Process for manufacturing cold-mix asphalt and cold-mix asphalt with rapid cohesion buildup

Abstract

The present invention relates to a method for manufacturing a road surface layer based on cold-mix asphalt, comprising the following steps: a) coating at ambient temperature in a mixer of a self-propelled machine a mineral solid fraction with a cationic emulsion of hydrocarbon binder; water is introduced into the mixer at a concentration such that the total water content is between 8 ppt and 14 ppt relative to the weight of the dry solid mineral fraction to form a cold-mix asphalt in which the content of conventional residual anhydrous binder as described in standard NF P 98-139:2016-12 varies from 3.5 to 6%, relative to the weight of the asphalt after drying; b) applying the cold-mix asphalt directly from the mixer of the self-propelled machine to form a layer having a thickness of at least 2 cm.c) then compaction of the layer laid down in step b) to form the road surfacing layer.

Description

Title of the invention: METHOD FOR MANUFACTURING COLD HYDROCARBONATE COATINGS AND COLD-MOUNTED HYDROCARBON MIXES WITH RAPID COHESION BUILDING technical field

[0001] The present invention relates to the field of bituminous mixtures for road construction. More particularly, the present invention relates to the cold mixing of mineral solid fractions and a cationic emulsion of hydrocarbon binders directly on site using application machines equipped with an on-board mixer in order to produce cold bituminous mixtures with rapid cohesion build-up.

[0002] TECHNOLOGICAL BACKGROUND: Bituminous coatings

[0003] Among hydrocarbon coatings, two main families are distinguished: hot hydrocarbon coatings and cold hydrocarbon coatings.

[0004] Hot mix asphalt is obtained by hot mixing of aggregates and a hydrocarbon binder. The aggregates are heated, generally to a temperature above 100°C. This asphalt exhibits good coverage, good workability, and mechanical properties after application and cooling that meet the expectations of those skilled in the art. The cohesion of this asphalt develops rapidly and clearly, occurring within a few hours of the surface cooling.

[0005] Cold-mix asphalt is obtained by cold mixing of solid mineral particles, possibly moistened, with an emulsified hydrocarbon binder. The use of a cationic emulsion of the hydrocarbon binder allows for coating without drying or heating the solid mineral particles due to the low viscosity of the hydrocarbon binder emulsion at near-ambient temperature. The cold production of these asphalt mixes significantly reduces the energy consumption required for hot-mix asphalt to dry and heat the solid mineral particles. Cold-mix asphalt is therefore recognized for reducing the environmental footprint of hydrocarbon asphalt during the manufacturing stages.

[0006] Cold-mix asphalt and cold-applied bituminous materials

[0007] The cold-mix asphalts according to the invention have the properties of emulsion asphalts described in the guide Factory-made emulsion asphalts, Cerema, 2020 or in the old standards NF P 98-139:2016-12 and NF P 98-121:2014-10.

[0008] The characteristic mechanical properties of cold-mix asphalt include, in particular: - resistance to compression, water resistance, seen through a Duriez test (NF P 98-251-4: August 2004); - the compaction capability as seen through the gyratory shear press compaction test (NF P 98-252: June 1999); - the stiffness modulus (NF EN 12697-26 annex C, June 2018).

[0009] Cold-mix asphalt according to the invention is distinct from cold-applied bituminous materials. Cold-mix asphalt adheres to different formulation rules than cold-applied materials, and its application is also different. Finally, its mechanical performance is evaluated through different laboratory tests.

[0010] Cold-poured bituminous materials are described in the guide Cold-poured bituminous materials, Cerema or in the standard NF EN 12273 "MBCF: specifications" or the former standard NF P 98 150. Cold-poured bituminous materials have a residual binder content greater than 5.5 ppc (part percent by weight), relative to the weight of the dry solid mineral fraction.

[0011] The characteristic mechanical properties of cold-poured bituminous materials are: - setting or fluidity time: time determined as the duration between the start of mixing the constituents and the setting of the MBCF; - the breaking time: the time it takes for the emulsion in the MBCF to break completely; - the cohesion time: the time during which the cohesion of the MBCF is sufficient for opening to traffic; - resistance to wear (or abrasion): test carried out after a more or less long maturation period to ensure the durability of the MBCF under traffic.

[0012] Application FR 2 927 328 describes a process for manufacturing a cold-applied asphalt mix capable of being applied in a thick layer of at least 1.5 cm, said asphalt mix comprising the following constituents: - a hydrocarbon binder in the form of a cationic emulsion, - aggregates, - water for supply and, - at least one additive.

[0013] According to the invention, at least one of the additives comprises a synthetic, natural or modified natural gum, and this additive comprising a synthetic, natural or modified natural gum is added to the emulsion stream or to the supply water prior to mixing all of said constituents. However, application FR 2 927 328 refers to the field of cold-mix asphalt as defined by standard NF P 98 150. Application FR 2 927 328 does not at any point describe a process for preparing a cold-mix asphalt as defined in standards NF P 98-139:2016-12 and NF P 98-121:2014-10. Cold-mix asphalt

[0014] The binder used for manufacturing hydrocarbon binder emulsions is bitumen, polymer-modified bitumen, a petroleum-based synthetic binder, and / or a vegetable-based binder. The binder may be fluxed or fluidized by petroleum- or vegetable-based products.

[0015] When a cationic bitumen emulsion is used as a binder, the resulting cold-mix asphalts are divided into two categories of products: - emulsion-aggregates (GE) for base courses, binder courses and reprofiling; - emulsion-based bituminous concretes (BBE) for wearing courses.

[0016] The manufacturing temperature of cold-mix asphalt, which is close to ambient temperature (the recommended minimum temperature is approximately 10°C, so the advantageous range is from 10°C to 40°C), gives the binder, after the emulsion breaks down, a very important role in the workability and compactability of the asphalt. Within this temperature range, the high viscosity of the binder reduces the compactability of the asphalt and thus diminishes the mechanical properties of the resulting asphalt mix.

[0017] Cold mix asphalt overcomes many of the constraints associated with hot mix asphalt. However, cold mix asphalt has some drawbacks and technical limitations.

[0018] First, the reactivity of the hydrocarbon binder emulsion with mineral solid particles sometimes leads to poor coating quality, particularly when the mineral solid particles have a high fines content. Indeed, the more fines the granular fraction contains, the worse the distribution of the binder will be on the granular fraction (mainly on the larger particles). Furthermore, this coating defect can be exacerbated by the numerous handling operations of the asphalt mix (transport, passage through the screw conveyors of the paver, compaction), which lead to coating stripping problems due to abrasion of the binder film on the granular surfaces. These coating problems cannot be improved by increasing the water content of the mix because cold mix asphalts are very sensitive to the total water content of the mix, which generates workability problems when the water content is too high.

[0019] Workability is also an inherent technical limitation of cold mix asphalt. During the transport time of the asphalt between the mixing plant and the construction site, cohesion builds up following the rupture of the emulsion upon contact with the solid mineral particles. This cohesion build-up is generally slowed down by several means, including reducing the binder content of the asphalt, using fluxing agents, or using very slow-breaking surfactants. These actions have a positive effect on the affect the handling of the asphalt during transport but also have a detrimental effect on the recovery of the cohesion of the asphalt when it has been applied to the road surface.

[0020] To remedy or limit problems of poor distribution of the bitumen film over the entire granular fraction, the mixing step of the granular fractions and the emulsion binder can be sequenced. Indeed, while emulsion-treated aggregates and cold-mix asphalt for subgrades or resurfacing are normally manufactured by simple coating, emulsion-treated asphalt concrete (EAAC) and cold-mix asphalt for wearing courses generally use sequenced coating due to the need to obtain very good coverage for these surface coatings. Sequencing methods are described in patents EP 0 384 094, EP 0 524 031, EP 0 781 887 and FR 2 960 890.

[0021] In order to improve the behavior of cold mix asphalt, in particular with regard to coating, workability and cohesion building, various processes including a heating step have been proposed, in particular in patents EP 0 552 574, FR 2 732 239 and EP 1 668 184.

[0022] The technological background demonstrates the benefit of certain processes for improving the performance of cold-mix asphalt. Properties such as coating, workability, and cohesion recovery can thus be optimized by sequencing the addition of mineral solids and binder, or by means of a heating step.

