Additive for road materials

Abstract

The present invention relates to an additive composition for asphalt emulsion, comprising: - 20% to 80% by weight, relative to the total weight of the additive, of at least one C12-C22 monoacid comprising a linear or branched, saturated or unsaturated hydrocarbon chain; and - 20% to 80% by weight, relative to the total weight of the additive, of at least one C12-C22 monoacid dimer comprising an unsaturated, linear or branched hydrocarbon chain, the total weight of monoacid(s) and monoacid dimer(s) representing at least 70 wt.-% relative to the total weight of the additive.

Description

ROAD MATERIAL ADDITIVE

[0001] The present invention relates to an additive for a bituminous emulsion. The present invention also relates to a bituminous emulsion comprising bitumen, water, an emulsion, and said additive. The present invention further relates to a cold-applied asphalt mix composition comprising said bituminous emulsion and aggregate. The present invention also proposes a use for cold-applied asphalt mix in road construction applications.

[0002] In the road construction industry, road surfaces are of great importance and must meet a number of criteria. The surface must be easy to apply while also being resistant to wear and tear from time, weathering, and vehicle traffic.

[0003] Bituminous pavements are generally used to fulfill these functions. They are obtained by coating, which involves mixing bituminous binders with aggregates. These binders typically consist of the heaviest fraction recovered during the petroleum distillation process and products obtained from the extraction of tar and oil sands. The aggregates are generally divided mineral materials produced in quarries, such as asphalt pavement aggregates, milled asphalt, slag, clinker, and recycled concrete from demolition.

[0004] Several techniques for preparing bituminous road materials called asphalt mixes are well known to those in the trade.

[0005] Hot mix techniques use temperatures above 100°C (typically 150°C-170°C) allowing the necessary fluidization of an anhydrous bituminous binder for homogeneous mixing with aggregates to obtain so-called hot mix asphalt.

[0006] Warm techniques are similar to hot techniques but use temperatures 10°C to 40°C lower than hot techniques.

[0007] These so-called hot and warm techniques therefore require a heat input, resulting in additional energy costs. Furthermore, the preparation of bituminous materials at high temperatures generates fumes that are harmful to workers and local residents.

[0008] Cold techniques use lower temperatures than hot or warm techniques (typically 20°C to 60°C lower). These methods thus reduce, or even eliminate, the production of these fumes while minimizing the additional energy cost.

[0009] Cold-mix techniques involve combining an aqueous-phase bituminous emulsion with aggregates. Mixing the bituminous emulsion and aggregates just before application results in the formation of cold-mix asphalt (also called cold-mixed bituminous materials), while mixing these components in a storage plant produces stockpiled asphalt, emulsion-treated aggregate, and emulsion-treated asphalt concrete.

[0010] Cold-applied bituminous materials (CFBMs) are considered road materials as described in the information note from the Technical Studies Service for Roads and Highways (SETRA) of the Roads Directorate of the Ministry of Equipment (Information Note on Roads and Infrastructure No. 102 "Cold-Applied Asphalt" of June 1997), or in the guidelines published in May 2003 by the International Slurry Surfacing Association (Annapolis, MD, USA). CFBMs are understood here to encompass all variations of this technology.

[0011] Cold-mix asphalt (CMA) and emulsion-treated aggregates are defined respectively in standards NF P 98-139 and NF P 98-121. Storeable asphalt mixes are cold-mix asphalt mixes that can be stored for several weeks or months and are generally used for road maintenance.

[0012] Bituminous binder (or bituminous phase) is understood to mean natural bitumen, bitumens derived from mineral oil, bitumens derived from cracking, tar, blown bitumens, bitumens diluted with petroleum solvents, bitumens diluted with vegetable oils or any resulting mixture.

[0013] Bituminous emulsions are generally obtained by mixing a bituminous binder and at least one aqueous phase additive.

[0014] An emulsion is a mixture of a heterogeneous system composed of at least two immiscible liquids, in which fine droplets of one liquid are dispersed in the continuous phase of the other liquid. Thus, a bitumen emulsion is equivalent to the dispersion of a bituminous phase in an aqueous phase in the presence of at least one additive such as a surfactant, emulsifier, thickener, fluxing agent, plasticizer, or other additive that allows for adjustment of the emulsion.

[0015] Cold-laid asphalt mixes must possess a number of characteristics in order to be considered high-performing.

[0016] When implementing asphalt as a road surface in the form of a wearing course for the renovation or repair of roads, a good rise in cohesion corresponding to a satisfactory adhesion between bitumen and aggregate is necessary (with or without external stress) in order to allow the surface to withstand traffic.

