Significance of the concentration of chloride in the repair of concrete highway structures using surface applied corrosion inhibitors

Advances in surface-applied corrosion inhibitors suggest that they have the potential to prevent or significantly retard corrosion of steel in reinforced concrete structures. It is thought that the effectiveness of the inhibitor depends on both the chloride concentration at the steel reinforcement and the inhibitor concentration. This paper presents the preliminary findings of a laboratory study into this assumption. Concrete specimens were ponded with chloride solutions to initiate corrosion. Inhibitor was applied to one face and the influence on corrosion activity was monitored by linear polarisation resistance measurement. The preliminary results of this continuing study showed that the surface-applied inhibitors could reduce the corrosion rate and this reduction depends on the chloride concentration. The practical implication is that there exists a chloride concentration range within which inhibitor use is most effective.