EP1579074B1 - Low-grip track for vehicles - Google Patents

Description

The present invention relates to a track for driving land vehicles with motor in low adhesion conditions, with a pavement comprising a coating of asphalt concrete. The present invention also relates to a mix for the realization of such a track, and a method for making such a track.

The vehicles concerned by the present invention are four-wheeled passenger cars as well as competition vehicles, the latter including both modified road vehicles according to various sport categories and specific vehicles such as single-seaters, including passenger cars. karts. The invention also relates to two-wheeled vehicles such as motorcycles and motorcycles, road or competition.

• la désignation du type d'enrobé
• la granulométrie
• les proportions de sable, de gravillons et/ou de pierres concassés et/ou roulés
• le type de liant
• le dosage du liant
• la nature et quantité des éventuels additifs
• les teneurs en vides
• les valeurs indicatives de stabilité et de fluage.

Although roads and paths in dirt, laterite or still covered with layers of loose gravel or concrete slabs are still frequently encountered, especially in the less industrialized countries, pavements with asphalt concrete pavements tend to to generalize. In industrialized countries, they have become the rule. In general, a bituminous concrete coating comprises one or more support layers, located above the foundation layer of another suitable support. The (where) layer (s) of support provide the bearing capacity of the coating. Above the one or more support layers is arranged a wearing course, which is the upper layer of the coating. It ensures road safety and comfort of traffic. Both the support layers and the wearing course are made using mixes composed of mineral aggregates and bituminous binders and any additives. Asphalt specifications include

• the designation of the type of asphalt
• particle size
• the proportions of sand, chippings and / or crushed and / or rolled stones
• the type of binder
• binder dosage
• the nature and quantity of any additives
• the contents in voids
• indicative values of stability and creep.

For the construction of public roads, these specifications comply with many national standards. For example, in Switzerland, the design of asphalt concrete pavements complies with the SN640 431b standard, the requirements for mineral aggregates generally comply with the SN670 130 standard and with several more specific standards, concerning, for example, fillers or methods of measurement. Bitumens can comply with SN671 110. Residual void and filled void contents, stability, rigidity and creep, commonly referred to as Marshall characteristics, are measured on the basis of SN671 969c and SN671 967a.

An extremely important feature of a wearing course of a public roadway is its anti-slip quality. The slipperiness of a pavement surface is variable over time, depending on wear and environmental conditions. It is usefully measured and quantified in particular by means of a standardized oscillating pendulum called "skid resistance tester", and expressed in units called SRT. The measurement method is the subject of SN640 510b and SN640 511b in Switzerland.

Improving the anti-slip quality of the wearing course, ie increasing the adhesion of the tires to the surface of the coating, is a constant concern of the skilled person. It seeks to obtain SRT values greater than 70 and preferably greater than 75. Numerous proposals have been made to this effect. For example, the document WO 99/19566 proposes to make the upper surface of the wearing course rougher in enriching it in crushed, sharp-edged aggregates so as to increase the frictional forces. Numerous other documents describe the realization of draining mixes: these are characterized by the presence of a significant percentage of voids, of the order of 20%, corresponding to at least about 12% of non-filled voids communicating, performing drainage of the wearing course. An example of such a coating can be cited that described in the document FR 2 674548 .

Difficulties in controlling vehicles traveling on roads with asphalt concrete pavements, which is the case for most motor vehicles, are considerably increased when the roadway is wet, snow-covered, or covered with dead leaves and gravel. or mud, or even oil residues or thin sand films, all of these circumstances having a common denominator, namely that the vehicle's grip capacity on the roadway is greatly diminished. We know that compared to optimal conditions, vehicle in perfect condition on pavement of good quality and dry, the adhesion can be reduced by half on a wet pavement, of two thirds if the tires are worn, and even until the tenth in conditions of icy road or in the presence of puddles generating a phenomenon of aquaplaning.

Some driving education organizations organize specific courses in winter conditions. Because these courses are weather dependent, they can usually only be provided for a few days each year when the pavement is covered with snow or ice.

To teach drivers to control their vehicles in these difficult conditions, it has already been proposed to develop runway segments or annular tracks with a synthetic sliding coating, made by resins, varnishes or paints. adhesion vehicles on these runway segments or on these rings are greatly diminished by watering them constantly with water.

These facilities teach the basics of driving in low grip conditions, but have several flaws.

