CEMENT ADMIXTURE, CEMENT COMPOSITION, AND CEMENT CONCRETE MADE THEREFROM

摘要

A cement admixture which is reduced in the burden to be imposed on the environment,is effective in diminishing hexavalent chromium,is reduced in slump loss and heat of hydration,is less apt to be neutralized,and can be reduced in self−shrinkage.The cement admixture comprises an air−cooled blast furnace slag powder which consists mainly of a melilite and has a CO2 absorption of 2% or higher and an ignition loss of 5% or lower.In the powder,the content of sulfur not in the form of sulfuric acid is 0.5% or higher and/or the concentration of non−sulfuric−acid−form sulfur which dissolves away is 100 mg/L or higher.Preferably,the powder has a degree of vitrification of 30% or lower,a melilite lattice constant,a,of 7.73 to 7.82,and/or a Blaine specific surface area of 4,000 cm2/g or larger.