Multi-scale peridynamic formulations for chloride diffusion in concrete

Abstract

A multi-scale peridynamic (PD) model of concrete with three material phases is developed to study the influences of the properties of the interfacial transition zone (ITZ) on chloride diffusion. In the PD model, the quadtree algorithm is employed to generate the multi-scale grid and two correction schemes based on the background grid are developed to calibrate the volume and length of PD bonds. A comparison with the uniform grid PD model and the finite element model is carried out to validate the proposed multi-scale PD model. The results of the multi-scale PD model are consistent with that of the two models. In addition, the effects of ITZ properties, including ITZ diffusivity and ITZ thickness, on chloride diffusion are investigated. These results demonstrate that the penetration depth and the chloride concentration increase with the increasing ITZ diffusivity and ITZ thickness, and the increase rate of chloride concentration decreases with the exposed time.