高温处理后高强度混凝土(HSC)的力学性能研究

Study on mechanical properties of high-strength concrete subjected to high temperature treatment

模拟火灾情况下高强混凝土(HSC)经过高温处理后的力学性能,有利于分析和改善HSC的使用性能。基于混凝土损伤理论,建立高温处理后混凝土动态损伤的计算公式。对25个HSC棱柱体试件进行不同高温加热处理,并对高温处理后的试件,利用电液伺服压力试验机进行不同应变率下的轴向动态受压试验。试验结果表明,200℃以下的HSC棱柱体外观正常,400~800℃之间的HSC棱柱体开始出现裂缝,并随温度的升高裂缝不断增多,温度越高,裂缝的宽度越大,20℃时HSC棱柱体的损伤平均值为0.287,温度越高,损伤平均值越小,800℃的HSC棱柱体的损伤平均值相比20℃的减小47.4%,温度对HSC的损伤影响较大,温度越高,HSC的损伤越大。

It is beneficial to analyze and improve the service performance of high-strength concrete （HSC） to study the mechanical properties of HSC subjected to high temperature treatment under simulated fire. Based on damage theory of concrete, calculation formula of dynamic damage of concrete after high temperature was proposed. Heating treatments on 25 HSC prism specimens were conducted under different high temperatures, and axial dynamic compression tests were conducted on high temperature treated specimens with the use of electro-hydraulic servo pressure testing machine under different strain rates. The test results show that the appearance of HSC prism below 200℃ is normal, and the cracks on HSC prism begin to appear and increase at temperature between 400℃ and 800℃ with increasing temperature. The higher the temperature is, the larger the width of the crack is. The average damage value of HSC at 20℃ is 0. 287. The higher the temperature is, the smaller the average damage is. The average damage value of HSC at 800℃ is 47.4% smaller than that at 20℃. The temperature has a great influence on the damage of HSC, and the higher the damage is, the greater the damage of HSC is.