AU2010202310A1 - Concrete structure - Google Patents

Description

S&F Ref: 954310 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Boral Resources (Vic.) Pty Limited, of Applicant: an Australian company, ACN 004 620 731, of 1 Glenferrie Road, Malvern, Victoria, 3144, Australia Actual Inventor(s): Damian Augustine Hope Mario Tabone Leo Boesten Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Concrete structure Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2009902674 11 Jun 2009 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(2751052_1) 1 CONCRETE STRUCTURE Technical Field The present invention relates to the field of concrete, and particularly to concrete 5 structures having decorative surfaces. Background of the Invention Various forms of decorative concrete are known, providing a finished surface for floors, driveways, public thoroughfares and the like without the need for decorative floor 1o coverings such as tiles, floor boards, carpet or the like. One form of decorative concrete utilises an exposed aggregate finish whereby coarse aggregate is exposed on the surface of the concrete rather than concealed by a thin layer of cement topping as is the usual arrangement. Coarse aggregates for use in exposed aggregate finishes are known in a variety of materials, colours and grades. is Coarse aggregates that are intended to provide the exposed surface of the concrete may be added to the concrete in a number of ways. They can be incorporated integrally throughout the entire concrete mix, contained in a topping mix that is either poured during construction of the concrete slab (known as monolithic toppings) or poured over an existing concrete slab. An exposed aggregate finish can also be achieved by seeding the 20 surface, a process whereby pieces of coarse aggregate are cast over the surface of the concrete immediately after screeding and then bull floated into the surface prior to bleed water appearing, or alternatively applied to the surface once all bleed water has evaporated and then embedded by tapping and repeatedly working the surface with a wood float. To create intricate patterns, pieces of aggregate are generally set into the 25 surface of the concrete manually using various methods. Once the pieces of aggregate are in place, the aggregate may be exposed by any of various methods including water washing, abrasive blasting, honing and acid etching. Exposed aggregate finishes are most typically utilised for outdoor applications including paths, driveways and public thoroughfares. 30 Another form of known decorative concrete involves the use of a polished concrete finish. Polished concrete finishes are typically provided by any of three basic methods that can be used to polish either the surface of the concrete slab itself or a concrete topping layer poured subsequent to the underlying slab. A first typical method involves steel trowelling of a concrete surface. This polished finish is typically used 35 when a basic smooth, flat finish is required. A second known method, burnishing, 2 provides a harder wearing durable finish with a surface lustre that is typically produced by steel trowelling the surface until the concrete surface gains a polished or glossy appearance. A preferred methodology hones the surface of the concrete to provide a smooth low maintenance and durable finish produced by grinding the surface with 5 abrasive. The grinding is generally carried out to a sufficient degree to expose aggregate immediately beneath the surface of the concrete, thereby contributing to the overall decorative appearance of the concrete surface. Polished finishes are often utilised in indoor flooring applications. 10 Summary of the Invention In a first aspect, the present invention provides a concrete structure having an exposed surface incorporating an exposed photoluminescent aggregate. The photoluminescent aggregate may be resin-based and include a photoluminescent pigment. is The pigment may be aluminate based. The pigment may be an inorganic alkaline earth halo aluminate oxide. The photoluminescent aggregate may alternatively be ceramic based. The photoluminescent aggregate may be confined to a surface layer of said concrete structure defining said exposed surface. 20 Alternatively said photoluminescent aggregate may be distributed throughout the thickness of said concrete structure. In one form, said concrete structure is a ground slab. The ground slab may form at least part of a footpath, driveway or public thoroughfare. In another form, said concrete structure comprises a floor slab. 25 The photoluminescent aggregate may be arranged in a predetermined pattern. The photoluminescent aggregate may be arranged to define a path along said exposed surface. In a second aspect, the present invention provides a method of forming a decorative exposed surface in a concrete structure comprising the step of providing 30 photoluminescent aggregate in at least a surface layer of said concrete structure defining said exposed surface so as to be exposed onto said exposed surface. In one form, said method comprises seeding said photoluminescent aggregate into said surface layer following pouring of said concrete structure. The method may include the step of exposing said photoluminescent aggregate 35 by blasting, honing or etching.

