Improved means of securing re-purposed tyres for creating a roadway

Abstract

A method of forming the base of a roadway 200 comprises the steps of: providing a planar ground surface 10; placing in a regular pattern on the surface a plurality of tyre cylinders 30 from which the side walls have been removed; joining the tyres together using nails 70 from a nail gun; infilling the tyre cylinders and surround with an aggregate 40; and, laying a running surface 60 for traffic. Lower and upper geotextile layers 20, 50 may be placed below and above the tyres respectively. The placement of tyres and the provision of infill and an upper geotextile layer may be repeated. The nails may be applied in the direction of the intended flow of traffic. The tyre cylinders may be secured by a staple 80 placed over the edges of the tyre and penetrating the ground surface. The road surface may comprise tar macadam and concrete. The geotextile may be a thermoplastic. A base of a roadway formed from the method is also claimed.

Description

The present invention relates to the improved arrangement of re-purposed tyres for creating a roadway. Background Approximately 55 million waste tyres are created in the UK each year. The walls of the tyres may be detached and partly reused, for example by breaking down into 'crumb' for subsequent incorporation into other products or combusted to produce energy. This leaves the tyre treads, or more correctly the cylinders, here termed tyre cylinders left after a used tyre has had its tyre walls removed. These are not permitted for use in landfill and are difficult to recycle as they represent a composite of rubber, fabric and steel. It is therefore desirable that alternative uses of these cylinders may be found. Numerous uses of such waste tyres are known, for example they may be used to form the basis, when attached together, to form a road base, such as disclosed in US 5846021. The use of the tyre cylinders to form a road base is also disclosed in WO 2006 / 078485. The use of the tyre walls may also be used for a similar purpose such as disclosed in US 6457912. There are also very many disclosures for the use of used tyres to form walls, embankments and other such structures. In the first phase of such use the simple ability to find an alternative re-purpose of such waste material was sufficient and such road bases were readily adopted for forest roads, industrial areas and similar places were a quick and durable road base was required. However, now that a supply chain for recycled tyre components has been established there is a need to provide better engineering solutions so that a higher volume of waste tyre material may be effectively used. To achieve this methods of use conforming to conventional road construction techniques and requirements is needed. In particular, means to facilitate and automate the process to make it more reliable and robust are needed so as to move the use from being a niche application to more widespread use. A number of problems can arise from the straightforward laying of tyres to form 5 structures. One of the principal problems is that it is difficult to fill the structure of the tyre effectively and therefore irregular voids can be created and these can often fill with water which may stagnate and the underlying structure may be irregular. This is partly overcome by the use of tyre cylinders but these also present challenges. One problematic aspect of road construction is that on higher speed roads not only 10 must the road be resistant to abrasion and whether but also a very consistent and even surface must be created to avoid undue vibration and with it driver fatigue, vehicle maintenance and for the road constructor and maintainer additional maintenance. In addition, new forms of tyre are becoming increasingly prevalent. Whilst current 15 market penetration may be of only a few percent a few percent of 55 million still represents a very considerable amount of material. There is an ongoing need for improved use of tyre waste to facilitate the effective repurposing of used tyres. The present invention The present invention in its various aspects is as set out in the appended claims. The present invention provides a method of forming the base of a roadway, the method comprising the steps: a. providing a generally planar ground surface; b. placing over said surface an optional, lower, geotextile sheet or layer; c. placing upon said lower geotextile a plurality of tyre cylinders, being the product of vehicle tyres from which the side walls have been removed; d. wherein the tyre cylinders are laid radially on said ground or geotextile surface in a regular pattern; e. infilling said tyre cylinders and surround with a composition comprising an aggregate; optionally compacting said aggregate; f. optionally repeating steps c, d and e; g. placing over said surface an optional further, upper, geotextile sheet or layer; h. laying a running surface for traffic over said previous layers; wherein: upon placing said plurality of tyre cylinders in step c said tyres are joined together by means of nails applied using a nail gun. As disclosed in the background section, the use of tyre cylinders for the production of a roadway base is known, however such use has generally been for utility roads and temporary roads, for applications such as mining and forestry. For high speed road application a more controlled process is required. One of the key steps in the process is step e of infilling said tyre cylinders and surround with a composition comprising an aggregate and optionally compacting said aggregate. The use of the tyre cylinders constrains the aggregate, particularly when being compacted and providing high integrity road base. However, the tyre cylinders before being weighed down by the aggregate can move around and aggregate can serve to fill between the tyres and separate them giving a less homogeneous and robust construction. It is particularly desirable that each tyre bought at least two other tyres more preferably each tyre should abort for other tyres and with a close packed arrangement six tyres. This arrangement can be easily disturbed by aggregate pushing tyres apart by infill between the tyres before infill within the tyre cylinders takes place. In