| 摘要 |
PROBLEM TO BE SOLVED: To obtain high strength cement; concrete by containing an admixture, which contains aluminum sulfate, a sulfite and a polycarboxylic acid based water reducing agent, and cement. SOLUTION: The cement admixture is prepared by incorporating 1-7 pts.wt. aluminum sulfate necessary for improving the strength exhibition property expressed in terms of anhydride, 0.1-1 pts.wt. sulfite and 0.1-2 pts.wt. polycarboxylic acid based water reducing agent having cement dispersion effect, water reducing effect and fluidity holding effect to 100 pts.wt. cement. As the polycarboxylic acid based water reducing agent, a copolymer (I) composed of a structural unit expressed by formula I (R represents H or a 1-5C alkyl group), formula II and formula III and having 10-60 mol oxyethylene unit per 1 mol carboxyl group in the copolymer and the molecular weight of 5,000-100,000 or the one prepared by blending 50-100 pts.wt. copolymer (II) composed of a structural unit expressed by formula IV and having a molecular weight of 5,000-100,000 to 100 pts.wt. copolymer (I) is used. |
