FR2987045A1 - Asphalt concrete composition, used to produce pavement upper layers, comprises a granular mixture of classic aggregates, corrective aggregates and hydrocarbon binder, where granular mixture have specific dimensions - Google Patents

Abstract

Asphalt concrete composition comprises a granular mixture of classic aggregates, corrective aggregates and at least one hydrocarbon binder, where the granular mixture satisfies the conditions including: 80-100 wt.% of the granular mixture components have dimensions of less than 6.3 mm; 60-100 wt.% of the granular mixture components have dimensions of less than 4 mm; 10-40 wt.% of the granular mixture components have dimensions of less than 2 mm; and 5-15 wt.% of the granular mixture components have dimensions of less than 0.063 mm, and the amount of corrective aggregates is 5-50 wt.%. Asphalt concrete composition comprises a granular mixture of classic aggregates, corrective aggregates and at least one hydrocarbon binder, where the granular mixture satisfies the conditions including: 80-100 wt.% of the granular mixture components have dimensions of less than 6.3 mm; 60-100 wt.% of the granular mixture components have dimensions of less than 4 mm; 10-40 wt.% of the granular mixture components have dimensions of less than 2 mm; and 5-15 wt.% of the granular mixture components have dimensions of less than 0.063 mm, the corrective aggregates satisfies the condition, 75-100 wt.% of corrective aggregates have dimensions of less than 4 mm and 0-2 wt.% of the corrective aggregates have dimensions of less than 2 mm, and the corrective aggregates have intrinsic characteristics including: accelerated polishing coefficient measured by standard NF EN 1097-8 is greater than 65; Los Angeles coefficient measured by standard NF EN 1097-2 is 15-35; and micro-Deval coefficient in presence of water measured by standard NF EN 1097-1 is 15-35, and the amount of the corrective aggregates is 5-50 wt.%. An independent claim is included for pavement upper layers having high adhesion properties comprising the composition.

Description

The present invention relates to asphalt concrete compositions positioned as a surface layer of pavements having exceptionally high and durable adhesion and to a process for their preparation. The traction capacity of the wearing course of a taxiway is an important parameter that depends among other things on weather conditions and changes over time as a result of changes in the macrotexture of the coating and the polishing of road surfaces. aggregates of the wearing course under the effects of traffic and / or climatic cycles and, in particular, variations in temperature. The adhesion requirements are variable depending on the profile of the road, turning zone or devers for example, depending on the presence of singular points, crossroads or lights for example, or, again, depending on other parameters such as the speed of circulation. It is therefore necessary to have materials, products or processes for obtaining a wearing course with the desired adhesion properties, constant over time. The wearing courses are generally made from aggregates (sands and gravel) of defined granular classes, optionally combined with mineral fines, the whole being bound by a generally bituminous binder to form a stable mix. The size ranges and shapes of the aggregates, and any mineral fines, determine the texture of the wearing course. The texture of the wearing course therefore depends on the size of the aggregates and fines present. There are three classes of textures, microtexture, macrotexture and megatexture. The respective effects of the first two texture classes on the adhesion parameters are complementary. In fact, the macrotexture in a wearing course acts on the adhesion by favoring the superficial drainage of the water. The micro texture, intrinsically linked to the petrographic nature of the rock from which the aggregate is extracted, influences the quality of the effective contact between the tire and the pavement by piercing the film of water still present on the pavement. Polishing causes gradual erasure of the microtexture. A high and durable microtexture makes the granulate less sensitive to polishing and thus ensures the durability of the adherent properties of the coating. The polishing resistance of the wearing course materials is evaluated by standardized tests known as PSV (Polished Stone Value) formerly known as CPA (accelerated polishing coefficient). One solution to this problem has been to use natural aggregates with different characteristics of hardness and polishing resistance (PSV). One solution is to use in the granular mixture calcined bauxite is an artificial granulate. However, bauxite has become economically and technically unattractive, especially in view of its constantly increasing price, the usual proportions needed, the constantly declining quality, availability and random sources ... There is a need to develop new compositions of bituminous concretes having a high adhesion and not having the disadvantages of the compositions of the prior art.

