适于钢管高强混凝土的缓凝保塑高效减水剂的研制

Development of High-Effective Retarder and Water-Reducer for Preparing High-Strength Concrete-Filled Steel Pipe

将聚羧酸减水剂、葡萄糖酸钠、硫酸锌等按一定比例复合。研制出一种高减水率、低引气量的钢管混凝土专用缓凝保塑高效减水剂WUT—G（I）；配制C50钢管混凝土时，其最佳掺量为0．9％～1．3％；配制C60钢管混凝土时，其最佳掺量为1．2％～1．6％。所配制的混凝土具有良好的工作性能：初始坍落度大于23cm、扩展度大于60cm，5h坍落度仍达14cm以上，不离析、不泌水．满足钢管混凝土泵送施工工艺要求。同时，混凝土含气量小于1．8％，能有效减少钢管混凝土中普遍存在的混凝土与钢管壁脱粘现象的产生。

A new type of high-effective retarder and water-reducer with low air entraining content and high water reducing rate for preparing high-strength concrete-filled steel pipe is developed by using of polycarboxylate water reducer and sodium gluconate as well as zinc sulphate. Experimental results of this admixture show that, when a certain amount of the admixture ranged from 0.9% to 1.3% by the weight of cement is added for preparing C50 concrete-filled steel pipe while 1.2% to 1.6% for C60 concrete filled steel pipe, fresh concrete has a perfect workability such as its initial slump is higher than 23 cm as well as initial flow is higher than 60 cm and its slump for 5 hours is above 14 cm, which meets the needs of requirements of concrete pumping technique. Furthermore, the fresh concrete has a low air-content （lower 1.8 %）, which could have a chance to decrease the probability of separation of the concrete and steel pipe generally existed in concrete-filled steel pipe structure.