Polycarboxylic acid-based copolymer, concrete admixture, and concrete composition

摘要

Provided is a polycarboxylic acid copolymer capable of achieving, in a well-balanced manner, an excellent viscosity reduction effect, excellent pipe passing properties, and excellent water reduction properties, in a hydraulic powder-containing composition. Also provided is a concrete admixture including said polycarboxylic acid copolymer. Also provided is a concrete composition including said concrete admixture. This polycarboxylic acid copolymer includes, relative to 100% by mass of all structural units: 35%–88% by mass of a structural unit (I) derived from an unsaturated polyalkylene glycol monomer (a) indicated by a specific general formula; 1%–35% by mass of a carboxylic acid structural unit indicated by a specific general formula (II); and 11%–30% by mass of a carboxylic acid alkyl ester structural unit indicated by a specific general formula (III).