Corrosion protection of steel in concrete

Abstract

An electric field modifier for boosting current output of a sacrificial anode for reinforced concrete to enhance its protective effect and direct the current output in a preferred direction to improve current distribution in galvanic protection of steel exposed to air. The combination comprises a sacrificial anode and an electric field modifier and an ionically conductive filler embedded in a cavity and the sacrificial anode is directly connected to the steel. The modifier comprises an element with an anode side supporting an oxidation reaction in electronic contact with a cathode side supporting a reduction reaction. The cathode of the modifier may form a cell with the sacrificial anode and is separated therefrom by the filler. The filler contains an electrolyte that connects the sacrificial anode to the cathode of the modifier. The reduction reaction on the cathode of the modifier may substantially comprise the reduction of oxygen from the air.

1 . A sacrificial anode reinforced concrete protection assembly for protecting steel in hardened reinforced concrete elements exposed to the air, the assembly comprising:
 a sacrificial anode;   a connector connected to the sacrificial anode for electronic connection of the sacrificial anode to steel in a reinforced concrete element; and   an electric field modifier;   
       wherein the sacrificial anode comprises:
 a sacrificial anode for reinforced concrete elements; 
 a metal less noble than steel; and 
 is at least in part surrounded by the electric field modifier; and 
 
       the modifier comprises an element having an anode side in electronic connection with a cathode side, and the anode side comprises an anode adapted to support an oxidation reaction, which anode faces away from the sacrificial anode; and 
       the cathode side comprises a cathode adapted to support a reduction reaction, which cathode faces the sacrificial anode; and 
       the modifier is separated from the sacrificial anode. 
     
     
         2 . An assembly according to  claim 1 , wherein the sacrificial anode has a charge capacity of at least 100 kC. 
     
     
         3 . An assembly according to  claim 2 , wherein the sacrificial anode has a charge capacity of at least 150 kC. 
     
     
         4 . A sacrificial anode reinforced concrete protection assembly for protecting steel in hardened reinforced concrete elements exposed to the air, the assembly comprising:
 a sacrificial anode;   a connector connected to the sacrificial anode for electronic connection of the sacrificial anode to steel in a reinforced concrete element; and   an electric field modifier;   wherein the sacrificial anode comprises:
 a sacrificial anode for reinforced concrete elements; 
 a metal less noble than steel; and 
 is at least in part surrounded by the electric field modifier; and 
 the modifier comprises an element having an anode side in electronic connection with a cathode side, and the anode side comprises an anode adapted to support an oxidation reaction, which anode faces away from the cathode side; and 
 the cathode side comprises a cathode adapted to support a reduction reaction; and 
   the modifier is separated from the sacrificial anode.   
     
     
         5 . An assembly according to  claim 4 , wherein the sacrificial anode has a charge capacity of at least 100 kC. 
     
     
         6 . An assembly according to  claim 5 , wherein the sacrificial anode has a charge capacity of at least 150 kC. 
     
     
         7 . A sacrificial anode reinforced concrete protection assembly for protecting steel in hardened reinforced concrete elements exposed to the air, the assembly comprising:
 a sacrificial anode;   a connector connected to the sacrificial anode for electronic connection of the sacrificial anode to steel in a reinforced concrete element; and   an electric field modifier;   wherein the sacrificial anode has a charge capacity of at least 80 kC, and comprises a metal less noble than steel;   the modifier comprises an element which has an anode side in electronic connection with a cathode side, and the anode side comprises an anode adapted to support an oxidation reaction, which anode faces away from the sacrificial anode;   the cathode side comprises a cathode adapted to support a reduction reaction, which cathode faces the sacrificial anode; and   the cathode side of the modifier and the sacrificial anode are arranged to form a cell.   
     
     
         8 . An assembly according to  claim 7 , wherein the sacrificial anode has a charge capacity of at least 100 kC. 
     
     
         9 . An assembly according to  claim 8 , wherein the sacrificial anode has a charge capacity of at least 150 kC.