Track for cycling and / or roller sports and process for its construction

Abstract

The invention relates to a cycling and / or roller sports track (10) comprising a circuit (12) in a base area. The circuit comprises a sequence of at least one element selected, for example, from rollers (14) and curves (16). The circuit (12) has gradients, even exceeding 50°. The circuit comprises a subbase (26; 26a, 26b) of one or more layers and above it a paving (28) of one or more layers. To optimise the mechanical performance and reduce erosion effects of the circuit (12), the paving comprises an aggregate, a hydraulic binder, and a stabiliser adapted to increase the binding force between the aggregate and the hydraulic binder, in particular a stabiliser comprising at least one element selected from the group consisting of silicates, carbonates and phosphates and optionally aluminates. A related process for the construction of the cycling and / or roller sports track, i.e. of its circuit, is also described.

Description

[0001] TITLE: TRACK FOR CYCLING AND / OR ROLLER SPORTS AND PROCESS FOR ITS CONSTRUCTION

[0002] Applicant: TRAIL UP di Campesato Andrea, Via Capitello 9M - 36048 Barbarano Mossano (VI), Italy

[0003] TECHNICAL FIELD

[0004] The present invention relates to a track for cycling and / or roller sports comprising:

[0005] (a) a base area in which there are arranged

[0006] (b) a circuit comprising at least one element, preferably a plurality of elements, selected from rollers, curves, ramps, obstacles and flat jumps and wherein gradients are present, which preferably also reach more than 50°; and preferably (c) areas enclosed by sections of the circuit, preferably by sections of a loop circuit,

[0007] wherein the circuit is made in layers comprising as layers

[0008] (b-1) a single- or multi-layered subbase; and above it

[0009] (b-2) a single- or multi-layer paving.

[0010] The invention also relates to a process for the construction of the track.

[0011] STATE OF THE ART

[0012] Different types of tracks for cycling and / or roller sports are known. A pump track is a track built specifically for cycling. It has a circuit of rollers or undulating hills (i.e. climbs and descents), elbows or parabolic curves, and elements designed to be completely travelled by cyclists "pumping" - generating momentum with upward and downward body movements, instead of pedalling or pushing. The goal is to become faster and faster through upward and downward pumping movements of the body and to maintain this momentum for several laps. It was originally designed for the mountain bike and BMX scene, and now, thanks to the concrete and / or asphalt constructions, it is also used for skateboarding, roller skates and scooters, and accessible to wheelchair users.Most pumping tracks connect a series of rollers to curves with steep kerbs that bring riders back. They are generally constructed of concrete or asphalt.

[0013] The roots of pump tracks go back to the 70s and 80s; modern race tracks in their current form, however, were bom in Australia around 2003. Since then, pump tracks have spread around the world and evolved into various forms, including modular pump tracks and mobile pump track solutions.

[0014] A jump line, on the other hand, is a specific route or track, often within a trail park or mountain bike area, designed with a series of jumps, ramps and obstacles that allow bikers to literally fly in the air. These lines offer the opportunity to improve the jumping skills and can vary in difficulty and length, and often include different types of jumps, such as table tops, step-ups, step-downs, and doubles.

[0015] Another example for a cycling track is a skill park for mountain biking.

[0016] Skill parks are usually equipped with a variety of structures that offer singletrack sections, climbs, descents, rocks, roots, and other off-road obstacles. Obstacles are often wooden objects placed on the actual track.

[0017] Corresponding tracks also exist for roller sports. Often, cycling tracks can also be traversed with wheeled elements, as tracks for wheeled sports can be traversed by various types of bicycles.

[0018] Trails on compacted earth would be more eco-sustainable than on bituminous surfacing, but have the disadvantage of dust or mud formation as a result of weather events or ruts in areas with concentrated traffic. As a result, compacted earth tracks are subject to rapid deterioration and require frequent and expensive maintenance.

[0019] DISCLOSURE OF THE INVENTION

[0020] The object of the invention is to overcome the aforementioned drawbacks and to propose a track for cycling and / or roller sports that is both environmentally friendly and of a high mechanical resistance so as to reduce the phenomena of dust, smud, ruts and the like. Another object of the invention is to provide a process for the construction of such a track for cycling and / or roller sports. Further objects or advantages of the invention will become apparent from the following disclosure.In a first aspect of the invention, the object is achieved through a track for cycling and / or roller sports as initially defined, wherein the paving comprises

[0021] (i) an aggregate;

[0022] (ii) a hydraulic binder; and

[0023] (iii) a stabilizer adapted to increase the binding force between aggregate and hydraulic binder, in particular a stabilizer comprising at least one element selected from the group consisting of silicates, carbonates and phosphates and optionally aluminates, preferably a stabilizer comprising silicates, carbonates and phosphates.

