A volumetric-deviatoric split constitutive model for the discrete-particle simulation of concrete

Abstract

Discrete particle modeling (DPM) is a highly effective method for simulating concrete at the mesoscale. Each DPM model comprises three main components: (1) the method used for spatial tessellation of the sample into rigid particles or cells, (2) the framework for calculating interactions between particles in the elastic range, and (3) the development of constitutive models to describe behavior in the inelastic range. This study presents a new DPM model for the mesoscale modeling of concrete, with particular emphasis on all three key components. The spatial tessellation in the proposed model facilitates the formation of mixed fracture paths, accounting for both the mortar and the interfacial transition zone (ITZ). The elastic relationships are developed to accurately capture the effects of concrete's heterogeneous microstructure on the stress and strain fields. This capability has been validated by comparing the model’s results with those from a finite element meso-model. A new inelastic constitutive model is proposed, which decomposes the material’s behavior into deviatoric and volumetric components, based on the physics of fracture and failure within the concrete microstructure. Additionally, helpful guidelines and suggestions are provided for the initial estimation of each model variable. To validate the model's performance in the inelastic range, uniaxial compression, tensile splitting, and three-point bending samples are fabricated and tested. Comparison of the experimental results with the model’s predictions demonstrates that the model effectively captures failure mechanisms and accurately predicts stress-strain responses under various loading conditions.