Cl - 和SO 4 2- 对模拟混凝土孔隙液中钢筋腐蚀行为的影响

The corrosion characteristics of reinforced steel in simulated concrete pore solutions with different amount of chloride ion and sulfate ion were investigated by means of polarization curves and electrochemical impedance spectroscopy. The results show that the corrosion rate of re- inforced steel rose firstly and then declined with the increasing SO4 2- concentration in the solutions. The corrosion rate of the reinforced steel was the highest in a simulated sub-chloride saline soil so- lution (m(Cl - ) / m(SO4 2- )=1.5). This suggested that addition of certain amount of SO4 2- can enhance the corrosion of reinforced steel. The corrosion rate of reinforced steel decreased gradually with the proportionally increasing amount of SO4 2- and Cl - in the solutions, which may be ascribed to the for- mation of a thick salt film on the steel surface and thereby lead to the increase of diffusion resis- tance for cathode process.