Method for producing a road surface layer based on a hydrocarbon cold mix

Abstract

The invention relates to a method for producing a road surface layer based on a hydrocarbon cold mix, the method comprising the following steps: a) coating at room temperature in a mixer of a self-propelled machine a mineral solid fraction with a cationic hydrocarbon binder emulsion, water being added to the mixer to make the total water content thereof between 8 ppc and 14 ppc relative to the dry solid mineral fraction to form a hydrocarbon cold mix in which the typical content of the 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 mix after drying; b) applying the hydrocarbon cold mix directly at the output of the mixer of the self-propelled machine to form a layer having a thickness of at least 2 cm; and subsequently c) compacting the layer applied in step b) to form the road surface layer.

Description

[0001] METHOD FOR PRODUCING A ROAD SURFACE LAYER

[0002] COLD HYDROCARBON COATING BASED

[0003] FIELD OF THE INVENTION:

[0004] The present invention relates to the field of hydrocarbon coatings 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 hydrocarbon coatings with rapid cohesion.

[0005] TECHNOLOGICAL BACKGROUND:

[0006] Hydrocarbon coatings

[0007] Among the hydrocarbon coatings, there are two main families: hot hydrocarbon coatings and cold hydrocarbon coatings.

[0008] Hot mix asphalts are obtained by hot mixing aggregates and a hydrocarbon binder. The aggregates are heated, generally to a temperature above 100°C. These asphalts have a good coating, good workability and mechanical properties after application and cooling in accordance with the expectations of those skilled in the art. The cohesion of these asphalts is clear and rapid and is achieved by cooling the coating in a few hours.

[0009] Cold-mix asphalt mixes are obtained by cold mixing of mineral solid particles, possibly moistened, with an emulsified hydrocarbon binder. The use of cationic hydrocarbon binder emulsion allows coating without drying or heating of the mineral solid particles due to the low viscosity of the hydrocarbon binder emulsion at a temperature close to room temperature. The cold production of these asphalt mixes allows a significant reduction in the energy consumption required for hot-mix asphalt mixes to dry and heat the mineral solid particles. Cold-mix asphalt mixes are therefore recognized for reducing the environmental footprint of hydrocarbon mixes during the manufacturing stages.

[0010] Cold-mixed asphalt and cold-mixed bituminous materials

[0011] The cold-mixed hydrocarbon mixes according to the invention have the properties of the emulsion mixes described in the guide Emulsion mixes manufactured at the factory, Cerema, 2020 or in the old standards NF P 98-139:2016-12 and NF P 98-121:2014-10. The characteristic mechanical performances of cold-mixed hydrocarbon mixes are in particular:

[0012] - compressive strength, water resistance, seen through a Duriez test (NF P 98-251-4: August 2004);

[0013] - the compaction suitability seen through the compaction test using the gyratory shear press (NF P 98-252: June 1999);

[0014] - the rigidity modulus (NF EN 12697-26 annex C, June 2018).

[0015] The cold-mixed asphalt mixes according to the invention are distinct from cold-poured bituminous materials. Cold-mixed asphalt mixes comply with different formulation rules than cold-poured materials and their implementation is different. Finally, their mechanical performance is evaluated via different laboratory tests.

[0016] 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 old standard NF P 98 150. Cold-poured bituminous materials have a residual binder content greater than 5.5 ppc (part per cent by weight), relative to the weight of the dry solid mineral fraction.

[0017] The characteristic mechanical performances of cold-poured bituminous materials are:

[0018] - the setting or fluidity time: time determined as the duration between the start of mixing of the constituents and the setting of the MBCF; - the breaking time: time for which the emulsion in the MBCF is completely broken;

[0019] - cohesion time: time for which the cohesion of the MBCF is sufficient for opening to traffic;

[0020] - resistance to wear (or abrasion): test carried out after a more or less long curing period to ensure the durability of the MBCF under traffic.

[0021] Application FR 2 927 328 describes a method for manufacturing a cold-poured coating capable of being applied to a high thickness of at least 1.5 cm, said coating comprising the following constituents:

[0022] - a hydrocarbon binder in the form of a cationic emulsion

[0023] - aggregates,

[0024] - supply water and,

[0025] - at least one additive.

[0026] 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 flow or to the supply water prior to mixing all of said constituents. However, application FR 2 927 328 refers to the field of cold-poured asphalt mixes according to the definition of standard NF P 98 150. Application FR 2 927 328 does not at any time describe a method for preparing a cold-poured asphalt mix as defined in standards NF P 98-139:2016-12 and NF P 98-121:2014-10.

[0027] Cold-mixed hydrocarbon coatings

[0028] The binder used for the manufacture of hydrocarbon binder emulsions is bitumen, polymer-modified bitumen, a synthetic petroleum binder and / or a vegetable binder. The binder can be fluxed or fluidized by products of petroleum or vegetable origin.

[0029] When a cationic bitumen emulsion is used as a binder, the resulting cold-mix hydrocarbon coatings are divided into two product categories:

[0030] - emulsion gravels (GE) for base and bonding layers and reprofiling; - emulsion bituminous concretes (BBE) for wearing courses.

[0031] The manufacturing temperature of cold mixes, which is close to room temperature (the recommended minimum temperature is around 10°C, the range therefore advantageously extends from 10°C to 40°C), gives the binder, after breaking of the emulsion, a very important role in the workability and compactibility of the mix. In this temperature range, the high viscosity of the binder reduces the compactibility of the mix and thus reduces the mechanical properties of the resulting mix.

[0032] Cold mixes overcome many of the constraints associated with hot mixes. However, cold mixes have technical flaws and limitations.

[0033] First of all, the reactivity of the hydrocarbon binder emulsion with the mineral solid particles sometimes leads to a coating quality defect, especially when the mineral solid particles contain a high content of fines. Indeed, the more fines the granular fraction contains, the worse the distribution of the binder will be on the granular fraction (mainly on the large elements). In addition, this coating defect can be accentuated by the numerous handlings of the mix (transport, passage through the paver screws, compaction) which lead to problems of stripping by 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 mixes are very sensitive to the total water content of the mix which generates workability problems when the water content is too high.

[0034] Workability is also a technical limitation inherent to cold mixes. During the transport time of the mix between the mixing plant and the construction site, the increase in cohesion occurs following the breaking of the emulsion upon contact with the solid mineral particles. This increase in cohesion is generally delayed by several means including the reduction of the binder content of the mix, the use of fluxing agents or the use of very slow-breaking surfactants. These actions have a positive effect on the workability of the mix during transport but also have a detrimental effect on the increase in cohesion of the mix once it has been applied to the road surface.