[0024] In a preferred embodiment of the invention, the stabilizer comprises silicates, carbonates and sodium and / or potassium phosphates. The phosphate is preferably a tripolyphosphate. Preferably, the stabilizer comprises sodium silicate, sodium carbonate, potassium chloride and sodium tripolyphosphate. These inorganic salts optimize, as will be illustrated below, the binding effect between the hydraulic binder and the aggregate material. The person skilled in the art, with their general knowledge, determines the most suitable mixtures for their purposes. Alternatively, the paving could be composed of a compacted aggregate provided with or without a hydraulic binder wherein at least a surface layer of the paving is impregnated with crosslinking polymers that bind the present components to one another with the result of reducing the formation of dust. Suitable compounds may be, for example, a mixture of at least one acyclic aliphatic compound and at least one cyclic aliphatic compound. Preferably, the acyclic aliphatic compound comprises at least one linear alkane, a branched alkane, or a combination thereof, and the cyclic aliphatic compound comprises at least one cycloalkane, an alicyclic compound, or a combination thereof. Advantageously, the compounds are combined in a synthetic fluid comprising: 5 - 75 weight percent of one or more methyl-branched alkanes; 5 to 70 weight percent of one or more dimethyl -branched alkanes; and 5 to 60 weight percent of one or more trimethyl -branched alkanes. Preferably, at least one cyclic aliphatic compound comprises one or more dimethyl-branched alkanes with cyclopentyl or cyclohexyl rings, wherein the synthetic fluid comprises in the range of from 0.5 to 60 percent by weight of one or more dimethyl-branched alkanes with cyclopentyl or cyclohexyl rings. Advantageously, the synthetic fluid comprises at least one binder, and precisely a carboxylic acid or a polyolefin. In a variant of the invention, the paving is an integral part of the subbase layer. However, theresults obtained with this system are not completely satisfactory from the point of view of the object of the invention.

[0025] The track for cycling and / or roller sports, advantageously, is selected between a pump track, which is particularly preferred, and a jumping line and a skill park.

[0026] Aggregate generally refers to a soil, for example the soil present in situ of the construction site of the pump track. The soil may comprise gravel, crushed stone, sand and other materials of varying grain size. For example, silts, clays, pumice may also be present. An ideal aggregate is a crushed quarry material without the presence of organic material, so in other words a preferred material comprises predominantly crushed stones and / or rocks. Waste materials of construction or road origin (asphalts) that can serve as aggregate are not to be excluded and are always to be considered environmentally friendly as they reuse waste materials by repurposing them. Various mixtures between the above-mentioned materials are also conceivable. Plastics may also be added, thus various forms of natural and / or synthetic polymers.

[0027] Unsuitable aggregates usually have a high clay content and a high organic fraction content. Suitable aggregates, on the other hand, include “unwashed quarry run”, “graded quarry aggregate”, and “crusher screenings”. The diameter of the granules should not exceed 1 / 4 or 1 / 3 of the thickness of the paving; the ideal aggregate includes granules of size from 16 mm to 20 mm.

[0028] However, granular mixtures that also include small portions of clay are to be excluded from the usable soils. A stabilised mix could be composed as follows: 60% Saulo (decomposed granite), 30% calcareous gravel and sand, 10% silty sand.

[0029] In the preparation of the paving and in the determination of the amount of water to be added it is to be considered that in order to obtain optimal compaction performance, the dry density should decrease and the moisture increase when the hydraulic binder is added.

[0030] The aforesaid silicates, carbonates and phosphates are preferably sodium and / or potassium silicates, carbonates and phosphates. In a highly preferred variant of the invention, the stabilizer comprises, or in an embodiment of the invention is composed of, sodium silicate (ISfeSiCh), sodium carbonate (ISfeCCh), potassium chloride (KC1) and sodium tripolyphosphate (NasPsOio).The addition of a hydraulic binder to the aggregate improves the mechanical performance of the aggregate, but in light of the objects of the invention is still not satisfactory. With the presence of the stabilizer, better results are obtained and it is possible to create compacted earth tracks that do not have the aforementioned disadvantages. The stabilizer in the form of a mixture of salts as defined above has a cleansing power and helps to disaggregate the micelles of the aggregate to make them coatable by the hydraulic binder, thus increasing the binding force between the aggregate and the hydraulic binder. Alternatively, the stabilizer can also be defined as an element adapted to reduce the formation of dust in the mixture between aggregate and hydraulic binder.

[0031] Some substances present in the aggregate may inhibit or dramatically delay the curing reactions of hydraulic binders. The humic substances, having many complexing agents and a high ion exchange, hinder the effectiveness of the binder. Slits and clays tend to induce a plastic behaviour to the compound and reduce the effectiveness of the binder by introducing an excessive amount of micro-particles. Fatty elements reduce the ability of the binder to adhere to aggregates. Organic impurities alter the hydration kinetics of the binder, hindering the curing process. Humic substances tend to be very hygroscopic, withdrawing water from the binder. Acids unpredictably delay the reaction of the hydraulic binder. To further optimize the effect of the binder, an aggregate that does not contain organic materials is preferable.

[0032] The stabiliser promotes the removal of humic, organic and clayey substances from the surface of the aggregates. The stabiliser transforms humic and earthy elements into colloidal compounds. In addition, the stabilizer deactivates other chemical processes responsible for inhibiting the action of the binders. The stabiliser makes the earthy particles wettable by dispersing the organic, humic and clay substances present. The stabiliser removes the organic films covering the aggregate particles with a cleansing action.

[0033] The stabilizer allows, in particular, the hydraulic binder to bind and combine with the earthen aggregates in which the plasticity index of clay content is less than or equal to 10, consequently increasing the compressive strength performance of the road structure. To correctly perform their cohesive function, hydraulic binders need to homogeneously "wrap" the material to be bound and distribute over the entire surface. An ideal aggregate allows limiting the quantity of the hydraulic binder and has a low specific surface (limited very fine quantities) and a good particle size distribution. The stabilizer comprising one or more inorganic salts indicated abovehas an aggregation power even in the presence of silts, clays and humus. It neutralizes the organic films present in the soil which, where present in high quantities, would not allow proper hydration thereof with a consequent reduction in the maximum compaction degree achievable. Thanks to the clear transparent colour of the stabiliser, the colour of the aggregate is not altered. The surface of the paving obtainable with a mixture of aggregate as defined above, hydraulic binder and a salt-based stabiliser is also very smooth.

