| 摘要 |
PURPOSE:To obtain a cement composition capable of maintaining flowability for a long time by using a specified compd. obtained by introducing an unsaturated carboxylic acid into the condensate of an aromatic hydrocarbonsulfonic acid and formaldehyde as the cement admixture. CONSTITUTION:This cement admixture is a compd. having a structural unit shown by formula I [A is shown by formula II, B is a 1 to 3-membered-ring aromatic hydrocarbonic group, X is SO3M (M is H, alkali metal or alkaline- earth metal) directly joined to the aromatic ring, R is alkyl, Y is COOM (M is H, alkali metal of alkaline-earth metal), (m) is 0 to 2, (n) is 0 to 4, (p) is 1 to 20, and (q) is 0 to 20], the content of SO3M is controlled to 10-35wt.% that of COOH to 5-20wt.% and the SO3M-to-COOH molar ratio to 1:1 to 2:1. The admixture is added by 0.01 pts.wt. to 100 pts.wt. of cement and 25-500 pts.wt. of water to obtain a cement composition capable of maintaining flowability for a long time. |
