Fly ash in concrete - technical considerations

The increase in uses of fly ash in ready-mixed concrete and concrete products during the past 10 years indicates a greater acceptance of it as a mineral admixture for Portland cement concrete. In producing concrete of a specified quality, it is important that the fly ash selected be of a good and consistent quality. This article presents information on factors affecting the quality of fly ash from a single source. The author focuses on technical considerations for the specifier and the ready-mix producer. Laboratory test data are presented to illustrate the distinct relationships between Class C and Class F fly ash characteristics and their performance in concrete. 5 references.