The applicant has found, surprisingly, that the use of a granular mixture comprising a particular and novel particle size distribution for this area of application combined with the use of corrector granules with characteristics different from those of calcined Bauxite makes it possible to obtain high adhesion performance.

Thus, the present invention aims at a composition of bituminous concrete for surface layers of pavements whose granularity and the composition of the granular mixture has been modified so as to improve the adhesion properties. This composition, when it is intended for the preparation of a wearing course, leads to a layer whose overall performance or characteristics usually expected for an asphalt concrete or coated with a wearing course is checked, namely: good mechanical strength under most traffic, - surface characteristics leading to very high adhesion properties between the tires and the road surface, especially in wet weather, - a homogeneous aesthetic appearance leading to unparalleled comfort for the user - ease of implementation, both in terms of manufacturing and application. The above aims are achieved by a composition of bituminous concrete comprising a granular mixture based on conventional aggregates and correcting aggregates and at least one hydrocarbon-based binder, characterized in that: a) the granular mixture satisfies the following conditions: at 100% by weight of the constituents of the granular mixture have dimensions less than 6.3 mm, - 60 to 100% by weight of the constituents of the granular mixture have dimensions less than 4 mm, - 10 to 40% by weight of the constituents of the granular mixture have dimensions less than 2 mm, - 5 to 15% by weight, preferably 7 to 10% by weight of the constituents of the granular mixture have dimensions less than 0.063 mm, b) the corrugated aggregates satisfy the following conditions: 75 to 100% by weight of the corrector granules have dimensions of less than 4 mm, - 0 to 20% by weight of the corrective aggregates have dimensions of less than 2 mm, ference, 0 to 2% by mass corrective aggregates have dimensions smaller than 0,063mm. c) the corrective aggregates have the following intrinsic characteristics: the accelerated polishing coefficient PSV measured according to the standard NF EN 1097-8 is greater than 65, preferably between 65 and 85, better than 68 and even better between 70 and 85, the Los Angeles coefficient measured according to the NF EN 1097-2 standard is between 15 and 35, preferably between 20 and 30 and better still strictly greater than 20, the micro-Deval coefficient in the presence of water measured according to the NF EN 1097-1 standard is between 15 and 35, preferably between 20 and 30 and better strictly greater than 20, d) the corrective aggregates represent 5 to 50% by weight, preferably 15 to 40% and better still 35% by weight of the granular mixture. The most often hydrocarbon binder may also be based on vegetable raw materials and / or synthesis. Preferably, the corrective aggregates also have an "Aggregate Abrasion Value" (AAV) coefficient measured according to the NF EN 1097-8 standard of less than 12.

