US20140048975A1 - Corrosion Protection of Cables in a Concrete Structure - Google Patents

Corrosion Protection of Cables in a Concrete Structure Download PDF

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Publication number
US20140048975A1
US20140048975A1 US13/585,180 US201213585180A US2014048975A1 US 20140048975 A1 US20140048975 A1 US 20140048975A1 US 201213585180 A US201213585180 A US 201213585180A US 2014048975 A1 US2014048975 A1 US 2014048975A1
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Prior art keywords
cable
wires
fluid
concrete
covering material
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Abandoned
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US13/585,180
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English (en)
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David Whitmore
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Individual
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Individual
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Priority to US13/585,180 priority Critical patent/US20140048975A1/en
Priority to PCT/CA2013/050604 priority patent/WO2014026279A1/en
Priority to EP13829833.6A priority patent/EP2885452B1/en
Priority to JP2015526843A priority patent/JP6218049B2/ja
Priority to AU2013302266A priority patent/AU2013302266B2/en
Priority to CA2880559A priority patent/CA2880559C/en
Publication of US20140048975A1 publication Critical patent/US20140048975A1/en
Priority to US15/211,466 priority patent/US10077554B2/en
Abandoned legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/015—Anti-corrosion coatings or treating compositions, e.g. containing waterglass or based on another metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
    • B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/10—Coating or impregnating
    • C04B20/1003—Non-compositional aspects of the coating or impregnation
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/10—Coating or impregnating
    • C04B20/1003—Non-compositional aspects of the coating or impregnation
    • C04B20/1014—Coating or impregnating materials characterised by the shape, e.g. fibrous materials
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B7/00—Details of, or auxiliary devices incorporated in, rope- or cable-making machines; Auxiliary apparatus associated with such machines
    • D07B7/02—Machine details; Auxiliary devices
    • D07B7/12—Machine details; Auxiliary devices for softening, lubricating or impregnating ropes, cables, or component strands thereof
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/12—Mounting of reinforcing inserts; Prestressing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00—Investigating materials by mechanical methods
    • G01N19/10—Measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/22—Sheathing; Armouring; Screening; Applying other protective layers
    • H01B13/221—Sheathing; Armouring; Screening; Applying other protective layers filling-up interstices
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20—Resistance against chemical, physical or biological attack
    • C04B2111/26—Corrosion of reinforcement resistance
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2075—Fillers
    • D07B2201/2077—Fillers having an anti-corrosive function
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2205/00—Rope or cable materials
    • D07B2205/20—Organic high polymers
    • D07B2205/2046—Polyamides, e.g. nylons
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2205/00—Rope or cable materials
    • D07B2205/30—Inorganic materials
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2205/00—Rope or cable materials
    • D07B2205/30—Inorganic materials
    • D07B2205/3017—Silicon carbides
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2501/00—Application field
    • D07B2501/20—Application field related to ropes or cables
    • D07B2501/2015—Construction industries
    • D07B2501/2023—Concrete enforcements
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E04C5/10—Ducts

