Cathodic protection of concrete using surface-mounted anodes.

Abstract

The anode apparatus for attachment to the exterior surface of a concrete structure to provide cathodic protection for metal components within the structure utilizes a typically elongated, pre-assembled body carrying a longitudinal anode, which may be a sacrificial or impressed current, together with a support having a front surface for attachment to the exterior surface and an impervious plastic covering on a rear surface that covers the anode and support when the front surface is attached to the exterior surface of the concrete structure. A groove defined in the front surface is positioned to receive a layer of a compatible, ionically conductive adhesive for attachment to the exterior surface. The edges of the covering are positioned to be the same distance from the exterior surface as the metal, so that the wetting and drying effects of environmental moisture are the same on the anode and one or more metal components.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for cathodic protection of reinforced concrete structures such as bridges, piers, car park decks and foundation structures. [Background technology]

[0002] Corrosion of rebar in reinforced concrete structures is the result of electrical current flowing from one point on the rebar to another. Such corrosion is accelerated by moisture and salt contamination of the concrete. Conventional cathodic protection involves applying an external direct current to the rebar from a current-distributing anode in close proximity to the concrete surface. The current from the distributing anode counteracts the corrosion current. This can be provided by anode strips attached to the exterior surface of the concrete.

[0003] In another configuration, the anode comprises a strip or band of sacrificial anode material. The strip or band has a pressure-sensitive adhesive layer, which can be a hydrogel, that adhesively secures the strip or band directly to the structure. The adhesive layer is electrically conductive and has a protective covering that allows the anode to be wound without adhesion between adjacent windings of the anode. Examples of adhesives disclosed in the patent include acrylic and vinyl adhesives.

[0004] In addition to applying sacrificial metal strips or tapes, or spray systems, to the surface of the object to be protected, it is also known to cut grooves in the concrete and place sacrificial metal cathodes in the grooves, for example, near rebar, with magnesium or zinc anodes placed in the grooves. A resilient material, preferably a foam, can be placed in the groove along with the anodes. This material can be compressed by the expansive corrosion products resulting from corrosion of the sacrificial anodes.

[0005] It is also known to apply a jacket surrounding a concrete column containing an impressed current anode within the jacket. Summary of the Invention

[0006] It is an object of the present invention to provide an arrangement in which anodes can be easily and quickly attached to the exterior surface of a concrete structure and which can operate to provide long-term corrosion protection without degradation due to moist environmental conditions. The exposed surface is typically a flat exterior surface, but may include a groove or recess into which the anode is applied. The anode is typically a sacrificial anode, although many of the features herein can also be used with impressed-current anodes.

[0007] According to a first aspect, there is provided a pre-assembled anode apparatus for attachment to an exterior surface of a concrete structure to provide cathodic protection of one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front surface for attachment to an exterior surface of the concrete structure and a rear surface facing away from the concrete structure; an anode carried by the body and extending at least partially along the body, the anode being formed of a material sacrificial with respect to the one or more metal components for generating a galvanic current between the anode and the one or more metal components to provide cathodic protection for said one or more metal components; an ionically conductive support material carried by the body and at least partially surrounding the anode; Equipped with the support material includes an activator for maintaining a galvanic current; the support has a front surface positioned to allow ions to be transferred from the anode through the support to one or more metal components within the concrete structure; the body includes an impermeable covering on a rear surface that covers the anode and the support; An impervious covering is positioned to cover the anode and support when the front surface is attached to the surface of the concrete structure.

[0008] According to a second aspect of the present invention, there is provided a pre-assembled anode apparatus for attachment to an exterior surface of a concrete structure to provide cathodic protection of one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front surface for attachment to an exterior surface of the concrete structure and a rear surface facing away from the concrete structure; an anode carried by the body and extending at least partially along the body; an ionically conductive support carried by the body and at least partially surrounding the anode, the support having a front surface positioned to allow ions to be transferred from the anode through the support to one or more metal components within the concrete structure; a groove defined in the body between the front face of the support and the outer surface of the concrete structure for receiving an adhesive material applied to the groove for attaching the front face to the outer surface of the concrete structure by the adhesive material; Equipped with the body includes an impermeable covering on a rear surface that covers the anode and the support; An impervious covering is positioned to cover the anode and support when the front surface is attached to the exterior surface of the concrete structure.

