Sacrificial anode and treatment of concrete

A method of cathodically protecting and/or passivating a metal section in concrete comprising:

• providing at least one sacrificial anode;
• providing a source of DC power with a negative connection and a positive connection;
• in a first protection step, electrically connecting one of the connections of the source of DC power to the metal section to be cathodically protected;
• and electrically connecting the sacrificial anode in series with the other connection of the source of DC power such that the voltage generated by the source of DC power is added to the galvanic voltage generated between the sacrificial anode and the metal section to produce a voltage greater than the galvanic voltage generated between the sacrificial anode and the metal section alone;
• and, in a second protection step, electrically connecting the sacrificial anode to the metal section with at least one electron conducting conductor that is not in series with the source of DC power to provide a path for electronic current to flow between the sacrificial anode and the metal section, wherein the current is generated solely by the galvanic voltage between the sacrificial anode and the metal section.

A method of protecting and/or passivating steel in concrete comprising:

• providing a sacrificial anode;
• forming a cavity in concrete comprising at least one of:
• a cored hole;
• a drilled hole;
• a cut chase;
• embedding the sacrificial anode in a porous matrix in the cavity;
• providing a source of DC power with a negative connection and a positive connection;
• electrically connecting one of the connections of the source of DC power to the steel to be cathodically protected;
• and
• electrically connecting the sacrificial anode in series with the other connection of the source of DC power such that the voltage generated by the source of DC power is added to the voltage generated between the sacrificial anode and the steel to produce a voltage greater than the galvanic voltage generated between the sacrificial anode and the steel alone;
• wherein the source of DC power is located away from the cavity and the connections to the source of DC power comprise at least one of:
• wires, cables.

A method of protecting and/or passivating steel in concrete using a sacrificial anode assembly comprising

• forming a cavity in concrete comprising at least one of:
• a cored hole;
• a drilled hole;
• a cut chase;
• embedding the sacrificial anode assembly in a porous matrix in the cavity;
• and connecting the sacrificial anode assembly to the steel;
• wherein the sacrificial anode assembly comprises
• a cell, which has an anode and a cathode arranged so as to not be in electronic contact with each other but so as to be in ionic contact with each other such that current can flow between the anode and the cathode;
• a connector attached to the anode of the cell for electrically connecting the anode of the cell to the steel in the concrete;
• and a sacrificial anode electrically connected in series with the cathode of the cell;
• and wherein the electrolyte in the concrete is not isolated from the electrolyte in the cell.

A sacrificial anode assembly specially adapted for embedment in a cavity in a reinforced concrete structure to cathodically protect and/or passivate the reinforcing steel, comprising:

• a cell, which has an anode and a cathode and an electrolyte and the anode and the cathode are arranged so as to not be in electronic contact with each other but so as to be in ionic contact with each other such that ionic current can flow through the electrolyte between the anode and the cathode;
• a connector attached to the anode of the cell for electrically connecting the anode to the metal section to be cathodically protected;
• and a sacrificial anode electrically connected with and electron conducting conductor to the cathode of the cell wherein the sacrificial anode and the cell are connected together so as to form a single unit;
• and providing an oxide material at the cathode of the cell;
• and providing a path for communication of ionic current from the cell to the environment such that ionic current can flow between the anode of the cell and the environment.