practice this is very difficult to undo but in utility applications some degree of unit of nonuniformity is tolerable. However this is not so in high-speed roads High-speed roads are roads on which traffic will typically travel in excess of 50 kilometres an hour, examples of such roads may be termed arterial roads or A roads, and my more importantly were in traffic will typically travel in excess of 100 kilometres per hour, examples of such roads may be termed highways, freeways, motorways or Autobahn. In such high-speed roads unevenness on the road surface can give rise to significant vibration. This can simply be an underlying oscillation but it may also give rise to resonant effects with constructive interference which may give rise to high localised vibrational forces. Whilst these forces may be localised, when hundreds of kilometres of road are being considered then the integrity of the road must be consistent and even small areas where resonant effects occur can degrade the performance of an elongate stretch of road. These effects of unevenness are limited in conventional road construction by the use of aggregates and structures which are of small size in relation to the vehicle tyres which run over them. Hence, a vehicle tyre with a radius of half a metre will be running over a particulate with maximum size in the order of at most a centimetre and usually much smaller with the underlying road surface typically also been constructed of, relatively speaking fine particulate material such as gravel. Therefore, there is a significant disparity in size and the possibility of similar frequencies being generated between tyre / wheel and road is not significant. Hence, degree for use in higher speed and quality roads the present invention provides a means were in the tyre cylinders are secured one to another. The securing of tyres in the forming of a surfaces known, such as in US 58460214 this is not normally practised since joining, as disclosed in that application by means of bolts, lag screws, dog bone clips, adhesives, solvents and vulcanising agents is time consuming, adds cost and is difficult to perform. However, in the present invention it is been found that the use of nails applied by a nail gun, that is nails which are fired at high speed is a quick and practical means to join together tyre cylinders. The nails for use in the present invention are preferably between three and 10 millimetre in diameter, more preferably between five and eight millimetres in diameter. Nails for use in the present invention preferably between 5cm and 20cm when data in length, most preferably between 10 and 15 centimetres in length. What is been found important is that a significant amount of the nail should protrude through the outgoing side of the adjoining tyre to avoid the nail becoming forced out as the elastomeric material of the tyre relaxes after fasting. Importantly, use of a nail gun is essential as if the nails are not actually fired into the tyre cylinders then they do not penetrate without pre-drilling, which is required with prior disclosures of mechanical fasteners. This is a practical reality as tyre cylinders comprise several centimetres of vulcanised rubber, three layers (at least) of steel wire and fabric reinforcement, such as nylon fabric. I fired it means that the application of the nails of the present invention are impacted upon the tyre cylinders at a velocity of at least 50 metres per second, more preferably 60 metres per second most preferably over 100 metres per second. Whilst in principle there is not an upper limit practical considerations mean that a velocity over 200 metres per second is unnecessary. The use of the nails of the present invention, as suitably applied, provides the road with greater strength and integrity not only during the infill phase with aggregate but also during prolonged use. Another feature of the present invention, optionally implemented independently of the nail fasteners are the use of staples to staple over the edges of the tyre cylinders into the aggregate and more preferably into the underlying ground. Such staples preferably comprise an elongate II - shaped wire rod. The wire of the wire rod is preferably made from rebar between 0.5 and 1.5 centimetre in diameter. Most preferably of one centimetre in diameter. The ends of the wire are preferably cut to points, or two and end resembling a point. This may be most effectively achieved by a diagonal cut of the wire; this is both simple quick cheap and effective. In a single court provides points and two ends of two pieces of wire simultaneously. The principal disadvantage and the staples is that when used on the main part of the roadway they provide protrusions above the edges of the tyre cylinders and these ‘bumps’ can perpetuate through the running surface of the road to discomfort a driver due to vibration and resonance effects. There are, however, controlled construction examples where unevenness is deliberately introduced. For example, along the edges of high-speed roads there can be formed strips of material with regular small bumps so that should a driver, such as a driver losing concentration, of falling asleep, drift over to the side of the road such strips result in a vigorous, although safe, noisy and inconvenient vibration so is to wake the driver. However, it is been found that it is sufficient to place the staples and the edges of the roadway to stop lateral spread of the tyre cylinders when being filled when used in conjunction with the nail fastenings of and applied in the method of the present invention. The staples along the edges of a further advantage that the vibration effect can act as aforementioned, to act as a warning to drivers venturing to drive on the edge of the road. In the present invention, the uppermost layer is the provision of a running surface for traffic. This may be any surface which is constructed, i.e. laid upon the base layer (the last iteration of steps c, d, e) comprising the tyre cylinders as the next layer below, or the next layer below within 5 centimetres or less, more preferably 2 centimetres or less, most preferably absent. This allows for the presence of a geotextile or light screed of sand or gravel. A thicker intermediate media layer loses the benefit