Corrosion protection of steel in concrete

A sacrificial anode assembly comprising:

• an attachment side for direct attachment to a section of steel,
• a sacrificial anode being a metal less noble than steel;
• an electric field modifier;
• and
• a connector for electronic connection of the sacrificial anode to steel in a reinforced concrete element;
• wherein the sacrificial anode is at least in part surrounded by the electric field modifier, and
• the electric field modifier comprises an element with a first side that is a modifier anode which supports an oxidation reaction in electrical contact with a second side that is a modifier cathode which supports a reduction reaction;
• the modifier cathode faces the sacrificial anode and is separated from the sacrificial anode;
• the modifier anode faces away from the sacrificial anode;
• and
• the electric field modifier is positioned, relative to the sacrificial anode, to enhance a flow of current in a direction away from the attachment side.

A sacrificial anode assembly comprising:

• a sacrificial anode being a metal less noble than steel;
• a connector for electronically connecting the sacrificial anode to steel in a reinforced concrete element;
• and
• an electric field modifier substantially surrounding the sacrificial anode;
• wherein the assembly protects steel in a hardened reinforced concrete element exposed to air;
• the electric field modifier comprises an element with a first side that is a modifier anode which supports an oxidation reaction in electrical contact with a second side that is a modifier cathode which supports a reduction reaction;
• the reduction reaction on the modifier cathode substantially comprises the reduction of oxygen from the air;
• the modifier cathode faces the sacrificial anode and is separated from the sacrificial anode;
• and
• the modifier anode faces away from the sacrificial anode.

A method of protecting steel in a hardened reinforced concrete element exposed to air with a sacrificial anode assembly, the sacrificial anode assembly comprising a sacrificial anode, an activating agent and an electric field modifier;

• the sacrificial anode is a metal less noble than steel;
• the sacrificial anode is substantially surrounded by the electric field modifier;
• the electric field modifier comprises an element with a first side which comprises a modifier anode which supports an oxidation reaction in electrical contact with a second side that is a modifier cathode which supports a reduction reaction;
• the modifier cathode faces the sacrificial anode and is separated from the sacrificial anode;
• the modifier anode faces away from the sacrificial anode;
• and a useful life of the sacrificial anode is substantially greater than a useful life of the electric field modifier;
• and the method comprising the steps of:
• forming at least one cavity in a concrete element;
• embedding the sacrificial anode assembly within the at least one cavity;
• connecting the sacrificial anode to the steel to be protected;
• activating the sacrificial anode assembly to protect the steel in the concrete element;
• and
• once the useful life of the electric field modifier ends, the assembly providing a path for ionic conduction between the sacrificial anode and the concrete element.

A method of protecting steel in a hardened reinforced concrete element exposed to air with a sacrificial anode assembly, the sacrificial anode assembly comprising a sacrificial anode, an activating agent, an electric field modifier, the sacrificial anode is a metal less noble than steel;

• the sacrificial anode is substantially surrounded by the electric field modifier;
• the electric field modifier comprises an element with a first side that is a modifier anode which supports an oxidation reaction in electrical contact with a second side that is a modifier cathode which supports a reduction reaction;
• the reduction reaction on the modifier cathode substantially comprises the reduction of oxygen from the air;
• the modifier cathode faces the sacrificial anode and is separated from the sacrificial anode;
• and the modifier anode faces away from the sacrificial anode;
• and the method comprising the steps of:
• connecting the sacrificial anode to the modifier cathode with an electrolyte;
• forming at least one cavity in a concrete element;
• embedding the sacrificial anode assembly within the at least one cavity;
• connecting the sacrificial anode to the steel to be protected;
• and
• activating the sacrificial anode assembly to protect the steel in the concrete element.