AU2009200319A1

AU2009200319A1 - Coated reinforcing elements

Info

Publication number: AU2009200319A1
Application number: AU2009200319A
Authority: AU
Inventors: Murray Corchrane; Adam Morgan
Original assignee: GLASSMETAL IND Pty Ltd
Current assignee: GLASSMETAL INDUSTRIES Pty Ltd
Priority date: 2009-01-29
Filing date: 2009-01-29
Publication date: 2010-08-12

Description

AUSTRALIA Patents Act COMPLETE SPECIFICATION (ORIGINAL) Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Glassmetal Industries Pty Ltd Actual Inventor(s): Adam Morgan, Murray Corchrane Address for Service and Correspondence: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: COATED REINFORCING ELEMENTS Our Ref: 847095 POF Code: 490388/490388 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): WONq 2 COATED REINFORCING ELEMENTS Field of the Invention 5 The present invention generally relates to coated reinforcing elements and a method of producing the same. The invention is particularly applicable for metallic concrete reinforcing elements and it will be convenient to hereinafter disclose the invention in relation to that exemplary application. However, it is to be appreciated that the invention is not limited to that application and may be used with other compatible 10 materials. Background of the Invention The following discussion of the background to the invention is intended to facilitate an 15 understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application. 20 Concrete is formed from a hydrated mixture of a cementitous material, typically Portland cement and a stone aggregate. Concrete mixes have high resistance to compressive stresses but comparatively low tensile strength. Metal reinforcement, such as steel, can therefore be used to provide tensile strength to concrete. The composite material is commonly known as reinforced concrete. 25 However, metal embedded in concrete can bond poorly with the contacting cementitous material due to poor coupling interaction between the constituent cementitous material of the concrete and the metal. 30 International Patent Publication W02007/038518 teaches one method of forming a stronger bond between the concrete matrix and imbedded metal reinforcing elements by forming a composite enamel-refractory coating on the metal reinforcing element prior to insertion into the cement mortar used to form the concrete. The coating comprises a glass frit mixed with a refractory material, such as dry portland cement, X:\ECP'Patent Spedflcatons\ProvisionasCoated Conrete RenorC oa1d Concrete ReinforCement - complete doc 3 which is bonded, typically by heat, to the surface of the reinforcing element. The enamel-refractory coating produces a strong bond between the metal reinforcement and its concrete or mortar matrix. 5 The applicant has found that this enamel-refractory coating can have adhesion problems when directly applied to a metal surface. It would therefore be desirable to provide an alternative enamel-refractory coating for metal reinforcing elements. Summary of the Invention 10 According to a first aspect of the present invention, there is provided a method of producing a coated reinforcing material, comprising: coating a reinforcing material with at least one coating of an enamel coating material; 15 heating the enamel coating material and the reinforcing material to a temperature that forms an enamel coating that substantially bonds to the reinforcing material; cooling the coated reinforcing material; coating the coated reinforcing material with at least one coating of a further 20 coating material comprising a mixture of cementitous material and glass flux; and heating the further coating material and the coated reinforcing material to a temperature which forms a bond between the further coating material and the enamel coating and/or the reinforcing material. 25 The method of the present invention applies two different coatings to a reinforcing material. The application of an enamel ground coat in the first coating step provides a surface onto which the further coating material can bond and is also preferably physically bonded to the reinforcing material. The glass flux in the further coating material assists in bonding this coating material to the enamel coating on the 30 reinforcing material. The cementitous material content of the further coating material has been found to improve the bonding of a variety of cementitous-based mortars or concretes to a variety of metals, such as steel, stainless steel, aluminium, copper and the like, or items plated with these metals. This coating increases the strength of the bond between the reinforcing element and a concrete matrix in which the coated X:\ECP\PateM Spedfications\PrLsionas\Coated Concrete ReinfordingCostod Concrete Reinforcenent - ow npleta.doc 4 reinforcing element is imbedded as compared to uncoated (unglazed) reinforcing elements imbedded in an equivalent concrete matrix. For the purposes of the present invention, a cementitious material is generally any 5 material having cementing properties such as portland cement, blended hydraulic cement, fly ash, ground granulated blast furnace slag, silica fume, calcined clay, metakaolin, calcined shale, rice husk ash, mica, quartz, aluminium silicate, other refractory inorganic compounds and geopolymer materials such as aluminosilicate materials, mineral polymers, ceramic and refractory materials, and concrete materials. 