硅粉对混凝土高温后力学性能影响的试验研究

Experimental study on the effect of silica fume on mechanical properties of concrete after high temperature

用硅粉替代部分水泥掺入混凝土中,对混凝土试块进行200~800℃的高温处理,再对冷却后的混凝土试块进行质量损失率测定、超声波检测、抗压强度试验、劈裂抗拉强度试验和微观试验,并对试验结果进行分析和拟合。结果表明:硅粉会增加混凝土的抗压强度、脆性以及高温爆裂几率,减小高温后混凝土的质量损失率,其最佳掺量为8%,在600℃时对混凝土抗压强度的增强效果最明显;利用超声波检测法可以较准确地对高温后硅粉混凝土的抗压强度及其损失率进行预估。

A part of cement is replaced by silica fume and mixed into concrete,and the concrete specimen was treated at a high temperature of 200~800℃.The quality loss rate,ultrasonic testing,compressive strength test,splitting tensile strength test and microscopic test of the cooled concrete specimen were carried out,and the test results were analyzed and fitted.Test results show that silica fume will increase the compressive strength,brittleness and bursting probability of concrete and will reduce the mass loss rate of concrete after high temperature.8%is the best content of silica fume,whose enhancement effect on the compressive strength of concrete is the most obvious at 600℃.Ultrasonic testing can accurately predict the concrete compressive strength and its loss rate after high temperature.