Effect of Cold Galvanizing Zinc Coating as a Cathodic Protection on Corrosion Rate and Bond Strength of Reinforced Concrete

Abstract

This study focuses on the corrosion rate of steel in reinforced concrete and its effect on the steel rebar physical properties: Rockwell hardness, Vickers hardness, tensile strength, and yield strength. It was no noticeable effect of the corrosion rate of steel rebar on the physical properties. Tafel test was carried out to analyze the effect of pH and salinity on the corrosion rate of the reinforcement steel. Corrosion rate of reinforced concrete for uncoated and cold galvanized zinc coated steel were investigated at different pH and salinity by using weight loss method. The maximum sheer stress required to pull out the steel samples from the concrete was studied at different pH and salinity solutions by bond strength test. The results showed that at low pH ranges (acidic medium), the corrosion rate of the reinforced concrete was higher than at high pH ranges (alkaline medium), i.e. the corrosion rate is inversely proportional to pH. The corrosion rate of reinforced steel is positively proportional to the salinity until a certain salinity concentration, and then inversely proportional to the salinity due to limited oxygen diffusion. It can be concluded that the corrosion rate of the embedded rebar in reinforced concrete affects its structural performance in two ways, either by reducing its cross-section area or by deteriorating the strength of bonds between the steel and concrete.