10 In some embodiments, the cementitous material can include and/or substantially comprise one or more refractory materials. A refractory material is to be understood to comprise a material that does not melt at temperatures that fuse frits used in making the enamel and further coating materials in some embodiments of the present invention. 15 The reinforcing material is initially coated with a ground or base coat of enamel coating material. One or several coats of this base coat can be applied to the reinforcing material to substantially completely coat the exterior surface of the reinforcing material with an enamel coating. A complete enamel coating affords 20 substantial corrosion resistance to the reinforcing material prior to immersion in a concrete matrix and when immersed in the concrete matrix. The enamel coating material could comprise any suitable material capable of forming an enamel coating such as an enamel slip. The slip preferably includes frits suitable for forming a ground coat on the selected reinforcing material. Where an enamel slip is used, the 25 enamel slip can comprises a paste which includes frits, water, clay and other suspending agents. The heating step in the method melts the glass material in the enamel coating material and the further coating material. The heating temperatures are preferably 30 selected to cause the glass material in the enamel coating material to physically bond to the reinforcing material in the first heating step and the further coating material to physically bond to the enamel coating in the second heating step. In the first heating step the enamel coating material and the reinforcing material is therefore preferably heated to between 700 and 1000*C, more preferably between 800 and 900 0 C, and X\ECP\Patent Spedficatons\Proviionals\Coated Concrete ReInfor:ing\Costed Concrete Renforcement - comipete.doc 5 most preferably at least about 8500C to form a bond between the enamel coating material and the reinforcing material. Similarly, the further coating material and the coated reinforcing material is preferably heated to between 700 and 1000 0 C, more preferably between 800 and 900*C, and most preferably at least about 8500C to form 5 a bond between the coating mixture and the enamel coating and/or reinforcing material. In some embodiments, this heating step can also form a substantially glazed coating of the further coating material on the coated reinforcing material. The heating steps are preferably conducted for a heating period of between two minutes to 60 minutes, more preferably between 20 minutes to 45 minutes, and most 10 preferably at least 30 minutes. These times are dependent on the thickness of the metal substrate. For example, in one embodiment, one or both of the reinforcing material and coating material/mixture is heated to about 8600C for at least 30 minutes. 15 The heated enamel coated reinforcing material is cooled to a temperature which allows safe handling of the reinforcing material prior to applying the further coating material. In most cases, the enamel coated reinforcing material is cooled to around ambient temperature. Nevertheless, in some embodiments it may be possible to apply the further coat at higher temperatures and therefore cool the enamel coated 20 reinforcing material to a higher final cooling temperature. The heated enamel coated reinforcing material can be cooled by a number of means including convection cooling such as forced air, hot dipping in liquid such as water or air cooling in ambient air. Like the enamel coating material, it may be preferable to apply the further coating 25 material to the coated reinforcing material two or more times to build up a thicker or more complete coating over the enamel coating(s). Application of at least another coating of the further coating material would entail repeating at least once the steps of: coating the reinforcing material with a coating of the further coating material; and heating the further coating material and the coated reinforcing material to