Bituminous composition comprising biochar, preparation method thereof and uses of same

Abstract

The invention relates to a bituminous composition comprising: - at least one bitumen base; - at least one elastomer, preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene; - biochar.

Description

[0001] Bituminous composition comprising biochar, preparation process and uses

[0002] The present invention relates to a bituminous composition comprising bitumen, an elastomer and biochar, optionally crosslinked. The invention also relates to a process for preparing a bituminous composition according to the invention. The invention finally relates to the use of a bituminous composition according to the invention, in particular for road and / or industrial applications.

[0003] Bitumen is the main hydrocarbon component used in road construction and civil engineering. It is used, for example, in road surfacing or as a waterproofing membrane. Bitumen is generally obtained from residues from the atmospheric and / or vacuum distillation of crude oil.

[0004] Oil resources are, however, limited. Indeed, "proven reserves" of oil reached more than 200 billion tonnes of oil equivalent (TOE) worldwide in 2018, according to experts at British Petroleum (who have been taking stock of the resource since 1980). Although significant, these reserves could only cover 50.2 years of annual consumption at the rate of 2017. These figures are confirmed by the French Alternative Energies and Atomic Energy Commission (CEA) and the International Energy Agency (IEA). It is therefore necessary to limit our oil consumption as much as possible.

[0005] Furthermore, oil exploitation is responsible for the release of significant quantities of greenhouse gases into the atmosphere, which have a significant impact on global warming. It is therefore necessary to limit our consumption of oil, particularly bitumen, in order to minimize the overall rise in Earth's temperatures.

[0006] In order to maintain and / or improve the characteristics, in particular the mechanical properties, of a conventional bitumen, it is also known to use crosslinked bitumen / polymer compositions in which the bitumen (formed from one or more types of bitumen) is mixed with one or more functional polymers, in particular styrene and butadiene elastomers, these elastomers being chemically crosslinked in situ, possibly using a coupling or crosslinking agent, for example sulfur or at least one of its precursors. Optimized mechanical characteristics are indeed crucial for road surfacing applications. The carbon footprint associated with these bitumen / polymer compositions is, however, much higher than that of pure bitumen. Indeed, the carbon footprint of pure bitumen is estimated at 0.2 kg of CO2 equivalent per kg of bitumen (estimate made by the Eurobitume association).The carbon footprint of a polymer, particularly a styrene butadiene elastomer, is currently estimated at between 2.2 and 3.3 kg of CO2 equivalent per kg of polymer, depending on the process used and plant optimization. There is therefore still a need for bituminous compositions, particularly bitumen / polymer compositions, with a significantly reduced carbon footprint.

[0007] WO 2022 / 032152 describes the preparation of bituminous compositions incorporating biochar. However, this document does not describe bituminous compositions modified by the integration of a polymer. In particular, it does not deal with bitumen / polymer compositions, possibly crosslinked.

[0008] There therefore remains a need for bituminous compositions whose content of material(s) of fossil origin, in particular derived from petroleum, is significantly reduced compared to the compositions of the prior art.

[0009] In particular, there remains a need for bituminous compositions having mechanical properties, in particular elastic properties, which are improved compared to the polymer-free compositions of the prior art, and whose content of material(s) of fossil origin, in particular derived from petroleum, is reduced compared to the compositions of the prior art.

[0010] Even more particularly, there remains a need for bitumen / polymer compositions (possibly crosslinked) whose content of material(s) of fossil origin, in particular derived from petroleum, is reduced compared to the compositions of the prior art.

[0011] There also remains a need to provide bituminous compositions with a reduced carbon footprint, compared to prior art compositions.

[0012] In particular, there remains a need for bituminous compositions having mechanical properties, in particular elastic properties, which are improved compared to the polymer-free compositions of the prior art, and whose carbon footprint is significantly reduced compared to the compositions of the prior art.

[0013] Even more particularly, there remains a need for bitumen / polymer compositions (possibly crosslinked) whose carbon footprint is reduced, compared to the compositions of the prior art.

[0014] The inventors have discovered that it is possible to reduce the content of material(s) of fossil origin in a bituminous composition, in particular in a bitumen / polymer composition, by integrating biochar. The inventors have also discovered that it is possible to reduce the carbon footprint of prior art bituminous compositions, in particular bitumen / polymer compositions, by integrating biochar. In particular, the inventors have discovered that it is possible to integrate biochar into a bituminous composition, in particular in a bitumen / polymer composition, without significantly affecting the properties of the final material. The final material has properties that are substantially equivalent, or even improved, compared to those of prior art biochar-free bituminous compositions, in particular compared to prior art biochar-free bitumen / polymer compositions.

[0015] Summary of the invention

[0016] The invention relates to a bituminous composition comprising:

[0017] - at least one bitumen base,

[0018] - at least one elastomer, preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene,

[0019] - biochar.

[0020] Preferably, the biochar is derived from the thermochemical conversion of biomass selected from forest products; crop residues; animal waste; municipal waste and any of their mixtures.

[0021] Preferably, the biochar is derived from the thermochemical conversion of biomass selected from hardwoods, in particular ash wood; grain husks; nut shells, in particular cashew nuts; food waste; coffee grounds and any mixture thereof.

[0022] According to one embodiment, the bituminous composition as defined above and described in detail below has a reduced carbon footprint, compared to the same composition free of biochar.

[0023] The invention also relates to a crosslinked bitumen / polymer composition, obtained by crosslinking, in particular chemical or thermal, of a bituminous composition as defined above and described in detail below.

[0024] According to one embodiment, the crosslinked bitumen / polymer composition as defined above and described in detail below has a reduced carbon footprint, compared to the same composition free of biochar.

[0025] The invention also relates to a process for preparing a bituminous composition as defined above and described in detail below, in particular a crosslinked bitumen / polymer composition as defined above and described in detail below, this process comprising:

[0026] 1) bringing the following components into contact:

[0027] - at least one bitumen base,

[0028] - at least one elastomer, and

[0029] - biochar, 2) the mixture of components.

