基于DIC技术的高温后混凝土变形性能

Deformation Behavior of Concrete under Uniaxial Compression after High Temperature by DIC Technology

基于DIC(数字图像相关)技术,对经历20,200,400,600和800℃后的混凝土在单轴受压过程中的全场位移进行采集,分析了混凝土在不同温度下、不同受力阶段应变云图的变化特征和变形参数的变化规律.结果表明:400℃是混凝土横向应变集中区域与纵向应变压缩量最大区域匹配的临界温度;横向应力应变曲线原点至上升段0.4fcθ(fcθ为温度θ下的峰值应力)时对应的斜率Gr-H对温度的响应要比弹性模量Eθ对温度的响应更加敏感;高温损伤会导致混凝土在较低应力比下产生较大的体积压缩.

Based on DIC(digital image correlation)technology,the whole field displacement of concrete subjected to uniaxial compression after 20,200,400,600,800℃was observed.The variation characteristics of the strain nephogram and the variation law of the deformation parameters of concrete at different temperatures and different loading stages were analyzed.The results show that 400℃is the critical temperature for the matching of the transverse strain concentration region and the maximum longitudinal strain compression area of concrete.Gr-H(the slope corresponding to the origin of the transverse stress-strain curve to the rising 0.4 fcθ,fcθis peak strain under temperatureθ)is more sensitive to temperature than the elastic modulus Eθ.High temperature damage will lead to large volume compression of concrete at lower stress ratio.