普通与轻集料砼压-剪复合受力性能试验研究

为探究普通混凝土与轻集料混凝土压-剪复合受力状态下的力学性能,以不同轴压比为加载工况对混凝土压-剪复合受力进行试验研究。通过压-剪液压伺服机得到了两种混凝土破坏形态和横向剪切荷载-位移曲线,提取横向剪切荷载-位移曲线特征值,对比分析两种混凝土复合受力的力学性能。研究结果表明,两种混凝土横向剪切峰值荷载、剪切峰值位移和残余荷载均随轴压比提高而增大,轻集料混凝土提高相对更为明显。由残余荷载分析可知,两种混凝土剪切破坏面存在稳定的摩擦系数,轻集料混凝土的摩擦系数明显高于普通混凝土。应用数学回归分析方法得到两种混凝土轴向荷载与剪切峰值荷载、轴向荷载与残余荷载均呈线性变化关系。基于八面体空间应力提出两种混凝土不同解析式的破坏准则方程,所得解析式能够很好地反映两种混凝土压-剪复合受力破坏规律,为工程应用的研究提供有利价值。

Comparative Study on Compressive-Shear Behavior of Ordinary Concrete and Lightweight Aggregate Concrete

In order to study the mechanical properties of ordinary concrete and lightweight aggregate concrete under compression-shear composite stress, the experiment of compression-shear composite stress was carried out under different axial compression ratio. The different failure modes and the shear load-displacement curve for two concrete were extracted by using compression-shear hydraulic servo machine and the characteristic values of the transverse shear load-displacement curve were extracted, which were used to be comparative analysis their mechanical properties. The results showed that with the increase of the axial compression ratio, the lateral shear load, shear peak displacement and residual load of the two kinds of concrete are all increased, and the light aggregate concrete is relatively more obvious. From the residual load analysis, there were stable friction coefficient between the shear failure surfaces and the friction coefficient of the lightweight aggregate concrete was obviously higher than that of ordinary concrete. Accor-ding to the mathematical return of two kinds of concrete, axial load and shear peak load, axial load and residual load were linear relationship. The failure criterion of the two kinds of concrete with different analytic properties were obtained by using the octahedral space stress. The analytical formula could respond to the failure law of the two concrete compression-shear composite forces well which provide favorable value for engineering application research.