Abstract:
A method of protecting steel in concrete using a sacrificial anode assembly is disclosed. The sacrificial anode assembly comprises a sacrificial metal element (11), an activator, a backfill (13), a connector (17) and a spacer (12). An anode cavity (14) is formed in the concrete for the purposes of installing the sacrificial anode assembly therein. The sacrificial metal element and activator are embedded in the backfill in the cavity. The spacer holds the activator away from the sides of the cavity. The connector is used to connect the sacrificial metal element to the reinforcing steel (16). The backfill is a pliable, viscous backfill that does not harden before the installation process is completed.
Abstract:
The use of an electric field modifier to boost the current output of a discrete sacrificial anode to enhance its protective effect and to direct the current output in a preferred direction to improve current distribution in the galvanic protection of steel in hardened reinforced concrete elements exposed to the air is disclosed. In one method a combination comprising a sacrificial anode (21) and an electric field modifier (25) and an ionically conductive filler (28) is embedded in a cavity formed in a concrete element and the sacrificial anode is directly connected to the steel (22). The modifier comprises an element with a side that is an anode (27) supporting an oxidation reaction in electronic contact with a side that is a cathode (26) supporting a reduction reaction. The cathode of the modifier faces the sacrificial anode and is separated from it by the filler (28). The filler 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. The reduction reaction on the cathode of the modifier may substantially comprise the reduction of oxygen from the air.
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:
A method of monitoring the protection delivered to steel bars (1) in concrete construction protected by a discrete sacrificial anode cathodic protection system comprising measuring potentials at potential measurement points located at close intervals in a representative area while the installed sacrificial anodes (2) are operating wherein the potential measurement points include at least three points (3) all located between but away from the same nearby installed anodes (2) and are all preferably located between the same pair of adjacent parallel steel bars. The results are used to identify the position of local anodes. The identification of anodes at locations where none are installed indicates that the steel may not be protected and the discrete sacrificial anode cathodic protection system is not operating effectively.
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:
A single anode system used in multiple electrochemical treatments to control steel corrosion in concrete comprises a sacrificial metal that is capable of supporting high impressed anode current densities with an impressed current anode connection detail and a porous embedding material containing an electrolyte. Initially current is driven from the sacrificial metal [1] to the steel [10] using a power source [5] converting oxygen and water [14] into hydroxyl ions [15] on the steel and drawing chloride ions [16] into the porous material [2] around the anode such that corroding sites are moved from the steel to the anode restoring steel passivity and activating the anode. Cathodic prevention is then applied. This is preferably sacrificial cathodic prevention that is applied by disconnecting the power source and connecting the activated sacrificial anode directly to the steel.
Abstract:
A method for computing a value factor of at-least-one option contract having a market, an expiration date, a price of an underlying contract on a current date, and a strike price. The method includes calculating a theoretical return based upon the expiration date, the strike price, the price of the underlying contract on the current date, and a risk-free interest rate on the current date. Targeting a yield (z) is based upon the price of the underlying contract and a designated multiple of the theoretical return of the at-least-one option contract. Calculating the value factor is based upon the yield (z), an underlying contract price, and the expiration date.
Abstract:
High performance cementitious concretes or mortars and bonding agents developed for use as patch repair materials for corrosion damaged concrete often have high resistivities that inhibit the performance of sacrificial anodes located within patch repair areas. A method of repair is disclosed that comprises removing the corrosion damaged concrete to expose steel and form a cavity to receive high performance concrete repair materials and forming within the parent concrete exposed in this cavity a smaller distinct cavity for assembling a sacrificial anode assembly and placing within this anode 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 assembly in the anode 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:
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.