The roles carbonate and bicarbonate ions play on pre-passive HRB400 rebars in simulated pore solutions of deteriorating concrete

To evaluate the corrosion behavior of HRB400 rebars during the aging process of concrete, corresponding simulated concrete pore solutions were proposed. Using electrochemical measurements and XPS analysis, the depassivation conditions, properties of the pre-passive films, and rebars corrosion rate were discussed. The effects of carbonate and bicarbonate ions, pH and chloride on the corrosion behavior of pre-passive HRB400 rebars were investigated. Results show that the influence of carbonate and bicarbonate ions on the pre-passive HRB400 rebars is reversed before and after its depassivation: before depassivation, carbonate and bicarbonate ions are detrimental to the stability of passive film, but beneficial after depassivation.