Concrete admixture and preparation method thereof

The invention relates to a concrete admixture and a preparation method thereof. Unsaturated alcohol polyethers with different molecular weights are used as reaction raw materials to carry out copolymerization reactions with unsaturated carboxylic acid compounds; and then the obtained polymer is added into supplemented carboxylic compounds to carry out copolymerization reactions to obtain a polycarboxylic acid concrete admixture, which has long polyoxypropylene ether branched chains and short polyoxypropylene ether branched chains at the same time. The concrete admixture has a good initial performance and delayed coagulation slump retaining performance, and compared with the prior art, a better technical effect is achieved. 本发明涉及一种混凝土外加剂及其制备方法。本发明提供了一种分别以不同分子量不饱和醇聚醚为反应原料与不饱和羧酸类化合物进行共聚反应，再将上述聚合物与补充加入的羧酸类化合物进行共聚反应，合成同时具有同时具有长聚氧丙烯烯醚支链和短聚氧丙烯醚支链的聚羧酸类混凝土外加剂，该类混凝土外加剂兼具良好的初始性能和缓凝保坍性能，较之现有技术取得更好的技术效果。