A hybrid sacrificial galvanic anode, an anodic system including the hybrid sacrificial anode, and a method of cathodically protecting steel reinforcement in concrete structures is provided. The hybrid anode provides initial steel polarization followed by long term galvanic protection without the use of batteries or external power supplies.

Disclosed is an adhesive hydrogel containing a polymer matrix, water, and a polyhydric alcohol, wherein the polymer matrix contains a copolymer of a monofunctional monomer with a single polymerizable C—C double bond and a polyfunctional monomer with two or more polymerizable C—C double bonds, the monofunctional monomer contains a nonionic (meth)acrylamide-based monomer, and the polyfunctional monomer has a composition formula: C.sub.lH.sub.mO.sub.n, where O is an oxygen atom in an ether bond, l is an integer greater than or equal to 4, m is an integer greater than or equal to 6, and n is an integer greater than or equal to 0.

Sacrificial anodes for installing in an ionically conductive medium at an installation site containing metal requiring cathodic protection are formed by locating anode cores in a tray having dividing members defining a row of side by side chambers with each chamber containing a respective one of the anode cores and casting into the receptacle a covering mortar for the anode cores with each anode core receiving a coating at least partly surrounding the anode core with the connecting wire exposed. The mortar is cast to form frangible bridges between each anode and the next. The trays are stacked and transported to the site where the installer separates and individually installs the anodes into the medium.

In a method for cathodically protecting and/or passivating a metal section in an ionically conductive material such as steel reinforcement in concrete or mortar, an impressed current or sacrificial anode communicates ionic current to the metal section and a storage component of electrical energy which can be a cell, battery or capacitor is provided as a component of the anode. A current limiter is provided which prevents excess current draining the supply. This can be a semi-conductive device such as a transistor or diode is connected in the path from the anode to the metal section to limit the cathodic protection current to a value of the order of 1 milliamp. When a diode or similar device is used the current can be limited to the reverse leakage current of the diode.

In a method for cathodically protecting and/or passivating a metal section in an ionically conductive material such as steel reinforcement in concrete or mortar, an impressed current or sacrificial anode communicates ionic current to the metal section and a storage component of electrical energy which can be a cell, battery or capacitor is provided as a component of the anode. A current limiter is provided which prevents excess current draining the supply. This can be a semi-conductive device such as a transistor or diode is connected in the path from the anode to the metal section to limit the cathodic protection current to a value of the order of 1 milliamp. When a diode or similar device is used the current can be limited to the reverse leakage current of the diode.

In a method for cathodically protecting and/or passivating a metal section in an ionically conductive material such as steel reinforcement in concrete or mortar, an impressed current or sacrificial anode communicates ionic current to the metal section and a storage component of electrical energy which can be a cell, battery or capacitor is provided as a component of the anode. A current limiter is provided which prevents excess current draining the supply. This can be a semi-conductive device such as a transistor or diode is connected in the path from the anode to the metal section to limit the cathodic protection current to a value of the order of 1 milliamp. When a diode or similar device is used the current can be limited to the reverse leakage current of the diode.

Sacrificial anodes for installing in an ionically conductive medium at an installation site containing metal requiring cathodic protection are formed by locating anode cores in a tray having dividing members defining a row of side by side chambers with each chamber containing a respective one of the anode cores and casting into the receptacle a covering mortar for the anode cores with each anode core receiving a coating at least partly surrounding the anode core with the connecting wire exposed. The mortar is cast to form frangible bridges between each anode and the next. The trays are stacked and transported to the site where the installer separates and individually installs the anodes into the medium.

Disclosed is an anode assembly for the corrosion protection of metal parts embedded in concrete. An ion-conducting material is placed between the metal part that is to be protected and the anode, which ion-conducting material exhibits higher ionic conductivity than the surrounding concrete, thus directing the protective current specifically towards the metal part. A galvanic sacrificial anode may be provided, made, e.g., from zinc and its alloys or aluminum and its alloys. The purpose of the material with higher ionic conductivity than the surrounding concrete is to selectively direct the protective galvanic current towards the metal part that is to be protected. The selective enhanced corrosion protection is especially beneficial for the protection of metal parts that are highly important for the structural integrity of concrete members, such as assembly of pre- or post-tensioning of concrete members, such as anchor-heads. The ion conducting material exhibits 20%, and more preferably 50%, higher conductivity than the surrounding concrete. A suitable ion-conducting material that exhibits ion-exchange properties may comprise tecto-alumo-silicate materials. The anode may be placed in close contact to or may be embedded into the ion-conducting material as well.

The present invention relates to a method of installing an unbonded flexible pipe with a bore for transportation of fluid wherein the unbonded flexible pipe comprises an outer sheath, an inner sealing sheath inside the outer polymer sheath, an annulus between said outer sheath and said inner sealing sheath and at least one metallic armor layer comprising iron located in said annulus, wherein the method comprises filling at least a part of the annulus with a corrosion promoting liquid before or after installing the unbonded flexible pipe between a first installation and a second installation.

Corrosion protection of steel in concrete is provided by locating an anode assembly including both a sacrificial anode and an impressed current anode in contact with the concrete and providing an impressed current from a power supply to the anode. The impressed current anode forms a perforated sleeve surrounding a rod of the sacrificial anode material with an activated ionically-conductive filler material between. The system can be used without the power supply in sacrificial mode or when the power supply is connected, the impressed current anode can be powered to provide an impressed current system and/or to recharge the sacrificial anode from sacrificial anode corrosion products.