Cement additive and cement composition

摘要

A cement additive contains industrial waste and has the effect of inhibiting formation of monosulfate in a hardened cementitious material. The cement additive contains specifically calcium carbonate, gypsum and coal ash and/or blast-furnace slag powder. This enables efficient use of industrial waste, allows inhibiting monosulfate formation in the hardened cementitious material, and allows producing a hardened cementitious material having good durability (sulfate resistance).