JPH05238795

PURPOSE:To provide the cement admixture effective for improving the dispersibility, suppressing a slump loss and improving strength and durability to a cement compsn. by consisting this admixture of a copolymer of a polyalkylene glycol diester monomer having an unsatd. bond and a monomer contg. a dissociation group and/or the metal salt thereof. CONSTITUTION:This cement admixture consists of the copolymer of (1) the polyalkylene glycol diester monomer having the unsatd. bond and (2) the monomer having the dissociation group and/or the metal salt of this copolymer. The monomer (1) includes, for example, the monomer of formula I. In the formula I, R , R , R , R denote hydrogen, methyl group, (CH2)m3C0OM , [(CH2)m4COO]2 M , etc.; where AO denotes 2 to 3C oxyalkylene group; m1 to m4 denote an integer from 0 to 2; n1 denotes an integer from 3 to 500; M denotes hydrogen, univalent metal, etc.; M denotes a bivalent metal. The dissociation group of the monomer (2) is >=1 kinds of formulas II and III (n is O or 1; X is hydrogen, univalent metal, etc.).