| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cement admixture capable of decreasing slump loss at a high temperature, and increase of the adding amount at a low temperature, and having small temperature dependence of water-reducing properties by using a copolymer salt obtained by neutralizing a copolymer containing an oxyalkylene group with an alkaline material as an essential component. SOLUTION: This cement admixture comprises a salt of a copolymer obtained by neutralizing the copolymer having 1-98 wt.% structural unit of formula I, 1-98 wt.% structural unit of formula II [R<1> O and R<3> O are each a mixture of one or more kinds of 2-18C oxyalkylenes with the proviso that in a case of two or more kinds, the oxyalkylenes can be added to each other to form a block or random shape; (m) and (n) are each an average number of addition mols of oxyalkylene and >=10; R<2> and R<4> are each a 1-30C aliphatic or alicyclic hydrocarbon] and 1-45 wt.% structural unit of formula III R<5> to R<7> are each 11, methyl or (CH2 )p COOX [X is H, a monovalent metal, a divalent metal, ammonium or an organic amine; (p) is 0-2]; with the proviso that when two COOX groups are present, the COOX groups can foam anhydride} with an alkaline material. |