of the tyre cylinders giving underlying road integrity. In the present invention, the running layer may be concrete. However, the concrete suitable for the present invention is that which is laid on site, i.e. poured and cured in situ above the road base. The use of preformed slabs of concrete placed directly over the road base, such as in the manner of paving slabs, is not within the scope of the present invention, this is because the nodes of the tyres are thereby obscured. Whilst this is not the case where the paving slabs may be small, such as in paving bricks such paving bricks are unsuitable for use in conventional, high-speed roadway and as previously mentioned the benefits of the present invention occur most were high-speed traffic (as previously defined) is present. In the present invention, the running layer may be tar macadam, preferably hot lay tar macadam which may be referred to as tarmac, asphalt, blacktop, pavement (US), asphalt (or asphaltic) concrete, bituminous asphalt concrete, and bituminous mixture. However, the common essential feature is that the material comprises a hot melt bituminous mixture in conjunction with stone aggregate. Hot lay tar macadam is typically laid at a temperature between 130 and 166°C and the use of a geotextile with said glass transition temperature (or melting point depending upon what is the correct scientific measure for a given polymer type), has the very beneficial effect that at the temperature and pressure (bearing in mind that a 10 centimetre layer of tar macadam produces a 240 kilograms a square metre pressure) causes the geotextile to bond or at least conform to the tyre waste (which as previously mentioned is preferably in the form of tyre cylinders) and therefore produces a much more stable at road base structure. That this is beneficial is evident from the prior art were the great difficulty and expense of connecting tyre waste laterally (see US 58496021) by means of nuts and bolts is considered worthwhile. An equally strong if not stronger bonding by producing a layer of geotextile which is effectively melt bonded onto the tyre waste is far more effective and durable. In the present invention, the running layer is therefore preferably a layer of hot lay tar macadam of greater than 2cm up to 25cm laid in a single pass. As will be appreciated this is more preferably in the range 5 to 20 centimetres most preferably in the range 10 to 15 centimetres. Typically, further layers will be added subsequently. Stone aggregate is a general term for mixed stone particles which are typically admixed with other materials in construction work. Particulate sizes range from millimetres two centimetres and are commonly known in the industry. The term aggregate is used herein. Whilst the definition of hot lay tar macadam is known in the art if a definition is required then it is a tar macadam or asphalt with an in use laying temperature in the range 275°F (135°C) and 330°F (166°C). In the present invention, a geotextile layer of sheet may be present below the layer comprising the tyre cylinders. In the present invention, a geotextile layer or sheet may be present above the layer comprising the tyre cylinders. In the present invention, a geotextile layer or sheet may be present above and below the layer comprising the tyre cylinders. In the present invention, a geotextile layer or sheet may be present between layers comprising the tyre cylinders. In the present invention, the upper geotextile sheet or layer is preferably formed of a thermoplastic and has a glass transition / melting temperature of less than 170 degrees centigrade. The geotextile of the present invention preferably comprises polyethylene or polypropylene, or mixtures thereof. These materials are both readily available, durable, waterproof, good insulators and become plastic / melt at the required temperature. The preferred material is polypropylene or high-density polyethylene when laying a thick base course, such as 15 centimetres or greater. It is found that under high temperature and pressure a polymer melting point around 160 degrees centigrade is beneficial so is to provide bonding without fluid flow. The preferred material is low density polyethylene when laying a thin base course, a base course of between 5 and 10 centimetres. It is found that under low temperature and pressure then adequate bonding / melting is more readily achieved with low density polyethylene with a melting point around 130 degrees centigrade. When laying, i.e. utilising the method of the present invention in cold weather, cold weather being at a temperature of less than five degrees centigrade then the use of low-density polyethylene is generally preferred. When laying, i.e. utilising the method of the present invention in hot weather, hot weather being as a temperature of greater than around 20 degrees centigrade then the use of high-density polyethylene or polypropylene is generally preferred. The geotextile for use in the present invention, for the upper layer may preferably be a nonwoven. Nonwovens come in many forms but essentially a nonwoven is a form of felt in which fibres are laid randomly to form a mat. The advantage of a nonwoven is that it gives better thermal insulation and therefore less heat is passed through to the underlying tyre waste thus more readily avoiding the problem of gaseous evolution from a tyre waste. The preferred thickness of the geotextile for use in the present invention, in the upper layer is between 3 and 20 millimetres in thickness. More preferably between 4 and 10 millimetres in thickness. This is particularly so in the case of a nonwoven as this can give very effective insulation. The upper geotextile may preferably also comprise particulate carbon. A high surface area particular carbon suitable for the absorption of gases is preferred. The particulate carbon serves to absorb gases which may be evolved, such as from the rubber / plastics component of the tyre cylinders and thus provides increased safety and environmental protection. It should be appreciated that whilst the benefits of the present invention require that the upper geotextile is laid in direct contact with the tyre waste, i.e. the tyre cylinders, it may be possible to have a thin layer of other material