AU2005244578B2

AU2005244578B2 - Reinforced cementitious material product and method of manufacture of the same

Info

Publication number: AU2005244578B2
Application number: AU2005244578A
Authority: AU
Inventors: Philip Morey
Original assignee: AUSTRAL BRICK Co Pty Ltd
Current assignee: AUSTRAL BRICK Co Pty Ltd
Priority date: 2004-12-16
Filing date: 2005-12-16
Publication date: 2012-03-15
Anticipated expiration: 2025-12-16
Also published as: AU2005244578A1

Abstract

A reinforced cementitious material product, including a reinforcement structure 10 extending in three dimensions within the product. [Figure 1] yI ISO, is0

Description

AUSTRALIA Patents Act COMPLETE SPECIFICATION (ORIGINAL) Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: The Austral Brick Company Pty Ltd Actual Inventor(s): Address for Service and Correspondence: PHILLIPS ORMONDE & FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street elbourne 300Q USTRAQlA Invention Title: REINFORCED CEMENTITIOUS MATERIAL PRODUCT AND METHOD OF MANUFACTURE OF THE SAME Our Ref: 761871 POF Code: 468645/468645, 470768 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): - 1- 2 REINFORCED CEMENTITIOUS MATERIAL PRODUCT AND METHOD OF MANUFACTURE OF THE SAME Field of the invention 5 The present invention relates to reinforcement of cementitious material products, including lightweight concrete or other cement or gypsum, including those for flat panel systems, such as for use in buildings or other applications. 10 Background of the invention Cementitious materials, including lightweight cementitious materials, are used in the making of panel products. These panel products can be used in the construction of buildings, for example in floors, roofs and walls. Panels are 15 moulded during production and then moved to a storage location before being transported to the building site of the building to be constructed. Use of cementitious materials, such as concrete, in construction of buildings provides design flexibility and substantial cost savings. However, after 20 formation and curing of the concrete, specialised equipment may be required to ensure the prevention of fracture and ultimate loss of usefulness of panels during shipment to the construction location. Generally, the specialised equipment must support the entire length of the panel, in order to avoid flexing of the panel, which can cause fracture due to the brittle nature of the material. 25 Where lightweight concrete is used, this problem is increased, due to the reduced structural capability of the lighter material. The above discussion of background art is included to explain the context of the present invention. It is not to be taken as an admission that any of the 30 material referred to was published, known or part of the common general knowledge at the priority date of any one of the claims of this specification.

