Effects of environmental Water-Level changes and bidirectional electromigration rehabilitation on durability of concrete

Steel bars in concrete structures can become severely corroded in chloride salt-containing environments, which can shorten the service life of the structure. Bidirectional electromigration rehabilitation (BIEM), a novel type of durability repair technology used on reinforced-concrete (RC) structures experiencing chloride corrosion, involves applying an electric field to discharge chloride ions from concrete and simultaneously applying a rust inhibitor to the steel surface. In this study, indoor experiments were performed to analyse the migration of chloride ions and the corrosion inhibitor in RC structures in the atmosphere and water-level-fluctuating areas. An electroosmotic device enhanced the efficiency of BIEM. The BIEM was particularly effective in wet–dry areas and inside the electroosmotic device. More than 90% of the chloride ions on the steel surface were removed within 15 mm of the electroosmotic device, and the chloride ion migration rate on the steel surface was 40%–60%. Scanning electron microscopy revealed that the surface of the steel bars was smooth after BIEM treatment, with no obvious pitting or corrosion products. The service life of concrete was calculated according to the prediction method of concrete. It can be expected that the concrete enters the early warning zone after 15 years and the rust zone after 30 years.

在含氯盐的环境中，混凝土结构中的钢筋会严重腐蚀，这会缩短结构的使用寿命。双向电迁移修复（BIEM）是一种用于遭受氯离子腐蚀的钢筋混凝土（RC）结构的新型耐久性修复技术，它通过施加电场使氯离子从混凝土中排出，同时在钢材表面施加防锈剂。在这项研究中，进行了室内实验，以分析氯离子和缓蚀剂在大气和水位波动区域的钢筋混凝土结构中的迁移情况。一种电渗装置提高了双向电迁移修复的效率。双向电迁移修复在干湿交替区域以及电渗装置内部特别有效。在距离电渗装置15毫米范围内，钢材表面90%以上的氯离子被去除，钢材表面的氯离子迁移率为40% - 60%。扫描电子显微镜显示，经过双向电迁移修复处理后，钢筋表面光滑，没有明显的点蚀或腐蚀产物。根据混凝土的预测方法计算了混凝土的使用寿命。可以预计，混凝土在15年后进入预警区，30年后进入锈蚀区。