Methods of producing concretes containing class C fly ash that are stable in sulphate environments

摘要

Methods for combining Class C fly ash into cementitious mixtures for producing concretes that are resistant to sulfate-containing environments. In one method, Class C fly ash is intergound with portland cement clinker and gypsum to produce a cementitions mixture, which, when combined with water and an aggregate produces a hardened concrete that is resistant to sulfate environments. Alternatively, portland cement clinker and gypsum are first interground and the resultant mixture is admixed with Class C fly ash to produce a cementitious mixture. Thie cementitious mixture, in combination with water and an aggregage, produces a hardened concrete that has improved resistance to sulfate environments. In other aspects, a concrete that is stable in sulfate environments is produced by admixing portland cement, Class C fly ash and water containing a source of ions selected from the group consisting of sulfate and hydroxyl anions. The resultant concrete is capable of hardening in sulfate environments without the formation of such quantities of volume-expanding compositions in the hardened concrete as would cause the hardened concrete to undergo stress failure.