Physicochemical modelling in chlorides migration in concrete with account of multi-species coupling, reaction kinetic and pore evolution

Chloride-induced corrosion poses a significant challenge to the long-term sustainability of concrete structures exposed to seawater. This study proposed a multi-species reactive transport model to investigate the complex interplay between ion-cement physicochemical reactions, diffusion-migration of various ionic species, and evolving pore structure during chlorides migration. The dynamic physicochemical binding process is involved in modelling by incorporating thermodynamic equilibrium reactions and non-equilibrium isotherm, respectively. The reactive model is calibrated against experimental chloride migration data, allowing for precise simulations of ionic distributions, hydrate transformations, and porosity dynamics in concrete over time. Results underscore the significance of reaction kinetics in chloride binding and transport, demonstrating that a dynamic, chemically-driven approach improves the predictive accuracy of chloride migration in concrete, and offering novel insights for designing durable and sustainable cementitious systems in chloride-rich environments.