GB2065203A

GB2065203A - Flexible road surfacing

Info

Publication number: GB2065203A
Application number: GB8039138A
Authority: GB
Original assignee: ADVANCED SEALANTS Ltd
Current assignee: ADVANCED SEALANTS Ltd
Priority date: 1979-12-17
Filing date: 1980-12-05
Publication date: 1981-06-24
Also published as: GB2065203B

Abstract

The gap between bridge deck members (1, 2) is caulked with a polyethylene strip (4); the bottom and sides of the gap are coated with coatings (5, 6) of adhesion promoting material; an aluminium alloy sheet (7) is pressed into the coating on the bottom of the gap in the wearing course; and a plurality of courses is laid successively in the gap in the wearing course, each course being formed by applying a layer of hot, relatively large stones (8, 10) across the gap, pouring molten bituminous binder on to the layer and sprinkling hot, relatively small stones (9, 11) so that the interstices between the large stones are filled, the course then being compacted while still hot. The surfacing is levelled using molten bituminous binder with small stones (12) sprinkled thereon. <IMAGE>

Description

SPECIFICATION Flexible surfacing According to one aspect of the present invention, there is provided a flexible surfacing, the surfacing comprising at least one course, in which surfacing the or each course comprises a layer consisting of relatively large stones, interstices between the relatively large stones being substantially filled with a mixture consisting of a flexible binder and relatively small stones.

According to another aspect of the present invention, there is provided a method of providing a flexible surfacing, which method includes the laying of at least one course, the or each course being laid by providing a layer consisting of relatively large stones, interstices between which are substantially filled with a mixture consisting of a flexible binder and relatively small stones.

Such a surfacing could for example be, for resisting deformation, over an area of a carriageway, a footpath, an airstrip, a building, or a bridge. Alternatively, the surfacing could be in a gap, for example as a repair of a pothole, a defective area in existing surfacing, or in a reinstatement trench. It will be appreciated that the surfacing could have a single such course, for example when dealing with areas subject to skidding, such as steep ramps leading to multistorey car parks, or weaving points on roundabouts.

In the or each course, the mixture could be provided in the interstices by pouring the binder on to the relatively large stones and thereafter applying the relatively small stones; or by applying the relatively large and small stones together as a mixture and then pouring on the binder; or by pouring a combined mixture of the relatively large and small stones and the binder; or by applying the relatively small stones to the relatively large stones and thereafter pouring the binder on to the relatively large and small stones; or by pouring some of the binder on to the relatively large stones and then applying some of the relatively small stones and so on; or by applying some of the relatively small stones to the relatively large stones and then pouring some of the binder and so on; or by pouring on to the relatively large stones a mixture of the binder and the relatively small stones.

Where the surfacing is provided in a gap, before laying the course or courses, adhesion promoting material could be applied to the sides of the gap.

Also, before laying the course or courses, adhesion promoting material could be applied to the bottom of the gap. The surfacing could be in a gap on a bridge, the gap being above the opposite edges of first and second bridge deck members of the bridge. In this case, before laying the course or courses, a flexible sheet could be laid on the bottom of the gap, above the said edges of the bridge deck members. A gap between the said edges of the bridge deck members could be caulked with flexible material such as plastics material.

The surfacing could be levelled using such binder poured on to the top of the course or courses. Relatively small stones could then be spread on to the binder used for levelling the surfacing.

Preferably, the or each course is compacted after it has been laid. Also, preferably the course or the top course is heated after it has been laid.

Preferably, the binder includes elastomeric material such as rubber and/or a liquid polymer.

The present invention will now be described by way of example with reference to the single figure of the accompanying drawing, which is a longitudinal section through a joint in a carriageway on a bridge.

On a bridge having first and second concrete bridge deck members 1 and 2, there is a carriageway comprising a bituminous wearing course 3, which could be asphalt. A method will now be described for providing or replacing a flexible surfacing in the wearing course 3 above the gap between the bridge deck members 1 and 2, to accommodate relative movement of the members 1 and 2.

First, the width of the desired surfacing is marked out on the wearing course by means of straight lines across its width, the lines being on respective sides of and substantially equal distances from the gap between the bridge deck members. If an existing surfacing is being replaced, it must be ensured that these lines are beyond the edges of the existing surfacing and where the wearing course is structurally sound.A gap in the wearing course 3, above, wider than and overlapping symmetrically the gap between the bridge deck members 1 and 2, is then provided by saw-cutting vertically down from the lines to the upper surfaces of the concrete bridge deck members 1 and 2; excavating and removing the material from between the saw-cuts; cleaningout any existing jointing between the bridge deck members; and sweeping-out and air-blasting away fine material from the excavated area, particularly from between the bridge deck members, any loose or fractured material being removed. The excavated area is then thoroughly dried and warmed by an infra-red heater or other means.

A caulking strip 4 of polyethylene material is pressed into the gap between the bridge deck members 1 and 2 until the upper surface of the caulking strip is below the upper surfaces of the bridge deck members.

