研究了表面涂敷氨基醇和羧酸胺基迁移性阻锈剂对掺加胶材总量0.5%氯化钠的C30混凝土中钢筋锈蚀的抑制效果及其在混凝土中的迁移性能,监测了涂敷迁移性阻锈剂(migrating corrosion inhibitors,MCIs)前后混凝土试件中钢筋的电化学阻抗谱、线性极化电阻和腐蚀电流,结果表明:涂敷迁移性阻锈剂7个月后钢筋混凝土试件平均腐蚀电流(0.136μA/cm2)是涂覆前平均腐蚀电流(3.766μA/cm2)的3.6%,扣除混凝土电阻随龄期增加使电流降低的影响,以空白试件为参照推算涂覆MCIs试件的腐蚀电流约为相同龄期未涂覆试件腐蚀电流的16%。在试验的8种MCIs中氨基醇阻锈能力较差,羧酸胺基及商业MCIs抑制效果较好;在混凝土保护层下30~40mm处检测到较高浓度的有机氮表明,迁移性阻锈剂通过毛细孔和微细裂缝渗透进入了混凝土内部并抵达钢筋表面,对剖开试件取出钢筋进行视觉观察、扫描电子显微镜和X射线能谱分析结果支持上述结论。同时对迁移性阻锈剂在氯盐条件下抑制钢筋锈蚀发展或使其修复的作用机理进行了探讨。
The migratory performance of surface applied amino alcohol and amine carboxylate based migrating corrosion inhibitors(MCIs) on the reinforced concrete and the inhibiting effectiveness on the steel bar beneath the cover of concrete adding 0.5% NaCl by mass of the cementious materials in mixing were investigated.The corrosion behavior of steel bar in the samples before and after painting the MCIs had been determined by electrochemical impedance spectroscopy,linear polarization resistance and corrosion currents for seven months.The results show that the reinforcements in concrete samples(No.1-No.8) after painting the MCIs for 7 months give an average corrosion rate of 0.136 μA/cm2,which is approximately 3.6% of the samples' average current before painting inhibitors(3.766 μA/cm2).Excluding the impact of enhancement of concrete resistance on the current with the extension of age,it was estimated that the average corrosion current of the painted samples with the MCIs is approximately 16% of the current of unpainted sample at the same age using the unpainted sample as a reference.Among the 8 kinds of MCIs,the inhibition performance of amine carboxylates-based inhibitors(No.3-No.7) and the commercial MCI(No.8) was superior.A higher nitrogen content in cover depths of 30-40 mm can explained the migration of inhibitors onto the rebar surface through the concrete capillary and micro-crack after painting MCIs for 7 months.The analysis showes the presence of inhibitors on the steel bar surface.In addition,the corresponding mechanism is also discussed.