a 30 temperature which forms a bond between the further coating material and the underlying surface of the reinforcing material. The underlying surface would generally be the previous coat of further coating material. However, where this coat is incomplete it may comprise the enamel coating and/or the uncoated exterior surface of the reinforcing material. X\ECPPatent SpecifltiP, on a1sCoaed Concrete Reinforcing\Coated Concrete Reinforcernont - cornplete.doc 6 The enamel coating material and further coating material can be applied using any suitable coating application means. In one embodiment, the enamel coating and/or further coating material is applied to the reinforcing material using a cold spraying 5 process. In most embodiments of these coating materials include a glass frit composition which can be applied to the reinforcing material as a dry or wet state. Techniques suitable for applying dry and/or wet coatings materials include spraying, dipping, brushing, flowing on, electrostatic spraying, rolling, or dusting through a sieve. For example, in some embodiments the further coating material is applied to 10 the reinforcing element by electrostatic dry particle/powder coat. In other embodiments, the frit and refractory material are suspended in a liquid carrier, such as water. However, the applicants preferably coat the reinforcing material with at least one coat of the further coating material by applying an oil coating onto the coated reinforcing material and then applying the further coating material. The oil is 15 used as a carrier to adhere the dry further coating material to the enamel coated reinforcing material prior to heating of the further coated reinforcing material. Here, the enamel coated reinforcing material is dipped in an oil bath and then rolled in the further coating material. Any oil with sufficient viscous properties to adhere the dry further coating material mixture to the enamel coated reinforcing material could be 20 used. Preferably, the oil dissipates, evaporates or is otherwise substantially removed from the coating material during the heating process. One suitable type of oil is a printing oil such as pine oil. Other types of organic (non silicone based) high viscosity oils could also be used. 25 The reinforcing material is preferably pre-treated prior to the application of the first enamel coating to clean the surface of the reinforcing material. The pre-treatment regime typically includes cleaning and degreasing the surfaces of the reinforcing material. This pre-treatment step can be achieved using a sand blasting process. However, it is preferably achieved by pickling the reinforcing material to substantially 30 remove surface impurities from the material. In some embodiments, the surface of the reinforcing material is etched with hydrochloric acid after degreasing. However, it is to be appreciated that this etching step is only an optional step. X:\ECP\Patent SpedicabosPrvitsionals\Coated Concrete ReInforitg\Coated Conrete Reinforcement - omplete.doc 7 In one particular embodiment, the pre-treatment regime includes the steps of: cleaning the reinforcing material with an alkaline cleaner; rinsing with water; pickling the reinforcing material in a dilute hydrochloric acid solution; and neutralising with a suitable fluid solution having a pH at or above 7.0. 5 The reinforcing material coated with the coating according to the present invention can be any material that can be immersed in a cementitous matrix such as concrete to reinforce that cementitous material. The reinforcing material can therefore be for example metal fibres, metal rods, steel fibres, steel rods, metal alloy fibres, metal 10 alloy rods, metal, metal alloys, steel, stainless steel, aluminium, copper, deformed metal bars, mesh, fabricated ligatures or material plated with metal. Any suitable glass frit can be used for the first and second coatings. For the enamel coating, it is preferable for the selected frit to be able to bond directly to the reinforcing 15 material. For example, where the reinforcing material is steel, the frit can contain a transition metal, such as nickel, cobalt. A suitable bonding frit for steel is a ground coat enamel that can bond directly to the steel. The glass flux of the further coating material preferably includes a frit capable of forming a bond with the underlying enamel coat. This frit may be a different frit to that used in the enamel coating 20 material, but is preferably the same or a similar frit to that used in the enamel coating material. Suitable frits include a ground glass, a ground glass slag, a frit suspended in a liquid, a glass frit suspended in a liquid, a frit suspended in a liquid incorporating a thickener, a