As a general rule, a compromise must therefore be found between microtexture and macrotexture. It is difficult to obtain both durable polishing resistance and good adhesion. Surprisingly, the combination of the conventional and corrective aggregates used according to the invention coupled to a particular particle size distribution makes it possible to obtain excellent results in terms of adhesion and in particular to retain high values of accelerated polishing coefficient over time. (PSV) translating a conservation in time of microtexture. Unlike calcined bauxite aggregates, the corrector granulates used according to the invention do not exhibit exceptionally high hardness. Consequently, the maintenance of the microtexture can not be attributed to a non-wear of the corrective aggregates. Indeed, these aggregates have a hardness such that there is necessarily superficial removal (on a micrometric scale) of material. The maintenance of the microtexture properties of the mixture corresponds to a renewal or a permanent regeneration of the surface state. The solution of the invention uses a granular mixture preferably having a granularity 0 / 4mm and a specific granulometric curve modified to incorporate a better shear strength, the use of corrective aggregates having a high PSV and having both a contrast of hardness and PSV with conventional aggregates. The solution of the invention allows to develop a new versatile product and very high-end by its performance at a lower cost. The composition of bituminous concrete presents in particular a fine and harmonious texture (0 / 4mm) as well as a unique adhesion in the short and long term. Other characteristics, aspects and advantages of the invention will emerge even more clearly on reading the detailed description which will follow, as well as concrete, but in no way limiting, examples intended to illustrate it. The composition for upper layers of pavements has the following characteristics which can be taken individually or in all their technically possible combinations and each having specific advantages: the granular mixture satisfies at least one of the following conditions: 90 to 100%, preferably 100 to 100%; % by weight of the constituents of the granular mixture have dimensions less than 6.3 mm, 70 to 100%, preferably 80 to 100% and better still 90 to 100% by weight of the constituents of the granular mixture have dimensions less than 4 mm, - 20 to 40%, preferably 30 to 40% and more preferably 35 to 45% by weight of the constituents of the granular mixture have dimensions less than 2 mm, - 10 to 30 ° A, preferably 20 to 30% by weight of the constituents of the granular mixture have dimensions less than 1 mm, - 5 to 30%, preferably 10 to 20% by weight of the constituents of the granular mixture have dimensions less than 0.5 mm - 5 to 10%, preferably 7 to 10% by weight of the constituents of the granular mixture have dimensions less than 0.063 mm. the corrective aggregates have a real density of between 2500 and 3200 kg / 3, preferably of between 2600 and 2800 kg / m 3, measured according to standard NF EN 1097-6; conventional granulates have a real density between 2600 and 3000 kg / m3 measured according to standard NF EN 1097-6, - conventional aggregates have the following intrinsic characteristics: the accelerated polishing coefficient (PSV) measured according to standard NF EN 1097-8 is usually between 50 and 60 or strictly less than 60, the Los Angeles coefficient (LA) measured according to the standard NF EN 1097-2 is between 0 and 25, preferably between 0 and 20 or less than 20 and better still between 5 and 15, the micro-Deval coefficient (MDE) in the presence of water measured according to the standard NF EN 1097-1 is between 0 and 25, preferably between 0 and 20 and better still between 5 and 15 or less than 15, hydrocarbon binder is selected from a bitum Pure polymer modified bitumen such as an elastomer, for example from the SBS family, a binder of vegetable origin or a binder of a purely synthetic nature, pure bitumen or polymer-modified bitumen may comprise a additive allowing a lowering of the interfacial tension binding / aggregates and thus leading to a change in the viscosity allowing a decrease in its temperature of use such as fatty amines or any other compound or process resulting in this property, the hydrocarbon binder is a pure bitumen or a bitumen modified with a polymer introduced in the form of bitumen foam or bitumen emulsion, the residual proportion of hydrocarbon-based binder is between 5 and 7%, preferably between 5.2 and 6.2. %, - the binder is in anhydrous form, fluxed, or in the form of foam or emulsion, - the granular mixture can also satisfy the following conditions in mass with respect to the total mass of granular mixture: 5 to 50% by weight of the constituents of the granular mixture are correcting aggregates 2/4, 20 to 45% by weight of the constituents of the granular mixture are conventional aggregates 2/4, 20 to 40% by weight mass of the constituents of the granular mixture are 0/2 conventional granulates. the percentage of geometric vacuum according to the gyratory shear press test (PCG) according to standard NF EN 1269-31 at 25 girations is generally between 10 and 20 °. The subject of the present invention is also a process for preparing the composition for surface-course layers defined above, the use of such a composition for the production of road surface layers having high adhesion properties. and a pavement surface layer based on such a composition. The invention also relates to a pavement comprising a wearing course comprising a composition for pavement surface layers according to the invention. The residual proportion of binder corresponds to the mass of hydrocarbon binder expressed as a percentage, relative to the total mass of the aggregates and the hydrocarbon binder (does not include fluxing agents or constituents other than emulsions). For the purpose of the present description, "granularity" is understood to mean the dimensional distribution of the grains of a granular mixture, expressed as a mass percentage of material passing through a specified set of sieves. By "passing" is meant the fraction of a granular mixture passing through the smaller sieve used in the designation of a granular class. These definitions correspond to those of standards NF P18-545 and EN 13043. Passers-by are obtained during the test of determination of the granularity by size analysis by sieving according to the standard EN 933-1. A granular class, denoted d / D with d <D, denotes a particle size range in terms of the lower (d) and upper (D) sieve dimensions, expressed in mm. The size of a particle, and more generally of a constituent of a granular mixture, corresponds to its diameter if this constituent is of spherical shape. If the component does not have a spherical shape, its dimension corresponds to the length of its primary axis, that is to say the longest straight line that can be drawn between an end of this component and an opposite end. It can be characterized by sieving. The composition for surface layers of pavements according to the invention comprises at least one binder and a granular mixture satisfying the aforementioned conditions. Corrective aggregates are natural or artificial aggregates, preferably natural ones.