The resins and paints used are expensive and, during braking and skidding, are gradually blackened and even torn off, so that they must be replaced frequently. In a regularly functioning teaching center, these synthetic coating films must be replaced at least twice a year. For this reason, and because it is necessary to constantly water the track, the length of it is necessarily limited to lengths less than or about one hundred meters. It is not practically feasible to make sections of the road or automobile circuit type of a length of several kilometers. The variety of practicable exercises on these very short tracks is therefore necessarily very limited.

In addition, these tracks plasticized or coated with paint or resin require the use of smooth tires. For practical reasons, these tracks are always used with the same school vehicles; the student driver can not practice with his vehicle that he uses elsewhere.

Some sports organizations, such as the IRSI (Ice Race International Series), organize snow-covered and / or ice-covered races. These races are of increasing interest to the public, because of their spectacular nature, but can be organized, because of weather hazards, only in mountain areas and during the winter period when snow and / or the low temperatures necessary for the maintenance of a snow and ice track are ensured.

The use of resins or paints can not in practice be considered to cover an automobile racing circuit to simulate a race on ice because of the extremely high powers developed by racing vehicles, which would cause the almost immediate tearing of the film of paint or resin.

The document DE 296 15 276 U discloses a mix for producing a wearing course showing the features of the preamble of claim 1.

A first object of the present invention is to provide a track for driving motor vehicles reproducing conditions of low adhesion, and with a layout of the long and varied road course.

A second object of the present invention is to provide such a track with an installation cost which does not substantially exceed that of a road section having the same arrangement.

A third object of the invention is to provide such a track whose maintenance cost is low, in particular which does not need frequent replacement of a surface coating.

A fourth object of the invention is to provide a track whose structure withstands without unacceptable deformations violent mechanical stresses such as those caused by very powerful competition vehicles.

These goals are achieved by means of a track of the defined type of entry, where said bituminous coating comprises a wearing course consisting of a non-draining asphalt whose slip, measured on the "skid resistance tester" is between 55 and 68 SRT units.

The SRT value of a wearing course can be lowered, in particular by pausing at high ambient temperature, by increasing the proportion of the binder, by increasing the proportion of the filler and / or by decreasing the thickness of the layer. layer. It has been found by the inventors that a range of 60-67 SRT units is optimal for application to a competition circuit.

The surface of the track according to the invention has in the dry state the same conditions of adhesion as a normal wet road. The choice of a non-draining asphalt mix, in particular a mix with a residual voids content of 4 ± 2%, a filled voids content of 85 ± 6%, gives it the properties of a regular road which has undergone a very strong rain, after simply having a light rain or being subjected to light watering.

It allows the teaching of driving on wet roads in pleasant climatic conditions. It makes it possible to provide such education in areas where for several months in the year, or even during the whole year, it hardly rains, and where the water is a commodity too valuable to be spread regularly on a roadway .

In addition, if the track according to the invention is heavily wetted by a heavy rain or a sprinkler system, its grip characteristics are very similar to those of an icy pavement. The track according to the invention thus makes it possible to teach throughout the year the extremely specific driving technique adapted to such conditions, which naturally occur only a few days per year.

• la réalisation de la piste met en oeuvre exclusivement la technologie de la construction routière, aussi bien au niveau des équipements, c'est à dire centrale d'enrobage, véhicules de transport, machines de pose et rouleaux de compactage des couches de support et de roulement.
• Les procédures de mise en place sont exactement les mêmes que pour une voie publique. Par conséquent, la mise en place peut être exécutée par une entreprise de travaux publics sans que le personnel ait besoin d'une formation spécifique.
• la piste selon l'invention peut présenter la configuration d'un tronçon de route ordinaire de plusieurs kilomètres de longueur avec toutes les variantes topographiques que l'on peut rencontrer sur une route, telle que virages en épingle à cheveux, grandes courbes, relevées, en dévers, portions de parcours en pente plus ou moins forte, etc.

The track according to the invention has many advantages over the low adhesion driving training tracks known in the state of the art, ie tracks covered with a layer of resin or paint.

• the realization of the track implements exclusively the technology of road construction, as well at the equipment level, ie coating plant, transport vehicles, laying machines and compacting rollers of the support and rolling layers.
• The installation procedures are exactly the same as for a public road. Therefore, the installation can be carried out by a public works company without the staff needing specific training.
• the track according to the invention may have the configuration of an ordinary road section of several kilometers in length with all the topographic variants that can be encountered on a road, such as hairpin bends, large curves, raised, in cant, portions of course more or less steep, etc.

Preferably, the track according to the invention can be made in the form of a closed circuit, in a pattern identical or similar to a racing circuit, with the usual security equipment of this type of installation such as clearance zones. , sandboxes, slides, tire stacks, camera tracking systems and safety lights.

Preferably, the non-draining asphalt of the wearing course has a Marshall stability of greater than 10 kN and a Marshall creep of less than 3.5 mm, measured according to SN 671 967a and SN 671 969b.

The wearing course then has sufficient stability and resistance to deformation so that the track can accommodate endurance racing vehicles or single-seaters without exhibiting deterioration phenomena such as erosion, pulling, etc., greater than that of a classic racetrack track.

Such a track therefore allows the organization of competitions in which the vehicles necessarily perform spectacular slippages popular with the public and already at speeds much lower than those reached on a conventionally structured track having the same configuration.

According to the invention, the wearing course is carried out using a non-draining mix whose mineral aggregates consist of more than 90% of 0/4 granular class materials and in which the binder / coated content is 8.5 ± 1% by weight, and the inorganic aggregates used comprise a high proportion of rolled sands, for example from 30 to 50%, and have a pass greater than 95% to the 2.8 mm analysis sieve.

In particular, the inorganic aggregates may be chosen so as to have particle size values within the following limits: Analysis sieve mm Passing (% mass) 4 98-100 2.8 95-100 2 85-95 1 60-70 0.5 40-50 0.25 25-35 0,125 15-25 0.09 10-20

The bituminous binder may be chosen from the binders known in the state of the art for producing layers rolling. It may in particular be chosen from bitumens satisfying the SN 671 110 standard. It may also be chosen from bitumens modified with polymers satisfying the SN 671 400 standard. In the case of a track intended to accommodate automobile competitions, a bituminous binder of the type used to produce road surface layers of AB-S or AB-H type is preferably chosen. To make tracks in dry and hot climates, B55 / 70 or B50 / 70S bitumens are preferably used.

• la figure 1 représente la courbe granulométrique d'un premier exemple de réalisation;
• la figure 2 représente la courbe granulométrique d'un deuxième exemple de réalisation
• la figure 3 représente la courbe granulométrique d'un troisième exemple de réalisation

The invention will be better understood by those skilled in the art by examining the characteristics of three embodiments of a mix according to the invention and the accompanying figures, in which

• the figure 1 represents the granulometric curve of a first embodiment;
• the figure 2 represents the granulometric curve of a second exemplary embodiment
• the figure 3 represents the grain size curve of a third embodiment

Example 1

Mineral aggregates employed included 97.3% sand passing the 2.8mm test sieve. The percentage of sand crushed in the sand fraction was 60%. Mineral aggregates also contained 2.7% grade 4/11 gravel. Table 1 gives the particle size according to SN 670 810c. Table 1: Sieve Passing (% mass) 0.09 12.5 0,125 16.0 0.25 26.3 0.5 44.8 1.0 65.8 2.0 88.4 2.8 97.3 4.0 98.6 5.6 99.2 8.0 99.7 11.2 100.0 16.0 22.4

• pour le tamis de 0,5 où le passant est supérieur à 44%
• pour le tamis de 1 où le passant est supérieur à 65%
• pour le tamis de 2 où le passant est supérieur à 85%

Those skilled in the art will recognize that the particle size values of Table 1 are surprising compared to the values usually accepted for the production of road surface wearing courses. By way of comparison, these particle size values have been represented in the form of the curve (1) on the Fig. 1 , in relation to the limits of the nominal grain size values allowed according to SN 640 431b for a wearing course of the AB3L type, shown in dashed lines. It is found that, even if the particle size curve of the mix according to the invention intersects the lower nominal limit, for sieves 0.09 to 0.25, this granulometric curve is essentially out of the norm, in particular

• for the sieve of 0.5 where the passer is greater than 44%
• for the sieve of 1 where the passer is greater than 65%
• for sieve of 2 where the passer is greater than 85%

An inflection of the particle size curve due to the presence of a small quantity of chippings of the 2.8 / 11.2 fraction can be observed.

The binder used was a PETROPLUS B50 / 70S bitumen (Cressier Refinery). It is a doped bitumen containing an additive preventing the stripping on slightly damp grains. The amount of binder used, of the order of 8.8% relative to the mass of aggregates, was much larger than the amounts usually used for road AB layers.

• Finisher à chenilles avec table vibrante hydraulique extensible à 5 mètres, marque ABG et de type TITAN. La table est réchauffée à gaz à une température de 130°.
• 1 compacteur à billes, poids 16 tonnes
• 1 compacteur mixte bille et pneus, poids 12 tonnes

The implementation equipment includes.

• Crawler Finisher with hydraulic vibratory table extensible to 5 meters, brand ABG and type TITAN. The table is heated to gas at a temperature of 130 °.
• 1 roller compactor, weight 16 tons
• 1 roller and tire compactor, weight 12 tons

The temperature of implementation of the asphalt was 168 °.

After analysis, the mix has the following general characteristics: Binder content / Coated (% by mass): 8.07 Density (t / m ³ ): 2,375 Filler / Bitumen ratio: 1.4 Wealth module: 4.81

The Marshall features are as follows: Residual void content (% vol.): 4.9 Content in filled voids (% vol.): 7.4 Apparent density (t / m ³ ): 2,260 Stability (kN): 11.8 Creep (mm): 3.1 Rigidity (kN / mm): 3.8

Those skilled in the art will find that, surprisingly, despite the high binder content, the mix is not fluent and has excellent stability and rigidity values: in this aspect, the wearing course would have the following characteristics: a road layer of the AB-N or AB-S type, whereas on the contrary, with regard to the anti-slip qualities, the wearing course would be perfectly unsuitable for normal road use, since the SRT values show that the track according to the invention, when dry, has SRT values similar to those of a wet normal road surface and that the track according to the invention, wet, presents adhesion values close to that of a road covered with ice.

Example 2

Mineral aggregates used included 97.9% sand passing the 2.8mm test sieve. The percentage of sand crushed in the sand fraction was 60%. Mineral aggregates also contained 2.7% grade 4/11 gravel. Table 2 gives the particle size according to SN 670 810c. Table 2: Sieve Passing (% mass) 0.09 11.5 0,125 14.8 0.25 24.3 0.5 41.3 1.0 63.4 2.0 89.0 2.8 97.9 4.0 98.8 5.6 99.2 8.0 99.5 11.2 99.5 16.0 22.4

• pour le tamis de 1 où le passant est ~ 65%
• pour le tamis de 2 où le passant est ~ 90%.

Those skilled in the art will recognize that the particle size values in Table 2 are also surprising compared with the values usually accepted for the production of road surface wearing courses. As comparative, these particle size values have been represented as a curve (2) on the Fig. 2 , in relation to the limits of nominal grain size values allowed according to SN 640 431b for a wearing course of the AB3L type. It is found that, even if the particle size curve of the mix according to the invention intersects the lower nominal limit at the level of the sieve 0.5, this granulometric curve is essentially out of the norm, in particular

• for the sieve of 1 where the passer is ~ 65%
• for the sieve of 2 where the passer is ~ 90%.

We will also note the inflection of the granulometric curve due to the presence of a small gravel fraction 2,8 / 11,2.

The binder used was the B50 / 70S bitumen of Example 1. The amount of binder used, of the order of 8.4% relative to the mass of aggregates, was significantly greater than the amounts usually used. works for road AB layers. The temperature of implementation of the asphalt was 170 degrees.

The processing equipment is the same as that of example 1.

After analysis, the mix has the following general characteristics: Binder content / Coated (% by mass): 7.76 Density (t / m ³ ): 2,386 Filler / Bitumen ratio: 1.4 Wealth module: 4.68

The Marshall features are as follows: Residual void content (% vol.): 6.0 Content in filled voids (% vol.): 77.3 Apparent density (t / m ³ ): 2,256 Stability (kN): 10.8 Creep (mm): 2.7 Rigidity (kN / mm): 4.1

Those skilled in the art will also note for this example that, surprisingly, despite the high binder content, the mix is not fluent and has excellent stability and rigidity values, whereas on the contrary, As regards anti-slip qualities, the wearing course would be perfectly unsuitable for normal road use.

