Findings from a two-year research project, “New Technology-Based Approach to Advance Higher Volume Fly Ash Concrete with Acceptable Performance,” provide concrete practitioners new testing data to justify increasing portland cement substitution in many mix designs
Source: National Ready Mixed Concrete Association, Silver Spring, Md.
Findings from a two-year research project, “New Technology-Based Approach to Advance Higher Volume Fly Ash Concrete with Acceptable Performance,” provide concrete practitioners new testing data to justify increasing portland cement substitution in many mix designs. Observing tests on high-volume fly ash concrete specimens, investigators observed that 1) higher in-place temperatures due to structural elements’ mass characteristics resulted in increased early age-in-place strengths, adequate for construction scheduling, as measured by match-cured cylinders, pullout testing and the maturity approach; 2) field-cured cylinders underestimated the in-place strengths, whereas standard-cured cylinders must not be used for estimating in-place strengths; and, 3) a maturity-based approach is applicable to estimate early-age strength in specimens or structures cast with fly ash-rich mixes, and potentially affords increased ash content without negative impact on construction operations.
“Use of recycled materials such as fly ash is one of the many ways the concrete industry can continue to be more sustainable, says George Gregory, chairman of the NRMCA-aligned RMC Research & Education Foundation, which funded the research with the U.S. Department of Energy through the Combustion Byproducts Recycling Consortium. The report findings will allow the industry to utilize more fly ash while ensuring that concrete remains a high-quality, high-performance building material. Adds Foundation Executive Director Julie Garbini, This project is an excellent example of what can be accomplished through partnership between industry organizations and the federal government. The study is available for download at the Foundation’s website, www.rmc-foundation.org, and included on the Research Supporting Sustainable Development CD.