A Cellular Automata-Based Model for Simulating the Chloride Ion Diffusion Process of Concrete with Admixtures

To accurately simulate the chloride ion diffusion process in concrete containing mineral admixtures under coupled multi-factor effects, a cellular automata (CA)-based numerical model is developed to predict the chloride ion concentration at different depths and exposure times. The proposed model incorporates the influences of spatiotemporal variability, stress state, and admixture replacement ratio into the evolution rules of chloride transport. Accordingly, the time-dependent chloride diffusion coefficient is modified to account for the effects of fly ash and slag, enabling a more realistic representation of chloride transport behavior in admixture-modified concrete. Long-term field exposure test data reported in the literature are adopted to validate the proposed model. The simulated chloride concentration profiles at various depths and exposure durations show good agreement with experimental measurements, particularly at medium-to-long exposure ages. The results demonstrate that the CA model provides a reasonable and effective way for simulating chloride ion ingress in concrete with mineral admixtures. Furthermore, under comparable strength conditions, an increase in slag replacement ratio leads to enhanced resistance against chloride ion ingress, highlighting the significant role of mineral admixtures in improving the durability performance of concrete structures.