[0035] To remedy or limit the problems of poor distribution of the bitumen film over the entire granular fraction, the step of mixing the granular fractions and the emulsion binder can be sequenced. Indeed, while emulsion gravels and cold asphalt mixes for bedding or reprofiling are normally manufactured by simple coating, emulsion bituminous concretes (BBE) and cold asphalt mixes for wearing courses generally use a sequenced coating due to the need to obtain a very good coating for these surface coverings. Sequencing methods are described in patents EP 0 384 094, EP 0 524 031, EP 0 781 887 and FR 2 960 890.

[0036] In order to improve the behavior of cold mixes, particularly in terms of coating, workability and cohesion, various methods including a heating step have been proposed, particularly in patents EP 0 552 574, FR 2 732 239 and EP 1 668 184.

[0037] The technological background demonstrates the benefits of certain processes to improve the cold-mix performance of asphalt mixes. Properties such as coating, workability and cohesion recovery can be optimized by sequencing the addition of mineral solid particles and binder or by a heating step.

[0038] There remains a need for the provision of new solutions to significantly increase the cohesion of cold asphalt mixes, particularly for wearing courses, while ensuring good coating of the mix. This is to improve the early-age shear strength of cold asphalt mixes and thus enable wider use of these coatings, particularly for heavier traffic. The aim of the present invention is therefore to address the technical limitations mentioned above and to propose a method for manufacturing a cold asphalt mix that allows:

[0039] - to avoid the need for sequencing to obtain a good coating of the asphalt, regardless of the petrographic nature of the solid mineral particles;

[0040] - to overcome the numerous handling problems associated with the central production of cold hydrocarbon coatings;

[0041] - to avoid the use of fluxing agents which improve workability and compactibility but inhibit the rapid increase in cohesion of cold hydrocarbon coatings;

[0042] - to control the coalescence of the hydrocarbon binder emulsion;

[0043] - to improve the cohesion of cold hydrocarbon coatings without a heating process;

[0044] - to increase the short, medium and long term mechanical resistance of cold hydrocarbon coatings.

[0045] To this end, the applicant has discovered that the production of a cold asphalt mix in situ on site using a self-propelled machine equipped with a mixer would make it possible to achieve the above objectives and to solve the problems of the prior art. The applicant has also discovered that despite the reduced size of the mixer of a self-propelled machine, it is possible to meet the coating requirements of cold asphalt mixes by adapting an abnormally high water content for a cold asphalt mix.

[0046] A self-propelled machine can meet coating requirements without specific material sequencing and with very different mixer geometries.

[0047] The applicant has discovered that the formulations according to the invention make it possible to prepare cold hydrocarbon coatings which can be manufactured in situ and thus make it possible to circumvent the problems linked to transport. BRIEF DESCRIPTION OF THE INVENTION:

[0048] The subject of the invention is a method for manufacturing a road surfacing layer based on cold hydrocarbon mix, comprising the following steps: a) coating at room temperature in a mixer of a self-propelled machine a solid mineral fraction with a cationic emulsion of hydrocarbon binder, water is introduced into the mixer in a content 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 hydrocarbon mix 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% by weight, relative to the weight of the mix after drying; b) implementation of the cold hydrocarbon mix directly at the outlet of the mixer of the self-propelled machine to form a layer having a thickness of at least 2 cm;c) then compacting the layer implemented during step b) to form the road surfacing layer.;

[0049] Advantageously, the cationic hydrocarbon binder emulsion comprises as emulsifier at least one amine, the amine representing at least 50% by weight of the total weight of the emulsifiers.

[0050] In particular, the amine is chosen from:

[0051] - alkylpolyamines, including alkyldiamines;

[0052] - fatty amines;

[0053] - amidopolyamines;

[0054] - fatty chain quaternary ammoniums;

[0055] - and their combinations.

[0056] In a preferred embodiment, the cationic hydrocarbon binder emulsion comprises as emulsifiers: (1) at least one alkylpolyamine, comprising one or two radicals chosen from a saturated or unsaturated hydrocarbon residue, comprising from 8 to 24 carbon atoms and / or its immediate cyclization derivatives as well as its oxyethylated or oxypropylated derivatives; and

[0057] (2) at least one amidopolyamine of formula (IV) Ri'CO-(NH-Ri") a -NH2, Ri' being a hydrocarbon residue, saturated or unsaturated, comprising from 12 to 24 carbon atoms, Ri" an ethylene radical, has an integer ranging 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 comprises a fatty acid dope or fatty acid derivative.

[0058] Cold-mixed asphalt is advantageously chosen from emulsion gravels or emulsion bituminous concretes.

[0059] The mineral solid fraction advantageously meets one or more of the following characteristics:

[0060] - the passage 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;

[0061] - the passage at 16 mm of the solid mineral fraction is 100% by weight, relative to the weight of the dry solid mineral fraction;

[0062] - the passage at 2 mm of the solid mineral fraction varies from 30% to 50% by weight, relative to the weight of the dry solid mineral fraction;

[0063] - the 2 mm passage of the solid mineral fraction varies from 20% to 40% by weight, relative to the weight of the dry solid mineral fraction.

[0064] The mineral solid fraction advantageously constitutes 94% to 96.5% by weight, advantageously 94% to 95.5% by weight, of the weight of the coating.

[0065] Advantageously, the coating does not include gum. In the process, during step a), water is introduced into the mixer in a content such that the total water is advantageously between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction.

[0066] The method may comprise a step prior to step a) of humidifying the mineral solid fraction.

[0067] The road surfacing 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 layer, a resurfacing or a reprofiling.

[0068] The self-propelled machine advantageously includes, in addition to the mixer:

[0069] - a hopper for feeding solid mineral particles;

[0070] - an emulsion tank;

[0071] - a smoothing sled or a finisher;

[0072] - a water tank;

[0073] - optionally a hopper for powder, such as lime or cement, and / or a lime milk tank;

[0074] - optionally a fiber dosing system.

[0075] DESCRIPTION OF FIGURES

[0076] Figure 1: Self-propelled machine mounted on a semi-trailer comprising: 1: an emulsion tank; 2: a water tank; 3: an aggregate hopper; 4: a powder hopper; 5: a mixer; 6: a sled.

[0077] DETAILED DESCRIPTION OF THE INVENTION:

[0078] It has been demonstrated that the manufacture and implementation of a cold hydrocarbon coating using a self-propelled machine equipped with a mixer makes it possible to obtain a road surfacing product with a good coating, fluidity and workability adapted to manufacture in a specific self-propelled machine and an increase in cohesion allowing rapid return to traffic, in particular in less than an hour, more advantageously in less than 30 minutes.

