Additives for cement

Abstract

An additive for cement comprising, as the effective component, a copolymer of a polyoxyalkylene derivative represented by following formula (1) and maleic anhydride, a hydrolyzed product of the copolymer, or a salt of the hydrolyzed product; ##STR1## wherein Z represents a residue of a compound having a hydroxy group, said compound having from 2 to 8 carbon atoms; AO represents an oxyalkylene group having from 2 to 18 carbon atoms; X represents an unsaturated hydrocarbon group having from 2 to 5 carbon atoms or an unsaturated acyl group having from 2 to 5 carbon atoms; R represents hydrocarbon group having from 1 to 40 carbon atoms; a represents 0 to 1,000; b represents 0 to 1,000; c represents 0 to 1,000; l represents 1 to 7, m represents 0 to 2; and n represents 1 to 7; l+m+n=2 to 8, m/(l+n).ltoreq.1/2, and al+bm+cn.gtoreq.1.

Dependencies are inferred from the claim text.