AU606976B2

AU606976B2 - Road repair

Info

Publication number: AU606976B2
Application number: AU20149/88A
Authority: AU
Inventors: Adrian Oloff Bergh; Hugh Clelland Thompson
Original assignee: Petrocol Pty Ltd
Current assignee: Petrocol Pty Ltd
Priority date: 1988-07-28
Filing date: 1988-07-28
Publication date: 1991-02-21
Anticipated expiration: 2008-07-28
Also published as: AU2014988A

Description

1 ir--

COMMONWEALTH

0 F A U T A I PATENT ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

-0976 FOR OFFICE USE CLASS INT. CLASS Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art-: Jf].mu~t1dlcrd; "rck urnoe 7 rr1.ccrrrt r,, jj d NAME OF APPLICANT: ADDRESS OF APPLICANT: NAME(S) OF INVENTOR(S) ADDRESS FOR SERVICE: ADRIAN OLOFF BERGH, HUGH CLELLAND THOMPSON AND FREYSSINET S.A. (PROPRIETARY) LIMITED 11 Glyn Street, Colbyn, Pretoria, Transvaal Province; 19A Amelia Street, Dunvegan, Edendale, Transvaal Province; and 301 Argent House, 21 Loveday Street South, Johannesburg, Transvaal Province; respectively.

All of Republic of South Africa Adrian Oloff BERGH Hugh Clelland THOMPSON DAVIES COLLISON, Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: "ROAD REPAIR" The following statement is a full description of this invention, including the best method of performing it known to us -1i, (a member of the firm of DAVIES COLLISON for and on behalf of the Applicant).

To: THE COMMISSIONER OF PATENTS Davies Collison, Melbourne and Canberra.

i I^ IXiCUs~l---~I---I -2- THIS INVENTION relates to road repair, particularly to the repair of hard top roads, such as black top or concrete roads.

The surfaces of such roads on occasion deteriorate by cracking or crumbling in parts. Repair of such roads by conventional methods usually takes a relatively long time requiring diversion of traffic during the period while repairs are being made. The Applicant is also aware of patches being used to repair cracked parts of a road. However such patches are not easily transportable because of their mass and size.

C CC C CCC It is an object of this invention to provide the applicants believe will be more transportable than road repair patches known a road repair patch which easily manhandled and to them.

tC I t I I C C s i-i i i 1 I:-i

:-I

I- i' Ar rdingly the invention provides a prefabricated road patch which includes a flexible backing sheet comprising a flexible reinforcing mesh material sandwiched with a road surface binder material between two layers of paper; and a layer of aggregate held by a layer of road surface binder material to one surface of the flexible backing sheet.

The flexible backing sheet may have perforations spread over its surface. The flexible reinforcing mesh material may be made of twine, string, heat-resistant synthetic plastics fibre, or the like.

The layer of road surface binder material may be a bitumen rubber having a thickness corresponding to an application rate lying in the i I- Y qTI -3range between 12 liters to 3 liters per square meter. The thickness of aggregate may correspond to an application rate lying in the range of fi 5 to 13 liters per square meter.

fl. The invention extends also to a method of making a prefabricated road repair patch as described, which includes jreleasably securing a flexible backing sheet to a working platform, the flexible backing sheet including a flexible reinforcing two layers of paper; i .applying a bitumen rubber binder layer to the upper surface of the flexible backing sheet at a rate lying in the range l liters to 3 liters per square meter; spreading aggregate on to the bitumen rubber, coated upper surface S of the flexible backing sheet; then rolling the thus spread aggregate onto the flexible backing sheet by a heavy roller; and then removing the product comprising the flexible backing sheet with adhering bitumen rubber binder and aggregate from the working platform, and if necessary cutting the said product into patches of ji l the required size.

I ,The working platform may be in the form of a platen which is heated.

iI The temperature at which the bitumen rubber binder is applied to the I upper surface of the flexible backing sheet, may be in the range between 170 0 C and 2100C.

The edges of the flexible backing sheet material may be masked by .!template means, and the thickness of the bitumen rubber binder may be determined by the thickness of the template means.

The aggregate may be precoated with a tar base binder before spreading it onto the bitumen coated upper surface of the flexible backing sheet.

Instead of paper, the flexible backing sheet may be made of a synthetic geofabric material.

_i 1 -4- The aggregate used may be one of any four nominal sizes, used singly or in combination in any desired proportion.

