氯盐侵蚀混凝土结构延寿技术初探Ⅰ——模拟孔隙液中6种胺类有机物阻锈性能分析

Preliminary Study on Service Life Extension of Concrete Structures under Chloride Environment

摘要:

采用动电位极化测量和电化学阻抗谱法，结合氯离子浓度、阻锈剂浓度及溶液pH值这3个影响因素，研究6种胺类有机物（三乙烯四胺、二甲胺、N,N 二甲基乙醇胺、1,6 己二胺、胍及乙醇胺）在有氯盐存在的模拟混凝土孔隙液中对钢筋锈蚀行为的影响.结果表明：随着氯离子浓度的增加，同一阻锈剂的阻锈能力下降；相同氯离子浓度下，不同的胺类阻锈剂阻锈效果不同；在pH=1250情况下，当阻锈剂浓度与氯离子浓度比值接近1时，二甲胺、1,6 己二胺、胍及三乙烯四胺的阻锈效果比较理想，而乙醇胺和N,N 二甲基乙醇胺阻锈能力较弱；当阻锈剂浓度偏低时，其没有明显的阻锈效果，甚至有可能形成阳极腐蚀而加速钢筋腐蚀；随着溶液pH值的降低，钢筋的耐蚀性能降低，同一阻锈剂的阻锈效果下降.

Abstract:

The effectiveness of six amine based inhibitors, i.e. triethylentetramine, dimethylamine, N,N dimethylethanolamine, ethanolamine, 1,6 hexanediamine,guanidine, in preventing carbon steel chloride induced corrosion in chloride contaminated simulated concrete pore solutions was investgated. Corrosion behaviors of steel in different solutions were observed by means of electrochemical potentiodynamic polarization and electrochemical impedance spectroscopy(EIS). The results show that the effectiveness of amine based inhibitors is related to the pH value of the solution, inhibitors concentrations and chloride ion concentrations. The results indicate that, the drop of pH value and the increase of chloride ion concentration would result in the decline of corrosion resistance of reinforced steel in the solution with same inhibitors concentration. At same inhibitors concentration and chloride ion concentration, different amine based inhibitors have different inhibiting effect in preventing carbon steel chloride induced corrosion. In case of pH=1250, when the concentration ratio of amine based inhibitors and Cl- is close to 1, triethylentetramine, dimethylamine, 1,6 hexanediamine and guanidine clearly delay the start of corrosion, N,N dimethylethanolamine and ethanolamine have little effect on the steel. Hence amines based inhibitors, triethylentetramine, dimethylamine, 1,6 hexanediamine and guanidine can be used as corrosion inhibitors for electrochemical injection in chloride polluted concrete.