[0034] Once the adhesion condition has been created on the surface of the aggregate, the action of the stabilizer is directed towards the free water present in the materials to be stabilized, responsible for the phenomena of plastic deformation, which is chemically absorbed through the hydration of the oxides present in the hydraulic binders. This generates complex stable hydrated salts capable, even after a few hours, of modifying the physical and mechanical behaviour of the treated soils.

[0035] Advantageously, the hydraulic binder comprises hydraulic lime, cement, such as Portland cement, marl limestones, possibly even with clayey parts. Generally, the hydraulic binder comprises calcium oxide. Calcium hydroxide and / or calcium silicates and / or calcium aluminates may also be present. The hydraulic binders reduce the presence of water, promote ion exchange and flocculation and promote a pozzolanic reaction. The plasticity of the paving mixture is adjustable with the type and amount of the hydraulic binder, but also with the type of aggregate. The finer the aggregate, the more elastic the mixture is for the paving.

[0036] In an advantageous embodiment of the invention, the paving comprises per 1 m3of aggregate 800 g - 1,200 g, in particular 950 g - 1,050 g, preferably about 1,000 g of said stabilizer and from 150 to 250 kg of a hydraulic binder, preferably > 175 kg of a hydraulic binder, more preferably > 200 kg of a hydraulic binder. With an amount > 200 kg, an amount of stabilizer > 1,200 g could also be envisaged.

[0037] The ratio between hydraulic binder and stabilizer is advantageously chosen in such a way as to guarantee the following minimum performance in the paving: a uniaxial compressive strength (C.N.R. standard 29) at 7 days of hardening not less than 20 MPa and an indirect tensile strength (C.N.R. standard 97) at 7 days of hardening not less than 1.7 MPa.

[0038] The ground paving stabilized according to the invention has a "compacted earth" effect and has a virtually zero environmental / landscape impact. Aggregates, such as the "quarry run mix" witha 0 / 20 mm undersize and a limited fine, silts and clays fraction (< 10%), for example, proved suitable for a track for cycling and / or roller sports, in particular for a pump track. The minimum thickness of the paving is preferably 8 cm, more preferably 10 cm, but advantageously does not exceed 15-20 cm.

[0039] The paving according to the invention exhibits adequate permeability, is environmentally friendly, recyclable and frost-resistant.

[0040] During curing (at least 4-5 days) of the paving, therefore after its laying and compaction, it is preferable to maintain moisture through moistening actions and / or the application of covers. Typical variables for a suitable aggregate are for example: a regular "stabilised aggregate" type particle size distribution in the fraction 0 / 20 - 0 / 30, for example also 0 / 25. It should be noted that in aggregates with a 0 / 30 fraction or in materials with a small fines fraction, the coarse fraction may cause segregation (honeycombing) during processing, which should advantageously be identified and eliminated as these constitute potential ravelling points in the paving. An aggregate in fraction 0 / 20 is therefore preferable, which guarantees better homogeneity in the spread and is generally more easily workable.

[0041] An exemplary suitable aggregate has the following characteristics: a Los Angeles value: LA < 30, a sand equivalent SE > 35 and a plasticity index PI < 6 and less than 10% fraction passing the 0.063 mm sieve. In the case of low-stress paving, the following values are also sufficient: Los Angeles value: LA < 40; sand equivalent SE > 30, plasticity index PI < 10 and less than 12% fraction passing the 0.063 mm sieve.

[0042] The Los Angeles test consists of determining the abrasion resistance of rocks or aggregates by rolling an aggregate sample together with steel balls inside a rotating cylinder. The Los Angeles coefficient is calculated based on the weight loss of the material after the test. The reference standard is UNI EN ISO 1097-2. The sand equivalent, for example, can be determined according to the standard UNI EN 933-7.

[0043] Advantageously, the hydraulic binder / stabilizer dosage is chosen so as to obtain a uniaxial compressive strength (CNR 29) at 7 days hardening > 7 MPa, more preferably > 10 MPa, 12 MPa or 15 MPa. Preferable values for the indirect tensile strength (CNR 97 standard) at 7 days of hardening are > 1 MPa, > 1.2 MPa; > 1.3 MPa or > 1.7 MPa.In areas of steep gradients or in curves with reduced radius, the uniaxial compressive strength is preferably > 15 MPa, or even > 20 MPa. For the subbase in a plate load test (CNR 146 standard), bearing capacity values > 50 MPa are desirable, for example also values > 80 MPa. A suitable exemplary thickness for the subbase is 50 cm or higher, such as 80 cm. Ideally, paving is carried out at a temperature T = 5°C - 35°C. The compaction degree according to ASTM D 1557 achieved during compaction of paving should advantageously be > 95%.

[0044] The paving is ideally positioned directly above said subbase, which usually, but not necessarily, consists mainly of a coarser stabilised one with particles with dimensions up to 80 mm that can vary in thickness based on the soil present on site, but which will advantageously have a thickness ranging from 25 cm to 60 cm, to which are added the thicknesses necessary for the creation of curves, rollers etc., then another 40 - 80 cm on average. The thickness is obviously reduced in the positions where the circuit is excavated.

[0045] If necessary, water drains are preferably provided according to the needs of the route itself. Within preferred embodiments of the invention, the circuit comprises gradients from 40° to 65°, advantageously gradients between 55° and 65°. The gradients are preferably within the radius of the curves, but also on the rollers. These gradients require high mechanical performance of the paving that can be achieved by selecting quantities of hydraulic binder over 175 kg, but also > 200 kg or even up to 250 kg for 1 m3of aggregate. A maximum limit for the amount of binder in a preferred embodiment of the invention is defined to be around 250 kg. The steep gradients are found mainly within the curves and on the jump ramps.