The four nominal sizes of aggregate will be referred as the 6mn, 91nm, 13mm and 19mm sizes. This comprises stones having the following grading: Sieve Aggregate Passing by Mass Size mm Nominal Size 6mm Nominal Size 9mm Nominal Size Nominal Size 13mm 19mm

PI

4 4? 44 4 4 44 26,5 19,0 13,2 6,7 4,75 3,35 -0,425 100 85 100 0 30 0 0,7 100 85 100 0 30 0 0,7 100 85 100 0 30 0 0,7 100 85 100 0 0 0,7 Aggregate Spread Rate m 3 /m 2 0,005 0,007 0,010 0,013 i 4 1 3 4 4 44l i :j Bitumen Rubber Spread Rate e/m 2 1,4 1,8 1,8 2,3 1,8 2,6 2,4 The adhesive for .adhesivly securing the aggregate to the flexible sheet of backing material, may be bitumen rubber. Any one of the three grades of bitumen 150 200 Pen. Bitumen, 80- 100 Pen. Bitumen or 60-70 Pen. Bitumen may be used. The rubber content may be at least 1/5th by mass but can be 1/4 or even 1/3 or more, depending upon cost and economic feasibility.

i- _1 i 4; I I A diluent of hydrocarbon distillate may be added to improve the workability of the bitumen rubber blend.

The blended bitumen rubber may have a resiliency of 15% when tested in accordance with the Test Method (BR2T) and may have a maximum flow of when tested in accordance with the Test Method (BR4T).

The rubber may be obtained from granulated truck tyres or heavy duty construction plant tyres. Preferably 100% of the rubber shall pass a 1,18 mm sieve. The maximum fibre length may be 2mm. The natural rubber contents as a percentage by mass of the total hydrocarbon rubber is preferably at least S 0 Two manufacturing processes for manufacturing road repair patches may be used.

SFirst Manufacturing Process 0, 00 The flexible backing sheet is removably secured to a working platform.

The bitumen rubber is applied by means of a spray tanker at a 00 I I. temperature lying in the range of 170° (to 210 0 C by driving over the flexible backing sheet, in order to achieve a specified spray rate lying in the range of 1l liters to 3 liters per square meter. The o0 o aggregate is then applied by mechanical means or by hand, to achieve a °0 specified rate of application lying in the range of 5 liters to 13 liters per square meter. A 15 to 20 tonne roller then passes over the thus applied aggregate to ensure the firm bedding onto the flexible I backing sheet which is then released frcn the work platform, with the bitumen rubber and the aggregate adhering thereto. The product is then cut if necessary into the desired size to form the patches. The patches may then be loaded onto crates, and transported and stored Sunder cover.

Second Manufacturing Process According to this process, the working platform is in the form of a heated platen. The edges of the flexible backing sheet are marked by means of a template. The bitumen rubber is then evenly applied at a

I

-6specified spray rate as described before by means of a squeegee or by means of spray jets. The aggregate is then applied either by hand or mechanically. The aggregate is then rolled with mechanically pressurized rollers and subsequently cut to size if necessary and loaded on crates and stored under cover if desired. According to this method, the thickness of the bitumen rubber is determined by the {i thickness of the template.

The adhesive coat applied to that portion of the road surface which is o. to be repaired, also referred to as the tack coat, may be 60% anionic or cationic bitumen emulsion. The tack coat may be applied by means of a brush.

oo 00 00..0 The invention will now be described by way of example with reference o to the accompanying diagrammatic drawings.

In the drawings: o 00 FIGURE 1 shows a three dimensional view of part of a road surface o.o having a portion requiring repair; FIGURE 2 shows a three dimensional view of a flexible backing S00oo sheet for making a road repair patch in accordance with the invention; and FIGURE 3 shows a sectional elevation as at Ill-III in Figure 1, 00' when a patch as shown in Figure 3, has been applied to the portion of 0"0 road surface shown in Figure 1.

Referring to the drawings, reference numeral 10 refers generally to a road surface damaged by cracks or fissures 12 occurring in a portion 14 of the road surface 10, or in the surface of a base repair carried out using bituminous bound crushed aggregate or natural gravel.

