GB2147908A

GB2147908A - Bituminous surfacing material

Info

Publication number: GB2147908A
Application number: GB08425719A
Authority: GB
Inventors: Samuel James Peden
Original assignee: Maxwell R J
Current assignee: Maxwell R J
Priority date: 1983-10-11
Filing date: 1984-10-11
Publication date: 1985-05-22

Abstract

A bituminous surfacing material for example for tennis courts comprises a mixture including an aggregate of stone of different size gradings varying between 0 and 10 mm and a bituminous binder with a polymer additive and a limestone filler. The playing surface so formed will be of porous open textured form providing a uniformly free drainage characteristic over the entire playing surface, and the surface will provide a highly responsive playing surface.

Description

SPECIFICATION Bituminous surfacing material The present invention relates to bituminous surfacing material and more particularly to bituminous macadam surfacing material. The material of the present invention is especially intended for use in the formation of a playing surface, such as for example a tennis court.

It is desirable for a playing surface such as a tennis court to have satisfactory drainage characteristics and material used in the surfacing should conveniently enable the surfacing to be laid to a high standard of level tolerance.

It is an object of the present invention to provide a bituminous surfacing material enabling the construction of an improved playing surface meeting the above requirements.

According to the present invention a macadam surface material for the formation of a porous open textured surface comprises a mixture including an aggregate of stone of different size gradings, varying between 0 and 10 mm, and a bituminous binder with a polymer additive.

Preferably, at least three size gradings of stone are used in the 0 to 10 mm range.

In one preferred embodiment the aggregate comprises gradings of 100 percent passing 10 mm stone; 85 100 percent passing 6.3 mm stone; 15 - 35 percent passing 3.35 mm stone; 5 - 15 percent passing 1.18 mm stone and 0 - 5 percent passing .075 mm stone, all by weight; with 4.5 - 5 percent bitumen binder with a tolerance of plus or minus 0.5 percent.

A preferred specific aggregate is as follows:10 mm stone - 100 percent passing by weight 6.3 mm stone - 92 percent passing by weight 3.35 mm stone - 25 percent passing by weight 1.18 mm stone - 10 percent passing by weight 0.075 mm stone - 4 percent passing by weight Differing proportions of dust may be used in the aggregate to give different surface porosities; a preferred blend proportion being 20% dust to 80% stone.

Preferably, hydrated limestone is added to the stone aggregate as a filler. The polymer can amount to 5% by weight of the binder and the hydrated limestone may comprise 1% of the total aggregate weight.

In a preferred method of laying a surface using the above bituminous macadam material, a pair of longitudinal runners are used supporting a travelling screed which serves to level the material.

The present invention is also a surface made from the above material according to the present invention.

In an embodiment of the present invention, now described by way of example, a bituminous tar macadam material is provided especially for use in the construction of playing surfaces such as tennis courts. It is a feature of the material that the playing surface formed therefrom is of porous open textured form and the surface will have the following characteristics: a) uniformly free drainage over the entire surface; b) the provision of a highly responsive playing surface; and c) a high standard of tolerance of deviation from the level.

The tarmacadam material of this embodiment has a specification characterised by the presence of stone with a plurality of different size gradings, and in particular at least three stone gradings are present and preferably five. The gradings are in the range 0 - 10 mm (to give a nominal 6 mm specification), and in this case a suitable aggregate specification (determined by passing through sieves whose mesh determines the size gradings) is as follows: Example 1 10 mm stone - 100 percent passing by weight 6.3 mm stone - 85 - 100 percent passing by weight 3.35 mmstone- 15- 35 percent passing by weight 1.18 mm stone 5- 15 percent passing byweight 0.075 mm stone - 0 - 0 percent passing by weight A bitumen binder is used of 4.5 - 5.5 percent with a polymer additive. The above percentages have a tolerance of plus or minus 0.5 percent.

A suitable amount of dust is included in the blend to provide a desired porosity in the surface, and by way of example an aggregate blend would be 80% stone (6 mm nominal) and 20% dust.

