A numerical algorithm for evaluating the chloride diffusion coefficient of concrete with crushed aggregates

Since the deterioration of marine reinforced concrete structures is, to a great extent, related to the movement rate of chloride ions in concrete, it is essential to determine the chloride diffusion coefficient of concrete through experiment or theoretical prediction. This paper proposes a numerical algorithm for evaluating the chloride diffusion coefficient of concrete with crushed aggregates. In the numerical algorithm, the mesostructure of three-phase concrete is reconstructed by generating polygonal aggregates of various sizes and placing them within a simulation element with periodic boundary conditions. The random walk algorithm is then applied to the simulated three-phase concrete for computing the chloride diffusion coefficient. With this algorithm, the reasonable values of the random walk radius and the number of simulations are determined. Finally, comparisons are made between the calculation results and the experimental ones obtained from the literature to verify the numerical algorithm. Based on several numerical examples, three primary factors, the aggregate content, and the thickness and chloride diffusion coefficient of interfacial transition zone, influencing the chloride diffusion coefficient of concrete, are evaluated quantitatively. This paper concludes that the proposed numerical algorithm is effective in evaluating the chloride diffusion coefficient of concrete with crushed aggregates.