According to the invention, the term "conventional" granulate represents a granulate other than a corrective granulate and meeting the requirements of a road use. These aggregates are preferably derived from the crushing of massive rocks or alluvial rocks. The so-called "conventional" aggregates used according to the invention generally have the following intrinsic characteristics: PSV between 50 and 56, MDE between 0 and 20, LA between 0 and 25. The so-called "conventional" granulates used. according to the invention may be chosen according to their granular composition. Conventional aggregates therefore refer to a granular material used in construction. A granulate can be natural, artificial or recycled. The term "natural granulate" means a granulate that has not undergone any deformation other than mechanical. The term "artificial granulate" refers to a granulate of mineral origin resulting from an industrial process comprising thermal or other transformations. The term "recycled granulate" refers to a granulate obtained by treatment of an inorganic material previously used in the construction. The aggregates used are road aggregates, meeting the relevant standards: NF EN 13043 in Europe and ASTM C33 in the United States of America. The granular classes (d / D) of the constituents of these mixes that are the subject of the series of French product standards EN 13 108-1 and -2 that can be used according to the invention are the following: 0/2, 0/4 , 2/4, 0/5, 0 / 6,3, 2/5, 2 / 6,3 and 4 / 6,3. These granular classes have the same meaning as in standard NF P18-545. The conventional aggregates present in a composition according to the invention may be, without limitation, fillers, fines, sand, sand, gravel, chippings, gravels, crushed stones, dust, filler. The term "filler" means particles of which at least 70% by mass are smaller than 0.063 mm.

The hydrocarbon binder used in the present invention provides a bonding between the various constituents of the granular mixture by solidifying immediately after the end of implementation of the upper layer of pavement, wherein it partially or completely covers said constituents. It can optionally be used to stick the constituents of the granular mixture on the support on which they are spread. Since the adhesion properties derive mainly from the granularity and the particular composition of the granular mixture, the hydrocarbon binders usable in the invention can be of very diverse natures. According to a first embodiment of the invention, the binder is a "bituminous binder" which designates a bituminous compound chosen from pure, modified special bitumens or their mixtures, and capable of hardening and bonding granular materials to each other. The bituminous binder according to the invention is generally a mixture of natural hydrocarbonaceous materials derived from the heavy fraction obtained during the distillation of petroleum, or coming from natural deposits in solid or liquid form, with a density generally of between 0.8 and 1.2. It can be prepared by any conventional technique.

For example, bituminous binders within the meaning of the invention are acceptable for the pure bitumens defined in standard NF EN 12591, such as bitumens of class 160/220, 100/150, 70/100, 50/70, 40/60, 35 / 50, 30/45 or 20/30, without limitation. These standard classes correspond to ranges of penetrability at 25 ° C determined according to the method EN 1426 and are expressed in 1 / 10th of a mm.

More advantageously, the bituminous binders are modified bitumens defined in standard NF 14023, for example modified bitumens by incorporating additives of any kind such as additives for the purpose of improving the adhesiveness characteristics or the mechanical strength under traffic. high or aggressive, or to artificially provide the properties necessary for cationic emulsification. Mention may be made of bitumens improved by incorporating organic or mineral fibers, in particular glass, carbon or cellulose fibers, by incorporation of synthetic or natural elastomers of the rubber powder (polybutadiene, styrene-butadiene rubber or SBR) type, copolymers of ethylene and vinyl acetate (EVA), random or block copolymers of styrene and conjugated dienes, for example SBS block copolymers, by incorporation of thermoplastics such as, for example, polyolefins (polyethylene, polypropylene), polyamides and polyesters, or by incorporation of thermosetting resins such as epoxy resins (bitumen / epoxy binders) or polyurethane resins. This list is of course not limiting. It is also possible to use mixtures of bitumens of different types.