Example 3

The mineral aggregates used included 99.4% sand passing the 2.8mm test sieve and practically did not include gravel with a particle size greater than 4. The percentage of sand crushed in the sand fraction was 60%. Table 3: Sieve Passing (% mass) 0.09 14.6 0,125 18.0 0.25 27.6 0.5 42.3 1.0 61.2 2.0 88 2.8 99.4 4.0 99.9 5.6 100

The particle size values in Table 3 have been represented as a curve (3) on the figure 3 . Those skilled in the art will recognize that these values coincide in substance with the lower nominal particle size limit allowed according to SN 640 431b for a wearing course of type AB3L.

The binder used was also the bitumen B50 / 70S of Example 1. The amount of binder used was 9.16% relative to the mass of aggregates.

The temperature of implementation of the mix was 171 ° C; the equipment and the conditions of implementation were for the remainder identical to those of examples 1 and 2

After analysis, the mix has the following general characteristics: Binder content / Coated (% by mass): 8.39 Density (t / m ³ ): 2,365 Filler / Bitumen ratio: 1.6 Wealth module: 4.90

The Marshall features are as follows: Number (s) of reheating: 1 Compaction temperature: 153 Residual void content (% vol.): 2.5 Content in filled voids (% vol.): 88.3 Apparent density (t / m ³ ): 2,306 Stability (kN): 7.9 Creep (mm): 4.4 Rigidity (kN / mm): 1.8

Those skilled in the art will find that this example of asphalt having a very high binder content has values of stability, rigidity and creep lower than the two previous examples.

• mesure SRT selon norme SN 640 510b: 66 unités SRT
• mesure au "skid résistance tester" du revêtement à sec: 75 unités SRT

This coating has the following slip values:

• SRT measurement according to SN 640 510b standard: 66 SRT units
• measurement at the "skid resistance tester" of the dry coating: 75 SRT units

Although the second measurement is performed under non-standard conditions, it shows that this coating has the same slip characteristics as a wet ordinary road surface.

Example 4: Driving tests with a kart

The asphalt used for producing the wearing course is that of Example 3. The test track made is a rectangular segment 35 m long and 12 m wide. The wearing course of 20mm thickness on average is implemented by means of a lacquer-bitumen bonding layer on a pre-existing HMT 25 support layer. An equivalent surface consisting of the support layer, located next to the test track serves as a comparison track. A ^3rd surface located upstream of the two preceding uses momentum area to start the test vehicle. The tests were conducted by a professional racing driver with a 100cm ^{3 single} speed competition kart.

at. Braking tests

The test track and the comparison track are both slightly wet with a small rainfall. The pilot launches the kart, first at low speed, of the order of 40km / h, then at a higher speed, of the order of 60km / h, on the momentum area successively facing the runway. test and at the track of comparison and, after having traveled a distance of approximately two meters on these tracks, materialized by studs on each of the two tracks, brakes to the maximum until the stop.

• piste d'essai: 15m
• piste de comparaison: 10-11m

Braking distance at low speed (40Km / h):

• test track: 15m
• comparison track: 10-11m

• piste d'essai: 32-35m
• piste de comparaison: 18-20m

Medium speed braking (60Km / h):

• test track: 32-35m
• comparison track: 18-20m

b. Slalom

Five studs are aligned at 5m from each other. The pilot uses the same elk distance to the test track and to the comparison track. The pilot passes smoothly between the five studs, without upsetting them, on the comparison track.

On the contrary, on the test track, with the same momentum, the pilot can pass only three studs and overturns the other two.

vs. Circular trajectory

• sur la piste d'essai le kart est nettement en survirage permanent
• sur la piste de comparaison, le kart est nettement en sous-virage permanent

The pilot tries to describe a circular trajectory around a fixed stud, the kart being in skid, the front of the kart being turned towards the center of the circle, a.rayon about 4 m:

• on the test track the kart is clearly in permanent oversteer
• on the comparison track, the kart is clearly in permanent understeer

d. Subjective tests

The track is totally wet. Two drivers successively perform the movements and maneuvers of their choice over the entire surface of the test track and the comparison track. At the end of these driving tests, the two pilots estimate that they experience on the track of comparison the usual sensations of driving on wet surfaces. On the other hand, they feel that they feel very similar to those experienced when driving on ice on the wet test track.

Example 5: Braking tests with a passenger vehicle

The vehicle used is a Porsche 911 Carrera equipped with summer tires in perfect condition. The vehicle is equipped with all the electronic driver assistance devices mounted in series by the manufacturer.