3 Summary of the Invention According to a first aspect of the invention, there is provided a reinforced cementitious material building product in the form of a solid panel for use in construction, including a metal 5 reinforcement structure extending in three dimensions within the panel, the reinforcement structure including at least one substantially planar grid, wherein the reinforcement structure is surrounded by a cementitious material that is lightweight concrete to form the solid panel. Preferably, the lightweight concrete contains polystyrene as an aggregate. 10 The reinforcement structure is preferably substantially un-prestressed. The reinforcement structure may be in the form of a lattice. The reinforcement cementitious material product may be formed as a flat panel. 15 The reinforcement structure may include a substantially planar grid, extending in the plane of the panel for substantially the length of the product. The structure preferably also includes a second grid, joined to the planar grid, with at least part of the second grid being deformed to extend away from the plane of the planar grid. 20 The planar grid is preferably a rectangular grid formed of crossed bars joined together. The second grid is also preferably a rectangular grid formed from crossed bars joined together, bent away from the plane of the planar grid to form a triangular section. According to a second aspect of the invention, there is provided a method of manufacturing a 25 reinforced lightweight concrete material building product in the form of a solid panel, the method including providing a lightweight concrete material mix, placing a metal reinforcement structure, extending in three dimensions, in a mould, the metal reinforcement structure including at least one substantially planar grid placing the mix into the mould around the metal reinforcement structure, allowing the mix to at least partially cure, and removing the at least 30 partially cured lightweight concrete material building product in the form of a solid panel from the mould. Preferably, the reinforcement structure is substantially unstressed when it is placed in the mould. Preferably, the mould is vibrated after placing of the mix, to facilitate removal of 35 excess air from the mix. C :V\ WOrdSPEC-78 71. doc 4 According to a third aspect of the invention, the invention extends to use of a metal structure extending in three dimensions within a lightweight concrete material building product in the form of a solid panel for reinforcement of the panel, the metal structure including at least one 5 substantially planar grid. Brief Description of the Drawings Specific embodiments of the invention will now be described, purely by way of example, with 10 reference to the following drawings, in which: Figure 1 shows a first view of a reinforcement structure to be used in a cementitious material according to an embodiment of the invention; 15 Figure 2 shows a side view of the reinforcement structure of Figure 1; Figure 3 shows an elevation of the reinforcement structure of Figures 1 and 2; Figures 4a and 4b show plan and end views respectively of a reinforcement structure to be 20 used in a cementitious material according to an embodiment of the invention; Figure 5 shows a cementitious material product according to an embodiment of the invention; Figure 6 shows a further cementitious material product according to an embodiment of the 25 invention. Specific Description of Embodiments of the Invention C:1pofwrI\SPEC-761871.doc 4a Figure 6 shows a further cementitious material product according to an embodiment of the invention. 5 Specific Description of Embodiments of the Invention SPEC-761871 doc 5 Figure 1 shows in plan view a three-dimensionally extending reinforcement structure 10 for use in a cementitious material product according to an embodiment of the invention. The reinforcement structure 10 includes a 5 substantially planar flat grid 15 including two sets of substantially mutually perpendicular evenly spaced steel bars 12, 14, welded together. The bars 14 in one set of the flat grid 15 are longer than those in the other set 12. Six such longer 14 bars are provided in the present embodiment. The flat grid 15 is therefore elongate in the direction of the longer bars 14. 10 A second, deformed, grid 20 is also included, made from two further sets of substantially mutually perpendicular evenly spaced steel bars 16, 18a and 18b welded together. In the present embodiment, the bars of each grid are 4mm diameter and are spaced apart at 100 mm intervals. Once again, the bars 15 18a, 18b in one of the further sets are longer than those in the other set 16, and are substantially the same length as the longer bars 14 in the flat grid 15. Three longer bars 18a, 18b are provided in the present embodiment. The deformed grid 20 is deformed by bending along a line formed by a central 20 longer bar 18a, to form a triangular shape in a section through the deformed grid 20 parallel with the shorter bars 16. This shape is shown in Figure 2, with outer longer bars 18b at each apex of the triangle and the shorter bars 16 forming two of the sides of the triangle. The deformed grid 20 is placed on one side of the flat grid 15. The two grids 15, 20 are aligned so that the longer 25 set of bars 14, 18a, 18b from each grid 15, 20 are parallel. The outer longer bars 18b of the deformed grid 20 are welded onto one side of the flat grid 15, to form a three dimensional lattice structure. Figure 3 shows a side elevation of the three-dimensional reinforcement 30 structure 10 of Figures 1 and 2. The central longer bar 18a of the deformed grid 20 extends along the elongate axis of the flat grid 15, with the set of shorter bars 16 of the deformed grid 20 supporting the central longer bar 18a of the deformed grid 20 away from the flat grid 15.