According to another embodiment of the invention, the binder may be of plant origin. It can be a natural resin or a resin of vegetable origin modified by synthesis. This category of binder is interesting because of agro-resources that are by definition renewable. By way of example, mention may be made of the binders described in patent application FR 2853647, such as Vegecol® or Vegeclair® marketed by the Colas Group.

According to a third embodiment of the invention, the binder is a binder of a purely synthetic nature. Generally, such a synthetic binder is of organic nature, preferably of polymeric nature. It may be formed of a thermoplastic material, elastomer or a thermosetting material, that is to say curable, or a mixture of one or more of these materials.

Of course, the composition according to the invention may comprise mixtures of binders belonging to the various categories mentioned, that is to say that it comprises at least one binder chosen from bituminous binders, binders of plant origin and binders of a purely synthetic nature. The binders used in the invention may include additives such as metal salt curing catalysts, and / or one or more coloring agents such as inorganic pigments or organic dyes. The binders presented above may also be fluxed by a fluxing agent or fluidizer intended to lower their viscosity, for example a solvent-based fluxing agent of petroleum or petrochemical origin or a fluxing agent based on naturally occurring fats. These binders may optionally contain from 0.5 to 35% flux, preferably from 0.5 to 10% by weight relative to the total mass of binder. These binders may be in anhydrous form or in emulsion form according in particular to NF EN 13808, or a mixture of both. When the binder is used as an emulsion, the binder / water affinity depends on the interfacial tension between these two products. This affinity can be improved by means of an anionic, cationic, zwitterionic or nonionic surfactant, such as, for example, a fatty amine hydrochloride, a fatty acid salt, a quaternary ammonium salt or a polyoxyethylene oxide. ethylene or mixtures thereof. Preferably, the granular mixture and the binder (s) is (are) used in amounts such that the richness modulus of the composition, as defined in standard NF P98-149, is greater than or equal to equal to 3, preferably between 3.3 and 3.7. The invention also relates to a process for preparing a composition for surface layers of pavements having high adhesion properties comprising a step of mixing the binder (or binders) and the granular mixture defined above. The method preferably comprises a step of total or partial coating of the granular mixture with the binder (or the binders). The coating may be carried out hot or cold, in accordance with standard NF P98-150, delivering so-called hot mix or cold. During the preparation of a cold mix, the binder can advantageously be emulsified and the corresponding technique is called the coating emulsion. It should be noted that the coating can also be performed at so-called warm or semi-warm temperature.

The process for preparing the pavement surface layer composition according to the invention may be a hot preparation process, comprising a step of mixing said binder and said granular mixture at a temperature of 130 to 190 ° C. According to another embodiment, the process for preparing the composition for pavement surface layers according to the invention may comprise a step of mixing said binder and said granular mixture at a temperature of 100 and 150 ° C. low temperature -). Surprisingly the mixture of aggregates does not pose any particular problem during the realization of asphalt concrete or its implementation. In fact, contrary to what might have been expected from mixing materials of different origins and densities within the fluid medium that is the bituminous binder, there is no segregation between the aggregates. There is no sedimentation or flotation phenomenon. Another object of the invention is the use of a composition as defined above for the production of upper layers of pavements having high adhesion properties.

The pavement surface layer compositions of the present invention allow in particular the preparation of wearing courses as defined in the technical guide Design and Dimensioning of Road Structures of SETRA / LCPC of 1994, the NF P 98-086 standard of October 2011 and the NF P98-150 standard for hydrocarbon mixes.

Thus, in the case of a wearing course, the layer of materials in direct contact with the tires of the vehicles is meant. Another object of the present invention is an upper road layer with high adhesion properties based on at least one composition for upper layers of roadways as defined above. The compositions of the invention make it possible to produce wearing courses which have a high and durable adhesion over time because these layers are resistant to polishing as well as to mechanical and climatic stresses. The upper layer of pavement has a compacted thickness of less than or equal to 70 mm, more preferably from 15 to 45 mm and even more preferably from 20 to 30 mm.

