可泵性评价与低气压混凝土的可泵性

Evaluation of pumpability and pumpability of low pressure concrete

研究掺加减水剂、引气剂、缓凝组分和生物胶,利用泵送阻力仪,分析常规混凝土可泵性测试方法的可靠性,同时对比了常压和低压下混凝土的可泵性情况,结果表明:坍落度和扩展度大、倒坍时间短的混凝土,平均泵送压力不一定小,引气气泡是一种有效的降低平均泵压的方法。高海拔条件下,大气压降低,引气剂的作用效果变差,混凝土含气量大幅降低,可泵性恶化。适当的引气气泡含量是改善混凝土可泵性的必须措施,同时要考虑到引气剂在低气压下的引气作用效果。

By adding superplasticizer, air entraining agents, retarding composition and biological glue, using pumping resistance tester, analyze the reliability of conventional concrete pump test methods and compare the concrete pump ability between the atmospheric pres- sure and low pressure. Results show that larger slump and divergence, with shorter collapsed time of concrete, does not necessarily mean smaller pumping pressure, while air bubbles are an effective method of reducing the average pump pressure. High altitude, atmospheric pressure decreases, the effect of air - entraining agents deteriorate significantly reduce air content of concrete can be a sharp deterioration of the pumpability. In low pressure area, appropriate air bubbles content can improve pumpability of concrete, while the air - entraining agent entraining effects at low pressure must be taken into account.