Patent ID: 7520974

Claim:
A method of cathodic protection of a concrete structure comprising: wherein a first part of the concrete structure is in contact with a medium, which contains water and is ionically conductive, and a second part of the concrete structure, continuous with the first part, is spaced from the medium and exposed to air; the concrete structure having steel reinforcement in the first part and the second part; applying to the structure a covering layer which covers at least part of at least one surface of the structure, the layer extending from the first part of the structure to the second part of the structure so as to have a portion of the layer which is generally in contact with the moisture and a portion of the layer which is generally out of contact with the moisture; inhibiting passage of oxygen from the air to the concrete covered by the layer by forming the layer from an oxygen impermeable material and by attaching the layer such that the layer is sealed relative to the concrete; inhibiting passage of moisture to the air from the concrete covered by the layer by forming the layer from a moisture impermeable material and by attaching the layer such that the layer is sealed relative to the concrete, such that the concrete in the second part of the structure covered by the layer is maintained wetted by the moisture; providing an anode in the medium; providing an electrical connection from the anode in the medium to the steel in the concrete; arranging the anode such that a current flows through the electrical connection between the anode and the steel and an ionic current flows through the medium and the concrete between the anode and the steel tending to inhibit corrosion of the steel; the anode being arranged such that no part of the anode is located under that part of the layer which is generally within the medium and no part of the anode is located under at least a portion of the layer extending from the medium which is generally out of the medium into the second part of the structure; and inhibiting corrosion in the steel in the second part of the structure lying under the layer by the anode in the medium.