Abstract
Naturally exposed rusted rebar has been widely used for the production of reinforced concrete. However, rusted rebar is prone to corrosion under chloride ion (Cl−) contamination and/or at a low alkalinity of concrete. This study employed two surface modification methods, sand blasting and wire brushing, to augment the corrosion resistance of naturally exposed rusted rebar. Electrochemical tests revealed that the surface-modified rebar displayed a significant improvement of passivation in the concrete alkaline environment and anticorrosion performance in both the Cl− free and Cl−-containing simulated concrete pore solutions of different alkalinity. The enhanced performance was mainly due to the elimination of the rust layer and the direct exposure of the fresh metallic surface to the alkaline medium. Moreover, the effect of surface nanograins on the intensified passive film led to the best passivation performance of the wire-brushed rebar. The overall findings demonstrate that the two developed methods were conducive to the passivation and anticorrosion performance of the rusted rebar and thereby hold great promise for improving the service life of the reinforced concrete structures.
Highlights
Rebar corrosion is a major cause of the deterioration of reinforced concrete structures (RCS).It has been known that rebar corrosion is mainly induced by chloride ion (Cl− ) erosion and carbonization-induced reduction of the concrete alkalinity [1,2,3,4,5]
The open circuit potential (OCP) is greatly influenced by the surface state of the electrode
Of all the rebars occurred when theywith werethe immersed in the pH–11 in the pH–11. These findings demonstrate that compared as-received rebar, the simulated concrete pore solutions (SCPSs): sandall the rebars a sharp passivation decrease in OCP
Summary
Rebar corrosion is a major cause of the deterioration of reinforced concrete structures (RCS). It has been known that rebar corrosion is mainly induced by chloride ion (Cl− ) erosion and carbonization-induced reduction of the concrete alkalinity [1,2,3,4,5]. They both adversely cause the localized or general dissolution of the passive film and subsequent corrosion propagation in the rebar substrate. Extensive studies have examined the independent or collective effects of the Cl− erosion and carbonation of concrete on rebar corrosion and the related RCS durability [7,8,18]. The pre-formed rust layer further influences the rebar corrosion and RCS durability. The macro and micro surface states of the rusted rebar and surface-modified rebar as well as their passivation and corrosion behavior in the Cl− -free/Cl− -containing simulated concrete pore solutions (SCPSs) of different alkalinity were systematically studied
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