Mesomechanical model for the fracture process of concrete

This paper presents a new mesomechanical model for simulating the fracture process of concrete. In this model, the heterogeneity of concrete, which is the key to the proper modelling of the fracture process of concrete, is described in two ways. First, the meso-level internal structure of concrete is explicitly modelled by treating concrete as a three-phase composite material: the matrix, the aggregate, and the matrix-to-aggregate interfaces between them. Second, within each phase, the mechanical properties are specified to follow the Weibull distribution with appropriate parameters. The constitutive law of each phase is defined on the basis of elastic damage mechanics, the finite element method is employed as the basic stress analysis tool and the maximum tensile strain criterion and the Mohr-Coulomb criterion are adopted as damage thresholds. Based on this model, a numerical simulation program named CFPA was developed and then deployed to simulate the fracture process of concrete under uniaxial and biaxial loadings. The results from numerical simulations are presented and are found to compare well with the experimental results.