各种混凝上减水剂被广泛用于配制大流动度混凝土,以满足一些特殊施工需要,收到了良好的效果。但是,人们在工程实践中发现,用减水剂(尤其是高效减水剂)配制的大流动度混凝土,在环境气温较高或运输距离较远或放置时间较长等场合,其坍落度会大幅度下降,仍然难以保证施工所需的流动性,给施工带来困难。这就是目前人们普遍关注的混凝土坍落度损失问题。 Various types of coagulation superplasticizers are widely used to formulate large-fluidity concrete to meet some special construction needs and have received good results. However, people have found in engineering practice that large-fluidity concrete formulated with water-reducing agents (especially high-range water-reducing agents) has slumps at high ambient temperatures, long-distance transport distances, or long-term exposures. It will be drastically reduced, and it is still difficult to guarantee the liquidity required for construction, which will cause difficulties in construction. This is the problem of concrete slump loss that people are currently concerned about.