[0017] This cohesion is achieved by compacting the material accompanied by the expulsion of the aqueous phase of the emulsion and air.

[0018] In summary, in the case of cold mix asphalt, applicators seek: good stability of the bituminous emulsion during the mixing of the asphalt allowing for correct laying, good coating of the aggregate by the bitumen in all stages of the process, good bitumen / aggregate adhesion properties as well as sufficient cohesion and rapid setting of the asphalt to allow a rapid opening to traffic without risking road degradation (tearing, cracking and others).

[0019] The additives in the bituminous emulsion play a key role in obtaining the desired characteristics of the final asphalt mix, and the simple use of surfactants does not allow these to be obtained.

[0020] It is known to those skilled in the art that the use of fatty acids in the form of polymerized fatty acids or polymers containing a carboxylic acid function as additives (also called dopes) improves bitumen / aggregate adhesion and / or the increase in cohesion.

[0021] Polymerized fatty acids are acids resulting from the polymerization of chains of at least two unsaturated fatty acids possessing 12 to 22 carbon atoms.

[0022] Document FR2930253 describes a bituminous emulsion comprising one or more polymerized fatty acids, preferably in the form of fatty acid dimers or trimers for a cold-mix asphalt.

[0023] Document FR3017385 describes a cationic bituminous emulsion of bitumen comprising at least one alkylpropylene polyamine, phosphoric acid (a specific surfactant / mineral acid pair), and a fatty acid doping agent. The fatty acids considered are, in particular, fatty acid dimers or trimers. This bituminous emulsion is used for the preparation of a cold-applied bituminous material.

[0024] Document EP0416682 relates to a bitumen composition comprising at least one polymerized fatty acid and its use in bituminous emulsions or surface coatings.

[0025] US2632712 document relates to bituminous compositions comprising a polymerized unsaturated fatty acid for road construction.

[0026] Document EP0227238 proposes a bituminous composition comprising a fatty acid (with a chain of C to C30) such as stearic acid, palmitic acid or oleic acid.

[0027] Document W02020193692 describes a cationic bitumen emulsion comprising an additive corresponding to a thermoplastic polymer having at least one carboxylic acid function.

[0028] However, it is necessary to offer additives for bituminous emulsion that are easy to handle, typically pumpable, and increasingly efficient, enabling the desired characteristics of the final cold-poured bituminous mix to be obtained.

[0029] The inventors discovered that a particular blend of fatty acids had a viscosity that made the mixture pumpable, thus facilitating its industrial use. Furthermore, the inventors demonstrated that this specific additive maintains a sufficiently long emulsion stability time, allowing for easy mixing during asphalt application (breaking time). In addition, this additive contributes to improving the cohesion development of cold-applied asphalt. Brief description of the invention

[0030] The present invention relates to an additive for bituminous emulsion comprising -from 20% to 80% by weight relative to the total weight of the additive of at least one monoacid in the C12-C22 range, inclusive, comprising a hydrocarbon chain, linear or branched, saturated or unsaturated and -from 20% to 80% by weight relative to the total weight of the additive of at least one dimer of monoacid(s) in C12-C22, inclusive, comprising a linear or branched, unsaturated hydrocarbon chain, the total weight of monoacid(s) and monoacid(s) dimer(s) representing at least 70% by weight, preferably at least 80% by weight, preferably still at least 90% by weight, relative to the total weight of the additive.

[0031] The invention also relates to the use of the additive for preparing a bituminous emulsion. The present invention also relates to a bituminous emulsion comprising bitumen and an aqueous phase, including the additive according to the invention. The present invention also relates to a method for preparing the bituminous emulsion. The present invention also relates to a cold-poured asphalt mix comprising the bituminous emulsion and aggregate. The present invention also relates to a method for preparing cold-poured asphalt mix from the The present invention also proposes a use for cold-applied asphalt in road applications: mixing the bituminous emulsion with aggregate at temperatures of 60°C or lower.

[0032] Other advantageous characteristics of the additive according to the invention are specified below. -The C12-C22 monoacid comprises a linear or branched, unsaturated hydrocarbon chain. -The dimer comprises a linear or branched, unsaturated hydrocarbon chain. -The additive has a monoacid content of between 25 and 75% by weight relative to the total weight of the additive and a dimer content of between 25 and 75% by weight relative to the total weight of the additive. -The weight ratio between monoacid:dimer is between 3:1 and 1:3, preferably even between 2:1 and 1:2. -The additive has an acid value between 160 and 280 mg KOH / g, preferably between 180 and 260 mg KOH / g. -The additive has a viscosity of less than 1000 mPa.s at 25°C.

[0033] The invention also relates to the use of the additive as defined in one of the above to prepare a bituminous emulsion.

[0034] The invention also relates to a bituminous emulsion comprising bitumen, from 0.1 to 5% by weight, preferably from 0.1 to 3% by weight and preferably from 0.3 to 2% by weight of the additive according to the invention and an aqueous phase, the aqueous phase comprising: a) water, b) at least one cationic surfactant emulsifier, the pH of the aqueous phase being between 1 and 5.5, preferably between 1.5 and 2.5.

[0035] Other advantageous characteristics of the bituminous emulsion according to the invention are specified below. -The emulsion comprises a bitumen content, preferably paraffinic, of between 30 and 70% by weight relative to the total weight of the emulsion. -The emulsion includes adjuvants chosen from thickeners, fluxers, plasticizers.

[0036] The invention relates to the use of the bituminous emulsion according to the invention to prepare a bituminous coating.

[0037] The invention also relates to a cold-poured bituminous coating obtained by mixing aggregates and a bituminous emulsion according to the invention.

[0038] The invention relates to a method for manufacturing a cold-poured bituminous mix comprising a step of mixing the bituminous emulsion as defined above with the aggregates at a temperature between 10°C and 60°C.

[0039] Finally, the invention relates to the use of bituminous asphalt according to the invention in road applications for manufacturing new pavements or wearing courses, for the reinforcement or maintenance of old pavements. Detailed description of the invention

[0040] Other features, aspects, objects and advantages of the present invention will become even clearer upon reading the description that follows.

[0041] Unless otherwise stated, all percentages are mass percentages.

[0042] In this text, the quantities indicated for a given species may apply to that species according to all its definitions (as mentioned in this text), including more restricted definitions.

[0043] It is specified that the expressions "from ... to ..." and "between ... and ...." used in this description should be understood as including each of the mentioned limits. Additive

[0044] The additive for bituminous emulsion according to the invention comprises: -from 20% to 80% by weight relative to the total weight of the additive of at least one C12-C22 monoacid comprising a linear or branched, saturated or unsaturated hydrocarbon chain and -from 20% to 80% by weight relative to the total weight of the additive of at least one C12-C22 monoacid dimer comprising a linear or branched unsaturated hydrocarbon chain, the total weight of monoacid(s) and monoacid dimer(s) representing at least 70% by weight, preferably at least 80% by weight, preferably 90% by weight, relative to the total weight of the additive.

[0045] The composition according to the invention comprises at least one C12-C22 monoacid comprising a linear or branched, saturated or unsaturated hydrocarbon chain. These fatty acids are well known to those skilled in the art. Preferably, the monoacid comprises from 14 to 22 carbon atoms (C14 to C22), and more preferably from 16 to 18 carbon atoms (C16 to C18).

[0046] Preferably, the monoacid is chosen from lauric acid (C12), dodecenoic acid (C12), tridecyl acid (C13), myristic acid (C14), myristoleic acid (C14), pentadecyl acid (C15), palmitic acid (C16), palmitoleic acid (C16), hiragonic acid (C16), sapienic acid (C16), margaric acid (C17), stearic acid (C18), calendic acid (C18), rumenic acid (C18), oleic acid (C18), elaidic acid (C18), vaccenic acid (C18), petroselinic acid (C18), linoleic acid (C18), linolenic acid (C18), γ-linolenic acid (C18), eleostearic acid (C18), parinaric acid (C18), linolelaidic acid (C18), pinolenic acid (C18), nonadecylic acid (C19), arachidic acid (C20), jacaric acid (C20), stearidonic acid (C20), arachidonic acid (C20), gadoleic acid (C20), gondoic acid (C20), icosapentaenoic acid (C20), dihomo-γ-linolenic acid (C20),Arachidonic acid (C20), brassidic acid (C22), erucic acid (C22), ketolic acid (C22), clupanodonic acid (C22), tuberculostearic acid (C19), phytanic acid (C20) taken alone or in mixtures.

[0047] Preferably, the monoacid present in the additive according to the invention is a C12-C22 monoacid comprising a linear or branched, unsaturated hydrocarbon chain.

