GB2215370A

GB2215370A - Method of repairing or surfacing roads and the like

Info

Publication number: GB2215370A
Application number: GB8805701A
Authority: GB
Inventors: James Mcintosh; Ronald James Goodenough
Original assignee: FIBREDEC Ltd
Current assignee: FIBREDEC Ltd
Priority date: 1988-03-10
Filing date: 1988-03-10
Publication date: 1989-09-20
Also published as: GB8805701D0

Abstract

A method of repairing roads and other areas in which the entire surface area or a localised area to be repaired is provided with a surface layer of macadam in which chopped glass or other fibres are mixed before laying. Preferably, two courses of macadam are applied to a foundation base with the upper course only being strengthened by the addition of the glass fibres. The provision of the glass fibres provides a tensile strength which helps to prevent cracking passing down from the top of the upper surface into the road or other load bearing area, particularly under high loading conditions. <IMAGE>

Description

METHOD OF REPAIRING OR SURFACING ROADS AND THE LIKE This invention relates to an improved method of repairing or surfacing roads, parking areas and other load bearing areas. For example, the method may be applied to aircraft pavements and runways, roads and motorways. It may also be used on lighter duty locations, such as paths and footpaths although its primary advantage is where it is subject to heavy loading and wear.

In particular, undue wear often occurs where heavy traffic goes over a heavily cambered or other convex surface and also difficulties arise in airfields and motorways where, across the width of a track or carriageway, the main traffic is applied over a localised area, for example at the touchdown area of a runway or along the inner lane of a motorway, heavy traffic loading continually on the same locations causing undue localised wear at just those points where later patching would be very difficult because of the wear incurred. On motorway carriageways, this problem is known as tracking, that is localised tracks are formed by dished or concave tracks being formed in the inner lane.Also, problems arise where roads have been repaired, particularly where reinstated after trenches have been dug for the laying or repair of utilities, in that the material in the trench has not been so well consolidated as the surrounding main area of roadway. In such a situation, whilst the road surface initially may be reinstated to have a smooth flat transition from the repair surface to the adjacent original surface, after a relatively short period of use there would be a tendency for the reinstated area to sink with consequent damage to the road surface.

The present invention helps to overcome these problems by adding to the tensile strength of the upper surface of the road such that it is far less likely to crack and break up, the surface being more resistent to distortions such that it is less likely to dish or become displaced under heavy loading conditions, and also it is less likely that cracks will be transmitted from the upper surface down through the surface layer.

According to the invention, there is provided a method of surfacing or repairing roads, parking areas and other load bearing areas in which a surface layer of macadam is applied, chopped glass or other fibres being mixed in the macadam before it is laid.

Preferably, two layers of macadam are applied to a foundation base, these layers comprising a base course and a wearing upper course with the fibres preferably being added to the wearing course macadam only. The macadam comprises bitumen and stone filler and normally the particle size of the filler in the base course can be expected to be larger than that of the filler in the wearing course with the particle size in the filler of the base course by way of example being up to 20 mm maximum dimension and the particle size of the filler in the wearing course being up to 6 mm in maximum dimension.

Clearly, the particular dimensions of the filler used in the macadam will vary depending upon the specific requirements of a particular location in accordance with normal practice, the provision of the fibres being additional in order to increase the tensile strength and resistance to deformation of the macadam once it has been laid in situ.

Depending upon the requirements of a particular site, the fibre reinforced macadam may be applied as a surface over the entire area being surfaced or it may be applied over a localised area being repaired. In particular, the surface of the present invention is useful to fill the upper part of a reinstated area of a road, for example, where a trench has been dug for the laying or repair of utility services.

A further aspect of the invention provides the fibre reinforced macadam itself which suitably may comprise 7 to 20% bitumen and normally up to 1% glass fibre, by weight, although other percentages may be used in special circumstances, the balance being stone aggregate filler.

