GB2200645A

GB2200645A - Improved material for, and method of, repairing or surfacing roads and the like

Info

Publication number: GB2200645A
Application number: GB08702289A
Authority: GB
Inventors: James Mcintosh; Graham Beeney
Original assignee: FIBRE DEC Ltd
Current assignee: FIBRE DEC Ltd
Priority date: 1987-02-02
Filing date: 1987-02-02
Publication date: 1988-08-10
Anticipated expiration: 2007-02-02
Also published as: GB8702289D0; GB2200645B; GB2200645C

Abstract

A material for repairing roads and other areas comprises a rubberised bitumen mixed with aggregate and chopped glass or other fibres such as polyamide. The bitumen may comprise a water emulsion with small dimensioned aggregate to be applied as a thin slurry overlay or may be rubberised neat bitumen to be used for patching cracked areas, particularly in and around concrete joints, for subsequent treatment with an overlay, the resilient rubberised bitumen being load bearing because of the aggregate and having sufficient tensile strength that reflective cracks are not transmitted to the overlay from the underlying concrete having a large coefficient of thermal expansion.

Description

IMPROVED MATERIAL FOR, AND METHOD OF, REPAIRING OR SURFACING ROADS AND THE LIKE This invention relates to an improved material and process using this material to repair or surface roads, parking areas and other load bearing areas. For example, the method may be applied to aircraft pavements, roads, paths, motorways and footpaths.

The present invention is particular concerned with providing repairs using a material which has some degree of resilience and which has a tensile strength and is thus especially useful where the surface to be repaired is jointed or cracked o spalled. This is particularly useful where one is endeavouring to repair concrete surfaces or surfaces wi't.i a concrete underlay in that the concrete expands and contracts greatly with changes of temperature and if one uses a conventional road surfacing material this is brittle and the movement of the concrete tends to provide reflective cracks from the joints or cracks in the concrete to the surface of the black top, Macadam or other conventional surfacing material.Thus, frequently with old concrete surfaces which have been laid in concrete with expansion joints between adjacent concrete areas, not only do the joints themselves cause difficulty but after a period of use the edges of the joints frequently will crack and one can end up with a substantial degree of cracking or enlargements of the joints and spalling of the concrete, that is the provision of localised crack holes and hollows in the concrete, which, if filled with conventional materials will permit the ready transference of cracks to the applied surfacing material after a relatively small period of use.

The present invention is concerned with the provision of a material which uses rubberised bitumen to give the necessary resilience, is reinforced with aggregate for strengthening purposes and providing load bearing resistance and also includes chopped glass or other fibres to provide a tensile strength.

Thus, in accordance with one aspect of the present invention, there is provided a material for use in repairing or servicing roads, parking areas and other load bearing areas, such material comprising a rubberised bitumen and being characterised by the inclusion, mixed with the rubberised bitumen, of aggregate and chopped glass or other fibres.

A further aspect of the invention provides a method of repairing or surfacing roads, parking areas and other load bearing areas in which a hot rubberised bitumen is applied to the area, characterised in that the rubberised bitumen has aggregate and chopped glass or other fibres mixed therewith.

Where one is using the material of the present invention to repair localised areas of joints or cracking or spalling, the aggregate may be up to as much as 25 mm in maximum dimension although preferably it will be from 3 to 5 mm in maximum dimension to ease application, especially where the depth of application in some areas is quite small. Once the sites of movement, for example expansion joints and cracks, have been covered with material strengthened with aggregate and reinforced with fibre a covering overlay may be applied to render the area fit for use. Typically, this overlay may be of glass fibre strengthened bitumen with a surface dressing as disclosed in our British Patent No 2 081 603. Alternatively, a conventional black top or Macadam surface may be applied to a thickness in excess of 50 mm, frequently as much as 100 or 200 mm.

Where one is using the fibreglass reinforced rubberised aggregate containing bitumen for a slurry process to cover a surface area, the aggregate should have a maximum dimension of 5 mm, preferably approximately 3 mm, and generally the rubberised bitumen will be less resilient, containing less rubber and being a water emulsion, so as to provide a harder and quicker setting surface area which may then be applied to a thickness of 3 to 5 mm. Such a slurry would be particularly suitable for spreading on more lightly loaded paths and the like, where the underlying surface may be crazed or lightly cracked or which has had more badly damaged areas already repaired and filled otherwise, for example with the material of the invention which contains a greater proportion of rubber in the bitumen and possibly larger sized aggregate.

The material of the invention may be mixed on site or may be supplied ready mixed for subsequent melting down and laying.

Rubberised bitumen is known to meet the requirements of British Standard No 2499.