The upper pavement layer of the invention may be applied to new or old supports made of a material bound with a hydrocarbon binder or with a hydraulic binder. The particular granularity of the compositions of the invention leads, for application thicknesses as described above, to upper layers of pavements having a void percentage preferably between 10 and 20% to 25 girations in the sense of the standard. EN 12697-31 (PCG test). The pavement top layer of the invention preferably has a void percentage of from 15 to 25% at 25 girs according to EN 12697-31 (PCG test). The improvement of the adhesion properties related to the setting The use of a composition for upper layers of pavements according to the invention is obtained without reduction of the other mechanical properties. The upper road layer defined above can be prepared according to a coating technique, that is to say using a composition according to the invention prepared by contacting the binders with the granular mixture before application to the concerned support. The support on which the layer of the invention is deposited may possibly have undergone a known preparation step. Various features and advantages of the present invention will become apparent from the illustrative examples set forth below.

Examples I. Materials used 1. Aggregates The conventional aggregates used have the following intrinsic characteristics (NF P 18-545 standard): - P.S.V. between 50 and 56 - L.A .: 20 * - M.D.E. : 15 * * with maximum compensation (defined by standard NF P 18-545) of 5 points between LA and MDE. The corrective aggregates have the following characteristics: - Abrasion resistance test: AAV 15 (NF EN 1097-8 - Annex A) - Dry density: 2.5 to 3.0, (NF EN 1097-6) - PSV : 65 - L.A .: 15 LA 35 - M.D.E. : MDE 35 P.S.V. : Accelerated Polishing Stone (PSV), which translates polishing / polishing resistance, measured according to standard NF EN 1097-8, LA: Los Angeles coefficient of impact resistance, measured via the Los test. Angeles defined according to standard NF EN 1097-2, MDE : Micro Deval coefficient in water showing the resistance to wear in the presence of water, measured via the Micro Deval Wet test defined according to standard NF EN 1097-1. The table below gives the granulometric distribution of aggregates used. Aggregates Sand 0 / d Granulate d / D Filler Sand 0/4 Nature of aggregates classical classic classic correctors 6.3 100 100 100 100 4 100 80-100 100 75-100 2 80-100 0-20 100 0-20 1 - - 100 - 0,5 - - 100 - 0,25 - - 100 - 0,125 - - 100 - 0,063 10 - 20 0 - 1 70 - 100 <2 Density NF EN 1097-6 2600 to 3000 2600 to 3000 - 2600 to 2800 2. Hydrocarbon binder The hydrocarbon binder used is Sacerflex® E3 modified bitumen. SACERFLEX® is a polymer bitumen modified with a variable proportion of polystyrene-polybutadiene-polystyrene thermoplastic elastomer and chemical additives. Its real density is 1020 kg / m3. II. Composition and preparation of the mixes The mixes are prepared according to standard NF EN 12697-35 in a kneader at a temperature of 160 to 185 ° C for 240 s. The compositions described in the table below were recomposed and then manufactured in a hot-mix plant. The composition is defined in% by weight relative to the total mass of the asphalt composition.

Components Composition of the invention Filler 3 cyo Sable 0 / d 25% Chippings (granulate d / D) 36.4 (3/0 2/4 corrector 30 (3/0 Binder 5.6% Granulometric distribution (Sieve) Composition the invention 6.3 0.313 0.250 14 0.063 8% by weight of the corrective granules with: D <6.3 100% D <4 75% to 100% D <20 to 20 % by weight of correcting granules with respect to the mass of the granular mixture II Evaluation of the behavior of the coating under the effects of the circulation In situ tests have shown that a wearing course made from a composition according to the The invention makes it possible to maintain the adhesion at a high level (CFT> 70) at 6 months (the time required for stripping the binder film covering the granulate) against 60 or even 65 for a conventional coating III.Laboratory comparative studies The new coating was tested in the laboratory using Wehner & Schulze WS (NF EN 12697-49) and compared to various other coatings. Prior art adhesives of the state of the prior art: Type of coating Granularity Correcting gravel in the mix (in%) (in mm) Of the invention Bauxite BBTM adherent of the invention 0/4 30 0 BBTM control 1 (comparative) 0/10 0 0 BBTM Bauxite 1 (comparative) 0/10 0 20 BBTM Bauxite 2 (comparative) 0/10 0 34 BBTM adherent (comparative) 0/10 71 0 BBTM control 2 (comparative) 0/10 0 0 PSV coating type: PSV correction gravel: conventional chippings WS Coating Factor (wArs) BBTM adherent of the invention 70 52 to 54 0.43 BBTM control 1 (comparative) - 50 to 52 0.34 BBTM Bauxite 1 (comparative ) 70 50 to 52 0.40 BBTM Bauxite 2 (comparative) 70 54 0.45 BBTM adherent (comparative) 63 to 66 50 to 52 0.45 BBTM control 2 (comparative) - 54 38 The WS coefficient values of the composition object of the invention are greater or of the same order as those of the state of the prior art. The "new" adherent BBTM composition is greater than: BBTM control 1, BBTM control 2, BBTM Bauxite 1. The adherent BBTM composition of the invention is of the same order as: BBTM Bauxite 2 (34% Bauxite) ) - BBTM adherent (71% of aggregates with high PSV> 60) In these two latter cases, the composition of the invention is economically more interesting, for almost identical effective performance.