[0023] A need remains for the development of new solutions to significantly increase the cohesion of cold-mix asphalt, particularly for wearing courses, while ensuring good coating of the asphalt. This is to improve the early-age shear strength of cold-mix asphalt and thus allow for wider use of these pavements, especially for the heaviest traffic areas.

[0024] The aim of the present invention is therefore to overcome the technical limitations mentioned above, and to propose a method for manufacturing a cold-mix asphalt that allows: - to eliminate the need for sequencing to obtain good coating of the asphalt, regardless of the petrographic nature of the solid mineral particles; - to eliminate the numerous handling problems associated with the production of cold-mix asphalt in a plant; - to avoid the use of fluxing agents which improve workability and compactability but inhibit the rapid rise in cohesion of cold-mix asphalt; - to control the coalescence of the hydrocarbon binder emulsion; - to improve the cohesion of cold-mix asphalt without a heating process; - to increase the short, medium and long term mechanical resistance of cold-mix asphalt.

[0025] To this end, the applicant discovered that the in-situ production of cold asphalt on-site using a self-propelled machine equipped with a mixer would make it possible to achieve the aforementioned objectives and resolve the problems of the prior art. The applicant also discovered that, despite the small size of the mixer on a self-propelled machine, it is possible to meet the coating requirements of cold asphalt by adapting a water content that is unusually high for cold asphalt.

[0026] A self-propelled machine makes it possible to meet coating expectations without specific sequencing of materials and with very different mixer geometries.

[0027] The applicant has discovered that the formulations according to the invention make it possible to prepare cold-mix asphalt that can be manufactured in situ and thus make it possible to circumvent the problems related to transport.

[0028] BRIEF DESCRIPTION OF THE INVENTION:

[0029] The invention relates to a method for manufacturing a road surface layer based on cold-mix asphalt, comprising the following steps: a- coating at ambient temperature in a mixer of a self-propelled machine a mineral solid fraction with a cationic emulsion of hydrocarbon binder, water is introduced into the mixer in such a content that the total water is between 8 ppc and 14 ppc relative to the weight of the dry solid mineral fraction to form a cold-mix asphalt in which the content of conventional residual anhydrous binder as described in standard NF P 98-139:2016-12 varies from 3.5 to 6%, relative to the weight of the asphalt after drying b- implementation of the cold-mix asphalt directly from the outlet of the mixer of the self-propelled machine to form a layer having a thickness of at least 2 cm; c- then compaction of the layer implemented during step b) to form the road surfacing layer.

[0030] Advantageously, the hydrocarbon binder cationic emulsion comprises as an emulsifier at least one amine, the amine representing at least 50% by weight of the total weight of the emulsifiers.

[0031] In particular, the amine is chosen from: - alkylpolyamines, including alkyl diamines; - fatty amines; - amidopolyamines; - quaternary ammonium compounds with fatty chains; - and their combinations.

[0032] In a preferred embodiment, the hydrocarbon binder cationic emulsion comprises, as emulsifiers: (1) at least one alkylpolyamine, comprising one or two radicals selected from a saturated or unsaturated hydrocarbon residue comprising 8 to 24 carbon atoms and / or its immediate cyclization derivatives as well as its oxyethylated or oxypropylated derivatives; and (2) at least one amidopolyamine of formula (IV) Ri'CO-(NH-Ri”)a-NH2, R / being a hydrocarbon remainder, saturated or unsaturated, comprising from 12 to 24 carbon atoms, Ri” an ethylene radical, has an integer from 2 to 5 and / or its immediate cyclization derivatives; the cationic emulsion comprises a mineral acid chosen from phosphoric acid or a polyphosphoric acid; and the binder includes a fatty acid dope or fatty acid derivative.

[0033] Cold-mix asphalt is advantageously chosen from emulsion-aggregates or emulsion-based bituminous concretes.

[0034] The mineral solid fraction advantageously meets one or more of the following characteristics: - the passing at 0.063 mm of the solid mineral fraction varies from 4% to 10% by weight, relative to the weight of the dry solid mineral fraction; - the 16 mm passing of the solid mineral fraction is 100% by weight, relative to the weight of the dry solid mineral fraction; - the 2 mm passing of the solid mineral fraction varies from 30% to 50% by weight, relative to the weight of the dry solid mineral fraction; - the 2 mm passing of the solid mineral fraction varies from 20% to 40% by weight, relative to the weight of the dry solid mineral fraction.

[0035] The mineral solid fraction advantageously constitutes 94% to 96.5% by weight, advantageously 94% to 95.5% by weight, of the weight of the asphalt.

[0036] Advantageously, the coating does not contain gum.

[0037] In the process, during step a), water is introduced into the mixer in such a quantity that the total water is advantageously between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction.

[0038] The process may include a step prior to step a) of humidifying the mineral solid fraction.

[0039] The road surface layer is advantageously chosen from a wearing course having a thickness varying from 1.5 cm to 3 cm, a wearing course having a thickness varying from 3 cm to 5 cm, a wearing course having a thickness varying from 5 cm to 8 cm, a base course, a resurfacing or a reprofiling.

[0040] The self-propelled machine advantageously comprises, in addition to the mixer: - a feed hopper for solid mineral particles; - an emulsion tank; - a smoothing sled or a finishing sled; - a water tank; - optionally a hopper for powdered materials, such as lime or cement, and / or a lime slurry tank; - optionally a fiber dosing system. Description of the implementation methods

[0041] It has been shown that the manufacture and implementation of a cold-mix asphalt using a self-propelled machine equipped with a mixer makes it possible to obtain a road surfacing product with good coating, fluidity and handling adapted to manufacture in a specific self-propelled machine and a rise in cohesion allowing for a rapid return to traffic, in particular in less than one hour, more advantageously in less than 30 minutes.

[0042] Cold-mix asphalt obtained by this process exhibits good coating quality (at least equivalent to that observed for hot-mix asphalt) without the drawbacks observed with prior art processes, particularly those arising from their in-situ production and subsequent application. Adjusting the water content of the cationic emulsion of the hydrocarbon binder allows for regulation of the coating and rheology (fluidity) of the asphalt during application. The surfactants used ensure good coating, sufficient workability time, and rapid cohesion recovery. As described later, it may be advantageous to add a mineral additive such as cement or a calcium or calcium-magnesium slurry. Furthermore, no heating or reheating step is necessary to adjust the workability of the asphalt or to hydrophobicize a portion of the aggregates.The cold-mix asphalt obtained by the process according to the invention therefore meets the requirements of standard NF P 98-139:2016-12 or NF P 98-121:2014-10 and the energy consumption in fuel is low.

[0043] Thus, the invention relates to a method for manufacturing a road surfacing layer based on cold-mix asphalt, comprising the following steps: a- coating at ambient temperature in a mixer of a self-propelled machine a mineral solid fraction with a cationic emulsion of hydrocarbon binder, The mineral solid fraction constitutes the entire mineral solid fraction of the cold-mix asphalt water is introduced into the mixer at a concentration such that the total water is between 8 and 14 ppc relative to the weight of the dry solid mineral fraction to form a cold hydrocarbon mix in which the conventional residual anhydrous binder content as described in standard NF P 98-139:2016-12 varies from 3.5 to 6%, relative to the weight of the mix after drying; b- implementation of the cold hydrocarbon asphalt directly from the outlet of the self-propelled machine mixer to form a layer with a thickness of at least 2 cm; c- then compaction of the layer implemented during step b) to form the road surfacing layer.

[0044] The process is therefore characterized in that the bituminous mix is ​​prepared in a mixer directly on site, in situ. Unlike the bituminous mixes described in the aforementioned guide, the bituminous mix is ​​not pre-prepared at the factory. Step a) is therefore carried out on site.

[0045] The term “ambient temperature” defines a temperature ranging from 10°C to 40°C, preferably from 15°C to 35°C.

[0046] The terms "coating" and "hydrocarbon coating" are used interchangeably to refer to the cold hydrocarbon coating obtained following step a) of the process according to the invention.

[0047] The term "ppc" means part per cent by weight. Quantities are expressed relative to the weight of the dry solid mineral fraction. For binder content, standard NF P 98-139:2016-12 requires that the content of residual conventional anhydrous binder be stated, expressed as a percentage by weight relative to the weight of the asphalt mix after drying.

[0048] Once the process has been initiated, steps a, b and c are most often carried out simultaneously.

[0049] Advantageously, the process does not involve sequencing. Advantageously, the process does not involve pre-coating, in particular with sand and / or gravel.

[0050] Thus, advantageously, the mineral solid fraction added in step a) constitutes the entire mineral solid fraction of the cold-mix asphalt. Advantageously, the mineral solid fraction is not preheated, even partially.

[0051] Thus, advantageously, if a fluxing agent is added, its addition is not sequenced. Advantageously, no fluxing agent is added.

[0052] The total water in the composition of the cold-mix asphalt plays a determining role in regulating the rheology, fluidity and coating of the composition during manufacturing and implementation.

[0053] During step a), the total water content is advantageously between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction. Thus, advantageously during step a), water is introduced into the mixer at a concentration such that the total water content is between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction.

[0054] The coating comprises the following constituents: - a hydrocarbon binder in the form of a cationic emulsion; - a solid mineral fraction; - of the supply water; - possibly one or more additive(s).

[0055] Thus, in step a), a hydrocarbon binder in the form of a cationic emulsion, a mineral solid fraction, feed water, and optionally one or more additives are added to the mixer. These constituents are mixed in step a), the emulsion breaks down, and the hydrocarbon binder coats the mineral solid fraction to form a hydrocarbon coating. The process according to the invention provides good coating of the mineral solid fraction, including the largest particles.

[0056] The other constituents are then the constituents usually used. Advantageously, the bituminous mix does not contain synthetic, natural, or modified natural gum. In particular, the mix prepared in step a) is advantageously chosen from emulsion-treated aggregates or emulsion-treated bituminous concretes. The mix prepared in step a) thus advantageously meets the definitions of standards NF P 98-139:2016-12 or NF P 98-121:2014-10. Hydrocarbon binder:

[0057] The term "binder" means any hydrocarbon binder of fossil or vegetable origin usable for the production of asphalt mixes, in particular pure bitumen or bitumen modified by the addition of polymer(s). Thus, the binder is advantageously a bitumen, including paraffinic or naphthenic bitumens, a bitumen modified by polymers, a petroleum-based synthetic binder and / or a vegetable binder.

[0058] The binder may be a soft to hard binder, advantageously of a grade ranging from 10 / 20 to 160 / 220. Advantageously, the binder is chosen from binders of grade equal to or greater than 50 / 70, more advantageously from binders of grade 50 / 70, 70 / 100, 100 / 150 or 160 / 220.

[0059] The binder may include additives commonly used in road construction, such as crosslinked or non-crosslinked polymers (EVA, SBS, SB), powders of rubber, vegetable or petrochemical waxes without including synthetic, natural or modified natural gums, adhesion enhancers.

[0060] The binder advantageously comprises a fatty acid doping agent, facilitating rapid cohesion recovery. The fatty acid doping agent can be any fatty acid or derivative suitable for use in a bituminous material.

[0061] By "fatty acid" is meant a mono-, di- or tricarboxylic acid with an aliphatic chain, saturated or unsaturated, containing 10 to 28 carbon atoms, advantageously 12 to 20 carbon atoms.

[0062] Fatty acids can be of fossil, animal, vegetable, or synthetic origin. They may have undergone chemical functionalization. Animal origin refers, for example, to tallow. Vegetable origin refers to vegetable oils, which are advantageously chosen from sunflower, soybean, rapeseed, linseed, coconut, peanut, olive, corn, and castor oils, their derivatives, and mixtures thereof. These fats can also come from used oils from industry (food processing, papermaking, etc.).

[0063] By "fatty acid derivatives" is meant polymerized fatty acids.

[0064] Polymerized fatty acids include diacids or triacids of fatty acids or polyesters obtained by polymerization of a hydroxyacid.

[0065] By diacid or triacid of fatty acids, we mean any fatty acid functionalized by a new carboxylic acid function on at least one of the unsaturations of its hydrocarbon chain, said function having reacted with another carboxylic acid function of another fatty acid or, respectively, fatty diacid.

[0066] Fatty acids can be chemically functionalized and thus bear at least one chemical function selected from among alcohol, ester, epoxy, peroxide, carboxylic acid, and aldehyde functions, advantageously a carboxylic acid function. The fatty acids advantageously comprise at least one conjugated carbon-carbon double bond, and / or have undergone the grafting of maleic anhydride molecules onto a conjugated carbon-carbon double bond (leading to the formation of dicarboxylic acid functions on the hydrocarbon chain). This functionalization allows the production of diacids or triacids linking the fatty acids by oxygen bridges formed on their hydrocarbon chains.

[0067] Preferably, the fatty acid is chosen from the group consisting of oleic acid, linoleic acid, linolenic acid, and mixtures thereof.

[0068] The molecular mass of the diacid or triacid of fatty acids will preferably be between 600 and 800 g / mol.

[0069] Examples include, but are not limited to: - oleic fatty acids, such as RADIACID® 208 available from the company OLEON; - fatty acids from sunflower, coconut (RADIACID® 600), rapeseed D (RADIACID® 166), soybean (RADIACID® 110 and RADIACID® 121), palm, palm kernel or derivatives of pine oil (tall oil in English), castor oil; - tallow fatty acids, such as RADIACID® 401 and RADIACID® 403; - hydrogenated tallow fatty acids such as RADIACID® 408 and RADIACID® 409.

[0070] These fatty acids can also be in the form of dimers or trimers, such as RADIACID® 0951.

[0071] Hydroxy acid is advantageously a hydroxy acid of formula (I) [CHEM I] HO-C(O)-Ra-CRb(OH)-Rc where Ra is an aliphatic, C8-C2o, saturated or unsaturated hydrocarbon chain, possibly branched, possibly comprising one or more oxygen atoms, comprising a linear main chain of at least 8 carbon atoms; Rb, Rc each represent, independently of each other, H or an aliphatic hydrocarbon chain, in Ci-Ci0.

[0072] Advantageously, Ra meets one or more of the following characteristics, advantageously all of the following characteristics: - Ra is a linear hydrocarbon chain; - Ra is a hydrocarbon chain that can be saturated or unsaturated. The unsaturation, when present, is advantageously a C=C double bond or a C=C triple bond, more advantageously a C=C double bond. In one embodiment, Ra is a hydrocarbon chain that comprises 0 to 3 C=C double bonds, advantageously 0 to 2 C=C double bonds, more advantageously 0 or 1 C=C double bond; - Ra is a hydrocarbon chain in C8-Ci5, more advantageously in C10-C15.

[0073] In addition, Ra may comprise one or more oxygen atoms either interrupting the chain (ether functions) or hanging in the form of hydroxyl or ether functions in CrC6.

[0074] Advantageously, Rb represents H or a hydrocarbon chain, aliphatic, linear, saturated, more advantageously in Ci-C4. More advantageously, Rb represents H.

[0075] Advantageously, Rc represents a linear, aliphatic, saturated or unsaturated hydrocarbon chain. The unsaturation, when present, is advantageously a C=C double bond or a C=C triple bond, more advantageously a C=C double bond. In one embodiment, Rc is a hydrocarbon chain comprising 0 or 1 C=C double bond. Advantageously, Rc is a C4-C8 chain. Rc may include one or more oxygen atoms either interrupting the chain (ether functions) or hanging in the form of hydroxyl or ether functions in Ci-C6.

[0076] A hydroxy acid of formula (I) can be homopolymerized, or several hydroxy acids of formula (I) can be copolymerized. Furthermore, the polymerization reaction can be carried out in the presence of non-hydroxylated fatty acids, in particular saturated or unsaturated olefinic fatty acids comprising 8 to 30 carbon atoms, optionally substituted with a C1-C4 alkyl radical. Examples include oleic acid, palmitic acid, stearic acid, linoleic acid, 2-ethylhexanoic acid, etc. At least one hydroxy acid of formula (I), optionally in the presence of non-hydroxylated fatty acids, can also be copolymerized with a dicarboxylic acid.

[0077] The hydroxy acid is advantageously chosen from ricinoleic acid, 12-hydroxystearic acid and their combinations.

[0078] The fatty acid dope can be added to the binder in a mixture with the polymers added to the binder or in line.

[0079] The fatty acid dope content advantageously varies from 0.5% to 2.5% by weight, relative to the weight of the binder, more advantageously from 0.5% to 1.5% by weight.

[0080] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 6%, relative to the weight of the asphalt mix after drying. The binder includes the binder introduced as such (added binder) and the binder recovered from the asphalt aggregates, which may form part of the solid mineral fraction.

