GB2307707A

GB2307707A - Colouring road surfaces

Info

Publication number: GB2307707A
Application number: GB9625041A
Authority: GB
Inventors: Peter Shaun Finucane
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-02
Filing date: 1996-12-02
Publication date: 1997-06-04
Anticipated expiration: 2016-12-02
Also published as: GB9524713D0; GB2307707B; GB9625041D0

Abstract

The invention provides for the substitution of non-black aggregate material, principly by bricks, as an alternative to primary extracted aggregates for roads, principly road surfaces. The invention provides benefits in terms of reduced aggregate costs, recycling instead of disposal or redundant bricks and a more cost effective way for generating coloured road surfaces. The aggregate is provided in sizes between 5 and 80mm, preferably 10 to 20mm. The brick material may be waterproofed by means of a silica wash. It is applied as a hot or cold rolled material.

Description

IMPROVEMENTS IN AND RELATING TO SURFACES This invention is concerned with improvements in and relating to surfaces, particularly but not exclusively, in relation to road surfaces, footpaths and the like.

At present the vast majority of road, footpath and drive way surfaces are formed from black bitumastic tarmacadam consisting of a bitumous binder and an appropriately sized aggregate, the aggregate being obtained from a primary source ie quarried.

If a more friendly hue to the surface is needed or different colours are needed to designate particular vehicular traffic controls, secure areas, lanes for cyclists and the like, chemical pigments are introduced to the tarmacadam.

A particularly commonly employed pigment in this regard is red. Unfortunately such surfaces are at least 30% dearer than the conventional black tarmacadams. This additional cost is as a result of the expensive pigments which must be employed. As such the use of coloured surfaces of this type are presently restricted to more prestigious or essential areas due to the costs involved.

Amongst the aims of the present invention is to provide a surface with an alternative colouring to black, but to do so in a cost effective manner.

According to a first aspect of the invention we provide a road surface material comprising a binder material, preferably bitumous, and non-black coloured aggregate material, most preferably brick.

In this way using the colour inherent in the aggregate a suitable coloration is provided without the need for expensive pigments.

Preferably the material employed consists of crushed bricks, particularly red bricks. In this way the appropriate aggregate size can be provided.

It is particularly preferred to provide the bricks as source from recycled materials. In this way not only is an effective road surface provided, but the technique also provides valuable environmental spin offs, such as a saving in raw materials, reduced land fill requirements (as bricks from demolition are usually dumped) and a potential cost saving through recycling.

The brick or brick pieces may comprise 85 to 98% of the surface. More preferably a level of 90 to 95% is provided.

The aggregate may be provided in sizes between 5 and 80mm. Sizes of 20 to 80mm, or approximately 40mm may be suitable for roads. Sizes of 5 to 30mm may be suitable for footpaths and the like. A size range of 10 to 2Omm is particularly preferred.

The brick material employed may be waterproofed, for instance by means of a silica wash.

According to a second aspect of the invention we provide a method of forming a road surface comprising; a) obtaining a supply of bricks; b) the reduction in size of the brick material to the required level; c) the introduction of the bricks to a bituminous binder; and d) the application of the combined material to form a road surface.

In this way pigmented road surfaces can be provided in a cost effective manner. Steps c) and d) may be reversed or occur practically simultaneously Preferably the crushed material is screened to remove over and under sized material before use. It is particularly preferred to remove dust, which could easily arise during the size reduction of bricks.

The method may include the further step of waterproofing or otherwise sealing the brick material. Most preferably this step is undertaken following screening so that the material is only used to coat the aggregate particles which are already of the correct size.

Preferably the source of brick material consists of at least some recycled bricks, for instance demolition waste.

Where recycled bricks are to be used, particularly from demolition waste, it is desirable to employ an initial segregation or screening stage to exclude concrete, metal, timber and other extraneous materials. In this way milling costs can be minimised, the milling stage can be protected from damage and the presence of undesirable components in the eventual road surface can be avoided. The bricks may alternatively or additionally be obtained from waste streams, surpluses or "seconds" from brick manufacturers.

The brick may be of the clay based and / or sand-lime and / or flint - lime type.

The material may be applied as a hot or cold rolled material.

According to a third aspect of the invention we provide a method for pigmenting an area for vehicular or pedestrian traffic comprising the provision of brick pieces in a binder.

Various embodiments of the invention will now be described, by way of example only.

The use of recycled bricks as the source for the aggregate in the present material is particularly desirable as such materials are readily available and presently represent a cost burden to people seeking to dispose of them.

