ADMIXTURE FOR CONCRETE

摘要

PROBLEM TO BE SOLVED: To obtain an admixture for a concrete improving a separating resistance of materials, an initial strength, etc., by specifying a blending ratio of a copolymer, a high quality water reducing agent, a water-soluble polymer and a defoaming agent, a molar ratio of monomers forming the copolymer and the average molecular weight of the copolymer. SOLUTION: This admixture for a concrete is prepared by blending 100 pts.wt. mixture comprising a copolymer, a high quality water reducing agent and a water-soluble polymer having a ratio of (35-90) to (5-40) to (5-60), (with the proviso that the total thereof is 100 pts.wt.), with 0.01-30 pts.wt. defoaming agent. The copolymer is obtained by copolymerizing monomers of formula I and II. The molar ratio of the monomer of formula I to that of formula II is (1/90) to (50/50). A weight average molecular weight (measured by a gel- permeation chromatography method and reduced to a sodium polystryrenesulfonate) is 3,000-200,000. An aromatic water reducing agent is used as the high quality water reducing agent. A polyalkylene glycol derivative is used as the water-soluble polymer. A product having an excellent surface appearance is obtained by using the admixture for the concrete.