[0009] According to a further aspect of the present invention there is provided a method of cathodic protection of one or more metal components within a concrete structure, wherein the one or more metal components are spaced from an exposed surface of the concrete structure, the method comprising: a step of attaching a body to an exposed surface of a concrete structure, the body having a front surface for attachment to the exposed surface and a rear surface facing away from the concrete structure, the body includes an anode carried thereon and extending at least partially along the body; the anode is formed of a material sacrificial with respect to the one or more metal parts to generate a galvanic current between the anode and the one or more metal parts to provide cathodic protection of the one or more metal parts; an ionically conductive support material carried by the body and at least partially surrounding the anode; the support material includes an activator for maintaining a galvanic current; the support has a front surface positioned to allow ions to be transferred from the anode through the support to one or more metal components within the concrete structure; covering the support and the anode with an impervious covering positioned to cover the anode and the support when the front surface is attached to the exposed surface of the concrete structure; A method comprising:

[0010] According to a further aspect of the present invention there is provided a method of cathodic protection of one or more metal components within a concrete structure, the method comprising: attaching a preformed body to an exposed surface of the concrete structure, the preformed body having a front surface for attachment to the exposed surface of the concrete structure and a rear surface facing away from the concrete structure; the preformed body includes an anode carried thereon and extending at least partially along the preformed body; the preformed body includes an ionically conductive support material carried so as to at least partially surround an anode; the support has a front surface positioned to allow ions to be transmitted from the anode through the support into the concrete structure to one or more metal components within the concrete structure; Attaching a front surface to a concrete structure using an ionically conductive adhesive material, the support and the anode are covered with an impervious covering disposed over the anode, the support and the adhesive material when the front surface is attached to the exposed surface of the concrete structure; Including, The method wherein the impermeable coating extends over both sides of the anode, the support and the adhesive material.

[0011] In this method, the distance from the anode material to the edge of the coating material is positioned to approximately match the distance of the one or more metal components from the surface of the concrete structure so that the effects of wetting and drying through the concrete structure are the same for both the anode and the one or more metal components. This approximate match is in that the distance may not be exactly the same because the porosity and drying characteristics of the concrete structure and the material adjacent to the anode may differ, but it is intended that moisture conditions be maintained approximately equal to maintain adequate resistance between the anode and the one or more metal components.

[0012] The body may be, and typically is, an elongated body arranged to be attached to and extend along one exposed surface of a concrete structure such as a pillar or post, although alternatively the body may be rectangular or circular so as to be applied substantially as a patch to a particular area.

[0013] This configuration takes advantage of the natural wetting and drying cycles experienced by reinforced concrete elements. If the rebar is within the minimum coverage depth and corrosion is occurring, the presence of moisture at a certain depth is evident. As noted above, the galvanic anode should also be at least the same depth, which of course would not be the case if it were placed on the concrete surface. The novel method disclosed herein for artificially achieving coverage equivalent to the rebar is to enclose the anode in a waterproof, impervious housing or layer that is fixed to the concrete surface and extends beyond either side of the anode by a distance equal to or proportional to the coverage depth between the surface and the rebar. In that case, the wetting and drying effects are the same for the anode and for the rebar at the same distance from the surface of the concrete structure.

[0014] In addition to the above-mentioned problem of differential drying of the anode and rebar ionically conductive materials, the coating layer can also provide the advantage of reducing the possibility of leaching of the activator from the ionically conductive material of the anode. The activator is used to maintain the current when using a sacrificial anode and can be washed away from the area surrounding the anode if the anode is exposed to external moisture.

[0015] Additionally, the coating layer can reduce carbonation, which is the formation of carbonate salts under high pH conditions surrounding the anode. Both of these problems can significantly reduce the ability of the sacrificial anode to electrically generate the current required for cathodic protection.

[0016] In a preferred configuration, a fastening mechanism is provided for attaching the front face of the support to the surface of the concrete structure. This may include fasteners, such as screws, that engage the concrete structure. Because the support is typically solid mortar within a pre-assembled structure, the fastening mechanism desirably includes a compatible material disposed between the front face and the surface to compensate for any unevenness in the surface. Thus, the fastening member desirably includes a compatible adhesive substance that adheres to both the front face and the surface of the concrete structure while filling in any unevenness between the surfaces.

[0017] The adhesive substance can be provided as an integral part of a pre-assembled structure, typically covered with a release sheet, or more preferably, the fastening mechanism includes a groove for receiving an adhesive that can be applied in situ to the groove with a trowel. In this way, the user can apply the adhesive as new material provided in the amount or quantity needed to properly bond and fill the area between the support and the surface.

[0018] Preferably, the groove is defined by spaced-apart longitudinal side edges on either side of the front surface of the support, with a bead disposed on each side to confine the adhesive therebetween. This allows the user to quickly and easily apply the required amount of adhesive between the two beads. Preferably, the covering layer includes two outer cover portions on the outside of the stop beads or edges to confine the adhesive and extend outward from the beads to cover any adhesive that leaks or overflows from the layer applied between the beads. This helps the user easily apply the required amount of adhesive and acts to confine and cover excess adhesive to provide a clean finished appearance when the body is applied to the outside of a concrete structure.

[0019] Preferably, the impermeable covering is semi-rigid so that it lies flat on the surface of the concrete structure during application, and is formed from an extruded plastic strip having a raised central portion in which the supports and anodes are housed, and two lateral extending flange portions disposed on either side of the central portion for engaging the surface. The raised central portion has sufficient volume to house the anode strip spaced from the surface of the concrete structure and to house the amount of support necessary to provide the necessary level of activator within the support to maintain anode activity.