Definitions

  • the present invention relates generally to the field of pre-stressed or post-tensioned concrete structures, and more particularly, to a method for protection of steel cables susceptible to corrosion in such concrete structures.
  • Pre-tensioning of concrete is a method for improving the load carrying capacity of concrete structures. It can be used to produce beams, floors or bridges with longer spans and less deflection using thinner sections than is practical with ordinary reinforced concrete.
  • Tendons used for pre-tensioning are generally made of high tensile steel cables and are used to provide an initial compressive load which produces a compressive stress that balances some or all of the tensile stress that the concrete member would otherwise experience due to a bending load.
  • Pre-tensioning can be accomplished in three ways: pre-stressed concrete, and bonded or un-bonded post-tensioned concrete.
  • Pre-stressed concrete is cast around already tensioned cables. This method produces a good bond between the cable and concrete, which both protects the cable from corrosion and allows for direct transfer of loads between the cable and the concrete.
  • the cured concrete adheres and bonds to the cables and when the load on the cables is released, much of it is transferred to the concrete as compression by static friction. However, it requires stout formwork and anchoring points between which the cable is stretched and held prior to the placement of the concrete.
  • the cables are usually in a straight line unless deviators are installed in which case the cable will typically have straight segments.
  • Most pre-tensioned concrete elements are prefabricated in a factory and must be transported to the construction site, which limits their size. Examples of pre-stressed elements include balcony elements, lintels, floor panels, double tees, beams and foundation piles.
  • Bonded post-tensioned concrete is the descriptive term for a method of applying compression after pouring and curing the concrete.
  • the concrete is typically cast around a duct, which may be of plastic, steel or aluminium.
  • the ducts are often curved or draped to follow the profile where they will provide the greatest structural benefit.
  • One or more cables are generally fished through the duct after the concrete is poured. Once the concrete has hardened, the cables are tensioned by hydraulic jacks that react against the concrete member itself. When the cables have been tensioned sufficiently, they are wedged or clamped in position to maintain tension in the cables and compression in the concrete after the jacks are removed. The duct is then filled with a grout to protect the cables from corrosion.
  • Un-bonded post-tensioned concrete differs from bonded post-tensioning by providing each individual cable permanent freedom of movement relative to the concrete.
  • each individual cable is typically coated with grease and enclosed by a plastic sheathing.
  • the cable is a loose fit inside the sheath with the intention that the grease fills the space between the cable and the sheath.
  • This construction can be formed by inserting the cable from one end into a pre-formed tubular sheath with the space between them being sufficient to allow the insertion to occur.
  • the sheath is formed by covering the cable and surrounding grease with a strip of the covering material which is bent around the cable and then sealed or welded along a longitudinal seam to surround the cable.
  • the cable is coated with grease and is sealed to prevent moisture entry and to ensure that the steel cable is maintained in a moisture free environment.
  • voids are typically present in this type of construction.
  • the cable is covered by grease and a plastic sheath is extruded onto the exterior of the cable as a tight envelope. In this case there are typically no voids and no path around the cable for moisture or other material to migrate along the sheath.
  • the sheath be continuous, complete and moisture impermeable.
  • the sheath is often damaged by its introduction into the forms, by failure to seal the ends of the sheath, or by the tensioning of the cable so that moisture can enter.
  • no moisture can enter into or migrate along the sheath so that no corrosion can occur.
  • corrosion typically does occur even to the extent of causing catastrophic failures if not detected and remediated.
  • WO 87/06958 assigned to Precision Dependability and Quality Testing discloses a method of treating a reinforced structure of masonry or cementitious material, such as concrete, to inhibit corrosion of the reinforcement.
  • the method comprises inserting within the said material a vapour phase corrosion inhibitor so that the inhibitor migrates through the porous structure of the said material, and more-particularly along the interface between the said material and the reinforcement, to protect the reinforcement.
  • This method of the present invention relates to the pre-tensioning system where the cable is intimately surrounded by the concrete itself.
  • This method of the present invention relates to the un-bonded post-tensioning system where the cable is contained within an extruded plastic sleeve extruded onto the cable and extending along the concrete member and there is provided an un-bonded filler material, generally grease, between the cable and the sleeve arranged to allow sliding of the cable within the sleeve during tensioning;
  • This method of the present invention relates to the bonded post-tensioning system where the cable is contained within a tubular container extending along the concrete member and the cable is intimately surrounded by a filler material, generally a cementitious grout, inserted into the tubular container after tensioning of the cable within the tubular container so that the grout is bonded intimately to the wires of the cable.
  • a filler material generally a cementitious grout
  • the cable comprises an array of wires extending along the concrete for providing reinforcement thereto;
  • the cable is intimately surrounded by a covering material which is engaged with a periphery of the cable so that there are insufficient interconnected spaces between the cable and the covering material to allow passage of fluid along the cable between the cable and the covering material;