[0079] The cold-mixed hydrocarbon mixes obtained by this process have a good quality coating (at least equivalent to that observed for hot-mixed hydrocarbon mixes) without the drawbacks observed with the prior art processes, in particular because they are manufactured in situ and then implemented. Adapting the water content of the cationic emulsion of hydrocarbon binder makes it possible to regulate the coating and the rheology (fluidity) of the mix during application. The surfactants used allow a good coating, sufficient workability time and rapid cohesion recovery kinetics. As described below, it may be advantageous to add a mineral additive such as cement or a calcium or calcium-magnesium slurry. In addition, no heating or reheating step is necessary to adapt the workability of the mix or to hydrophobicize part of the aggregates.The cold hydrocarbon coatings obtained by the process according to the invention therefore meet 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.

[0080] Thus, the subject of the invention is a method for manufacturing a road surfacing layer based on cold hydrocarbon mix, comprising the following steps: a) coating at room 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 hydrocarbon mix, water is introduced into the mixer in a content 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 content of conventional residual anhydrous binder as described in standard NF P 98-139:2016-12 varies from 3.5 to 6% by weight, relative to the weight of the mix after drying;b) implementation of the cold hydrocarbon coating 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 implemented during step b) to form the road surfacing layer.;

[0081] The process is therefore characterized in that the hydrocarbon mix is ​​prepared in a mixer directly on site, in situ. Unlike the hydrocarbon mixes described in the aforementioned guide, the hydrocarbon mix is ​​not previously prepared in the factory. Step a) is therefore carried out on site.

[0082] The term “room temperature” defines a temperature ranging from 10°C to 40°C, preferably from 15°C to 35°C.

[0083] The terms “coated” and “hydrocarbon coated” are used interchangeably to designate the cold hydrocarbon coated obtained following step a) of the process according to the invention.

[0084] The term "ppc" means part per cent by weight. The quantities are expressed relative to the weight of the dry solid mineral fraction. For the binder content, the NF P 98-139:2016-12 standard requires the conventional residual anhydrous binder content to be mentioned, expressed as a percentage by weight relative to the weight of the asphalt mix after drying.

[0085] Once the process is initiated, steps a), b) and c) are most often carried out simultaneously.

[0086] Advantageously, the process does not involve sequencing. Advantageously, the process does not involve pre-coating, in particular sand and / or gravel.

[0087] Thus, advantageously, the mineral solid fraction added in step a) constitutes the entire mineral solid fraction of the cold-mixed hydrocarbon mix. Advantageously, the mineral solid fraction is not preheated, including partially.

[0088] Thus, advantageously, if a fluxing agent is added, its addition is not sequenced. Advantageously, no fluxing agent is added.

[0089] The total water in the composition of the cold asphalt mix plays a determining role in regulating the rheology, fluidity and coating of the composition during manufacture and implementation.

[0090] In 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 in step a), water is introduced into the mixer in a content such that the total water is between 10 ppc and 12 ppc relative to the weight of the dry solid mineral fraction.

[0091] The coating includes the following constituents:

[0092] - a hydrocarbon binder in the form of a cationic emulsion;

[0093] - a mineral solid fraction;

[0094] - supply water;

[0095] - possibly one or more additive(s).

[0096] Thus, during step a), a hydrocarbon binder in the form of a cationic emulsion, a mineral solid fraction, additional water, and possibly one or more additives are added to the mixer. These constituents are mixed during step a), the emulsion breaks and the hydrocarbon binder coats the mineral solid fraction to form a hydrocarbon coating. The process according to the invention allows good coating of the mineral solid fraction, including the largest elements.

[0097] The other constituents are then the constituents usually used. Advantageously, the hydrocarbon coating does not include synthetic, natural or modified natural rubber. In particular, the coating prepared in step a) is advantageously chosen from emulsion gravels or emulsion bituminous concretes. The coating prepared in step a) thus advantageously meets the definitions of standards NF P 98-139:2016-12 or NF P 98-121:2014-10.

[0098] Hydrocarbon binder:

[0099] The term "binder" means any hydrocarbon binder of fossil or plant origin that can be used to make 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 synthetic binder and / or a plant binder.

[0100] 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 a grade equal to or greater than 50 / 70, more advantageously binders of grade 50 / 70, 70 / 100, 100 / 150 or 160 / 220.

[0101] The binder may include additives commonly used in the road sector, such as crosslinked or non-crosslinked polymers (EVA, SBS, SB), rubber crumb, vegetable or petrochemical waxes without including synthetic, natural or modified natural gums, adhesion dopes.

[0102] The binder advantageously comprises a fatty acid dope, facilitating rapid recovery of cohesion. The fatty acid dope can be any fatty acid and derivatives, suitable for use in a bituminous material.

[0103] 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.

[0104] Fatty acids can be of fossil, animal, vegetable, or synthetic origin. They may have undergone chemical functionalization. Animal origin means, for example, tallow. Vegetable origin means vegetable oils; these are advantageously chosen from sunflower, soybean, rapeseed, linseed, coconut, peanut, olive, corn, castor oil, their derivatives, and their mixtures. These fats can also come from used oils from industry (food industry, paper industry, etc.).

[0105] By "fatty acid derivatives" we mean polymerized fatty acids.

[0106] Polymerized fatty acids include diacids or triacids of fatty acids or polyesters obtained by polymerization of a hydroxy acid.

[0107] By fatty acid diacid or triacid is meant 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.

[0108] The fatty acids can be chemically functionalized and thus carry at least one chemical function chosen from 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 having 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 makes it possible to obtain diacids or triacids linking the fatty acids by oxygen bridges formed on their hydrocarbon chains.

[0109] Preferably, the fatty acid is selected from the group consisting of oleic acid, linoleic acid, linolenic acid, and mixtures thereof.

[0110] The molecular mass of the diacid or triacid of fatty acids will preferably be between 600 and 800 g / mol.

[0111] We can cite, without limitation:

[0112] - oleic fatty acids, such as RADIACID® 208 available from the company OLEON;

[0113] - fatty acids from sunflower, copra (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;

[0114] - tallow fatty acids, such as RADIACID® 401 and RADIACID® 403;

[0115] - hydrogenated tallow fatty acids such as RADIACID® 408 and RADIACID® 409. These fatty acids can also be in the form of dimers or trimers, such as RADIACID® 0951.

