Tidal Water Effect on the Hybrid Cathodic Protection Systems for Marine Concrete Structures

This paper represents the behaviors of hybrid cathodic protection (hybrid CP) system in a reinforced concrete column specimen. Cathodic protection (CP) is widely used as a means of protecting corrosion for marine concrete structures such as harbor and offshore facilities. Specifically, hybrid CP, which is the combination both sacrificial anode cathodic protection (SACP) system and impressed current cathodic protection (ICCP) system, can be an optimum way to protect corrosion. Some complex concrete structures as well as harbor constructions are considered to be protected by both systems. Especially, it becomes more complicated to protect corrosion damage of concrete structures in the tidal and splash zones of marine environment. In case of Yellow Sea of the South Korea, the tidal zone reaches to 6 similar to 8m. On the condition that this system is well applied in the Yellow Sea, it is expected to show a good CP behavior to solve an under-protection problem, especially in tidal and splash zones. In this study, the hybrid system installed both the ICCP with Timesh anode and the SACP with zinc anode has been adopted to verify the current influence through laboratory experiment. CP potential and current have been investigated, in addition, 4-hour depolarization test has been involved to reveal the effectiveness of hybrid CP.