Cathodic Behavior of Stainless Steel 316LN Reinforcing Bars in Simulated Concrete Pore Solutions

Abstract The high corrosion resistance of stainless steel (SS) reinforcing bars is widely recognized. However, little information is available on how much cathodic current a passive SS rebar assembly could produce to support a local anode as corrosion eventually starts. The ability of SS to perform as a cathode would have a direct impact on the corrosion rate of the anodic region. To address this issue, the cathodic behavior of type 316LN SS reinforcing bars in simulated concrete pore solutions was explored using the cyclic potentiodynamic polarization technique. The cathodic efficiency of sandblasted or as-received SS rebar was found to be much smaller than that of as-received carbon steel (CS) rebar. However, high temperature oxide scales, especially those formed at 700 °C, significantly increased the cathodic efficiency of SS. The effect of temperature and pH on cathodic efficiency of sandblasted SS rebar was secondary compared to that of the presence of oxide scales formed at high temperatures. The oxygen reduction rate on sandblasted SS increased upon addition of chloride ions in solution