Corrosion Performance of Epoxy-Coated Reinforcement-Macrocell Tests

A macrocell corrosion experimental program was conducted to study the performance of bent epoxycoated bars. The damage to the epoxy coating was varied from no visible to the unaided eye (small pinholes) to large gaps of 6x6 mm. The coated bars were embedded in concrete prisms and linked electrically to uncoated bars to set up macro-corrosion cells. Concrete was contaminated with chlorides by ponding salt water in a cyclic wet and dry regime. Corrosion currents flowing from coated steel to uncoated steel were monitored over a period of 4.5 years. The corrosion rate of coated bars was determined and compared to that of uncoated bars. Forensic examinations were conducted at 1, 2, and 4.5 years to relate corrosion measurements to actual bar condition. Based on the findings, recommendations are provided for modifying current specification limits on acceptable damage to coating and improving bar fabrication and coating repair procedures.