspection of Concrete in Service and ASTM C823-12 Standard Practice for Examination and Sampling of Hardened Concrete in Constructions.  Since the visual condition survey turned up no apparent signs of distress or serviceability issues in the as-built condition, destructive testing was deemed unnecessary (e.g. petrographic analysis, cores, and so on). Using information learned at the prebid conference and supplemented in the project ITB (Instruction to Bidders), our estimator prepared a preliminary work schedule based on the following assumed five-step activity sequence: (1) Bush-hammer wall contact surface to the required amplitude; (2) Lay out and chip new shear keys; (3) Use pachometer to locate (E) outermost wall reinforcement; (4) Lay out grid of dowel holes to be drilled; and (5) Drill holes. Since the depth of each drilled hole and each beveled key is measured relative to the adjacent concrete wall surface after roughening, our retrofit crew typically holds off on drilling until after the entire contact surface has been bush-hammered and all keyways have been chipped to their required depth.  During our initial roughening and shear key chipping operations (e.g. steps 1 and 2), the outside face of some outermost layer wall reinforcement was inadvertently exposed.  This occurred either due to the bars being placed too close to the face of wall (e.g. insufficient concrete cover) in the original construction, or because the (E) rebar locations coincided with new key locations and were exposed when the keys were chipped.  Our field crew even tried to use our company-owned, old-school pachometer (basically a glorified stud finder--married up with a land line telephone receiver--used to locate (E) reinforcing steel, noted above in step 3), but this turned out to be inconclusive. The idea, of course, is to calibrate the instrument, locate the (E) bars, and then plot their approximate location on a reasonably smooth concrete surface.  We have had great success with this old instrument over the years, but in this case the concrete wall surface was too rough for us to determine rebar locations.  We tried to do the pachometer work before scabbling the wall surface, but the readings were erratic, and any layout marks would get wiped out during the roughening process anyway. Pachometer: reprint from ACI 224.1R-11. By the time our field crew finally began drilling the holes (step 5), they ended up hitting (E) reinforcing steel at every turn; with drill bit refusal occurring at various depths with no apparent rhyme or reason. What we ended up with is shown in the photograph below...a panoramic "Swiss cheese" mural of abandoned drilled holes (ADH). Abandoned drilled holes (ADH) and shear keys at retrofit concrete wall. After just a few hours of drilling, it dawned on us that the Swiss cheese scenario was going to be the rule--rather than the exception. On one hand, the City inspector was wondering how the field conditions might affect the specified "pull test" protocols established by the LDP.  (The specifications called for the Owner's test agency to perform tension tests intended to proof load 10 percent of dowel production, each day.)  We, on the other hand, were concerned because our installation labor costs were already running way over budget, not to mention the number of drill bits we were burning through. At that point, we (including the City's full-time inspector) requested the LDP visit the jobsite for a job walk to observe the field conditions and provide guidance. After a brief meeting in the City onsite trailer, we convened at the wall to rinse out the issues.  As it turned out, the LDP didn't seem bothered at all by what we showed him (see photo, above).  In fact--just the opposite. "This wall has been here for at least 80 years without even a crack", the LDP told us, "and it's not going anywhere now... the current ACI Code says we can't use drill and epoxy anchors until the parent concrete is 21 days old... obviously that's not an issue here. The retrofit is being driven by City ordinance coincident with a change in tenancy, not because of any structural distress...this concrete is here to stay, just ask your workers who are running the drills and chipping guns...just keep drilling, and try to get the holes as close as possible to their design location. Fill in all of the abandoned drilled holes (ADH) with either the approved non-shrink grout (drypack) or the approved epoxy adhesive...your choice...I will let you know if any pull test protocols need to be adjusted". (N.B.:  According to ACI 318-19-- Building Code Requirements for Structural Concrete--section 17.2.2 tells the LDP that "Adhesive anchors shall be installed in concrete having a minimum age of 21 days at time of anchor installation".) Since the large number of ADH don't seem to be of structural concern, that still leaves the issue of the cost impacts, which we did not bring up during the job walk. At bid time, we estimated the number of holes required and multiplied that by our standard unit rate per each; a unit price we developed over the years and which does not consider ADH or cost of drypack or epoxy ADH infills. Neither we (nor the City inspector) have seen such a large number of ADH. We did not qualify our bid to say that we assumed a certain number of ADH and expect to be paid for anything beyond that. So far, we have kept a log of all time and materials expended so far, numbers which are recorded with City inspector oversight. How would you recommend we approach the City Council for an equitable reimbursement of our extra costs? Answer:  There are several interesting nuances at play here.  Let's drill down just a little bit and learn what was driving the LDP's assessment. First: We know from the prebid meeting that the design team made a good-faith effort to determine what the (E) reinforcement should have been, based on the 1940's-era construction documents. Unfortunately, such documents could not be located. A complicating factor is that the building was most likely built during--or just after--World War II.  It is fair to say reinforced concrete construction at that time was highly dependent on what materials and labor force was readily available. The design may have called for unavailable bar sizes, and the equivalent area of reinforcement in smaller sizes was substituted instead. In other words, since they couldn't get the correct size bars, they used smaller bars--just a lot more of them.  Short of demolishing the wall, there is no easy way to know what happened when the structure was being built. Second: The LDP is obviously experienced with ADH, since he was able to review the work in the field and give guidance straightaway. At first glance, one might react the way you and the City inspector did, thinking this amount of ADH has got to be a structural problem.  Here at the ASCC Hotline, we run into examples like this quite often where photographs indicate conditions that might initially appear unsavory, but upon further review it turns out that there really isn't a problem at all.  So how did the LDP arrive at such a quick decision? As is typical with the design and construction of reinforced concrete structures, almost everything engineers and concrete contractors do is based on testing, experience, and a healthy dose of engineering judgement.  As it turns out, there have been several reports published that describe testing to determine the effects of abandoned drilled holes (ADH) on the load-carrying capacity of the survivors.  In addition, some material suppliers have conducted/sponsored test programs on their own to understand how their products will perform under various ADH boundary conditions in the field. We reviewed two such reports that appear in refereed engineering journals, and additional reports that were found in the adhesive (or anchor) manufacturer's web page technical sections.  In a nutshell, the following general statements can be made about the load capacity of ADH: Typical drill bit refusal occurs at depths between 3/4 inch and 2 inches, which coincides with nominal concrete cover to reinforcing steel. As long as the ADH are backfilled with the appropriate drypack grout or adhesive material, the concrete will heal and never know what happened. In some cases, the load capacity might even be enhanced by backfilling. In general, if an ADH is 3 or more anchor diameters away from the successful hole, there is no effect on anchor capacity, even if the ADH is not backfilled. On the other hand, if the ADH is within 2 diameters of the successful hole and is not backfilled, the load capacity will be reduced. The key takeaway here is to study the MPII (manufacturer's printed installation instructions), which will likely contain guidance on ADH relative to the product. That information should then be worked with any drilled anchor details and specifications given by the LDP in your construction documents. Third:  In order to get paid for the extra time and materials in excess of what you estimated and priced at bid time, you will have to make the case that the (E) rebar locations could not fairly be determined, even after the work started. The only way, really, that rebar was located on your project was with a drill bit or a chipping gun. In other words, this is a case of unforeseen conditions. Since the City inspector concurs with your experiences, that should weigh heavily in your favor when your request for compensation is considered by the City Council.  Since you have already developed a good rapport with the various City stakeholders, the good faith efforts demonstrated by all collaborators should go a long way in helping to make your case. ___________________________________________________________________ Question: What do we do when tolerances for a work item do not appear in the construction documents?  If the tolerance value is not specifically stated, doesn't that automatically mean that the tolerance is zero? Answer: In order to answer this one, we can find guidance in two important specifications published by ACI, namely ACI 117-10 Specification for Tolerances for Concrete Construction and Materials, and ACI 301-20 Specifications for Concrete Construction.  In both cases, the body of the specification text does not specify certain default tolerances for some items.  When that happens, the specification writer must use the checklists--given at the back of both ACI documents--titled "Mandatory Requirements Checklist" before releasing the project out for bid. In both cases, the designer has to do his homework and supply certain tolerances in the construction documents if they are really that important and desired by the Owner. If the specification preparer does not follow through with this task, then there is no contractor tolerance requirement. This does not automatically mean that the tolerance is zero. We can also "check the other guy's playbook" and view this condition through the lens of our structural steel colleagues.  In this case, the playbook is the AISC (American Institute of Steel Construction) Code of Standard Practice for Steel Buildings and Bridges (2016), section 1.10 Tolerances, as follows below: ___________________________________________________________________ Question: We are working on a large, commercial "big box" project that features a building footprint of approximately 200,000 GSF (gross square feet).  At bid time, our estimators divided the footprint into six equal sized slab-on-grade pour placements as shown in the plan view, below. This plan is excerpted from the submittal we prepared intended to show construction joint locations only. Once approved, we intended to distribute the plan to all of the follow-on trades for their use in planning their scopes relative to ours.  Separate drawings were submitted that showed reinforcement placing and saw cut joint locations. We were surprised when the design team rejected our pour plan, claiming that our layout constitutes a so-called "checkerboard pattern", which we all know has been frowned on by ACI for many years now. We are looking to the ASCC Hotline to provide guidance.  Please advise. Answer:  The plan you submitted features placements with aspect ratios that are clearly not arranged in "checkerboard" fashion.  In fact, just the opposite.  Below is an excerpt from ACI 302.1R-15 Guide to Concrete Floor and Slab Construction which straightaway tells the story at first glance.  As you can see in Fig. 10.1.1.1b below, your plan is clearly a variation on the "long-strip" construction placing sequence configuration and nowhere close to looking like a checkerboard.  Getting the design team's decision reversed should be a fairly straightforward matter. ___________________________________________________________________ Question: We are one of three competitors in the hunt for a project that bids this coming fall. The project is a three-building apartment complex featuring reinforced concrete podium-type structural frames.  Each frame includes 2 levels of parking below grade, and wood "stick" apartment framing starting at each podium level.  