[0048] Preferably, the monoacid comprising the unsaturated hydrocarbon chain is chosen from dodecenoic acid (C12), myristoleic acid (C14), palmitoleic acid (C16), hiragonic acid (C16), sapienic acid (C16), calendic acid (C18), rumenic acid (C18), oleic acid (C18), elaidic acid (C18), vaccenic acid (C18), petroselinic acid (C18), linoleic acid (C18), linolenic acid (C18), Y-linolenic acid (C18), eleostearic acid (C18), parinaric acid (C18), linolelaidic acid (C18), pinolenic acid (C18), jacaric acid (C20), stearidonic acid (C20), arachidonic acid (C20), gadoleic acid (C20), gondoic acid (C20), icosapentaenoic acid (C20), dihomo-y-linolenic acid (C20), arachidonic acid (C20), brassidic acid (C22), erucic acid (C22), ketolic acid (C22), clupanodonic acid (C22), taken alone or in mixtures.

[0049] The content of monoacid(s) as described above is between 20 and 80% by weight relative to the total weight of the additive, advantageously between 25 and 75% by weight, more advantageously between 35 and 65% by weight, and even more advantageously between 45 and 55% by weight.

[0050] The monoacid of the additive according to the invention is preferably chosen from: -the product with CAS number 61790-12-3 derived from pine oil (called Tall Oil Fatty Acid or TOFA). This product contains mono-fatty acids such as oleic acid (C18) and linolenic acid (C18) and linoleic acid (C18), - the product with CAS number 67701-08-0 derived from soybean oil. This product includes oleic acid (C18), linoleic acid (C18), linolenic acid (C18), palmitic acid (C16) and stearic acid (C18), - the product with CAS number 120962-03 derived from canola oil, - the product with CAS number 8002-13-09 derived from rapeseed oil, - the product with CAS number 8001-30-7 derived from corn oil, - the product with CAS number 8002-03-7 derived from peanut oil.

[0051] The additive according to the invention also comprises at least one C12-C22 monoacid dimer comprising an unsaturated, linear or branched hydrocarbon chain.

[0052] Preferably, the unsaturated fatty acids used to obtain dimerized fatty acids are generally and most often unsaturated fatty acids of 12 to 22 carbon atoms (C12 to C22), preferably of 14 to 22 carbon atoms (C14 to C22), preferably of 16 to 18 carbon atoms (C16 to C18).

[0053] Preferably, a mono-fatty acid dimer is a dimer formed from two mono-acids possessing a monounsaturated or polyunsaturated hydrocarbon chain. Therefore, this dimer is a C24-C44 diacid.

[0054] It is possible to polymerize a fatty acid or a mixture containing several different fatty acids. This reaction, which polymerizes the fatty acid chains, is generally a Diels-Alder reaction leading to a C6 ring (for more information see Kirk Othmer Encyclopedia of Chemical Technology, Vol. 7, p. 768 or "The dimer acids", Humko Sheffield, 1975).

[0055] Preferably, the additive comprises a mixture of dimerized fatty acids (linear C18 monounsaturated dimers) of CAS number 61788-89-4.

[0056] The content of monoacid(s) dimer(s) is between 20 and 80% by weight relative to the total weight of the additive, preferably 25 and 75% by weight, more advantageously between 35 and 65% by weight and even more advantageously between 45 and 55% by weight.

[0057] Preferably, the additive comprises a monoacid content of between 25 and 75% by weight relative to the total weight of the additive and a monoacid dimer content of between 25 and 75% by weight relative to the total weight of the additive.

[0058] The additive according to the invention comprises at least 70% by weight relative to the total weight of the additive, preferably at least 80%, and even more preferably at least 90% by weight of one or more monoacids and one or more dimers as defined above.

[0059] Preferably, the additive consists of a monoacid content of between 25 and 75% by weight relative to the total weight of the additive and a dimer content of between 25 and 75% by weight relative to the total weight of the additive.

[0060] Preferably, the weight ratio between monoacid:dimer is between 3:1 and 1:3, preferably even between 2:1 and 1:2.

[0061] Preferably, the additive does not contain polymerized acid(s), for example, acid trimers, with the exception of the dimers described above. The sum of the weight contents of monoacid(s) and diacid(s) represents 100% by weight of the total weight of the additive, within the limits of measurement errors and excluding impurities.

[0062] Preferably, the additive has a viscosity of less than 1000 mPa.s at 25°C measured using an Anton Paar MCR301 rheometer with a 25 mm diameter plane-plane device, a 1 mm gap and a shear rate of 100 s -1 the viscosity of the additive is advantageously less than 900 mPa.s, more advantageously less than 600 mPa.s and even more advantageously less than 400 mPa.s.

[0063] Preferably, the additive has an acid value between 160 and 280 mg KOH / g, preferably between 180 and 260 mg KOH / g, measured according to ISO 660 (2020).

