Sacrificial anode and treatment of concrete

Abstract

A method of protecting a metal section in concrete. The method comprises the steps of providing a sacrificial anode and embedding the sacrificial anode in a porous matrix in the cavity; providing a source of DC power with positive and negative connections and electrically connecting one of the connections of the source of DC power to the metal section to be protected; electrically connecting the a sacrificial anode in series with the other connection of the source of DC power and spacing the source of DC power from the cavity and the connections to the source of DC power which comprise at least one of wires and cables; and driving an anode current density from the sacrificial anode in excess of 500 mNm 2 . An apparatus of protecting a metal section in concrete is also disclosed.

1 - 10 . (canceled) 
     
     
         11 . A method of protecting and/or passivating steel in concrete using a sacrificial anode assembly, the method comprising the steps of:
 forming a cavity in concrete comprising at least one of a cored hole, a drilled hole and a cut chase;   embedding the sacrificial anode assembly in a porous matrix in the cavity;   connecting the sacrificial anode assembly to the steel;   forming the sacrificial anode assembly as   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;   attaching a connector to the anode of the cell for electrically connecting the anode of the cell to the steel in the concrete;   electrically connecting a sacrificial anode in series with the cathode of the cell;   and permitting communication between the electrolyte in the concrete and the electrolyte in the cell.   
     
     
         12 . The method as claimed in  claim 11 , further comprising the step of forming the cathode of the cell from at least one of a metal oxide such as an oxide of manganese, iron, copper, silver and lead; and
 mixtures of a metal oxide with carbon such as a mixture of manganese dioxide and carbon.   
     
     
         13 . The method as claimed in  claim 11 , further comprising the step of connecting the cell and the sacrificial anode together so as to form a single integral unit. 
     
     
         14 . The method as claimed in  claim 11 , further comprising the step of forming the sacrificial anode from at least one of zinc, aluminum, magnesium or an alloy of one or more of these metals. 
     
     
         15 . 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, the sacrificial anode assembly comprising:
 a cell, which has an anode and a cathode and an electrolyte and the anode and the cathode being arranged so as to avoid 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 integral unit;   the cathode of the cell including an oxide material;   and the sacrificial anode assembly being assembled to permit 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.   
     
     
         16 . The assembly as claimed in  claim 15 , wherein the oxide material at the cathode of the cell comprises an oxide of at least one of manganese, iron, copper, silver, lead. 
     
     
         17 . The assembly as claimed in  claim 15 , wherein the assembly is adapted to fit into a cored or drilled hole up to 50 mm in diameter and 200 mm in depth or a cut chase up to 30 mm in width and 50 mm in depth.