Characteristic of Cathodic Current in Tidal Zone of Cathodically Protected Marine Steel Structure in the Ocean

Abstract

This paper describes results of exposure test by using the test pieces which simulate cathodically protected marine steel structure. The cathodic current density in tidal zone had maximum value according to the reduction of rust formed at the time of low water, when immediately after immersion. The cathodic current density in tidal zone decreased gradually toward high water, and increased gradually after the time of high water. The reason of change in cathodic current density is considered the periodically exposure in the different concentration region of dissolved oxygen by tide.