Improved numerical model for steel reinforcement corrosion in concrete considering influences of temperature and relative humidity

- An improved numerical model for steel reinforcement corrosion in concrete was developed.
- Influences of temperature and relative humidity on process control and corrosion rate were investigated.
- Effects of forward and reverse electrode reactions on activation overpotential were considered.
- Influence of temperature on the critical relative humidity under different conditions was discussed.

An improved numerical model for steel reinforcement corrosion in concrete was developed to investigate the influences of temperature and relative humidity on process control and corrosion rate of steel reinforcement in concrete. In order to overcome the limitations of current numerical corrosion models which oversimplify the activation overpotential, the influences of both forward and reverse electrode reactions on the activation overpotential were considered based on the original formulation of the Butler-Volmer equation. Meanwhile, the influences of temperature and relative humidity on the kinetic parameters of corrosion and the properties of concrete pore solution were considered simultaneously. Moreover, the applicability and efficiency of the proposed numerical model for steel reinforcement corrosion were verified by comparing with current empirical prediction models as well as available experimental data of both artificially accelerated and natural exposure corrosion tests. Finally, the influences of temperature and relative humidity on process control and corrosion rate of steel reinforcement in concrete were investigated comprehensively. Furthermore, the influences of temperature, water-to-cement ratio, concrete cover depth, and chloride content on the critical relative humidity were also discussed.