[0081] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 5.5%, relative to the weight of the asphalt after drying, when the mineral fraction comprises less than 30% by weight, relative to the weight of the dry mineral fraction, of asphalt aggregates.

[0082] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 6%, relative to the weight of the asphalt after drying, when the mineral fraction comprises at least 30% by weight, relative to the weight of the dry mineral fraction, of asphalt aggregates.

[0083] In cold-mix asphalt, the conventional residual anhydrous binder content is between 3.5% and 5.5% or 6%, depending on the aggregate content of asphalt, advantageously from 4.5% to 5.5% or 6%, depending on the aggregate content of asphalt, by weight relative to the total weight of the asphalt after drying for emulsion-based bituminous concretes or advantageously from 3.5% to 4.5% or 6%, depending on the aggregate content of asphalt, by weight relative to the weight of the asphalt after drying for an emulsion-based gravel.

[0084] In the process, during step a), the binder is in the form of an emulsion. The emulsion is a dispersion of the binder in water, the continuous phase of the system. It comprises an emulsifying composition including at least one cationic emulsifier.

[0085] The emulsifying composition content advantageously varies from 0.1% to 2% by weight, relative to the total weight of the emulsion, more advantageously from 0.13% to 1.2% by weight. The emulsifying composition content advantageously varies from 1 kg to 20 kg per tonne of emulsion, more advantageously from 1.3 kg to 12 kg per tonne of emulsion.

[0086] In an advantageous embodiment, the emulsifying composition principally comprises at least one amine. For the purposes of this invention, "principally" means that the emulsifying composition comprises at least 50% by weight, advantageously at least 80% by weight, up to 100% by weight, of an amine relative to the total weight of the emulsifiers. In particular, the amine may be selected from: - alkylpolyamines, including alkyldiamines; - fatty amines; - amidopolyamines; - quaternary ammonium compounds with fatty chains; - and their combinations.

[0087] Alkylpolyamines advantageously comprise one or two hydrocarbon radicals, saturated or unsaturated, comprising from 8 to 24 carbon atoms, more advantageously 12 to 22 carbon atoms, and / or its immediate cyclization derivatives as well as its oxyethylated or oxypropylated derivatives.

[0088] Alkylpolyamines advantageously correspond to the formula (II) [CHEM n]NRiR2- R3-(NR4-R5)x-NR6R7

[0089] in which: - x is an integer ranging from 0 to 3. Advantageously, x equals 0; - one or two of Rb R2, R6, R7, represents a hydrocarbon radical comprising 8 to 24 carbon atoms, more advantageously 12 to 22 carbon atoms, saturated or unsaturated, linear or branched, possibly cyclized. This radical advantageously derives from tallow fatty acids; - the other RB R2, R6, R7, each represent, independently of the others: a hydrogen atom; a hydrocarbon radical comprising from 1 to 6 carbon atoms, advantageously from 1 to 4 carbon atoms, more advantageously from 1 to 2 carbon atoms, saturated or unsaturated, linear or branched; or a radical -(CH2-CR8OH)ZH in which R8 is a hydrogen atom or a methyl radical, z is equal to 1 or 2. Advantageously the others of Rh R2, R6, R7, represent a methyl or ethyl radical; - R3 represents a hydrocarbon radical comprising 1 to 6 carbon atoms, saturated or unsaturated, linear or branched. Advantageously, R3 represents an ethylene or propylene radical; - R4, R5 each represent, independently of each other: a hydrogen atom; a hydrocarbon radical comprising from 1 to 6 carbon atoms, advantageously from 1 to 4 carbon atoms, more advantageously from 1 to 2 carbon atoms, saturated or unsaturated, linear or branched; or a radical -(CH2-CR8OH)ZH in which R8 is a hydrogen atom or a methyl radical, z is 1 or 2. Advantageously R4, R5 represents a methyl or ethyl radical.

[0090] As an example, one can cite trimethylpropylene diamine tallow.

[0091] Fatty amines respond advantageously to formula (III) [CHEM ni]NR9Rio- Ri 1 - R9 represents a hydrocarbon radical comprising 8 to 24 carbon atoms, more advantageously 12 to 22 carbon atoms, saturated or unsaturated, linear or branched, possibly cyclized. This radical is advantageously derived from tallow fatty acids; - Rio, represents: a hydrogen atom; a hydrocarbon radical comprising from 1 to 6 carbon atoms, advantageously from 1 to 4 carbon atoms, more advantageously from 1 to 2 carbon atoms, saturated or unsaturated, linear or branched; or a radical -(CH2-CR8OH)ZH in which R8 is a hydrogen atom or a methyl radical, z is 1 or 2. Advantageously R10 represents a methyl or ethyl radical; - Ri 1 represents a hydrocarbon radical comprising 1 to 6 carbon atoms, saturated or unsaturated, linear or branched. Advantageously, Ri 1 represents a methyl, ethyl, or propyl radical.

[0092] As an example, dimethylamine tallow can be cited.

[0093] Amidopolyamines respond advantageously to formula (IV) [CHEM IV]Ri’CO-(NH-Ri”)a-NH2

[0094] in which: - R / is a hydrocarbon residue, saturated or unsaturated, linear or branched, comprising 12 to 24 carbon atoms, advantageously 16 to 24 carbon atoms. This radical is advantageously derived from tall oil or tallow fatty acids; - Ri” is an ethylene radical; - a represents an integer from 2 to 5, preferably a equals 5; and / or its immediate cyclization derivatives, in particular imidazoline derivatives.

[0095] Amidopolyamine is advantageously the reaction product(s) of a fatty acid such as Tall Oil or tallow with diethanolamine, and / or diethylenetriamine, and / or tetraethylenepentamine and / or triethylenetetramine.

[0096] Quaternary ammonium compounds may in particular be of formula (V) [CHEM V](Rx)bN+(Ry)cY

[0097] in which: - Rx represents a hydrocarbon radical comprising 8 to 24 carbon atoms, more advantageously 12 to 22 carbon atoms, saturated or unsaturated, linear or branched, possibly cyclized; - Ry represents an alkyl radical comprising 1 to 6 carbon atoms, possibly hydroxylated, notably methyl, ethyl, propyl, hydroxyethyl, hydroxypropyl; - Y designates an anion of a mineral acid, in particular a chloride anion, or of an organic acid, in particular an acetate or formate anion; - c is an integer equal to (4-b) and - b can take the values ​​of 1, 2 or 3.

[0098] Among the surfactants relevant to this application, the following commercial products may be mentioned: - Dinoram®S (Ceca) or Redicote®E9 (Akzo Nobel): N alkyl tallow propylene diamine; - Emulsamine®L 60 (Ceca): Preparation based on tallol fatty amide, N-(3-dimethylamino)propyls (> 50%) and Emulsamine®LZ (> 25%) with an aromatic hydrocarbon (> 1%) and diethanolamine (> 1%); - Polyram®S (Ceca): N-alkyl tallow propylene polyamine with Dinoram®S (< 10%), alkyl tallow amines (Noram®S - < 5%), tallow nitrile (< 10%); - Stabiram®MS 601 (Ceca): N-alkyl tallow dichloride solution of N-dimethyl aminopropyl N-trimethyl ammonium (> 50%) in a water / hexylene glycol (glycol > 20%) mixture with Dinoram®S (< 1%); - Dinoram®O (Ceca): N-(C16 and Cl8 alkyl unsaturated)trimethyl diamine (oleic diamine); - Emulsamine®640 (Ceca): Preparation based on tallol fatty amides (> 50%), Dinoram®O (> 25%) and (Z)-octadec-9-enylamine (> 1%); - Indulin®R 66 (Meadwestvaco): Tall oil fatty amides: N - [(dimethylamino)-3-propyl]; - Indulin®R 33 (Meadwestvaco): Tall oil fatty amides (N-[(dimethylamino)-3-propyl]) (75-90%), N-tallow alkyltrimethylenediamine (20-25%); - Indulin®GE F2 (Meadwestvaco): Nonylphenol ethoxylate (25-35%), alkali lignin (reaction produced with dimethylamine and formaldehyde) (15-20%), N-(C14-18 alkyl and C16-18 unsaturated)-trimethylenediamine (5-10%); - Indulin®GE F2 (Meadwestvaco): C12-C14 ethoxylated alcohols (2.5-25%), alkaline lignin (reaction produced with dimethylamine and formaldehyde) (10-20%), N-(C14-18 alkyl and C16-18 unsaturated)-trimethylenediamine (1-3%); - Duomeen®TTM (Akzo Nobel): suiftrimethylpropylenediamine (90-100%), suifdimethylamine (5-10%); - Redicote®404 (Akzo Nobel): tallol, reaction products with tetraethylenepentamine (100%).