At present bricks, from demolition sites for instance are disposed of in the easiest way possible. This is usually as tipped material into land fill sites, but occasionally as crushed base materials beneath foundations of buildings or roads. As a demolition contractor is charged by volume or weight for disposal of such controlled weight this represents a significant cost burden to them. This cost burden has risen significantly with the new environmental laws now in force.

The use of recycled brick material has additional advantages as it avoids the need to extract new materials, often from environmentally sensitive areas, and provide a useful disposal route for existing products. In addition the coloration already present in such materials allows the desirable coloured surfaces to be obtained at low cost.

A road surface formed of brick pieces is also advantageous over pigmented roads as whilst pigments fade with use, the bricks remain consistent in their colour. Indeed the colouration may even increase as the amount of brick surface exposed increases, for instance through wear.

A particular embodiment for producing such a material consists of an initial screening stage during which concrete, metal and timber for instance are excluded from the feed to a production facility. Conventional screening techniques, such as magnets could be used in this regard. Suitable screening plants to extract such materials may be provided at or near land fill sites and indeed such facilities may be offered free to parties seeking to dispose of the materials in exchange for ownership of the aggregates.

The material screened of tramp elements is then fed to a screening stage at which undersized material is removed and discarded. Dust may for instance be removed by washing. The material may be further divided into large and middle sized fractions to determine the milling stage to which they are fed.

Single or multi stage milling, with screening between each and recycling of oversize to the mill is employed to generate an aggregate of the required size. A 10 to 20mm size fraction is particularly preferred in this regard.

Once present in the required size fraction the aggregate is subjected to a washing stage to remove surface dust, before the material is sealed to render it waterproof, for instance by a silica wash. Waterproofing is potentially desirable as when clay based bricks are employed water absorption may occur in use. This is potentially undesirable as the potential for frost damage is increased.

The final, sized and sealed product can then be transported to the desired location for use where it can be introduced to the bitumous binder before application or be applied to it afterwards followed by a rolling in stage.

A hot rolling technique can be used where the tarmacadam is formed by mixing the binder, aggregate and pigment, in the form of brick pieces, together at 1000C or more and then applying it to the desired location to provide the surface.

Alternatively a cold rolled process can be employed where the hot asphalt is laid and the cold aggregate is distributed over its surface and rolled in. Cold rolling offers the possibility of very closely controlling the pigmented areas formed by the application of the brick pieces. Different brick colours to give different pigmentation can be applied to quite small discrete areas in this way.

An appropriately coloured, pleasantly ornamental and cost effective road surface is thus provided. A material according to the present invention provides the top 40mm or so course.

As used in this application a road surface is taken to include references to drive ways, car parks, hard standing areas, footpaths and other such areas which may be open to vehicular or pedestrian traffic.

The polished stone value and other properties of the road surface are carefully controlled to ensure adequate skid resistance and other equivalent properties to existing employed materials. These may for instance be controlled by varying the type and / or proportion of brick pieces, binder and / or conventional aggregate present.

Claims

CLAIMS:

1. A road surface material comprising a binder material, and non-black coloured aggregate material.

2. A road surface according to claim 1 in which the aggregate material includes brick.

3. A road surface according to claim 1 or claim 2 in which the material employed consists of crushed bricks, particularly red bricks.

4. A road surface according to any of claims 1 to 3 in which the binder is bituminous.

5. A road surface according to any of claims 1 to 4 in which the aggregate is provided in sizes between 5 and 80mm.

6. A road surface according to any of claims 1 to 5 in which a size range of 10 to 20mm is provided for the aggregate.

7. A road surface according to any preceding claim in which the brick material employed is waterproofed, for instance by means of a silica wash.

8. A method of forming a road surface comprising; a) obtaining a supply of bricks; b) the reduction in size of the brick material to the required level; c) the introduction of the bricks to a bituminous binder; and d) the application of the combined material to form a road surface.

9. A method according to claim 8 in which the source of brick material consists of at least some recycled bricks.

10. A method according to claim 8 or claim 9 in which the bricks are obtained from waste streams, surpluses or "seconds" from brick manufacturers or demolition waste.

11. A method according to any of claims 8 to 10 in which the crushed material is screened to remove over and under sized material before use.

12. A method according to claim 11 in which the method includes the further step of waterproofing or otherwise sealing the brick material following screening.

13. A method according to any of claims 8 to 12 in which the material is applied as a hot or cold rolled material.