A 3D three-phase meso‑scale model for simulation of chloride diffusion in concrete based on ANSYS

•ANSYS programs were newly developed for 3D meso‑concrete with three phases.•Diameter-scaling method was proposed to ensure the distance between aggregates.•Shell elements were used to improve the modeling of interfacial transition zones.•The meso‑scale chloride diffusion was simulated by transient heat conduction.•The impacts of spatial meso‑structural parameters were parametrically analyzed. In this paper, a three-dimensional meso‑scopic concrete model based on ANSYS Parametric Design Language programs was newly proposed to simulate the chloride diffusion behavior in concrete. Taking the concrete heterogeneity in account, the concrete was considered as a three-phase composite consisting of mortar matrix, aggregates and interfacial transition zones. Spherical aggregates were randomly generated with size distribution described by the Fuller grading curve then inserted into an assumed homogeneous mortar matrix. A method named as the diameter-scaling method was proposed to ensure the minimal distance between spherical aggregate particles. Then, the finite element model based on transient heat conduction was utilized to simulate the meso‑scale chloride diffusion process in the concrete wherein the mortar was modeled by solid elements and interfacial transition zones were simulated by shell elements with constant thickness. The experimental data in literatures was applied to validate the simulated results, which illustrates that the proposed model is robust, reliable and accurate. Finally, a parametric study was conducted to investigate the impacts of three-dimensional meso‑structural parameters, including the aggregate distribution, the aggregate volume fraction, the thickness of interfacial transition zones and the diffusivity of interfacial transition zones. [Display omitted]