Finite Element Modeling of Concrete Failure Considering Structural Features

This study presents a three-dimensional random aggregate model of concrete based on meso-mechanics and applies a plastic-damage constitutive model to simulate the mechanical behavior, including crack development and patterns, of concrete under uniaxial compression and tensile loading. By varying parameters, the influence of multi-phase characteristics of concrete—such as the volume fraction of coarse aggregate and the properties of the interfacial transition zone (ITZ) between aggregate and mortar—on the stress-strain relationship was investigated. Numerical results indicate that the volume fraction of coarse aggregate has a negligible effect on the splitting tensile strength of concrete but significantly enhances its compressive strength, showing a positive correlation; the properties of the interfacial transition zone (ITZ) are a critical parameter governing the macroscopic response of concrete. The study found that as the thickness of the ITZ increases, the compressive strength of concrete improves, though the enhancement is not pronounced; all simulation results show good agreement with experimental compressive stress-strain curves. Considering computational time and modeling costs, the interfacial transition zone with a thickness of 0.3 (ITZ) is shown to be more suitable.