[0020] Preferably, the plastic strips forming the impermeable covering include flanges or fins that extend into and engage the support to maintain the support and the anode carried thereby properly within the area of ​​the ridge during handling, transportation and installation of the body onto the concrete surface.

[0021] The body can be attached to the concrete structure by just the top adhesive layer, but in some cases the plastic cladding includes fastener holes on either side of it, spaced from the support, so that attachment can be more securely achieved by threaded fasteners that pass through the holes and engage with the concrete structure.

[0022] In other cases, the compatible material between the front face of the support and the surface of the concrete structure can be a filler that provides the necessary ion-conducting pathway between the support and the surface of the concrete structure.

[0023] The compositions herein are intended for use as strips that are applied separately to the exterior surface of a concrete structure, leaving the remainder of the surface exposed. Thus, the side edges of the strips are generally spaced apart from and not attached to adjacent strips. In some cases, the strips can be placed end-to-end to provide a length suitable to cover the length of the structure to be protected. In other cases, the length can be selected to meet the requirements using a single body or strip.

[0024] The anode includes one or more connector wires extending from the end of the anode for connection to another part of the anode material or to rebar, in the case of sacrificial anode material, or to another part of the anode material or to a power source, if used as an impressed current anode.

[0025] A longitudinal cavity may be provided in the cladding to accommodate the connecting wire from the anode.

[0026] A separate end cover is positioned over the impermeable covering to cover the wires and provide a clean appearance, and engages with the impermeable covering at one end of the elongated body to cover the end face of the impermeable covering and the end wires. Preferably, the end cover includes an engaging lip for sliding onto the plastic covering from one end or for snap-fitting onto the plastic covering.

[0027] When the body is used end to end, the end covers are positioned to bridge the ends to cover the wires connected therebetween.

[0028] If precise alignment of the body on the concrete structure is not required, the body can be simply attached using the fastening mechanism defined above. However, if precise positioning is required, an alignment member can be provided for pre-attachment to the concrete structure at the required selected location. This can include at least one mounting leg extending along the concrete surface in the longitudinal direction of the intended location of the elongated body. In this manner, the alignment member is attached first, defining the attachment for attaching and supporting the elongated body to the concrete structure. Once the precise location is determined, the attachment can be completed using the adhesive and / or fixing screws described above, engaging and holding the entire length of the body against the concrete surface.

[0029] Preferably, the impermeable body includes at least one cavity therein for retaining moisture at or adjacent to the concrete surface, the cavity may extend longitudinally or may be spaced apart.

[0030] The configurations described herein can be used with impressed-current anodes. However, sacrificial anodes are particularly advantageous in that concrete exposed to the atmosphere is known to lose moisture through evaporation and moisture transport through exposed surfaces during relatively dry periods, and to gain moisture primarily through capillary absorption during wet periods. Moisture migration can also occur through exposed surfaces when the ambient humidity is significantly higher than the humidity within the outer capillary pores. Absorption is rapid and carries soluble substances, such as chlorides, which are aggressive to rebar. Natural exposure tests of various types of concrete exposed to sea spray have shown that absorption and capillary suction are the primary mechanisms of water (and chloride) uptake in the first 1–2 cm, while ionic diffusion, a much slower process, is the primary long-term transport mechanism deeper into the concrete. Another study of the effects of sea spray found rapid penetration of chloride-laden water into the first 1–2 cm of concrete. Recent field studies tend to support the view that absorption can be an important infiltration mechanism in concrete structures.

[0031] Furthermore, studies have shown that capillary suction is strong, causing water to move rapidly to the exposed, dry surface of concrete. Over time, the rate of infiltration or volume increase decreases due to a decrease in capillary force caused by increasing saturation. Furthermore, saturation or moisture gradients have been shown to exist within concrete over a range of several millimeters to several centimeters.

[0032] Capillary suction is therefore the primary mechanism by which liquids penetrate exposed concrete when the concrete comes into contact with water after a drying period. Chlorides dissolved in water can be carried into the concrete with the water and then penetrate further into the concrete by diffusion. In practice, an overlap of these mechanisms occurs, as the relative importance of the two mechanisms changes with depth. In contrast to capillary suction, diffusion becomes increasingly important as more of the concrete's pores fill with water. Therefore, it would be reasonable to expect that the depth of water penetration by capillary suction in dry concrete will depend on the depth of the concrete affected by drying.

[0033] Other results show that water penetration depth is greatest in concrete with the highest water / cement ratio, progressing to nearly 30 mm over 25 hours. As the water / cement ratio and porosity decrease and the strength increases, penetration depth decreases, leveling off at around 20 mm for strengths above 45 MPa.

[0034] The initial exposure of surface-dry concrete to water or chloride solutions is important because a few centimeters of cover concrete are easily infiltrated. However, actual concrete structures are likely to be exposed to intermittent wet environments, with drying periods between. The cover depth of concrete exposed to cyclic wetting and drying conditions, such as tides and rainfall, alternates between saturated and partially saturated, while the "core" of the concrete remains substantially saturated. The degree of drying within the cover directly affects the magnitude of capillary forces, which in turn likely determine the rate of water infiltration during subsequent wetting cycles. If the ambient RH is held at a constant level during a drying cycle, a very steady water loss occurs with the square root of time.