[0099] One or more of these surfactants may be used, alone or in mixtures.

[0100] Advantageously, the emulsifying composition comprises at least one alkylpolyamine and at least one amidopolyamine. The emulsifying composition may further comprise a fatty amine. Advantageously, the hydrocarbon binder cationic emulsion comprises, as emulsifiers: (1) at least one alkylpolyamine as defined above, in particular trimethylpropylene diamine tallow; (2) at least one amidopolyamine as defined above and / or its immediate cyclization derivatives; (3) possibly a fatty amine as defined above.

[0101] In this variant, the binder advantageously comprises a fatty acid dope as described above.

[0102] The emulsifying composition may also include a non-ionic emulsifying agent. This agent may be chosen from the family of ethoxylated fatty alcohols, the hydrophobic part of the molecule being of the nonylphenol-, octylphenol-, cetyl, oleic, etc. type, the hydrophilic part being made up of several ethoxy groups. Acid

[0103] The aqueous phase of the emulsifying composition also comprises a sufficient quantity of a mineral or organic acid (for example: citric acid, acetic acid), advantageously a mineral acid. The acid ionizes the cationic functions, particularly amines, of the emulsifiers to allow their dissolution in water.

[0104] The acid content is adjusted to the emulsifier content (depending on the nature of the aggregates, the application temperature, etc.) to have a pH of the aqueous phase between 1.5 and 8, advantageously between 1.5 and 7, more advantageously between 1.5 and 5.5, even more advantageously between 1.8 and 2.5.

[0105] The acid is advantageously hydrochloric acid, phosphoric acid or a polyphosphoric acid. Polyphosphoric acid is an oligomer of phosphoric acid comprising molecules according to one of the structural formulas PnO3n+i(n+21) in which n is an integer greater than or equal to 1, advantageously 1, 2 or 3, or P2O5>x(O2), in which x is between 0 and 1.

[0106] In the variant of the invention, in which the emulsifying composition comprises at least one alkylpolyamine and at least one amidopolyamine, the acid is advantageously phosphoric acid or a polyphosphoric acid. Solid mineral fraction:

[0107] By "solid mineral fraction", or "solid mineral fraction", these two expressions being used interchangeably, in the present description means all solid particles usable for the production of bituminous products for road construction, including in particular natural mineral aggregates (gravel, sand, fines) from quarries or gravel pits, recycled products such as asphalt aggregates resulting from the recycling of materials recovered during road repairs as well as surpluses from asphalt plants, shale in particular bauxite or corundum, rubber powders as well as their mixtures in all proportions.

[0108] The term "asphalt aggregates" means asphalt mixes (a mixture of aggregates and bituminous binders) obtained from milling asphalt layers, crushing slabs extracted from asphalt pavements, pieces of asphalt slabs, asphalt waste, or surplus asphalt production (production surpluses are materials coated or partially coated at the plant resulting from the transitional phases of manufacturing). These elements and other recycled products can reach dimensions of up to 14 mm.

[0109] The particle size of the mineral fraction, in particular of mineral aggregates, is measured by the tests described in standard NF EN 933-2 (July 2020 version).

[0110] The "solid mineral fraction" is also referred to as the "mineral fraction 0 / D". This mineral fraction 0 / D can be separated into two particle sizes: the mineral fraction 0 / d and the mineral fraction d / D.

[0111] The finest elements (the mineral fraction 0 / d) will be those in the range from 0 mm to a maximum diameter that can be set between 2 mm and 6 mm (from 0 / 2 to 0 / 6), advantageously between 2 mm and 4 mm. The other elements (minimum diameter greater than 2, 3, 4, 5 or 6 mm; and approximately up to 14 mm) constitute the mineral fraction d / D.

[0112] Advantageously, the mineral solid fraction comprises: - elements smaller than 0.063 mm (filler or fines); - elements, including sand, having a size between 0.063 mm and 2 mm; - elements, including gravel, having a size: - - between 2 mm and 6 mm; - - between 6 mm and 14 mm.

[0113] Advantageously, the 0.063 mm particle size of the solid mineral fraction varies from 4% to 10% by weight, relative to the weight of the dry solid mineral fraction. Thus, advantageously, 4% to 10% by weight, relative to the total weight, of the mineral fraction has a size less than or equal to 0.063 mm.

[0114] Advantageously, the 16 mm portion of the solid mineral fraction represents 100% by weight, relative to the weight of the dry solid mineral fraction. Thus, advantageously, 100% by weight, relative to the total weight, of the mineral fraction has a size less than or equal to 16 mm.

[0115] Advantageously, particularly for gravel emulsions, the 2 mm particle size of the mineral solid fraction varies from 30% to 50% by weight, relative to the weight of the dry solid mineral fraction. Thus, advantageously, 30% to 50% by weight, relative to the total weight, of the mineral fraction has a size less than or equal to 2 mm.

[0116] Advantageously, particularly for emulsion-based bituminous concretes, the 2 mm particle size of the mineral solid fraction varies from 20% to 40% by weight, relative to the weight of the dry solid mineral fraction. Thus, advantageously, 20% to 40% by weight, relative to the total weight, of the mineral fraction has a size less than or equal to 2 mm.

[0117] In one variant, the mineral solid fraction comprises less than 30% by weight, relative to the weight of the dry solid mineral fraction, of asphalt aggregates.

[0118] In another embodiment, the mineral solid fraction comprises at least 30% by weight, relative to the weight of the dry solid mineral fraction, of asphalt aggregates. Advantageously, the mineral solid fraction comprises up to 75% by weight, relative to the weight of the dry solid mineral fraction, of asphalt aggregates.

[0119] Generally, particle sizes of 0 / 4, 0 / 6, 0 / 6 discontinuous, 0 / 8, 0 / 8 discontinuous or 0 / 10 reconstituted are used, possibly with humidification to avoid segregation during transport.

[0120] The solid mineral fraction advantageously constitutes 94% to 96.5% by weight, advantageously 94% to 95.5% by weight, of the weight of the asphalt.

[0121] The process advantageously includes a step prior to step a) of humidifying the mineral solid fraction.

[0122] A mineral additive can be added to the solid mineral fraction to regulate the pH rise kinetics during step a) and improve the workability time, the It improves the emulsion's breaking quality and adhesive properties. This additive can be cement, lime, lime milk, or a calcium-magnesium milk.

[0123] The term “cement” means any hydraulic binder composed of finely ground inorganic material which, when mixed with water, forms a paste which sets and hardens as a result of reactions and hydration processes and which, after hardening, retains its strength and stability even underwater (NF P98-149 (2000-06-01) standards).

[0124] The term "calcium-magnesium milk" means an aqueous suspension of solid particles of a calcium-magnesium compound. Calcium-magnesium milks are more broadly defined in application WO 2016 / 005591.

[0125] The mineral additive content advantageously varies from 0.05 ppc to 1 ppc, by weight relative to the weight of the dry mineral solid fraction.

[0126] In the variant of the invention, in which the emulsifying composition comprises at least one alkylpolyamine and at least one amidopolyamine, a calcium-magnesium milk is advantageously added to the solid mineral fraction of the cement.

[0127] A retarder can also be added to the solid mineral fraction to adjust the workability time of the cold asphalt mix. This retarder is a cationic surfactant or other cationic compound that is dispersible or dilutable in water and that delays the setting of the material.

[0128] Fibers such as glass fibers or polyacrylonitrile fibers, advantageously with a size between 4 mm and 12 mm, can also be added to the solid mineral fraction. The fiber content advantageously varies from 0.05 ppc to 0.5 ppc (parts per cent by weight) / dry aggregates, preferably between 0.07 ppc and 0.2 ppc.

[0129] The mineral fraction described herein is that added in step a) of the process. The process advantageously includes a step prior to step a) of humidifying the solid mineral fraction. Others :

[0130] The emulsion may contain synthetic or natural latex. Latex is defined as a dispersion of polymers (styrene-butadiene, also known by the acronym SBR for "styrene butadiene rubber", acrylic, or styrene-acrylic), crosslinked or not, in the aqueous phase. This latex is incorporated into the aqueous phase before emulsification, in-line during the emulsion manufacturing process, or even after the emulsion has been manufactured.

