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.