Abstract: The advancement of contemporary concrete technology allows for the effective delaying of the corrosion development of steel bars, even in cases where the concentration of Cl^- in the concrete surrounding them reaches a critical level. The total of the steel bar corrosion induction stage (t₀) and the corrosion development stage (t₁) is the whole life T of reinforced concrete structures in marine conditions. Model predictions were made for t₀ and t₁ respectively. At the t₀ stage, a multi-factor concrete Cl^- diffusion model was established based on Fick's second law, taking into account the effects of concrete on Cl^- binding, Cl^- diffusion time dependence, material defects, deterioration, and other factors on Cl^- diffusion. The inverse function for the model was rigorously derived to determine how long it would take for the protective layer thickness to reach the critical Cl^- concentration at which the steel bars started to corrode. The radial critical rust expansion stress needed for the annular cylinder made of steel bars and protective layer to reach its ultimate tensile stress due to rust expansion was calculated at stage t₁ based on elasticity and fracture mechanics, taking into account the buffering effect of the interface gap layer between steel bars and concrete on initial rust expansion. The amount of time needed to produce this rust expansion stress was predicted using Faraday's equation.