ABSTRACTThe objective of this summary is to report on work in progress that is examining parameters, measurable through chemical and XRD analyses, that could indicate whether a fly ash will enhance, degrade or have no effect on the sulfate resistance of fly ash concrete.Mehta [1–4] has discussed the factors that contribute to attack of sulfates on fly ash concrete. As noted in his review paper on this subject in the preceding volume in this series [1], the agents responsible for concrete expansion and cracking are alumina-bearing hydrates, such as calcium monosulfoaluminate and calcium aluminate hydrate, that are attacked by the sulfate ion to form ettringite, calcium trisulfoaluminate. Acidic type interactions between sulfate ions and calcium hydroxide also lead to strength and mass loss.