  • the method comprising inserting a fluid into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable.
  • the present Applicant has found totally surprisingly that even in a situation where there is no path around the cable as required by the above prior art methods, there is a sufficient path within the interstices of the wires of the cable itself, even when under the high loads necessary for tensioning the concrete, to allow effective quantities of a fluid to pass along the cable.
  • the fluid is selected so that it provides properties suitable to reduce corrosion of the steel wires of the cable.
  • the fluid can contain corrosion inhibiting material such as corrosion inhibiting materials selected from the group consisting of:
  • Nitrobenzene and 1-Nitronaphthalene are Nitrobenzene and 1-Nitronaphthalene.
  • the corrosion inhibiting material is Calcium sulfonate or Organofunctional silane.
  • the fluid can contain also or as an alternative Vapor Phase Inhibitors which are provided as a solid or liquid and have the properties of evaporation to provide a material which condenses into required locations to act as a corrosion inhibitor.
  • the carrier fluid can be a liquid or can be a gas. Where a gas is used this can operate as a drying agent to drive off any moisture from the area within or around the cable. Where a liquid is used this is typically a non-water-based liquid so as to avoid adding additional water which may be detrimental to the corrosion process or to drive out moisture by impregnating the volume around the cable with the liquid itself.
  • the liquid or other carrier fluid may be selected to react with any water which may be present. If a water-based liquid is used, sufficient inhibitor or the use of some type of drying or other corrosion mitigation technique is recommended to minimize the risk of accelerating the corrosion of cables which may be contaminated with salt or otherwise already corroding.
  • the liquid can be arranged to expel moisture from the interstitial spaces between the wires of the cable.
  • the liquid can be arranged to generate an impregnated zone which can be hydrophobic at or around the cable by diffusing or spreading outwardly from the cable into the surrounding covering material so as to generate a hydrophobic zone around the cable.
  • the fluid interacts with the covering material to change its properties within the impregnated region.
  • the fluid interacts with the covering material to reduce permeability of the impregnated region.
  • the fluid interacts with the covering material to increase the electrical resistivity of the impregnated region.
  • the fluid forms a protective film on exposed portions of the wires.
  • the liquid is an oil or silicone based material generally of low viscosity which acts to displace any moisture and to fill any interstices where moisture may return thus preventing further corrosion.
  • the liquid may be selected so that it is arranged to increase in viscosity so that it remains more effectively in the location to which it has reached during the insertion process or to set-up to form a solid after inserting into the cable.
  • liquid may be selected from the group consisting of
  • the liquid may also be the corrosion inhibiting material such as organofunctional silane, calcium sulfonate or amino alcohol.
  • the liquid may also be water as described above.
  • the fluid comprises a gas arranged to effect a drying action on the wires of the cable to expel moisture from the interstitial spaces between the wires.
  • a gas arranged to effect a drying action on the wires of the cable to expel moisture from the interstitial spaces between the wires.
  • dry gas may also dry the surrounding covering material over time.
  • the introduction of gas may be used in a testing procedure to drive moisture or moisture-laden air from the interstitial spaces between the wires, which gas is then collected at the second location for analysis of a moisture content thereof. In this way an initial testing procedure can be provided which detects the presence of moisture and then goes onto a remediation process if moisture is detected.
  • the cable comprises an array of wires extending along the concrete for providing reinforcement thereto;
  • the method comprising inserting a fluid into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable.
  • the method is used with pre-stressed cables where the cable is buried into the concrete as the concrete is set.
  • the cable comprises an array of wires extending along the concrete member for providing reinforcement thereto;
  • the cable is contained within a tubular container extending along the concrete member
  • wires of the cable are intimately surrounded by a filler material inserted into the tubular container after tensioning of the cable within the tubular container where the filler material is bonded intimately to the wires of the cable;
  • the method comprising inserting a fluid into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable.
  • the method is used with post tensioned bonded cables where the cable is buried in a grout injected into the tubular sleeve after tensioning.
  • the cable comprises an array of wires confined together to form an elongate cable
  • the cable is contained within an extruded plastic sleeve extruded onto the cable so as to enter into external interstices between the wires around the cable;
  • the method comprising inserting a fluid into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable.
  • the method is used with post tensioned un-bonded cables where the cable is contained within an extruded plastic sleeve.
  • the cable comprises an array of wires confined together to form an elongate cable extending along the concrete for providing reinforcement thereto;
  • the method comprising introducing a liquid into the interstitial spaces within the cable at a first location along the cable and causing the fluid to pass along the cable to a second location along the cable;
  • This impregnated zone may be hydrophobic, it may be impregnated with corrosion inhibiting material, or it may be impregnated to provide high electrical resistance.
  • the impregnation of the covering material may otherwise modify the properties of the covering material such as providing reduced porosity, reduced permeability, waterproofing or increased strength.
