INFLUENCE OF CARBONATION ON THE CORROSION PERFORMANCE OF STEEL HRB335 IN SIMULATED CONCRETE PORE SOLUTION

Electrochemical impedance spectroscopy, cyclic voltammetry and potentiodynamic polarization were used to investigate the effect of the decrease in pH values of simulated concrete pore (SCP) solutions due to carbonation on the corrosion of steel HRB335. The results indicated that the stability and corrosion inhibition of passive film on the steel surface decrease with decreasing pH value of SCP solutions. In SCP solutions with pH values of 12.5 and 11.5, the stability of passive film is in a competitive balance, the competition results from the dissolution of passive film due to the decreasing pH and the protective effect of calcium-iron containing protective layer CaFe2O4 or deposit CaCO3 formed on the steel surface. When the pH value decreased unceasingly (pH=10.5, 10.0), the stability of passive film decreased gradually, and the active uniform corrosion occurred on the steel surface.