Many researchers have defined critical chloride content as a specific value. The studies reporting critical threshold chloride content have involved the experimental measurement of the average amount of the total chloride content. The studies have tried to define the critical chloride content within the scope of their experimental concrete mix proportion at arbitrary time. However, there is no agreement on its value. The purpose of this study is to explore the combined effect of oxygen and chloride on reinforcement corrosion. In the experimental recipe, water soluble oxygen is taken into account to define the critical chloride content. Corrosion current density of reinforcement was measured by linear polarization resistance method.

Traditionally main driving force of chloride penetration in concrete have been regarded as diffusion, however, large construction such as tunnel elements and foundations for bridges can be placed on large sea water depths where the water pressure is fairly different from the pressure in the splash zone. Moreover, hydrostatic pressure increases in proportional to measured depth from the surface of water because of the increasing weight of water exerting downward force from above. In this study, new experiment method to estimate chloride penetration of concrete under water pressure is introduced. When the life length for such a concrete structure on a large sea water depth is estimated using the normally used models, the concrete test specimen

Since electrical resistivity of concrete can be measured in a more rapid and simple way than chloride diffusivity, it should be primarily regular quality control of the electrical resistivity of concrete which provides the basis for indirect of quality control of chloride diffusivity during concrete construction. This study can provide a non-destructive approach for durability design of marine concrete and it is expected that the result is subsequently used as a calibration curve for an indirect control of the chloride diffusivity based on regular measurements of the electrical resistivity during concrete construction.