An overview of predictive models of chloride penetration in concrete

Abstract

Corrosion of reinforcement has a major impact on structural performances and service life. This is especially pronounced in reinforced concrete structures exposed to the marine environment, whose degradation is accelerated by chloride penetration. Therefore, the process of chloride penetration is one of the most important parameters when designing reinforced concrete structures, predicting their service life, and planning remedial measures and maintenance. Engineering calculation models can be divided into empirical and physical models, based on different physical expressions depending on the dominant transport mechanism or their interdependent combination. Different numerical and analytical methods are used to solve them. Also, we distinguish deterministic and probabilistic approaches to modeling. The first model of predicting chloride penetration in concrete was presented by Collepardi in 1970. Since then, the model has been significantly improved and developed into sophisticated models, most of which take Fick's laws of diffusion as a starting point. Today's models often encounter limitations and unreliability in use and long-term predictions due to the lack of understanding of the combination of transport mechanisms under real exposure conditions, the time dependence of the apparent diffusion coefficient, quality long-term data and the determination of boundary conditions. This paper presents an overview of models aimed to predict the penetration of chlorides in concrete, with an emphasis on transport mechanisms by diffusion and sorption, or their combination.