[0035] As with wetting cycles, water loss increases with increasing water / cement ratio. For constant temperature, wind speed, and RH, all environmental factors that can affect drying rate, the parameters that are most likely to affect water loss are porosity, pore size, pore size distribution, pore continuity and tortuosity, and the presence or absence of microcracks in the surface region.

[0036] The drying process and subsequent capillary absorption are closely related, since drying reduces pore saturation and increases capillary suction. Indeed, as drying progresses, the level of capillary suction in the dry zone increases, leading to increased absorption during wetting. This zone of influence, called the convection zone, varies depending on the type of concrete, its initial drying state, and the water / binder ratio. It can vary from 10 mm in good quality concrete to 100 mm in poor quality concrete.

[0037] Testing further confirms that after prolonged drying in a 50% RH environment, significantly more water or salt solution is absorbed during the first wetting cycle than during any subsequent cycle. The amount absorbed gradually decreases and reaches a nearly constant level. Water loss during the drying cycle is much slower than water absorption. In subsequent cycles, water absorption during each wetting cycle balances water loss during the next drying cycle, maintaining a near-quasi-equilibrium. Modeling also shows that cyclic exposure of 0.6 w / c concrete to external high and low RH can result in a maximum convection depth of 30 mm over a total of 14 days, with 9-10 days at 95% RH and 4-5 days at 60% RH.

[0038] The presence of dissolved chlorides in seepage water can induce corrosion of rebar, leading to cracking and spalling of the covering concrete. Since chloride penetration causes rebar corrosion, concrete that is not constantly immersed in chloride-containing water, such as seawater, must at least occasionally include wetting and drying cycles to ensure sufficient chloride penetration to the rebar. This means that sufficient moisture levels are maintained at the rebar for destructive corrosion to occur. Therefore, the depth of the rebar cover is a critical parameter in the corrosion process, as it must be bridged by both chlorides and moisture.

[0039] Of the wide range of available technologies, cathodic protection is recognized as the only technique capable of guaranteeing corrosion prevention. The method for achieving cathodic protection is the use of galvanic sacrificial anodes, which are directly connected to the rebar and sacrificially corrode to prevent the rebar from corroding. Traditionally, galvanic anodes typically consist of a zinc core encased in an active medium and are buried in concrete at a minimum depth to the adjacent rebar. This ensures that the moisture level around the anode is equal to or matches that of the rebar. If this is not the case, the concrete around the anode will dry out to a level lower than that around the rebar, increasing the resistivity between the anode and the rebar and restricting the flow of current between the two metals. Surface-applied anodes typically suffer from this moisture imbalance; the anode loses moisture to the atmosphere and becomes essentially inert.

[0040] Some surface anodes, such as a layer of zinc sheeting placed on the surface of concrete, utilize a moisture-retaining / moisture-absorbing gel placed between the inner surface of the zinc and the concrete surface, which also contains an anode activator.

[0041] However, accumulation of water within the gel causes it to expand and lose its bond with the underlying concrete, creating major problems.Another attempt at applying an external anode (in this case an inert anode for impressed current cathodic protection) is to encase it in a moisture-retaining case and occasionally inject liquid into the moisture-retaining layer.

[0042] The configuration disclosed below takes advantage of the natural wetting and drying cycles experienced by reinforced concrete elements. If the rebar is located within the minimum coverage depth and corrosion is occurring, it is clear that moisture is present at that particular depth. As mentioned above, galvanic anodes must be installed at the appropriate depth, which of course is not the case when installed at the concrete surface. A novel way to artificially achieve coverage equivalent to the rebar is to house the anode in a waterproof housing that is fixed to the concrete surface and extends beyond the anode on both sides by a minimum length equivalent to the coverage depth. In this case, the effects of wetting and drying are approximately the same for rebar and anodes at the same effective distance from the concrete surface. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 is an isometric view of one embodiment of an anode apparatus for attachment to the surface of a concrete structure for use in cathodic protection of steel components within the concrete structure, the anode apparatus being pre-fabricated and pre-assembled prior to attachment to the concrete structure, the anode apparatus including separate components for attachment, for covering wire and screw holes from the anode, and for serving as end caps. [Figure 2]2 is a cross-sectional view taken along line 2-2 of FIG. 1 showing the pre-assembled anode device prior to installation on a concrete surface. [Figure 3] 3 is a cross-sectional view taken along line 3-3 of FIG. 1 showing the pre-assembled anode device after installation on a concrete surface. [Figure 4] 4 is a cross-sectional view taken along line 4-4 of FIG. 1 showing the pre-assembled anode device with the cover strip in place after installation on a concrete surface. [Figure 5] FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 1 showing the pre-assembled anode device after installation on a concrete surface, showing a mounting bracket that is attached to the concrete surface and engages the anode device for alignment and support of the anode device. DETAILED DESCRIPTION OF THE INVENTION

[0044] The configuration herein provides a pre-assembled anode device 10 for attachment to the exterior surface 11 of a concrete structure 12 to provide cathodic protection for one or more metal components 13 within the concrete structure 12.

