水胶比和粉煤灰掺量对补偿收缩混凝土自收缩特性的影响  

Influences of Water-binder Ratio and Dosage of Fly Ash on Autogeneous Shrinkage of Shrinkage-Compensating Concrete

作　　者：苗苗[1,2] 阎培渝[1] 

机构地区：[1]清华大学土木工程系,土木工程安全与耐久教育部重点实验室,北京100084 [2]重庆大学材料科学与工程学院,重庆400045

出　　处：《硅酸盐学报》2012年第11期1607-1612,共6页Journal of The Chinese Ceramic Society

基　　金：NSFC-广东联合基金重点项目(U1134008)资助

摘　　要：通过测定基准混凝土和补偿收缩混凝土的自收缩,研究添加硫铝酸钙–氧化钙类膨胀剂的补偿收缩混凝土的自收缩特性,以及水胶比和粉煤灰掺量对于膨胀剂补偿效果的影响。结果显示:在前20h内硫铝酸钙–氧化钙类膨胀剂因为没有足够的强度约束而无法对混凝土自收缩产生补偿作用,在20～168h龄期内膨胀剂开始发挥补偿作用,自收缩减小。膨胀剂对自收缩的补偿效率受水胶比和粉煤灰掺量的影响很大,水胶比越大,膨胀剂对混凝土自收缩的补偿效率越高;粉煤灰掺量越大,膨胀剂的补偿效率越高。水胶比为0.34,粉煤灰掺量为45%时,适当掺量(6%)的膨胀剂产生的膨胀可以补偿全部的自收缩,使混凝土在30h后持续保持膨胀变形。The autogeneous shrinkage of concrete with and without calcium sulphoaluminate hydrate-calcium hydroxide expansive agent was measured, and the compensating effect of expansive agent on the autogeneous shrinkage of concrete and its compensating efficiency affected by water-binder ratio and fly ash dosage were investigated. The results show that the expansive agent does not compensate the shrinkage within 20 h due to a lack of restrict. After that the expansive agent could be used to reduce the autogeneous shrinkage of concrete. The elevated water-binder ratio and fly ash dosage could improve the compensating efficiency. The appropriate amount of the expansive agent （6%） could generate a sufficient expansion to compensate all the autogeneous shrinkage of concrete with water-binder ratio of 0.34 and fly ash content of 45%, and could keep it swelling constantly after 30h.

关 键 词：补偿收缩混凝土 粉煤灰 硫铝酸钙-氧化钙类膨胀剂 水胶比 自收缩 

分 类 号：TU528.55[建筑科学—建筑技术科学]