US 6,165,346 AGranted

Cathodic protection of concrete

OwnerDavid Whitmoreinventor

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Abstract

An existing concrete structure is restored by embedding sacrificial anodes into the concrete layer at spaced positions over the layer and connecting the anodes to the reinforcing members to provide a cathodic protection against corrosion. Each anode is inserted into a drilled hole in the layer of sufficient depth to expose the reinforcement. A steel pin passes through a bore in the cylindrical anode and is attached to the reinforcement by arc welding or by impact so as to hold the anode rigidly within the hole. The hole is filled by a settable filler material. In order to maintain effective current conduction from the anode to the reinforcement through the filler over an extended period to maintain the required protection, there is added a material to hold the pH in a preferred range of the order of 12 to 14 and a deliquescent material to absorb moisture into the filler.

Claims23

Dependent claims

A method for cathodic protection of a concrete structure comprising:

providing a concrete structure having a layer of concrete and a steel member in contact with the layer of concrete;
providing a sacrificial anode member;
burying the anode member within the layer so as to be in contact with the concrete layer;
the sacrificial anode member as provided and prior to being buried in the concrete layer comprising an anode body of an anode material which is covered on at least one surface thereof by a coating material which is carried by the anode body;
the anode member being arranged such that, when the anode member is buried, the coating material is in contact with the concrete layer;
the coating material being arranged to allow communication of current through the coating material and the concrete layer between the anode body and the steel member so as to provide cathodic protection for the steel member by an electrical potential between the anode body and the steel member which causes a current to flow through the concrete layer tending to inhibit corrosion of the steel member;
the coating material comprising a solid material with a binder attaching the coating material to the anode body;
providing in the coating material an additive different from the coating material itself which additive is a deliquescent material which is bound into the coating materials;
causing the presence of the deliquescent material bound into the coating material to absorb sufficient moisture into the coating material to maintain conductivity around the anode body;
and causing the presence of the deliquescent material to keep the interface between the anode body and the coating material electrochemically active to ensure that sufficient current is maintained between the anode body and the steel member during the life of the anode body to maintain said cathodic protection.

7 more elements

A method for cathodic protection of a concrete structure comprising:

providing an existing concrete structure having a steel reinforcing member and a layer of concrete covering the reinforcing member so as to define a surface of the concrete layer spaced from the reinforcing member;
providing a sacrificial anode body formed of an anode material;
drilling a hole in the layer of the existing concrete structure so as to expose a reinforcing member therein;
inserting the anode body into the hole, the anode body being shaped for insertion into the drilled hole;
attaching the anode body to the reinforcing member;
filling the hole with a filler material;
the anode body being arranged such that, when the anode body is buried, the filler material is in contact with the concrete layer;
the filler material being arranged to allow communication of current through the filler material and the concrete layer between the anode body and the reinforcing member so as to provide cathodic protection for the steel reinforcing member by an electrical potential between the anode body and the steel reinforcing member, which generates a current tending to inhibit corrosion of the steel reinforcing member while causing the sacrificial anode to be consumed;
providing in the filler material an additive which is a deliquescent material which is bound into the filler material;
causing the presence of the deliquescent material bound into the filler material to absorb sufficient moisture into the filler material to maintain conductivity around the anode body;
and causing the presence of the deliquescent material to keep the interface between the anode body and the filler material electrochemically active to ensure that sufficient current is maintained between the anode body and the steel reinforcing member during the life of the anode body to maintain said cathodic protection.

8 more elements

Dependencies are inferred from the claim text.