3 Alternatively, said method comprises locating said photoluminescent aggregate throughout a thickness of said concrete structure by mixing said photoluminescent aggregate with a concrete mix from which said concrete structure is formed. In one form, said coarse aggregate may be located in said surface layer so as to 5 define a path. Brief Description of the Drawings Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings wherein: 10 Figure 1 is a perspective view of a concrete structure; Figure 2 is a cross-sectional view of the concrete structure of Figure 1; Figure 3 is a cross-sectional view of an alternate form of the concrete structure of Figure 1; Figure 4 is a perspective view of a concrete structure with an exposed surface is defining a path. Detailed Description of the Preferred Embodiments Referring to Figure 1 of the accompanying drawings, a concrete structure 1, in the form of a concrete slab has an exposed surface 2. For a concrete slab that is intended 20 to form a ground slab or floor slab, the exposed surface 2 will typically be the uppermost surface of the concrete structure 1. The exposed surface 2 incorporates an exposed photoluminescent aggregate 3, in the form of pieces of photoluminescent aggregate distributed across the exposed surface 2. The photoluminescent aggregate 3 absorbs light when exposed to sunlight or artificial light, and then light is re-emitted over an extended 25 period as an afterglow, most visible when the exposed surface 2 is otherwise in darkness. The concrete structure I is thus able to glow in the dark, providing a decorative visual effect. The pieces of photoluminescent aggregate 3 may vary in size as required, but will typically be sized from 2 mm to 30 mm. The photoluminescent aggregate 3 may be 30 any desired shape which may include regular shapes such as spheres, or irregular shapes to more closely imitate standard irregular aggregates. The photoluminescent aggregate 3 will typically include a photoluminescent pigment to provide it with its photoluminescent properties. The aggregate 3 may be resin-based, with the photoluminescent pigment mixed with a flowable resin subsequently cured into the desired shaped aggregate. 35 Suitable resins include acrylic and polyester resins. One specific suitable resin is 4 ESTAREZ@ 3109p polyester resin available from Nupol Composites of Botany, New South Wales, Australia. This resin is a water white, waxed, non-phyxotropic pre accelerator orthophthalic polyester resin primarily formulated for synthetic marble casting and embedding applications. Typically, between 10% and 30% by weight of the 5 photoluminescent pigment is blended with the resin in a liquid form and allowed to harden into an aggregate shaped photoluminescent "stone". Rather than being resin based, it is also envisaged that the aggregate may be ceramic based and, again, including a photoluminescent pigment. The photoluminescent pigment may be aluminate based and, specifically, may be to an inorganic alkaline earth halo aluminate oxide. It is also envisaged, however, that any suitable photoluminescent pigments may be utilised as desired, including to provide different afterglow colours, such as green, aqua, blue, orange, yellow or offwhite. One particularly suitable range of photoluminescent pigments is the VG range of photoluminescent pigments available from Vision Glow International Pty Ltd of Braeside, is Victoria, Australia. The photoluminescent aggregate may be incorporated into the exposed surface 2 by any available means, including by each of the processes described above. The photoluminescent aggregate 3 may be confined to a surface layer 4 of the concrete structure that defines the exposed surface 2 as depicted in Figure 2. This is 20 typically achieved by seeding the exposed surface 2 in a known manner following pouring of the concrete. Alternatively, referring to Figure 3, the photoluminescent aggregate 3 may extend through the thickness of the concrete structure I by being added to the concrete mix prior to pouring of the concrete structure 1. The concrete structure I will typically also include regular stone aggregate 5 in addition to the photoluminescent 25 aggregate. In one specific process, a standard concrete mix consisting of stone aggregate, natural or manufactured sand, cement (which may comprise Portland cement, blended cement, offwhite cement or cement alternatives) and concrete additives and admixtures (such as bonding agents, sealing agents, and/or colour pigments) is mixed with water in 30 the usual manner. The concrete mix is then poured in the usual manner, vibrated and screeded to provide a dense level exposed surface 2. The photoluminescent aggregate 3 is then broadcast over the exposed surface of the concrete structure 1, whilst the concrete is in a plastic state. Where a random finish is desired, the photoluminescent aggregate 3 may be broadcast utilising a mechanical spreader or by hand. If a particular decorative 35 pattern is desired, the photoluminescent aggregate 3 will typically be placed on the 5 exposed surface 2 in the desired pattern by hand. The photoluminescent aggregate 3 is then pressed into the exposed surface 2 of the plastic concrete utilising a roller, float, timber planks or any other suitable method. The photoluminescent aggregate 3 will typically be pressed into the exposed surface 2 until it is level with the exposed surface 2. 5 If required, the surface may be subjected to limited finishing to ensure that the concrete mix fills any gaps around the introduced photoluminescent aggregate 3. If a rough exposed surface 2 is desired with the photoluminescent aggregate projecting beyond the surface of the concrete, a set retarding agent will typically be applied to the exposed surface 2 of the concrete structure so as to retard setting of the 1o surface layer 4 of the concrete structure (without affecting set of the main body of concrete mix located beneath the surface layer). Once the main body of concrete has set, the exposed surface 2 is washed with water, so as to wash away part of the surface layer 4, thereby exposing the photoluminescent aggregate 3 and stone aggregate 5. Alternatively, the top of the surface layer 4 may be removed by sand blasting, without the is use of set retarders, so as to provide a similar result. When a polished finish is desired, the same process may be followed with the exception of applying set retarder and washing the exposed surface 2. The concrete is allowed to set, typically for a minimum of seven days so as to achieve suitable strength, then the exposed surface 2 is honed by grinding between 2 mm and 10 mm off the surface 20 so as to expose the photoluminescent aggregate 3 (and stone aggregate 5), providing a polished exposed surface 2 that is particularly suitable for indoor flooring applications. The polished exposed surface 2 may be left as is, or have sealers applied to protect the surface. The use of photoluminescent aggregate 3 as described above may be utilised for 25 various applications. The photoluminescent aggregate 3 may be utilised purely for decorative effect, either in a random pattern or predetermined ordered pattern. Referring to Figure 4, it is also envisaged that the photoluminescent aggregate 3 may be arranged in a specific pattern in the exposed surface so as to define a path 6 for guiding pedestrians, vehicles or the like depending upon the application. When defining such a 30 path 6, the photoluminescent aggregate 3 will typically be arranged in two lines 7 defining opposing edges of the path 6, or alternatively a single line extending along the path 6. The use of powered lighting may thus be reduced in such applications. Use of the photoluminescent aggregate 3 as described will be particularly suitable for ground slabs, forming at least part of walkways, driveways or public 35 thoroughfares such as footpaths, roads or malls, or for floor slabs forming indoor floor 6 surfaces. It is also envisaged that the photoluminescent aggregate 3 may be utilised in exposed surfaces of concrete wall structures, ceiling structures and any of other various concrete structures.

