Improved arrangement of re-purposed tyres for creating a roadway

Abstract

A method of forming a base of a roadway comprises the step of: providing a planar ground surface 10; placing radially in a regular pattern a plurality of tyre cylinders from which the side walls have been removed; infilling the tyre cylinders with an aggregate; and, laying a running surface over the previous layers. The upper edges of the tyre cylinders define nodes and are arranged in a non-linear pattern. The non-linear pattern reduces resonant effects which may give rise to vibrational forces. The nodes may be arranged randomly, pseudo-randomly or stochastically. The laying of the tyre cylinders may be wholly or partially automated. Smaller diameter tyres 32 may be placed inside larger tyres 30. The pattern of the nodes may repeat with a multimodal or bimodal pattern. Lower and upper geotextile sheets may be provided below and above the tyre cylinders and may be formed from a thermoplastic. The running surface may be hot melt tarmac or concrete. The roadway may be high-speed.

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. A number of problems can arise from the straightforward laying of tyres to form 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 5 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 10 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: the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a non-linear pattern. As disclosed in the background section, the use of tyre cylinders for the production of a roadway base is known, however such use is generally been for utility roads and, were more widely used, for example in the United States, finished with a concrete surface. It being no accident that the predominant product in the US is produced under the mechanical concrete (RTM) brand. 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. 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, effects such as this, even when one or two orders of magnitude smaller, present in the normal road surface can give rise to significant driver fatigue in general and wear of vehicle and road surface. This context is given since it is been found with established uses of tyre cylinders for constructing roads that since the tyre cylinders produce a repeat pattern of between 14 and 19 inches (35 and 48cm) and the tyres which are running over them also have a diameter (self-evidently) of exactly the same size then there is a very high possibility of resonance effects occurring and furthermore of beat frequencies occurring, i.e. were two harmonics of similar frequency interfere to give a stronger lower frequency. Whilst this effect may be evident when explained, it has only come to light in testing and is not part of the common general knowledge. In the present invention, there is the requirement that the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a non-linear pattern. This disrupts and obviates such resonant effects and serves to avoid the disadvantages. The present invention includes the provision of a high-speed roadway constructed by the method of the present invention and including the method of the present invention. This is because the benefits of the present invention are most evident on high-speed sections of roadway. For example, at 100 km / h the velocity is approximately 27 ms-1 and the nodes of tyre cylinders (see later figures) can therefore represent a vibration in the order of 50 Hz and beat frequencies at lower frequencies such as one or 2 Hz. This frequency is sufficient to be distracting as is evident from lighting which malfunctions at the mains frequency. To explain these features the drawings will now be referred to, the further details of which can be found below in the specific description. Figure 1 shows a cross-section of a road constructed with a road base comprising tyre cylinders as known in the art (see background above). Figure 2 shows in plan view the aggregate portion (steps / layers c,d,e) of the base layer with a known arrangement of tyre cylinders which may be used. Lines A-A and B-B represent notional tracks along which a vehicle tyre will roll over the road surface. As shown in figure 3 the high points (they need not necessarily be high merely different) defined by the edges of the tyre cylinders, herein referred to as the nodes are shown. As can be seen these nodes define a pattern, see road surface 60 in 210 A-A and 210 B-B where these nodes form a linear pattern. This is the ideal condition given the close similarity (on average identical) between the spacing of the nodes and the diameter of a vehicle tyre (the spacing of course being related by the relationship (it diameter) for harmonic vibrations to arise. Therefore, even small but regular disturbances in the running surface of the road can give noticeable effects. Another arrangement of tyre cylinders is shown in figure 7 with corresponding pathways A and F giving rise to corresponding linear patterns of the nodes. This further arrangement can be termed a close packed array but is not preferred since it uses a relatively higher number of tyre cylinders per unit area and whilst tyre cylinders represent a low-cost use of recycled material the transport, handling and placement carries a time and cost which can be limited by the preferred two-dimensional linear pattern as shown in figure 2. One solution to this problem within the scope of the present invention is the random laying of the tyre cylinders and this effectively addresses this problem as any repeat pattern is removed. In the present invention, the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a random or pseudorandom pattern. The present invention preferably includes where the tyre cylinders are arrayed in a random or pseudorandom pattern. A pseudorandom pattern is preferred as this is amenable to automation. Most preferred is a repeating pseudorandom pattern as this can be more readily reproduced although still effectively requires a robot arm, or similar automation, to carry out the placement. The pseudorandom pattern of the nodes in the present invention, may be a stochastic pattern. This latter point is significant since, in practice, the manual random or pseudorandom laying of tyre cylinders In the present invention, has is been found impractical in extended operation. The laying of a road base is an industrial process and requires regularity and automation and any irregularity gives rise to weak points, and interruption in workflow. Manual operators sooner or later become disorientated or lapse into the creation of regular patterns. A preferred solution is therefore where the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a repeating pattern with a non-linear repeat pattern. The repeat pattern preferably includes a repeat pattern element which is 1 / 5 or less of the diameter of the tyres, more preferably 1 / 7 or less of the diameter of the tyres. For the purposes of the present invention a linear repeating pattern is of the form A-A-A-A. A pattern of the form A-B-A-B is defined as being non-linear. In this instance B represent such a repeat pattern element. This arrangement may be considered to represent wherein the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a repeating pattern with a multimodal repeat pattern. That is a plurality of frequencies will be produced when moving across the nodes linearly (as illustrated in the attached figures (e.g. 410 C-C, 410 D-D). Mathematically this feature of the present invention may be defined as follows: n——x? Wherein H is the Heaviside step function. Or using sign function, (with finite range of -999 and 999 being arbitrary values). wherein a non-linear function is defined where a # c / 2 with an error of 10%, preferably 5% more preferably 2%. All values being in meters. B represents the width of the node such as in 210-A-A is narrow in width and in 2 10B-B is larger in width but is otherwise not a determinant of a linear on non-linear pattern. All values being in meters. Graphically this feature of the present invention (i.e. a schematic graphing of the function) is shown in 60’, 60”, 60’” and 60 of 210-A-A, 210-B-B ,410 D-D and 410 C-C respectively. It is understood that the present invention is also applicable to what might be considered diagonal patterns of tyre cylinders but in practical use in road construction tyre cylinders are preferably placed in what are effectively rows, whether or not close packed. 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 the 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 joined by means of nails filed by email gone through the walls of the tyre cylinders where they abut so as to join the tyre cylinders. This is a highly effective means for joining the tyre cylinders and does not require the drilling of any holes and the metal reinforcement of the tyre cylinders, as an inherent feature of the construction of a radial tyre tread which is the predominant form of tyre used acts to retain the nails in place. 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 shows a vertical cross section through a base of the roadway constructing using tyre cylinders as known in the art; and figure 2 shows a plan view of an arrangement of tyre cylinders as known in the prior art; figure 3 shows cross sections through figure 2 along lines A-A and B-B and below said cross sections an illustration of the nodes as defined by the present invention; figure 4 shows a repeating pattern of tyre cylinders suitable for carrying out the present invention by the provision of a non-linear array of nodes; figure 5 shows a repeating pattern of tyre cylinders suitable for carrying out the present invention by the provision of a non-linear array of nodes arising from a close packed array of tyre cylinders; figure 6 shows cross sections through figure 4 along the lines C-C and D-D said cross sections illustrating the nodes in arrangement falling within the scope of the present invention. Figure 7 shows a close packed array of tyres such as is known from the prior art showing that the issue of a linear array as shown in figure 2 is also present in this arrangement, even if in a less exaggerated manner. Figure 8 shows a plan view of randomly positioned of tyre cylinders, to schematically illustrate the concept. 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, a plan view juxtaposed for ease of interpretation; 32 a relatively smaller diameter tyre cylinder, being the product of vehicle tyres from which the side walls have been removed; similar visual indications represent further instances; 40 infill composition comprising an aggregate; 50 upper, geotextile sheet or layer; 60 running surface for traffic; 100 Road base as known in the art utilising tyre cylinders; 200 an arrangement of tyre cylinders as known in the art for use in constructing a road base; 210 A-A an illustration of the nodes as defined in the present invention, for an arrangement of tyres; 210 B-B an illustration of the nodes as defined in the present invention, for an arrangement of tyres; 300 a road base of the present invention using tyre cylinders presenting a non-linear array of nodes; 410 C-C an illustration of the nodes as defined in the present invention, for an arrangement of tyres; 410 D-D an illustration of the nodes as defined in the present invention, for an arrangement of tyres; 500 a plan view of an arrangement of tyre cylinders presenting a non-linear array of nodes of the present invention; 700 an arrangement of tyre cylinders as known in the art for use in constructing a 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 plan view of an arrangement of tyre cylinders as known in the prior art; the purpose of this figure is to illustrate that the line of travel of a vehicle tyre on a road base constructed in the manner of the prior art is illustrated by two exemplary lines A-A and B-B. Given that the bases of the roadway are constructed of tyre cylinders 32 on the ground base 10 and the tyres of the vehicles travelling over will generally be of the same diameter is used to illustrate the issues found with the prior art constructions. Those lines are considered further in figure 3 wherein in 210 a-a the under surface of the road traversed by a typical vehicle running over that surface is illustrated and together with it, underneath a stylised graph of the change in the road surface (ready exaggerated for effect) is presented. This is also shown for another trajectory to 10 B-B where the same effect is shown although inverted. It is noted that the present invention is not based upon this evidence for this evidence is merely presented to illustrate the understanding of why the vibration effects on prior art roads of the relevant construction are found and as to why the solution of the present invention is effective. However, the applicant is not bound by theory and this is merely for illustration. Figure 4 shows the road base construction of the present invention comprising the generally planar ground surface upon which is optionally but preferably laid a geotextile layer 20 upon which an arrangement of tyre cylinders comprising larger 30 and smaller 32 diameter cylinders is placed such that the smaller cylinders 32 reside within the larger cylinders 30. This is then infilled with aggregates 40 to provide a lower road base and upon this is placed an optional, but preferred geotextile layer 50 before finishing with road surface 60 which is preferably tar macadam and more preferably a hot lay tar macadam. This provides a road surface 300 with a repeat pattern which does not give rise to vibration on high-speed roads. Figure 5 shows a repeating pattern of tyre cylinders suitable for carrying out the present invention by the provision of a non-linear array of nodes. This shows two trajectories for a vehicle tyre C-C and D-D illustrating that the simple linear repeat of the prior art is disrupted such that whilst a repeating pattern is present to the repeated pattern is not of the simple linear type giving rise to the vibration issues with the prior art, particular found on high-speed roads. The reader is requested to consider that the definition of a linear pattern is an internal definition of the present invention and should be construed accordingly, i.e. not necessarily as a mathematical definition. Figure 6 shows a repeating pattern of tyre cylinders suitable for carrying out the present invention by the provision of a non-linear array of nodes arising from a close packed array of tyre cylinders, this figure illustrates the disrupted pattern on the road surface 60 and 60 with tracks for 10 C-C and for 10 D-D corresponding to the equivalent analysis explained regarding the prior art as above. This is further illustrated in Figure 6 shows cross sections through figure 4 along the lines C-C and D-D said cross sections illustrating the nodes in arrangement falling within the scope of the present invention. Here it is clear that online 60 the simple repeat, linear pattern in the prior art is avoided and with it the vibration effects. Figure 7 shows a close packed array of tyres such as is known from the prior art showing that the issue of a linear array as shown in figure 2 is also present in this arrangement, even if in a less exaggerated manner. In this example trajectory F-F has less of a vibration effect but trajectory A’-A’ remains as in the prior art and it is simply impractical for vehicles to choose a track along the road based upon vibration effects rather than track road safety. It is also noted that the close packed array uses a greater number of tyres to construct the road and this as unnecessary and undesirable overhead in terms of the labour in constructing a road when such a close packed array is not necessary for effective road construction of the present invention. Figure 8 is now referred to as this shows the theoretical best manner to avoid the vibration effects found on high-speed roads of the prior art construction using tyre cylinders. However, whilst this solution is within the scope of the present invention it is not generally preferred (over other patterns of linear repeat disruption) since it can 5 lead to irregular voids as is evident from simple visual inspection of the gaps between tyre cylinders 30 in the arrangement 500 of this figure.

