目前混凝土外加剂已被广泛地使用,它被看作是除水泥、砂、石、水以外,根据需要作为混凝土的一种成分而使用的材料。各类外加剂不仅用来改变混凝土拌合物及其在硬化以后的某些性能,从而改善混凝土的各种物理力学性能,还可配制出拥有某些特殊要求的混凝土。因此外加剂已逐渐成为混凝土组成中不可缺少的第五种材料。 At present, concrete admixtures have been widely used. It is considered as a material used as a component of concrete other than cement, sand, stone, and water. Various types of admixtures are used not only to change concrete properties and certain properties after hardening, thereby improving various physical and mechanical properties of concrete, but also to prepare concrete with certain special requirements. Therefore, the admixture has gradually become an indispensable fifth material in the concrete composition.