  • the injection of the liquid such as oil, amino alcohol, calcium sulfonate or silane has been found to cause the liquid to diffuse or migrate outwardly into a surrounding volume of concrete or mortar surrounding the cable to form a generally cylindrical impregnated zone around the cable.
  • the reaction of the silane with the concrete has created a hydrophobic layer of concrete surrounding the cable into which it is difficult for moisture to penetrate.
  • the injection of the fluid into the cable can occur at ends of the cable where the wires of the cable are exposed so that the injection occurs directly into the interstices between the wires.
  • the second location may be at the other end or may be at an intermediate location.
  • injection of the fluid into the cable can occur at an intermediate location of the cable is also possible where the injection is at the periphery of the cable requiring the fluid to penetrate from the periphery into the interstices between the wires. Both techniques have been shown to operate satisfactorily.
  • the injection typically will require some pressure but this has been found that a relatively low pressure of the order of 50 to 100 psi for low viscosity liquids are suitable to travel the length of the cable, coat the exposed steel surfaces, impregnate the concrete surrounding the cable, drive off moisture and carry the corrosion inhibitor. Higher pressures may be required for longer lengths, higher viscosity liquids or semi-liquid materials such as grease.
  • Vacuum can be used at the downstream end either in addition to or as a replacement to the pressurized supply. Gas can be injected in the same manner either as air for drying or as a vapor for vapor deposition of Vapor Phase Corrosion inhibitors.
  • the ends or intermediate locations may be already exposed or may be located by drilling to the cable or by other excavation methods. Intermediate locations may be excavated to expose one face of the cable or the excavation may extend around the periphery of the cable.
  • inhibitors may be used in the method of the invention, provided they are chemically suited to inhibiting corrosion of whatever reinforcement is used.
  • the inhibitor for ferrous metal reinforcement may for example be, or include, at least one material selected from
  • the corrosion inhibitor can be in liquid form or may be a Vapor Phase Inhibitor (VPI).
  • VPI's for protecting ferrous metal (usually steel) reinforcement by the method of the present invention are dicyclohexylamine nitrite (DCHN), cyclohexylamine benzoate (CHAB) and cyclohexylamine carbamate (CHC), more preferably a mixture of CHAB and CHC. These are both white solids and have the following structures: CHAB O—NH3+02C CHC NH3+O—C—NH—0 Mixtures of fast-acting and slow-acting VPI's have the advantage of combining fast initial action with extended service life.
  • the inhibitor preferably comprises at least two vapour phase inhibitor compounds, at least one of which vaporises relatively slowly and at least one other of which vaporises relatively quickly under the conditions to be encountered by the concrete structure in service.
  • FIG. 1 is a vertical cross-sectional view transversely through a concrete member at an injection site for a fluid into the interstices of a reinforcing pre-stressed cable in a method according to the present invention.
  • FIG. 2 is a vertical cross-sectional view longitudinally through a concrete member at a bonded post-tensioned reinforcing cable showing fluid injection into ends of the cable in a method according to the present invention.
  • FIG. 3 is a cross-sectional view through the cable and surrounding sleeve of the concrete member of FIG. 2 ,
  • FIG. 4 is a cross-sectional view through an un-bonded post-tensioned cable with surrounding plastic sleeves showing the interstices of the cable containing the injected fluid.
  • FIG. 1 a pre-stressed steel reinforcing cable 10 embedded in a concrete member 11 .
  • the cable 10 comprises an array of wires 12 confined together and under tension.
  • the wires are wound around a helix at a shallow angle so as to hold them as a confined array with each wire butting against its neighbours and held in contact with its neighbours by the loads therebetween generated by the tension on the helical array.
  • each wire has its surface in direct contact with its neighbour along its length as indicated at 13.
  • the cable is intimately surrounded by the concrete itself by casting of the concrete while the cable is in place in the form so that the concrete is engaged with a periphery of the cable at the peripheral surface of the outermost wires.
  • the concrete in the casting process butts intimately with all of the peripheral surfaces of the wires and prevents the formation of any spaces around the cable to allow passage of fluid longitudinally along the cable in spaces between the cable and the covering material.
  • the method of the present invention therefore comprises inserting a fluid 16 into the interstitial spaces 15 between the wires of the cable.
  • the fluid is injected or inserted at a first location along the cable and the fluid is caused to pass through the interstitial spaces between the wires of the cable to a second location along the cable.
  • the location in FIG. 1 is at a position along the length of the cable so that a hole 17 is drilled to intersect the cable from a surface 18 of the concrete member to the cable so that one side face of the cable is exposed in the hole.
  • a tube 19 is inserted into the hole and held in place by an adhesive or by a suitable coupling 20 which holds the tube in place to resist the pressure in the fluid tending to displace the tube.
  • the hole may be excavated and may extend around the periphery of the cable at the location of the excavation.
  • Many different mounting arrangements can be used and one example only is shown where a flange 21 is fastened to the surface 18 by screws 22 .
  • the fluid 16 is provided by a pressurized container 23 which is attached to the tube.