[0116] The hydroxy acid is advantageously a hydroxy acid of formula (I)

[0117] HO-C(O)-Ra-CRb(OH)-Rc (I) where

[0118] Ra is a C8-C20, saturated or unsaturated, optionally branched, aliphatic hydrocarbon chain, optionally comprising one or more oxygen atoms, comprising a linear main chain of at least 8 carbon atoms;

[0119] Rb, Rc each represent, independently of each other, H or an aliphatic hydrocarbon chain, C1-C10.

[0120] Advantageously, Ra meets one or more of the following characteristics, advantageously all of the following characteristics:

[0121] - Ra is a linear hydrocarbon chain

[0122] - Ra is a hydrocarbon chain that can be saturated or unsaturated.

[0123] The unsaturation, when present, is advantageously a C=C double bond or a C=C triple bond, more preferably a C=C double bond. In one embodiment, Ra is a hydrocarbon chain which comprises 0 to 3 C=C double bonds, advantageously 0 to 2 C=C double bonds, more preferably 0 or 1 C=C double bond;

[0124] - Ra is a Cg-Ci5 hydrocarbon chain, more advantageously C10-C15.

[0125] In addition, Ra may comprise one or more oxygen atoms either interrupting the chain (ether functions) or pendant in the form of hydroxyl or ether functions in C1-C8. Advantageously, Rb represents H or a saturated, linear, aliphatic hydrocarbon chain, more advantageously in C1-C4. More advantageously, Rb represents H.

[0126] Advantageously, Rc represents a linear, saturated or unsaturated, aliphatic 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 which comprises 0 or 1 C=C double bond. Advantageously, Rc is a C4-C8 chain. Rc may comprise one or more oxygen atoms either interrupting the chain (ether functions) or pendant in the form of C1-C6 hydroxyl or ether functions.

[0127] A hydroxy acid of formula (I) can be homopolymerized or several hydroxy acids of formula (I) can be copolymerized. In addition, the polymerization reaction can be carried out in the presence of non-hydroxylated fatty acids, in particular saturated or unsaturated olefinic fatty acids comprising from 8 to 30 carbon atoms, optionally substituted by a C1-C4 alkyl radical. Examples that may be mentioned are oleic acid, palmitic acid, stearic acid, linoleic acid, 2-ethylhexanoic acid, etc. At least one hydroxy acid of formula (I) can also be copolymerized, optionally in the presence of non-hydroxylated fatty acids, with a dicarboxylic acid.

[0128] The hydroxy acid is advantageously chosen from ricinoleic acid, 12-hydroxystearic acid and combinations thereof.

[0129] The fatty acid dope can be added to the binder in a mixture with the polymers added to the binder or in-line.

[0130] 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.

[0131] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 6% by weight, relative to the weight of the asphalt after drying. The binder includes the binder introduced as such (contribution binder) and the binder recovered from the asphalt aggregates forming part, where appropriate, of the solid mineral fraction.

[0132] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 5.5% by weight, 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.

[0133] The conventional residual anhydrous binder content, as described in standard NF P 98-139:2016-12, is advantageously 3.5% to 6% by weight, 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.

[0134] 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 the asphalt, advantageously from 4.5% to 5.5% or 6%, depending on the aggregate content of the asphalt, by weight relative to the total weight of the asphalt after drying for emulsion bituminous concretes or advantageously from 3.5% to 4.5% or 6%, depending on the aggregate content of the asphalt, by weight relative to the weight of the asphalt after drying for a gravel-emulsion.

[0135] 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 comprising at least one cationic emulsifier.

[0136] The content of emulsifying composition 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 content of emulsifying composition 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.

[0137] In an advantageous embodiment, the emulsifying composition mainly comprises at least one amine. For the purposes of the present invention, the term “mainly” 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 chosen from:

[0138] - alkylpolyamines, including alkyldiamines;

[0139] - fatty amines;

[0140] - amidopolyamines;

[0141] - fatty chain quaternary ammoniums;

[0142] - and their combinations.

[0143] The 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.

[0144] Alkylpolyamines advantageously correspond to formula (II):

[0145] NRIR2- R3-(NR4-R5)X-NR6R7 (II) in which:

[0146] - x is an integer ranging from 0 to 3. Advantageously x is 0;

[0147] - one or two of Ri, R2, Rs, R7, represents a hydrocarbon radical comprising from 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;

[0148] - the others of Ri, R2, Rs, R7, each represent, independently of one another: 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-CRgOH) z -H in which Rg is a hydrogen atom or a methyl radical, z is 1 or 2. Advantageously the others of Ri, R2, Rs, R7, represent a methyl or ethyl radical;

[0149] - R3 represents a hydrocarbon radical comprising from 1 to 6 carbon atoms, saturated or unsaturated, linear or branched. Advantageously R3 represents an ethylene or propylene radical;

[0150] - R4, Rs each represents, independently of one another: 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- CRgOH) z -H in which Rg is a hydrogen atom or a methyl radical, z is 1 or 2. Advantageously R4, Rs represents a methyl or ethyl radical.

[0151] An example is tallow trimethylpropylene diamine.

[0152] Fatty amines advantageously correspond to the formula (III): NR9R10- R11 (III) in which

[0153] - Rg represents a hydrocarbon radical comprising from 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;

[0154] - 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-CRgOH) z -H in which Rg is a hydrogen atom or a methyl radical, z is 1 or 2. Advantageously Rio represents a methyl or ethyl radical; - Ru represents a hydrocarbon radical comprising from 1 to 6 carbon atoms, saturated or unsaturated, linear or branched. Advantageously Rn represents a methyl, ethyl or propyl radical.

[0155] An example is tallow dimethylamine.

[0156] The amidopolyamines advantageously correspond to the formula (IV)

[0157] Ri'CO-(NH-Ri") a -NH2(IV) in which:

[0158] - R is a saturated or unsaturated, linear or branched hydrocarbon residue comprising from 12 to 24 carbon atoms, advantageously 16 to 24 carbon atoms. This radical is advantageously derived from tall oil or tallow fatty acids;

[0159] - Ri" is an ethylene radical;

[0160] - a represents an integer ranging from 2 to 5, preferably a is 5; and / or its immediate cyclization derivatives, in particular imidazoline derivatives.

[0161] The 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.

