CEMENT ADMIXTURE AND CEMENT COMPOSITION

摘要

PURPOSE:To provide the cement compsn. which shrinks less in an initial period by using the expandable admixture having a specific surface area. CONSTITUTION:This cement admixture consists essentially of the expandable admixture having >=2m<2>/g specific surface area and superfine powder. The expandable admixture is ground to >=2m<2>/g specific surface area and is an haveyne ore system, CaO system, calcined alum system, Ca aluminate and CaSO4 mixture system which are crystalline or amorphous or the mixture composed thereof, and CaSO4 system, which are the expandable hydrate in reaction and form ettringite and Ca(OH)2, and also includes iron powder, etc., which form hydroxide. Among these materials, the haveyne system and the CaO system are more preferable in terms of safety. The silica dust and siliceous dust to be byproduced at the time of production of silicon, silicon-contg. alloy, zirconia, etc., are adequate as the superfine powder and CaCO3, silica gel, Al2O3 etc., are usable as well.