Reference numeral 16 refers generally to a road surface repair patch which is in the position shown dotted by reference numeral 16 in Figure 1, to cover that portion of the road surface having the cracks or fissures 12. In order to secure the patch to the damaged portion of the road surface, the said portion is coated with a bitumen emulsion to provide a tack coat as shown by reference numeral 14. The 7patch is then placed onto the tack coat 14, and rolled down firmly to be held by the tack coat 14. The same procedure is used when repairing the surface of a base repair The patch includes a flexible backing sheet 18 comprising a flexible reinforcing mesh material 20 sandwiched with a binder material 18.1 between two layers of paper 18.2 and 18.3 having perforations 18.4. A layer of aggregate 24 is held by a layer 22 of bitumen rubber to the upper surface of the upper layer of paper 18.3. The bitumen rubber °on may have a content of rubber of about 30%. The layer 22 holds the stone aggregate 24, having one or more components in desired proportions. For four components, the grading may be 19mm, 13mm, 9mr O 9 and 6mm.

It is an advantage of this invention that patches 16 are light and strong and can be made or cut to any convenient size and shape. The flexible backing sheet 18 is strong enough to hold a dense but S' relatively thin layer of aggregate. The patches 16 may be in rectangular form and may be transported or carried in roll form.

Conveniently they will be made of such a size, that they can be easily carried by one person. When a large area of a road surface has to be repaired, then the repair can be carried out, by laying the patches next to one another or end on, in order to cover adequately, the o surface which is to be repaired.

0 0 0 The Applicants believe that roads of the kind described, can be repaired quickly and well without causing excessive lumps cn the road repaired.

The Applicants do not wish to be bound by theory but they believe that a good bond between patch and the existing road surface is achieved initially by the interaction between the tack coat 14, the binder material 18.1 and the bituman rubber layer 22 through the perforations 24 in the flaxible backing sheet 18. Thereafter under continued use, with traffic passing over a patch, the paper layers 18.2 and 18.3 disintegrate and the bituman rubber layer 22 with the binder material 18.1 and the tack coat material 14.

Claims

1. A prefabricated road patch which includes a flexible backing sheet comprising a flexible reinforcing mesh material sandwiched with a road surface binder material between two layers of paper; and a layer of aggregate held by a layer of road surface binder material to one surface of the flexible backing sheet.

2. A patch as claimed in Claim 1, in which the flexible backing sheet has perforations spread over its surface.

3. A patch as flexible reinforcing selected from twine, fibre. claimed in Claim 1 or Claim 2, in which the mesh material is formed of elongate elements string, or heat-resistant synthetic plastics

4. A patch as claimed in any one of Claims 1 to 3 inclusive, in which the layer of binder material is a bitumen rubber having a thickness corresponding to an application rate lying in the range between 1 liters to 3 liters per square meter; and in which the thickness of aggregate corresponds to an application rate lying in the range of 5 to 13 liters per square meter.

A method of making a prefabricated road repair patch as claimed in Claim 1, which includes releasably securing a flexible backing sheet to a working platform, the flexible backing sheet including a flexible reinforcing mesh material sandwiched with a road surface binder material between two layers of paper; applying a bitumen rubber binder layer to the upper surface of the flexible backing sheet at a rate lying in the range i liters to 3 liters per square meter; spreading aggregate on to the bitumen rubber coated upper surface of the flexible backing sheet; then rolling the thus spread aggregate onto the flexible backing sheet by a heavy roller; and then -9- removing the product comprising the flexible backing sheet with adhering bitumen rubber binder and aggregate from the working platform, and if necessary cutting the said product into patches of the required size.

6. A method as claimed in Claim 5, in which the working platform is in the form of a platen which :is heated,

7. A method as claimed in Claim 5 or Claim 6, in which the temperature at which the bitumen rubber binder is applied to the upper surface of the flexible backing sheet, lies in the range between 170 0 C and 210'C.

8. A method as claimed in claim 5, Claim 6 or Claim 7, in which the edges of the flexible backing sheet material are masked by template means; and in which the thickness of the bitumen rubber binder is determined by the thickness of the template means.

9. A method as claimed in any one of the inclusive, in which the aggregate is precoated with a before spreading it onto the bitumen coated upper flexible backing sheet.

Claims 5 to 8 tar base binder surface of the A prefabricated road repair patch, substantially as described and illustrated herein.

11. A method of making a prefabricated road substantially as described and illustrated herein. The--s~tep s--or-f eat d-s=s co s ed- re-in- e3mb.i=n-ftin--he reo f-£ repair patch, -o r- a DATED this 28th day of July, 1988 ADRIAN OLOFF BERGH, HUGH CLELLAND THOMPSON AND FREYSSINET S.A. (PROPRIETARY) LIMITED By Its Patent Attorneys DAVIES COLLISON