Protection of galvanized steel using benzotriazole as a corrosion inhibitor in simulated concrete pore solution and alkali-activated fly ash solution

Abstract

In this study, the natural passivation ability and chloride-induced subsequent increased levels of corrosion behaviour of galvanized steel in simulated concrete pore (SCP) solution and alkali-activated fly ash (AAFA) solution, with and without benzotriazole (BTA), were evaluated using corrosion potential (Ecorr), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP). In addition, scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS) were used to observe the morphologies of passive layers and corrosion products of galvanized steel. It was highlighted that the hydrogen evolution could be prevented by AAFA solution to some extent, thus providing a new insight on the inhibition of hydrogen evolution for galvanized steel in concrete. Moreover, due to the formation of a complex protective film, galvanized steel in AAFA solution exhibited significantly higher corrosion resistance to chloride attack than that exposed to SCP solution, which could be further enhanced by the addition of BTA.