[0131] While not a preferred variant, fluxing agents of petroleum origin or derived from agricultural resources may also be added. These fluxing agents may be added during the emulsion preparation or during step a) of the process.

[0132] The fluxing agent is advantageously a fluxing agent of petroleum or petrochemical origin. A petroleum fluxing agent is a product obtained from the distillation of crude oil. (light fraction(s)), which may have undergone a hydrotreating operation. In particular, the fluxing agent is chosen from the group consisting of fluxing agents marketed by Total (Greenflux® 2000®, Greenflux SD) or by Exxon (Varsol®).

[0133] The fluxing agent is advantageously a fluxing agent of natural, non-fossil origin (plant or animal origin). A fluxing agent of natural, non-fossil origin consists of a natural, non-fossil oil, its derivatives such as fatty acid esters, and combinations thereof. These fluxing agents of natural, non-fossil origin are well known to those skilled in the art.

[0134] Preferably, vegetable oils such as sunflower, rapeseed, peanut, coconut, linseed, palm, soybean, olive, castor, corn, pumpkin, grapeseed, jojoba, sesame, walnut, hazelnut, tung oil, tall oil, their derivatives, and combinations thereof, will be used.

[0135] In particular, the non-fossil natural fluxing agent is chosen from the group consisting of: - esters, in particular monoesters including methyl monoesters, or amides, possibly functionalized by oxidation, obtained from vegetable or animal oils (pine, sunflower, rapeseed, linseed, castor, peanut, coconut, olive, palm, cottonseed, corn, tallow, lard, palm kernel, soybean, pumpkin, grapeseed, jojoba, sesame, walnut, hazelnut, tung, rice oil - as described in applications FR 2 786 603, FR 2 910 477, EP 900 822, FR 2 721 043 or FR 2 891 838), and their combinations; - heavy oils of mineral origin, animal and vegetable oils and fats, and their functionalized derivatives with transesterification products and saponification products and their combinations (as described in application AT 406 375); and their combinations.

[0136] A drying additive, such as manganese octoate, may be added to these oils and derivatives in order to promote oxidation reactions.

[0137] Advantageously, as already mentioned, no synthetic, natural or modified natural gum is added, in particular no gum as described in application FR 2 927 328 or EP 2 090 620

[0138] During step a), all the constituents described above are mixed in the mixer of the self-propelled machine to form a hydrocarbon coating.

[0139] During step a), the mixture can be kneaded without breaking the emulsion advantageously for a few tens of seconds, preferably for at least 90 seconds.

[0140] During step a), the emulsion breaks down properly. The quality of the breakage can be examined in the laboratory by measuring the breakage time of the emulsion in question. with the solid mineral fraction. The setting time, also called the breaking time, corresponds to the time required for the hydrocarbon binder emulsion to completely break down after contact with the solid mineral particles. A sample of the asphalt mix is ​​placed in a glass of colorless water at different times, after its workability has decreased. If the water changes color, this means that droplets of hydrocarbon binder are still "free" and are not in contact with the solid mineral particles. The more cloudy the water becomes, the more significant this phenomenon is. There is a scale from 0 to 5 for comparing these color indices.

[0141] Within the framework of the present invention, the breaking time is advantageously less than 10 min and a color index of 0 (colorless) is advantageously obtained 10 minutes after contacting the hydrocarbon binder emulsion with the mineral solid particles.

[0142] The self-propelled machine combines the functions of dosing, mixing and implementing the mixture.

[0143] Advantageously, the self-propelled machine comprises, in addition to the mixer: - a feed hopper for solid mineral particles; - an emulsion tank; - a smoothing sled or a finishing sled; - a water tank; - optionally a hopper for powdered materials, such as lime or cement, and / or a vat for lime slurry or calcium-magnesium slurry; - optionally a fiber dosing system; - optionally an additive tank.

[0144] The equipment is generally mounted on a tractor or semi-trailer. A self-propelled machine that can be used is shown in [Fig. 1].

[0145] [Fig.1]

[0146] Self-propelled machine mounted on a semi-trailer comprising: 1: an emulsion tank; 2: a water tank; 3: a granule hopper; 4: a powder hopper; 5: a mixer; 6: a sled.

[0147] The solid mineral fraction is loaded into the aggregate hopper. It is then conveyed to the mixer, advantageously by an extraction conveyor whose speed can vary according to the machine's forward speed on the construction site. A weighing system for the solid mineral fraction can be provided. The capacity of the aggregate hopper advantageously varies from 4 m³ to 16 m³, or advantageously from 5 m³ to 14 m³.

[0148] The hydrocarbon binder cationic emulsion is stored in the emulsion tank, the capacity of which advantageously varies from 1 m³ to 10 m³, or advantageously from 4 m³ to 8 m³. Advantageously, a volumetric pump supplies the mixer with the emulsion. The feed rate is advantageously adjusted according to the machine's forward speed on the construction site and the feed rate of solid mineral fraction into the mixer.

[0149] The quantity of water stored in the water tank advantageously varies from 1 m3 to 8 m3, advantageously from 4 m3 to 8 m3.

[0150] The mixer is advantageously a continuous mixer with two parallel shafts. The number of blades on the two shafts varies from 20 to 80, advantageously from 32 to 60. The screw rotation speed varies from 200 to 800 rpm, advantageously from 300 to 600 rpm.

[0151] The length of the mixer varies advantageously from 100 cm to 200 cm, advantageously from 130 to 150 cm.

[0152] Any application sled can be used. The sled, also called a screed, may include one or more joints to adapt to the profile of the substrate on which the asphalt will be laid. A paver can also be used.

[0153] The machine advantageously includes at least one control system for maintaining constant proportions of the asphalt mix constituents during step a) of the process and / or step b) of the process. Adjustments in water and possibly in additive(s) can advantageously be made from a control panel.

[0154] During step b), the cold-mix asphalt, directly from the mixer of the self-propelled machine, is applied to form a layer with a thickness of at least 2 cm. The thickness of this layer can advantageously be up to 5 cm.

[0155] This layer is then compacted during step c) of the process.

[0156] Once the construction site has started, steps a) and b), and also c), are generally concurrent.

[0157] The compacted road surface layer advantageously has a thickness ranging from 1.5 cm to 8 cm, advantageously between 2 cm and 5 cm. The road surface layer is advantageously selected from a wearing course having a thickness ranging from 1.5 cm to 3 cm, advantageously from 2 cm to 3 cm, a wearing course having a thickness ranging from 3 cm to 5 cm, a wearing course having a thickness ranging from 5 cm to 8 cm, a base course, a resurfacing, or a reprofiling. The thickness here corresponds to the thickness of the layer after compaction, i.e., after step c).

[0158] Emulsion-based bituminous concretes are advantageously used as wearing courses. Therefore, emulsion-based bituminous concretes must withstand the stresses of traffic and weathering throughout their service life. Advantageously, after step c) of the process, emulsion-based bituminous concretes have a thickness of between 1.5 cm and 8 cm, in particular between 2 cm and 3 cm, between 3 cm and 5 cm, or between 5 cm and 8 cm. Emulsion-based bituminous concretes have a void content, measured according to the modified Duriez test (NF P 98-251-4, compaction method no. 1), of 15% or less.

[0159] Heavy emulsions are usually used: - in maintenance work on an existing roadway for reprofiling work, localized repairs; - in new construction: for base layers or bonding layers; - in general reloading or reinforcement.

[0160] They are normally then covered with at least one wearing course. The heavy emulsions advantageously have a thickness, after step c) of the process, of between 1 cm and 15 cm. The thickness is adapted according to the intended use.

[0161] Production rates vary advantageously from 30 tonnes to 150 tonnes of asphalt / hour, more advantageously from 70 to 120 tonnes of asphalt / hour.

[0162] The process according to the invention provides good coating of the mineral solid fraction, including the largest particles. In particular, more than 90% of the surface of the mineral solid fraction is coated. More specifically, more than 97% of the surface of the mineral solid fraction is coated. Even more specifically, 100% of the surface of the mineral solid fraction is coated, meaning that no surface of the mineral solid fraction is exposed.

[0163] The coating quality after 24 hours of curing is advantageously at least class E2 for a hydrocarbon asphalt for wearing course according to standard NF P 98-257-1, i.e. at least 90% of the mineral surface covered, more advantageously at least class El i.e. at least 97% of the mineral surface covered.