[0030] Preferably, the mixing of the components is carried out under heating and stirring, preferably at a temperature ranging from 90°C to 230°C, more preferably from 120°C to 200°C, even more preferably from 150°C to 180°C.

[0031] The invention also relates to the use of a bituminous composition as defined above and described in detail below, in particular a crosslinked bitumen / polymer composition as defined above and described in detail below, for preparing a surface coating, a hot mix, a cold mix, a cold-poured mix, an emulsion gravel or a wearing course, said binder being associated with aggregates and / or recycled millings.

[0032] The invention also relates to a bituminous coating comprising a bituminous composition as defined above and described in detail below, in particular a crosslinked bitumen / polymer composition as defined above and described in detail below, mixed with aggregates and / or recycled millings, and optionally mineral and / or synthetic fillers.

[0033] The invention also relates to an asphalt comprising a bituminous composition as defined above and described in detail below, in particular a crosslinked bitumen / polymer composition as defined above and described in detail below, in a mixture with mineral and / or synthetic fillers.

[0034] The invention also relates to the use of a bituminous composition as defined above and described in detail below, in particular a crosslinked bitumen / polymer composition as defined above and described in detail below, for preparing a waterproofing coating, a membrane or an impregnation layer.

[0035] The invention finally relates to the use in a bituminous composition as defined above and described in detail below, in particular of a crosslinked bitumen / polymer composition as defined above and described in detail below, of biochar to reduce the carbon footprint of said bituminous composition (optionally crosslinked).

[0036] Detailed description of the invention

[0037] In the remainder of the description, and unless explicitly indicated otherwise, the quantities of the various components present in a bituminous composition according to the invention are given in % by mass, relative to the total mass of the composition (hereinafter referred to as % m / m).

[0038] Likewise, and unless explicitly stated otherwise, the standards mentioned in the remainder of the description correspond to the standard in force on the date of 1 erDecember 2022. The invention firstly relates to a bituminous composition comprising:

[0039] - at least one bitumen base,

[0040] - at least one elastomer, and

[0041] - biochar.

[0042] Preferably, the bituminous composition according to the invention comprises:

[0043] - at least one bitumen base,

[0044] - at least one elastomer comprising at least one styrene-butadiene-styrene unit, and

[0045] - biochar.

[0046] Bitumen base

[0047] The bitumen(s) used to prepare a bitumen / polymer composition according to the invention are called “bitumen base”.

[0048] Among the bitumens that can be used according to the invention, mention may firstly be made of bitumens of natural origin, those contained in deposits of natural bitumen, natural asphalt or oil sands and bitumens originating from the refining of crude oil. In the context of the invention, the bitumen(s) used are advantageously chosen from bitumens originating from the refining of crude oil, in particular bitumens containing asphaltenes or pitches. The bitumens can be obtained by conventional processes for the manufacture of bitumens in refineries, in particular by direct distillation and / or vacuum distillation of oil. These bitumens can optionally be visbroken and / or deasphalted and / or rectified in air. It is common practice to carry out vacuum distillation of atmospheric residues originating from the atmospheric distillation of crude oil.This manufacturing process therefore corresponds to the succession of atmospheric distillation and vacuum distillation, the feedstock feeding the vacuum distillation corresponding to the atmospheric residues. These vacuum residues from the vacuum distillation tower can also be used as bitumens. It is also common to inject air into a feedstock usually composed of distillates and heavy products from the vacuum distillation of atmospheric residues from the distillation of oil. This process makes it possible to obtain a blown, or semi-blown, or oxidized, or air-rectified, or partially air-rectified bitumen.

[0049] Different bitumens obtained by refining processes can be combined in the compositions according to the invention, to obtain the best compromise, in terms of technical performances. In conventional processes for mixing different bitumens, the operation is carried out at temperatures between 100°C and 200°C, preferably between 140°C and 200°C, and with stirring for a period of at least 10 minutes, preferably between 30 minutes and 10 hours, more preferably between 1 hour and 6 hours. The temperature and duration of heating vary according to the quantity of bitumen used and are defined by standard NF EN 12594. Blown bitumens can be manufactured in a blowing unit, by passing a flow of air and / or oxygen through a starting bitumen or bitumen mixture. This operation can be carried out in the presence of an oxidation catalyst, for example phosphoric acid.

[0050] Generally, blowing is carried out at high temperatures, in the order of 200 to 300°C, for relatively long periods of time, typically between 30 minutes and 2 hours, continuously or in batches. The blowing time and temperature are adjusted according to the desired properties of the blown bitumen and the quality of the starting bitumen.

[0051] Among the bitumens that can be used according to the invention, recycling bitumens can also be mentioned.

[0052] Bitumens can be hard grade bitumens (such as grades 10 / 20 and 20 / 30) or soft grade bitumens (such as grade 160 / 220) as defined by EN 12591.

[0053] The invention is particularly suitable for cases where the bitumen base consists of a hard grade bitumen or a mixture of hard grade bitumens, in particular chosen from bitumens of grade 35 / 50, 20 / 30 and 10 / 20.

[0054] The bitumen bases that can be used in the context of the invention preferably have a penetrability, measured at 25°C according to standard EN 1426, of 5 to 330 1 / 10 mm, preferably between 10 and 220 1 / 10 mm, more preferably from 10 to 120 1 / 10 mm. In a well-known manner, the so-called “needle penetrability” measurement is carried out by means of a standardized test NF EN 1426 at 25°C (P25). This penetrability characteristic is expressed in tenths of a millimeter (dmm or 1 / 10 mm). The needle penetrability, measured at 25°C, according to the standardized test NF EN 1426, represents the measurement of the penetration into a sample of bitumen, after a time of 5 seconds, of a needle whose weight with its support is 100 g.

[0055] Preferably, the bitumen / polymer composition according to the invention comprises at least 40% by mass of bitumen, relative to the total mass of the bitumen / polymer composition, preferably at least 50% by mass, more preferably at least 60% by mass, advantageously at least 70% by mass, more advantageously at least 80% by mass, even more advantageously at least 85% by mass.

