盐渍土环境下钢筋混凝土腐蚀的电化学研究

Electrochemical Study on the Corrosion of Reinforced Concrete under Saline Soil Environment

摘要:

采用极化曲线、电化学阻抗谱技术对4种盐渍土环境下的钢筋混凝土试件进行了测试，考察了不同腐蚀环境及腐蚀阶段钢筋混凝土试件腐蚀特征的差异性.试验结果表明：盐渍土环境中硫酸根离子与氯离子的质量比m(SO2-4)/m(Cl-)不同，钢筋的腐蚀特征呈现明显的差异；总含盐质量分数为5%的模拟液中m(SO2-4)/m(Cl-)由0增加为0082或0275时，在腐蚀中、后期钢筋腐蚀速率较快；当m(SO2-4)/m(Cl-)为2070时，钢筋在整个腐蚀龄期内的腐蚀速率均较慢，说明盐渍土环境中硫酸根离子在一定含量范围内能促进钢筋的腐蚀.最后结合电化学测量结果对硫酸盐的作用机理进行了分析.

Abstract:

Corrosion characteristics of reinforced concrete specimens under 4 types of saline soil environment were investigated by means of polarization curves and electrochemical impedance spectroscopy(EIS) technique, and the difference of corrosion characteristics by environment and corrosion stage was analysed.The test results show that reinforced concrete at each corrosion stage presents distinct feature.When the mass ratio of sulfate ion vs chloride ion m(SO2-4)/m(Cl-) of saline soil environment is different, the corrosion status of reinforced concrete reveal some differences.Corrosion rate of reinforcing steel increases in middle and late stages as m(SO2-4)/m(Cl-) rises from 0 to 0082 or 0275 of simulated solution which contains 5% salt mass fraction.However, the corrosion rate of reinforcing steel becomes slow in the whole period when m(SO2-4)/m(Cl-) is 2070.So it can be concluded that sulfate ions in saline soil environment promote the corrosion of reinforcing steel in a certain content range. At the same time, the mechanism of sulfate ions was analysed combined with results of electrochemical measurement.