Abstract
Under marine environment, corrosion rates of steel materials depend on oxygen supply rate to the steel surface. Therefore, it is said that corrosion rates are mitigated if the steel surface is covered by rock-fill or seabed soil. However, the relationship between the corrosion rate and the environmental condition in front of the steel structure is still unclear and corrosion rates of steel materials which covered by rock-fill or seabed soil are not evaluated correctly. In this study, dissolved oxygen diffusion coefficient of solution or materials which exist in front of the steel material was measured by the electrochemical method to evaluate the oxygen supply rate to the steel surface. Then, the relationship between corrosion characteristics and oxygen supply rates was investigated. As the result, it was fond that the particle size and void ratio of the material which covers the steel surface control the amount of dissolved oxygen diffusion coefficient. A high correlation was found between corrosion rates and dissolved oxygen diffusion coefficient.