[0045] The device includes a body 14, a cover strip 15 engageable with the body to cover mounting holes in the body, a mounting strip 16 (FIG. 4), and end cover panels 17. The cover strip 15 can also function to cover wires from the anode, including connector wires housed within recesses along the body 14, monitoring wires 151, and, optionally, reference electrode wire 152.

[0046] The body 14, best seen in cross section in FIG. 2, constitutes a pre-assembled anode device defining an elongated body having a front surface 14A for attachment to the exterior surface 11 and a rear surface 14B facing away from the concrete structure. The body is defined primarily by an extruded strip 14C of impermeable material, such as a suitable plastic. The extruded strip may be made of an electrically insulating material to cover exposed conductors, although this is not required. The body is typically extruded and therefore may have an elongated shape, but this is not required; it may also be rectangular, square, or circular to accommodate similarly shaped anodes.

[0047] Body 14 has a raised central portion 14D and two side wing portions 14E and 14F. Within raised portion 14D is an elongated anode 14G carried by and extending at least partially along the elongated body. Typically, the anode extends its entire length and includes connecting wires 14H and 14J at one or both ends for electrical connection to rebar, a subsequent anode, and / or a power source, as needed.

[0048] In one embodiment, the anode is formed of a material, such as zinc, that is sacrificial to the one or more metal components 13 to generate a galvanic current between the anode 14G and the one or more metal components 13 to provide cathodic protection for the one or more metal components. In another configuration, the anode is connected to a power source and can optionally be made of a non-sacrificial or inert material, with the protective current being supplied by an applied current rather than a galvanic current.

[0049] The anode is carried by the elongated body and is attached to a support 14K of ionically conductive material that fills the raised portion 14D to surround the embedded anode. The anode may be provided with a recessed surface portion to increase the surface contact area between the anode and the support 14K. The anode is located within the raised central portion of the plastic cover 14C and spaced from the front surface 14A. The support is held in place by a pair of flanges or fins 14M that project inwardly from the wall of the cover 14C into the body of the support and are poured into place within the cover to surround the anode.

[0050] In the case of sacrificial anodes, a support material 14K containing an activator of a type well known to those skilled in the art is used to maintain galvanic current by promoting corrosion of the anode.

[0051] In the pre-assembled unit shown in Figure 2, the support has a front surface defining a front surface 14A that, when attached to the concrete surface, acts to allow the transfer of ions from the anode through the support to one or more metal components within the concrete.

[0052] Thus, the elongated body includes and is supported by an impermeable covering 14C on the rear face of the body, which covers the anode and support, and is positioned to cover the anode and support when the front face 14A is attached to the concrete surface 11. The impermeable covering isolates the anode and support from the surrounding moist environment, including rain, spray, and tidal influences.

[0053] The anode device shown in Figure 2 is designed to be handled, transported, and installed as a general assembly, with a structure that is sufficiently rigid to accommodate the forces involved while maintaining a generally elongated linear configuration. The structure can be made to different lengths, or can be joined end-to-end as described below, if needed for a particular installation. It can also be rectangular or circular, as described above.

[0054] The structure is configured to be attached to the front surface 11 of the concrete as a separate body, leaving the rest of the surface exposed. Of course, it is important that the front surface of the support 14K be in intimate ionic contact with the concrete surface to ensure effective ionic communication between the anode and the rebar in the concrete. To this end, the primary attachment is provided by a layer of adhesive material 14N, which is configured to be flexible or conformable upon application to accommodate surface variations and to harden after application to form an integral body between the concrete surface and the elongated body containing the anode. In one preferred configuration, the adhesive material can be applied by troweling to the required thickness on the front surface 14A, after which the anode device is applied to the surface. The adhesive material can be a suitable cementitious mortar, but can also include other materials with conformability, adhesion, and ionic conductivity.

[0055] The securing mechanism includes an adhesive receiving groove 14P defined by two flanges or beads 14R that project downward from the front surface by a height equal to the desired thickness of adhesive 14N, thus providing a guide for the user to apply the adhesive to the required thickness. The adhesive is then positioned to adhere between the support 14K and the surface 11.

[0056] As an alternative not shown, the adhesive may be shown as part of the anode device as a pre-applied layer and covered with a release sheet.

[0057] Thus, the impermeable covering has a raised central portion 14D in which the support 14K and anode 14G are housed, and two side portions 14E and 14F for engaging the opposing surfaces of the support. Wall portions 14E and 14F extend outward from the raised portion to an outer edge 14T, as indicated by wall 14S. A bead 14R extends downwardly from wall 14S at a location spaced outward from central portion 14D so that a portion of wall 14S is adhered to the concrete surface by adhesive layer 14N. Wall portion 14S extends outward from bead 14R along the concrete surface, covering any adhesive 14N that may leak from bead 14R due to pressure or slight overfilling used to ensure complete coverage.