[0056] Advantageously, the bitumen / polymer composition according to the invention comprises from 40% to 99.9% by mass, relative to the total bitumen / polymer composition, preferably from 50% to 99% by mass, more preferably from 60% to 95% by mass, even more preferably from 70% to 95% by mass, advantageously from 75% to 95% by mass, more advantageously from 80% to 95% by mass Copolymer

[0057] The elastomer is not particularly limited provided that it exhibits the qualities required for coating compositions. Such elastomers are well known in the art and are generally rubbery polymers. In a preferred embodiment, the elastomer comprises styrene butadiene styrene (SBS), hydrogenated SBS, styrene isoprene styrene (SIS), styrene ethylene butadiene styrene (SEBS) and / or polyisobutadiene (PIB).

[0058] Preferably, the elastomer is typically selected from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene.

[0059] According to a preferred embodiment, the elastomer comprises at least one styrene butadiene styrene unit. In particular, the elastomer is preferably chosen from copolymers comprising at least one styrene butadiene styrene unit.

[0060] Advantageously, the elastomer is chosen from styrene butadiene styrene copolymers and mixtures of styrene butadiene styrene and styrene butadiene copolymers.

[0061] Preferably, the elastomer is chosen from block copolymers of formula S-BS, in which:

[0062] - each S, which may be identical or different, independently represents a block based on monovinyl aromatic hydrocarbon monomers,

[0063] - B represents a block based on butadiene monomers, said block B comprising pendant vinyl groups.

[0064] For the purposes of the invention, the term "block" means a polymer chain obtained by the polymerization of one or more monomers of the same chemical nature. A block is advantageously made up of the repetition of the same monomer.

[0065] Preferably, the elastomer is free of ethylene-derived units.

[0066] In said block copolymers of formula SBS, the S blocks together represent at least 15 mol% of the total number of moles of monomeric units of the block copolymer. Said block copolymers have a weight-average molecular mass ranging from 40,000 to 500,000 g / mol and have a content of pendant vinyl groups contained in the B block, which is greater than or equal to 20 mol%, relative to the total number of moles of monomeric units of the block copolymer. These copolymers may be called, more simply, hereinafter, SBS elastomer. In general, the two S blocks of the heat-crosslinkable SBS elastomer are identical.

[0067] In the context of the invention, butadiene means 1,3-butadiene which is a conjugated diene. When butadiene, or more generally a conjugated diene, is polymerized via a 1,2-addition mechanism, the result is a vinyl group (also called a vinyl group) pendant relative to the backbone of the polymer. The pendant vinyl groups of the SBS block copolymer therefore correspond to the 1,2-addition polymerization of the conjugated diene monomers, and in particular of the majority butadiene monomers, within the B block. The units obtained by the polymerization of butadiene according to a 1,2-addition mechanism or according to a 1,4-addition mechanism have the same molar mass.

[0068] In particular, the monovinyl aromatic hydrocarbon monomer(s) present in the S blocks of the SBS heat-crosslinkable elastomer are chosen from styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, alpha-methylstyrene, vinylnaphthalene, vinyltoluene and vinylxylene or mixtures thereof. The preferred monovinyl aromatic hydrocarbon monomer according to the present invention is styrene, which is used, for the constitution of the S blocks as the sole monomer, or as the major monomer in mixtures with minor proportions of one or more other monomers such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, alpha methylstyrene, vinylnaphthalene, vinyltoluene and vinylxylene, namely, in proportions of at most 10% by mass, relative to the totality of the monovinyl aromatic hydrocarbon monomers present in said S blocks.The use of styrene as the sole monomer is particularly preferred in the present invention for the constitution of the S blocks of the SBS elastomer. Thus, the monovinylaromatic hydrocarbon monomers from which the S blocks of the SBS copolymers with thermally crosslinkable blocks are derived may be, independently, any monovinylaromatic hydrocarbon monomer as previously described and are preferably styrene.

[0069] The block B based on butadiene monomers entering into the composition of the mentioned block copolymers SBS is, preferably, solely composed of butadiene monomers, or of a mixture of butadiene comprising minor proportions of one or more other structurally related conjugated dienes, and in particular chosen from isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene, in particular representing at most 10% by mass, relative to the totality of the conjugated dienes present in the block B. Preferably, the monomers constituting the block B are exclusively butadiene monomers.

[0070] The SBS heat-crosslinkable block elastomer used in the context of the invention has a weight-average molecular mass Mw, ranging from 40,000 to 500,000 g / mol. Preferably, the SBS heat-crosslinkable block elastomer has a weight-average molecular mass Mw, less than or equal to 400,000 g / mol, more preferably less than or equal to 250,000 g / mol, even more preferably less than or equal to 200,000 g / mol and advantageously less than or equal to 150,000 g / mol.

[0071] Preferably, the SBS block copolymer used in the context of the invention has a weight-average molecular mass Mw greater than or equal to 50,000 g / mol, more preferably greater than or equal to 65,000 g / mol, even more preferably greater than or equal to 75,000 g / mol, and advantageously greater than or equal to 100,000 g / mol. According to particular embodiments, the SBS block copolymer has a weight-average molecular mass Mw in any range corresponding to the maximum and minimum values ​​mentioned above, and advantageously in the range from 100,000 to 150,000 g / mol.

[0072] As indicated above, the SBS block copolymer used in the context of the invention has a content of pendant vinyl groups greater than or equal to 5% by mole, relative to the total number of moles of monomeric units of the copolymer. This vinyl content, determined by coupling 13C NMR (carbon nuclear magnetic resonance) and 1H NMR (proton nuclear magnetic resonance) spectroscopy techniques, makes it possible to characterize the polymer.

[0073] Preferably, the SBS block copolymer preferably has a content of pendant vinyl groups greater than or equal to 5 mol%, relative to the total number of moles of monomeric units of the SBS copolymer, preferably greater than or equal to 10%.

[0074] According to one embodiment, the SBS block copolymer preferably has a content of pendant vinyl groups less than or equal to 50 mol%, relative to the total number of moles of monomeric units of the SBS copolymer, more preferably less than or equal to 40 mol%, even more preferably less than or equal to 30 mol%, typically less than or equal to 20 mol%.