6 The three-dimensional shape of the structure gives it rigidity along its length, aided by the substantially parallel alignment of the bar 18a in the deformed grid 20 with the length of the flat grid 15, and the offset of the bar 18a and flat grid 15 in the direction of the deformation of the deformed grid 20. This 5 alignment reduces flexing of the length of the structure. The bend in the deformed grid 20 also reduces flexing across the width of the panel, as any flexing in this direction requires the shorter bars 16 of the deformed grid 20 to bend out of their deformed shape, as well as requiring the shorter bars of the flat grid 14 to bend. 10 Figure 4a shows in plan view an alternative three-dimensionally extending reinforcement structure 30 similar to the deformed grid 20 of Figures 1 to 3 for use in a cementitious material product according to an embodiment of the invention. The reinforcement structure 30 is a deformed grid 32 including two 15 sets of substantially mutually perpendicular evenly spaced steel bars 34, 36a, 36b, welded together. The bars 36a, 36b in one set of the deformed grid 30 are longer than those in the other set 34. Three such longer bars 36a, 36b are provided in the present embodiment. The deformed grid 32 is therefore elongate in the direction of the longer bars 36a, 36b. 20 The deformed grid 32 may be formed by bending along a line formed by a central longer bar 36a, to form a "V" shape in a section through the deformed grid 32 parallel with the shorter bars 34. This shape is shown in side view in Figure 4b with outer longer bars 36b at the apex of the "V" shape and the 25 shorter bars 34 forming two of the legs of the "V" shape. Advantageously, use of the deformed grid 32 without the substantially flat grid 15 described in Figures 1 to 3 above, uses less material which results in a lighter reinforced cementitious material panel while still providing reinforcement strength. 30 In order to make a reinforced cementitious material panel, the reinforcement structure is placed in a mould. The reinforcement structure of Figure 1 or Figures 4a and 4b is placed in the mould vertically and rests in contact with the an end of the mould. Alternatively, the reinforcement structure of Figure 1 or Figures 4a and 4b is placed in the mould horizontally and rests in contact 7 with the base of the mould. The reinforcement structure is not stressed or deformed further when it is placed in the mould. A cementitious material mix is poured into the mould. In alternative 5 embodiments, the cementitious material may be pumped into the mould. Many cementitious materials may be used. In the present embodiment, the cementitious material is a lightweight concrete mix making use of polystyrene as an aggregate. Other aggregates may also be used, including air. In the present embodiment, the density is around 0.5g/cm 3 . However, the density of 10 the concrete mix may be up to more than 2g/cm 3 . The density may be any value below this. Preferably, the density is between 0.3g/cm 3 and 0.7g/cm 3 , preferably between 0.4 g/cm 3 and 0.6g/cm 3 . Below a density of 0.7-0.8g/cm 3 , a cementitious material may be said to be lightweight. 15 Once the concrete mix is in the mould, the mix surrounds the reinforcement structure. Where air is not used as an aggregate, the mould is vibrated while the mix is still liquid, in order to remove excess air trapped in the mould. The concrete mix is then left in the mould to harden and cure. In the present 20 embodiment, the concrete mix is left to cure for around 12 hours, although in alternative embodiments, the time may be reduced to around 8 hours. Once the concrete mix has hardened and cured, it is removed from the mould in the form of a panel. The hardened and cured panel is internally reinforced 25 by the structure, which is internally bonded within the panel by the action of the cementitious mix enveloping or surrounding the metal of the structure. The cementitious material is not prestressed by the reinforcement structure, as the reinforcement structure was not placed under stress when in the mould. Figure 5 shows a product according to an embodiment of the 30 invention with the internal reinforcement structure 40 of Figure 1 shown in broken lines. Figure 6 shows a product according to an embodiment of the invention with the internal reinforcement structure 50 of Figures 4a and 4b shown in broken lines.

8 The reinforcement structure allows the panel to be handled without the need for specialised equipment. Flexing and bending of the panel along its length is reduced by the reinforcement structure. For example, the panel may be lifted by one end only, with the reinforcement structure reducing the amount of 5 flexing of the panel due to its own weight. This reduction in bending of the panel reduces the degree of fracture of the cementitious material, retaining the usefulness of the panel, while allowing ease of handling. In the embodiments described above, steel bars have been used. Other 10 types of materials, preferably high tensile materials including high tensile metals can also be used. Plastic materials could be used. Additionally, although three long bars 18a, 18b have been shown in the deformed grid 20 of Figures 1 to 3 and six long bars 14 in the flat grid 15, it will be appreciated that larger or smaller grids can be made according to the invention. In the 15 embodiments described above, a structure 3m long, 0.6m wide and extending in the third dimension by around 60mm to 75mm is used. The width of the reinforcement structure need not extend across the whole width of the panel. It may, for example extend over around two thirds of the panel, although in the present embodiment, it extends across the whole width of the panel. The 20 structure need not extend for the whole thickness of the panel, although it may do so, as required. In the embodiment described above, the reinforcement structure sits 5 to 10mm from the surface edges of the panel. Additionally, it will be appreciated that in the embodiment of Figures 1 to 3 the 25 grids 15 and 20 could be joined together and/or to each other using methods other than welding, such as brazing or tying etc. One or both of the grids 15 and 20, or the grid 30 may be non-rectangular grids, such as triangular or other regular or irregular polygonal shape. In 30 addition, while a single bend in the deformed grid has been described in detail, it will be appreciated that the deformed grid could be formed in other ways, such to form a three-sided rectangular channel or to form a corrugated, semicircular or another shape of bend giving a three dimensional shape to the reinforcement structure. The invention does not require two separate grids to 9 be provided. A single grid, bent into, for example, a rectangular section could also be used. Further, the use of one or more grids is not essential; the structure may include other configurations within the product that extend in three dimensions. Metal sheet could for example be employed, as could 5 plastic or fibreglass sheeting. Other materials could be used to form the reinforced structure. It will be appreciated that various other omissions, additions and/or modifications will present themselves to one skilled in the art, and all such 10 omissions additions and modifications are within the scope and spirit of the invention.

