ABSTRACT
Corrosion of steel in concrete structures occurs because of depassivation by carbonation or chloride penetration (Z. Ahmad 2006). The corrosive products are expansive, and this causes cracking and deterioration of the concrete structures. So far, researches on the corrosion of steel in concrete structures have focused on the coastal structures such as bridges and harbor (Poursaee 2016a). Therefore, previous research provides insufficient data to understand corrosion behavior of submerged floating tunnels (SFT) in underwater environments. For this reason, the purpose of this study is to find out the tendency of steel corrosion and penetration of corrosion factors of the SFT. A corrosion test of rebar in concrete was designed considering the environmental characteristics of SFT. The hydraulic pressure at the water depth where the underwater tunnel is located is about 5 ~ 11 bar. To determine the tendency of steel corrosion in the SFT, the experiment was designed to create a high pressure environment in accordance with ASTM G109-07. A special device for high hydraulic pressure environment was designed. As a result of the experiment, it was found out that steel corrosion occurred in the hydraulic pressure environment of the immersion environment. Steel corrosion in SFT occurred faster in high hydraulic pressure environment, and the corrosion rate was high. However, over time, it was found that the corrosion rate decreased rapidly in the high hydraulic pressure environment. This result is analyzed as a reduction in the amount of oxygen in the pores due to rapid moisture penetration of the concrete. The results of this study can be used as basic data for the safety maintenance of reinforced concrete structures exposed to the deep sea environment.