[0075] Advantageously according to this first embodiment, the SBS block copolymer has a content of pendant vinyl groups in any range corresponding to the maximum and minimum values ​​mentioned above, and advantageously in the range from 5% to 20% by mole.

[0076] According to a second embodiment, the SBS block copolymer used according to the invention preferably has a content of pendant vinyl groups greater than or equal to 25 mol%, relative to the total number of moles of monomeric units of the SBS copolymer, more preferably greater than or equal to 30 mol%.

[0077] Preferably, according to this second embodiment, the SBS block copolymer used according to the invention preferably has a content of pendant vinyl groups of less than or equal to 50 mol%, relative to the total number of moles of monomeric units of the SBS copolymer, more preferably less than or equal to 45 mol%. Advantageously according to this second embodiment, the SBS block copolymer has a content of pendant vinyl groups in any range corresponding to the maximum and minimum values ​​mentioned above, and advantageously in the range from 35% to 45 mol%.

[0078] Preferably, the pendant vinyl groups are distributed along the B block of the SBS polymer in a statistical manner. This characteristic results directly from the process used for the synthesis of the copolymer.

[0079] The number of moles of monomeric units of the S blocks present in the SBS block copolymer represents, together, at least 15% of the total number of moles of monomeric units of the SBS copolymer, preferably at least 16% by mole.

[0080] Preferably, the number of moles of monomeric units of the S blocks of the SBS polymer represents, together, from 15% to 50% by mole, relative to the total quantity of moles of monomeric units of the SBS block copolymer, more preferably from 16% to 30% by mole, even more preferably from 16% to 25% by mole, and advantageously from 16% to 20% by mole. The number of moles of monomeric units of the S blocks of the SBS polymer can be determined by 13C NMR spectroscopy (Carbon Nuclear Magnetic Resonance).

[0081] Preferably, the content of monovinyl aromatic hydrocarbon monomer (advantageously styrene) of the SBS block copolymer, determined by 13C NMR spectroscopy (Carbon Nuclear Magnetic Resonance), is greater than or equal to 25% by mass, more preferably greater than or equal to 28% by mass, even more preferably greater than or equal to 30% by mass, relative to the total mass of the block copolymer of formula SBS.

[0082] Preferably, the content of monovinyl aromatic hydrocarbon monomer (advantageously styrene) of the SBS block copolymer, determined by 13C NMR spectroscopy (Carbon Nuclear Magnetic Resonance), ranges from 25% to 40% by mass, even more advantageously from 28% to 35% by mass, relative to the total mass of the SBS block copolymer.

[0083] Advantageously, SBS block elastomers are in an essentially non-hydrogenated form.

[0084] According to a particular embodiment, the block copolymer of formula SBS is obtained by coupling two block copolymers of formula S-B' in which the blocks S and B' are chosen to obtain an SBS block copolymer. The block B may therefore include a residue of a coupling agent, well known in the field in question. As examples of difunctional coupling agents, mention may be made of dibromoethane, diethyl adipate, divinylbenzene, dimethyldichlorosilane and methyl dichlorosilane.

[0085] Preferably, according to this particular embodiment, the efficiency of the coupling of the two block copolymers of formula S-B', measured by gel permeation chromatography, is greater than or equal to 50%, more preferably greater than or equal to 75%, even more preferably greater than or equal to 90% and advantageously greater than or equal to 95%.

[0086] Examples of SBS block copolymers which can be used in the compositions according to the invention, as well as their preparation processes, are described in particular in patent US 5,798,401, as well as in document WO 2007 / 058994 and by the applicant in patent application WO 201 1 / 013073.

[0087] It is possible that, in the bituminous compositions and the processes according to the invention, a single SBS block copolymer as described in the context of the invention is used, or that a mixture of SBS block copolymers as described in the context of the invention is used, or that one or more SBS block copolymer(s) as described in the context of the invention are used in combination with one or more other elastomers. According to a preferred variant, the matrix is ​​produced with only one or more, preferably a single, SBS elastomer. The latter preferably represents from 0.5 to 10% by mass, in particular from 1 to 6% by mass, and preferably from 1.5 to 4% by mass of the total mass of the bituminous composition. In the bituminous compositions according to the invention, said elastomer(s) is / are in a crosslinked form, but this does not affect the percentage that it / they represent within the composition.In other words, the percentages, before and after crosslinking, of the different components used for the preparation of the bituminous composition, are identical. When a mixture of elastomers, containing at least one elastomer other than the SBS elastomer as described in the context of the invention is used, the percentages of 0.5 to 10% by mass, in particular of 1 to 6% by mass, and preferably of 1.5 to 4% by mass given relative to the total mass of the bituminous composition, correspond to the total quantity of elastomers used (SBS + other elastomer(s)). In this case of use of a mixture of elastomers, containing at least one elastomer other than the SBS elastomers, the SBS elastomer represents at least 50%, preferably at least 70% by mass, and preferentially at least 90% of the total quantity of elastomers used (SBS + other elastomer(s)).

[0088] Preferably, the SBS elastomer(s) represent at least 80% by mass of the total quantity of elastomers, preferably at least 90% and preferentially at least 95% of the total quantity of elastomers present, if a mixture of elastomers is used to prepare the bituminous compositions according to the invention. In particular, it is possible for the mixture to contain a portion of S-B' used during the manufacture of the SBS elastomer by coupling, as explained previously.

[0089] The bitumen / polymer composition (optionally crosslinked) according to the invention preferably comprises from 0.1% to 20% by mass of elastomer, in particular of a copolymer of monovinyl aromatic hydrocarbon and conjugated diene, in particular of copolymer of styrene and butadiene, relative to the mass of the bitumen / polymer composition (crosslinked).

[0090] According to one embodiment, the bitumen / polymer composition (optionally crosslinked) of the invention comprises from 1% to 8% by mass of elastomer, in particular of a copolymer of monovinyl aromatic hydrocarbon and conjugated diene, in particular of copolymer of styrene and butadiene, relative to the mass of the crosslinked bitumen / polymer composition, more preferably from 2% to 5% by mass.

