Investigation of Cathodic Protection of Reinforced Concrete in Marine Environment for the Application of Floating Offshore Wind Turbine
Résumé
Reinforced concrete (RC) floaters to support floating offshore wind turbine (FOWT) can exhibit premature
corrosion due to high chloride content in the marine environment. To address the concerns about their
deterioration in harsh marine environment, such as corrosion of reinforcements, eventually influenced by
biofouling on the material’s surface, this study has been designed to understand the interrelations between
natural seawater, biofouling, and cathodic protection for RC structures. The objective of the research study
is to quantify the effectiveness of cathodic protection using sacrificial aluminium galvanic anode in
conjugation with biofilm development. However, this paper presents a part of the long-term research study
investigating the comparative effects of galvanic anodes on passive steel in concrete, using CEM I and
CEM V cement types, in seawater. Experimental tests were conducted on RC blocks installed in the tidal
zone of Banyuls-sur-mer harbour and connected to a data logger for continuous monitoring of the
electrochemical state of steel. After three months of immersion, the exposed surface of RC blocks exhibited
biofouling, while its influence on the cathodic protection should be probed in detail. Monitoring the mixed
potential under temporal variations require careful consideration of tidal influences to ensure continued
protection of reinforced concrete. Each binder was tested with three replicate RC blocks, in which the
rebars exhibited similar trends in mixed potential and protection current density over time. The aluminium
anode delivered slightly higher currents, resulting in greater consumption in the rebars of CEM I reinforced
concrete blocks compared to those in CEM V.