聚合物水泥修补砂浆开裂脱空破坏机理浅析与性能改善  

Mechanism analysis of crack and void failure of polymer cement repair mortar and performance improvement

作　　者：孔祥芝[1] 张恒[2] 韩强[2] 吴葵 KONG Xiangzhi;ZHANG Heng;HAN Qiang;WU Kui(China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Xinjiang Irtysh River Basin Development&Construction Administrative Bureau,Urumqi 830000,China)

机构地区：[1]中国水利水电科学研究院,北京100038 [2]新疆额尔齐斯河流域开发工程建设管理局,新疆乌鲁木齐830000

出　　处：《混凝土》2021年第9期109-111,122,共4页Concrete

基　　金：十三五国家重点研发计划(2017YFC0405004,2018YFC0406701);国家自然基金项目(51879286);中国水科院科研基金项目(SM0145B442017,SM0145B632017)。

摘　　要：针对聚合物水泥砂浆在混凝土修补中出现的开裂与脱空现象,通过有限元模拟分析了破坏机理,提出了相应的改善措施与材料。分析认为,修补材料在性能增长阶段开裂,原因是材料收缩变形产生的拉应力大于其极限抗拉强度;运行期修补体系在黏结面脱空,原因是环境温度周期性变化,修补材料与基础混凝土线膨胀系数的差异引起温度应力周期性作用导致界面疲劳破坏。通过原材料遴选和配合比优化开发的与基体协调型聚合物水泥修补砂浆,黏结强度2.25 MPa,自收缩为膨胀型,干缩率0.032%,线膨胀系数7.4×10^(-6)℃,与基础混凝土线膨胀系数基本一致。In view of the cracking and void phenomenon of polymer cement mortar in concrete repair,the failure mechanism is analyzed by using finite element simulation,and the corresponding improvement materials are proposed.According to the analysis,the reason for the cracking of the repair material in the performance growth stage is that the tensile stress produced by the shrinkage deformation of the material is greater than its ultimate tensile strength.The reason for the void of the repair system in the bonding surface in the operation period is that the periodic action of the temperature stress caused by the difference of the coefficient of thermal expansion between the repair material and the foundation concrete due to periodic change of the ambient temperature results in the interface fatigue failure.Through the selection of raw materials and the optimization of mix proportion,the development of polymer cement repair mortar coordinated with the matrix has a bonding strength of 2.25 MPa,a dry shrinkage of 0.032%and a thermal expansion coefficient of 7.4×10^(-6)/℃,which is basically consistent with the thermal expansion coefficient of the foundation concrete.

关 键 词：聚合物 修补砂浆 破坏机理 改善措施 

分 类 号：TU528.01[建筑科学—建筑技术科学]