[0091] According to an alternative embodiment, the bitumen / polymer composition (optionally crosslinked) of the invention comprises from 5% to 20% by mass of elastomer, in particular of a copolymer of monovinyl aromatic hydrocarbon and conjugated diene, in particular of copolymer of styrene and butadiene, relative to the mass of the crosslinked bitumen / polymer composition, more preferably from 10% to 15% by mass.

[0092] Biochar

[0093] The bituminous composition according to the invention also comprises biochar.

[0094] According to the International Biochar Initiative (IBI), biochar is defined as a solid material obtained by thermochemical conversion, particularly by heating and / or pyrolysis, of biomass in an oxygen-limited environment, or even in the total absence of oxygen. In particular, the thermochemical conversion of biomass results in a complex mixture consisting mainly of hydrocarbon compounds of varying chain lengths. The mixture is then separated into different fractions based on their evaporation temperature. This produces a gaseous fraction, a (bio)fuel fraction, an oily fraction, and also a residue. This distillation residue then constitutes biochar.

[0095] Biochar differs from charcoal in its use (as a material of interest rather than as a fuel) and therefore in its environmental impact. Biochar thus constitutes a carbon sink, unlike charcoal, the combustion of which releases carbon dioxide into the atmosphere. In addition, biochar generally comes in the form of a powder, while charcoal comes in the form of lumps. The chemical and physical properties of biochar depend on several parameters, including the nature of the starting biomass ("feedstock" in English) but also on the parameters of the thermochemical conversion process, particularly the pyrolysis conditions.

[0096] The nature of the starting biomass is not particularly limited. Thus, the biochar present in the composition according to the invention can come from the thermochemical conversion of any type of biomass.

[0097] Typically, the biochar present in the composition according to the invention comes from the thermochemical conversion of biomass chosen from forest products; agricultural crop residues; animal waste; municipal waste and any of their mixtures.

[0098] Forest products include hardwoods (also called hardwoods) such as maple, oak, ash, cherry, walnut, apple, and pear; and softwoods such as conifers such as pine, spruce, and fir. Forest products may also include leaves, thorns, and fruit (acorns, pine cones, etc.).

[0099] Preferably, forest products are chosen from hardwoods, more preferably ash wood.

[0100] Crop residues include straw, such as corn straw, wheat straw or rice straw; bagasse (fibrous residue) obtained by grinding sugar cane; cereal husks; peanut shells; nut shells, such as almonds, Brazil nuts, cashew nuts, hazelnuts, pecans or walnuts.

[0101] For the purposes of the invention, the term "cereal husks" or "berry" (or even "basel") means a co-product derived from the processing of cereals and consisting of the glumes and glumes which enclose the grain. In other words, cereal husks constitute the envelope in which the grain of the cereals is contained.

[0102] Examples include corn husks, wheat husks, barley husks, sorghum husks, wheat husks, spelt husks and husks of any other cereal.

[0103] Preferably, the crop residues are chosen from cereal husks, nut shells, especially cashew nuts, and any of their mixtures.

[0104] Animal waste includes slurry, manure, and bedding from livestock, including poultry, pigs, and cattle. Municipal waste includes food waste, including organic waste such as peelings and coffee grounds, as well as municipal biosolids.

[0105] For the purposes of the invention, the term "municipal biosolids" or sewage sludge means the material resulting from the treatment of municipal wastewater and which is of sufficient quality to be recycled. It consists mainly of organic matter.

[0106] Preferably, municipal waste is chosen from food waste, coffee grounds and any of their mixtures.

[0107] According to a preferred embodiment, the biomass is chosen from hardwoods, in particular ash wood; cereal husks; nut shells, in particular cashew nuts; food waste; coffee grounds and any of their mixtures.

[0108] According to a further preferred embodiment, the biomass is chosen from ash wood, cereal husks, cashew nut shells, coffee grounds and any of their mixtures.

[0109] The process for converting biomass into biochar is not particularly limited. In particular, any thermochemical conversion process known to those skilled in the art can be implemented for the preparation of biochar usable in the compositions. Suitable conversion processes are for example described in Chapter 2 “Biochar for Maintaining Soil Health” of the book B. Giri, A. Varma (eds.), Soil Health!, Soil Biology 59. A. Tomczyk et al., “Biochar physichemical properties: pyrolysis temperature and feedstock kind effects”, Rev Environ Sci Biotechnol, February 5, 2020 also studies the impact of the choice of biomass and thermochemical conversion conditions on the nature of the final biochar.

[0110] The conversion of biomass into biochar is typically carried out at a temperature greater than or equal to 350°C, preferably ranging from 350°C to 900°C.

[0111] Preferably, the biochar has a high carbon content C, typically greater than 20% by mass, relative to the total mass of biochar, more preferably greater than or equal to 50%.

[0112] Advantageously, the biochar has a carbon content (also called total carbon content), determined by elemental analysis, ranging from 20% to 80% by mass, relative to the total mass of biochar, more preferably from 50% to 75% by mass.

[0113] For the purposes of the invention, the term "biogenic carbon" means the proportion of carbon present in the biochar coming directly from the biomass, in particular the proportion of carbon fixed by the initial biomass following a photosynthesis mechanism using CO2 from the air. Biogenic carbon is thus distinguished from fossil carbon, in particular by a difference in the ratio between the quantity of carbon 14 and carbon 13.

[0114] According to one embodiment, at least 80% of the carbon present in the biochar is biogenic, preferably at least 90%, more preferably at least 95%, advantageously at least 98%, more advantageously at least 99%.

[0115] Advantageously, 100% of the carbon present in biochar is biogenic.

[0116] The proportion of biogenic carbon in biochar is, for example, determined according to the EN 16640 standard, in particular the EN 16640:2017 standard.

[0117] Advantageously, the biochar has a biogenic carbon content, measured according to standard EN 16640, ranging from 20% to 80% by mass, relative to the total mass of biochar, more preferably from 50% to 75% by mass.