We--and our competitors--have been providing budget estimates over the past year. All three of us have built for this private developer in the past, although not with the same GC (general contractor). This Owner likes to spread the work around. After each round of budgeting, we make it a point to call the GC a week or so later to ask how our number is looking. (Sometimes we can get a "whisper number", but in this case--no dice). The best we can get is the encouraging reveal disclosure that our price is "competitive". Throughout the budgeting process, the LDP has shown most (but not all) walls as cast in place, using the shotcrete method of placement. A fair amount of walls at the parking levels, however, are shown as CMU (concrete masonry units). From what we can tell from the CMU typical details and the span lengths shown on the floor plans, these CMU walls must be load bearing, which means they have to be installed by others--and grouted--before the supported slabs in our scope are placed. In fact, it may be entirely possible that we will not even be able to erect our scaffold shores until the block subcontractor has demobilized.  Based on successful past experience, we are confident we can shave time off the schedule and save the Owner money by requesting a substitution to get the CMU walls changed to shotcrete. We intend to include the substitution as a VE (value engineering) alternate at the end of our bid proposal letter. Customarily--and most likely contractually-- "Request for Substitution" (aka RFS) proposals must be crafted with a narrative that explains how the proposed substitution will benefit the Owner in terms of Quality, time, and dollars. At one of our recent weekly, in-house estimator's meetings with our project managers and our company ownership, we penciled out the possible cost and schedule scenarios if the CMU walls were changed to concrete and added to our scope. How many shoot days would we now need? How much backforming would we have to pick up? How much rebar would have to be installed, and at what scheduled time frame?  And then the kicker: when we submit our formal substitution request, what quality of surface finish will we advertise? What "or equal" tolerances should we say we will follow for the substituted shotcrete walls? At this stage of the game, the construction documents are silent regarding tolerances for the shotcrete walls that are already shown on the drawings, let alone for any work added after the fact. In addition (and sorry to say), none of our own team members working on the estimate even considered shotcrete tolerances during the budgeting process as well. What tolerances should we follow for the shotcrete work already shown in the construction documents, and what tolerances should we propose to build to if the CMU-to-shotcrete RFS is accepted?  Please advise. Answer: In order to rinse this one out, we need to review certain ACI document requirements that apply to shotcrete tolerances--in step-by-step fashion--as follows below: ACI 117-10 section 1.1.2 tells designers and contractors that the document scope does not include tolerances for shotcrete. ACI 301-20 section 1.1.5 tells the contractor "Use shotcrete as designated in Contract Documents". ACI 301-20 Mandatory Requirements Checklist item 1.1.5 tells the specifier to "Designate portions of Work to be constructed of shotcrete. Concrete sections not initially designated as shotcrete may be subsequently considered for shotcrete placement after Contractor submittal for consideration. Refer to ACI 506R for guidance on shotcrete. Review ACI 506.2 and ACI 318 and specify requirements for shotcrete..." ACI 506.2-13 Specification for Shotcrete section 3.8.1 tells designers and contractors "Dimensional tolerances of shotcrete shall comply with Contract Documents". ACI 506.2-13 Mandatory Requirements Checklist item 3.8.1 tells the specifier "Specify tolerances based on function and appearance. Shotcrete can be built to the same tolerances as cast-in-place concrete; however, for some structures such as tunnels, only cover thickness is required and tolerances are not specified unless project-specific requirements dictate.  Sometimes shotcrete tolerances are increased by a factor of 2 from those in ACI 117..." ACI 506R-16 Guide to Shotcrete section 3.8 Tolerances: tells the reader "...shotcrete structures can be built to the same degree of accuracy and tolerance as cast-in-place concrete". Considering the above in its entirety, we can say the following: The LDP is obviously familiar with and comfortable with the shotcrete method of concrete placement. This will be helpful when it comes time for the LDP to review nozzleman's qualification cores and the actual contract work. The ACI 301 and ACI 506-series documents were written with the above in mind. Based on Mandatory Requirement checklist item 3.8.1 that appears in ACI 506.2-13, the LDP is obligated to approach each project in common sense fashion.  In other words, the LDP has to sit down, think about the upcoming project at hand, and then create the construction documents--including appropriate tolerances--to suit. Since you are still working with in-progress budget documents--roughly Level 4, or 75 percent complete (see ASCC VOICE Guidance column #3, Jan. 2022, for more on estimate levels), it is not surprising that the LDP has not yet specified the tolerances appropriate for the project.  On the previous project that you shot with this LDP, what tolerances were specified?  Did the question even come up?  We suggest you review the architectural documents to determine if any of the concrete walls are likely to be designated "architectural concrete".  For the CMU walls, check the finish schedule to see if any of those will be covered with a follow-on "architectural" finish.  This will give you an idea of the likely backform tolerances you will need to meet in order to satisfy Owner Quality expectations if the switch is made from CMU to shotcrete. Take a look at the other guy's playbook.  In this case, said playbook includes the Division 4 Masonry specification sections. If the CMU is changed to concrete, is there anything hiding in the Div. 4 playbook that you will inherit? ACI 301-20 Mandatory Requirement checklist item 1.1.5 recognizes that the concrete contractor might propose to build the work using the shotcrete placement method. If the VE change is accepted, some jurisdictions (e.g. public works projects) might require a formal revision to the specifications and the design drawings to incorporate the change from CMU to shotcrete. In that case, you are likely to have to cover the cost of the "redesign". It sounds like on this project, such engineering fee "backcharge" may be waived.  At least be aware of this potential cost associated with material change when you are estimating your VE cost items.  Depending on the way the Owner's test agency contract is crafted, there may be "extra" testing and inspection costs associated with the substitution from CMU to concrete.  Example: the inspection and testing required for the shotcrete nozzleman's qualification and so on versus the cost of inspecting and testing masonry prisms, etc. (N.B.: On some projects (not this one), reinforced concrete walls indicated as "form-and-pour" may be changed to shotcrete at contractor request. LDP "redesign" costs would not be appropriate in this case, since there is no revised structural design, only a change in the means and methods of forming and placement). _____________________________________________________________ Ray Hefner Tue, 29 Oct 2024 16:03:00 GMT f1397696-738c-4295-afcd-943feb885714:475 https://ascconline.org/Home/News/articleType/ArticleView/articleId/479/A-Message-from-the-Board#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=479 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=479&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/479/A-Message-from-the-Board A Message from the Board Bill Bramschreiber, Immediate Past President ASCC’s 2024 Annual Conference was Terrific! ASCC’s Annual Conference is held each September and is always a fun few days of networking opportunities, professional development, and access to learning resources for around 300 concrete professionals.  This year’s ASCC Annual Conference was held in Kansas City, Missouri. You have many choices of events that you can attend, and ASCC’s Annual Conference has never disappointed me.  Highlights for me this year were: ASCC’s highest honor is the ASCC Lifetime Achievement Award.  At the opening dinner Mike Schneider, who recently retired (sort of) from Baker Concrete became just the 14th recipient of this award.  Mike had over a 45-year career with Baker and retired as their Chief People Officer.  Mike is incredibly active in numerous concrete and construction service organizations, including serving as both ACI and ASCC president.  Mike strongly believes that it is to every concrete professional’s benefit to share their safety expertise with each other.  Mike has been a legendary advocate for improving safety in the construction industry; including on mental health mindfulness, transitioning to helmets to reduce traumatic brain injury, opiate overdose awareness and pain management, and suicide awareness and prevention. Keynote speaker Donnie Campbell was a math teacher and the high school basketball coach for Jason Sudeikis. Jason credits Donnie as being the major inspiration for his character Ted Lasso for the hit TV series.  Donnie gave folksy anecdotes and lessons on how to make an impact by using positive leadership to develop people first through building character and trust.  To inspire each of us to discover our “MVP”; your Mission, Values, and Principles, to inspire individuals to reach their potential and teams to reach new heights. The next day’s keynote speaker was former Team Chaplain and Character Coach for the Kansas City Chiefs Phillip Kelley.  Phillip described how his strengths have only been able to come through due to his own weaknesses and failures, including a battle with addiction.  Using his acronym for culture, COALture, Phillip detailed his four keys to leveraging authenticity for explosive growth (both personally and professionally); Clarity, Ownership, Attitude, Leadership development. ASCC First Vice President Cory Lee from Martin Concrete Construction led a panel discussion on Addressing Type 1L Cement from a Business Perspective – How to Manage Your Risk.  Many at ASCC and throughout the concrete industry are working to address the various technical issues being seen in dissimilar ways in different parts of the country with Type 1L Cement.  Cory has a passion about also getting the word out on how concrete contractors can better minimize their risk from a business standpoint.  Lawyer Chris Dunn with Winstead provided construction law precedents, went through dangerous provisions commonly found in subcontracts, and discussed a three-layered defense to protect a concrete contractor during bidding, contract negotiations, and proactive communication and self-protection.  Mark McGraw with Sandler Training advised on choosing the best time, place, and how to have difficult discussions about Type 1L.  Hint; “The best way to deal with a bomb is to defuse it before it goes off.”  Handouts for both Chris’s and Mark’s presentations are available. ASCC SRMC (Safety and Risk Management Committee) Director Mark Messing from Joseph J. Albanese and Barry Nelson with FactorLab presented on how AI is becoming a powerful disruptive force for construction safety.  How apps such as SmartTagIt can be used as a platform to gather tens of thousands of data points from videos of safety meetings such as pre-task planning conversations.  Using natural language processing (NLP) technology; analytics can then be derived, calculated automatically, and summarized to allow teams to share this knowledge.  This accelerates training and mentorship, resulting in a measurable and significant improvement in pre-task planning leadership and better team conversations.  Many safety statistics are lagging indicators such as an OSHA Incident Rate, data such as this gives a leading indicator to allow for improvement to possibly prevent incidents. ASCC always organizes golf and other fun activities for the closing Friday afternoon of each conference.  This year there were tours of the National World War 1 Museum, the College Basketball Experience and the Nelson-Atkins Museum of Art available. The ASCC Annual Conference is always a great way to learn and network.  Next year we will be in Indianapolis, please join us. Ray Hefner Tue, 29 Oct 2024 08:20:00 GMT f1397696-738c-4295-afcd-943feb885714:479 https://ascconline.org/Home/News/articleType/ArticleView/articleId/478/Updates-from-the-CPC#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=478 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=478&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/478/Updates-from-the-CPC Updates from the CPC  Ryan Klacking, Council Director Greetings, CPC Members!  As the vibrant colors of fall start to emerge, we are excited to bring you the October edition of the CPC newsletter. This month, we have a range of updates, events, and resources designed to keep you informed and inspired in the concrete polishing industry.  Industry Insights  1. Concrete Polishing Trends for 2024  Stay ahead of the curve with our in-depth analysis of the latest trends. From sustainability practices to advanced polishing technologies, our experts share what’s expected to shape the industry in the upcoming year.  2. Safety Focus: Dust Control in Polishing Operations  Ensuring the health and safety of your crew is paramount. This month, we’re spotlighting best practices for dust control during polishing. Learn about the latest OSHA guidelines and innovations in dust collection systems that can enhance the safety and efficiency of your operations.  