| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amt. of a polycarboxylic acid-base water-reducing agent to be added and to suppress the lowering of flowability over a longer time by using Portland cement having a specified water-soluble alkali content. SOLUTION: A hydraulic binder comprising Portland cement having <=0.25%, preferably 0.1-0.2% water-soluble alkali content is blended with a polycarboxylic acid-base water-reducing agent having an average mol.wt. of 1,000-50,000 and, optionally, fine and coarse aggregates and additives such as an air entrainer and a defoaming agent. The water-reducing agent may be selected from a polyacrylate, a polymethacrylate, a copolymer of acrylic acid and an allyl ether, a copolymer of anα-olefin and an ethylenically unsatd. dicarboxylic acid and its water-soluble salts prepd. by partial esterification, partial amidation and partial imidation. The flowability of the resultant hydraulic blend can be maintained over a long time. |