[0118] Preferably, the biochar has an organic carbon content, measured according to ISO 9686, ranging from 1% to 60% by mass, more preferably from 2% to 50% by mass, typically from 3% to 45% by mass.

[0119] Preferably, the biochar has an inorganic carbon content, measured according to ISO 9686, ranging from 0.1% to 20% by mass, more preferably from 0.2% to 15% by mass, typically from 0.5% to 10% by mass. Preferably, the biochar has a graphitic carbon content, measured according to ISO 9686, ranging from 5% to 90% by mass, more preferably from 7% to 80% by mass, typically from 10% to 75% by mass.

[0120] Preferably, the biochar has a low nitrogen N content, more preferably less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.1% to 10% by mass, typically from 0.5% to 5% by mass.

[0121] Preferably, the biochar has a low phosphorus P content, more preferably less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.01% to 10% by mass, typically from 0.05% to 7.5% by mass.

[0122] Preferably, the biochar has a low potassium K content, more preferably less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.01% to 10% by mass, typically from 0.05% to 7.0% by mass.

[0123] Preferably, the biochar has a low calcium Ca content, more preferably less than or equal to 15% by mass, relative to the total mass of biochar, even more preferably ranging from 0% to 15% by mass, typically from 0.01% to 10% by mass. Preferably, the biochar has a low magnesium Mg content, more preferably less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0% to 10% by mass, typically from 0.1% to 3% by mass.

[0124] The content of nitrogen N, phosphorus P, potassium K, calcium Ca and / or magnesium Mg in biochar is typically measured by elemental analysis.

[0125] Preferably, the biochar has an oxygen content O, measured by elemental analysis, ranging from 0.1% to 50% by mass, relative to the total mass of biochar, more preferably ranging from 0.5% to 40% by mass, typically from 2% to 35% by mass.

[0126] Preferably, the biochar has a hydrogen content H, measured by elemental analysis, ranging from 0.01% to 20% by mass, relative to the total mass of biochar, more preferably ranging from 0.05% to 15% by mass, typically from 0.1% to 8% by mass.

[0127] According to one embodiment, the ratio between the mass of hydrogen present in the biochar and the total mass of organic carbon present in the biochar ranges from 0.01 to 5, preferably from 0.015 to 3, more preferably from 0.02 to 2.

[0128] According to one embodiment, the ratio between the mass of oxygen present in the biochar and the total mass of carbon (total carbon) present in the biochar ranges from 0.01 to 5, preferably from 0.02 to 3, more preferably from 0.04 to 1.

[0129] According to one embodiment, the biochar is porous, preferably of open porosity.

[0130] For the purposes of the invention, "open porosity" means that the pores of the material are connected to each other in such a way as to form a continuous network. All of the pores of the material are therefore accessible to water.

[0131] Preferably, the biochar has a porosity ranging from 10% to 90% by volume, more preferably from 30% to 85%, even more preferably from 50% to 85%.

[0132] Methods for measuring the porosity of a biochar are known to those skilled in the art. These include, in particular, the methods described in CE Brewer, BIOMASS AND BIOENERGY, 66, 2014, 176-185.

[0133] Advantageously, the biochar has a specific surface area, measured according to the BET method defined in the ISO 9277 standard, ranging from 1.5 m 2 / g at 500 m 2 / g, more preferably 5 m 2 / g at 450 m 2 / g, even more preferably 10 m 2 / g at 400 m 2 / g. Preferably, the biochar has a high pH, ​​typically greater than or equal to 5, more preferably ranging from 5 to 12, advantageously ranging from 6 to 10. According to one embodiment, the biochar has a cation exchange capacity ranging from 1 cmol.Kg -1 at 100 cmol.Kg -1 , preferably 1.5 cmol.Kg -1 at 80 cmol.Kg -1 , more preferably 2 cmol.Kg -1 at 70 cmol.Kg -1 .

[0134] Methods for measuring the cation exchange capacity of a biochar are known to those skilled in the art. Examples include the Metson method and the Bower method.

[0135] According to one embodiment, the surface of the biochar is functionalized.

[0136] Preferably, according to this embodiment, the surface of the biochar comprises at least one functional group chosen from: a phenol group, a lactone group (cyclic ester), a carboxylic acid group, a carboxylic anhydride group, a peroxide group, an amine group, a quinone group, a chromene group, an ether group, a pyrone group and any combination thereof.

[0137] The crosslinked bitumen / polymer composition according to the invention preferably comprises from 0.1% to 50% by mass of biochar, relative to the mass of the bitumen / polymer composition, more preferably from 0.5% to 30%, even more preferably from 1% to 15%.

[0138] Additives

[0139] According to one embodiment, the bitumen / polymer composition according to the invention further comprises one or more additional additive(s).