Resources & Technical Updates  New Polishing Guidelines: CPC has released updated guidelines for polishing high-traffic commercial floors. Members can access these through the CPC online portal. Make sure your projects meet the highest standards with the latest industry-approved techniques.  CPC Knowledge Hub: Looking for technical articles, case studies, or how-to guides? Visit the CPC Knowledge Hub for an extensive collection of resources tailored for concrete professionals.  Get Involved!  CPC is dedicated to advancing the concrete polishing industry through collaboration and education. Here’s how you can get more involved: Join a Technical Committee; We are seeking members for our Standards and Technical Committee. Help shape the future of the industry by contributing your expertise.  Concrete Polishing Council CPC  The CPC serves as an educational resource for contractors and others in the design and construction industry through certification, education, technical documents, and awards  Decorative Concrete Council DCC  The DCC educates contractors on the technical and business aspects of decorative concrete contracting and promotes decorative concrete to designers, owners, and end users through demonstrations and seminars at the Annual Conference and World of Concrete, the DCC Annual Awards competition, and community projects and outreach. Manufacturers’ Advisory Council MAC  The board of this associate member Council advises the ASCC on how the organization can provide the best value to its vendor members. The MAC has a strong voice in all sponsorship decisions that directly affect these valued companies.  Safety & Risk Management Council SRMC  This Council educates and provides materials to contractors on all aspects of safety and risk management relating to concrete contracting and insurance. The Council also provides oversight on publications, demonstrations, and everywhere we display safe practices.  Thank you for being a part of the CPC community. Together, we continue to elevate the standards and practices within our industry.  Wishing you a productive and safe October!  Ray Hefner Mon, 28 Oct 2024 08:01:00 GMT f1397696-738c-4295-afcd-943feb885714:478 https://ascconline.org/Home/News/articleType/ArticleView/articleId/474/How-Can-Technology-Change-the-Way-You-Work#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=474 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=474&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/474/How-Can-Technology-Change-the-Way-You-Work How Can Technology Change the Way You Work? Mike Hernandez, ASCC Technical Director There are various new and developing technologies on the market that are of use to concrete contractors. ASCC technical staff and Associate Members can assist you with many of them. Members can also ask for feedback from the general membership in the ASCC Forum. Total StationThe most accessible technology may be to invest in a Total Station for self-performed layout or verification of layout by others. They vary in cost from $3500 to over $40,000 for a robotic machine capable of long-distance land survey. There are 5 arc seconds, 3-second and 1-second instruments on the market. If you are constructing a medium-sized commercial building or smaller, a 5-second Total station is probably just fine. Personally, I prefer the 2-man team with an instrument man and a rodman. They often act as a journeyman and apprentice team. The rodman is staking points and can someday be an instrument man himself. Also, a robotic total station was stolen in a grab-and-run operation too close to a busy Miami street years ago. Fortunately, the surveyor had written his name and our company name under the batteries with ultraviolet ink so he was able to identify it at a pawn shop several weeks later with a UV flashlight, despite the serial numbers being scratched off. You will also need software, a data collector, and training. I feel the expense is well worth the upgrade in quality vs traditional processes.   Laser Scanner In the upcoming September issue of ACI’s Concrete International there is an article by ASCC Member Leo Zhang with The Conco Companies regarding laser scanners. The article compares the performance of several competing scanners and provides guidance on their speed and accuracy at various distances. Absent from the article is the cost. The ones tested range in price from ~$23,000 to $104,000 plus the cost of the software and training. Scanners are helpful in capturing existing conditions or performing as-builts. Having used scanners on projects for 17+ years and as a member of ACI 117 laser scanning subcommittee, they are a double-edged sword. They will find mistakes you did not realize were there which could be used against you or help you mitigate a dispute with minimal grinding, patching and rescanning. Our team performed multiple rounds of grinding-patching-scanning of vertical shear walls to minimize the impact of a stucco sub wanting $100,000 to thicken the coatings on several 5-story shear walls back in 2007 with similar mitigation processes more recently. Flatwork slab topographs or “heat maps” are the most common work product. It will find the high, intermediate, and low points in a slab. Be careful that the contour line spacing is reasonable if someone else performs the scans. Scans of elevated decks prior to--then after--shoring removal have made several disputes go away over the years because concrete contractors can’t control deflection, only the top surface (prior to shoring removal) is in their control. Building Information Modeling (BIM) If you are constructing a moderately complex structure or if the drawings seem incomplete, then consider using BIM to model the concrete frame for the project. The structure is constructed digitally before going to the field. The Mechanical-Electrical-Fire Protection-Plumbing trades are modeling their work regularly to cram their scopes into walls and ceilings using clash detection and coordination so this might be happening with the general contractor already. Some aspects of the final concrete are often not coordinated properly in the "For Construction" set of plans or additional information is added during shop drawing review. The goal of the BIM modeling is to provide the field with a coordinated set of line drawings checked against architectural drawings, structural drawings, civils and includes blockouts and embeds. A single source of truth. This exercise should decrease risk, improve efficiency and thus reduce cost. From this you can provide model based layout to a total station, run schedule simulations (4D) or even use it to model the formwork and rebar. BIM can even be used with a virtual reality headset to digitally walk through the structure. The investment is substantial, so consider using a domestic or international 3rd party consultant until you are familiar with the processes enough to know which software to buy and have an enthusiastic modeler on staff. Part of the issue with evaluating your return on investment is it will be impossible to accurately quantify actual $avings of a well-coordinated set of drawings vs finding issues during concrete construction operations or worse, by a follow-on trade. I like to say “It is hard to place a value on the bus you did not get hit by.” When a project goes smoothly, and the team meets the schedule and quality goals then moves to another project without rework that is a good project.    Drones The use case for drones is for progress photos and capturing post-tensioning and rebar prior to concrete placement. As an FAA Licensed part 107 drone pilot, I have flown dozens of flights to capture progress photos. Having those progress photos was helpful in updating the master schedule and billing percent complete. Other projects have used a drone flying a programmed route like mowing a lawn to capture rebar, post-tensioning and conduits prior to placing concrete. The series of images can be combined for a high-resolution as-built composite image if a slab ever needs to be drilled.  If you are going to use a drone on a commercial job site, go through the proper licensing and liability insurance procedures. Artificial Intelligence (AI) There are several AI tools available if you want to push the innovation envelope. One is a scheduling tool that will run thousands of schedule “what if” scenarios based on the sequence logic, durations, manpower, and equipment constraints you input. It will generate the fastest solution to complete the project. The more complex the schedule, say 2500+ activities, the more likely it is to come up with a novel solution. A former employer was using this tool 6 years ago and we tested our plan against it. Having managed projects with a best-case scenario master schedule it is a high-risk and high-reward setting. A few hiccups in manpower or formwork cycling and the ultra-fast plan are out the window with craft labor and general conditions consuming the perceived savings. Massive overtime and a difficult conversation with your client come next. The lesson learned was to under-commit and over-deliver as much as possible. Try this tool when the whole project team can get on board with your innovative AI plan to share the risk. If you would like additional details about AI leveraged project scheduling, please contact me. A less risky use of AI is for language translation. With a predominantly Hispanic workforce in many companies, the more we can provide our workforce content in their native language, the more likely we are for them to internalize the text. AI can translate to hundreds of languages. I am still trying to determine if Google Translate or Chat GPT does a better job with concrete construction lingo. Your feedback is welcomed.      As contractors we have to make buy-sell-lease decisions for the benefit of the long-term health of the organization. Fellow ASCC members and staff can help you recognize the pros and cons of technology investments. Take advantage of these resources as a benefit of ASCC membership. Ray Hefner Fri, 30 Aug 2024 16:03:00 GMT f1397696-738c-4295-afcd-943feb885714:474 https://ascconline.org/Home/News/articleType/ArticleView/articleId/473/Stay-Safe-In-the-Dog-Days-of-Summer#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=473 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=473&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/473/Stay-Safe-In-the-Dog-Days-of-Summer Stay Safe in the Dog Days of Summer, Rich Cofoid, DCC Council Director This month I’ve been thinking about a subject that not only affects decorative contractors but all concrete contractors and that is summertime temperatures. Living in Florida in July and August you can’t help but think about it every time you step outside, day or night. Our concrete construction business requires working outside most of the time. As global warming continues to increase this is a situation that isn’t going away and may only get worse, no matter where you live. Every year tens of thousands of workers suffer from heat-related illnesses and unfortunately, dozens die. Worse yet, those numbers are increasing annually. Accordingly, we must all take steps to ensure we have a plan, are prepared daily, educate our workers (both to the hazards and resources available), and monitor our working conditions and employees. Like all workplace safety, OSHA has guidelines and regulations to help employers protect their workers from heat-borne illnesses. Believe it or not, only 5 states (CA, CO, OR, MN, and WA) have state regulations in place, but many more are looking to introduce bills addressing this issue. The NIHHIS (National Integrated Heat Health Information System) has additional information that can be found at HEAT.GOV. They also promote an annual heat safety awareness week that typically occurs around May 1 as we transition from Spring to Summer. Before I list a few safety measures, let's discuss the different levels of heat illnesses in order of severity: Heat Cramps: Painful muscle spasms that usually occur during heavy physical activity in hot environments. They are often an early sign that the body is having trouble with the heat. Heat Exhaustion: This occurs when the body loses excessive amounts of water and salt through sweating, leading to dehydration. Symptoms include heavy sweating, weakness, dizziness, nausea, headache, and fainting. Heat Stroke: The most severe form of heat-related illness, heat stroke occurs when the body’s temperature regulation fails, and the body temperature rises to critical levels (usually above 104°F or 40°C). Heat stroke is a medical emergency and can be fatal if not treated promptly. Symptoms include confusion, loss of consciousness, seizures, and hot, dry skin. Here are a few safety measures you can take: Provide Training: Ensure that employees are trained to recognize the signs and symptoms of heat-related illnesses and know what to do if they or their coworkers show signs of distress. Schedule Outdoor Work Carefully: Whenever possible, schedule outdoor work during the coolest parts of the day, such as early morning or late evening. If work must be done during the hottest part of the day, ensure proper monitoring procedures are taken.  Our members in the SW US can attest to the fact that many pours are done before the sun comes up. Provide Adequate Water and Rest Breaks: Encourage employees to drink plenty of water throughout the day, even if they do not feel thirsty. Provide access to shaded or air-conditioned rest areas where employees can cool off during breaks. Monitor Weather Conditions: Stay informed about weather forecasts and be prepared to adjust work schedules or take additional precautions as needed during periods of extreme heat. Encourage the Use of Protective Clothing and Equipment: Provide lightweight, loose-fitting clothing and encourage employees to wear hats and sunglasses to protect against the sun’s rays. Provide personal protective equipment (PPE) that is designed to keep workers cool while providing adequate protection. ASCC has a Safety Bulletin that addresses this topic as well. In the coming days and weeks, stay safe out there! Ray Hefner Fri, 30 Aug 2024 15:40:00 GMT f1397696-738c-4295-afcd-943feb885714:473 https://ascconline.org/Home/News/articleType/ArticleView/articleId/472/Guidance-for-Concrete-Contractors31-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=472 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=472&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/472/Guidance-for-Concrete-Contractors31-in-a-Series Question: We are building a shopping mall complex that consists of a large "anchor tenant" store, 3 adjacent "strip mall" type storefronts, and a free-standing convenience store at the end of the property. Our base contract scope of work includes all reinforced concrete foundations, slabs on grade, stub walls, and miscellaneous concrete curbs and mechanical pads that are shown within each building footprint. All follow-on concrete parking lot and landscape work is by others. The Owner recently issued a VE (value engineering) Bulletin that deleted the free-standing convenience store portion of our contract scope.  We prepared a detailed cost estimate and submitted that to the Owner in a deductive change order proposal. The Owner rejected our proposal because we did not credit back any of the overhead and profit associated with the deleted portion of the work. (Our base bid was a rip-and-read lump sum. We did not break out the individual costs of each structure in our number; either on the bid form or even in our in-house estimate spreadsheets). We are second-generation concrete contractors and have never credited back overhead and profit for any deductive changes on any of our past projects. At a recent job site meeting with the architect, we were told the Owner is disappointed because he thought this whole VE exercise was going to result in some huge financial windfall. Is the Owner correct in demanding we credit back our overhead and profit? Answer:  It depends.  If your project construction documents contain AIA (American Institute of Architects) document AIA 201-17 General Conditions of the Contract for Construction, then that is where the ground rules for additive and deductive change orders are likely to be found. We note here that the protocols for pricing deductive changes could have appeared in any number of places prior to bid time, e.g. in an Instruction to Bidders, in Supplemental Conditions, in the Division 1 front-end specifications, and so on. The key now is to find out where such protocols are written in the actual contract that you signed.  In other words, contract changes, modifications, carve-outs and so on often are slipped into the final contract prepared by the Owner between bid time and the day you sign on the dotted line. As an example, examine a copy of your signed contract.  If it contains AIA 201-17, refer to Article 7 titled "Changes in the Work".  Once you have found Article 7, look for section 7.3.8., which typically covers deductive changes to the work scope.  More on this below. This exact topic was explored when the ASCC Technical Division was preparing Position Statement #45 "Managing Concrete Projects: Concrete/Steel Price and Delivery Volatility Risks"--which became necessary after ASCC members reported problems getting fairly compensated for costs incurred associated with the COVID-19 pandemic, supply chain disruptions, and other problems that the concrete contractor cannot possibly control. What we found was consistent with your experience over the years with deductive change orders and was stated as follows in Position Statement #45: "In accordance with AIA Document 201-17, § 7.3.8, it is customary for deductive changes to be the actual net cost, not including overhead and profit". This was based on AIA 201-17 section 7.3.8, which appears in unaltered (e.g. template default aka "customary") form as follows below: We all should remember that when preparing the front-end construction contract documents, the Owner starts out with a set of base document templates and is then free to make any modifications, additions, carve-outs and so on from there. This is true not only with contract General Conditions, but with the AIA Masterspec templates for the project specifications as well. In theory, all construction front-end documents should be custom-tailored to each project. Closer to home, the concrete industry specifications that typically apply to our work on a routine basis (e.g. ACI 117-10 Specification for Tolerances for Concrete Construction and Materials and ACI 301-20 Specifications for Concrete Construction, for example) contain Mandatory and Optional Requirement Checklists at the back end of each document so the specification writers can tailor these documents to suit each project on a custom, case-by-case basis.  Here's one example of risk transfer we found from another project where the Owner modified the default AIA 201-17 § 7.3.8 such that the concrete contractor was in fact obligated to rebate the overhead and profit dollars in deductive change order proposal credit amounts: (N.B.: When considering the "actual net cost only" price rebate clause, we should recognize several key items, including any contractor lost opportunity costs and the timing of the Bulletin itself e.g. was the change issued a week after contract award...or was it issued a week before work on the deducted scope was supposed to start?  What costs were incurred reviewing and pricing the deduct? Have any concrete trial batch costs been incurred before the Bulletin was issued? Have any long-lead items been ordered? Have any shop drawings been prepared? After all, "overhead" is simply shorthand for "the cost of doing business", some costs of which were likely incurred by the time the Bulletin was issued on your project.  So--instead of reaping a windfall--the Owner may just discover that deleting the work turns out to be more expensive than keeping it in.) The key takeaway here is that the concrete contractor's legal counsel should perform thorough pre-bid and post-bid, line-by-line reviews of all front-end construction contract documents to flush out any clause modifications or carve-out booby traps that might have been slipped in to transfer risk to the contractor.  By the same token, the contractor's pre-bid estimating team should be reviewing every line in the Division 3 specifications, as well as those in the playbooks of all adjacent follow-on trades.  You might even try and contact some of the other subcontractors on the project to see how they handled their deductive change proposals as well. Insider's note: The AGC (Associated General Contractors of America) has published quite a comprehensive review and commentary on AIA 201-17 that explores several modifications, carve-outs, and risk-shifting booby traps that the AGC recommends be reviewed before contractors bid on projects that contain AIA 201-17. A link to the AGC document (there is no charge) titled "AGC's Commentary on the AIA A201 General terms and Conditions Document, 2017" is here: AGC Commentary on the AIA 201 General Terms and Conditions Document ___________________________________________________________________ Question: We are working on a project that features elevator core shear walls that are infested with large reinforcing steel bars--#11 and #18 bar sizes are the typical vertical bar marks. There are embedded steel weld plates located near the top of the walls intended to carry the future follow-on structural steel and metal deck floor system.  In many cases, our field crew is having to bend the embed plate shear studs out of the way of the reinforcing steel bars in order to get the wall gang forms set in their proper location. The project inspector is saying that the bent embed studs constitute a structural problem and is making us replace any embed plates that feature bent studs. As a result, we are getting backcharged by the embed fabricator for detailer overtime, fabrication shop overtime and trucking overtime costs incurred to get the replacement plates delivered to the job site in time for us to make our scheduled concrete placements.  Our crews are then having to work overtime to replace the plates and get the wall panels set into place. It is not feasible for us to coordinate the work and install the reinforcing steel curtains in such a way as to outsmart the conflict between the studs and the steel bars. We cannot tie the plates into place on the outside wall face rebar curtains before setting the wall forms due to the large size of the plates--the plates must be bolted to the wall form panels. Is the inspector correct? Are the bent embed shear studs really a structural problem? We have searched our ACI reference library and cannot find any words of encouragement therein. Please advise. Answer: It depends. To solve this one, we need to have a look in the other guy's playbook for guidance.  In this case, we are talking about documents published by AISC (American Institute of Steel Construction) and AWS (American Welding Society).  As we will see, the bending of steel shear studs fastened to the parent steel plates (or beam top flanges) via welding is simply a matter of degrees. (N.B.: Part of the answer can be found by watching the metal deck crew install their work and then watching the inspector who follows right behind them. The next time you are on a SOMD (slab on metal deck) job, try to get up on the deck when the metal decking sheets are being attached to the top flanges of the structural steel floor beams with a weld gun. After the studs are shot through the decking onto the parent base metal (e.g. the top steel beam flanges), watch what the inspector does next). According to AWS D1.1/D1.1M:2020 Structural Welding Code-Steel, the inspector first performs a visual inspection to confirm there has been a successful 360-degreee weld flash (fillet). Then, according to section 9.8.1 Visual Inspection, "if a visual inspection reveals any stud that does not show a full 360-degree flash or any stud that has been repaired by welding, such stud shall be bent to an angle of approximately 15 degrees from its original axis".  If you watch the inspectors evaluating the shear stud installation in sections of newly installed sheets of metal decking, you will likely see them using a 2-lb. hammer as their inspection instrument of choice to augment the visual inspection. The so-called "ring test" involves smacking the stud with the hammer and listening to make sure the result is the sweet sound of ringing steel. If the stud fails the ring test, then the hammer is typically then used to bend the stud to the required 15-degree angle as described above (sometimes the inspector bends the stud with a length of pipe). AWS D1.1 section 9.8.3 Bent Stud Acceptance Criteria then tells us "The bent shear connectors...to be embedded in concrete...that show no signs of failure shall be acceptable for use and left in the bent position." So--for shear studs--the magic number for acceptance without engineering review appears to be bends up to 15 degrees from the original axis.  If your field crew is bending the studs more than 15 degrees, all may not be lost, since AWS D1.1 section 9.6.7.1 Bend Test describes prequalification testing whereby studs are bent between 30 to 90 degrees from their original axis in the shop.  Your LDP should review this and advise if any studs bent more than 15 degrees constitute a structural problem. If the LDP determines the bent studs are a problem, it may be possible for additional studs to be welded to the embed plates to supplement the studs that were bent instead of trashing the entire embed plate assembly. In similar fashion, the AISC Design Guide 23 Constructability of Structural Steel Buildings indicates that mislocated steel anchor rods can be field-bent to an offset of up to 15 degrees to correct "slight mislocations" as indicated below in Fig. 7-6: ___________________________________________________________________ Question: We are trying to find a past ASCC VOICE column that discussed reinforcing steel at elevated temperatures.  We found a recent VOICE article (Guidance #27, March 2024) that featured launch pad concrete, refractory concrete, and exploding concrete, but that's not the one we need.  We are looking for the one that talked about the effectiveness of concrete cover. Please advise. Answer: You are referring to an ASCC Hotline social media post about 16 months ago regarding fire testing and concrete cover. The source of that post was an excerpt from the ASTM Blue Bible, Chapter 25. To oversimplify enormously, if we subject a concrete wall placed with normal weight concrete (NWC), for example, to an ASTM standard fire test (ASTM E119-20, Standard Test Methods for Fire Tests of Building Construction and Materials), then--after 1 hour--the rebar with 1 inch of concrete cover on the applied heat side will reach a temperature of 800 degrees F.  The rebar with 2 inches of concrete cover will reach a temperature of 400 degrees F.  The rebar with 3 inches of cover--after 1 hour--will be hardly warm to the touch. Since we are on the subject of hot rebar, ASCC Hotline callers know from our close study of ACI 301-20 Specifications for Concrete Construction that section 5.3.2.1(c) tells us "If temperature of reinforcement, embedments, or forms is greater than 120 degrees F, use a fine mist of water to moisten and cool hot surfaces.  Remove standing water before placing concrete". So the question then becomes "how hot would the ambient air temperature have to be in order for rebar bundles in direct sunlight to attain the temperature of 120 degrees F that causes the ACI 301 water misting to kick in? " It might be possible for us to back into that answer, based on a derailment risk assessment study performed in Wyoming for the railroad industry.  In that case, the "risk" part involved the possibility of the buckling of the steel railroad tracks boldly exposed to the sun.  What the researchers found was that an ambient temperature of 103 degrees F resulted in a maximum steel rail temperature of 133 degrees F--a bump of 30 degrees F above ambient.  So if the ambient temperature is 90 degrees F, would that then result in a rebar bundle reaching the ACI 301 maximum temperature of 120 degrees F before water misting is required?  ___ Ray Hefner Fri, 30 Aug 2024 14:56:00 GMT f1397696-738c-4295-afcd-943feb885714:472 https://ascconline.org/Home/News/articleType/ArticleView/articleId/471/Interior-Slab-Mixes-with-IL-Cement-Study-by-ASCC-ACI-302#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=471 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=471&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/471/Interior-Slab-Mixes-with-IL-Cement-Study-by-ASCC-ACI-302 Interior Slab Mixes with IL Cement Study by ASCC & ACI 302 Mike Hernandez, ASCC Technical Director Surveys collected in 2023 indicate many concrete contractors have had issues with interior slab mixes using ASTM C595 Type IL cement, while many others (~50%) report no new issues. ASCC Members requested through ASCC and ACI 302 committee meetings that there be a project to collect concrete mixes and cement mill certificates from across the country to attempt to discover what is fundamentally different between the mixes performing well vs those that are not. This investigation will be across all lower 48 states and 8 NRMCA regions. The analysis will be performed by an artificial intelligence, AI, platform and validated by industry experts. A report to follow with a list of regional strong and weak correlations of changes likely to help improve the mix and what is not likely to improve the mix performance. This is keeping in mind that an expert consultant will be better at looking at one specific mix combination than any macro analysis looking at trends in hundreds of mixes. This exercise is in addition to other industry wide or project specific low carbon concrete efforts. The request was sent to ~200 ASCC contractors and ACI 302 members requesting mixes. In addition to 2023 and 2024 mixes with IL cement the request was made for 2019 mixes with I/II (or II/V) cement concrete, to establish a baseline for the AI of state of the industry prior to the wide production of IL cement. If you would like to participate, please send submittals and batch ticket data to mixes@ascconline.org  Please send: Several interior, 3000 to 5000 psi, non-air entrained, normal weight concrete slab mixes from 2023-24, using IL cement. Any quantity would be helpful. The information needed is: • Mix Proportions – from submittal package and batch tickets • Cement Mill Certs - 2023-24 ASTM C595 • Aggregate Gradations - % retained on sieves • Admixture names - will give admixture Type • Strength data - from submittal package & actual • Batch ticket(s) to observe seasonal admixture adjustments • Feedback from the finishers if each IL mix performs as expected or has issues, via survey, sent after mixes submitted. Please send any questions to mhernandez@ascconline.org. Ray Hefner Mon, 15 Jul 2024 20:30:00 GMT f1397696-738c-4295-afcd-943feb885714:471 https://ascconline.org/Home/News/articleType/ArticleView/articleId/470/How-to-Use-CPC-Classes-and-Levels-to-Specify-Polished-Concrete#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=470 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=470&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/470/How-to-Use-CPC-Classes-and-Levels-to-Specify-Polished-Concrete How to Use CPC Classes and Levels to Specify Polished Concrete Ryan Klacking, CPC Council Director The Concrete Polishing Council (CPC) has been setting industry standards for many years now. Defining aggregate exposure and level of sheen in a systematic way has made positive changes and strides within the industry. Prior to this advancement, polished concrete was relayed in a format of steps, grits and the number of passes.  However, presenting a polished concrete flooring system by steps and grits left too many open opinions and potential cost changes that deviated from the required expectation. Owners, architects, and buyers of polished concrete had a difficult time obtaining what they expected or envisioned as well as being hit with cost changes that wasn’t understood. Because of the CPC, there are now three (3) defined classes for aggregate exposure and four (4) defined sheen levels of appearance for polished concrete. A selection of Floor Class and Floor Appearance has allowed owners, architects, and contractors to standardize the polished concrete floor system. These advancements have been proven to increase adoption, predictability, and reliability in specifying or choosing polished concrete as the preferred flooring system. The CPC has also included language in the Aggregate Exposure and Appearance charts for verifying and testing the flooring system to validate that the installation meets the specifications. Users of the Aggregate Exposure and Appearance chart will find a plethora of benefits. Firstly, when you specify the floor class and level, you’re specifying the overall aesthetic look of the floor you envision. For an owner, architect, designer or specifier this is the way to ensure your expectation is being met and you’re receiving proposals that align with the finished outcome. For a polishing contractor this is a benefit as you can master your recipe for achieving the floor class and level instead of focusing on following drafted means and methods that may or may not achieve the overall specified flooring system.  The CPC suggests that polished concrete flooring systems should be tested and judged by refinement which is measured prior to any penetrating, semi-penetrating or topical sealers. Testing polished concrete Distinction of Image(DOI), and haze level with a clarity meter ensures the owners are receiving a refined and durable floor that meets their expectations prior to any stain or gloss enhancing sealers. Many stain or gloss enhancing sealers can cover up scratches that were not removed due to improper floor processing as well as increase gloss or sheen levels. For this reason, the CPC recommends that the testing be completed prior to any sealer applications to ensure the floor has properly been refined. It’s exciting to announce that the CPC will be releasing a technical document with the recommended instructions of how to properly set the test locations, how many test locations and how to pass, fail or troubleshoot polished concrete floors by testing measurables.  Ray Hefner Mon, 15 Jul 2024 13:58:00 GMT f1397696-738c-4295-afcd-943feb885714:470 https://ascconline.org/Home/News/articleType/ArticleView/articleId/469/Guidance-for-Concrete-Contractors30-in-a-Series#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=469 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=469&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/469/Guidance-for-Concrete-Contractors30-in-a-Series Full disclosure: This column marks the 30th installment of the "Guidance for Concrete Contractors" educational series featured here in the pages of our ASCC VOICE monthly newsletter. What follows below is a modest retrospective, where we take a little stroll down memory lane--paved with concrete, of course--to see how the "Guidance" series has hopefully helped to keep us on time, under budget, and within ACI industry standard tolerances. If you really want to know the truth about it all, out of all the Hotline calls that inspired the past 29 episodes, many serve as reminders that concrete construction is one tough business indeed--a high-stakes obstacle course-- peppered with daily hurdles for ASCC members to clear, and booby traps to be avoided (and hopefully outsmarted) at every turn. Construction booby traps are typically known to go off at any time between bid day and final retention payment. In the worst cases, we might even blaze right past the scheduled contract end date and wind up yet another year later sitting in some attorney's office for deposition with our final payment amount hanging in the balance. Over the course of that "Guidance" 29-column run, we encountered all kinds of creative backcharge issues--some amusing, some even offbeat--ranging from misunderstanding of what constitutes ACI 117 class B formwork offset tolerances to the time allowable for rainwater in a birdbath to evaporate. We found out why certain slag concrete wall surfaces may appear greenish-blue when form panels are stripped. And, for ASCC concrete estimators, we suggested carve-out qualification language for contract bid proposals to help neutralize potential risk items--and protect your margins. We constantly encouraged "Guidance" readers to always try to have a look inside the other guy's playbook in order to defend ourselves from questionable backcharges. In doing that, we discovered why the concrete guy is not responsible for cleaning up shot-on shear stud ferrule debris prior to metal deck fill placements--and why it is the metal building contractor that owes the shims under the metal building wall stud sill tracks--and not the concrete contractor. And we learned that breaking out the project manual and spending just a few hours before bid time leafing through the odd-numbered project specifications (usually just between divisions 1 and 9 is all it takes) to see what scope the follow-on trades owe the project--a practice which can often prove to be a very wise--and profitable--time investment. And, of course, we had to get a grip on the unfortunate reality that some of these booby traps are self-inflicted--and totally avoidable. Sometimes, the problem is your basic, brand-X field error:  the crew put something in the wrong place in the heat of battle. At other times, it was disclosed during several Hotline calls that the crews installing the concrete work had never read their project's Division 3 specifications governing their scope; had never seen their own subcontract "Exhibit B"; and had never even been exposed to industry standards ACI 301 and ACI 117. These are among the most important documents that govern almost every project concrete scope. They must be carefully read--and fully understood-- especially by all onsite personnel immediately responsible for performing the work. There used to be a time when contractors were required to perform this simple task by keeping a collection of all relevant ACI reference documents within reach in the jobsite trailer, as you can see in section 1.3.3 below, excerpted from this 2005 version of ACI 301: Insider's note: Evidently, this jobsite reference document requirement has been scrubbed from the specification and does not appear in subsequent versions of ACI 301. As of today, however, this essential reference compilation itself has been updated, renamed, and reissued as publication "MNL-15(20) Field Reference Manual: ACI 301-20 Specifications for Concrete Construction With Selected ACI References". No matter what one's job title happens to be (e.g. Superintendent, Estimator, Inspector, Project Engineer, and so on) MNL-15(20) can prove to be one of the most valuable document investments an ASCC member can ever make over the course of one's entire career in concrete construction.) By and by, we explored potential strategies and methods (March 2021 VOICE article:  "Blindsided by COVID-19") to recover costs when ASCC contractors were blindsided by COVID-19.  Right behind COVID, the Hotline started receiving calls alerting us to another issue that was catching concrete contractors (and other stakeholders) by surprise: the  roll out of Type IL cement, aka "portland limestone cement or PLC". Since then, the controversies surrounding limestone cement have grown as use of PLC increases market share replacing I/II or II/V cement in more and more urban and rural construction markets. Although there were a few concrete engineering consultants located in our midwest and southern markets who had already been privately commissioned to investigate reported potential side effects of this new blended cement, we here at the Hotline didn't actually start fielding PLC Hotline calls placed by ASCC members until summer of 2022.  By that time, the World of Concrete producers were already well-aware of the PLC issues being reported in certain US markets. To stay abreast of these breaking industry developments, World of Concrete 360 (WOC360) organized two PLC-related seminars scheduled to be held at the Las Vegas event in January 2023. This Hotline Operator attended both of them.  The first of the WOC seminars we attended was presented to a large, completely packed room by former cement industry insider Tim Cost, P.E., FACI called "What You Need to Know About the New Type IL Portland-Limestone Cement".  