present, such as sand however this is not generally desirable as it can be unclear whether any let alone sufficient bonding takes place between geotextile and tyre waste. Some layer of material above the geotextile such as sand, though preferably no thicker than one or two centimetres, particularly if dry sand is used may still be suitable particularly if a thick base layer of tarmac is laid as the melting / bonding of the geotextile can still take place to any protruding upper edges of the tyre cylinders. This layer is most preferably absent. In the present invention the tyre cylinders may be secured to the planar ground surface by means of staples, not shown in the diagrams, which loop over the top of one or more of the tyre cylinders and penetrate through any geotextile layer or layers, through the aggregate, if the aggregate is present at the point of attaching the staples and into the planar ground surface. This improves the efficiency of road construction and the regularity of placement as the tyre cylinders do not move around during placement of the aggregate into the tyre cylinders to form the road base. It is also advantageous in that the staples can act to secure the geotextile layers, particularly the upper geotextile layer 50 so as to stop it being disturbed, such as blown away while awaiting the laying of the running surface for traffic over the previous layers. Drawings The present invention is illustrated by means of the following schematic drawings in which like features are designated with like numerals. It is also be noted that visually identical features, such as feature 32, designated the same feature but are not numbered for clarity. The figures provide: figure 1 illustrates the prior art in the form of a cross section of a road base formed using tyre cylinders; figure 2 shows a cross-section of a road base formed according to the present invention, including optional features; figure 3 shows a perspective view of a staple for use in the present invention; figure 4 shows a plan view of tyre cylinders arranged in the road base of the present invention and a preferred means of fastening the tyre cylinders together in relation to an intended direction of travel on the road base; figure 5 shows a plan view of an alternative arrangement of tyre cylinders and preferred means of passing the tyre cylinders together in relation to an intended direction of travel on the road base; figure 6 shows a plan view of tyre cylinders arranged on the road base of the present invention and more preferred means of fastening selected tyre cylinders together and selected tyre cylinders to the other components of the road base in relation to an edge of the road and in relation to an intended direction of travel on the road base; figure 7 shows a plan view of an alternative arrangement of tyre cylinders arranged on the road base of the present invention and more preferred means of fastening selected tyre cylinders together and selected tyre cylinders to the other components of the road base in relation to an edge of the road and in relation to an intended direction of travel on the road base; The features of the drawings are listed as follows: 10 a generally planar ground surface; 20 optional, lower, geotextile sheet or layer; 30 a tyre cylinder, being the product of vehicle tyres from which the side walls have been removed; similar visual indications represent further instances; 30a a tyre cylinder, being the product of vehicle tyres from which the side walls have been removed, as a plan view juxtaposed for ease of interpretation; 32 tyre cylinder at the edge E of the road base is secured with a staple; 34, tyre cylinder through which a nail exits 36 broken reinforcing steel wire of tyre cylinder 40 infill composition comprising an aggregate; 50 upper, optional, geotextile sheet or layer; 60 running surface for traffic; 70 schematic of a nail fastener as applied using a nail gun; 80 a staple for use in the present invention for the securing of tyre cylinders in the road base; 90 intended direction of traffic on the road base; 100 a cross-section of a road base as known in the art utilising tyre cylinders; 200 a cross-section of a road base of the present invention; 300 a plan view of a tyre cylinder arrangement for use in the road base of the present invention showing a preferred arrangement of nail fasteners, as applied using a nail gun; 320 a plan view of an alternative, close packed, tyre cylinder arrangement for use in the road base of the present invention showing a preferred arrangement of nail fasteners, as applied using a nail gun; 400 a plan view of a tyre cylinder arrangement for use in the road base of the present invention showing a more preferred arrangement of nail fasteners, as applied using a nail gun; 420 a plan view of an alternative, close plants, tyre cylinder arrangement for use in the road base of the present invention showing a more preferred arrangement of nail fasteners, as applied using a nail gun; and E - indicating an edge of the road, away from which the tyre cylinders extend as far 5 as routes required to extend to the further edge, not shown, of the road base. Detailed description Figure 1 illustrates the prior art in the form of a cross-section of a road base formed using tyre cylinders. The road base has a generally planar ground surface 10 such as created by use of ground moving equipment to prepare an existing earth surface. Upon this are placed a plurality of tyre cylinders 30 may close packed arrangement (i.e. most cylinders been contacted by six adjacent cylinders). An infill of aggregate 40 is then placed into the tyre cylinders and optionally contacted to form a main part of the road base and upon this a running surface, such as using further aggregate is then placed. This method and structure presents the aforementioned challenges and disadvantages. figure 2 shows a cross-section of a road base formed according to the present invention, including optional features. Specifically, the road base has the generally planar ground surface 10 as mentioned above, upon which is optionally placed a geotextile sheet to assist in stopping higher layers being washed away or becoming otherwise entrained into the underlying ground. Upon this is placed a plurality of tyre cylinders 