Claims (14)

1. A concrete structure having an exposed surface incorporating an exposed photoluminescent aggregate. 5 2. The concrete structure of claim 1, wherein said photoluminescent aggregate is resin-based and includes a photoluminescent pigment.

3. The concrete structure of claim 2, wherein said pigment is aluminate based. 10

4. The concrete structure of claim 3, wherein said pigment is an inorganic alkaline earth halo aluminate oxide.

5. The concrete structure of claim 1, wherein said photoluminescent 1s aggregate is ceramic based.

6. The concrete structure of any one of claims I to 5, wherein said photoluminescent aggregate is confined to a surface layer of said concrete structure defining said exposed surface. 20

7. The concrete structure of any one of claims I to 5, wherein said photoluminescent aggregate is distributed throughout the thickness of said concrete structure. 25 8. The concrete structure of any one of claims I to 7, wherein said concrete structure is a ground slab.

9. The concrete structure of claim 8, wherein said ground slab forms at least part of a footpath, driveway or public thoroughfare. 30

10. The concrete structure of any one of claims 1 to 7, wherein said concrete structure comprises a floor slab. 1L. The concrete structure of any one of claims I to 10, wherein said 35 photoluminescent aggregate is arranged in a predetermined pattern. 8

12. The concrete structure of claim 11, wherein said photoluminescent aggregate is arranged to define a path along said exposed surface.

13. A method of forming a decorative exposed surface in a concrete s structure comprising the step of providing photoluminescent aggregate in at least a surface layer of said concrete structure defining said exposed surface so as to be exposed onto said exposed surface.

14. The method of claim 13, said method comprising seeding said to photoluminescent aggregate into said surface layer following pouring of said concrete structure.

15. The method of claim 14, wherein said coarse aggregate is located in said surface layer so as to define a path. 15

16. The method of claim 13, said method comprising locating said photoluminescent aggregate throughout a thickness of said concrete structure by mixing said photoluminescent aggregate with a concrete mix from which said concrete structure is formed. 20

17. The method of any one of claims 13 to 16, wherein said method includes the step of exposing said photoluminescent aggregate by blasting, honing or etching. 25 18. A concrete structure substantially as hereinbefore described with reference to Figures 1 and 2, Figure 3 or Figure 4 of the accompanying drawings. Dated 3 June, 2010 Boral Resources (Vic.) Pty Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON