Technical

Jim Klinger, Concrete Construction Specialist, The VOICE Newsletter December 2023 Full Disclosure: Perhaps one of the most unwelcome telephone calls a concrete construction project manager could ever get usually comes first thing the Monday morning following a Friday foundation concrete placement that required setting of large anchor rod assemblies for follow-on steel buildings. Such phone call...

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Mike Hernandez, Technical Director, The VOICE Newsletter, December 2023 ASCC just issued Alert! #2 on portland limestone cement (PLC) (members click here to view). In it, ASCC recommends two tests, one for bleed rate and one for initial set. Because reduced bleed is a common issue raised about PLC, this test was recommended, per ASTM C232. One response from experts regarding our recommendations...

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Jim Klinger, Concrete Construction Specialist The Voice Newsletter November 2023 Question: We are building a large, 6-story reinforced concrete parking structure with a footprint of 113,832 gross square feet (GSF). Typical slab thickness is 7 inches, post-tensioned (PT), normal weight concrete (NWC). The building geometry is such that there are very few level slabs; typically, those are loca...

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Mike Hernandez, Technical Director The Voice Newsletter November 2023 ASCC members continue to work on numerous ACI Committees to monitor and influence the documents and present the contractor’s position. There are ACI committees on nearly any subtopic in concrete you can imagine. ASCC/ACI members have provided feedback on the work happening in the committees in which they are involved. F...

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Jim Klinger, Concrete Construction Specialist The Voice Newsletter October 2023 Full disclosure: Sometimes it takes a bit of background confected with lore borrowed from other structural building trades to help illustrate obliquities particular to our own concrete trade. As it turns out, this right here is a classic example of that. To oversimplify enormously, any time a licensed design pro...

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Mike Hernandez, Technical Director The Voice Newsletter October 2023 The maturity method for estimating in place strength of concrete has been around for decades. It is useful for timing the start of post-tensioning unbonded cables and for removing formwork under elevated decks. A concrete mix can be correlated to make a time-temperature strength curve. This is quite helpful in the winter month...

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Jim Klinger, Concrete Construction Specialist The Voice Newsletter September 2023 Question:  We were recently awarded the subcontract for a reinforced concrete high-rise tower that features 3-ft thick shear walls with moderate to heavy reinforcing steel congestion. The shear walls in some sectors are up to 4-ft thick. This upcoming project has a fast-track schedule, the so-called "3-d...

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Mike Hernandez, Technical Director The Voice Newsletter September 2023 Several years ago, climate change and sustainability were not something the concrete construction community would hear much about. Now action on sustainability is increasing all around us, which translates to less cement in concrete and more supplemental cementitious materials. In the last few years, the following has occurr...

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Jim Klinger, Concrete Construction Specialist The Voice Newsletter August 2023 Question: We are building an addition onto a small commercial steel building.  The vertical supports for the elevated work consist of relatively light structural steel columns that sit on concrete footings, each with footing dimensions 2 ft long by 18 inches wide by 12 inches deep. Our submitted mix design is 30...

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Mike Hernandez, Technical Director The Voice Newsletter August 2023 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 Station The most accessible technology may be to inves...

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