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

Abstract 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.