We found the Cost presentation to be informative, straight-up and fair--coming from an experienced engineer and researcher who had spent many years himself employed by one of the major (e.g. worldwide conglomerate) cement industry players. Included in the Cost presentation were acknowledgements of reported PLC , side effects especially in several areas of vital importance to ASCC concrete finishers: bleeding, water demand, possible surface crusting, set time and obtaining acceptable finishes on high-FF/FL (e.g. trowel finish) floors. Based on the content and quality of the presentation, Cost was invited by ASCC to speak at the ASCC CELF 2023 event. Three self-explanatory slides that summarize the content and the recommendations from the Cost WOC and ASCC presentations are shown below: The second 2023 WOC presentation attended by the Hotline was sponsored jointly by WOC360 and ASCC, called "Quality in Concrete Slabs Luncheon and Forum: Preventing Problems with Slabs on Ground--Preconstruction Considerations When the Project Calls for a "Green" Floor". Moderated by concrete consulting firm Structural Services, Inc. (SSI), the panel included a petrographic analysis expert (Meredith Strow/Twining), a concrete contractor (ASCC member David Venegas/Vemac), and a cement industry technical sales engineer (Stephanie Hampton/Heidelberg Materials). Although this event was billed as a generic discussion of so-called "green" concrete slabs, the presentation quickly turned to a discussion of Type IL cement. This was indeed the hot topic of the event, and the panelists had obviously become very familiar with potential PLC side effects long before the Hotline became aware of them. Anyone who attended that 2023 WOC event can tell you straightaway about the question and follow-up comment this Hotline Operator posed to the panelists: "Some ASCC member contractors are losing money in both overtime and rework because this "new" material does not always perform as advertised. This change from ordinary portland cement to Type IL cement is not the concrete contractor's idea.  It is not our change. Who is going to reimburse the concrete contractors for the money we are losing in rework and overtime?" And the follow-up, memorialized by ASCC member Jason Wimberly on the social media platform LinkedIn: Shortly after the 2023 WOC event in January, the Hotline posted a PLC Frequently-Asked-Questions (FAQ) column in "Guidance #14" (Feb 2023 VOICE and the results of the ASCC member-only PLC survey conducted between Dec 2022 and Feb 2023 in "Guidance #15" (March 2023 VOICE). Both of those are available for members to read in the ASCC web page archives. Now here we are, some 15 months later after the publication of "Guidance #15". Much water has gone under the bridge since then related to Type IL cement. A fair amount of progress has been made, thanks to collaboration among ASCC members (and some non-members) from all across the concrete industry who have pitched in and generously donated their time, insights, and work product. But there is still work to do before we can get this one behind us and prepare ourselves for the next wave of alternative materials that the experts are telling us is on the near horizon (if not in use already). Part of that work includes collaborating with ready mixed and cement trade associations, encouraging adjustments to industry advertising campaigns and product messaging, which can lag behind the variety of customer field experiences as documented in several industry surveys, industry publications, events, seminars, and so on. The ASCC Hotline, for example, is still fielding calls from contractors--several here over the past few months--that report a recent epidemic of scaling problems across the midwest and upper midwest construction markets.  One publication that comes to us from the hallowed halls of academia explains the unusual 2023 epidemic--and its three root causes--as follows: Hotline Translation: Root cause #1: It is the concrete contractor's fault for not changing our long-standing, and customary finishing practices to handle PLC side effects in "the literature" e.g. changes in water demand, bleeding and setting time. Root cause #2: It was the weather's fault. Root cause #3: It was COVID-19's fault. During the pandemic, the academics claim, we lost our good finishers and were forced to hire unskilled replacements. Therefore, scaling is really the concrete contractor's fault for hiring substandard finishers. See Root Cause #1, above, or--better yet-- check out Gene Hackman and Keanu Reeves in "The Replacements". Once we move past the pedantic silliness of the above academic root cause dissertation, the scaling problems in the real concrete construction world are so bad for a few midwest states that some Owners are reportedly floating the idea of abandoning concrete as the paving material of choice and reverting back to asphalt concrete (AC) as the sole-source material option.  Obviously, these are not the kind of discussions we want prospective Owners to consider, let alone even having Owner or other stakeholder exposure to such talk as is currently being featured in newspaper articles, social media platforms, and even the excerpt from academia quoted above.  Well, there you have it--a modest look back at the past 29 episodes of the ASCC VOICE "Guidance" column. What will the next 30 episodes bring to ASCC VOICE readers? Stay tuned...we'll have to use the "trowel and error" method to rinse that one out. In the meantime, what follows below is the Hotline assessment of topics likely to be found listed in many current industry committee meeting agendas and event programs: finishability problems with commercial trowel finished concrete floor slabs, and how we must all collaborate together during the introduction of additional blended cements or SCM’s like ground glass into the concrete construction marketplace. ___________________________________________________________________ Big Thanks to the American Concrete Institute Anyone can see plain as day that the two most pressing topics facing the concrete construction industry today are related to Sustainability and the continued side effects of PLC. Viewed through a big-picture lens at 40,000 feet, it is also fair to say that the prime mover and facilitator in assisting ASCC--and the industry at large--to both collaborate and make progress with Sustainability and PLC challenges is the American Concrete Institute (ACI). (Insider's note: When it comes to ranking these issues in order of importance, it appears by far and away that Sustainability and PLC are the top two issues of concern to ASCC members (see estimate, below). The third topic, of course, is Constructability/Productivity. We will focus on Constructability and Productivity in more detail in future installments of the ASCC VOICE "Guidance" series.) Over the past 15 months, ACI has given a tremendous amount of encouragement and support, enabling ASCC to collaborate with ACI on the following Sustainability and PLC-related work products: -3 recent articles in Concrete International (Dec 2023, Jan 2024, Feb 2024); -The ACI Foundation sponsored the ACI 302-ASCC I/II to IL Slab Mix Study - Budgeted time for PLC discussions in ACI Committee meetings; -Hosting Special Sessions at ACI Conventions (see below); -Conducting a joint ACI-ASCC industry-wide PLC survey; -Hosting webinars and on-demand presentations through ACI University and -ACI participation in ASCC Sustainability (and other) Committee meetings. To put this all in perspective, we can try to estimate the impacts related to Sustainability and PLC on the concrete industry at large by examining the schedules of Special Sessions sponsored by ACI at Convention events. We simply count them--and observe the trends.  The table below is an approximate workup showing the past 8 ACI Convention events and the number of Sustainability and PLC Special Sessions offered at each. Note that there was a string of ACI Conventions that were cancelled as in-person events and held virtually (e.g. Oct 2020 Raleigh, N.C., Mar 2021 Baltimore, Md., and Oct 2021 Atlanta, Ga.). As can be seen in the table below, over a span of 8 ACI Conventions there were 29 Sustainability sessions and 16 PLC sessions.  If we keep in mind that there were multiple speakers who presented at some of the sessions--sometimes perhaps 5--that is an indicator of the large amount of diverse information and resources that ACI provides for the concrete industry at Convention events and a fairly good indicator of the industry importance of both Sustainability and PLC issues. Based on the flavor of recent Hotline calls regarding PLC and the progress made by ACI and ASCC on the Sustainability front, it appears the upward trend in ACI Special Sessions offered at future Conventions may continue. The forgotten trowel finish slabs: part 1 All concrete industry stakeholders need to be operating with the contractor's awareness of our ultimate collective objective--which is Owner satisfaction with the latest acquisition of a brand-new, custom-made, reinforced concrete commercial facility with a trowel finish floor as its centerpiece. In other words, it is entirely fair to say that during the so-called "roll-out" of PLC, not enough attention was paid to research, testing, and consulting concrete contractors for guidance concerning one of the most important bread-and-butter work products that many of our fellow ASCC concrete finishers routinely produce on a daily basis: high-spec, trowel finish concrete floor slabs. (N.B.: the phrase "collective objective" recognizes the easily and oft-forgotten fact that--as a collective group, all of us--architects, engineers, cement producers, ready mix producers, material suppliers, and ASCC concrete contractors-- all are ultimately working in service to...and at the pleasure of...the most important stakeholders of all: the Owners.) According to results of our recent joint ACI-ASCC PLC survey presented in the February 2024 issue of Concrete International, some 80 percent of Owners say concrete slab problems are occurring at a greater frequency with PLC than with OPC (ordinary portland cement). Many ASCC concrete contractors are currently contending with frustrated Owners who have high Quality demands--and expectations to be compensated if those demands are not met.  Indeed, for industrial distribution facilities, trowel-finished concrete floor slabs are not just the appearance centerpiece, but also serve as the durable working surface the Owners count on to generate revenue.  Any short-term or long-term concrete Quality issues that affect the Owner's ability to make money are certain to add to the concrete contractor's exposure as well. At a recent industry event, ASCC Vice President and Board Member Anthony DeCarlo reminded us of the perils of future roll-out miscues as follows: "The problem is that nobody seems to be looking at Type IL cement from a finishability standpoint. They don't realize the end-user Owners are actually looking at our trowel finish concrete floors as the showpieces of their new facilities. If we are producing concrete that can't be finished by traditional methods or finished to the level the Owners are expecting, then our industry as a whole is going to get a black eye". To put this in perspective for those who have never set foot on an active jobsite, DeCarlo brings his expertise as the CEO of a concrete contracting company to bear by defining what the term "traditional methods" means to an ASCC concrete contractor tasked with managing the finishing crews responsible for producing trowel-finished concrete floors required to meet very demanding Owner expectations: "It takes about 3 to 5 years to train a good concrete finisher. But if the cements keep changing--and the way these cements react during a slab placement keeps changing--how can anyone expect these finishers to be able to read the floor and decide what tools and machines need to go where...and when?  All the variability we are experiencing with Type IL is making it more difficult to train new finishers, makes experienced finishers concerned about their skills to produce an acceptable finish, and continues to increase the risk contractors bear." ___________________________________________________________________ Jewels in the Crown: Slab Owners...and their Consultants As ASCC contractors have reported, the most common PLC side effects occur when the contracted work products comprise trowel-finished concrete industrial floor slabs. As Anthony DeCarlo and other contractor CEO's will tell you, the trowel finished concrete floor slab is considered by many Owners to be the "Jewel in the Crown" of their new commercial facility. So for ASCC concrete finishers, the pressure is on. In today's construction environment, the current breed of Owners is not interested in flawed floors, they want perfection. To get a view through the lens of a concrete floor slab expert, we talked with long-time ASCC member Scott Tarr, PE, FACI, President of North S. Tarr Concrete Consulting, based out of Dover, NH. Scott Tarr is not a concrete contractor himself, but his work is well-known among the ranks of ASCC contractors.  