Abstract
Carbonation reduces the overall CO2 in the atmosphere but also poses a risk of corrosion to the steel reinforcement. A study into the corrosion resistance of reinforced steel subjected to carbonation in various concrete mixes. A total of thirteen concrete cubes, each with a different mix design were cast. Rebar samples were placed in the concrete cubes and the cubes were placed in a carbonation chamber for a period of 7, 14, 28 and 56 days. Samples were removed from the cubes thereafter. The corrosion rate of each sample was investigated via visual inspection, mass-loss method, and Linear Polarization Resistance measurements for a period of time. It was concluded the above tests provide misleading results for shorter duration, i.e., 7 and 14 days. No corrosion features were observed for 7 and 14 days of carbonation during visual inspection. Attention to base metal loss during mass-loss calculations emerged as a critical consideration to prevent overestimation of corrosion rates. The LPR test provided crucial corrosion parameters, including Ecorr (OCV), Icorr, βa, βc, corrosion rate, and Rp. Basalt Chryso mix was found to have the highest corrosion resistance among all the concrete mixes. Slag Mapei was found to be the worst mix as it had the lowest corrosion resistance. Identified research gaps underscored the potential of combining AC techniques such as Electrochemical Impedance Spec-troscopy (EIS) with DC methods for precise polarization resistances. Furthermore, extending the carbonation duration to 90 days is recommended for a thorough assessment of corrosion behaviour. This study provides valuable insights into enhancing concrete mix designs for improved corrosion resistance in reinforced struc-tures.