[0058] Cover 14 may further include optional reinforcing cavities 14X on either side of raised central portion 14D. Outside cavity 14X and inside outer edge 14T are provided respective grooves 14Y to receive wires 151, 152 and optional fastener screws 14Z that pass through fastener holes 14U covered by strip 15. In this manner, the extruded cover is relatively rigid and can be laid flat on a concrete surface, with the underside and underside 14S of support 14K adhered to the concrete surface by applied adhesive layer 14N.

[0059] To provide a more secure attachment of the elongated body and to hold the body in place during and after the adhesive cures, the impermeable covering includes fastener holes 14U in the grooves 14Y at locations outside the beads 14R, so as to be outside the adhesive and spaced from the supports 14K, which can receive screw fasteners 14Z that engage the concrete.

[0060] To ensure a sufficiently attractive and smooth rear surface that is exposed to the concrete surface, the insert strip 15 is held in the body by grooves 14Y having cooperating projections 14V that engage holes 14U and position the strip within the groove as a snap fit or as a slide fit. These can also cover the aforementioned wires 151, 152 that can be held, protected and hidden by the insert strip 15.

[0061] As shown in Figures 1 and 5, a separate end cover 17 is provided that engages the impermeable sheathing and is positioned to cover the end face of the impermeable sheathing at one end of the elongated body 14. The cover 17 has an interior shape that matches the exterior of the elongated body 14 and its sheathing, and includes an engagement lip 171 for attaching to the impermeable sheathing at a recess 172 at the end of the elongated body. This engagement lip 171 can be slid into place from the end or snapped onto the side of the body. The end cover 17 spans the two end-to-end ends of the elongated body 14 (not shown) and can be used to cover an attachment wire at one end of the anode for connection to one or more metal components.

[0062] To facilitate easy attachment of the elongated body to a concrete surface, an optional mounting member 16 is provided for attachment to the concrete prior to installation of the body 14. The mounting member 16 can be installed in a predetermined location to serve as a guide for proper alignment and placement of the body 14. When installed, the mounting member 16 includes at least one mounting leg 16A extending longitudinally along a portion of the surface of the elongated body at its intended location to attach to and support the elongated body when applied to the concrete. Thus, the mounting member is installed in a predetermined location at one end of the body 14, and then the body 14 is slid into place on the leg 16A with the leg received in a receptacle 14W within the body 14 between the outer edge 14T and the bead 14R. The impermeable body may include at least one longitudinally extending cavity or groove therein, which may be defined by a receptacle 14W located at the concrete surface to retain moisture passing along the body after introduction to help maintain moisture in the support 14K maintaining galvanic activity. The outer edge 14T of the recess 172 may provide a location for an additional sealing bead of sealant or caulking material (not shown).

[0063] The arrangement herein can be used in a manner as shown in FIG. 3, where a predetermined distance D1 between the surface of the concrete and one or more metal parts, i.e., rebars 13, is arranged to match the predetermined distance D2 between the edge of the cover 14C and the anode 14G in the center of the cover, so that the wetting and drying effects are the same for the one or more metal parts as for the anode.

Claims

1. 1. A pre-assembled anode apparatus for attachment to an exterior surface of a concrete structure to provide cathodic protection for one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front surface for attachment to the exterior surface and a rear surface facing away from the concrete structure; an anode carried by the body, the anode being formed of a material sacrificial with respect to the one or more metal components for generating a galvanic current between the anode and the one or more metal components to provide cathodic protection for the one or more metal components; an ionically conductive support carried by the body and engaging the anode, the support having a front surface positioned to allow ions to be transferred from the anode through the support to the one or more metal components within the concrete structure; Equipped with the body includes an impermeable covering on the rear surface that covers the anode and the support; the impermeable covering is positioned to cover the anode and the support when the front surface is attached to the exterior surface of the concrete structure.

2. The anode apparatus of claim 1 , further comprising a fastening mechanism for attaching the front surface to the exterior surface.

3. The anode apparatus of claim 2 , wherein the securing mechanism includes a groove for receiving an adhesive.

4. The anode device of claim 3 , wherein the adhesive is disposed to adhere between the support and the outer surface.

5. 5. An anode apparatus according to claim 3 or 4, wherein the groove is defined by spaced apart longitudinally extending side edges arranged to trap the adhesive therebetween.

6. 6. An anode apparatus according to any one of claims 1 to 5, wherein the impermeable covering has a raised central portion beneath which the support and anode are housed, and two side-dependent flange portions for engaging the outer surface.

7. 7. The anode apparatus of claim 6, wherein the two side-dependent flange portions include stop beads for containing adhesive and outer cover portions extending outward from the stop beads to cover the adhesive leaking from the stop beads.

8. 8. The anode apparatus of claim 1, wherein the impermeable covering includes a flange that extends into and engages the support to maintain the support, and the anode therein, within the body.

9. 9. The anode device according to claim 1, wherein the impermeable covering comprises fastener holes through which fasteners can pass to engage the concrete structure.