Tarr co-authored the ASCC publication "Guide to the Design and Construction of Concrete Toppings for Buildings" with partners Ron Kozikowski and Matt Sheehan, and has recently produced a webinar for ASCC that covers "Slab on Grade Design Options". As a Fellow, Tarr's accomplishments at ACI range from author of articles, session presenter, and many years' worth of ACI Committee work. Tarr is also a forensic engineer, expert witness, and a Constructability consultant. To address the topic at hand, we asked Tarr to explain his role as Constructability consultant to several national, high-profile commercial building Owners. As an expert in the design and construction of high-spec, trowel finished concrete floor slabs, Tarr often has his hands full dealing with constant Owner expectation management, starting from initial meetings during the Owner's conceptual phase all the way through to project completion. Tarr explains it this way:  "It's a consultant's job to inform the Owner of what they reasonably should expect based on industry standards, the slab design itself, selection of concrete contractor, time of year, and so on." And what are these very competitive, high-profile Owners telling consultants like Tarr? One such Owner heads up a nationally recognized capital investment firm-- a successful group of investors at the top of the real estate food chain who lend cash to high-end developers in a highly competitive business arena. Before consulting on the schematic architectural design portion of a new company headquarters building, Tarr was given the following criteria by the Owner: "This will be our flagship headquarters building, and we expect the concrete floors to look like they're in a museum--so our customers know we pay close attention to details when they visit us". In another concrete floor consulting case, the company president brought Tarr in near the end of the design phase to review plans for one of the company's typical big-box, tilt-up shell structures--nothing fancy or spectacular--until you got inside to the concrete floor.  During a meeting with the Owner, the design philosophy was explained to Tarr thusly: "We realize that the construction documents do not specify the project itself to be "Architectural Concrete" per se, but at the end of the day, in order for us to be able to sell the building, it will come down to a beauty contest between our concrete floors and those of our competitors in our regional industrial real estate market". The third example cited by Tarr has some interesting twists.  The Owner in this case is a group of capital investors who specialize in all aspects of the co-called “big box” commercial facility business – design, build, buy, sell, renovate, flip.  In other words, these folks are simply in the business of buying and selling commercial real estate.  In what might be called astute gunsmanship, these investors themselves have become quite expert at performing their own in-house concrete slab condition surveys and using visible features to estimate future maintenance costs based on observable crack fields in concrete floor slabs.  If, for example, their in-house survey indicates just a few cracks, the building can command a higher price, since future maintenance costs could be projected to be minimal.  For this Owner, industrial concrete floors with crack fields become bargaining chips to be used in sales negotiations.  In one example, even though Tarr provided a report discussing the cause and proper repair of cracks, the capital investors used the visibility of the cracks (albeit repaired) to submit a $500,000 counteroffer, discounted from the listed selling price based on their in-house research and condition survey of the existing slabs in that market.  For this reason, excessive visible random cracking has become a sensitive issue for Owners. “As a consultant”, Tarr says, “I am obligated to advise my clients that any expectations of perfect, crack-free floors (or any cost analysis that does not include future floor maintenance costs) are not realistic and are not consistent with the preface that appears on the cover page of ACI 302.1R-15 Guide to Floor and Slab Construction.  I tell Owners that concrete contractors will always strive for perfect, defect-free floors, but perfection cannot be guaranteed with a natural product such as concrete.”  Reasonable expectations should be established, and effort should be made to minimize the number of visible defects.  Several industry guides, including ACI 302.1R section 5.2.9.3 and "Concrete Floors on Ground" published by the Portland Cement Association (PCA) include the following statement: "Some random cracking should always be expected, even with sufficiently close joint spacing.  It is reasonable to expect random visible cracks to occur in 0 to 3 percent of the surface area floor slab panels formed by saw-cutting, construction joints, or a combination of both." According to Tarr, “this expectation for a conventionally-jointed floor was developed to suggest to Owners that zero cracks is not realistic but also that cracking in more than 3% of the slab panels can be excessive.  While some feel 3% isn’t enough, we have found that cracking in less than 1% is common and 3% is a generous allowance.  In any case, for any random cracks, we recommend considering the location, length/width, and cause of each crack to determine its expected performance in order to develop an appropriate remedy.” ___________________________________________________________________ The forgotten trowel finish slabs: part 2 Since its formation in August 2023, the work of the ASCC PLC Task Group has had immediate, worthwhile benefits for ASCC concrete contractors and concrete industry stakeholders at large. Although the proceedings of the Task Group meetings largely remain unpublished, it is fair to report a consensus has been reached concerning two key points.  The first point is acknowledgement of the fact that the industry message of "1 to 1 replacement with no side effects" has been effectively debunked. The second point is recognition that the PLC product was brought to market before the often-reported side effects on trowel finished slabs (e.g. changes in set time, bleed rate, water demand, finishability, and so on) were fully understood by the material producers and communicated to concrete contractors and other stakeholders. In other words, introduction and increased use of  the "new" material have come with some unintended consequences. Industry event organizers have recognized this is currently a hot-button topic which has generated totally packed rooms at World of Concrete, ACI Conventions, and in-person ASCC events. Recent example: Anyone who attended any of the PLC-themed Special Sessions at recent ACI Conventions could see straightaway that the venue's rooms were not adequate to accommodate the standing-room-only crowds gathered there to learn about and discuss one of the more difficult questions posed to the concrete industry at large in recent memory:  "How can material suppliers introduce alternate cements into the marketplace and avoid unintended consequences at the same time?"  (N.B.: During one of the ACI Special Sessions offered at the recent ACI Convention in New Orleans titled "From the Lab to the Field--Experiences with Portland Limestone Cement, Part 1 of 2", the PLC conundrum was put into perspective by ASCC member Jason Wimberly, PE, FACI during a "Question and Answer" exchange with session moderator Stephanie Hampton. What follows below is a condensed, paraphrased account of that exchange.  For VOICE readers who are interested in listening to this Special Session in its entirety and in context (highly recommended by the Hotline), a recording was made by ACI and is--at present--available to ACI members who attended the New Orleans Convention on the YouTube platform via the ACI "On Demand" service). Toward the end of this ACI Special Session, Wimberly asked the panel group this question regarding R&D, pre-release mockup testing of PLC trowel finished slabs: "...How much side-by-side, full-scale testing...was done by the cement industry in partnership with readymix producers and concrete contractors...and does the cement industry, noting all the problems that have been very verbally addressed, have the intention of doing that (full-scale testing) when they begin to drop even new further supplemented cements onto the marketplace...?" The response was fielded by moderator Hampton--quite candidly, too--as paraphrased thusly: "...unfortunately, to my knowledge, definitely not in the Mid-Atlantic area...I think that was an oversight...I 'm just going to apologize to everyone on behalf of the cement industry.  It's one of those problems that--obviously--we want to try to work together, all playing in the same sandbox, but unfortunately, on my behalf, I can say in my area it (testing) was not done. Do I think such testing needs to be done? Most certainly. Do I think that's the best way to probably mitigate future situations? Most certainly." ____________________________________________________ ACI Past-Presidents: Checklists to the Rescue Based on what we all know today, it is fair to say that--as an industry--we cannot afford to repeat the "growing pains" associated with the previous development and roll-out of an alternative material.  Everyone agrees the process of bringing future alternate materials to market can--and must--be improved. But how--and by whom? Thanks to examples set by ASCC, ACI, NRMCA, and other industry collaborators, we believe we are now well on the way to assembling the components and framework needed to help solve a very complex set of problems. One resource we can leverage for guidance is the work product of ACI past Presidents.  For example, when it comes to defining the ACI Core Values of "Camaraderie, Consensus, and Credibility", we look to the landmark column by ACI past President James Jirsa, who was the first ever to discuss how to "play nice in the sandbox"--ACI Committee style.  Jirsa's October 2000 treatise describes something many of us have witnessed in person at ACI Committee meetings--rip-roaring fireworks coming from both sides of the aisle during contentious technical arguments. But--at the end of the day--consensus is reached, and no one drives home mad. If the problem set to be solved features issues of efficiency in reinforced concrete design and construction, we can consult with structural engineer and ACI past President Cary Kopczynski, or--even closer to home--ACI past President Mike Schneider, for guidance in matters of Constructability and Productivity.  Schneider is an ASCC Founding Member, and is reportedly one of the few concrete contractors elected President in ACI history. Schneider is also known for stating in a Constructability presentation "I've never seen email drive a single nail or place a yard of concrete". When considering the complexities of the comprehensive testing and vetting process required to appropriately develop and introduce new alternate materials into the concrete construction marketplace, we can make good use of the vast experience and published work product prepared by yet two more ACI past Presidents and ACI Honorary Members:  Terry Holland and Ken Hover.  Their piece of the puzzle?  A so-called "product data sheet". But viewed through the lens of ASCC concrete contractors, we see it as a thorough and sensible checklist--similar to the many ASCC checklists developed over the years in conjunction with the NRMCA and other concrete industry partners. Originally assembled by Holland and Hover to ensure appropriate material vetting, the suggested 64-item checklist appeared in their August 2020 ACI Concrete International article titled "Proposed Data Sheet for Alternative Cementitious Materials".  Aimed by the authors at an intended audience of prospective material suppliers, the checklist is designed to make sure all relevant project stakeholders are consulted before a new material can be brought to market.  Simply put, concrete producers, architects, engineers, and most important--concrete contractors--must be included in the conversation in order to be considered for use in a project. Presented in generic fashion, the proposed checklist "incorporates questions based on more than 100 years of experience with concrete materials, including the SCM's (supplementary cementitious materials) that are in common use today". A portion of that "100 years of experience" cited above includes the efforts behind the introduction of silica fume into the marketplace during the 1990's. At that point in his career, Holland was involved in those efforts from the silica fume proponent side of the aisle.  "Engineers kept asking us for data to support our proposals that silica fume material be incorporated into their structural designs", Holland recently explained to the Hotline, "If we had a checklist like this back then, obtaining acceptance would have been a whole lot easier to introduce the new silica fume product to the marketplace." Although the article is aimed at potential material suppliers, the authors tell us that the checklist will provide information of interest to Owners and building officials as well: "The Owner must be made aware of the use of the proposed material and of the risks and benefits the material presents. The building official must be comfortable that the material will perform as intended and provide the appropriate level of life safety for the project". The proposed ACI checklist itself is drawn straight out of the classic "Constructability" playbook, which--by industry consensus definition--stresses early involvement by project stakeholders as the course of action recommended to greatly improve the chances of project success. As described above, the alternate material checklist itself contains 64 line items, distributed over 7 separate categories: General, Concrete Production, Contractor Considerations, Structural Considerations, Durability Considerations, Sustainability Considerations, and Considerations for the Architect. Of those 7 categories, the sections that concern ASCC concrete contractors (Part C) and architects (Part G) are excerpted below: It seems sensible that the ASCC and our other industry partners could incorporate the Holland and Hover checklist into our playbook, which already includes Alert! #1, Alert! #2, the ASCC-NRMCA Preconstruction Conference checklist, and if it is a performance-only specification, then the ASCC-NRMCA P2P checklist.  