[0064] The invention also relates to the use of the additive as defined above to prepare a bituminous emulsion. Bituminous emulsion

[0065] The invention also relates to a bituminous emulsion comprising bitumen, 0.1 to 5% by weight of the additive as defined above, and an aqueous phase, the aqueous phase comprising: - water, - at least one emulsifier, typically a cationic surfactant type emulsifier, preferably comprising at least one amido-amine and / or polyamine function, and the pH of the aqueous phase being between 1 and 5.5, preferably between 1.5 and 2.5.

[0066] The bitumens used in the emulsion according to the present invention are bitumens from various sources. These include, firstly, bitumens of natural origin, those contained in deposits of natural bitumen, natural asphalt, or oil sands.

[0067] The bitumens according to the invention are also bitumens derived from crude oil refining. The bitumens are obtained from atmospheric and / or vacuum distillation of petroleum. These bitumens may also be optionally oxidized, blown, viscous-reduced, and / or deasphalted. The bitumens may be hard-grade or soft-grade. The different bitumens obtained by refining processes can be combined to obtain the best technical compromise.

[0068] The bitumens used can also be fluxed bitumens by the addition of volatile solvents, petroleum-based fluxants, carbochemical fluxants and / or plant-based fluxants.

[0069] Polymer-modified bitumens can also be used. Examples of polymers include, but are not limited to, thermoplastic elastomers such as linear or star-shaped styrene-butadiene copolymers (SBR, SBS) or styrene-isoprene copolymers (SIS), possibly crosslinked; ethylene-vinyl acetate copolymers; ethylene (or propylene, or butylene) olefinic homopolymers and copolymers; polyisobutylenes; polybutadienes; polyisoprenes; polyvinyl chloride; rubber powders; and any other polymer used for modifying bitumens and their mixtures. Generally, 2 to 10% polymer by weight relative to the bitumen weight is used.

[0070] Synthetic bitumens, also called clear, pigmentable, or colorable bitumens, can also be used. These bitumens contain little or no asphaltenes and can therefore be colored. These synthetic bitumens are based on petroleum resin and / or indene-coumarone resin and lubricating oil, as described, for example, in patent EP 179510.

[0071] Advantageously, the bitumen is a bitumen with a penetration capability measured according to the NF EN 1426 standard of June 2007 ranging from 10 to 300, preferably from 20 to 220, more preferably from 70 to 220.

[0072] Preferably, the bitumen according to the invention is chosen from unmodified crude oil refining bitumens.

[0073] Preferably, the bitumen used according to the invention is fresh bitumen. For the purposes of this invention, "fresh" bitumen means bitumen that has not yet been mixed with aggregates or spread. In English, fresh bitumen is called "neat bitumen".

[0074] The bitumen used according to the invention may also be a recycled bituminous product. In this case, the mineral aggregates used in asphalt mixes are generally quarry products and are increasingly used in combination with aggregates recycled from previously manufactured asphalt mixes. Such recycled aggregates are known generically as reclaimed asphalt pavement (RAP), for example, as defined in the French standard AFNOR XP P98-135 of December 2001 or in the Asphalt Handbook, MS-4, 7 e edition, published by the Asphalt Institute, United States.

[0075] RAP also includes recycled asphalt mixes where mineral aggregates are replaced in part or in full by other common components, such as, by limiting examples, organic and inorganic fibers (e.g. glass, metal or carbon fibers, cellulose, cotton, etc.), polymers (e.g. polypropylenes, polyesters, poly(vinyl alcohols), polyamides, polyurethanes, polyureas, ethylene-vinyl acetate (EVA) and styrene-butadiene-styrene (SBS) copolymers).

[0076] Reclaimed or recycled aggregates, commonly called reclaimed asphalt pavement (RAP), are of particular interest. These aggregates result from the milling, or other grinding methods, of previous asphalt mixes, which are generally damaged and require replacement. These recycled aggregates contain bitumen used as a binder during the initial production.

[0077] Other sources of bituminous products that can also be recycled in the manufacture of asphalt mixes include, for example, roofing products (e.g., shingles or waterproofing membranes, as well as waste from their production), and thermal insulation or soundproofing materials. These bituminous products generally do not contain mineral fillers.

[0078] Preferably, the bituminous emulsion includes paraffinic bitumen.

[0079] Preferably, the emulsion according to the invention comprises 30 to 70% by weight of bitumen relative to the total weight of the emulsion.

[0080] The emulsion according to the invention comprises at least one emulsifier contributing to the stability of the emulsion.