[0164] The color index at 10 minutes of the coating obtained by the process according to the invention is advantageously less than 2, even more advantageously less than 1.

[0165] The color index allows for the evaluation of the state of rupture of the bitumen emulsion upon contact with solid mineral fractions after a resting time of 10 minutes. The test consists of taking a mass of asphalt (approximately 10 grams) 10 minutes after the asphalt has been produced and then introducing this mass of asphalt into a volume of 100 mL of clear water. The color of the water upon contact with the mass of asphalt indicates the state of rupture of the emulsion. This color is rated from 0 to 5, with a color rating of 0 corresponding to clear water, signifying complete rupture of the the emulsion and the colour score 5 corresponding to water strongly coloured black synonymous with an absence of emulsion break.

[0166] The cohesion time of the coating obtained by the process according to the invention is advantageously less than 2 hours, advantageously less than 1 hour, even more advantageously less than 30 min.

[0167] The cohesion time corresponds to the time required for the cold asphalt mix to develop strong cohesion. The test performed is sensory and is carried out by handling the cold asphalt mix at different curing times at ambient temperature.

[0168] The process according to the invention also allows satisfactory handling of the asphalt.

[0169] Workability time, also called fluidity or consolidation time: the time determined as the duration between (1) the start of mixing the solid mineral fraction and the bitumen emulsion (beginning of step a)) and (2) the setting of the cold asphalt mix (after step c)). In order to evaluate the workability time of a cold asphalt mix, to ensure application by the paving machine, laboratory tests are carried out in a container on batches of 400 g to 1000 g of dry material. After mixing the constituents, the change of state of the cold asphalt mix (transition from liquid to paste) is assessed by manually stirring with a spatula at a constant speed (approximately 1 rpm). The observed change of state gives the setting time.

[0170] This test is carried out at a controlled temperature (typically between 20 and 25 °C). The requirements are a setting time greater than 30 s, advantageously greater than 40 s, more advantageously greater than 90 s, even more advantageously between 90 s and 180 s, even more advantageously between 90 s and 120 s.

[0171] Cold-mix asphalt obtained by the process according to the invention advantageously meets the requirements mentioned in the IDRRIM guide "Factory-made emulsion asphalts" and / or in the NF P 98-121 and NF P 98-139 standards depending on the nature of the asphalt formulated, in particular compaction ability, compressive strength and water resistance.

[0172] Compaction suitability defines the ability of cold-mix asphalt to achieve a specified void content under defined conditions. Compaction suitability is measured according to the PCG gyratory shear press compaction test (NF P 98-252 - June 1999). Compaction is achieved by kneading, under low static compression, a cylinder of hydrocarbon mixture contained in a mold limited by pellets and maintained at a fixed temperature. Compaction is achieved by the combination of gyratory shear and a resulting axial force. applied by a mechanical head. This method makes it possible to determine the evolution of the percentage of voids in the specimen as a function of the number of gyrations.

[0173] Compressive strength and water resistance are measured according to standard NF P98-251-4. This method aims to determine, for two compaction methods, the percentage of voids and the water resistance, at 18°C ​​and / or 35°C, of ​​a cold hydrocarbon mixture from the ratio of compressive strengths with and without immersion of the specimens.

[0174] The stiffness modulus is measured according to standard NF EN 12697-26 annex C, June 2018.

[0175] The process according to the invention makes it possible to prepare hydrocarbon coatings having the desired coating and possessing a rise in cohesion and hardening sufficiently rapid in order to allow a rapid return to traffic, in particular in less than one hour, more advantageously in less than 30 minutes. Examples

[0176] Example 1: Cold-mix asphalt for wearing course (Bitumen emulsion concrete - BBE)

[0177] Emulsion bituminous concretes (BBE) are defined by the French standard NF P98-139 (December 2016) and also described in the IDRRIM guide "Factory-made emulsion-based asphalt mixes".

[0178] Different emulsions were first manufactured:

[0179] [Tables] Formula Number Fl F2 Binder Bitumen Supplier Shell Shell Grade 70 / 100 50 / 70 Content (kg / t) 650 596.4 Additive Supplier - Ingevity Name - Radiacid 166 Content (kg / t) - 3.6 Aqueous Phase Emulsifiers Supplier Ingevity Arkema Nouryon Name Indulin GE F2 Polyram S Redicote C32 0E Content (kg / t) 4 5 9 Acid Nature Hydrochloric acid Phosphoric acid Content (kg / t) 5 9 Water (kg / t) 336 382

[0180] Radiacid 166: rapeseed fatty acid anionic surfactant

[0181] Indulin GE F2: cationic surfactant (mixture comprising ethoxylated alcohols, CAS: 68439-50-9; reaction products lignin, dimethylamine and formaldehyde, CAS: 110152-58-4 and alkyl diamines, CAS: 68439-73-6)

[0182] Polyram S: cationic surfactant (mixture comprising more than 80% alkylpolyamines, CAS: 68911-79-5; less than 10% alkyldiamines, CAS: 61791-55-7 and less than 5% alkylamines, CAS: 61790-33-8)

[0183] Redicote C320E: cationic surfactant (mixture comprising 60-70% trimethylpropylene diamine tallow, CAS: 68783-25-5 and 30-40% products of the reaction of tallol with tetraethylenepentamine, CAS: 68555-22-6)

[0184] The contents in Table 1 are the contents of the commercial product. Hydrochloric acid has a concentration of 37% and phosphoric acid of 85%.

[0185] These emulsions were manufactured using a laboratory Atomix C mill.

[0186] From these bitumen emulsions, cold-mix asphalt is prepared either by hand with a mass of 500g of material, or using a parallel shaft mixer from SR Consulting for a mass of 25 kg of material.

[0187] The tests were carried out on dioritic type mineral solid particles.

[0188] The solid mineral fraction comprises, by weight relative to the total weight of the dry mineral fraction: - 30.0% sand by weight Dus bag 0 / 2; - 45.0 of Dussac 2 / 6 aggregates; - 25.0 of Dussac 6 / 10 aggregates

[0189] The cut 0 / 2 corresponds to the fraction 0 / d.

[0190] The 2 / 6 and 6 / 10 cuts together form the fraction d / D.

[0191] This mineral fraction allows the manufacture of a 0 / 10 asphalt mix.

[0192] The solid mineral fraction is characterized by a 0.063 mm sieve size of 5.1% (51.1% by weight of the solid mineral fraction has a size less than 0.063 mm) and by a 2 mm sieve size of 30.7% (30.7% by weight of the solid mineral fraction has a size less than 2 mm; the additional 0.7% compared to the 0 / d fraction corresponds to the fine element impurities of the d / D fraction).

[0193] The characteristics of the prepared cold-mix asphalt are given in the following Table 2:

[0194] [Tables2] BBE RI BBE II BBE 12 BBE 13 Solid Mineral Fraction As described above Bitumen emulsion - natural Fl F2 F2 F2 Bitumen emulsion - content 7.1 ppc 8.4 ppc 9.1 ppc 9.7 ppc Fluxant - content 0.2 ppc - - - Fluxant - natural Oléoflux® dried* - - - Total water content 8.0 ppc 11 ppc 10 ppc 10 ppc Conventional residual anhydrous binder content (tic) 4.58% 4.8% 5.2% 5.5%

[0195] *dried with 4% by mass of Octa soligen® Manganese 10 HS from Borchers

[0196] Cold-mix asphalt BBE RI is the reference asphalt manufactured using a sequencing method. The d / D aggregates are first coated with 1 / 3 The total emulsion mass is mixed for 8 seconds, then the 0 / d sand, moistened with the added water, is introduced into the mixture along with the remaining 2 / 3 of the emulsion mass, and the mixture is kneaded for 9 seconds. At the end of kneading, the fluxing agent is added to the mixture while stirring, and then the mixture is kneaded for a further 3 seconds.

[0197] Cold-mix asphalt BBE II, BBE 12, and BBE 13 are asphalt mixes according to the invention. The entire mineral solids fraction (0 / D) is moistened with feed water, then the entire emulsion is added to the mineral solids fraction. The mixture (400-500 g) is then vigorously mixed for 15 seconds (5 rpm) to simulate coating in the mixer of an application machine. The mixture is then mixed less vigorously (1 rpm) for up to 90 seconds to simulate the passage of the cold-mix asphalt through the sled of the application machine.

