Performance of Mild Steel and Corrosion-Resistant Steel Rebars in Chloride-Contaminated Concrete

Abstract

Reinforced concrete (RC) infrastructure in Arabian Peninsula is subjected to harsh climatic conditions of high temperatures, humidity, and airborne chlorides and there is a high concentration of salts in seawater and soils. These factors instigate corrosion of reinforcing steel in RC infrastructure at the early stages of the service life. To overcome the durability issues of RC infrastructures, corrosion-resistant reinforcing bars are employed. In this study, a comparison of microcell and macrocell corrosion of mild steel (MS) and two types of corrosion-resistant rebar namely the high chromium (HC) and stainless steel (SS) was established. Nine concrete block samples of 20x10x350 mm were cast with top rows of reinforcements, the top row consists of MS, HC, or SS, and the bottom row contained only SS. Blocks were conditioned under 3.5% NaCl for 2 years and linear polarization resistance and macrocell currents were evaluated to compare the corrosion performance of mild and corrosion resistant steel rebars. It was observed that SS is the most corrosion-resistant steel rebar, where high chromium steel showed up to three times more corrosion resistance than mild steel under chloride attack.