预湿珊瑚砂与减缩剂复合作用对超高性能混凝土性能影响的研究  

An investigation of the effectiveness of pre-wetted coral sand and shrinkage reducing admixture on the properties of UHPC

作　　者：杨荣辉 张国志[1,2,3] 陈飞翔 YANG Ronghui;ZHANG Guozhi;CHEN Feixiang(CCCC Second Harbor Engineering Company Ltd.,Wuhan 430040,China;Key Laboratory of Large-span Bridge Construction Technology,Wuhan 430040,China;CCCC Highway Bridge National Engineering Research Centre Co.Ltd.,Wuhan 430040,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040 [2]长大桥建设施工技术交通行业重点实验室,湖北武汉430040 [3]中交公路长大桥建设国家工程研究中心有限公司,湖北武汉430040

出　　处：《新型建筑材料》2020年第10期22-26,48,共6页New Building Materials

摘　　要：大掺量的硅灰与极低的水胶比使得超高性能混凝土(UHPC)具有较大的自收缩,导致其早期开裂敏感性较高。通过采用预湿珊瑚砂取代石英砂、外掺减缩剂(SRA)及二者复合的手段来降低UHPC的自收缩,改善其体积稳定性。试验结果表明:预湿珊瑚砂和减缩剂都能减小UHPC的自收缩,但也会降低UHPC的强度,并增大UHPC的干燥收缩,综合考虑对自收缩、干燥收缩及强度的影响,同时使用预湿珊瑚砂和减缩剂是最有效的方法,其中预湿珊瑚砂的最佳取代率为45%,减缩剂最佳掺量为1.8%,此时UHPC的强度并无显著降低,而自收缩也得到了很好的控制。High dosage silica fume and extreme low water-binder ratio lead to the large autogenous shrinkage of Ultra high performance concrete(UHPC),which means the early cracking sensitivity of UHPC is relatively high.This research aims to reduce UHPC's autogenous shrinkage and improve its volume stability by using pre-wetted coral sand to replace quartz sand or adding SRA,or using pre-wetted coral sand and SRA simultaneously.The results show that both pre-wetted coral sand and SRA can reduce the autogenous shrinkage of UHPC,but they would also reduce UHPC's strength and increase its drying shrinkage.Taking the effects on autogenous shrinkage,drying shrinkage and strength into consideration comprehensively,using pre-wetted coral sand and SRA together is the best solution to decrease UHPC's autogenous shrinkage without increasing its drying shrinkage or damaging its strength notably.Namely,the best replace rate of pre-wetted coral sand is 45%and the optimum amount of SRA is 1.8%.

关 键 词：预湿珊瑚砂 减缩剂 自收缩 干燥收缩 强度 

分 类 号：TU528.31[建筑科学—建筑技术科学]