A STUDY ON FRACTURE-DAMAGE BEHAVIOR OF CONCRETE BASED ON THE MESO-SCALE MODEL

摘要

As a multiphase nonhomogeneous material, concrete is widely used in civil engineering. In this paper, a meso-scale mechanical model is proposed to study the deformation and failure process of concrete based on the nonhomogeneity of concrete at the mesoscopic level. First, concrete is taken as a type of three-component composite material composed of mortar matrix, aggregates and interfaces on the meso-scale. A random distribution scheme is used for aggregates deposition. Secondly, based on the continuum damage mechanics, a finite element meso-scale mechanics model for concrete is presented with damage softening stress-strain relationship to describe the mechanical behavior of different components of concrete. Numerical experiments for simulating 3-point bending beam and L-shape beam are accomplished, which show good agreement with the corresponding experimental results. In addition, nonhomogeneities of each component of concrete are considered by assuming the material properties in concrete conform to the Weibull distribution law. The influence of homogeneity index on nonlinear softening behaviors is studied in detail. It is concluded that the model is able to capture the entire process of damage of concrete, including the crack development associated with different loading stages.