普通混凝土主要由水泥、砂子、石子和水四种材料组成,现在人们在混凝土施工中又加进了另一种材料,它的掺量虽小,一般只占水泥重量的千分之几到百分之五左右(特殊情况例外),但作用却很大。它有改善混凝土拌和物和硬化后的各项性能,提高耐久性,提高强度,增加和易性,便利施工等特性。这种在混凝土拌和过程中加入的附加材料, Ordinary concrete is mainly composed of cement, sand, stone and water. At present, people add another material to the concrete construction. Although its amount is small, it usually occupies only a few thousandths to a hundredths of the weight of cement. About five out of ten (except for special cases), but the effect is great. It has the properties of improving concrete mix and hardening, improving durability, increasing strength, increasing workability, and facilitating construction. This additional material added during the concrete mixing process,