[0140] These additional additives are known to those skilled in the art. By way of example, the following additives may be mentioned in particular: a) adhesion promoters and / or surfactants. They are generally chosen from alkylamine derivatives, alkylpolyamine derivatives, alkylamidopolyamine derivatives and quaternary ammonium salt derivatives, taken alone or as a mixture. The amount of adhesion promoters and / or surfactants present in the bitumen / polymer composition is, for example, between 0.2% and 2% by weight, preferably between 0.5% and 1% by weight, relative to the total mass of the bitumen / polymer composition. b) waxes of animal or vegetable origin or hydrocarbon waxes, in particular long-chain hydrocarbon waxes, for example polyethylene waxes or paraffins, optionally oxidized. Amide waxes, such as ethylene bis(stearamide),may also be added. c) paraffins having chain lengths of 30 to 120 carbon atoms (C30 to C120). The paraffins are chosen from polyalkylenes. Preferably, the paraffins are polymethylene paraffins and polyethylene paraffins. These paraffins may be of petroleum origin or may come from the chemical industry. Preferably, the paraffins are synthetic paraffins resulting from the conversion of biomass and / or natural gas. d) fluxes, such as oils based on animal and / or vegetable fatty substances or hydrocarbon oils of petroleum origin. The oils of animal and / or vegetable origin may be in the form of free fatty acids, triglycerides, diglycerides, monoglycerides or in esterified form, for example in the form of methyl ester. e) resins of vegetable origin, such as rosins. (f) anti-foam additives,in particular (but not limited to) chosen from polysiloxanes, oxyalkylated polysiloxanes and fatty acid amides derived from vegetable or animal oils. g) detergent additives and / or corrosion inhibitors, in particular (but not limited to) chosen from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkylpolyamines, polyetheramines and imidazolines. h) slip agents or anti-wear agents, in particular (but not limited to) chosen from the group consisting of fatty acids and their ester or amide derivatives, in particular glyceryl monooleate, and mono- and polycyclic carboxylic acid derivatives. i) crystallization modifying additives, paraffin deposit inhibiting additives, pour point lowering additives; low temperature rheology modifiers,such as ethylene / vinyl acetate (EVA) and / or ethylene / vinyl propionate (EVP) copolymers, ethylene / vinyl acetate / vinyl versatate (EA / AA / EOVA) terpolymers; ethylene / vinyl acetate / alkyl acrylate terpolymers; graft-modified EVA copolymers; polyacrylates; acrylate / vinyl acetate / maleic anhydride terpolymers; amidated maleic anhydride / alkyl (meth)acrylate copolymers obtainable by reacting a maleic anhydride / alkyl (meth)acrylate copolymer and an alkylamine or polyalkylamine having a hydrocarbon chain of 4 to 30 carbon atoms, preferably 12 to 24 carbon atoms; amidated α-olefin / maleic anhydride copolymers obtainable by reaction of an α-olefin / maleic anhydride copolymer and an alkylamine or polyalkylamine, the α-olefin being able to be chosen from C10-C50 α-olefins, preferably C16-C20 α-olefins,and the alkylamine or polyalkylamine advantageously having a hydrocarbon chain of 4 to 30 carbon atoms, preferably 12 to 24 carbon atoms. j) antioxidants, for example of the hindered phenolic type or of the amino type, of the alkylated para-phenylenediamine type. k) metal passivators. l) acidity neutralizers. m) additives for lowering the mixing temperature of asphalts and coated materials, those for improving the adhesion of bituminous binders to fillers and aggregates, such as, for example, polyisobutylene succinimides. n) acids, such as polyphosphoric acid, or diacids, in particular fatty diacids.,

[0141] The additives are used in quantities well known to those skilled in the art, depending on the nature of the additive, the bituminous base and the expected properties.

[0142] Preferably, when present, the content of additional additives varies from 0.1% to 10% by mass, preferably from 0.5% to 5% by mass, more preferably from 0.5% to 2.5% by mass, relative to the total mass of the bituminous composition of the invention.

[0143] Compositions

[0144] Preferably, the bituminous composition of the invention comprises, preferably consists essentially of, even more preferably consists of:

[0145] - from 40% to 99.9% by mass of bitumen, from 0.1% to 20% by mass of one or more elastomer(s), preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0146] - from 0.1% to 50% by mass of biochar, and optionally, from 0.1% to 10% by mass of additional additive(s) as described above, relative to the total mass of the bituminous composition.

[0147] According to a first embodiment, the bituminous composition of the invention comprises, preferably consists essentially of, even more preferably consists of:

[0148] - from 50% to 99% by mass of bitumen, from 1% to 8% by mass of one or more elastomer(s), preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0149] - from 0.5% to 30% by mass of biochar, and optionally, from 0.5% to 5% by mass of additional additive(s) as described above, relative to the total mass of the bituminous composition.

[0150] Preferably, according to this first embodiment, the bituminous composition of the invention comprises, preferably consists essentially of, even more preferably consists of:

[0151] - from 60% to 95% by mass of bitumen,

[0152] - from 2% to 5% by mass of one or more elastomer(s), preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0153] - from 1% to 15% by mass of biochar, and optionally, from 0.5% to 2.5% by mass of additional additive(s) as described above, relative to the total mass of the bituminous composition.

[0154] According to a second embodiment, the bituminous composition of the invention comprises, preferably consists essentially of, even more preferably consists of:

[0155] - from 50% to 99% by mass of bitumen, from 5% to 20% by mass of one or more elastomer(s), preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0156] - from 0.5% to 30% by mass of biochar, and optionally, from 0.5% to 5% by mass of additional additive(s) as described above, relative to the total mass of the bituminous composition.

[0157] Preferably, according to this second embodiment, the bituminous composition of the invention comprises, preferably consists essentially of, even more preferably of:

[0158] - from 60% to 95% by mass of bitumen, from 10% to 15% by mass of one or more elastomer(s), preferably chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0159] - from 1% to 15% by mass of biochar, and optionally, from 0.5% to 2.5% by mass of additional additive(s) as described above, relative to the total mass of the bituminous composition.

[0160] The bituminous composition according to the invention is homogeneous. For the purposes of the invention, the term “homogeneous” means that the various components of the composition, namely the elastomer, the biochar and any additives, are distributed uniformly in the bituminous matrix.

[0161] According to one embodiment, the composition according to the invention has a penetrability at 25°C, measured according to standard EN 1426, lower than the penetrability at 25°C of the same composition free of biochar.

[0162] Preferably, the composition according to the invention has a penetrability at 25°C, measured according to standard EN 1426, ranging from 25 to 45 1 / 10 mm, more preferably from 30 to 40 1 / 10 mm.

[0163] According to one embodiment, the composition according to the invention has a ring and ball softening temperature, measured according to standard EN 1427, higher than the ring and ball softening temperature of the same composition free of biochar.

[0164] Preferably, the composition according to the invention has a ring and ball softening temperature, measured according to standard EN 1427, greater than 60°C, more preferably greater than or equal to 65°C, advantageously ranging from 65°C to 90°C, typically ranging from 65°C to 80°C.

[0165] According to one embodiment, the composition according to the invention has an energy at 400%, measured according to standard NE EN 13587, greater than the energy at 400% of the same composition free of biochar.

