Chloride Resistance of Assembled Bridge Piers Reinforced with Epoxy-Coated Steel Bars

Abstract

To reveal the influence of joint type and epoxy-coated steel bar surface damage on the durability of assembled bridge piers, this study simulated the potential damage to epoxy-coated steel bars at various stages of an actual construction process by bending, scratching, and knocking. The pier inter-segmental joint and the pier-bearing platform joint were designed to highlight the critical zones affecting the durability of sea-crossing bridge substructures. The migration of chloride ions into the concrete was accelerated by applying a constant voltage DC electric field. The electrochemical indexes of epoxy-coated steel bars and chloride ion content in concrete were measured regularly. Results show that the corrosion risk and corrosion rate of steel bars increase significantly when the damaged area ratio of epoxy coating is higher than 5%. The chloride ion transport rate at the interface of the pier-bearing platform joint is about 5 times that of the pier inter-segmental joint. The service life of the pier-bearing platform joint is only 1/2 that of the pier inter-segmental joint when epoxy-coated steel bars with the same treatment are used.

Keywords

• epoxy-coated steel bar
• accelerated corrosion test
• durability
• electrochemical test
• critical chloride ion concentration