1 前言工程中所用砼除必须满足强度、耐久性及经济合理性以外,还要求砼拌和料具有一定的和易性,即砼拌和料的流动性、粘聚性及保水性。便于施工浇筑时能够振捣密实。影响砼和易性的因素很多:如水泥浆用量、水泥浆稀稠、砂率及水泥品种、骨料种类、粒形和级配以及外加剂等,本文讲的砼二次拌和法具有改善砼熟料和易性的功效。砼二次拌和法又称分次投料拌和法。其具体操 1 Foreword In addition to the concrete used in the project must meet the strength, durability and economic rationality, but also requires a certain mix of concrete mixing workability, that is, concrete mixing material flow, cohesion and water retention. Easy to vibrate when construction pouring dense. Many factors affect the workability of concrete: such as the amount of cement slurry, thin thick slurry, sand and cement varieties, aggregate types, grain shape and grading and admixtures, etc., this article stresses the concrete mixing method has improved Efficacy and ease of material. Secondary concrete mixing method, also known as sub-feeding mixing method. Its specific operation