[0081] Non-limiting examples of emulsifiers for obtaining such emulsions include alkylpolyamines, alkylamidopolyamines, alkylamidoimidazolines, quaternary alkylmonoamines, quaternary alkylpolyamines, amino derivatives of lignin obtained by direct amination or by the Mannich reaction or by the reaction between Kraft lignin and glycidylamine, and mixtures thereof. In one advantageous embodiment, the emulsifier is an alkylamidopolyamine.

[0082] Preferably, the bituminous emulsion comprises 0.1 to 3% by weight of emulsifier relative to the total weight of the bituminous emulsion, preferably 0.3 to 2% by weight and preferably 0.5 to 1.5% by weight.

[0083] Preferably, the bituminous emulsion comprises 0.1 to 5% by weight of the additive relative to the total weight of the emulsion of the additive as defined above, preferably 0.1 to 3% by weight and preferably 0.3 to 2% by weight.

[0084] Preferably, the bituminous emulsion composition may include a sufficient quantity of a mineral or organic acid other than the aforementioned monoacids and diacids, preferably a mineral acid.

[0085] The acid content is adjusted to achieve a pH of the aqueous phase of the bituminous emulsion between 1 and 5.5, preferably between 1.5 and 2.5.

[0086] In a preferred embodiment, the acid is advantageously hydrochloric acid.

[0087] The bituminous emulsion may optionally include one or more adjuvants commonly used in the field, including, but not limited to, natural or synthetic latexes, thickeners, fluxers, plasticizers, and any other additives that allow adjustment of the properties of the emulsion, such as the process additives mentioned in patent EP1057873 B1.

[0088] The invention also relates to a method for preparing the bituminous emulsion comprising a step of mixing the bitumen with an aqueous phase as defined above, according to any methods well known to those skilled in the art, for example by means of a colloidal mill. The invention also relates to a process for preparing the bituminous emulsion comprising a step of mixing the bitumen, the additive according to the invention and an aqueous phase comprising at least one emulsifier, typically a cationic surfactant type emulsifier, preferably comprising at least one amido-amine and / or polyamine function, the pH of the aqueous phase being between 1 and 5.5, preferably between 1.5 and 2.5, according to any methods well known to those skilled in the art.

[0089] The invention also relates to the use of the bituminous emulsion as defined above to prepare a bituminous coating. Cold-poured asphalt

[0090] The invention also relates to a cold-poured bituminous mix obtained by mixing aggregates and a bituminous emulsion as defined above.

[0091] The asphalt mix advantageously comprises 1 to 40% by weight relative to the total weight of the asphalt mix, preferably 3 to 30% by weight, more preferably 6 to 20% by weight and even more preferably 8 to 15% by weight of the bituminous emulsion defined above.

[0092] The invention also relates to a process for manufacturing cold-poured bituminous mix comprising a step of mixing the bituminous emulsion with the aggregates at a temperature between ambient temperature, i.e. from 10 to 40°C depending on the location and the seasons, and 60°C, according to all methods well known to those skilled in the art.

[0093] The aggregates that can be used for the preparation of asphalt mixes according to the present invention can be of any type known to those skilled in the art. Among the aggregates usable for the asphalt mixes of the present invention, one can mention in particular, without limitation, aggregates of mineralogical nature, for example of igneous nature, such as granites, porphyries, basalts, of metamorphic nature, such as schists, gneisses, and of sedimentary nature of siliceous type, such as flints, quartzites, and of carbonate type, such as limestones, dolomites, but also asphalt (or recycled) aggregates, slags, crushed concrete, and others, as well as mixtures of such aggregates.

[0094] The emulsions of the present invention are thus particularly suitable for the preparation of asphalt mixes, for example semi-warm asphalt mixes, i.e., where the temperature of the aggregates during the mixing phase with the bitumen emulsion is between ambient temperature, which can range from 0°C to 40°C, and 60°C, for example also cold asphalt mixes, among which we can mention, in a non-limiting way, gravel emulsions (structural or reprofiling), cold bituminous concrete, dense, semi-dense or open stockpiled asphalt mixes, and others. Wearing course

[0095] The invention also relates to a method for manufacturing a wearing course comprising the following successive steps: 1) Mixing the bituminous emulsion with the aggregates at a temperature between ambient temperature (typically 10 to 40°C) and 60°C, 2) spreading of the bituminous coating at a temperature between ambient temperature (typically 10 to 40°C) and 40°C.

