混凝土界面过渡区力学性质的非均质性对混凝土强度和损伤演化的影响

采用PFC3D软件,生成了结构上含三维随机骨料、界面过渡区在力学性质上服从Weibull分布的颗粒集合体模型,研究了混凝土中界面过渡区力学参数的非均质性对混凝土宏观力学性质和损伤演化的影响。研究结果表明,界面过渡区的非均质性对混凝土的宏观力学性质产生了很大的影响,随着界面过渡区均匀性指数的增加,混凝土模型的单轴压缩强度和弹性模量均增加,且均匀性指数和单轴压缩强度、弹性模量拟合呈指数函数关系;界面过渡区的非均质性对微裂纹萌生和损伤演化产生很大影响,损伤演化大致分为初始损伤阶段、损伤稳定发展阶段、损伤破坏阶段三个阶段;随着均匀性指数的增加,损伤变量门槛值逐渐下降,两者呈指数函数关系。

Effect of Heterogeneity of Mechanical Properties of Concrete Interfacial Transition Zone on Concrete Strength and Damage Evolution

In this paper, PFC3D software was used to generate a particle assembly model with three-dimensional random aggregates and a transitional zone in the mechanical properties obeying Weibull distribution. The effects of the heterogeneity of the mechanical parameters of the interfacial transition zone on the macroscopic mechanical properties and damage evolution of concrete were studied. The results show that the heterogeneity of the interface transition zone has a great impact on the macroscopic mechanical properties of concrete. As the uniformity index of the interface transition zone increases, the uniaxial compressive strength and elastic modulus of the concrete model increase. And the uniformity index and the uniaxial compressive strength and elastic modulus fit are exponentially related. The heterogeneity of the interface transition zone has a great influence on the microcrack initiation and damage evolution. The damage evolution is roughly divided into three stages: initial damage stage, stage of damage stability development, and stage of damage damage. With the increase of the uniformity index, the threshold value of the damage variable gradually decreases, and the two are exponentially related.