以阳离子螯合剂作为主缓凝剂与聚羧酸减水剂的复配研究

The study on the compound of polycarboxylate superplasticizer with positive ions chelating agent which regarded as main retarder

为解决夏季高温时以葡萄糖酸钠作为聚羧酸减水剂复配的主要缓凝剂时，混凝土流动性损失过快的问题。以阳离子螯合剂、有机缓凝剂、无机缓凝剂、水泥调节剂通过正交试验，确定了缓凝剂各组分的最佳用量。结果表明：与只用葡萄糖酸钠作为缓凝剂时相比，以阳离子螯合剂作为主缓凝剂时，90min混凝土坍落度保留值可提高10％～20％，压力泌水率比降低20％～30％，28d抗压强度差异不明显，且解决了当葡萄糖酸钠用量过高时混凝土容易出现的抓底、泌水问题。

In order to solve the problem of rapid damage on concrete mobility when using sodium gluconate as main retarder compounded with polycarboxylate superplasticizer under summer high temperature. The optimum dosage of every component is determined by the orthogonal test of positive ions chelating agent,organic retarder, inorganic retarder, cement conditioning agent. The result indicated that, compared with using sodium gluconate as retarder only,when using positive ions chelating agent as main retarder, 90 min concrete slumps retention value improved about 10%-20%,pressured bleeding ratio reduced by 20%-30%,28 d compressive strength had no significant difference. The sinkage and bleeding problems which are easy to occur when adding excessive sodium gluconate are also solved.