[0198] The coating, workability time, breaking time or 10-minute color index, compactability (PCG), and compressive strength of these emulsion-based asphalt concretes according to the invention are evaluated. Cold-mix asphalt is also evaluated without considering workability time and breaking time.

[0199] There are no existing tests for evaluating the cohesion of infant formula (IF) at an early age. Therefore, cohesion is generally assessed visually at 1 hour and 24 hours. To highlight the superior cohesion of the formulas of the invention, a simple test, known as the fracture test, has been developed to provide quantitative values.

[0200] Three kilograms of asphalt mix are prepared by mixing the solid mineral fraction and the cationic bitumen emulsion for 20 seconds. BBE RI is prepared by a sequential coating process, while BBE II, 12, and 13 are prepared by a direct coating process. For the sequential coating process, the sequencing steps consist of mixing the d / D aggregates for 8 seconds with a first portion of the emulsion (generally one-third of the total emulsion mass), then adding the 0 / d fraction, possibly with the asphalt aggregates and the second portion of the emulsion (generally two-thirds of the total emulsion mass), mixing for 9 seconds, and finally adding the fluxing agent, if applicable, while mixing the mixture for up to 20 seconds of total mixing time.

[0201] Four asphalt slabs measuring 120*120*20 mm are then prepared: - in the case of BBE RI, the industrial process is adapted by leaving the asphalt in a loose state for 4 hours at 18°C, representing a significant transport time, then by breaking up the pile of asphalt to simulate the passage of the asphalt through the augers of the paver, to prepare the test slabs by compacting them with a manual roller (6 passes) to reach a thickness of 2 cm. The slabs then undergo a ripening at 18°C ​​and 55% humidity for 1 hour or 24 hours before performing the fracture test - In the case of BBE II, 12 and 13, the asphalt mix is ​​poured into the same molds but directly after mixing. A thickness of 2 cm is applied without compaction this time. The slabs then undergo curing at 18°C ​​and 55% relative humidity for 1 hour or 24 hours before the fracture test is performed.

[0202] After curing for 1 hour or 24 hours, the BBE plate is removed from the mold and positioned on a flat surface with a hatch opening onto a void. The plate is placed with a counterweight on its fixed part (the part placed on the surface without the hatch), and half of the plate is placed in the void once the hatch is opened. The time required for the plate to break after the hatch is opened is then measured. The result is given in seconds and represents the fracture time. The longer the time, the more resistant the BBE is to bending, and therefore the more advanced the cohesion development.

[0203] Cohesion is judged to be "very weak" if the fracture time is less than 5s, "weak" if the fracture time is between 5s and 20s, "strong" if the fracture time is between 20s and 50s and "very strong" if the fracture time is greater than 50s.

[0204] The results obtained are shown in the following table:

[0205] [Tables3] Specifications* BBE RI BBE II BBE 12 BBE 13 Coating at 24h El El El El El Workability time (s) - - 100 110 130 Color index at 10 min - 0 0 0 1 Cohesion at 1h - Very Low Strong Strong Strong Cohesion at 24h - Low Very High Very High Very High DURIEZ TEST (NF P98-251-4) % voids (modification 1) Value to declare 14.4 13.1 11.5 10.4 % voids (modification 2) <22 19.4 18.9 17.9 16.9 Compressive strength without immersion according to modality 1 (R in MPa) >2.0 3.02 6.92 6.96 6.83 Ratio r18 / R18 >0.70 0.85 0.86 0.86 0.93 Ratio r35 / R35 >0.80 0.93 0.94 0.95 0.96 COMPACTION TEST WITH GIRATORY SHEAR PRESS (NF P 98-252) % void at V25 <26 24.3 24.8 22.9 24.4 STIFFNESS MODULE TEST (NF EN 12697-26 Annex C, June 2018) Rigidity modulus (MPa) Value to be declared 3256 4419 4075 3790

[0206] * BBE type 2 TM specifications as defined in standard NF P 98-139:2016-12

[0207] The results presented in the table above demonstrate that it is possible to obtain very good coating using the process according to the invention. It is also possible to obtain a working time compatible with the production of cold asphalt using a self-propelled machine.

[0208] According to the process of the invention, cold-mix asphalt exhibits a significantly faster and stronger cohesion build-up than cold-mix asphalt manufactured according to the known methodology. The minimum mechanical specifications required by standard NF P 98-139 are largely met. A marked increase in compressive strength is observed for cold-mix asphalt according to the invention compared to asphalt manufactured according to the known methodology.

Claims

Demands

1. A process for manufacturing a road surface layer based on cold-mix asphalt, comprising the following steps: a- coating at ambient temperature in a mixer of a self-propelled machine a mineral solid fraction with a cationic emulsion of hydrocarbon binder, water is introduced into the mixer at a concentration such that the total water is between 8 ppc and 14 ppc relative to the weight of the dry solid mineral fraction to form a cold-mix asphalt in which the conventional residual anhydrous binder content as described in standard NF P 98-139:2016-12 varies from 3.5 to 6%, relative to the weight of the asphalt after drying b- placing the cold-mix asphalt directly from the outlet of the mixer of the self-propelled machine to form a layer having a thickness of at least 2 cm; c- then compaction of the layer implemented during step b) to form the road surfacing layer.

2. A process according to claim 1, wherein the hydrocarbon binder cationic emulsion comprises as an emulsifier at least one amine, the amine representing at least 50% by weight of the total weight of the emulsifiers.

3. A method according to claim 2, wherein the amine is selected from: - alkylpolyamines, including alkyl diamines; - fatty amines; - amidopolyamines; - fatty chain quaternary ammoniums; - and their combinations.

4. A process according to any one of the preceding claims, wherein the hydrocarbon binder cationic emulsion comprises, as emulsifiers: (1) at least one alkylpolyamine, comprising one or two radicals selected from a saturated or unsaturated hydrocarbon residue comprising 8 to 24 carbon atoms and / or its immediate cyclization derivatives as well as its oxyethylated or oxypropylated derivatives; and (2) at least one amidopolyamine of formula (IV) Ri'CO-(NH-Ri”)a-NH2, Ri' being a hydrocarbon remainder, saturated or unsaturated, comprising from 12 to 24 carbon atoms, Ri” an ethylene radical, has an integer from 2 to 5 and / or its immediate cyclization derivatives; the cationic emulsion comprises a mineral acid selected from phosphoric acid or a polyphosphoric acid; and the binder comprises a fatty acid dope or fatty acid derivative.

5. A method according to any one of the preceding claims, wherein the cold-mix asphalt is selected from emulsion-bound gravels or emulsion-bound bituminous concretes.

6. A method according to any one of the preceding claims, wherein 4% to 10% by weight of the solid mineral fraction has a size less than or equal to 0.063 mm, relative to the weight of the dry solid mineral fraction.

7. A method according to any one of the preceding claims, wherein 100% by weight of the solid mineral fraction has a size less than or equal to 16 mm, relative to the weight of the dry solid mineral fraction.

8. A method according to any one of the preceding claims, wherein 30% to 50% by weight of the solid mineral fraction has a size less than or equal to 2 mm, relative to the weight of the dry solid mineral fraction.

9. A method according to any one of claims 1 to 7, wherein 20% to 40% by weight of the solid mineral fraction has a size less than or equal to 2 mm, relative to the weight of the dry solid mineral fraction.

10. A method according to any one of the preceding claims, wherein the mineral solid fraction constitutes 94% to 96.5% by weight, advantageously 94% to 95.5% by weight, of the weight of the asphalt.

11. A method according to any one of the preceding claims, wherein the coating does not comprise gum.

12. A process according to any one of the preceding claims, wherein in step a) water is introduced into the mixer in such a proportion that the total water is between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction.

13. A process according to any one of the preceding claims, comprising a step prior to step a) of humidifying the mineral solid fraction.

14. A method according to any one of the preceding claims, wherein the road surface layer is selected from a wearing course having a thickness ranging from 2 cm to 3 cm, a wearing course having a thickness ranging from 3 cm to 5 cm, a wearing course having a thickness ranging from 5 cm to 8 cm, a base course, a resurfacing or a reprofiling.

15. A method according to any one of the preceding claims, wherein the self-propelled machine comprises in addition to the mixer: - a feed hopper for solid mineral particles; - an emulsion tank; - a smoothing sled or a finisher; - a water tank; - optionally a hopper for powders, such as lime or cement, and / or a lime slurry tank; - optionally a fiber dosing system.

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