In this study, long term durability of marine concrete is investigated.
　This study was started in 1970 at Port and Harbour Research Institute, Ministry of Transport, Japan. Many specimens with several different factors. such as type of cement, mixing water and cover thickness of reinforcing steel in concrete, were fabricated and exposed under marine environment. During 20 years' exposure, several properties of concrete and reinforcing steel have been tested both chemically and physically. From the test results, several important conclusions were derived. In this paper, some findings from a series of tests are presented.