The apparent diffusion coefficient of chloride ion in concrete Dap is an essential parameter for the performance based design of reinforced concrete structures in which chloride induced deterioration occurs. In this study, data of Dap were gathered from both concrete specimens and existing port concrete structures, the types of which are open-typewharf, quay wall, and breakwater. The effects on Dap were investigated for some factors. The conclusions are as follows:
1) Dap in port reinforced concrete structures varied widely.
2) Obtained Dap from both concrete specimens and existing port concrete structure had a good correlation with pore volume in concrete, which was simply measured by weight measurement at the saturated and dried condition of concrete. Therefore, Dap can be estimated by this simple method.