预静态加载后的混凝土动态受压特性试验

进行了混凝土在应变速率分别为10-5/s、10-4/s、10-3/s的条件下,经历极限抗压强度分别为0、40%、60%、75%和85%的单调荷载作用的动态单轴压缩试验,在此基础上分析了经历不同单调加载历史和应变速率下混凝土的峰值应力、峰值应变和弹性模量的变化规律。试验结果表明,随着应变速率的提高,动态单轴抗压强度明显增加;当单调加载应力水平高于某一应力阈值时,混凝土极限抗压强度明显降低;混凝土弹性模量随着应变速率的提高而增加,随着单调加载幅值的增加表现出先增大后减小的趋势;混凝土峰值应变随着应变速率的提高而增加,随着单调加载幅值的增加而减少。

Experimental Study on Dynamic Compressive Behaviors of Concrete Due to Monotonic Loading History

Dynamic uniaxial compression experiment for concrete was carried out, in which specimens were subjected to monotonic loading of 0, 40%, 60%, 75% and 85% of ultimate compressive strength respectively, and at strain rates 10^-5, 10^-4 and 10^-3/s, respectively. The variation of the peak stress, the peak strain and the elastic modulus of concrete subjected to different loading history and at different strain rates was comparatively analyzed. Experimental results show that the dynamic uniaxial compressive strength of concrete increases obviously with the increase of strain rate and decreases obviously when loading exceeds a certain threshold; the elastic modulus of concrete is improved with the increase of strain rate, but it presents a first increased then decreased trend with the increase of monotonic loading amplitude; the peak strain increases with the increase of strain rate and decreases with the increase of monotonic loading amplitude.