powdered frit, a powdered glass frit, a frit containing transition metals, a frit containing cobalt, a frit containing nickel, an alkali resistant glass frit, an alkali and 25 acid resistant glass frit and combinations thereof. Cementitous materials generally exist as a strong alkaline paste prior to hardening and curing. This paste varies in pH from about 12 to almost 14 depending on the constituents. The selected frits are therefore preferably alkali-resistant to be un 30 reactive to this alkaline environment. More preferably, at least one of the enamel coating material of the first coating step or glass flux of the second coating step includes an acid and alkaline resistant frit. Suitable frits of this type are available from Ferro Corporation, Ohio USA. X:\ECP\Patent Spedfcatons\ProvsionaLsCated Conaee ReWordcing ated Concrete Reinforcement - complete.doc 8 The further coating material comprises a mixture of mainly cementitous material and glass flux. However, the further coating material may include other constituents such as binders, conditioners, thickeners or the like. Preferably, the further coating material comprises a mixture of a volume amount of between 40 to 70% cementitous 5 material and between 60 to 30% glass flux. In one embodiment the further coating material comprises about equal volume amounts of the glass flux and cementitous material. For example, in one embodiment the further coating material comprises a mixture of dry type I-Il Portland cement in a proportion of up to about 70% by volume and a powdered glass frit. In other embodiments of the present invention, the coating 10 (glaze) may comprise equal amounts by volume of a liquid suspension of an acid and alkali resistant glass frit and a type 1-11 Portland cement. According to a second aspect of the present invention, there is provided a coated reinforcing material comprising: 15 a base reinforcing material having an exterior surface; at least one enamel coating substantially coating the exterior surface of the base reinforcing material; and at least one further coating applied over the enamel coating comprising a mixture of cementitous material and glass flux. 20 Again, the base reinforcing material can be any one of metal fibres, metal rods, steel fibres, steel rods, metal alloy fibres, metal alloy rods, metal, metal alloys, steel, stainless steel, aluminium, copper, material plated with metal, rebar, or combinations thereof. Steel is typically used to reinforce concrete structures. In these instances, 25 the steels could include low-carbon steel, decarburized steel, interstitial-free steel, i.e., steels in which carbon and nitrogen are contained in an alloying element such as titanium, niobium, vanadium and the like, titanium-stabilized steel, or combinations thereof. 30 Again, the enamel coating and the further coating preferably comprise frits, more preferably an acid and alkaline resistant frit as discussed above. X:\ECP\Pater Spedfcatons\ProvtsionalsXCoated Concret RenforcngCoated Concre ReInforcemr - ompetedoc 9 The coated reinforcing material according to the second aspect of the present invention is preferably formed using a method according to the first aspect of the present invention. 5 According to a yet another aspect of the present invention, there is provided a method of producing a coated reinforcing material, comprising: applying an oil to an exterior surface of a reinforcing material; coating the oil coated reinforcing material with at least one coating material comprising a mixture of cementitous material and glass flux; and 10 heating the coating material and the reinforcing material to a temperature which forms a bond between the coating material and the reinforcing material. As discussed previously, the oil is used as a carrier to adhere the dry mixture to the reinforcing material prior to heating the coating material and the reinforcing material. 15 Here, the reinforcing material is coated in oil and then a mixture of cementitous material and glass flux is applied. Any oil with sufficient viscous properties to adhere the dry mixture to the reinforcing material could be used. Preferably, the oil dissipates, evaporates or is otherwise substantially removed from the coating material during the heating process. One suitable type of oil is a printing oil such as pine oil. 20 Other types of organic (non silicone based) high viscosity oils could also be used. Non-silicone based oils are completely vaporised when the coating material and the reinforcing material are heated. Brief Description of the Drawings 25 The present invention will now be described with reference to the figures of the accompanying drawings, which illustrate particular preferred embodiments of the