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 mNm2. An apparatus of protecting a metal section in concrete is also disclosed.

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 mA/m2. An apparatus of protecting a metal section in concrete is also disclosed.

Abstract: A method of using and a steel reinforced concrete protector in an anode cavity which comprises a cored hole, a drilled hole or a cut chase formed in concrete. The protector comprises a sacrificial anode assembly and a separate backfill. The sacrificial anode assembly comprises a sacrificial metal element that is a metal less noble than steel and an activator to maintain an activity of the sacrificial metal element. The at least one spacer prevents the sacrificial metal element and the activator from contacting the surface of the anode cavity. The spacer and the sacrificial metal element have a coupling mechanism which facilitates connection of the sacrificial metal element to the spacer. The backfill is a pliable and viscous material which contains an electrolyte, and the backfill facilitates embedding the anode assembly in the anode cavity. The invention also relates to a prepackaged sacrificial anode assembly and a method of increasing a shelf life of the sacrificial anode.

Abstract: A steel reinforced concrete protector in an anode cavity such as a cored hole, drilled hole or cut chase is disclosed. The protector includes a sacrificial anode assembly and a separate backfill. The sacrificial anode assembly includes a sacrificial metal element and an activator to maintain an activity of the sacrificial metal element and at least one spacer. The spacer prevents the sacrificial metal element and the activator from contacting the surface of the anode cavity. The spacer and the sacrificial metal element have a coupling mechanism which facilitates connection of the sacrificial metal element to the spacer. The backfill is a pliable and viscous material which contains an electrolyte and fills the spaces between the sacrificial anode assembly and the anode cavity wall. The invention also relates to a pre-packaged sacrificial anode assembly to increase the shelf life of the assembly.

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.

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 mA/m2. An apparatus of protecting a metal section in concrete is also disclosed.

Abstract: An electric field modifier for boosting a current output of a sacrificial anode to enhance its protective effect and direct the current output to improve current distribution in galvanic protection of steel in a concrete element exposed to air is disclosed. A cavity is formed in a concrete element and a combination comprising a sacrificial anode, an electric field modifier and an ionically conductive filler are embedded therein. The sacrificial anode is connected to the steel. The modifier comprises an element with an anode side, supporting an oxidation reaction, in electrical contact with a cathode side, supporting a reduction reaction. The cathode of the modifier faces the sacrificial anode and is separated therefrom by a filler which contains an electrolyte that connects the sacrificial anode to the cathode of the modifier. The anode of the modifier faces away from the sacrificial anode. Preferably, the reduction reaction, on the cathode of the modifier, comprises reduction of oxygen from the air.

Abstract: A method of protecting steel in concrete is disclosed. A voltage between two connections of a power supply is generated such that current can flow between a negative connection and a positive connection. In a first protection step, one of the connections of the power supply is electrically connected to the steel to be cathodically protected and a sacrificial anode is electrically connected in series with the other connection of the power supply such that the voltage generated by the power supply is added to the voltage generated between the sacrificial anode and the steel to produce a voltage greater than the voltage generated between the sacrificial anode and the steel alone. The power supply may be a cell or battery and may be combined with the sacrificial anode to form a single unit.

Abstract: A method and a steel reinforced concrete protector in an anode cavity which comprises a cored or drilled hole or a cut chase formed in concrete. The protector comprises a sacrificial anode assembly and a separate backfill. The sacrificial anode assembly comprises a sacrificial metal element less noble than steel and an activator to maintain an activity of the sacrificial metal element. The at least one spacer prevents the sacrificial metal element and the activator from contacting the anode cavity. The spacer and the sacrificial metal element have a coupling mechanism which facilitates connection of the sacrificial metal element to the spacer. The backfill is a pliable and viscous material which contains an electrolyte, and the backfill facilitates embedding the anode assembly in the anode cavity. A prepackaged sacrificial anode assembly and a method of increasing a shelf life of the sacrificial anode is also covered.

Abstract: The installation and use of embedded sacrificial anodes to protect reinforced concrete may be improved. In one example a cavity [2] is formed in the concrete [3] and a puttylike backfill [4] is placed in the cavity and a compact discrete anode comprising a sacrificial metal element [1] is inserted into the backfill and a space is provided into which the backfill may move when subjected to a pressure arising from the formation of voluminous sacrificial metal corrosion products and a high current is passed from the anode to the steel in the concrete to arrest steel corrosion and activate the anode in the backfill. The space may be provided by venting the backfill to space outside the cavity through an opening [5] or by including a void space within the backfill [6] or a void space within the cavity [7].

Abstract: The connections to anodes used in impressed current electrochemical treatments of steel in concrete construction are at risk from rapid corrosion arising from induced anodic dissolution when these connections are embedded in reinforced concrete. A corrosion resistant connection that does not require any further protective insulation can be formed using titanium conductors [2,6] and connecting the conductors together at a conductor-conductor connection [5] using a clamping device comprising a non-metallic material wherein the clamping device only brings corrosion resistant material into contact with the conductors.