[0046] The amounts < 175 kg, more preferably < 200 kg are ideal for the construction of high gradients of tracks for cycling and / or roller sports and are surprising with respect to the test results determining the compression or indirect tensile strength which indicated for amounts over 175 kg a reduction in the mechanical performance of the relative mixtures. The choice of quantities > 175 kg is therefore contrary to the teaching of the test results.

[0047] For example, to indicate certain paths within the circuit, said paving comprises in one embodiment of the invention coloured pigments. To make the circuit usable at night without external lighting or at least only with "dim lighting", the paving includes fluorescent or phosphorescent pigments in a preferred embodiment of the invention. The various pigments can also be added to indicate elements of different dangerousness or difficulty or simply toobtain particular aesthetic effects. The paving mixture can easily be provided with these pigments before its application on the subbase.

[0048] Preferably, the areas enclosed by sections of the circuit are equipped with turf and a robotic lawnmower and optionally a relative docking and charging station for said robotic lawnmower. The presence of a robotic lawnmower simplifies the maintenance of turf, and this also during the use of the track for cycling and / or roller sports.

[0049] To further increase the mechanical strength of the paving, it is equipped in a preferred embodiment of the invention, in particular in areas of high gradient and high stress, with a mixture of polymeric fibers, for example polyolefin fibers, and / or one or more structural meshes, for example in basalt or glass. Excessive or abrupt changes in gradient of the circuit may be made more resistant to mechanical friction by the addition of fibre mixtures and / or structural meshes with a reinforcing function.

[0050] To increase the stability of the circuit, expansion joints may be provided in variants of the invention. In stabilized earth paving according to the invention, generally characterized by a low binder content and a lower stiffness than a concrete paving, it can be considered to omit expansion joints or to reduce their frequency.

[0051] Preferably, the paving thickness of the track for cycling and / or roller sports varies from 10 cm to 20 cm, in particular from 12 cm to 15 cm. The thickness will be chosen by the person skilled in the art based on the abrasion expected during use.

[0052] To create the circuit path and make it stable, it is advantageous to provide a containment arranged under the subbase. Containment is useful to avoid settlement. Advantageously the containment is a non-woven fabric layer (e.g. GeoTex) which traces the circuit path and marks the shape of the pump track subbase.

[0053] The subbase advantageously comprises an aggregate as specified above, usually with larger particle size. It is generally devoid of a hydraulic binder, but the presence of a hydraulic binder to strengthen the structure of the subbase cannot be excluded.

[0054] A second aspect of the invention relates to a process for the construction of a track for cycling and / or roller sports comprising the following steps, not necessarily in the order indicated:(I) preparation of a stabilised subbase reflecting the layout of a desired circuit, which is preferably obtained by making a base stabilised subbase structure in which the conformation of the desired circuit is excavated;

[0055] (II) mixing

[0056] a stabilizer adapted to increase the binding force between aggregate and hydraulic binder, in particular a stabilizer comprising at least one element selected from the group consisting of silicates, carbonates and phosphates and optionally aluminates, preferably a stabilizer comprising silicates, carbonates and phosphates, of a desired amount of water,

[0057] of a hydraulic binder and

[0058] of an aggregate to obtain a paving mixture,

[0059] (III) creating on said stabilized subbase with the paving mixture obtained at the end of step (II) a paving above said subbase.

[0060] In a preferred variant of the invention, coloured pigments and / or fluorescent or phosphorescent pigments are added to the mixture in step (II).

[0061] Advantageously, the subbase is initially created as a base structure in which the circuit is excavated. For example, if an "8"-shaped section is desired, the basic structure, also called "zero", will be a parallelepiped, where the "8"-shaped section can be fit within it and is obtained by excavating and removing the relative portions of material.

[0062] Advantageously, a containment layer is provided underneath the subbase, in particular in nonwoven fabric. Preferably, during the construction of the subbase of the track for cycling and / or roller sports, a first stabilised layer with a thickness of up to 25 mm is applied over the containment layer, subsequently, further paving layers are applied which are then compacted, advantageously with 400-500 kg vibrators, every 35 - 40 cm thick. Once the desired number of layers has been created, the excess material is removed to create the desired circuit.

[0063] In an embodiment of the invention, the subbase is prepared in several layers and when a certain thickness of the layers has been reached, their compaction is continued, preferably with a paver. After compacting, the application of layers is repeated, which are then compacted once a certain thickness of the layers not yet compacted has been reached. This procedure is repeated until the desired thickness of the subbase is reached. Alternatively, compactions can be carried out after each layer applied. In this way, the circuit is obtained in the form of a raised structure or berm.Subsequently, the desired circuit shapes, such as rollers and curves, are excavated in the obtained subbase structure. In this way, a well -compacted subbase is ensured throughout the entire circuit. An excavator can be advantageously used to excavate the desired shapes. Once the desired surface shape of the circuit has been defined, the paving is applied. This procedure also makes it possible to obtain well -compacted curve and roller structures, including in areas of steep gradients that would otherwise be difficult to construct.

[0064] In other words, an advantageous embodiment of step (I) of the preparation of the subbase provides for the following steps:

[0065] (1-1) one or more layers of the material for the subbase in the circuit area is / are applied, preferably on a containment, such as a non-woven fabric;

[0066] (1-2) the obtained structure is compacted when a desired thickness has been reached; (1-3) steps (1-1) and (1-2) are repeated until the desired overall thickness of the subbase is obtained;

[0067] (1-4) the desired shapes of the circuit, such as rollers and curves, are excavated in the base subbase thus raised.

[0068] Preferably, in the preparation of the mixture of step (II) one starts with the solution of the stabilizer in water, followed by the addition of the hydraulic binder and then proceeds with the addition of the mixture obtained to the aggregate.

