Selective Dissolution of Portland‐Fly‐Ash Cements

Abstract

Many cement manufacturers are producing an interground or blended portland‐fly ash cement. The consumer is interested in establishing the quality of the blended cement being purchased. Of concern to most consumers is the quantity of fly ash in the blend. The European Committee for Standardization has developed a reference method for determining the fly‐ash content of blended cements. A variation of that method was used to evaluate the insoluble residue of type I, type II, gypsum, class F, class C, hand‐blended cements, and an industrial interground blended cement. The selective dissolution method is very reliable in its prediction of the amount of class F fly ash blended with portland cement. The results from the selective dissolution procedure indicate that 96% of class F fly ash is insoluble and that only 9% of the portland cement is insoluble. The standard deviation for each result is less than 2%. With the selective dissolution procedure presented the amount of fly ash in a blended cement can be accurately predicted.