间歇电流双向电渗中氯离子和阻锈剂传输和作用机理研究

Reinforced concrete (RC) structures exposed to chloride environment are prone to deterioration and premature failure which causes low durability. Mechanism study on corrosion control methods of chloride-contaminated RC structures is of great social and economical significance for the RC structures under severe corrosion environment represented by marine RC structures. The mode of intermittent current is proposed to replace the traditional continuous constant impressed current used in the bidirectional electromigration process of chloride and nano chitosan oligosaccharide sol gel corrosion inhibitor. Accurate chemical analysis, sensitive electrochemical chemical analysis and modern surface analysis such as elemental analysis, electrochemical impedance spectroscopy, polarization curve, SEM, EDS, XRD, AFM and XPS are used to analyze the transporting mechanism of chloride and the inhibitor in concrete and the action mechanism on the interface of reinforcement and concrete. The effect of the parameters--intermittent current density and power-on/off time—are studied to optimize the intermittent current mode in order to enhance the safety and long-term effectiveness of the control and protection technology. The research contributes to the extension for the research of corrosion prevention and restoration, the innovation of corrosion control theory and the development of corrosion control technology, and finally prolongs the service life of infrastructures exposed to chloride environment.

暴露于氯盐环境的钢筋混凝土结构一直存在耐久性下降和过早劣化失效的问题，从机理研究入手，探讨钢筋混凝土的腐蚀控制方法，对于以海洋工程为代表的严酷环境钢筋混凝土结构的腐蚀防护与修复，具有重要的理论价值和社会意义。本项目拟通过改变传统外加持续恒定电流的方式，采用间歇电流进行氯离子和壳寡糖类纳米水溶胶阻锈剂的双向电渗，利用元素含量分析、电化学阻抗谱、极化曲线、SEM、EDS、XRD、AFM和XPS等精确化学分析、灵敏电化学测量和先进表面测试分析等技术，研究间歇电流作用下氯离子和纳米水溶胶阻锈剂的传输机制及其在钢筋混凝土界面的反应机理，分析间歇电流对双向电渗作用的影响，进行间歇电流最优化，以提高腐蚀控制技术的安全性和长效性。本项目的研究有助于拓展钢筋混凝土腐蚀防护与修复机理研究，创新腐蚀控制理论，完善和发展腐蚀控制技术，延长氯盐环境下基础设施的服役寿命。

以海洋工程为代表的严酷环境钢筋混凝土结构的腐蚀防护与修复，从机理研究入手，探讨钢筋混凝土电渗阻锈的腐蚀控制方法，具有重要的理论价值和社会意义。本项目研究明确了氯离子和醇胺类迁移型阻锈剂在自然条件、恒定电流和间歇电流作用下的传输机理和传输规律，优化间歇电流参数，当间歇电流密度为0.2A/m2，通断电时间比为1:1，总通电时间为21d时，电渗除氯效果最优；分析讨论了间歇电流对混凝土微观组织结构和成分的影响，指出当间歇电流密度≤0.2A/m2时，对混凝土微观结构和成分影响很小；分析和讨论了醇胺类迁移型阻锈剂和壳寡糖类阻锈剂对钢筋电极的阻锈性能和修复保护作用机理，具体针对性的讨论了醇胺类化合物中-OH、-NH2有效阻锈基团、羧化度、希夫碱接枝率和分子平面/类平面构型对阻锈性能的影响。该项目的研究，为电渗阻锈技术的应用和高效阻锈剂的筛选和研究提供理论依据，这对于氯盐环境下基础设施服役寿命的延长、防腐蚀修复技术的完善和发展、腐蚀控制理论的创新具有一定的理论和社会价值。