NRMCA completes two-year fly ash study

Silver Spring, Md.—The National Ready Mixed Concrete Association (NRMCA) completed a two-year research project titled "New Technology-Based Approach to Advance Higher Volume Fly Ash Concrete with Acceptable Performance." The primary findings of the study include the following:

• For high-volume fly ash (HVFA) concrete, higher in-place temperatures due to the mass characteristics of structural elements resulted in increased early age-in-place strengths, adequate for construction scheduling, as measured by match-cured cylinders, pullout testing, and the maturity approach.
• Field-cured cylinders underestimated the in-place strengths where as standard cured cylinders must not be used for estimating in-place strengths.
• A maturity-based approach is applicable to estimate the early-age concrete strength in structures made with HVFA concretes. Such an approach will allow for possibly increased content of fly ash without negative impact on construction operations.

This project was funded by the Department of Energy through the Combustion Byproducts Recycling Consortium and the RMC Research & Education Foundation. The complete report can be downloaded from NRMCA’s Web site.