present invention, wherein: 30 Figure 1 is a photograph of a coated metal rod produced using one embodiment of the process of the present invention. XECP\Paten Spedfic ato Prvsonals\Coated Concrete Reinforcing\Coted Concrete Reinforcemnt . wmplete.doc 10 Figure 2 is a more detailed view of the coated metal rod shown in Figure 1, showing the metal rod, an enamel coating and a further composite coating of the coated metal rod. 5 Detailed Description Figures 1 and 2 show a reinforcing steel bar 10 according to one embodiment of the present invention. The illustrated reinforcing steel bar 10 is intended to be illustrative of the type of reinforcing material that could be coated in accordance with the coating 10 method of the present invention. The reinforcing material used could be any one of a variety of reinforcing materials including bars, beams, mesh, wire, fibres, poles, posts, rebar or similar and could have any shape and configuration desired for reinforcing a selected cementitous based concrete element or structure. 15 As best shown in Figure 2, the reinforcing steel bar 10 has three distinct sections exposed along its length. These sections have been presented on this bar 10 for illustrative purposes only. It should be understood that in practice that each of the coatings 14 and 16 would substantially coat the exterior surfacer of the selected reinforcing material. 20 Referring firstly to a ring end of the bar 10 shown in Figure 2, there is shown an uncoated section 12 of the bar 10 providing a view of the uncoated exterior surface of the steel bar 10. This uncoated section 12 of the bar 10 generally has poor bonding characteristics with cementitous materials. 25 Further along the length of the bar 10 is an enamel coated section 14 showing a section of the reinforcing steel bar 10 coated with an enamel ground coat 15. This enamel ground coat 15 is formed from an enamel slip that includes an alkali and acid resistant glass frit which is fired onto the reinforcing steel bar 10. The enamel ground 30 coat 15 forms a generally smooth and shiny glazed enamel coating which is bonded to the underlying exterior surface of the reinforcing steel bar 10. A complete coating of the enamel ground coat 15 over the exterior surface of the reinforcing steel bar 10 provides a corrosion resistance coating over the bar 10. X:\ECP\Paten Specfcatons\rovonals\Coated Concrete ReiforcingCoated Concrete Reinforcement - omplete.doc 11 Yet further along the length of the bar 10 is a further coated section 16 comprising a coating 17 formed from a mixture of vitreous enamel and portland cement which is fired onto the reinforcing steel bar. As shown in Figure 2, the further coating 17 forms a rough or "bumpy" enamelled surface after firing. The enamel content of the coating 5 17 is used to bind the coating 17 together and form a bond with the underlying enamel ground coat 15. The portland cement content of the coating 17 is used to increase the bond between the reinforcing bar 10 and a cementitous/concrete matrix in which the bar 10 can be immersed when used as a reinforcing material for that concrete matrix. 10 Similar coated reinforcing steel bars 10 can be imbedded in a cementitous mortar, such as concrete, as metal reinforcement to provide tensile strength to that concrete. The grains of portland cement in the further coating 17 (or any suitable cementitous material mixed therein) is physically bonded to the reinforcing bar 10 through the 15 vitreous enamel and is also physically bonded the surrounding concrete matrix through the normal cement hardening and curing reactions after the coated reinforcing bar 10 is immersed in that concrete matrix. While not wishing to be limited by any one theory, these bulk materials are bound in the surface of the glass frits, in turn bonding tightly to the calcium silicate hydrate that forms as the portland cement 20 in the concrete hydrates. Thus the bond achieved significantly improves the material properties of reinforced concrete structures such as roadways, bridge decks, foundations, bunkers or the like. The coated reinforcing steel bar 10 shown in Figures 1 and 2 are formed using the 25 following method: Firstly, the steel reinforcing material such a reinforcing steel bar 10 are cleaned of surface impurities and degreased. This involves a pickling process in which the reinforcing material is dipped or sprayed with an alkaline cleaner, rinsed with water, 30 pickled in a cold hydrochloric acid solution, and then neutralize with a suitable liquid solution having a pH of between 7 to 8. The reinforcing material is then dried in an furnace or other suitable heating chamber at 93 to 150 0 C. The cleaned bar could undergo an additional etching step