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:the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a non-linear pattern.

2. The method of claim 1 wherein the method of forming the base of a roadway the construction of a high-speed roadway.

3. The method of claim 1 or claim 2 wherein the nodes are randomly or pseudo-randomly arranged in said non-linear pattern.

4. The method of claim 3 when the nodes are arranged stochastically.

5. The method of any preceding claim wherein step c is wholly or partially automated.

6. The method of claim 1 or claim 2 wherein where the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a repeating pattern with a non-linear repeat pattern.

7. The method of claims 1,2 or 6 wherein where the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a repeating pattern with a multimodal repeat pattern.

8. The method of claim 7 wherein where the upper edges of the plurality of tyre cylinders define nodes and wherein those nodes are arranged in a repeating pattern with a bimodal repeat pattern.

9. The method of claim 8 wherein the bimodal repeat pattern is defined by the equation:.x — (c + b] + anwherein a non-linear function is defined where a # c / 2 with an error of 10%, preferably 5% more preferably 2% and B represents the width of the node, all values being in meters.

10. The method of any preceding claim wherein a lower geotextile sheet is present.11 .The method of any preceding claim wherein the upper geotextile sheet is present.

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

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

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

15. The method of any of claims 10 to 14 wherein said geotextile sheet or layer is formed of a thermoplastic and has a glass transition temperature of less than 160 degrees centigrade.

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

17. The method of any preceding claim wherein the running surface for traffic laid over the previous layers is a hot melt tarmac.

18. The method of any of claims 1 to 16 wherein the running surface for traffic laid over the previous layers is concrete laid in situ.19.The base of a roadway formed by the method of any preceding claim.

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