[0069] Alternatively, it is possible to prepare a dry mixture, in particular a pre-packaged mixture, for example in bags, which includes aggregate, hydraulic binder and stabiliser. In the case of application or construction of the pump track, the mixture arrives ready and pre-packaged, for example in bags, on site and water is added to the dry mixture. Optionally, the dry mixture may include one or more of the following components: polymer fibres, coloured pigments, fluorescent or phosphorescent pigments, auxiliary materials or additional additives as described below.

[0070] The paving is advantageously compacted, as is the subbase. In a preferred embodiment, the paving is constructed of multiple layers that are compacted individually or in groups as certain thicknesses are achieved. The same is advantageously true of the subbase.

[0071] Preferably, the paving is compacted by hand to obtain optimal mechanical characteristics.The type of aggregate, hydraulic binder and stabilizer and their ratio applied during the process according to the invention, advantageously correspond to what is said above for the paving of the track for cycling and / or roller sports. An amount of water to obtain a paving mixture suitable for layering advantageously varies from 601 to 1001, preferably from 801 to 1001 for each m3of aggregate.

[0072] In a preferred embodiment of the invention, the ratios between stabilizer and hydraulic binder to be introduced in 1 m3of aggregate and the amount of water to prepare the paving mixture are optimized by determining at least one of the following parameters and / or by carrying out at least one of the following tests:

[0073] - particle size analysis,

[0074] - the Atterberg consistency limit to determine plasticity;

[0075] - a tamping or compaction test at varying moisture content to determine the maximum dry density and the optimum moisture content for improved compaction;

[0076] - the California Bearing Ratio (CBR) and / or tests for determining compressive strength and / or indirect tensile strength, preferably at 7 and / or 28 days.

[0077] For particle size analysis, the ASTM D422-63 (R 2007) standard by sieving and sedimentation of the aggregate or the CNR BU 23 / 71 standard, A.G.I. recommendations 1994, is applicable. A reference standard for the determination of the Atterberg consistency limit is ASTM D4318- 10 or the U.N.I. 10014 standard. The classification then takes place according to H.R.B. Highway Research Board AASHTO M 145-2003. A compaction test is the Proctor test, A.A.S.H.T.O. modified, according to the C.N.R. B.U. A. XIINo. 69 standard or ASTM D 1557 standard. The CBR index can be determined according to the CNR UNI 10009 standard. Tests for determining compressive strength and indirect tensile strength, respectively, may be carried out in accordance with standards UNI 6132.72 and C.N.R. 97, preferably at 7 and / or 28 days. The compressive and bending strength of the binder can be measured according to the UNI EN 196-1 standard.

[0078] The natural water content, where necessary, is advantageously determined according to the UNI CEN ISO / TS 17892.1 standard. The natural water content, where required by the standards, may be determined by calculating the difference in weight of a sample in its natural state and after drying at 110°C in an oven until a stable weight is reached.The bearing ratio determines compactness even in the presence of fine fractions and takes into account the intended use of the material, the risks of saturation from water ingress (gravitational and / or capillary), and the expected compaction degree.

[0079] The purpose of the particle size analysis is to identify the size class of the aggregate by determining the dry weight percentages of the components of the initial sample. Sieve particle size analysis classifies the portion of soil with particles > 0.075 mm or < another desired value (e.g. 0.063 mm) using sieves of different mesh sizes, while sedimentation particle size analysis classifies, on the basis of Stokes' law, particles < 0.075 mm or < another desired value (e.g.

[0080] 0.063 mm) by measuring the settling velocity by means of a hydrometer.

[0081] The Atterberg consistency limit indicates the threshold water content at which a transition in the physical state of the soil occurs, enabling classification of the soil as solid, semi-solid, plastic or liquid and determination of the plasticity index and liquidity index on a diagram known as the Casagrande chart. The type of clay can be determined. In the case of the paving mixture, it is useful to perform the test on wet material cured for 7 days. The plasticity index (PI) represents the range of water content within which the soil remains in a plastic state. Its value increases linearly as a function of the percentage of clay present in the soil, with a different gradient depending on the type of clay minerals contained therein. Table 1 correlates the soil type with the PI index:

[0082] Table 1 Soil PI Index

[0083] Non-plastic 0 - 5

[0084] Little plastic 5 - 15

[0085] Plastic 15 -40

[0086] Very plastic > 40

[0087]

[0088] Suitable binders for non-plastic aggregates are, for example, based on hydraulic limes and inorganic oxides For the stabilization of materials with a silty-clay component, the use of the stabilizer is particularly useful. Plasticity index decreases markedly with increasing percentage of hydraulic binder (CaO).The Proctor compaction test (modified AASHTO) compacts the soil with a free-fall rammer. The modified test is applied for subbase soil and paving materials. Specified quantities of dried and re-wetted soil at a known moisture content are placed in layers in a cylinder and compacted with the rammer using a predetermined number of blows, for example 56 blows. The operation is repeated for a desired number of layers. The test must reproduce the order and times of onsite processing. Various degrees of moisture are tested. A part of the compacted material is tested for moisture. From the graph plotting dry density against water content, the optimum moisture content for maximum compaction is obtained at the peak of the curve. Advantageously, for the paving mixture, the samples are matured 24 hours before carrying out the test.

