高温后钢纤维机制砂混凝土力学强度试验研究

Experimental study on mechanical strength of steel fiber reinforced sand concrete after high temperature

通过对钢纤维机制砂混凝土试块进行高温试验,研究了钢纤维体积率和温度对机制砂混凝土高温后表观特征、质量损失率及力学强度的影响,探讨了钢纤维对机制砂混凝土力学性能的影响机理。结果表明:随着温度的升高,钢纤维机制砂混凝土质量损失率不断增大,温度达到800℃时钢纤维机制砂混凝土质量损失率最高达到9.6%;在400℃之前,抗压强度呈现先下降后上升的趋势,400℃后快速下降,且在800℃后其强度损失率达到91.5%;劈裂抗拉强度随温度升高逐渐下降,在相同温度下,钢纤维的掺入在不同程度上提高了机制砂混凝土的强度,且在钢纤维体积率为1%时增强效果最佳。基于试验结果进行统计分析,建立了考虑温度、钢纤维体积率共同影响的高温后机制砂混凝土抗压强度和劈裂抗拉强度的劣化模型。

Based on the high temperature test of steel fiber reinforced manufactured sand concrete,the influence of steel fiber volume ratio and temperature on the apparent characteristics,mass loss rate and mechanical strength of manufactured sand concrete after high temperature is studied,and the influence mechanism of steel fiber on mechanical properties of manufactured sand concrete is discussed.The results show that with the increase of temperature,the mass loss rate of steel fiber reinforced manufactured sand concrete increases continuously.When the temperature reaches 800 ℃,the maximum mass loss rate of steel fiber manufactured sand concrete reaches 9.6%.Before the temperature reaches 400 ℃,the compressive strength first decreases and then increases,and then decreases rapidly after 400 ℃,and the strength loss rate reaches 91.5% after 800 ℃.The splitting tensile strength increases with temperature.At the same temperature,steel fiber can improve the strength of manufactured sand concrete in different degrees,and the best reinforcement effect is obtained when the volume ratio of steel fiber is 1%.Based on the statistical analysis of the test results,a deterioration model of compressive strength and splitting tensile strength of manufactured sand concrete after high temperature considering the joint effects of temperature and steel fiber volume fraction is established.