预制构件用自密实免蒸养混凝土试验研究

Experimental Study on Self-compacting and Non-steam Curing Concrete for Precast Concrete

为解决装配式预制构件生产中机械振捣和蒸汽养护带来的诸多问题,本课题进行了基于自密实的免蒸养混凝土配合比系统研究。研究表明:采用CECS203或CCES02设计的自密实混凝土相比采用JGJ/T283的具有较小收缩,更适宜于预制构件;采用P.Ⅱ型水泥、粉煤灰掺量15%、矿渣粉掺量20%、硫铝酸盐水泥比例5%(或促凝减缩剂掺量10%/早强剂1%)时,混凝土综合性能相对较好,可以在自密实基础上实现夏季免蒸养、其他季节缩短蒸养时间1/3以上的效果;掺加硫铝酸盐水泥、促凝减缩剂或早强剂后,混凝土氯离子渗透性能略有改善;SEM微观结构形貌分析结果与宏观性能是一致的。

In order to solve many problems caused by mechanical vibration and steam curing in the production of precast concrete,this paper has carried out a study on the mixing ratio system of non-steam curing concrete based on self-compacting. The research shows that the self-compacting concrete designed by CECS203 or CCES02 has a smaller shrinkage than that designed by JGJ/T283,which is more suitable for PC. The P. Ⅱ type cement,15% dosage of fly ash and 20% of slag powder,5% dosage of aluminate cement（or 10% dosage of coagulant shrinkage-reducing agent or 1% of early strength agent）,the comprehensive performance of concrete is relatively good,non-steam curing on summer can be realized on the basis of self-compacting,other seasons shortened steam curing time more than one third of; The permeability of chloride ion in concrete was improved slightly after adding aluminate cement,coagulant shrinkage-reducing agent or early strength agent. The results of SEM microstructure morphology analysis are consistent with the macroscopic properties.