[0089] The California Bearing Ratio (CBR) is the ratio, expressed as a percentage, between the load required to drive a piston of standardised dimensions into a specimen confined in a metal mould and a reference load. The CBR index is used to determine the bearing capacity of the soil and provides the CBR index for dimensioning the foundation layers of pavings. The specimens for the determination of the CBR index can be tested in the press immediately after compaction (Instantaneous Bearing Ratio, IBR) or after compaction and soaking for 96 hours (but after initial curing of 7 days) in order to simulate complete saturation of the soil (post-saturation bearing ratio). Swelling of the sample after addition of water is also determined.

[0090] A compaction of the paving, for example by means of a paver, reduces the voids present in the spread by making intimate contact between the particles, favoured by a correct water content and allowing the binder to carry out its action between the particles. Compaction ideally continues until the roller marks disappear and a planar and homogeneous surface is obtained. In order to maximise the effectiveness of the compaction operation, it is advisable that the paving is confined so that no displacemen towards the outside is possible at the edges.

[0091] In the preparation of the paving, additions of auxiliary materials with anti -evaporative action are conceivable for the surface treatment of the pavings to improve permeability, to achieve for example an runoff coefficient < 0.5. The auxiliary will be advantageously applied by low pressure airless spraying on the surface of the paving, immediately following the end of the laying and compaction thereof, before the surface of the paving can be subjected to premature drying. To speed up setting, specific accelerators are conceivable. Another adjuvant could bean anti-dust consolidating additive which operates through saturation and consolidation of the fine fraction of the aggregates, such as for example the above synthetic fluid.

[0092] Additives to further improve the rheology of the natural aggregate-conventional hydraulic binder mixture are also envisageable, facilitating its laying through a water-retaining action that promotes proper hydration of the binder and enables improved adhesion between the binder paste and the aggregate. In addition, such an additive acts as a water reducer, to the total benefit of the mechanical resistance and durability characteristics of the paving made and resistance to freeze-thaw cycles through the reduction of the water / binder ratio.

[0093] If, on the other hand, the paving is made anti-dust using the above crosslinking polymers, the relative synthetic fluid is applied on the surface of the paving layer formed by aggregate with or without compacted hydraulic binder and placed on the subbase layer.

[0094] A third aspect of the invention relates to the use of the cycling and / or roller sports track by riding on it with bicycles, roller skates, scooters, skates, mountain bikes or BMX bikes.

[0095] Advantageously, the use of the cycling and / or roller sports track according to the invention comprises mowing the grass in the areas enclosed by sections of the cycling and / or roller sports circuit.

[0096] A fourth aspect of the invention relates to a trail park comprising at least one cycling and / or roller sports track according to the invention, in particular selected from a pump track, a jump line and a skill park. In a preferred embodiment of the invention, the trail park may also comprise at least one "compacted earth" track not provided with gradients as defined in the first claim, in particular a respective skill park.

[0097] The features described for one aspect of the invention can be transferred mutatis mutandis to the other aspects of the invention.

[0098] The industrial application is obvious insofar as it has been possible to obtain a stable and compact cycling and / or roller sports track with high mechanical properties, even in areas of steep gradients, and wherein the typical drawbacks of "compacted earth" constructions, such as dust, mud, rutting and consequent water ponding, have been significantly reduced, thereby considerably reducing maintenance interventions.Said objects and advantages will be further highlighted in the disclosure of preferred examples of embodiments of the invention given by way of example only.

[0099] Variants and further features of the invention are the subject matter of the dependent claims. The description of the preferred exemplary embodiments of the cycling and / or roller sports track, the process for its construction and its use, and the trail park according to the invention is given by way of non-limiting example with reference to the accompanying drawings. In particular, unless otherwise specified, the number, shape, size and materials of the system and of the individual components may vary, and equivalent elements may be applied without leaving the scope of protection defined by the claims.

[0100] BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Fig. 1 represents in a perspective view an exemplary embodiment for a pump track. Fig. 2 represents in a cross-sectional view the circuit of the pump track according to figure 1.

[0102] Fig. 3 represents for a section of the pump track circuit according to figure 1 the construction of its subbase.

[0103] Fig. 4 represents in a perspective view a trail park.

[0104] DESCRIPTION OF PREFERRED EMBODIMENT EXAMPLES

[0105] Fig. 1 represents in a perspective view an exemplary embodiment for a pump track 10 comprising a circuit 12 to be travelled for example with a bicycle (not shown). The circuit 12 has rollers 14 as well as several curves 16 whose inner radii may have gradients reaching up to 65°. Grassed areas 18 can also be noted. To facilitate the maintenance of grassed areas, one or more robotic lawn mowers 20 may be provided with their docking and charging station(s) (not shown).

[0106] Fig. 2 represents in a cross-sectional view the circuit 12 of the pump track 10 according to figure 1. The circuit 12 is constructed in layers: from bottom to top are observed, an in situ soil layer 22, a non-woven fabric layer 24 that serves to stabilize and contain the circuit 12 and create a barrier with respect to the in situ soil 22, a stabilised layer 26 of coarse particle size anda paving layer 28 of finer particle size. The assembly of layers is contained by a kind of kerb 30 on which vegetation 32 may be provided.

[0107] Fig. 3 represents for a section of the circuit 12 of the pump track 10 according to figure 1 the construction of the subbase 26. The figure shows in the same drawing three phases I, II and III of the construction of the subbase 26. A non-woven fabric 24 is laid in the area provided for the circuit 12 of the pump track 10. A first sequence of stabilised layers 26a is applied (phase I) and compacted with a paver 34. In a subsequent phase II, a further plurality of layers 26b is applied and compacted with a paver 34. After preparation of the subbase to the desired thickness or height, the circuit has the appearance of phase II and resembles a berm or a wide wall. In phase III, with an excavator 36, the desired shapes are given to the surface of the circuit 12, in this case a curve 16. The ridge 30 of the circuit (corresponding to the kerb shown in figure 2) is at least partly formed by excess material that slides laterally during construction of the circuit 12. It serves to support the circuit 12 and can then be provided with a turf or other plants. Fig. 4 represents in a perspective view a trail park 38 comprising a pump track 40, a jumping line 42 and a skill park 44.