10. An anode apparatus according to any preceding claim, including a separate end cover arranged to engage the impermeable covering and cover one end of the body.

11. The anode apparatus of claim 10 , wherein the end cover includes an engaging lip for attachment to the impermeable covering.

12. 12. An anode device according to claim 10 or 11, wherein the end cover is arranged to bridge the ends of the two bodies.

13. 13. The anode apparatus of claim 10, 11 or 12, wherein the anode includes one or more attachment wires for connecting to the one or more metal components, and the end cover is positioned to cover the one or more attachment wires.

14. 14. The anode device according to claim 1, further comprising a mounting alignment member for mounting the body to the concrete structure, the mounting alignment member including at least one mounting leg for aligning and supporting the body to the concrete structure.

15. An anode device according to any preceding claim, wherein the impermeable body comprises at least one moisture cavity for retaining moisture.

16. 1. A pre-assembled anode apparatus for attachment to an exterior surface of a concrete structure to provide cathodic protection for one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front surface for attachment to the exterior surface and a rear surface facing away from the concrete structure; an anode carried by the body; a groove defined in the body between the front surface and the outer surface, the groove receiving an adhesive material applied thereto for attaching the front surface to the outer surface by the adhesive material; Equipped with the body includes an impermeable coating on the rear surface covering the anode; The impermeable covering is positioned to cover the anode when the front surface is attached to the exterior surface of the concrete structure.

17. 17. The anode apparatus of claim 16, including an ionically conductive support carried by the body and engaging the anode, the support having a front surface positioned to allow ions to be transferred from the anode through the support to the one or more metal components within the concrete structure.

18. 18. An anode apparatus according to any one of claims 16 to 17, wherein the groove is defined by the front surface of the support and longitudinally extending edges on either side of the support to which the layer of adhesive substance is applied.

19. 19. An anode apparatus according to any one of claims 16 to 18, wherein the impermeable covering has a raised central portion beneath which the support and anode are housed, and two side-depending flange portions for engaging the outer surface.

20. 20. The anode apparatus of claim 19, wherein the two side-dependent flange portions include stop beads for containing the adhesive material and outer cover portions extending outward from the stop beads for covering the adhesive material leaking from the stop beads.

21. 18. The anode apparatus of claim 17, wherein the impermeable covering includes a flange that extends into and engages the support to maintain the support and the anode therein within the body.

22. 22. An anode apparatus according to any one of claims 16 to 21, wherein the impermeable covering comprises fastener holes through which threaded fasteners can pass to engage the concrete structure.

23. An anode device according to any one of claims 16 to 22, comprising an end cover which engages the impermeable covering and is positioned to cover one end of the body.

24. 24. The anode apparatus of claim 23, wherein the end cover includes an engaging lip for attachment to the impermeable covering at the one end of the body.

25. 25. An anode device according to claim 23 or 24, wherein the end cover is arranged to bridge the ends of the two bodies.

26. 26. The anode apparatus of claim 23, 24, or 25, wherein the anode includes one or more attachment wires for connecting to the one or more metal components, and the end cover is positioned over the one or more attachment wires.

27. 27. The anode device according to claim 16, further comprising a mounting alignment member for mounting the body to the concrete structure, the mounting alignment member including at least one mounting leg for aligning and supporting the body to the concrete structure.

28. An anode device according to any one of claims 16 to 27, wherein the impermeable body includes at least one moisture cavity therein for retaining moisture.

29. An anode device according to any one of claims 16 to 28, wherein the impermeable covering extends beyond the anode on both sides.

30. An anode device according to any one of claims 16 to 28, wherein the adhesive material is wider than the anode and / or the support material.

31. An anode device according to any one of claims 16 to 30, wherein the impermeable covering includes at least one receiving cavity therein for receiving a connecting wire associated with the anode.

32. An anode device according to any one of claims 16 to 31, wherein the receiving cavity is covered by a cover strip.

33. 1. A method for cathodic protection of one or more metal components within a concrete structure, wherein the one or more metal components are spaced from an exposed surface of the concrete structure, the method comprising: attaching a body to the exposed surface of the concrete structure, the body having a front surface for attachment to the exposed surface and a rear surface facing away from the concrete structure; the body including an anode carried thereon; the anode is formed of a material that is sacrificial with respect to the one or more metal components to generate a galvanic current between the anode and the one or more metal components to provide cathodic protection for the one or more metal components; an ionically conductive support material carried by the body in engagement with the anode; the support has a front surface positioned to allow ions to be transferred from the anode through the support to the one or more metal components within the concrete structure. The process and covering the support and the anode with an impermeable covering disposed to cover the anode and the support when the front surface is attached to the exposed surface of the concrete structure; A method comprising:

34. 34. The method of claim 33, wherein the impermeable covering extends beyond the anode on both sides.

35. 35. The method of claim 34, wherein the distance from the anode material to the edge of the impermeable coating is positioned to match the distance from the exposed surface of the concrete structure to the one or more metal components, so that wetting and drying effects through the concrete structure are similar for the anode and the one or more metal components.

