不同低温作用下混凝土的受拉强度研究  

Study on Tensile Strength of Concrete Under Different Low Temperature

作　　者：时旭东[1] 崔一丹 韩大全 SHI Xu-dong;CUI Yi-dan;HAN Da-quan(Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学土木工程系,北京100084

出　　处：《混凝土与水泥制品》2022年第11期1-4,17,共5页China Concrete and Cement Products

基　　金：国家自然科学基金项目(51878375、51478242)。

摘　　要：通过由常温降至给定低温(-40、-80、-120、-160、-190℃)、经历低温再直接或以1℃/min匀速回至常温3种工况下的混凝土劈裂抗拉试验,研究了不同低温作用下混凝土的受拉强度及其离散性。结果表明:随着低温温度的降低,混凝土受拉强度变化率呈先增大后减小的趋势,而经历低温再直接回至常温和以1℃/min匀速回至常温时的混凝土受拉强度变化率变化较稳定;经历低温再直接回至常温和以1℃/min匀速回至常温的混凝土受拉强度变化率的差别较小,故可不考虑回至常温的方式对混凝土受拉强度的影响;与常温对照组混凝土相比,经历低温时和经历低温再回至常温时的混凝土受拉强度的离散性均变小,但其减小程度与低温以及经历低温再回至常温的方式有关。The tensile strength and its discreteness of concrete subjected to different low temperatures were discussed through splitting tensile experiment of concrete under three temperature conditions:cooling to given low temperatures(-40,-80,-120,-160,-190℃)from room temperature,and returning to room temperature directly and at a rate of 1℃/min after experiencing given low temperatures.The results show that with the decrease in the low temperature,the changing rate of tensile strength of concrete at low temperature increases firstly and then decreases,while the changing rate of tensile strength fluctuates and shows relatively stable when returning to room temperature directly or at a rate of 1℃/min from low temperatures.The difference between the changing rates of tensile strength of concrete returning to room temperature directly and at a rate of 1℃/min is small,so the influence of the way to return to room temperature from low temperatures on the tensile strength of concrete can be ignored.Compared with the room temperature control concrete,the dispersion of the tensile strength of the concrete after experiencing low temperature and returning to room temperature after low temperature is smaller,but the degree of reduction is related to the low temperature and the way of returning to room temperature after low temperature.

关 键 词：混凝土 超低温 受拉强度 温度作用 低温 

分 类 号：TU528.1[建筑科学—建筑技术科学]