Corrosion Resistance of Cr-bearing Rebar in Macrocell Corrosion Environments Due to Different Concentrations of Chloride Ions

Reinforced concrete specimens were prepared by embedding 10 types of Cr-bearing reinforcing bars having different Cr contents and supplying saltwater from the upper surfaces to allow chloride ions to penetrate into concrete, thereby forming macrocells, with the aim of developing Cr-bearing rebars having corrosion-preventing properties required under macrocell-corrosion conditions due to differences in the chloride concentrations. The time-related changes in the macrocell corrosion current density, soluble chloride ion content of concrete, and half-cell potential were then measured during corrosion-accelerating test up to eight months. Also, the corrosion area and corrosion loss of anodic and cathodic bars were measured at the end of the 8-month corrosion-accelerating test to investigate the corrosion-inhibiting property of Cr-bearing rebars in macrocell corrosion environments due to chloride ion concentration in concrete.As a result, the Cr content required for corrosion inhibition was found to be more than 7% in macrocell corrosion environments with a difference in soluble chloride ion concentrations of not more than 2.4 kg/m3.