Abstract
This study was conducted to identify the mechanism of steel corrosion in the re-deterioration of reinforced concrete that was earlier deteriorated due to salt attack; and repaired by partially restoring the cross section. In the test, a series of specimens were arranged to simulate a part of a reinforced concrete repaired in the deck of road bridge. The depth and area of cross section to be repaired were varied in cases with and without surface coating. The specimens were then exposed in an oceanic environment. Steel was taken from the specimens at one, three, and ten years after the start of exposure to investigate the state of corrosion. As a result, it was revealed that the rate of corrosion of steel in concrete was reduced with time as long as the surface coating remained sound. It was also verified experimentally that the corrosion of reinforcement in the area plus and minus 10 mm from the interface between the base concrete and the repaired area of cross section progressed further than in other parts owing to macro-cell corrosion in the case where the partial restoration method was applied for cross section. The rate of corrosion of reinforcement near the boundary between repaired and non-repaired areas was also presented.