[0162] Quaternary ammoniums can in particular be of formula (V)

[0163] (Rx) b N + (Ry) c Y- (V) in which:

[0164] - Rx represents a hydrocarbon radical comprising from 8 to 24 carbon atoms, more advantageously 12 to 22 carbon atoms, saturated or unsaturated, linear or branched, optionally cyclized;

[0165] - Ry represents an alkyl radical comprising from 1 to 6 carbon atoms, optionally hydroxylated, in particular methyl, ethyl, propyl, hydroxyethyl, hydroxypropyl; - Y" denotes an anion of a mineral acid, in particular a chloride anion, or of an organic acid, in particular an acetate or formate anion;

[0166] - c is an integer equal to (4-b) and

[0167] - b can take the values ​​of 1, 2 or 3.

[0168] Among the surfactants relevant for this application we can mention the following commercial products:

[0169] - Dinoram®S (Ceca) or Redicote®E9 (Akzo Nobel): N alkyl tallow propylene diamine;

[0170] - Emulsamine®L 60 (Ceca): Preparation based on tall oil fatty amide, N-(3-dimethylamino)propyls (> 50%) and Emulsamine®LZ (> 25%) with an aromatic hydrocarbon (> 1%) and diethanolamine (> 1%);

[0171] - Polyram®S (Ceca): N-alkyl tallow propylene polyamine with Dinoram®S (< 10%), tallow alkyl amines (Noram®S - < 5%), tallow nitrile (< 10%);

[0172] - Stabiram®MS 601 (Ceca): solution of N-alkyl tallow N-dimethyl amino propyl N-trimethyl ammonium dichloride (> 50%) in a water / hexylene glycol mixture (glycol > 20%) with Dinoram®S (< 1%);

[0173] - Dinoram®O (Ceca): N-(C16 and C18 alkyl unsaturated) trimethylene diamine (oleic diamine);

[0174] - Emulsamine®640 (Ceca): Preparation based on tall oil fatty amides (> 50%), Dinoram®O (> 25%) and (Z)-octadec-9-enylamine (> 1%);

[0175] - Indulin® R 66 (Meadwestvaco): Tall oil fatty amides: N - [(dimethylamino)-3-propyl];

[0176] - Indulin® R 33 (Meadwestvaco): Tall oil fatty amides (N-[(dimethylamino)-3-propyl]) (75-90%), N-tallow alkyltrimethylenediamine (20-25%);

[0177] - lndulin®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%);

[0178] - lndulin®GE F2 (Meadwestvaco): C12-C14 ethoxylated alcohols (2.5-25%), alkali lignin (reaction produced with dimethylamine and formaldehyde) (10-20%), N-(C14-18 alkyl and C16-18 unsaturated)-trimethylenediamine (1-3%); - Duomeen®TTM (Akzo Nobel): tallowtrimethylpropylenediamine (90-100%), tallowdimethylamine (5-10%);

[0179] - Redicote®404 (Akzo Nobel): tall oil, reaction products with tetraethylenepentamine (100%).

[0180] One or more of these surfactants can be used, alone or in mixtures.

[0181] 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 cationic hydrocarbon binder emulsion comprises, as emulsifiers:

[0182] (1) at least one alkylpolyamine as defined above, in particular trimethylpropylene diamine tallow;

[0183] (2) at least one amidopolyamine as defined above and / or its immediate cyclization derivatives;

[0184] (3) optionally a fatty amine as defined previously.

[0185] In this variant, the binder advantageously comprises a fatty acid dope as described above.

[0186] 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 able to be of the nonylphenol-, octylphenol-, cetyl, oleic, etc. type, the hydrophilic part being made up of several ethoxy groups.

[0187] Acid

[0188] 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 makes it possible to ionize the cationic functions, in particular amines, of the emulsifiers to allow their dissolution in water. 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.

[0189] The acid is advantageously hydrochloric acid, phosphoric acid or a polyphosphoric acid. Polyphosphoric acid is an oligomer of phosphoric acid comprising molecules according to either of the structural formulas P n O3n+i (n+2)_in which n is an integer greater than or equal to 1, advantageously 1, 2 or 3, or P2O5*x(O 2 ), in which x is between 0 and 1.

[0190] 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.

[0191] Solid mineral fraction:

[0192] By "solid mineral fraction", or "solid mineral fraction", these two expressions being used interchangeably, is meant in this description 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 surplus from asphalt plants, schists in particular bauxite or corundum, rubber crumb and their mixtures in all proportions.

[0193] "Asphalt aggregates" means asphalt (mixture of aggregates and bituminous binders) from milling asphalt layers, crushing of slabs extracted from asphalt pavements, pieces of asphalt slabs, asphalt waste or surplus asphalt production (surplus production is material coated or partially coated in the plant resulting from transitional manufacturing phases). These elements and other recycled products can reach dimensions of up to 14 mm.

[0194] The particle size of the mineral fraction, in particular mineral aggregates, is measured by the tests described in standard NF EN 933-2 (July 2020 version).

[0195] The “mineral solid fraction” is also referred to as the “0 / D mineral fraction”. This 0 / D mineral fraction can be separated into two particle sizes: the 0 / d mineral fraction and the d / D mineral fraction.

[0196] The finest elements (the mineral fraction 0 / d) will be those included in the range between 0 mm and 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.

[0197] Advantageously, the mineral solid fraction comprises:

[0198] - elements less than 0.063 mm (filler or fines);

[0199] - elements, in particular sand, having a size between 0.063 mm and 2 mm;

[0200] - elements, in particular gravel, having a size:

[0201] - - between 2 mm and 6 mm;

[0202] - - between 6 mm and 14 mm.

[0203] Advantageously, the size of the solid mineral fraction at 0.063 mm 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.

[0204] Advantageously, the 16 mm pass of the solid mineral fraction is 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. Advantageously, in particular for grave-emulsions, the 2 mm pass of the solid mineral 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.

[0205] Advantageously, in particular for bituminous emulsion concretes, the 2 mm pass of the solid mineral 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.

[0206] In one variant, the mineral solid fraction comprises less than 30% by weight, relative to the weight of the dry solid mineral fraction, of coated aggregates.

[0207] In another variant, the mineral solid fraction comprises at least 30% by weight, relative to the weight of the dry solid mineral fraction, of asphalt aggregates. The mineral solid fraction advantageously comprises up to 75% by weight, relative to the weight of the dry solid mineral fraction, of asphalt aggregates.

[0208] Generally, 0 / 4, 0 / 6, 0 / 6 discontinuous, 0 / 8, 0 / 8 discontinuous or 0 / 10 recomposed granulometries are used, with possible humidification to avoid segregation during transport.

[0209] The solid mineral fraction advantageously constitutes 94% to 96.5% by weight, advantageously 94% to 95.5% by weight, of the weight of the coating.