Claims

1. A reinforced cementitious material building product in the form of a solid panel for use in construction, including a metal reinforcement structure extending in three dimensions within the panel, the reinforcement structure including at least one substantially planar grid, extending in the plane of the panel for substantially the length of the panel, wherein the reinforcement structure includes a second grid, joined to the planar grid, with at least part of the second grid being deformed being deformed to extend away from the plane of the planar grid, wherein the second grid is also a rectangular grid formed from crossed bars joined together, bent in the direction of one of the bars extending in the length direction of the panel, to form a triangular section, wherein the reinforcement structure is surrounded by a cementitious material that is lightweight concrete to form the solid panel.

2. The reinforced cementitious material building product of claim 1, wherein the panel is a floor panel, a wall panel, or a roof panel for use in the construction of a building.

3. A reinforced cementitious material building product according to claim 1 or 2, wherein the lightweight concrete contains polystyrene as an aggregate.

4. A reinforced cementitious material building product according to any one of the preceding claims, wherein the reinforcement structure is substantially un-prestressed.

5. A reinforced cementitious material building product according to any one of the preceding claims, wherein the reinforcement structure is in the form of a lattice.

6. A reinforced cementitious material building product according to any one of the preceding claims, formed as a flat panel.

7. A reinforced cementitious material product according to any one of the preceding claims, wherein the planar grid is a rectangular grid formed of crossed bars joined together.

8. A method of manufacturing a reinforced lightweight concrete material building product in the form of a solid panel, the method including: providing a lightweight concrete material mix; placing a metal reinforcement structure, extending in three dimensions, in a mould, extending in the plane of the panel for substantially the length of the panel, wherein the reinforcement structure includes a second grid, joined to the planar grid, with at least part of the second grid being deformed being deformed to extend away from the plane of the planar grid, wherein the second grid is also a rectangular grid SPEC-761871.doo 11 formed from crossed bars joined together, bent in the direction of one of the bars extending in the length direction of the panel, to form a triangular section, placing the mix into the mould around the metal reinforcement structure; allowing the mix to at least partially cure; and 5 removing the at least partially cured lightweight concrete material building product in the form of a solid panel from the mould.

9. A method according to claim 8, wherein the panel is a floor panel, a wall panel, or a roof panel for use in the construction of a building.

10. A method according to claim 8 or 9, wherein the reinforcement structure is 10 substantially unstressed when it is placed in the mould.

11. A method according to any one of claims 8 to 10, wherein the mould is vibrated after placing of the mix, to facilitate removal of excess air from the mix.

12. Use of a metal str.ucture extending in three dimensions within a lightweight concrete material building product in the form of a solid panel for reinforcement of the panel, the metal 15 structure including at least one substantially planar grid, extending in the plane of the panel for substantially the length of the panel, wherein the reinforcement structure includes a second grid, joined to the planar grid, with at least part of the second grid being deformed being deformed to extend away from the plane of the planar grid, wherein the second grid is also a rectangular grid formed from crossed bars joined together, bent in the direction of one 20 of the bars extending in the length direction of the panel, to form a triangular section,

13. A reinforced lightweight concrete material building product in the form of a panel, as defined in claim 1, substantially as herein described with reference to the accompanying drawings of embodiments of the invention.

14. A reinforced lightweight concrete material building product in the form of a panel 25 including a metal reinforcement structure, as defined in claim 1, substantially as hereinbefore described with reference to the accompanying drawings of embodiments of the invention. SPEC-76i87tdoc