（1 清华大学土木工程系， 北京 100084； 2 中国寰球工程公司， 北京 100029）

［摘要］通过给定配合比混凝土的低温劈拉试验，考察混凝土不同低温作用工况下的受拉性能变化规律。结果表明，不同低温下混凝土立方体试件劈拉破坏形态相似；混凝土低温受拉强度离散性虽较大，但基本经历损伤阶段、快速增长阶段和平稳波动阶段。约-10℃时混凝土受拉强度达到极小值，相对常温降幅达5-7%；约-120℃时达到极大值，相对常温增幅达42-6%。随温度降低，混凝土拉压比减小、脆性增强。根据试验结果和已有的研究结果拟合的混凝土低温相对受拉强度计算公式可为工程实践提供参考。

［关键词］混凝土； 超低温； 受拉强度； 试验

中图分类号：TU528-1文献标识码：A文章编号：1002-848X(2016)13-0086-04

Experimental study on tensile strength of concrete exposed to cryogenic temperature

Shi Xudong1, Ju Yi1, Ma Chi1, Zheng Jianhua2, Zhang Tianshen1

（1 Department of Civil Engineering, Tsinghua University, Beijing 100084， China；2 China Huanqiu Contracting & Engineering Corp, Beijing 100029， China）

Abstract:Through the low temperature splitting test on concrete given mix proportion, the change law of concrete tensile mechanical properties was investigated with different low temperature conditions. The results show that under different low temperature conditions, splitting tensile failure patterns of concrete cube specimens are similar; although low-temperature tensile strength of concrete has large discreteness, it basically experiences damage stage, rapid growth stage and steady fluctuation stage. The tensile strength of concrete reached a minimum value at about  -10℃, and the tensile strength drops 5-7% compared with that at normal temperature; at about -120℃, the tensile strength reaches the maximum value with the increase of 42-6% compared with that at normal temperature. With the decrease of temperature, the ratio of tension and compression of concrete decreases, and the brittleness increases. According to the test results and the existing research results, the calculation formula of the relative tensile strength of concrete under low temperature can provide reference for engineering practice.

Keywords:concrete; cryogenic temperature; tensile strength; experiment

*国家自然科学基金项目（51078204），中国寰球工程公司科技研发课题（60010-1904-CA-BL-003）。

作者简介：时旭东，博士，教授，博士生导师，Email：shixd@mail.tsinghua.edu.cn。