Electrochemical evaluation of epoxy-coated-rebar containing pH-responsive nanocapsules in simulated carbonated concrete pore solution

This study introduced an enhanced corrosion performance of an epoxy coated rebar (ECR) embedded with the nanocapsules containing triethanolamine (TEA) as the corrosion inhibitor. Electrochemical corrosion tests indicated a successful protection of the artificially defected area from the sample with encapsulated TEA coating, especially in the initial immersion period, indicating that there was a successful release of TEA from the embedded nanocapsules. A considerably lower surface current density of the encapsulated TEA coating also indicated that the electrochemical reactions were delayed which were further confirmed by surface micrographs that revealed a relatively less degraded artificial defect of the sample with the encapsulated TEA coating. The corrosion product analysis denoted that the inhibiting action has delayed the further oxidation of the exposed surface by having an enhanced barrier protection that helped to maintain a lower O/Fe ratio. •The triethanolamine (TEA) was encapsulated by free-radical microemulsion polymerization, then added to the epoxy coated rebar (ECR) system.•The anti-corrosion performance of ECR with artificial defect was electrochemically evaluated by using simulated carbonated pore solution.•The ECR with embedded TEA nanocapsules represented enhanced corrosion resistance, especially in the early immersion period.•The ECR with embedded TEA nanocapsules revealed less degradation of the exposed surface, evidenced by the surface oxidation level and type of main corrosion product.