In this study, in order to investigate the prevention effect for chloride attack of concrete by surface coating material and epoxy-resin coated rebar on a port road bridge located in the marine atmosphere of Naha Port, three types of long-term exposure test were carried out: 1) the concrete specimens with surface coating materials, 2) PC girders with surface coating materials, and 3) the concrete specimens with embedded epoxy-resin coated rebar. After a long time (1) 30 years, 2) 26 years, and 3) 25 to 26 years), various tests were conducted to evaluate the prevention effect and durability of each method. The results obtained by this study are as follows.
(1) For a long period of 30 years for the concrete specimens under the girder and 26 years for the test construction section of the actual PC girder of Naminoue bridge, the various coating materials maintained high salt barrier properties. As a result, the surface coating materials prevented the penetration of chloride ions into the concrete. It was confirmed that applying a suitable surface coating to concrete at a stage where a large amount of chloride ions did not penetrate was extremely effective as a countermeasure against chloride attack. In addition, it was confirmed that the expected service life (defined as “the period during which repainting is necessary”) greatly exceeds the existing knowledge (generally 10-15 years).
(2) In the results of exposure tests with two types of concrete specimens near the abutment of Naura bridge, it was confirmed that the epoxy resin did not deteriorate in a highly alkaline environment in concrete for a long period of 25 to 26 years. Here, the corrosion due to chloride ions was unable to be evaluated because a large amount of chloride did not penetrate the steel surface in this case.

Key Words: Marine environment, concrete structures, chloride attack, surface coating,epoxy-resin coated rebar