From now on, it is considered advisable that not more than half of the gap in the wearing course in a direction across the width of the wearing course be treated at a time. The upper surfaces of the bridge deck members 1 and 2 in the gap in the wearing course 3 are painted with a coating 5 of a concrete primer, which is a volatile solution containing latex. Also, the cut edges of the wearing course are painted with coatings 6 of the molten binder. If the wearing course 3 is concrete rather than bituminous, then the cut edges thereof will be painted instead with coatings of the concrete primer. The purpose of the coatings 5 and 6 is to promote adhesion to the existing materials and to make the surfacing to be laid waterproof.A flexible aluminium alloy sheet 7 is pressed down into the coating 5 symmetrically above the gap between the bridge deck members 1 and 2, along that part of the gap in the wearing course which is being treated. The sheet 7 could instead be rubber or neoprene. Then, a single layer of hot, closely packed, relatively large stones 8 is laid down across the width of the gap on top of the coating 5 and the sheet 7. More of the hot, molten bituminous binder is then poured on top of the stones 8 and hot, relatively small stones 9 are then sprinkled so that the result is that the interstices between the stones 8 are substantially filled with a mixture consisting of the binder and the relatively small stones, particular care being taken at corners and edges. To reduce subsequent deformation, the course thus laid is compacted while still hot.A further single layer of hot, closely packed, relatively large stones 10 is then laid down on top of the first course which has been laid, more of the hot, molten bituminous binder is poured on top of the second layer and hot, relatively small stones 11 are sprinkled as before so that the interstices between the stones 10 are substantially filled with a mixture consisting of the binder and the relatively small stones 11, with subsequent compaction of the course thus laid while still hot. The procedure is repeated until the area which is being treated is substantially full. In the figure, it will be seen that three courses of stone and bituminous binder have been laid by way of example.We have found that because of the elastic and viscous nature of the binder, which quickly solidifies as it cools and prevents ingress of further stone, even when hot, that applying heat to the surface of the top course after it has been laid, with an infra-red heater or other means, produces a very beneficial surfacing. It has the further advantage that, in the top course, it "burns off" excess binder and assists bonding of the material to the existing adjacent areas.

After the gap in the wearing course has been filled to provide the surfacing, any depressions in the upper surface of the filling are topped-up with more of the hot, molten bituminous binder and a straight edge used to get a level surface. Then, relatively small stones 12 or fine aggregate, e.g.

dust, are spread over the upper surface of the filling to cover substantially all the upper surface of the bituminous binder, and the completed surfacing is rolled or tamped so that it is substantially flush with the wearing course 3, surplus stones being swept up when the surfacing is cool. The stones 12 may be stones pre-coated with bitumen, as may the stones 9, 11 and/or 8, 10.

In each of the courses, instead of pouring the molten binder and then sprinkling the relatively small stones, the large and small stones could be applied together as a mixture and then the molten binder poured on; or the small stones could be applied first into the interstices between the relatively large stones and then the molten binder poured on; or a mixture of the binder and the relatively small stones could be poured on to the relatively large stones; or some of the binder could be poured and then some of the relatively small stones sprinkled, and so on; or some of the relatively small stones could be applied and then some of the binder poured, and so on; or a combined hot mixture of the relatively large and small stones and the molten binder could be poured.

Some typical dimensions and materials are as follows.

Depth of wearing course, 64 mm.

Width of the gap cut in the wearing course, 500 mm.

Width of the gap between the bridge deck members, 25 mm.

Width of caulking strip, 25 mm or more.

Depth of caulking strip, 38 mm.

Distance of the top of caulking strip below the upper surfaces of the bridge deck members, approximately 5 mm.

Depth of the coating 5, approximately 2 to 3 mm.

Aluminium alloy sheet, 0.5 mm gauge, 125 mm wide.

The relatively large stones 8, 10 nominally 20 mm size stones.

The relatively small stones 9, 11, 12, nominally 6 to 7 mm size stones.

The bituminous binder - a bituminous binder containing elastomeric material such as rubber and/or a liquid polymer, which binder has a softening point not less than 80 C and preferably not less than 900C and not greater than 1000C.

The binder could also include refined lake asphalt.

Preferably, in the filling comprising the courses of stone and bituminous binder, the relatively large stones constitute approximately 49% of the weight, the relatively small stones constitute approximately 22% of the weight and the bituminous binder (together with its additives) constitutes the balance, namely approximately 29% of the weight.

Claims

1. A method providing a flexible surfacing, which method includes the laying of at least one course, the or each course being laid by providing a layer consisting of relatively large stones, interstices between which are substantially filled with a mixture consisting of a flexible binder and relatively small stones.

2. A method according to claim 1, wherein the or each course is laid by applying the layer of the relatively large stones and then substantially filling the interstices therebetween with the said mixture.

3. A method according to claim 2, wherein, in the or each course, the said mixture is provided in the interstices by pouring the binder on to the relatively large stones and thereafter applying the relatively small stones.

