Cathodic protection
Corrosion is a result of an electrochemical reaction driven by a potential difference between two locations on the surface of a metal, an anode and a cathode, which are connected by an electronic path and immersed in the same electrolyte.
The anodic site discharges current into the electrolyte, and the cathode receives current from the electrolyte.
Cathodic protection involves providing current flow onto the structure through the electrolyte sufficient to overcome the natural corrosion current discharge from the anodic sites, making the entire structure a cathode or net recipient of electric current.
The design of cathodic protection must be carried out in accordance with EN12696 by a specialist engineer, based on basic information about the structure (surface to be protected, geometry, the current degree of corrosion, degree of exposure, the resistivity of the concrete, continuity of the reinforcement, etc.) and with the cathodic protection products that best adapt to the protection requirements (maximum current intensity per anode, estimated current density depending on the degree of corrosion existing in the structure, estimated average life, the existence of electrical supply, vandalism, available budget, etc.).
Cathodic protection systems fall into two categories, impressed current and galvanic.
There are advantages and disadvantages to selecting galvanic CP or ICCP.
Selecting the right method for each application depends on the type of structure to be protected, the environment, and the needs of the owner. However, there are numerous ways for ICCP and GCP to be applied to marine structures.
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