36. 36. A method according to claim 34 or 35, comprising securing the front surface to the exposed surface with a layer of adhesive material.

37. 37. The method of claim 36, wherein the adhesive substance is applied as a layer in a groove defined in the front surface of the support.

38. 38. The method of claim 37, wherein the groove is defined by spaced apart longitudinally extending side edges positioned to trap the adhesive substance therebetween.

39. 39. The method of any one of claims 33 to 38, wherein the impermeable covering has a raised central portion beneath which the support and anode are housed, and two side-depending flange portions for engaging the exposed surface.

40. 40. The method of claim 39, wherein the two side-dependent flange portions include stop beads for containing adhesive and outer cover portions extending outward from the stop beads for covering adhesive that leaks from the stop beads.

41. 41. The method of any one of claims 33 to 40, wherein the impermeable covering includes a flange that extends into and engages the support to maintain the support, and the anode therein, within the body.

42. 42. The method of any one of claims 33 to 41, wherein the impermeable covering comprises fastener holes through which screw fasteners can pass to engage the concrete structure.

43. A method according to any one of claims 31 to 42, including the step of attaching separate end covers to the impermeable covering at the ends of the body.

44. 44. The method of claim 43, wherein the end cover includes an engagement lip for attachment to the impermeable covering at the end of the body.

45. 45. The method of claim 44, wherein the end cover spans two end-to-end body ends.

46. 46. ​​The method of claim 44 or 45, wherein the anode includes one or more attachment wires for connecting to the one or more metal components, and the end cover covers the one or more attachment wires.

47. 47. A method according to any one of claims 34 to 46, in which two bodies are provided, each containing a respective anode, each of said anodes being connected to the other anode and connected as a group to said one or more metal parts.

48. 48. The method of any one of claims 33 to 47, wherein a mounting alignment member is provided for mounting the body to the concrete structure, the mounting alignment member including at least one mounting foot for aligning and supporting the body to the concrete structure.

49. A method as claimed in any one of claims 33 to 48, wherein the impermeable body includes at least one moisture cavity therein at the exposed surface of the concrete structure for retaining moisture.

50. 1. A method for cathodic protection of one or more metal components within a concrete structure, comprising: attaching to an exposed surface of the concrete structure a preformed body having a front surface for attachment to the exposed surface and a rear surface facing away from the concrete structure; the preformed body including an anode supported thereon; The process and attaching the front surface of the pre-formed body to the concrete structure using an ionically conductive adhesive material; Including, the anode is covered with an impermeable covering disposed to cover the anode and the adhesive material when the front surface is attached to the exposed surface of the concrete structure; The method wherein the impermeable coating extends beyond the anode and the adhesive material on both sides.

51. 51. The method of claim 50, wherein the preformed body includes an ionically conductive support carried thereon and engaging the anode, the support having a front surface positioned to allow ions to be transferred from the anode through the support, into the concrete structure, and to the one or more metal components within the concrete structure.

52. 52. The method of claim 51, wherein the adhesive material is wider than the anode and / or the support material.

53. 53. The method of claim 52, wherein the adhesive material provides a larger area than the anode and / or the support material sealed onto the concrete structure.

54. A method according to any one of claims 50 to 53, wherein the adhesive substance is applied as a layer in a groove defined in the front surface of the support.

55. 55. The method of claim 54, wherein the groove is defined by spaced apart longitudinally extending edges positioned to trap the adhesive substance therebetween.

56. 56. A method according to any one of claims 50 to 55, wherein the impermeable covering has a raised central portion beneath which the support and anode are housed, and two side-depending flange portions for engaging the exposed surface.

57. 57. The method of claim 56, wherein the two side-dependent flange portions include stop beads for containing adhesive and outer cover portions extending outward from the stop beads for covering adhesive that leaks from the stop beads.

58. 58. A method according to any one of claims 50 to 57, wherein the impermeable covering includes a flange that extends into and engages the support to maintain the support, and the anode therein, within the body.

59. 59. A method as claimed in any one of claims 50 to 58, wherein the impermeable covering includes fastener holes at locations thereon through which screw fasteners can pass to engage the concrete structure.

60. A method according to any one of claims 50 to 59, including the step of attaching a separate end cover to the impermeable covering at one end of the body.

61. 61. The method of claim 60, wherein the end cover includes an engagement lip for attachment to the impermeable covering at the one end of the body.

62. 62. The method of claim 61, wherein the end cover bridges the ends of two bodies.

63. 63. The method of claim 61 or 62, wherein the anode includes one or more attachment wires for connecting to the one or more metal components, and the end cover covers the one or more attachment wires.

64. 64. The method of any one of claims 50 to 63, wherein a mounting member is provided for mounting to the concrete structure, the mounting member including at least one mounting foot for attaching and supporting the body to the concrete structure.

65. A method according to any one of claims 50 to 64, wherein the impermeable covering includes at least one receiving cavity therein for receiving a connecting wire associated with the anode.

66. 66. The method of claim 65, wherein the receiving cavity is covered by a cover strip.

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