30 preferably in an in-line arrangement, but a close packed arrangement may also be used. The tyre cylinders are then, at the radial contact points, secured by means of nails applied by a nail gun to penetrate a nail through both tyre cylinders at or near the point of contact for the purposes of securing them relative want to one another. The direction in which the nail 70 is fired is preferably in the intended direction of travel of traffic (90, see direction of both arrow types) on the road surface 60. This serves to ensure that any movement / vibration will tend to urge the nail 70 further into the join rather than encourage it to be dislodged. Having secured the tyre cylinders aggregate than can then be poured over the layer of tyre cylinders. The layer of tyre cylinders extends across the width of the base of the road and along its length. In the event that the process is repeated to produce an additional layer above the first layer, with any optional intervening geotextile layer 50. In the event of such successive base layers of tyre cylinders and aggregate then only the top layer need necessarily be secured but it is preferred that all those are secured. The tyre cylinders, may be secured by means of an elongate staple 80 this staple enables tyre cylinders, very preferably the tyre cylinders at the edge of the road base to be secured against movement, particularly during the infill phase. The tyre cylinders at the edge of the arrangement of the present invention are most liable to this movement and the use of staples in conjunction, or possibly an alternative to, the nails provides a base with improved integrity for infill of asphalt and subsequent road durability. Upon this base layer or layers a geotextile sheet / layer may be laid, this is particular beneficial when an asphalt layer is placed as the running layer. After any light topping of sand or aggregates, which is very preferably Then, the final running layer of the road may be laid. Figure 3 shows a perspective view of a staple for use in the present invention; the staple 80 comprises an elongate pace of one centimetre diameter Rebar which has been bent back on itself 84 in the middle to provide prongs 82, 82’ the basis of which are cut to provide .86 for ease of insertion. The staples may be inserted before or after placement of the aggregate foot placement before the aggregate is greatly preferred as this secures the tyre cylinders 30, particularly tyre cylinders 30at the edge of the road base critically during the infill phase with the asphalt thus providing a more even and secure road base for subsequent topping with a running surface 60 and / or geotextile layer 50. Figure 4 shows a plan view of tyre cylinders arranged in the road base of the present invention and a preferred means of fastening the tyre cylinders together in relation to an intended direction of travel on the road base. This plan view relates to the sectional view shown in figure 2 and shows the preferred direction of insertion of the nails as applied with a nail gun. Nails attaching tyre cylinders 32 at the edge E of the road base are preferably fired inwards to secure outermost ties to inner tyres. As mentioned previously feature 90 indicates the preferred or intended direction of travel of the vehicular traffic. Figure 5, shows a plan view substantially equivalent to that shown in figure 4 were in the tyre cylinders are arranged in a close packed array. It will be understood, as with all the other figures that the arrangement of the tyre cylinders shown is merely an example selection for which the overall road base will utilise multiple repeats in an array (regular or irregular). In this particular example of the present invention the preferred direction of the nails is in the intended direction of traffic flow. For completeness at this point it is noted that on a single carriageway road then this implies that one side of the road will have the nails preferably fired in a first direction and the other side of the road will have the nails preferably filed in the other direction. Figure 5 shows a plan view of tyre cylinders arranged on the road base of the present invention and more preferred means of fastening selected tyre cylinders together and selected tyre cylinders to the other components of the road base in relation to an edge of the road and in relation to an intended direction of travel on the road base. Figure 6 shows a plan view of an alternative arrangement of tyre cylinders arranged on the road base of the present invention and more preferred means of fastening selected tyre cylinders together and selected tyre cylinders to the other components of the road base in relation to an edge of the road and in relation to an intended direction of travel on the road base. Figure 7 shows an important aspect of the use of males fired by a nail gun through the tyre cylinders as used in the present invention. Whilst the skilled person may contemplate a number of different fasteners, these nearly all require drilling of an aperture to receive the fastener. Drilling therefore provides an aperture having an edge. However, the method of the present invention fires nails through the material so no material of the tyre cylinder 30 is actually removed it is simply displaced this means that the impacted nail becomes very firmly gripped by the material of the tyre cylinder. Very significantly, and differing from conventional uses of males, including males inserted by nail guns the substrate of the present invention, the tyre cylinders, as is known in the art comprises layers of wires and fabric embedded within a rubber composite. Therefore, when filing a nail gun through the tyre, or in the present case the tyre cylinder, the nail serves to break the wires and forces them to protrude in the direction in which the nail is fired. As will be appreciated this requires considerable force and is a further reason why the use of a nail gun in the present invention differentiates over any other conventional use of a nail. As can be observed from the figure the nail 70 penetrates the tyre cylinders 30, 34 and gives rise to portions of broken wire 36 which actively impinge upon the nail so as to actively prevent its removal without the need for any additional securing means.