Considering all 5 documents together, then, all the right boxes could be checked--and all the right questions could be asked--to provide the best chances of success when the next alternate cementitious material comes rolling down the chute. The forgotten trowel finish slabs: part 3 Many of the accounts concerning the potential PLC side effects experienced with trowel finished concrete floor slabs (e.g. set time, bleed water, water demand, and finishability) have been disclosed during ASCC Hotline calls without benefit of photograph--or video--documentation.  Largely driven by NDA (non-disclosure agreement) restrictions, many of us are forced to rely on verbal or written descriptions to help us visualize how the reported side effect symptoms would actually appear in the field.  Until now, that is.  Thanks to several ASCC contractor members, a few video clips have been generously made available for inclusion in this 30th Anniversary edition of the VOICE "Guidance" column. The first video clip comes from long-time ASCC contractor member Steve Lloyd, FACI. In this 17-second video clip, the concrete finisher is seen checking surface crusting by using finger pressure when slab cracks appeared while the floor slab was still being trowel finished. This indicates the slab is setting up from the top, down--the opposite of what concrete finishers have been trained to recognize and have typically experienced with OPC over many years of trowel finishing concrete. Here's a Dropbox link to the Lloyd video described above: https://www.dropbox.com/scl/fi/q0bt6tzzau93twj9aksf9/Stevie-Lloyd-clip-1.mp4?rlkey=dl1t1fsjtzg0sxpg45w0ntnse&st=xsy0mtcl&dl=0 The next 2 video clips come from long-time ASCC contractor member Joe Neuber, FACI. Both clips were filmed during the mockup test placements #2 and #3 that were presented in the January 2024 article in ACI Concrete International; co-authored by Neuber and titled "Minimizing the Risk for Portland-Limestone Cement Concrete Slabs". In the video clip filmed for mockup #2, a finisher is seen checking surface crusting using finger pressure, similar to the Lloyd example, above. In the video clip taken during mockup test pour #3, severe cracking and surface crusting is evident. Dropbox links to the Neuber mockup test video clips described above are here: https://www.dropbox.com/scl/fi/x3zzheb6ao7cz82soicmg/Neuber-test-pour-2.MP4?rlkey=e9a05y3px7thax5obx8ox7mb1&st=8c5jkieg&dl=0 https://www.dropbox.com/scl/fi/yhwyhk7d4isga2s5jbm3a/Neuber-test-pour-3.mp4?rlkey=24gy9r10t6f1lhzw0rer6xqrq&st=4c1su9a1&dl=0 The final video clip comes to us from an ASCC Hotline caller, filmed during a placement of PLC concrete intended to receive a follow-on dry-shake treatment as part of the finishing process.  Even though the clip is a mere 8 seconds long, that is really all that is needed to demonstrate what some PLC forensic experts call the "apple pie crust" side effect, another indicator of a concrete slab setting from the top, down. (N.B.: Perhaps unknowingly giving away their age, other long-time concrete finishing experts have told the Hotline this 8-second clip is graphic evidence that showcases the "waterbed" effect.) The Dropbox link to the classic PLC "waterbed" video clip is here: https://www.dropbox.com/scl/fi/iw2hric0m754sdfw4pm3e/Hotline-PLC-waterbed.mp4?rlkey=htll6eq62xzj9z8qvwg0xw4v7&st=8gysix8x&dl=0 (Insider's note: Of course, not every trowel-finished concrete floor slab that features PLC in the mix is going to exhibit such finishability challenges as those documented above. But the next time you hear  an experienced ASCC concrete contractor speak of problems with water demand, or lack of bleed water, or "apple pie" surface crusting...at least now you will be able to visualize straightaway the side effects the concrete finisher is describing.) Ray Hefner Wed, 10 Jul 2024 18:06:00 GMT f1397696-738c-4295-afcd-943feb885714:469 https://ascconline.org/Home/News/articleType/ArticleView/articleId/468/On-Site-Medical-Support-3-Methods-to-Treat-Injured-Workers-Without-Leaving-Site#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=468 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=468&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/468/On-Site-Medical-Support-3-Methods-to-Treat-Injured-Workers-Without-Leaving-Site On-Site Medical Support: 3 Methods to Treat Injured Workers Without Leaving Site Reid C. Lenhart CSP, Senior Safety Director, Concrete Strategies In the modern construction era, contractors are placed under the microscope through rigorous pre-qualification processes set in place by general contractors, ownership groups, and clients. Lagging indicators such as OSHA Recordable Rate, DART Rate, and EMRs are ways in which a company’s safety performance is reflected in past performance and can ultimately make or break the decision of being awarded the work. Contractor-Controlled and Owner-Controlled Insurance Programs (CCIP / OCIP) tend to favor contractors with lower lagging indicator rates as it lessens their exposure and risk on the project. Potentially an organization’s lagging metrics are its Achilles Heel in securing more work. How can an organization improve its position and performance going forward to remain competitive? The answer may only be a phone call away. As contractors we bring everything to the job site: materials, equipment, and our workforce, but why in the instance of a non-life-threatening injury do we take an injured worker off-site? There are multiple ways in which an injured employee can receive an evaluation and receive the appropriate level of care without ever having to leave the project. Depending on several factors such as budget, location, and project duration, here are 3 ways in which to provide care to an injured team member without ever having to leave the job site. 1.) Telephonic Occupational Medicine Triage Telephonic Medical Triage is by far the most cost-effective and accessible way of assessing and caring for an injured employee with a minor non-life-threatening injury. There are multiple services available that after an account is established, a 1-800 number is made available, and wherever there is phone service, a Registered Nurse or Doctor is on the other end of the line ready to assess the injured employee and provide care recommendations. These care instructions are also provided via email or text to the employee as well and allow for follow-up calls along with the First Aid case management. If the injury is more serious, the nurse or doctor will recommend that the employee be taken to the Occupational Medicine Clinic or Emergency Room. It is important to note that some of these telephonic services provide translation services so the worker can have a conversation in their native tongue. For additional documentation, the calls can be recorded, and that information utilized later if needed by a doctor or claims manager. 2.) Mobile Medics Mobile Medics are available in select markets across the country and are becoming more popular due to demand. These organizations are staffed by medical professionals with extensive training such as paramedics, EMTs, registered nurses, and physicians. The professionals are on call and usually stationed less than a couple of hours away from the job site. Paired with formal medical training and experience, these responders are also trained specifically in OSHA recordability. They are equipped with a jump bag containing First Aid care items only, ensuring that care given past First Aid is not provided possibly resulting in an OSHA Recordable on-site. Telephonic triage is typically a part of the service to aid in the overall case management of the injury while the medic is being dispatched to the site. 3.) On-Site Medical Professional On-site medical professionals over the last 5 to 10 years have become more visible on large-scale, high-profile, and long-term construction projects. Given this is the most expensive of the three solutions, typically having a full-time on-site medical professional is driven and paid for by the general contractor or the owner. Like mobile medics, these medical professionals range in education and experience from RNs to MDs. There are multiple advantages such as instant access to care, easily accessible follow-ups, and consistent case management by the same treating medical professional. Other services usually offered by on-site medical professionals may include drug and alcohol testing, respirator fit testing, and wellness coaching. It is vital to remember when an injury occurs that we are construction professionals and that initial triage is key, but enrolling medical professionals will enhance the level of care and treatment of our injured workers. Furthermore, engaging a medical professional service alleviates mismanagement of care by a supervisor, it also builds trust with the worker that the company engages an outside medical professional source to provide a non-biased evaluation. An injured team member must receive the appropriate level of care for the injury that they have sustained. Experience has shown us that Emergency Rooms and Non-Occupational Medicine Clinics do not always understand the intricacies of OSHA Recordability and that their over-treatment of the injury has an impact on the organization on a broader spectrum. Employers can entrust the care of their injured team members together with the overall organization’s metrics to these types of occupational medical responders who understand the complexities of care and OSHA Recordability. Ray Hefner Tue, 09 Jul 2024 20:52:00 GMT f1397696-738c-4295-afcd-943feb885714:468 https://ascconline.org/Home/News/articleType/ArticleView/articleId/467/Summer-is-Swimming-Pool-Season-Is-it-a-Saltwater-Pool#Comments 0 https://ascconline.org/DesktopModules/CM.NewsArticles/RssComments.aspx?TabID=190&ModuleID=463&ArticleID=467 https://ascconline.org:443/DesktopModules/CM.NewsArticles/Tracking/Trackback.aspx?ArticleID=467&PortalID=3&TabID=190 https://ascconline.org/Home/News/articleType/ArticleView/articleId/467/Summer-is-Swimming-Pool-Season-Is-it-a-Saltwater-Pool Summer is Swimming Pool Season: Is it a Saltwater Pool? Rich Cofoid, Council Director Summer is swimming pool season. For a sealer manufacturer, it is also the season for increased tech calls about sealers used on decorative pool decks. Amongst the various pool water sanitation methods (chlorine, UV, ozone, and salt), the salt method is the fastest growing, whether it’s new builds or folks replacing traditional chlorine equipment for the saltwater chlorination method. The advantages of a saltwater pool are many: fewer chemicals are used, so lower chemical costs, it's better for your skin and hair, easier on towels and swimsuits, lower maintenance, and more. However, what many people fail to realize is the corrosiveness of the salt water. It is not just hard on outdoor furniture and pool fixtures, but it can wreak havoc on your pool deck, whether it is natural stone or concrete. This week alone (and it is Tuesday as I write this) I have fielded three calls about supposed sealer failure- sealer delaminating. The first question I ask after I’m told it is a pool deck is “Is it a saltwater pool”? All three cases this week have been YES. So, why don’t acrylic sealers stand up to salt? They do! It is not the sealer but the concrete under the sealer that causes most issues. The problems typically start around a control joint or where the concrete slab meets the pool coping. Usually, it is worse (or first noticed) when people get out of the pool as the saltwater drips off the body. Whether it’s a control joint or a small crack or pinhole in the film of the sealer, salt water eventually migrates under the sealer it starts attacking the concrete underneath. When the concrete deteriorates it brings the sealer with it. The delamination spreads with time. It is not so much a sealer problem as it is a concrete problem, or a saltwater meets concrete problem. So, what’s the fix? First, be aware of potential issues and ask the client what you are dealing with before you begin a decorative project. If it’s a saltwater pool, you might want to have a disclaimer in your contract (I’m no lawyer, so not legal advice, just a suggestion). Next, we have found the best sealer is either a penetrating sealer, like a silane or siloxane, or a combination of penetrating sealer with a solvent-based acrylic. If you use this combo, the acrylic must be solvent-based as the penetrating sealer will prevent a water-based acrylic from sticking. If you are working in a state with strict VOC regs, then this combo won’t be an option for you, sorry. We run across this phenomenon with spray down/knock down systems as well. The saltwater gets under the sealer AND texture, attacks the concrete, and everything delaminates. As always, check with the manufacturer of your decorative chemistry before beginning a saltwater pool deck to ascertain their recommendations. Ray Hefner Tue, 09 Jul 2024 20:46:00 GMT f1397696-738c-4295-afcd-943feb885714:467