不同膨胀剂对C70自密实混凝土早期收缩性能的影响研究

Effects of different expanders on early contractile properties of C70 self-compacting concrete

以天津117大厦巨型柱C70自密实混凝土为基准,研究目前工程中常用的几种膨胀剂对C70自密实混凝土早期收缩性能的影响。结果表明,硫铝酸盐类膨胀剂HCSA的膨胀性能最佳,显著降低了C70自密实混凝土的早期自收缩。同时,HCSA型膨胀剂对C70混凝土的适应性良好,在不同配比中都具有明显的膨胀效果,受混凝土配合比的影响较小。不掺膨胀剂时,微珠体系的C70自密实混凝土7 d收缩率明显低于超细矿粉体系,说明微珠的掺入可以在一定程度上降低混凝土的收缩。

Based on C70 self-compacting concrete of Tianjin 117 Building giant columns,with several kinds of expansion agent commonly used in current project as the research object,the effect of different expansion agent on the early age shrinkage performance of C70 self-compacting concrete was studied in this paper. The results show that,sulphoaluminate expansion agent HCSA with best performance,reduces significantly early autogenous shrinkage of C70 self-compacting concrete. At the same time,the adaptability of HCSA expansion agent is the best in C70 self-compacting concrete,there is obvious expansion performance in different concrete mix,that is impaired little by concrete mix. Without expansion agent,7 d shrinkage rate of C70 self-compacting concrete with microsphere is lower than that with ultra-fine GGBS,showing that microsphere can reduce the shrinkage of concrete to a certain extent.