Numerical Simulation on Diffusion Behavior of Corrosion Ion in Concrete under Fatigue

In corrosive environments, concrete structures, such as roads and tunnel inverts, are adversely affected by the combined effects of corrosion and fatigue loading.Fatigue loading accelerates the transmission of corrosion ions, resulting in a rapid degradation of structural performance.To examine the transmission law of corrosion ions under fatigue load, this study proposed an unsteady transmission model of corrosion ions in concrete.In view of the interaction between composite corrosion ions, a set of sulfate-chloride ion coupling transmission equations was established based on Fick's second law.Subsequently, fatigue load parameters were introduced into the corrosion ion diffusion coefficient function according to the concrete fatigue equation, and a corrosion ion transport model under fatigue load was established.Moreover, the influence of fatigue parameters on ion transport behavior was discussed based on parameter analysis.Results demonstrate that fatigue load can accelerate the transmission of corrosion ions, and the corrosion rate is positively related to loading frequency and stress level.However, when the stress level is less than 0.2, fatigue load has little effect on the transmission rate of corrosion ions.This study establishes a link between fatigue load and corrosion ion transport behavior and provides a method for assessing the durability of concrete in corrosive environments.