混凝土中的各种材料,特别是水,作为骨料表面水加入搅拌机与作为搅拌水直接加入搅拌机是不相同的。在日本,由于用泵送法压送混凝土必需采用高流动性混凝土和由此所引起的泌水和冷接缝;因骨料资源枯竭使用山砂、海砂导 Various materials in concrete, especially water, are not the same as adding water to the surface of the aggregate as it is added to the mixer and directly as stirring water to the mixer. In Japan, high-flow concrete and the resulting bleeding and cold joints must be used to send concrete by pumping; sands and sea sands are used for the depletion of aggregate resources.