[0096] The invention also relates to the use of bituminous mix in road applications for manufacturing new pavements or wearing courses, for the reinforcement or maintenance of old pavements. Examples Example 1: Evaluation of additive viscosity Preparation of additives

[0097] The following additives were prepared according to Table 1 below. Contents are expressed as a percentage by weight: [Table 1] 1 The product with CAS number 61788-89-4 is a mixture of G mono-fatty acid dimers; 2The product with CAS number 61790-12-3 is a mixture comprising linear and unsaturated mono-C fatty acids derived from pine oil (also known as Tall Oil Fatty Acid or TOFA); 3 The product with CAS number 67701-08-0 is a mixture of C16-C18 unsaturated mono-fatty acids derived from soybean oil. Evaluation of additives

[0098] The viscosity of the compositions is measured using an Anton Paar MCR501 rheometer equipped with a 25 mm plane-plane geometry. The measurement is performed under rotation at a shear rate of 100 s⁻¹ -1 , with a gap of 1 mm, and at a temperature of 25°C.

[0099] The viscosity of the additives is shown in Table 2 below. The values ​​are expressed in mPa·s: [Table 2]

[0100] Adding mono-fatty acids to the mixture in a certain quantity allows for a significant reduction in the viscosity of the mixture.

[0101] The specific viscosity of the additives according to the invention 3 to 5 thus has the advantage of being much easier to use. Example 2: Evaluation of the breaking time of the emulsion of additive-enhanced bituminous mixes and the breaking time after internal cohesion buildup of additive-enhanced bituminous mixes Preparation of bituminous emulsions

[0102] The following bituminous asphalt emulsions were prepared according to the table 3 below. The contents are expressed as a percentage by weight: [Table 3]

[0103] The bitumen is 70 / 100 paraffinic bitumen marketed by the company Total and coming from the Gonfreville plant.

[0104] The amido-amine type emulsifier is marketed under the trade name Polyram®L950 by the company Arkema France.

[0105] Additives 1, 2 and 4 are those described in example 1.

[0106] The amount of hydrochloric acid is 0.9% by weight so that the pH of the bituminous emulsion is equal to 2. Preparation of bituminous mixtures

[0107] The following bituminous mixes were prepared according to Table 4 below. The contents are expressed as a percentage by weight: [Table 4]

[0108] The aggregate is 0 / 8 aggregate from the Ambazac quarry.

[0109] The cement is a CEM II 32.5 type cement. The term "cement" means any hydraulic binder composed of finely ground inorganic matter 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 standards (2000-06-01)).

[0110] Bituminous emulsions 6 to 9 correspond to the emulsions listed in Table 3. Evaluation of bituminous mixtures

[0111] The previously prepared bituminous mixtures were tested to evaluate the breaking time as well as the time to build cohesion (Hilt Cohesion Test). Break time assessment

[0112] During the mixing of asphalt mixes, the breaking time, or workability time, is visually assessed. This time corresponds to the time it takes for the emulsion to destabilize during mixing, that is, the time at which a change of state occurs. This test is carried out at a controlled temperature between 20°C and 25°C. Evaluation of internal cohesion based on maturation time

[0113] Internal cohesion as a function of ripening time is assessed using a Hilt Cohesion Test

[0114] The Hilt Cohesion Test (HCT) is a non-standardized test described in the CEREMA guide (ISBN: 978-2-37180-202-5) on cold-cast materials in 2017.

[0115] A bituminous asphalt slab (120 x 120 x 14 mm) listed in Table 5 is placed on a support with a removable section. After one hour of curing, one-third of the slab is placed on the previously removed section. One-third of the slab is then suspended in mid-air. The HCT test then consists of measuring the slab's breaking time.

[0116] The values ​​obtained are expressed in the table below: [Table 5]

[0117] The emulsion breaking time remains satisfactory, despite the addition of the additive according to the invention.

[0118] The bituminous mix according to the invention (Asphalt Mix 14), incorporating the additive as described above, exhibits a longer breaking time during the HCT test than the comparative bituminous mixes prepared: without fatty acids (Asphalt Mixes 11), or comprising only dimerized fatty acids (Asphalt Mixes 12: additive not meeting the viscosity criterion), or comprising only fatty acid monomers (Asphalt Mixes 13). The bituminous mix according to the invention has the advantage of accelerating cohesion development, allowing for a faster resumption of traffic when the material is used, and includes a pumpable additive thanks to its reduced viscosity.