We will describe, by way of example, the use of material of the present invention for repairing joints and cracked or spalled surfaces or providing thin patches to badly worn localised areas. In doing this, the material will comprise approximately 50% of rubberised bitumen with the rubberised bitumen possibly containing fillers, for example fine grain filler in the form of sand. The rubberised bitumen will conventionally comprise 5 to 20% latex or pieces of tyre rubber mixed therein to provide the resilience. For use in patching purposes one would expect at least 10%, preferably 15%, rubber in the rubberised bitumen. The aggregate could have a maximum dimension of preferably 3 to 5 mm although, depending upon the circumstances, a greater maximum dimension could be used, for example even as much as 20 to 25 mm.The fibre, preferably glass, added to the mixture would not normally be more than 5% and in most cases 0.5 to 1.5%, say 1%, is adequate. The hot mixture is applied to the cracks or other surface areas requiring substantial repair and when set the additional covering surface is applied as required.

Thus, as indicated previously, this additional surface may be a glass fibre reinforced bitumen provided with a dressing or a conventional black top Macadam surface. The resilience of the rubber bitumen with the tensile strength provided by the glass fibre prevents reflective cracks passing from the underlaying repaired surface to the top surface of the overlay and the substantial aggregate content of the material enables it to be load bearing and resistant to subsidence when passed over by heavy vehicles.

A relatively thin layer of this material may be applied over localised areas for patching purposes as a membrane subsequently to be covered by an overlay.

While the rubberised bitumen used as expressed above would normally be neat a slurry application can be used with material in accordance with the invention. Such a rubberised slurry would contain a rubberised bitumen emulsion with a small sized aggregate, maximum size of normally about 3 mm although possibly as much as 5 mm so that the material can be applied hot as a thin layer. With this use, the rubber may only comprise 5 to 10% of the bitumen which also, of course, contains water. Such a slurry is particularly useful for applying as a thin repair layer to such surfaces as lightly loaded paths or other walk-on areas which are infrequently used by vehicles although even so the resilience of the rubberised bitumen of the slurry will give a resistance to cracking in conjunction with the tensile strength added by the glass fibres. Such -a slurry would normally be screeded or otherwise applied manually and will be relatively quick-setting.

In general, in all the applications, the proportion of aggregate in the material may be from 40 to 60% although proportions outside this range may be used, depending upon the particular application and the amount of fine grained filler, if any, in the rubberised bitumen.

Preferably, the proportion of aggregate in the material is approximately 50% by weight.

In all these applications, we have referred to glass fibres as being used. Usefully, the glass fibres may be chopped to a length of approximately 30 mm. While we have referred herein generally to the use of glass fibres, it will be appreciated that other materials may be used, for example polyamide fibres, although presently glass fibres are the preferred tensile-strength-imparting material.

Claims

1. A material for use in repairing or servicing roads, parking areas and other load bearing areas, such material comprising a rubberised bitumen and being characterised by the inclusion, mixed with the rubberised bitumen, of aggregate and chopped glass or other fibres.

2. A material according to claim 1, characterised in that the rubberised bitumen material includes 5 to 25% rubber.

3. A material according to claim 2, characterised in that the rubberised bitumen includes not more than 10% rubber, includes water as an emulsion, and the aggregate is no larsier than 5 mm in maximum dimension.

4. A material according to claim 2, characterised in that that rubberised bitumen comprises at least 10% rubber and the aggregate is no larger than 25 mm in maximum dimension.

5. A material according to claim 3 or 4, characterised in that the aggregate has a maximum size in the range of 3 to 5 mm.

6. A material according to any preceding claim, wherein the fibres are approximately 30 mm long.

7. A material according to any preceding claim, which comprises approximately 50% by weight rubberised bitumen.

8. A material according to any preceding claim, which comprises up to 5% by weight glass fibre.

9. A material according to claim 8, characterised in that it comprises from 0.5 to 1.5%, preferably approximately 1%, by weight, glass fibre.

10. A material according to any preceding claim, characterised in that the rubberised bitumen also comprises a fine grained filler.

11. A method of repairing or surfacing roads, parking areas and other load bearing areas in which a hot rubberised bitumen is applied to the area, characterised in that the rubberised bitumen has aggregate and chopped glass or other fibres mixed therewith.

12. A method according to claim 11, characterised in that the material applied is in accordance with claim 3, and in that the material is laid as a continuous slurry layer of up to approximately 5 mm thick.

13. A method according to claim 11, characterised in that the material applied is in accordance with claim 4, characterised in that the material is applied hot to a localised cracked, chipped and/or joint areas and a further surface layer is applied over the area to be repaired, including both said localised areas and the remainder of the area to which said material has not been applied.

14. A method according to claim 13, characterised in that the further surface layer is a black top overlay of at least 50 mm thickness.

15. A method according to claim 13, characterised in that the further surface layer comprises a bitumenous layer strengthened with glass or other fibres and provided with a surface layer of chippings or the like.