[0210] The process advantageously comprises a step prior to step a) of humidification of the mineral solid fraction.

[0211] 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 breaking quality of the emulsion and improve the adhesive properties. This additive can be cement, lime, calcium lime milk, or a calcium-magnesium milk.

[0212] 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 hydration reactions and processes and which, after hardening, retains its strength and stability even under water (standards NF P98-149 (2000-06-01)).

[0213] 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.

[0214] 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.

[0215] In the variant of the invention, in which the emulsifying composition comprises at least one alkylpolyamine and at least one amidopolyamine, a calcium-magnesium slurry is advantageously added to the solid mineral fraction of the cement.

[0216] A retarding agent can also be added to the solid mineral fraction to regulate the workability time of the cold-mixed asphalt. This retarding agent is a cationic surfactant or other cationic compound dispersible or dilutable in water which has a delaying action on the setting of the material.

[0217] Fibers such as glass fibers or polyacrylonitrile fibers, advantageously fibers of 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 (part per cent by weight) / dry aggregates, preferably between 0.07 ppc and 0.2 ppc. The mineral fraction described here is that added in step a) of the process. The process advantageously comprises a step prior to step a) of humidifying the solid mineral fraction.

[0218] Others :

[0219] The emulsion may contain synthetic or natural latex. Latex is a dispersion of polymers (styrene-butadiene, also known as SBR for "styrene butadiene rubber" in English, acrylic or styrene-acrylic) crosslinked or not in aqueous phase. This latex is incorporated into the aqueous phase before emulsification or in-line during the manufacture of the emulsion or even after the manufacture of the emulsion.

[0220] Although this is not a preferred variant, fluxes of petroleum origin or from agricultural resources can also be added. These fluxes can be added during the production of the emulsion or during step a) of the process.

[0221] The fluxing agent is advantageously a flux of petroleum or petrochemical origin. A petroleum flux is a product resulting from the distillation of crude oil (light fraction(s)), which may have undergone a hydrotreatment 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®).

[0222] The fluxing agent is advantageously a flux of natural, non-fossil origin (plant or animal origin). A flux 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.

[0223] Preferably, vegetable oils such as sunflower, rapeseed, peanut, copra, linseed, palm, soybean, olive, castor, corn, pumpkin, grape seed, jojoba, sesame, walnut, hazelnut, tungsten wood, tall oil, their derivatives, as well as their combinations will be used. In particular, the flux of natural, non-fossil origin is chosen from the group consisting of:

[0224] - esters, in particular monoesters including methyl monoesters, or amides, optionally functionalized by oxidation, obtained from vegetable or animal oils (pine oil, sunflower oil, rapeseed oil, linseed oil, castor oil, peanut oil, copra oil, olive oil, palm oil, cotton oil, corn oil, tallow oil, lard oil, palm kernel oil, soybean oil, pumpkin oil, grape seed oil, jojoba oil, sesame oil, walnut oil, hazelnut oil, tungsten carbide oil, 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 combinations thereof;

[0225] - heavy oils of mineral origin, animal and vegetable oils and fats, and their derivatives functionalized with transesterification products and saponification products and their combinations (as described in application AT 406 375); and their combinations.

[0226] A drying additive, such as manganese octoate, may be added to these oils and derivatives to promote oxidation reactions.

[0227] Advantageously, as already mentioned, no synthetic, natural or modified natural gum is added, in particular gum as described in application FR 2 927 328 or EP 2 090 620.

[0228] In step a), all the constituents described above are mixed in the mixer of the self-propelled machine to form a hydrocarbon coating.

[0229] In step a), the mixture can be kneaded without breaking the emulsion, advantageously for a few tens of seconds, preferably for at least 90 seconds.

[0230] In step a), the emulsion breaks well. The quality of breakage can be examined in the laboratory, by measuring the breaking time of the emulsion considered with the solid mineral fraction. The breaking time, also called setting time, corresponds to the time required for the hydrocarbon binder emulsion to be completely broken after contact with the solid mineral particles. A sample of the mix is ​​placed in a glass of colorless water, at different times, after its workability has decreased. If the water becomes colored, 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, the more significant this phenomenon is. There is a scale from 0 to 5 allowing these color indices to be compared.

[0231] In the context 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 solid mineral particles.

[0232] The self-propelled machine combines the functions of dosing, mixing and implementing the mixture.

[0233] Advantageously, the self-propelled machine includes, in addition to the mixer:

[0234] - a hopper for feeding solid mineral particles;

[0235] - an emulsion tank;

[0236] - a smoothing sled or a finisher;

[0237] - a water tank;

[0238] - optionally a hopper for powder, such as lime or cement, and / or a tank of lime milk or calcium-magnesium milk;

[0239] - optionally a fiber dosing system;

[0240] - optionally an additive tank.

[0241] The equipment is usually mounted on a tractor or semi-trailer. A self-propelled machine that can be used is shown in Figure 1.

[0242] The solid mineral fraction is loaded into the aggregate hopper. It is then conveyed to the mixer, advantageously by an extractor belt whose speed can vary depending on the forward speed of the machine on site. A weighing system for the solid mineral fraction can be provided. The capacity of the aggregate hopper advantageously varies from 4 m 3 at 16 m 3 , advantageously 5 m 3 at 14 m 3 .

[0243] The cationic hydrocarbon binder emulsion is stored in the emulsion tank, the capacity of which advantageously varies from 1 m 3 at 10 m 3 , advantageously 4 m 3 at 8 m 3. Advantageously, a volumetric pump is used to feed the mixer with emulsion. The feed dosage is advantageously adjusted according to the machine's forward speed on site and the feed rate of solid mineral fraction into the mixer.

[0244] The amount of water stored in the water tank advantageously varies from 1 m 3 at 8 m 3 , advantageously 4 m 3 at 8 m 3 .

[0245] The mixer is advantageously a continuous mixer with two parallel shafts. The number of blades on the two shafts varies from 20 to 80 blades, advantageously from 32 to 60 blades. The rotation speed of the screws varies from 200 to 800 rpm, advantageously from 300 to 600 rpm.

[0246] The length of the mixer advantageously varies from 100cm to 200cm and advantageously from 130 to 150cm.

[0247] Any application sled can be used. The sled, also called a table, can include one or more joints to adapt to the profile of the surface on which the coatings will be applied. A paver can also be used.

[0248] The machine advantageously comprises at least one servo-control system making it possible to keep the proportions of the constituents of the asphalt mix constant during step a) of the process and / or step b) of the process. The adjustments in water and possibly in additive(s) can advantageously be carried out from a control panel.