4. A method according to claim 2, wherein, in the or each course, the said mixture is provided in the interstices by applying the relatively small stones and thereafter pouring the binder on to the relatively large and small stones.

5. A method according to claim 2, wherein, in the or each course, the said mixture is provided in the interstices by pouring some of the binder and then applying some of the relatively small stones, and so on.

6. A method according to claim 2, wherein, in the or each course, the said mixture is provided in the interstices by applying some of the relatively small stones and then pouring some of the binder, and so on.

7. A method according to claim 2, wherein, in the or each course, the said mixture is provided in the interstices by pouring a mixture of the binder and the relatively small stones on to the relatively large stones.

8. A method according to claim 1, wherein the or each course is laid by applying the relatively large and small stones together as a mixture and then pouring on the binder.

9. A method according to claim 1, wherein the or each course is laid by pouring the relatively large and small stones and the binder as a combined mixture.

10. A method according to any preceding claim, wherein a plurality of such courses is laid one on top of another.

1 A method according to any preceding claim, wherein the or each course is laid in a gap.

12. A method according to claim 1 wherein, before laying the course or courses, adhesion promoting material is applied to the sides of the gap.

13. A method according to claim 11 or 12, wherein, before laying the course or courses, adhesion promoting material is applied to the bottom of the gap.

14. A method according to any of claims 11 to 13, wherein the surfacing is on a bridge, the gap being above the opposite edges of first and second bridge deck members of the bridge.

1 5. A method according to claim 14, wherein, before laying the course or courses, a flexible sheet is laid on the bottom of the gap, above the said edges of the bridge deck members.

16. A method according to claims 13, 14 and 15, wherein the sheet is laid on to the adhesion promoting material applied to the bottom of the gap.

17. A method according to any of claims 14 to 1 6, wherein a gap between the edges of the bridge deck members is caulked with flexible material.

18. A method according to claim 17, wherein the flexible material is plastics material.

19. A method according to any of claims 11 to 18, wherein the gap is formed by cutting out material from a carriageway to form this gap.

20. A method according to claim 19, as dependent on any of claims 14 to 19, wherein the gap is formed by cutting out material from a carriageway on the bridge to reveal the bridge deck members.

21. A method according to any of claims 11 to 20, wherein the gap is in a wearing course of a carriageway.

22. A method according to any preceding claim, wherein the surfacing is levelled using such binder poured on to the top of the course or courses.

23. A method according to claim 22, wherein relatively small stones are spread on to the binder used for levelling the surfacing.

24. A method according to any preceding claim, including the step of compacting the or each course after it has been laid.

25. A method according to any preceding claim, wherein the binder includes elastomeric material.

26. A method according to any preceding claim, wherein the binder is a bituminous binder.

27. A method according to any preceding claim, wherein, in the or each course, the relatively large and small stones are applied hot.

28. A method according to any preceding claim, wherein the course or the top course is heated after it has been laid.

29. A method of providing a flexible surfacing, substantially as hereinbefore described with reference to the single figure of the accompanying drawing.

30. A flexible surfacing, the surfacing comprising at least one course, in which surfacing the or each course comprises a layer consisting of relatively large stones, interstices between the relatively large stones being substantially filled with a mixture consisting of a flexible binder and relatively small stones.

31. A surfacing according to claim 30, wherein there is a plurality of such courses, laid one on top of another.

32. A surfacing according to claim 31, wherein the surfacing has been laid in a gap.

33. A surfacing according to claim 32, wherein there is a coating of adhesion promoting material on the sides of the gap.

34. A surfacing according to claim 32 or 33, wherein there is a coating of adhesion promoting material on the bottom of the gap.

35. A surfacing according to any of claims 32 to 34, wherein the surfacing is on a bridge, the gap being above the opposite edges of first and second bridge deck members of the bridge.

36. A surfacing according to claim 35, wherein there is a flexible sheet laid on the bottom of the gap, above the said edges of the bridge deck members.

37. A joint according to claims 34,35 and 36, wherein the sheet is laid on to the coating of adhesion promoting material on the bottom of the gap.

38. A surfacing according to any of claims 35 to 37, wherein there is a caulking of flexible material in a gap between the edges of the bridge deck members.

39. A surfacing according to claim 38, wherein the flexible material is plastics material.

40. A surfacing according to any of claims 32 to 39, wherein the gap is a gap in a wearing course of a carriageway.

41. A surfacing according to any of claims 30 to 40, wherein on top of the course or courses there is applied such binder for levelling the surfacing.

42. A surfacing according to claim 41, wherein there are relatively small stones in the binder on top of the course or courses.

43. A surfacing according to any of claims 30 to 42, wherein the binder includes elastomeric material.

44. A surfacing according to any of claims 30 to 43, wherein the binder is a bituminous binder.

45. A flexible surfacing, substantially as herein described with reference to the single figure of the accompanying drawing.