采用微波炉加热方法建立了一套有效的混凝土高温单轴压缩试验技术,获得混凝土在温度为16~650℃时的应力应变曲线,试验结果分析表明混凝土经高温损伤后,混凝土强度下降,峰值应变增大,弹性模量减小。在此基础上,定义温度软化因子与损伤变量,以经典损伤理论模型为基础,借用混凝土微单元的强度概率分布函数,结合混凝土宏观高温力学特性,构建了一个统一方程来描述混凝土在高温时的受压损伤全过程,结果表明该混凝土本构模型与试验结果吻合较好,方程简单,物理参数含义明确,便于应用。
An effective technology about uniaxial compression test of concrete with high-temperature was established by the microwave heating.Got many stress-strain curves of the concrete whose temperature changed from 16℃to 650℃.The test results showed that the strength of concrete decreased,the peak strain increased and the elastic modulus decreased when the concrete was at high temperature.On the basis of the preceding tests results,an temperature softening factor and a damage variables were defined.At the same time,according to the mechanical behaviors of high-temperature concrete,based on classic damage theory and concrete microcell's probability distillation function of strength,a unified equation was put forward to describe the whole process of high-temperature concrete's stress-strain relations under uniaxial compression.The equation was simple,had clear physical parameters and tallied closely with the test results.So it can be used in engineering.