Claims

1. A method of forming the base of a roadway, the method comprising the steps: a. providing a generally planar ground surface;b. placing over said surface an optional, lower, geotextile sheet or layer;c. placing upon said lower geotextile a plurality of tyre cylinders, being the product of vehicle tyres from which the side walls have been removed;d. wherein the tyre cylinders are laid radially on said ground or geotextile surface in a regular pattern;e. infilling said tyre cylinders and surround with a composition comprising an aggregate; optionally compacting said aggregate;f. optionally repeating steps c, d and e;g. placing over said surface an optional further, upper, geotextile sheet or layer;h. laying a running surface for traffic over said previous layers; wherein:upon placing said plurality of tyre cylinders in step c said tyres are joined together by means of nails applied using a nail gun.

2. The method of claim 1 wherein the nails applied using a nail gun using sufficient energy and length of nail to penetrate the tyre walls of two tyre cylinders where they abut is placed in step c.

3. The method of claim 1 or claim 2 wherein the nails of the present invention applied by being impacted upon the tyre cylinders at a velocity of at least 50 metres per second.

4. The method of any preceding claim wherein the nails are applied in the direction of the intended flow of traffic on the roadway.

5. The method of any preceding claim wherein the tyre cylinders on the sides of the base of the roadway are connected by said nails.

6. The method of any preceding claim wherein one or more tyre cylinders are secured by means of a staple placed over the edge and down the inner and outer sides of a cylinder, and penetrating the planar ground surface.

7. The method of claim 6 when the staples are applied to the tyre cylinders on the sides base of the roadway.

8. The method of any preceding claim wherein the road base is a road base for a high-speed roads.

9. The method of any preceding claim wherein the running surface comprises tar macadam.

10. The method of any preceding claim wherein the running surface comprises concrete.11 .The method of any preceding claim wherein a lower geotextile sheet is present.

12. The method of any preceding claim wherein the upper geotextile sheet is present.

13. The method of any preceding claim wherein one layer c, d, e is present.

14. The method of any preceding claim wherein two layers c, d, e are present.

15. The method of claim 13 wherein a geotextile sheet is present between said two layers.

16. The method of any of claims 11 to 15 wherein said geotextile sheet or layer is formed of a thermoplastic and has a glass transition temperature of less than 160 degrees centigrade.

17. The method of any of claims 10 to 15 wherein said geotextile sheet comprises polyethylene or polypropylene.

18. The method of any preceding claim wherein the running surface for traffic laid over the previous layers is a hot melt tarmac.19.The base of a roadway formed by the method of any preceding claim.

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