不同初始静载混凝土轴向拉伸试验研究

为研究混凝土材料的动态性能,利用MTS-810NEW液压伺服试验机对尺寸为100 mm×100 mm×510 mm棱柱体混凝土材料试样进行了初始静态荷载为0~20 k N的动态轴向拉伸试验,研究了混凝土材料经历不同初始静态荷载后的动态拉伸破坏特征、应力应变关系和动态抗拉强度。结果表明:荷载值由静态过渡到动态荷载时,混凝土材料的动弹性模量发生较大变化,且随着初始静态荷载值的增加,混凝土材料动弹性模量有增大趋势;混凝土材料动态应力应变关系曲线中,峰值应力所对应的应变值与初始静态荷载值无关;随着初始静态荷载的增加,混凝土材料动态拉伸破坏断面面积逐渐增大,且粗骨料被拉断的数目随着初始静态荷载的增加而先增加,后趋于平稳;随着初始预加静态荷载值的增加,混凝土材料的动态轴向拉伸强度先增加,然后趋于稳定。

Effects of initial static loads on the tensile strength of concrete

In order to investigate the dynamic uniaxial tension behavior of concrete material,dynamic tests on its specimens with the sizes of 100 mm×100 mm×510 mm were performed under initial static axial tensile load from 0 kN to 20 kN using the MTS-810NEW hydraulic servo testing machine. The dynamic tensile failure characteristics,the stress-strain relation and the dynamic tensile strength of concrete material under different initial static loads were studied. The results show that the dynamic elastic modulus of concrete material will have a big change when the load transits from quasi static state to dynamic state,and the dynamic elastic modulus of concrete material shows an increasing tendency with the increase of initial static load. The peak strain of concrete material is unrelated to the initial static load according to the dynamic stress-strain curves. With the increase of initial static load,the dynamically fractured sectional area of concrete specimen increases gradually,the number of fractured coarse aggregates first increases and then keep constant,and the dynamic axial tensile strength of concrete material first increases gradually and then keep constant.