  • the container can be of any arrangement depending on the pressure to be applied. In one example the pressure is of the order of 50 to 100 psi which requires only a plastic container with a hand pump for generating the pressure. In other cases a pressure pump, pressure pot, piston pump, gear pump, hydraulic cylinder or compressor may be used to generate the required fluid pressure to enable the material to flow. Depending on the type of pumping and associated measuring devices, the applied pressure and flow rate can be adjusted and monitored. Intermediate holes can be provided to monitor the movement of the fluid along the length of the cable or to progressively insert the fluid into the cable, section by section to minimize the distance the fluid is required to flow from each injection location. Vacuum may be applied at a position separate from the point of application of the fluid to assist in flow and penetration of the fluid along the length of the cable.
  • the fluid 16 at the side face of the cable can penetrate between the wires into the interstices 15 into the interstices of the wires within the cable itself. From those interstices the fluid can pass along the cable to a second location.
  • the second location not shown in FIG. 1 can be at an end of the cable or can be at another intermediate location on the cable. In order to complete protection of a long length of cable, a number of locations along the cable can be selected and fluid injected to pass along the cable to a next location.
  • the fluid 16 is selected as defined above so that it includes a carrier as defined and a corrosion inhibitor as defined which provides properties suitable to reduce corrosion of the steel wires of the cable.
  • the corrosion inhibitor may improve the durability of the structure by improving or modifying the properties of the surrounding concrete.
  • the carrier and the corrosion inhibitor may in some cases be the same material.
  • the fluid includes a liquid carrier which may expel moisture or react with moisture from the interstitial spaces 15 between the wires of the cable and impregnate the surrounding concrete to generate a hydrophobic zone 24 around the cable by diffusing or spreading outwardly from the cable into the surrounding concrete.
  • the fluid may also act to coat the wires and form a protective film on the surface of the wires.
  • the interior wire surfaces may be largely or fully coated.
  • the exterior wire surfaces in direct contact with the surrounding concrete and may receive only a partial protective film coating.
  • the use of a fluid which acts to coat the wires and form a protective film is particularly beneficial to provide corrosion protection to steel wire surfaces which are exposed to air bubbles, voids or pockets in the surrounding concrete, grout or filler material at certain points along the length of the cable. The fluid can reach these bubbles, voids or pockets via the interstitial spaces even though they are not interconnected through the covering material.
  • the injection of the carrier liquid such as oil, amine, amino alcohol, calcium sulfonate, silane, siloxane, silicone, organic solvent or other polymer causes the liquid to diffuse or migrate outwardly to impregnate into a surrounding volume of concrete or mortar surrounding the cable to form a generally cylindrical impregnated zone around the cable.
  • the fluid may be free of water.
  • the fluid can be selected so that it interacts with the covering material to change the properties of the covering material within the impregnated region.
  • the fluid interacts with the covering material to reduce permeability of the impregnated region.
  • the fluid interacts with the covering material to increase the electrical resistivity of the impregnated region.
  • the fluid forms a protective film on exposed portions of the wires.
  • the impregnated zone around the cable includes a corrosion inhibiting material.
  • the impregnated zone around the cable has an increased electrical resistance.
  • the impregnated zone around the cable has a reduced permeability.
  • the method is used with a post-tensioned system in which the cable 30 formed by wires 30 A with interstices 30 B is contained within a tubular container 31 extending along the concrete member 32 between the ends 34 , 35 .
  • the wires of the cable are intimately surrounded by a filler material or grout 33 inserted into the tubular container 31 after tensioning of the cable 30 within the tubular container so that the filler material 33 is bonded intimately to the wires of the cable 30 .
  • multiple cables are present inside a singular tubular container (duct) wherein the filler material surrounds each of the cables.
  • the duct assembly containing multiple cables is often referred to as a tendon or multi-strand assembly.
  • the method comprising inserting a fluid into interstitial spaces 30 B between the wires of the cable at a first location at the end 35 along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location at the end 34 along the cable.
  • the fluid comprises a gas from a pressurized supply 36 arranged to effect a drying action on the wires of the cable to expel moisture from the interstitial spaces between the wires.
  • the gas may be used in a testing procedure to drive moisture from the interstitial spaces between the wires, which is then collected at the end 34 (or an alternate location) at a sample extractor 37 at an outlet 40 for analysis of a moisture content.
  • an initial testing procedure can be provided which detects the presence of any moisture and then goes onto a remediation process if moisture is detected.
  • a vacuum pump 38 can be provided connected to the outlet 40 to assist in drawing the gas more effectively along the path.
  • a valve 39 controls the connection of the outlet 40 to the sample collector 37 or to the vacuum 38 .
  • liquid can be injected into the interstices and can provide benefits similar to the example previously described.
  • the cable 40 comprises an array of wires 41 confined together to form an elongate cable with interstices 42 where the cable 40 is contained within an extruded plastic sleeve 43 extruded onto the cable.
  • an un-bonded filler material typically grease 44 , between the cable 40 and the sleeve 43 arranged to allow sliding of the cable within the sleeve during tensioning.
  • the fluid is injected into interstitial spaces 42 between the wires of the cable 41 at a first location along the cable and the fluid passes through the interstitial spaces between the wires of the cable to a second location along the cable.

