Cement; Fly ash; Materials selection; Materials tests
Supplementary cementitious materials (SCMs) are a critical component of many concrete mixtures, with Class F fly ash being the most widely used in Texas because it reduces concrete cost and improves long-term strength and durability. Increasingly, power plants are blending coals, producing fly ash with potentially different properties than the previously common Class F fly ash from Texas lignite coal. Further, fly ash suppliers can blend fly ashes from different sources and are increasingly interested in reclaiming ashes from landfills and remediating ashes that do not meet specifications. The changing landscape for fly ash demands rigorous testing to ensure that the fly ashes still perform as expected based on their ASTM C618 Class F classification. This project will evaluate a variety of fly ashes from blended, reclaimed, and remediated sources for chemical and physical characteristics and performance in cement paste, mortar, and concrete mixtures. In addition, since ASTM C618 has been shown to be inadequate for qualifying SCMs, new tests will be developed and evaluated to characterize the reactivity of SCMs and their performance in concrete.