The corrosion-inhibitory influence of graphene oxide on steel reinforcement embedded in concrete exposed to a 3.5M NaCl solution

Abstract

Steel reinforcement corrosion significantly reduces the durability and service life of concrete structures, particularly in chloride-rich environments such as marine and coastal areas. This study aims to reduce the corrosion rate using graphene oxide (GO) as a corrosion inhibitor. Two GO dosages (0.0005 and 0.005 wt%) were evaluated for their effectiveness in mitigating corrosion in reinforced concrete exposed to a 3.5M NaCl solution. To assess the corrosion behavior of the steel reinforcement, Open Circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS), and Linear Polarization Resistance (LPR) were evaluated over one year by wetting/drying cycles. Oxygen permeability and electrical resistivity tests were also conducted to evaluate the concrete's susceptibility to corrosion. Both GO content demonstrated significant corrosion inhibition, with the 0.005 wt% dosage providing the most effective protection. This was evidenced by the lowest i_corr values recorded during the final cycle (52), larger capacitive loops, and higher impedance in EIS results, indicating enhanced corrosion resistance. Visual inspection of steel bars further confirmed these findings, showing no signs of deterioration or discoloration in GO-modified concrete compared to steel bars extracted from reference concrete. SEM-EDS analysis revealed higher carbon content on the steel surface, suggesting GO adsorption and the formation of a protective passive layer. These results suggest that GO is a promising nanomaterial for inhibiting corrosion in steel-reinforced concrete exposed to aggressive environmental conditions.