| 摘要 |
PROBLEM TO BE SOLVED: To obtain a concrete admixture enabling improvement in effects for reducing the viscosity of ready-mixed concrete and for retaining the flowability of the ready-mixed concrete by copolymerizing a specific monomer with a polyalkylene glycol monoester monomer and an acrylic acid-based monomer and/or an unsaturated dicarboxylic acid-based monomer. SOLUTION: This concrete admixture comprises a copolymer having a mol.wt. of 8,000-1,000,000(converted into polyethylene glycol) and produced by copolymerizing 0.1-80 mol.% of a monomer of formula I [X is a group of formula II, III, IV or V; R1 and R2 are each H or methyl; R3 and R4 are each a 2-4C alkylene; M1 -M4 are each H, an alkali(ne earth) metal, (alkyl)ammonium or a substituted ammonium] with 0.1-50 mol.% of a polyalkylene glycol monoester monomer of formula V1 [R5 and R6 are each R1 ; (m) is 0-2; AO is a 2-3C oxyalkylene; (n) is 2-300; X is H or a 1-3C alkyl] and 0.1-98 mol.% of an acrylic acid-based monomer and/or an unsaturated dicarboxylic acid-based monomer of formula VII [R7 and R8 are each R1 ; M5 and M6 are each M1 ; (m2 ) is 0-2]. |
