Experimental and Numerical Approaches to Carbonation–Chloride Ingress Effects on Corrosion of Reinforced Concrete: A Review

The impact of climate change on key environmental variables is well-known; yet its effect on complex phenomena such as corrosion due to carbonation and chloride ingress remains a subject of ongoing debate. While several studies have examined these processes individually, the interaction between carbonation and chloride penetration in reinforced concrete structures is less understood. Chloride ion ingress is particularly relevant in marine environments, where salt spray and carbonation may occur concurrently. Similarly, structures in urban areas exposed to de-icing salts and high CO2 levels due to traffic and pollution face increased corrosion risks. Previous research suggests that carbonation can significantly influence chloride ion transport in concrete, but its exact effect—whether it accelerates or decelerates damage—varies across studies. Some models estimate that the probability of corrosion initiation under combined carbonation and chloride ingress conditions may be nearly twice as high compared to considering these mechanisms separately. Therefore, understanding this interaction is crucial for improving durability predictions and developing effective mitigation strategies. This study reviews key experimental and modeling research addressing the combined effects of carbonation and chloride penetration in concrete structures.