In the normal surface application where one is applying a wearing course over a base course of macadam, the layer of macadam will vary depending upon the particular situation of use. For example, on a relatively light loaded estate road, the thickness of the macadam layer may be 60 mm while on a motorway the thickness of macadam may be 100 to 150 or even as much as 200 mm. The thicknesses of the layers will depend upon the particular circumstances but under average conditions, one can expect the wearing course to be from 20 to 50 mm thick and the base course to be from 40 to 150 mm thick.

Whilst glass fibres are preferred, other fibrous material is usable, a particular example being chopped polypropylene fibres. In a particularly advantageous method, where one is resurfacing a somewhat damaged foundation base, it can be preferred and convenient to patch and repair the foundation base with a rubberised bitumen reinforced with aggregate and including chopped glass or other fibres in order to prevent reflected cracks being passed from the foundation to the covering layer of macadam. Such a material is specifically disclosed in our co-pending Application No 87 02289.

Claims

1. A method of surfacing or repairing roads, parking areas and other load bearing areas in which a surface layer of macadam is applied, chopped glass or other fibres being mixed in the macadam before it is laid.

2. A method according to claim 1, wherein two layers of macadam are applied to a foundation base, a base course and an upper wearing course.

3. A method according to claim 2, wherein the fibres are added to the wearing course macadam only.

4. A method according to claim 2 or 3, wherein the macadam comprises bitumen and stone filler, the particle size of the filler in the base course being larger than that of the filler in the wearing course.

5. A method according to claim 4, wherein the particle size of the filler in the base course is up to 20 mm maximum dimension.

6. A method according to claim 4 or 5, wherein the particle size of the filler in the wearing course is up to 6 mm maximum dimension.

7. A method according to any preceding claim, wherein the fibre reinforced macadam is applied as a surface over an entire area being surfaced.

8. A method of surfacing or repairing roads, parking areas and other load bearing areas substantially as hereinbefore described.

8. A method according to claim 7, wherein the area being covered is cambered.

9. A method according to any one of claims 1 to 6, wherein the fibre reinforced macadam is applied over a localised area being repaired.

10. A method according to claim 9, wherein the fibre reinforced macadam is used to fill the upper part of a reinstated area of a road or the like.

11. A method according to any preceding claim, wherein the surface layer is applied over a foundation base which itself has been repaired using localised areas of rubberised bitumen containing filler and chopped glass or other fibres.

12. A method of surfacing or repairing roads, parking areas and other load bearing areas substantially as hereinbefore described.

13. A material for surfacing or repairing roads, parking areas and other load bearing areas, which comprises macadam of which the major constituent is stone aggregate filler together with a bitumen matrix and with chopped glass or other fibres mixed therein.

14. A material according to claim 13, which comprises between 7 and 20% bitumen and less than 1% by weight glass fibre, the balance being stone aggregate filler.

Amendments to the claims have been filed as follows

1. A method of surfacing or repairing roads, parking areas and other load bearing areas in which a base course and an upper wearing course are applied as two layers of macadam to a foundation base, chopped glass or other fibres being mixed in the macadam before it is laid as the upper wearing course, the macadam comprising bitumen and stone filler, the particle size of the filler in the base course being larger than that of the filler in the wearing course and the particle size of the filler in the wearing course being of up to 6 mm maximum dimension.

2. A method according to claim 1, wherein the particle size of the filler in the base course is of up to 20 mm maximum dimension.

3. A method according to any preceding claim, wherein the fibre reinforced macadam is applied as a surface over an entire area being surfaced.

4. A method according to claim 3, wherein the area being covered is cambered.

5. A method according to claim 1, wherein the fibre reinforced macadam is applied over a localised area being repaired.

6. A method according to claim 5, wherein the fibre reinforced macadam is used to fill the upper part of a reinstated area of a road or the like.

7. A method according to any preceding claim, wherein the surface layer is applied over a foundation base which itself has been repaired using localised areas of rubberised bitumen containing filler and chopped glass or other fibres.