[0108] Table 2 shows in an executive example the quantities suitable to obtain the composition of the paving mix:

[0109] Table 2 Description Measurement Quantity

[0110] unit

[0111] Quarry aggregate m31

[0112] Hydraulic binder kg 120-250

[0113] Stabilizer kg 1

[0114] Water 1 60-120

[0115]

[0116] An exemplary embodiment of the construction of a pump track circuit according to the invention comprises the succession of the implementation steps:

[0117] The subbase, i.e. the support, is made of a layer of stabilised granular aggregate of a thickness and compaction capable of withstanding the service loads expected for the stabilised earth paving to be constructed. Indicatively, it will have a thickness ranging from 25 cm to 140 cm. Containment and regulation works for surface runoff and infiltration water are provided. Once prepared and adequately compacted (advantageously following the layered approach describedabove), the subbase of the paving is ideally characterised by a bearing capacity, expressed as a deformation modulus (from a plate load test CNR 146 or a dynamic plate test), of not less than 80 MPa for frequently used pavings and not less than 50 MPa for more occasionally used, noncompetitive pavings.

[0118] An ideal soil aggregate for the paving is of the "graded stabilised aggregate" type with a specific particle size distribution in a single fraction of 0 / 20 mm. The presence of fine fraction should preferably be less than 10%. This type of aggregate, generally referred to as "fine quarry stabilised material", is the same as that used in subbase preparation works for industrial concrete or bituminous mix pavings; under the action of a paver, it compacts by void reduction and binds naturally.

[0119] The mixture is prepared by combining the hydraulic binder (hydraulic limes and inorganic oxides) and the stabiliser (the salts mentioned above) obtaining a binder-consolidant and aggregate in which the organic films are converted into colloidal substances that contribute to the cohesion of the base conglomerate, as well as to the improvement of the efficiency and mechanical performance of the finished paving. The paving mix is optimised with the tests illustrated above.

[0120] The aggregate, binder, stabiliser and water may be mixed using equipment known in the field, such as a mixing bucket or a self-loading concrete mixer. The stabiliser and water may be mixed first, followed by the addition of the hydraulic binder and subsequently the aggregate, or alternatively the components may be dry-mixed and the water added thereafter. The consistency of the final conglomerate shall be corrected, if necessary, by the further addition of suitably calculated water, until the desired consistency is obtained (a slightly moist mix), corresponding to the determined optimum moisture content.

[0121] One possible preparation involves dissolving 1 kg of stabilizer in 30 litres of water, and adding enough additional water determining the initial moisture according to ASTM D 2216. Too low a moisture value would prevent the setting of the binder, thereby compromising the quality of the entire work. Excessively high moisture is unsuitable for laying operations and for immediate compaction, and the resulting softening leads to a decrease in bearing capacity. To obtain suitable mixing, the rotation speed of the mixing device is adjusted; only slight inclinations of the container are advantageous.Ideally, the prepared mix should have a moisture content equal to or slightly higher than the optimum identified by a specific laboratory test (modified Proctor ASTM D1557). Experienced personnel determine the ideal moisture content by means of a manual test (hand showing damp marks). Upon completion of the mixing operations and verification of the correct moisture content and consistency of the mix, it shall be transported and transferred, by means of the equipment selected for this operation (tipper truck, concrete mixer truck, wheel loader, etc.), directly into the paver. Once the paver is positioned in the area where the soil conglomerate is to be laid, it shall be filled with the appropriate quantity of material to be spread

[0122] Once the paver is ready, the mixture will be extruded and then levelled on the previously prepared subbase. Minor surface irregularities produced by the paver shall be easily corrected using tools suitable for the purpose: hand shovel, wooden float, rake, etc. Once laying is complete, the paving shall be compacted using appropriate compaction equipment. The choice of equipment depends on the site logistics and the type of road paving being constructed, and compaction shall be continued until reaching a recommended compaction density of not less than 95% of that obtained from laboratory tests (modified AASHTO). Advantageously, a plurality of separate layers is applied and compaction is carried out between each layer or group of applied layers, also in the case of the application of the paving.

[0123] After compaction operations, the paving shall not be subjected to loads or trafficked for at least 4-5 days. In the presence of unfavourable thermo-hygrometric conditions liable to trigger rapid dehydration of the mix, effectively preventing proper hydration of the binder, it is necessary to keep the surface moist for at least 3-4 days, n particularly severe weather conditions, the treatment may be supplemented by spreading a protective sheet, usually a non-woven fabric, over the surface and wetting it (limiting the frequency to 1-2 operations per day). During the hardening of the paving, it is advisable to provide protection in winter with a polymeric sheet, for example in polyethylene, and in summer with a wet non-woven fabric.

[0124] So-called road crowns and / or side ditches are useful for the regulation of surface runoff.

[0125] Even after prolonged use, the paving remains free of potholes and mud in the event of rainfall, does not produce dust, and is eco-friendly and recyclable at the end of its service life.

[0126] The soils or aggregate materials used come from quarries or may contain recycled material. The materials used are preferably non-toxic and environmentally friendly. The paving improves thegeo-mechanical properties of the circuit (cohesion, internal friction angle, bearing capacity, resistance to water and frost, etc.), making it stable regardless of weather and environmental conditions.

[0127] Pavings produced according to the invention do not release harmful substances into the soil, are recyclable, and are classifiable as non-hazardous waste.