The precise blending of the mix could be settled by laboratory testing to give the above listed surface characteristics but a resultant aggregate blending would be: Example 2 10 mm stone 100 percent passing by weight 6.3 mm stone - 92 percent passing by weight 3.35 mm stone - 25 percent passing by weight 1.18 mm stone - 10 percent passing by weight 0.075 mm stone - 4 percent passing by weight The aggregates used in the mix are preferably selected from a source so as to comply with the following requirements: Aggregate crushing value - less than 30% Polished Stone Value (P.S.V.) - more than 55% Water absorption - less than 2% Flakiness index - less than 18% Specific gravity - more than 2.500 200 penetration grade bitumen to B.S. 3690 (British Standards) is used as the binder added at a rate of 5% by weight of the mix.

Hydrated limestone filler is added to the mix: this addition ensures greater ease of stone coating and will ensure that each stone is coated with bitumen. The limestone filler must form at least 1% of the total aggregate weight.

The polymer is an Ethylene Vinyl Acetate (E.V.A.) and is added to the mix at a rate of 5% by weight of the bitumen binder. A suitable additive is Esconene Ultra E.V.A. polymer with properties as follows - Hot Melt Grade E.V.A. polymer UL 53019CC. Table A set out below lists the properties of hot melt grades E.V.A.

polymers. The addition of the polymer improves the flexibility of the bituminous macadam material such that the material handling is made easier at a lower temperature. Additionally, the polymer gives increased resistance to softening of the bitumen during high summer temperatures so that the playing surface will be suitable for use in these climatic conditions.

Porosity testing can be carried out to determine a suitable dust content for the mix; Moulds shall be manufactured of a trial mixture and the voids shall be determined by weighing in air and water and the density calculated against a theoretical density determined from known specific gravity values of the constituents. The voids in the mixture shall be in the range 17 to 25 percent by volume.

TABLE A Properties Measurement UL 53019 CC VA ESSOCHEM 19 INCORPORATION PLASTICS % BYWEIGHT INC.

MELT INDEX, ASTM 530 g/10 min (1) D1238 MELTFLOW ASTM 12.1 A RATE D1238 g/10 min (2) DENSITY, ASTM 0.934 g/cm3 D792 TENSILE ASTM 285 AT BREAK, D638 N/cm2(3) ELONGATION ASTM 200 AT BREAK, % D638 1% SECANT ASTM 2000 MODULUS D638 N/cm2 HARDNESS ASTM 84 SHORE A D2240 RING AND BALL ASTM 87 SOFTENING E28 POINT, "C BROOKFIELD ESSOCHEM 20 VISCOSITY PLASTICS mPa.s(4) INC.

The macadam material is formed by mixing at a suitable temperature of between 1500 - 190"the constituent parts aforementioned for a period of not less than 60 seconds and not more than 90 seconds. In the formation of a playing surface using the above macadam material of the present invention, a pair of parallel longitudinal steel runners can be used extending along the length of the playing surface and the material of the surface is levelled using a travelling screed supported by the runners. The macadam material can be worked and laid to very fine tolerances so as to ensure that the level deviation when checked with a 3 m steel straight edge is within the range + or - 3 mm.

The playing surface so formed will be of porous open textured form providing a uniformly free drainage characteristic over the entire playing surface, and the surface will provide a highly responsive playing surface.

Claims

1. A macadam surface material for the formation of a porous open textured surface comprising a mixture including an aggregate of stone of different size gradings, varying between 0 and 10 mm, and a bituminous binderwith a polymer additive.

2. Material as claimed in Claim 1, wherein at least three size gradings of stone are used in the 0 to 10 mm range.

3. Material as claimed in Claim 2, wherein the aggregate comprises gradings of 100 percent passing 10 mm stone; 85 - 100 percent passing 6.3 mm stone; 15 - 35 percent passing 3.35 mm stone; 5 - 15 percent passing 1.18 mm stone and 0.5 percent passing .075 mm stone, all by weight; with 4.5 - 5 percent bitumen binder with a tolerance of plus or minus 0.5 percent.

4. Material as claimed in Claim 2 or 3 wherein proportions of dust are used in the aggregate to give different surface porosities.

5. Material as claimed in Claim 4, wherein the proportion is 20% dust to 80% stone.

6. Material as claimed in any one of the preceding Claims wherein hydrated limestone is added to the stone aggregate as a filler.

7. Material as claimed in any one of the preceding Claims wherein the polymer is in the proportion of 5% by weight of the binder.

8. Material as claimed in Claim 6 or7,wherein the hydrated limestone is 1% ofthetotal aggregate weight.

9. A surface when made from the material substantially as hereinbefore described with reference to the example.

10. A material substantially as hereinbefore described with reference to the Examples.