Port concrete structures may suffer chloride attack (rebar corrosion) due to chloride ions supplied from seawater. In the case of existing structures, a surface coating material may be applied for the purpose of preventing the progress of this deterioration. However, there are few cases in which it was investigated that the effect of this surface covering material was maintained for a long period of time. Based on the above, for the purpose of grasping the performance of the surface coating material (mainly organic materials such as epoxy resin) applied to the existing pier superstructure (made of reinforced concrete) for long period, various surveys (adhesion strength, salt-shielding properties, etc.) were conducted to the surface coating materials (epoxy resin-based, which can be cured in a moist environment) that had been applied to the existing pier superstructure (made of reinforced concrete) and had passed 18 years.
In addition, in this pier superstructure, various survey (visual inspection, chloride ion concentration in concrete, etc.) was conducted to evaluate the soundness of the structural members before applying the coating material. With reference to the survey results before this application and the survey results this time, we calculated various conditions in which the surface coating material can be effective. The main findings obtained from this study are shown below.
1) It was confirmed that the epoxy resin-based coating applied to the target pier superstructure (made of reinforced concrete) maintained its performance (salt-shielding property, etc.) for a long period of about 18 years.
2) Based on the survey results obtained from the actual structure (including the survey results before applying the covering material) and the existing prediction method, the conditions under which the application of the coating material can be effective are summarized.