不同张口位移速率下带裂缝混凝土轴拉试验研究

Axial tension tests of cracked concrete under different opening displacement rates

为了解混凝土在动荷载作用下的力学特性,对带裂缝混凝土开展了张口位移速率10^(-5)～10^(-2) s^(-1)内的轴向拉伸断裂试验,详细研究了张口位移速率对混凝土断面特征、轴向拉伸强度、断裂韧度、弹性模量及临界位移的影响。结果表明:随着张口位移速率的增加,混凝土的断面趋于光滑;混凝土的动态轴向拉伸强度、断裂韧度、弹性模量增长因子与动态张口位移速率比值的对数呈线性增长关系;混凝土临界位移保持常量,与张口位移速率无关;同时认为通过控制张口位移的加载方式,易于得到混凝土轴向拉伸P-CMOD全曲线。

In order to clarify the mechanical responses of concrete under dynamic loading,cracked concrete axial tensile fracture tests were carried out,with the opening displacement rate ranging from 10^-5-10^-2 s^-1.The influence of opening displacement rate on the section characteristics,tension strength,fracture toughness,elasticity modulus and critical displacement was studied in detail.It is indicated that the cross section characteristics of concrete change obviously with the increase of opening displacement rate.The dynamic axial tensile strength,fracture toughness and elasticity modulus of concrete increase linearly with the opening displacement rate.Yet the critical displacement keeps unchanged.In addition,it is concluded that the whole P-CMOD curve of concrete can be easily obtained by controlling the loading mode of opening displacement.