[0119] These examples show that the mixture of monoacids and dimers allows for a rapid rise in cohesion, without significantly altering the breaking time. Example 3: Time required for internal cohesion growth of bituminous mixtures at 20°C using paraffinic bitumens and aggregates from different sources Preparation of bituminous emulsions

[0120] The following bituminous emulsions were prepared according to Table 6 below. The contents are expressed as a percentage by weight: [Table 6] - Bitumen 1 is 70 / 100 paraffinic bitumen marketed by Total and sourced from the Gonfreville plant. - Bitumen 2 is 70 / 100 paraffinic bitumen marketed by Total and sourced from the Antwerp plant.

[0121] The amount of hydrochloric acid is 0.9% by weight so that the pH of the bituminous emulsion is equal to 2.

[0122] The amido-amine type emulsifier is marketed under the trade name Polyram®L950 by the company Arkema France.

[0123] Additives 1, 4 and 5 are defined in example 1. Preparation of bituminous mixtures

[0124] The following bituminous mixtures were prepared according to Table 7 below. The contents are expressed as a percentage by weight: [Table 7]

[0125] Aggregate 1 is 0 / 8 aggregate from the Ambazac quarry. The cement is a CEM II 32.5 type cement. The term "cement" means any hydraulic binder composed of finely ground inorganic matter 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 standards (2000-06-01)). Asphalt paving evaluation

[0126] The previously prepared bituminous mixes were tested to evaluate their breaking time using the Hilt Cohesion Test. The values ​​obtained are shown in Table 8 below: [Table 8]

[0127] The bituminous mixes according to the invention (Asphalt Mixes 20 and 22) exhibit a longer failure time during the HCT test than the comparative bituminous mixes prepared without fatty acids (Asphalt Mixes 19 and 21). The bituminous mixes according to the invention have the advantage of accelerating cohesion development, allowing for a faster resumption of traffic when the material is used, and include a pumpable additive thanks to its reduced viscosity.

Claims

Demands 1. Additive for bituminous emulsion comprising: -from 20% to 80% by weight relative to the total weight of the additive of at least one C12-C22 monoacid comprising a linear or branched, saturated or unsaturated hydrocarbon chain and -from 20% to 80% by weight relative to the total weight of the additive of at least one C12-C22 monoacid dimer comprising a linear or branched unsaturated hydrocarbon chain, the total weight of monoacid(s) and monoacid dimer(s) representing at least 70% by weight, preferably at least 80% by weight, preferably 90% by weight, relative to the total weight of the additive.

2. Additive according to claim 1, characterized in that the C12-C22 monoacid comprises an unsaturated, linear or branched hydrocarbon chain.

3. Additive according to any one of the preceding claims, characterized in that it comprises a monoacid content of between 25 and 75% by weight relative to the total weight of the additive and a dimer content of between 25 and 75% by weight relative to the total weight of the additive.

4. Additive according to any one of the preceding claims, characterized in that the weight ratio between monoacid:dimer is between 3:1 and 1:3, preferably also between 2:1 and 1:

2.

5. Additive according to any one of the preceding claims, characterized in that it has an acid value of between 160 and 280 mg KOH / g, preferably between 180 and 260 mg KOH / g.

6. Additive according to any one of the preceding claims, characterized in that it has a viscosity of less than 1000 mPa.s at 25°C.

7. Use of the additive as defined in any one of claims 1 to 6 to prepare a bituminous emulsion.

8. Bituminous emulsion comprising bitumen, from 0.1 to 5% by weight, preferably from 0.1 to 3% by weight and preferably from 0.3 to 2% by weight of the additive as defined in any one of claims 1 to 7 and an aqueous phase, the aqueous phase comprising: a) water, b) at least one cationic surfactant emulsifier, the pH of the aqueous phase being between 1 and 5.5, preferably between 1.5 and 2.

5.

9. Emulsion according to claim 8, characterized in that it comprises a bitumen content, preferably paraffinic, of between 30 and 70% by weight relative to the total weight of the emulsion.

10. Emulsion according to claim 8 or 9, characterized in that it comprises adjuvants selected from thickeners, fluxers, plasticizers.

11. Use of the bituminous emulsion as defined in any one of claims 8 to 10 to prepare a bituminous mix.

12. Cold-poured bituminous mix comprising aggregates and a bituminous emulsion as defined in any one of claims 8 to 10.

13. Method for manufacturing a cold-poured bituminous mix comprising a step of mixing the bituminous emulsion as defined in claims 8 to 10 with the aggregates at a temperature between 10°C and 60°C.

14. Use of bituminous mix as defined in claim 12 in road applications for manufacturing new pavements or wearing courses, for the reinforcement or maintenance of old pavements.

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