[0249] In step b), the cold asphalt mix, directly from the mixer of the self-propelled machine, is used to form a layer having a thickness of at least 2 cm. The thickness of this layer can advantageously be up to 5 cm. This layer is then compacted during step c) of the process.

[0250] Once the work has started, steps a) and b), or even c), are generally simultaneous.

[0251] The compacted road surfacing layer advantageously has a thickness ranging from 1.5 cm to 8 cm, advantageously between 2 cm and 5 cm. The road surfacing layer is advantageously chosen from a wearing course having a thickness varying from 1.5 cm to 3 cm, advantageously from 2 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 layer, a resurfacing or a reprofiling. The thickness here corresponds to the thickness of the layer after compaction, therefore after step c).

[0252] Emulsion asphalt concretes are advantageously used as a wearing course. Thus, emulsion asphalt concretes must withstand the aggression of traffic and bad weather throughout their service life. Emulsion asphalt concretes advantageously have a thickness, after step c) of the process, of between 1.5 cm and 8 cm, in particular between 2 cm and 3 cm or between 3 cm and 5 cm or between 5 cm and 8 cm. Emulsion asphalt concretes have a void content, measured according to the modified Duriez Test (NF P 98-251-4, compaction method no. 1) of less than or equal to 15%.

[0253] The following are commonly used:

[0254] - in maintenance work on an existing roadway for reprofiling work, localized repairs;

[0255] - in new construction: for base layers or bonding layers;

[0256] - in general reloading or reinforcement.

[0257] They are then normally covered with at least one wearing course. The emulsion gravel advantageously has a thickness, after step c) of the process, of between 1 cm and 15 cm. The thickness is adapted according to the use.

[0258] Production rates vary advantageously from 30 tonnes to 150 tonnes of asphalt / hour, more advantageously from 70 to 120 tonnes of asphalt / hour.

[0259] The method according to the invention allows good coating of the mineral solid fraction, including the largest elements. In particular, more than 90% of the surface of the mineral solid fraction is coated. More particularly, more than 97% of the surface of the mineral solid fraction is coated. Even more particularly, 100% of the surface of the mineral solid fraction is coated, i.e. no surface of the mineral solid fraction is uncovered.

[0260] The coating quality after 24 hours of curing is advantageously at least class E2 for a hydrocarbon coating 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.

[0261] The color index at 10 min of the coating obtained by the process according to the invention is advantageously less than 2, even more advantageously less than 1.

[0262] The color index makes it possible to evaluate the breaking state of the bitumen emulsion in contact with the solid mineral fractions after a resting time of 10 minutes. The test carried out consists of taking a mass of asphalt (approximately 10 grams) 10 minutes after the manufacture of the asphalt and then introducing this mass of asphalt into a volume of 100 ml of clear water. The coloring of the water in contact with the mass of asphalt provides information on the breaking state of the emulsion. This coloring is rated from 0 to 5, the coloring score 0 corresponding to clear water synonymous with complete breaking of the emulsion and the coloring score 5 corresponding to water strongly colored black synonymous with no breaking of the emulsion. The cohesion time of the asphalt 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 minutes.

[0263] The cohesion time corresponds to the time required for the cold asphalt mix to develop strong cohesion. The test carried out is sensory and is carried out by handling the cold asphalt mix at different curing times at room temperature.

[0264] The method according to the invention also allows satisfactory workability of the coating.

[0265] Workability time, also called fluidity or consolidation time: time determined as the duration between (1) the start of mixing of the solid mineral fraction and the bitumen emulsion (start of step a)) and (2) the setting of the cold hydrocarbon mix (after step c)). In order to evaluate the workability time of a cold hydrocarbon mix, to ensure implementation by the application machine, laboratory tests are carried out in a container on batches of 400 g to 1000 g of dry materials. After mixing the constituents, the change in state of the cold hydrocarbon mix (transition from liquid to pasty state) is assessed by stirring manually using a spatula at constant speed (approximately l revolution / s). The change in state observed gives the setting time.

[0266] 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.

[0267] The cold hydrocarbon mixes obtained by the process according to the invention advantageously meet the requirements mentioned in the IDRRIM guide “Factory-made emulsion mixes” and / or in standards NF P 98-121 and NF P 98-139 depending on the nature of the mix formulated, in particular the compactability, compressive strength and water resistance.

[0268] Compactionability defines the ability of cold-mix asphalt to achieve a set void content under defined conditions. Compactionability is measured using 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 maintained at a set temperature. Compaction is achieved by combining gyratory shear and a resulting axial force applied by a mechanical head. This method makes it possible to determine the change in the percentage of voids in the specimen as a function of the number of gyrations.

[0269] Compressive strength and water resistance are measured according to standard NF P98-251-4. The purpose of this method is 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 the compressive strengths with and without immersion of the test pieces.

[0270] The rigidity modulus is measured according to standard NF EN 12697-26 annex C, June 2018.

[0271] The method according to the invention makes it possible to prepare hydrocarbon coatings having the desired coating and having a sufficiently rapid increase in cohesion and hardening to allow rapid return to traffic, in particular in less than one hour, more advantageously in less than 30 minutes.

[0272] EXAMPLES:

[0273] Example 1: Cold asphalt mixes for wearing course (Emulsion Bituminous Concrete - BBE) 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 asphalt mixes”.

[0274] Different emulsions were first made: Table 1

[0275] Radiacid 166: anionic surfactant of rapeseed fatty acid

[0276] Indulin GE F2: cationic surfactant (mixture comprising ethoxylated alcohols, CAS: 68439-50-9; reaction products of lignin, dimethylamine and formaldehyde, CAS: 110152-58-4 and alkyl diamines, CAS: 68439-73-6) 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)

[0277] Redicote C320E: cationic surfactant (mixture comprising 60-70% tallow trimethylpropylene diamine, CAS: 68783-25-5 and 30-40% reaction products of tall oil with tetraethylenepentamine, CAS: 68555-22-6)

[0278] The contents in Table 1 are the commercial product contents. Hydrochloric acid is at a concentration of 37% and phosphoric acid at 85%.

[0279] These emulsions were made using a laboratory Atomix C mill.

[0280] From these bitumen emulsions, cold hydrocarbon coatings are prepared either by hand with a mass of 500g of material, or using a mixer from the company SR Consulting with parallel shafts for a mass of 25kg of material.

[0281] The tests were carried out on solid mineral particles of the dioritic type.

