Influence of carbonation on chloride-induced reinforcement corrosion in simulated concrete pore solutions

• We choose two different kinds of simulated concrete pore solution.
• The effect of carbonation on chloride-induced steel corrosion depends on the level of carbonation.
• The effect of carbonation on chloride-induced steel corrosion depends on the kinds of solution.
• The cement extract is more suitable to simulate the concrete pore solution.

The influence of carbonation on chloride-induced reinforcement corrosion in concrete has been studied in this work. Two different kinds of simulated concrete pore solutions, i.e. Ca(OH)2 + KOH + NaOH solution and cement extract, were applied to carry out the experiment. Different concentration of bicarbonate ions was added to simulate the different level of carbonation and the initiation of pitting corrosion was measured by the open-circuit potential and the corrosion current density obtained from the EIS curves. It has been found that in Ca(OH)2 + KOH + NaOH solution, a high HCO3- concentration enhances the stability of the passive film and the corrosion resistance of the steel specimen, while the low concentration of HCO3- ions accelerates the corrosion. However, in the cement extract, the HCO3- concentration always shortens the time-to-initiation of reinforcement corrosion.