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US13/585,180 2012-08-14 2012-08-14 Corrosion Protection of Cables in a Concrete Structure Abandoned US20140048975A1 (en)

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US13/585,180 US20140048975A1 (en) 2012-08-14 2012-08-14 Corrosion Protection of Cables in a Concrete Structure
PCT/CA2013/050604 WO2014026279A1 (en) 2012-08-14 2013-08-06 Corrosion protection of cables in a concrete structure
EP13829833.6A EP2885452B1 (en) 2012-08-14 2013-08-06 Corrosion protection of cables in a concrete structure
JP2015526843A JP6218049B2 (ja) 2012-08-14 2013-08-06 コンクリート構造物中のケーブルの腐食防止
AU2013302266A AU2013302266B2 (en) 2012-08-14 2013-08-06 Corrosion protection of cables in a concrete structure
CA2880559A CA2880559C (en) 2012-08-14 2013-08-06 Corrosion protection of cables in a concrete structure
US15/211,466 US10077554B2 (en) 2012-08-14 2016-07-15 Corrosion protection of cables in a concrete structure

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US13/585,180 US20140048975A1 (en) 2012-08-14 2012-08-14 Corrosion Protection of Cables in a Concrete Structure

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CN108189221A (zh) * 2018-01-25 2018-06-22 华北水利水电大学 再生透水混凝土试块内增强方法及制作该试块的模具
US20230151611A1 (en) * 2020-03-24 2023-05-18 Nv Bekaert Sa Post-tensioned concrete slab with fibres

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CN105088952A (zh) * 2014-05-13 2015-11-25 柳州欧维姆机械股份有限公司 钢绞线外层涂覆有聚脲防护材料的钢绞线拉索及其制作方法
CN109827894B (zh) * 2019-02-28 2021-11-02 国网天津市电力公司电力科学研究院 一种高压电缆封铅进水腐蚀检测方法及装置
RU2709992C1 (ru) * 2019-09-05 2019-12-23 Общество с ограниченной ответственностью "КАБЕЛЬЭЛЕКТРОСВЯЗЬ" Машина для изготовления длинномерных витых изделий, устройство для введения и/или нанесения наполнителя в/на длинномерное витое изделие для этой машины и распределитель для этого устройства
CN112709087B (zh) * 2020-12-22 2022-02-18 江阴凯博钢绳制品有限公司 海工用高强度抗拉不锈钢丝绳的合绳装置

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US20230151611A1 (en) * 2020-03-24 2023-05-18 Nv Bekaert Sa Post-tensioned concrete slab with fibres

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CA2880559C (en) 2018-06-19
JP2015533929A (ja) 2015-11-26
CA2880559A1 (en) 2014-02-20
US10077554B2 (en) 2018-09-18
EP2885452A1 (en) 2015-06-24
JP6218049B2 (ja) 2017-10-25
US20170096817A1 (en) 2017-04-06
EP2885452A4 (en) 2016-05-11
AU2013302266B2 (en) 2017-07-20
WO2014026279A1 (en) 2014-02-20
AU2013302266A1 (en) 2015-02-26

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