Abstract
•Zinc-Aluminium hot-dip galvanized coating improves corrosion of steel rebars.•Test panels in sheet form containing 10%, 15%, 20%, and 30% aluminum in zinc.•Mild steel rebars galvanized in 90% Zn − 10% Al and 100% Zn (100Z) baths.•Electrochemical, S.E.M, Raman spectroscopy, X-ray diffraction techniques used.
In this investigation zinc was alloyed with aluminum in order to improve the corrosion resistance of hot-dip galvanized coated steel rebars in contact with chloride-contaminated concrete. To rapidly assess the role of aluminum alloying in zinc, test panels in sheet form containing 10%, 15%, 20%, and 30% aluminum in zinc were prepared and evaluated in terms of their corrosion resistance via salt spray exposure tests. It was found that 10%Al-90%Zn (10AZ) provided the best results. Mild steel rebars were galvanized in 90%Zn-10%Al and 100%Zn (100Z) baths and their corrosion resistance performances when they were exposed to simulated concrete pore solution and embedded in mortars were examined. The10AZ-coated rebar showed superior corrosion resistance performance to the 100Z-coated rebar. Electrochemical impedance spectroscopy, DC polarization, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques were used to study the kinetics and corrosion mechanism of the coated rebars.