[0282] The solid mineral fraction comprises, by weight relative to the total weight of the dry mineral fraction:

[0283] - 30.0% sand by weight Dussac 0 / 2;

[0284] - 45.0 of Dussac 2 / 6 aggregates;

[0285] - 25.0 of Dussac 6 / 10 aggregates

[0286] The cut 0 / 2 corresponds to the fraction 0 / d.

[0287] The denominations 2 / 6 and 6 / 10 together form the fraction d / D.

[0288] This mineral fraction makes it possible to produce a 0 / 10 coating.

[0289] 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).

[0290] The characteristics of the prepared cold hydrocarbon mixes are given in the following table 2:

[0291] Table 2

[0292] *dried with 4% by mass of Octa soligen® Manganese 10 HS from the company

[0293] Borchers

[0294] The BBE RI cold mix asphalt is the reference mix manufactured using a sequencing method. The d / D aggregates are first coated with 1 / 3 of the total emulsion mass for 8 seconds, then the 0 / d sand moistened with the added water is introduced into the mix with the remaining 2 / 3 of the emulsion mass and the composition is mixed for 9 seconds. At the end of mixing, the fluxing agent is added to the composition under agitation and then the mix is ​​mixed for a further 3 seconds.

[0295] The cold-mixed asphalt mixes BBE 11, BBE 12 and BBE 13 are mixes according to the invention. The entire mineral solid fraction (0 / D) is moistened with the added water, then the entire emulsion is added to the mineral solid fraction and then the composition (400-500g) is mixed vigorously for 15 seconds (5 rpm) to simulate the coating in the mixer of an application machine. The mixture is then mixed less vigorously (ltr / s) for up to 90 seconds to simulate the passage of the cold-mixed asphalt mix in the sled of the application machine.

[0296] The coating, workability time, breaking time or color index at 10 minutes, compactability (PCG) and compressive strength of these emulsion bituminous concretes according to the invention are evaluated. The cold asphalt mix is ​​also evaluated without considering the workability time and breaking time.

[0297] There are no existing tests to assess the cohesion of BBEs at early ages. Therefore, assessment of cohesion at 1h and 24h is generally done visually. In order to highlight the superior cohesion of the formulas of the invention, a simple test, called fracture test, was developed with the aim of providing quantitative values.

[0298] Three kilograms of asphalt are prepared by mixing the solid mineral fraction and the cationic bitumen emulsion for 20 seconds. The BBE RI is prepared by a sequenced coating process while the BBE 11, 12 and 13 are prepared by a direct coating process. For the sequenced coating process, the sequencing steps consist of mixing the d / D aggregates with a first part of emulsion (generally one third of the total mass of emulsion) for 8 seconds, then adding the 0 / d fraction with optionally the asphalt aggregates and the second part of emulsion (generally two thirds of the total mass of emulsion), mixing for 9 seconds, and finally adding the fluxing agent if necessary while mixing the mixture for up to 20 seconds of total mixing.

[0299] Four asphalt slabs measuring 120*120*20 mm are then prepared:

[0300] - in the case of BBE RI, the industrial process is adapted by leaving the asphalt expanded for 4 hours at 18°C, representing a significant transport time, then by decohesioning the asphalt pile, in order to simulate the passage of the asphalt in the paver screws, to prepare the test plates by compaction with a manual roller (6 passes) in order to reach 2 cm thickness. The plates then undergo curing at 18°C ​​and 55% humidity for 1 hour or 24 hours before carrying out the fracture test.

[0301] - in the case of BBE 11, 12 and 13, the asphalt is poured into the same molds but directly after mixing. A thickness of 2 cm is set without compaction this time. The slabs then undergo curing at 18°C ​​and 55% humidity for 1 hour or 24 hours before carrying out the fracture test.

[0302] After curing for 1 hour or 24 hours, the BBE plate is removed from the mold and placed on a flat surface with a hatch opening into the void. The plate is placed with a counterweight on its fixed part (part placed on the surface without the hatch) and half of the plate is placed in the void once the hatch is open. The time required for the plate to break after opening the hatch is then measured. The result is given in seconds and represents the fracture time. The longer the time, the more resistant the BBE is in bending and therefore the more advanced the increase in cohesion.

[0303] Cohesion is considered “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.

[0304] The results obtained are shown in the following table:

[0305] Table 3

[0306] * BBE type 2 TM specifications as defined in standard NF P 98-139:2016-12

[0307] The results presented in the table above demonstrate that it is possible to obtain a very good coating using the process according to the invention. It is also possible to obtain a workability time compatible with the production of a cold hydrocarbon coating in a self-propelled machine.

[0308] According to the method of the invention, the cold hydrocarbon mixes exhibit a significantly faster and stronger increase in cohesion than with a cold hydrocarbon mix produced according to the methodology known in the art. The minimum mechanical specifications required by standard NF P 98-139 are largely achieved. A clear increase in compressive strength is noted for the cold hydrocarbon mixes according to the invention compared to a mix produced according to the methodology known in the art.

Claims

DEMANDS 1. 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 content of conventional residual anhydrous binder as described in standard NF P 98-139:2016-12 varies from 3.5 to 6% by weight, 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 put in place during step b) to form the road surfacing layer.

2. A process according to claim 1, wherein the cationic emulsion of hydrocarbon binder 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 any one of the preceding claims, wherein the amine is selected from the group consisting of: - alkylpolyamines, including alkyl diamines; - fatty amines; - amidopolyamines; - quaternary ammonium compounds with fatty chains; - and their combinations.

4. A process according to any one of the preceding claims, wherein the cationic emulsion of hydrocarbon binder 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 12 to 24 carbon atoms, Ri" an ethylene radical, has an integer ranging 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 gravel or emulsion-bound bituminous concrete.

6. A method according to any one of the preceding claims, wherein the 0.063 mm passing of the mineral solid fraction varies from 4% to 10% by weight, relative to the weight of the dry solid mineral fraction.

7. A method according to any one of the preceding claims, wherein the 16 mm passing of the mineral solid fraction is 100% by weight, relative to the weight of the dry mineral solid fraction.

8. A method according to any one of the preceding claims, wherein the 2 mm passing of the mineral solid fraction varies from 30% to 50% by weight, relative to the weight of the dry mineral solid fraction.

9. A method according to any one of claims 1 to 7, wherein the 2 mm passing of the mineral solid fraction varies from 20% to 40% by weight, relative to the weight of the dry mineral solid 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 1.5 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 powdered materials, such as lime or cement, and / or a lime slurry tank; - optionally a fiber dosing system.

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