Abstract: Sacrificial anode assemblies have the advantage that they can provide galvanic protection to steel in concrete and do not require long term maintenance of a DC power supply. However sacrificial anode assemblies often loose adhesion to the concrete surface. This invention discloses the use of a sacrificial anode (4) and a backfill (3) and a tape (5) and an adhesive to protect steel (8) in concrete. The backfill is preferably placed in a shallow cavity (1) in the concrete surface (2) and the sacrificial anode is inserted into the backfill. The cavity is covered with a tape that extends over the adjacent concrete surfaces on opposite sides of the sacrificial anode and backfill and the tape is attached to the concrete surface with the adhesive. The tape and the adhesive holds the anode in place and prevents a weathering environment from damaging the backfill.

Abstract: An electric field modifier for boosting a current output of a sacrificial anode to enhance its protective effect and direct the current output to improve current distribution in galvanic protection of steel in a concrete element exposed to air is disclosed. A cavity is formed in a concrete element and a combination comprising a sacrificial anode, an electric field modifier and an ionically conductive filler are embedded therein. The sacrificial anode is connected to the steel. The modifier comprises an element with an anode side, supporting an oxidation reaction, in electrical contact with a cathode side, supporting a reduction reaction. The cathode of the modifier faces the sacrificial anode and is separated therefrom by a filler which contains an electrolyte that connects the sacrificial anode to the cathode of the modifier. The anode of the modifier faces away from the sacrificial anode. Preferably, the reduction reaction, on the cathode of the modifier, comprises reduction of oxygen from the air.

Abstract: A method of protecting steel in concrete is disclosed. A voltage between two connections of a power supply is generated such that current can flow between a negative connection and a positive connection. In a first protection step, one of the connections of the power supply is electrically connected to the steel to be cathodically protected and a sacrificial anode is electrically connected in series with the other connection of the power supply such that the voltage generated by the power supply is added to the voltage generated between the sacrificial anode and the steel to produce a voltage greater than the voltage generated between the sacrificial anode and the steel alone. The power supply may be a cell or battery and may be combined with the sacrificial anode to form a single unit.

Abstract: High performance proprietary cementitious concretes or mortars developed for use as patch repair materials for corrosion damaged concrete often have high resistivities that inhibit the performance of sacrificial anodes located within the patch repair areas. A method of repair is disclosed which comprises removing the corrosion damaged concrete to form a cavity to receive a concrete repair material and forming within this cavity a smaller distinct cavity for assembling a sacrificial anode assembly and placing within this second cavity a pliable viscous ionically conductive backfill and a sacrificial anode and an activating agent to form a sacrificial anode assembly and connecting the anode to the steel and covering the anode and the backfill in the second cavity with a repair material to restore the profile of the concrete structure. In this arrangement a high resistivity repair material promotes the flow of protection current to steel in adjacent contaminated concrete that is at risk of corrosion.

Abstract: High performance proprietary cementitious concretes or mortars developed for use as patch repair materials for corrosion damaged concrete often have high resistivities that inhibit the performance of sacrificial anodes located within the patch repair areas. A method of repair is disclosed which comprises removing the corrosion damaged concrete to form a cavity to receive a concrete repair material and forming within this cavity a smaller distinct cavity for assembling a sacrificial anode assembly and placing within this second cavity a pliable viscous ionically conductive backfill and a sacrificial anode and an activating agent to form a sacrificial anode assembly and connecting the anode to the steel and covering the anode and the backfill in the second cavity with a repair material to restore the profile of the concrete structure. In this arrangement a high resistivity repair material promotes the flow of protection current to steel in adjacent contaminated concrete that is at risk of corrosion.

Abstract: Sacrificial anode assemblies have the advantage that they can provide galvanic protection to steel in concrete and do not require long term maintenance of a DC power supply. However sacrificial anode assemblies often loose adhesion to the concrete surface. This invention discloses the use of a sacrificial anode (4) and a backfill (3) and a tape (5) and an adhesive to protect steel (8) in concrete. The backfill is preferably placed in a shallow cavity (1) in the concrete surface (2) and the sacrificial anode is inserted into the backfill. The cavity is covered with a tape that extends over the adjacent concrete surfaces on opposite sides of the sacrificial anode and backfill and the tape is attached to the concrete surface with the adhesive. The tape and the adhesive holds the anode in place and prevents a weathering environment from damaging the backfill.

Abstract: The connections to anodes used in impressed current electrochemical treatments of steel in concrete construction are at risk from rapid corrosion arising from induced anodic dissolution when these connections are embedded in reinforced concrete. A corrosion resistant connection that does not require any further protective insulation can be formed using titanium conductors [2,6] and connecting the conductors together at a conductor-conductor connection [5] using a clamping device comprising a non-metallic material wherein the clamping device only brings corrosion resistant material into contact with the conductors.