泵送混凝土坍落度损失原因及对策

Slump loss of pumping concrete and the measures

对于泵送混凝土而言,其坍落度经时损失是非常重要的技术指标。文章详细分析了影响混凝土坍落度经时损失的主要原因——混凝土配合比、组成材料、生产条件和环境因素及其影响关系;在此基础上提出了控制混凝土坍落度经时损失的对应举措。实践证明,选择水灰比为0.45～0.6,砂率为38%～43%,C3A和碱的质量分数分别小于7%和1%的硅酸盐和普通硅酸盐水泥,以及选择细度模数为2.7～2.9的中砂和缓凝型减水剂,就可很好控制混凝土的坍落度经时损失。

For pumping concrete, the slump loss is a very important index. The main factors the mix proportion, raw material, production condition and environment and the relationship of affecting was analysed indetail, and on base of which the countermeasures to control the slump loss of pumping concrete were put forward. The practice proved that the slump loss could be controlled if the water to cement ratio was 0.45 -0.6, and the sand-coarse aggregate ratio was 38% -43%, C3A and alkila content of portland cement or ordinary portland cement was lower than 7% and 1% respectively, and medium sand which fineness modulus was 2.7- 2.9 and retarding and water reducing agent were selected.