using hydrochloric acid. X-\ECP\Patent Spcfication\PolsIonals\Coated Concrt Reinforcng\Coated Conaete Reinfor en - omplete.doc 12 The cleaned reinforcing material is then immersed in an enamel slip that has been made into a paste by adding water, clay and other suspending agents. The enamel slip used to coat the illustrated reinforcing bar 10 includes an acid and alkaline resistant high temperature frit available from Ferro Corporation, Ohio USA. It should 5 be appreciated that the composition of glass frits for use on reinforcing steel can vary with the manufacturer and the exact compositions are proprietary. For the illustrated reinforcing steel bar 10, the Ferro Frits from Ferro Corporation used for the coating include EGF2148 and EGF2149. The coated reinforcing material is heated to 8600C for 30 minutes in a preheated fired furnace to form a glazed coating 15 that bonds 10 with the exterior surface of the reinforcing material. The coated reinforcing material is then removed from the furnace and allowed to air cool to ambient temperature. It should be appreciated that other enamel coating process could also be used, for example cold spraying of the enamel material onto the reinforcing bar 10. 15 This enamel coating process can be repeated, if necessary, to build a complete coverage of the enamel coat on the reinforcing material. A complete glazed enamel coating provides a corrosion resistance coating to the reinforcing material. The further coating material is then applied to the enamel coated reinforcing material 20 by applying printing oil such as pine oil to the exterior surface of the cooled ground coated reinforcing material, and then covering the oil coated material in a mixture of dry portland cement and glass flux. The further coating material comprises a mixture of equal volumes of glass flux and Portland cement. However, the ratio of glass flux and Portland cement in the mixture can vary. The glass flux used in the further 25 coating material of the further coating 17 of the illustrated reinforcing bar 10 includes an acid and alkaline resistant high temperature frit available from Ferro Corporation, Ohio USA. In this case the further coating material is applied by dipping the enamel coated reinforcing bar 10 into a reservoir of printing oil/pine oil and then rolling the oil coated bar 10 in a tray or other receptacle containing a dry mixture of the Portland 30 cement and glass flux. However, it should be understood that further coating can be applied by other application methods such as though the application of a water based slurry of the glass flux and portland cement by dipping, spraying, brushing, rolling or flow coating the slurry onto the surface of the bar 10. The further coated reinforcing material is heated to 8600C for 30 minutes in a preheated fired furnace to form a X:\ECP\Patent SpodfcaionsPrvisona s\Coted Concrete Reinfordng\Coated Concrete Reinforcement - omplete.doc 13 rough or "bumpy" enamelled surface that is bonded to the exterior surface of the glazed enamel ground coat 15. The further coated reinforcing material is then removed from the furnace and allowed to air cool to ambient temperature. 5 This further coating process can be repeated, if necessary, to build a complete coverage of the further coating material on the reinforcing material. The coated reinforcing material can then be imbedded into a cementitous mortar, such as concrete, to reinforce that concrete. In this respect, the resultant coating on 10 the reinforcing material, such as reinforcing steel bar 10 is compatible with an embedding cementitous matrix, such as a portland cement-based mortar, in which the coated reinforcing material is to be inserted. In addition to improving the bond between the base reinforcing material and the cementitous matrix, the coating may substantially eliminate or reduce the rate of corrosion of metal or metal-plated 15 reinforcement coated with it. In some forms, the method may be used to strongly bond two pieces of material each incorporating a rough (bumpy) enamelled surface, prepared in accordance with embodiments of the present invention, at the interface to be joined. The two pieces 20 may be joined by applying a suitable matrix, such as a portland cement-based grout, as an adhesive. Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It 25 is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention. Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the 30 presence of the stated features, integers, steps or components, but not precluding the presence of one or more other feature, integer, step, component or group thereof. X:\ECP\Patent SpedflcatonProvisionaIs\Coated Concete Reinfordng\Coated Concrete Reirforcement - omplete.doc