The driver successively brings the vehicle to 50Km / h and then 60Km / h on the momentum area and brakes as much as possible from a mark placed respectively on the test track and on the comparison track, up to 'stop.

The braking distance of the Porsche is about 1m to 50Km / h and about 2m to 60Km / h on the test track.

The results set out in the examples above make it possible to draw the following conclusions:
the three tested mixes have slip values such that a wearing course made from them offers a much lower adhesion than a road-tested wearing course. On the other hand, the Marshall creep and stability characteristics of the mixes 1 and 2 show that wearing courses made using these can withstand, without rutting or noticeable deterioration, the maximum stresses exerted by road vehicles, or by racing cars weighing several hundred kilos and several hundred horsepower.

Asphalt # 3 has an even higher slip. Its stability a little lower than the previous two is more for the realization of kart tracks or tracks for teaching driving. With regard to this latter application, it is appropriate in particular to observe that the cost of a coating comprising a traditional HMT layer and a wearing course according to the invention can be estimated at respectively 18 Swiss francs / square meter for the support layer and 17 Swiss francs / square meter for the wearing course, for a total of around 35 francs / square meter of pavement. By way of comparison, a slippery runway made of a concrete support layer with a synthetic resin coating is approximately 80 Swiss francs / square meter for the concrete support and approximately 30 francs / meter. square for the resin coating, a total of 110 Swiss francs per square meter. In addition, the coating according to the invention requires practically no maintenance for several years, whereas in the case of the track coated with a synthetic resin coating, the latter must be changed at least once a year and even more if the use of the installation is permanent.

Claims (15)

1. A non-draining coated material, intended for making the wearing course of a track for learning to drive and/or for races of motor-driven land vehicles under low adherence conditions, said coated material comprising mineral aggregates and at least one bituminous binder, said mineral aggregates consisting of more than 90% of materials of aggregate class 0/4 and the binder/coated material content being 8.5 ± 1% by mass, characterized in that said mineral aggregates comprise a high proportion of rolled sand and have an undersize greater than or equal to 95% with the 2.8 mm analysis sieve.
2. The coated material according to claim 1, characterized in that said mineral aggregates comprise 30-50% of rolled sand.
3. The coated material according to one of claims 1 or 2, characterized in that said mineral aggregates comprise more than 10% by mass of fines.
4. The coated material according to one of claims 1-3, characterized in that said aggregates have grain size values comprised within the following limits: Analysis sieve (mm) Undersize (% by mass) 4 98-100 2.8 98-100 2 85-95 1 60-70 0.5 40-50 0.25 25-35 0.125 15-25 0.09 10-20
5. The coated material according to claim 4, characterized in that said aggregates have the following grain size values: Analysis sieve (mm) Undersize (% by mass) 2.8 Greater than 97 2 Greater than 87 1 Greater than 65 0.5 Greater than 42
6. The coated material according to one of claims 1-5, characterized in that said bituminous binder comprises a 50/70S bitumen or a 55/70 bitumen.
7. A method for making a track with a roadway comprising a bituminous concrete coated material for learning to drive and for races of motor-driven land vehicles under low adherence conditions, characterized in that said track is provided with a wearing course in bituminous concrete consisting of a coated material according to one of the preceding claims.
8. The method according to claim 7, characterized in that said coated material is provided with a wearing course in bituminous concrete consisting in a non-draining coated material, the slipperiness of which is comprised between 55 and 68 SRT units.
9. The method according to claim 8, characterized in that slipperiness is comprised between 60 and 67 SRT units.
10. The method according to one of claims 7 to 9, characterized in that said coated material has a content of residual voids of 4±2% and a content of filled voids of 85±6%.
11. The method according to claim 10, characterized in that said non-draining coated material of the wearing course has a Marshall stability of more than 10kN and a Marshall creep of less than 3.5 mm.
12. The method according to one of claims 7 to 11, characterizing that the thickness of said wearing course is comprised between 7 and 35 mm and in particular between 15 and 30 mm.
13. A track for learning to drive and/or for races of motor-driven land vehicles under low adherence conditions, said track having a roadway comprising a coated material of bituminous concrete, obtained by a method according to one of claims 7 to 12.
14. The track according to claim 13, said coated material comprising one or more supporting layers in bituminous concrete under said wearing course.
15. The track according to claim 14, laid out as a closed circuit, in particular so as to form a race circuit.

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