Deterioration assessment of concrete structures exposed to sea environment

The reinforced concrete structures exposed to sea environments suffer from corrosion of steel bars due to chloride ingress. Accurate prediction of chloride penetration is therefore important in assessing the deterioration of concrete structures. The chloride penetration into concrete is influenced by many parameters such as type of cement and mixture proportions. The existence of reinforcing bars may also influence the chloride diffusion process in concrete which has been neglected so far in the chloride diffusion analysis. The purpose of the present paper is to establish a rational method for accurate chloride diffusion analysis which is necessary for realistic assessment of deterioration for concrete structures. For rational chloride diffusion analysis, nonlinear binding isotherm which include the effects of cement types and water-cement ratio has been introduced. The effects of reinforcing bars on the chloride diffusion have been extensively studied by employing finite element analysis. The present study indicates that water-cement ratios and cement types affect greatly the chloride binding properties of concrete. The results also indicate that the chlorides are accumulated greatly in front of reinforcing bars, especially for large-size bars. The present study provides useful methods for realistic deterioration assessment of concrete structures exposed to chloride environments.