Influence of chloride cation type on threshold level of steel reinforcement corrosion
1.College of Mechanics and Materials, Hohai University, Nanjing, Jiangsu 210098,China; 2.State Key Laboratory of HydrologyWater Resources and Hydraulic Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Abstract：To investigate the influence of chloride cation type on the threshold level for the corrosion of steel reinforcement in concrete, saturated Ca(OH)2 solution and cement extract were used as simulated concrete pore solutions. Four chloride salts of KCl, NaCl, CaCl2 and MgCl2 were used to corrode steel reinforcement. Combined the open-circuit potential with corrosion current, the initiation of pitting corrosion was detected by electrochemical impedance spectra. The results show that the chloride cation type has marked influence on the threshold level. The threshold level in saturated Ca(OH)2 solution is decreased by Mg2+ and Ca2+ , but increased in cement extract. The threshold levels for the chloride salts with equal valent cation are the same in the two types of solution.
2012, Vol. 33 