Claims

1. A method of producing a coated reinforcing material, comprising: coating a reinforcing material with at least one coating of an enamel coating 5 material; heating the enamel coating material and the reinforcing material to a temperature that forms an enamel coating that substantially bonds to the reinforcing material; cooling the coated reinforcing material; 10 coating the coated reinforcing material with at least one further coating material comprising a mixture of cementitous material and glass flux; and heating the further coating material and the coated reinforcing material to a temperature which forms a bond between the further coating material and/or the reinforcing material. 15

2. A method according to claim 1, wherein in the first heating step the enamel coating material and the reinforcing material is heated to between 700 and 1000*C to form a bond between the enamel coating material and the reinforcing material. 20

3. A method according to claim 1 or 2, wherein the further coating material and the coated reinforcing material is heated to between 700 and 1000"C to form a bond between the further coating material and the enamel coating and/or reinforcing material. 25

4. A method according to any preceding claim, wherein the heating process in one or both of the heating steps is undertake for a period of between two minutes to 45 minutes.

5. A method according to any preceding claim, wherein the reinforcing bar and 30 coating material/mixture in one or both of the heating steps is heated to about 860 0 C for at least 30 minutes. X:\ECPPaten Spedfications Provisionals\Coated Concrete Reinfordng\Coated Concrete Reinforemnent - ompletedoc 15

6. A method according to any preceding claim, wherein the coating reinforcing material is cooled by allowing the heated reinforcing material to cool to a desired temperature in ambient air. 5

7. A method according to any preceding claim, further comprising repeating at least once the steps of: coating the reinforcing material with the further coating material; and heating the further coating material and the coated reinforcing material to a temperature which forms a bond between the further coating material and the 10 underlying surface of the reinforcing material.

8. A method according to any preceding claim, wherein the heating step of heating the further coating material and the coated reinforcing material to a temperature forms a substantially glazed coating of the further coating material on the 15 coated reinforcing material.

9. A method according to any preceding claim, wherein each of the enamel and further coating materials are applied using at least one of spraying, dipping, brushing, flowing on, electrostatic spraying, rolling, or dusting through a sieve. 20

10. A method according to any preceding claim, wherein the further coating material(s) is applied to the reinforcing material by applying an oil coating to the coated reinforcing material and then applying the mixture of cementitous material and glass flux. 25

11. A method according to any claim 10, wherein the oil comprises printing oil.

12. A method according to claim 10 or 11, wherein the oil covered reinforcing material is rolled in the mixture of cementitous material and glass flux. 30

13. A method according to any preceding claim, wherein the reinforcing material is pre-treated to clean the reinforcing material. X\ECP'Patent Spedfications\PMvIsionalS\Coted Concrete ReinfotIrg\Coated Concrete ReInforcement - omplete.doc 16

14. A method according to claim 13, wherein pre-treatment includes cleaning and degreasing the surfaces of the reinforcing material.

15. A method according to claim 13 or 14, wherein pre-treatment includes at least 5 one of pickling or blasting the reinforcing material to substantially remove surface impurities from the material.

16. A method according to any preceding claim, wherein the reinforcing material is selected from metal fibres, metal rods, steel fibres, steel rods, metal alloy fibres, metal 10 alloy rods, metal, metal alloys, steel, stainless steel, aluminium, copper, material plated with metal, deformed metal bars, mesh, fabricated ligatures or combinations thereof.

17. A method according to any preceding claim, wherein the enamel coating 15 material comprises an enamel slip.

18. A method according to any preceding claim, wherein at least one of the enamel coating material of the first coating step or glass flux of the second coating step includes an acid and alkaline resistant frit. 20

19. A method according to any preceding claim, wherein the further coating material comprises a mixture of dry portland cement and a powdered glass frit.

20. A method according to any preceding claim, wherein the second coating 25 comprising a mixture of a volume amount of between 40 to 70% cementitous material and between 60 to 30% glass flux.

21. A coated reinforcing material formed using a method according to any one of the preceding claims. 30

22. A coated reinforcing material comprising: a base reinforcing material having an exterior surface; at least one enamel coating substantially coating the exterior surface of the base reinforcing material; and X:\ECP\Patent SpecificatnsProvtsionals\Coated Concrete RenordngCoated Concrete Reinforcement - ornplete.doc 17 at least one further coating applied over the enamel coating comprising a mixture of cementitous material and glass flux.

23. A coated reinforcing material according to claim 22, wherein the reinforcing 5 material is selected from metal fibres, metal rods, steel fibres, steel rods, metal alloy fibres, metal alloy rods, metal, metal alloys, steel, stainless steel, aluminium, copper, material plated with metal, or combinations thereof.

24. A coated reinforcing material according to claim 22 or 23, wherein at least one 10 of the enamel coating or glass flux includes an acid and alkaline resistant frit.

25. A coated reinforcing material according to claim 22, 23 or 24 formed using a method according to any one of claims 1 to 20. 15

26. A coated reinforcing material and/or method of producing a coated reinforcing material substantially as herein described in accordance with the accompanying drawings. X:\ECP\Paten Spedficatons\ProvIsonals\Coated Concrete ReInforcing\Coated Concete ReInforem ent - omplete.doc