[0128] To identify suitable aggregates, it is useful to characterise them prior to use by means of a particle size analysis; the determination of the Atterberg limits; and the compaction test for determining the maximum dry density in relation to the optimum moisture content. Once a suitable aggregate has been identified, further tests are carried out on the mixture of soil and hydraulic binder-stabiliser combination: for example compressive strength tests (CNR 29) and indirect tensile strength tests (CNR 97, Brazilian test).

[0129] A suitable reference grading envelope for the aggregate is shown in the following table 3 : Table 3 Sieve (mm) Minimum envelope Maximum envelope passing (%) passing (%)

[0130] 63 100 100 31.5 100 100 25 95 100 20 80 100 16 65 100

[0131] 12.5 55 95 8 37 75 4 25 55 2 15 40 0.5 7 23 0.25 5 17

[0132]

[0133] 0.063 2 9

Claims

CLAIMS1) A track for cycling and / or roller sports (10) comprising:(a) a base area in which is arranged(b) a circuit (12) comprising at least one element, preferably a plurality of elements, selected from rollers (14), curves (16), ramps, obstacles and flat jumps and in which gradients are present, which preferably also reach more than 50°;wherein the circuit (12) is made in layers comprising as layers(b-1) a single- or multi-layered subbase (26; 26a, 26b); and above it(b-2) a single- or multi-layered paving (28);characterized in thatthe paving (28) comprises(i) an aggregate;(ii) a hydraulic binder; and(iii) a stabilizer adapted to increase the binding force between the aggregate and the hydraulic binder, in particular a stabilizer comprising at least one element selected from the group consisting of silicates, carbonates, and phosphates and optionally aluminates, preferably a stabilizer comprising silicates, carbonates, and phosphates.2) The track for cycling and / or roller sports (10) according to claim 1, characterized in that the paving (28) includes per 1 m3of aggregate 800 g - 1,200 g, in particular 950 g - 1,050 g of said stabilizer and from 150 to 250 kg of said hydraulic binder, preferably > 175 kg of said hydraulic binder, more preferably > 200 kg of said hydraulic binder.3) The track for cycling and / or roller sports (10) according to claim 2, characterized in that the paving (28) comprises > 200 kg of said hydraulic binder.4) The track for cycling and / or roller sports (10) according to any one of the preceding claims, characterized in that said circuit (12) comprises gradients from 40° to 65° which are preferably located in curves (16) of the circuit (12).5) The track for cycling and / or roller sports (10) according to any one of the preceding claims, characterized in that said paving (28) comprises coloured pigments and / or fluorescent or phosphorescent pigments.6) The track for cycling and / or roller sports (10) according to any one of the preceding claims, characterized by further comprising in the base area(c) areas enclosed by sections of the circuit (12), preferably by loop-shaped sections of the circuit,wherein said areas enclosed by sections of the circuit are equipped with turf and a robotic lawnmower (20) and optionally a related docking and charging station for said robotic lawnmower (20).7) The track for cycling and / or roller sports (10) according to any one of the previous claims, characterized in that the paving (28) further comprises a mixture of polymeric fibres, e.g., polyolefin fibres, and / or one or more structural meshes, in particular of basalt or glass.8) The track for cycling and / or roller sports (10) according to any one of the preceding claims, characterized in that the circuit (12) comprises a containment (24) below the subbase (26; 26a, 26b).9) The track for cycling and / or roller sports (10) according to any one of the preceding claims, characterized in that said aggregate has a regular particle size distribution of the “stabilized aggregate” type in fraction 0 / 20 - 0 / 30, a plasticity index PI < 6, a 0.063 mm sieve passing fraction < 10%, and a Los Angeles LA abrasion loss < 30.(10) A process for the construction of a track for cycling and / or roller sports (10) comprising the following steps:(I) preparation of a stabilized subbase (26; 26a, 26b) reflecting the layout of a desired circuit (28), which is preferably obtained by making a base stabilised subbase in which the conformation of the desired circuit (12) is excavated,(II) mixing of- a stabilizer adapted to increase the binding force between aggregate and hydraulic binder, in particular a stabilizer including at least one element selected from the group consisting of silicates, carbonates and phosphates and optionally aluminates, preferably a stabilizer comprising silicates, carbonates and phosphates,- of a desired amount of water,- of a hydraulic binder and- of an aggregate to obtain a paving mixture,(III) creating on said stabilized subbase (26; 26a, 26b) with the paving mixture obtained at the end of phase (II) a paving (28) above said subbase (26; 26a, 26b),wherein said paving (28) is advantageously constructed of multiple layers that are compacted individually or in groups as certain thicknesses are achieved.11) The process according to claim 10, characterized in that the ratios between stabilizer and hydraulic binder to be introduced in 1 m3of aggregate and the amount of water to prepare the paving mixture are optimized by determining at least one of the following parameters and / or carrying out at least one of the following tests:- particle size analysis;- the Atterberg consistency limit to determine plasticity;- a compaction or tamping test at varying water content to determine the maximum dry density and optimum moisture content for improved compaction;- the California Bearing Ratio (CBR) and / or tests for determining compressive strength and / or indirect tensile strength, preferably at 7 and / or 28 days.12) The process according to claim 10 or 11, characterized in that step (I) of the preparation of the subbase comprises the following steps:(1-1) in the circuit area application, preferably on a containment, such as a non-woven fabric, of one or more layers of the subbase material;(1-2) compacting the resulting structure when a desired thickness has been reached; (1-3) repeating steps (1-1) and (1-2) until the desired overall thickness of the subbase is obtained; and(1-4) excavation of the desired shapes of the circuit in the base subbase thus raised.

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