Effect of aggregate characteristics on chloride diffusion in concrete based on mesoscale numerical simulation

• Published in: Construction & building materials Vol. 472; p. 140839
• Main Authors: Yang, Ce, Zhang, Jinxi, Guo, Wangda
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18.04.2025
• Subjects: Aggregate characteristics; Chloride diffusion; Concrete; Concrete durability; Mesoscale simulation; Concrete; Concrete durability; Mesoscale simulation; Chloride diffusion; Aggregate characteristics
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2025.140839

Chloride-induced corrosion is a significant factor in the deterioration of reinforced concrete structures, particularly prevalent in coastal environments and regions subject to de-icing salts. While aggregate characteristics significantly affect chloride diffusion, relevant research remains limited. This study aims to analyze, through mesoscale numerical simulations, the effects of aggregate shapes, contents, distributions, and interfacial transition zone properties on chloride diffusion, providing insights for optimizing concrete design. In this study, a mesoscale concrete model incorporating randomly generated convex polygonal aggregates was developed and rigorously validated against experimental data, demonstrating high reliability and accuracy. Building on this validated model, multiple configurations were systematically investigated to assess the impact of aggregate characteristics, including content, shape, and distribution, as well as the properties of the interfacial transition zone, on chloride diffusion. The results demonstrated that increased aggregate content substantially reduced chloride ingress, particularly in intermediate depths. This reduction was attributed to the elongation of diffusion pathways and the diminution of effective diffusion channels. Circular aggregates created more direct and permeable pathways, whereas convex polygonal aggregates formed more tortuous pathways with reduced diffusion. Compared to macroscale homogeneous models, the mesoscale approach provided more accurate simulations by considering aggregate heterogeneity. Additionally, the chloride distribution in the equivalent mesoscale concrete model is consistent. The study also found that the increased diffusion capacity of the interfacial transition zone facilitated the chloride diffusion. These findings contribute valuable insights for optimizing concrete design to enhance resistance to chloride-induced deterioration in aggressive environments. •A mesoscale numerical simulation model is developed and validated for chloride diffusion in concrete.•Aggregate shape, content, and distribution are quantitatively analyzed for their effects on chloride ingress.•The critical role of ITZ properties in facilitating the diffusion of chlorides is emphasised.•Practical strategies are proposed to optimize concrete mesostructure for enhanced chloride resistance.