水浸泡养护对铝酸钙水泥水化行为影响的研究

摘要

为研究水浸泡养护对铝酸钙水泥水化行为的影响,以纯铝酸钙水泥Secar71为研究对象,试验温度为20 ℃,按水灰质量比0.3将水与铝酸钙水泥混合搅拌均匀,采用TG-DSC、XRD、SEM等方法对比研究了铝酸钙水泥在自然养护与水浸泡养护两种条件下分别养护1、7和15 d的水化行为.结果表明:铝酸钙水泥与水混合后,自然养护条件下,在最初的几分钟内有少量的放热,经过诱导期后有大量的放热,形成了一个"一次水化峰",之后进入稳定期;注水浸泡养护后试样内未水化水泥产生一个较"一次水化峰"低的"二次水化峰",之后水化缓慢;浸泡养护结束后试样内水化产物量与自然养护的相比明显增多,生长发育良好的片状CAH10相和絮状或粒状的三水铝石沿试样孔隙分布,填充气孔,试样结构更加致密.%In order to investigate the effect of curing by immersing in water on hydration of calcium aluminate cement,pure calcium aluminate Secar71 was chosen and the cement pastes were prepared using a water/cement mass ratio of 0.3 at 20 ℃.TG-DSC,XRD,SEM and some other methods were used to study the hy-dration of calcium aluminate cement cured naturally or immersed in water for 1,7,and 15 d,respectively.The results show that for natural curing,when the calcium aluminate cement is mixed with water,a small amount of heat is released in the first several minutes,after an induction period a large amount of heat is released which forms"the first hydration heat peak",then a stabilization period follows;for curing by immersing in wa-ter,the unhydrated cement in the specimen has"the second hydration heat peak",which is lower than"the first hydration heat peak",then the hydration slows down.The hydration products in the specimen cured by immersing in water are much more than those by natural curing.The well-developed plate-like CAH10,and flocculent or granular gibbsite interpenetrating in pores make the construction of the specimen denser.