Claims (10)

REVENDICATIONS1. Bituminous concrete composition comprising a granular mixture based on conventional aggregates and correcting aggregates and at least one hydrocarbon-based binder, characterized in that: a) the granular mixture satisfies the following conditions: 80 to 100% by weight of the constituents of the mixture granular materials have dimensions less than 6.3 mm, - 60 to 100% by weight of the constituents of the granular mixture have dimensions less than 4 mm, - 10 to 40% by weight of the constituents of the granular mixture have dimensions of less than 2 mm 5 to 15% by weight of the constituents of the granular mixture have dimensions of less than 0.063 mm; b) the corrective aggregates satisfy the following conditions: 75 to 100% by weight of the corrective aggregates have dimensions less than 4 mm; 0 to 20% by weight of corrective aggregates have dimensions less than 2 mm, c) corrector aggregates have the following intrinsic characteristics: tes: the accelerated polishing coefficient measured according to the NF EN 1097-8 standard is greater than 65, the Los Angeles coefficient measured according to the NF EN 1097-2 standard is between 15 and 35, the Deval micro-coefficient in the presence of water measured according to the standard NF EN 1097-1 is between 15 and 35, d) the corrective aggregates represent 5 to 50% by weight of the granular mixture. 2. Composition according to claim 1, characterized in that the granular mixture satisfies at least one of the following conditions: 100% by weight of the constituents of the granular mixture have dimensions less than 6.3 mm, 70 to 100% by weight constituents of the granular mixture have dimensions less than 4 mm, - 20 to 40% by weight of the constituents of the granular mixture have dimensions less than 2 mm, and / or - 7 to 10% by weight of the constituents of the granular mixture have dimensions less than 0.063 mm. 3. Composition according to any one of the preceding claims, characterized in that the corrective aggregates further verify the following condition, 0 to 2% by weight of the corrective aggregates have dimensions less than 0.063mm. 4. Composition according to any one of the preceding claims, characterized in that the corrective aggregates have a real density of between 2500 and 3200 kg / m3. 5. Composition according to any one of the preceding claims, characterized in that the conventional aggregates have the following intrinsic characteristics: the accelerated polishing coefficient measured according to the standard NF EN 1097-8 is between 50 and 60, the coefficient of Los Angeles measured according to standard NF EN 1097-2 is between 0 and 25, the micro-Deval coefficient in the presence of water measured according to the standard NF EN 1097-1 is between 0 and 20. 6. Composition according to any one of the preceding claims, characterized in that the residual proportion of hydrocarbon binder is between 5.2 and 6.2%. 7. Composition according to any one of the preceding claims, characterized in that the hydrocarbon binder is a bitumen modified with an elastomer. 8. Use of a composition according to any one of claims 1 to 7 for the realization of upper layers of pavements having high adhesion properties. 9. Upper layer of pavement having high adhesion properties based on at least one composition according to any one of claims 1 to 7. 10. The upper road layer according to claim 9, having a compacted thickness less than or equal to 70 mm.