[0166] Preferably, the composition according to the invention has an energy at 400%, measured according to standard NE EN 13587, greater than or equal to 20 J / cm 3, more preferably greater than or equal to 21 J / cm 3 , advantageously ranging from 20 J / cm 3 at 50 J / cm 3 , typically ranging from 21 J / cm 3 at 30 J / cm 3 .

[0167] According to one embodiment, the composition according to the invention has a threshold stress, measured according to standard NE EN 13587, greater than the threshold stress of the same composition free of biochar.

[0168] Preferably, the composition according to the invention has a threshold stress, measured according to standard NE EN 13587, greater than or equal to 2 Mpa, more preferably greater than or equal to 2.2 Mpa, advantageously ranging from 2.2 Mpa to 3 Mpa, typically ranging from 2.3 Mpa to 2.8 Mpa.

[0169] Process for preparing a bituminous composition according to the invention

[0170] The bituminous compositions of the invention may be prepared by any method known to those skilled in the art. Generally, these methods comprise mixing the components and heating the resulting mixture. The bitumen may be heated before mixing. Usually, the bitumen is heated before mixing, and the additive(s) are added to the bitumen without having been heated beforehand. According to a particular embodiment of the invention, a bitumen composition is prepared by bringing into contact:

[0171] - at least one bitumen base;

[0172] - at least one elastomer as defined above,

[0173] - biochar, preferably as defined above;

[0174] - possibly one or more other additive(s), in particular one or more additional additive(s) as described above.

[0175] In particular, the mixing of the following components is carried out, under heating and stirring:

[0176] - at least one bitumen base,

[0177] - at least one elastomer as defined above, chosen from copolymers of a monovinyl aromatic hydrocarbon and a conjugated diene

[0178] - biochar, preferably as defined above;

[0179] - possibly one or more other additive(s), in particular one or more additional additive(s) as described above.

[0180] The mixture of bitumen, elastomer, biochar, or even the other additive(s) present, can be carried out at a temperature ranging from 90 to 230°C, preferably from 120 to 200°C, and preferentially from 150 to 180°C.

[0181] Such a mixture is carried out under agitation, so as to facilitate the dispersion and good distribution of the biochar (and the elastomer) in the bitumen which will constitute the matrix of the composition, possibly in association with the additional additive(s). The conditions are adapted to lead to the obtaining of a homogeneous mixture and to the distribution of the biochar and the elastomer. Conventionally, the person skilled in the art will adjust the time and power of the agitation, as well as the mixing temperature, in particular according to the bitumen, the elastomer and the precise nature of the biochar to have a molten mixture. Advantageously, the mixing is carried out in such a way as to promote a good distribution of the biochar and the elastomer in the final bituminous composition obtained.

[0182] In general, and in a manner known to those skilled in the art, the bitumen or mixture of bitumens used for the manufacture of the composition is previously heated and stirred, before incorporation of the other constituents of the composition. The incorporation of the biochar and the elastomer is, in general, carried out, while the bitumen is maintained at a temperature belonging to the range from 90 to 230°C, preferably to the range from 120 to 200°C, and preferentially to the range from 150 to 180°C.

[0183] The components can be introduced simultaneously or in sequence. Heating is maintained throughout the process, and the heating temperature can be modulated during the process. Agitation can be maintained or interrupted intermittently as needed, or modulated during the process.

[0184] According to particular embodiments, the method according to the invention comprises a homogenization step which makes it possible, in particular, to distribute the biochar and the elastomer in said composition. Such a step is in particular a step of mixing the different constituents, with stirring at a speed of 100 to 600 rpm, preferably 200 to 400 rpm and for a duration of 2 to 30 hours, preferably 6 to 24 hours, while the mixture is heated to a temperature belonging to the range of 90 to 230°C, preferably to the range of 120 to 200°C, and preferably to the range of 150 to 180°C.

[0185] In the process according to the invention, one or more bitumen(s), one or more biochar(s), one or more elastomer(s), or even one or more additional additive(s) are used, corresponding to the descriptions given previously in the corresponding parts. The crosslinked elastomers are introduced in crosslinkable form into the compositions according to the invention and crosslinked in situ.

[0186] Of course, in the process, the quantities used of bitumen, elastomer(s), biochar, or even additional additive(s) possibly present, will be adjusted by those skilled in the art to ultimately obtain the desired quantities in the final composition, and in particular those mentioned in the previous part relating to the compositions according to the invention.

[0187] According to one embodiment, the composition of the invention comprises a significant proportion of bio-sourced, recycled or waste-derived materials. It can therefore have a high eco-material index. The eco-material index is defined by the following equation:

[0188] Eco-material index = 100% - [% of non-biosourced, non-biodegradable, non-recycled or non-waste materials], the percentages being expressed in mass, relative to the total mass of the composition.

[0189] According to one embodiment, the composition has an eco-material content of at least 5%, preferably at least 10%, preferentially at least 15%.

[0190] Advantageously, the bituminous composition of the invention has a content of bio-sourced compounds, measured according to the ASTM D6866 standard, greater than or equal to 5% by mass, relative to the total mass of the composition, preferably greater than or equal to 10% by mass, more preferably greater than or equal to 15% by mass. For the purposes of the invention, the term "bio-sourced compounds" means a material derived at least in part from biomass resources. Biomass resources are organic materials available in a renewable or recurring manner, such as crop residues, wood residues, grasses and aquatic plants. Corn ethanol is a well-known example of a bio-sourced material derived from biomass resources.

[0191] The characteristics described in the preceding sections also apply to the preparation processes according to the invention. Thus, the components used in the preparation process will preferably be chosen from those previously described and introduced in proportions making it possible to produce the quantities given for the description of the bituminous compositions according to the invention.

[0192] The bituminous compositions capable of being obtained by such processes also form an integral part of the invention.

[0193] Applications

[0194] Various uses of the bituminous compositions according to the invention are envisaged. In particular, the bituminous compositions according to the invention can be used as a bituminous binder.

[0195] The bituminous binder or bituminous composition according to the invention can in turn be used to prepare an association with aggregates, in particular road aggregates. With regard to road applications, the invention relates in particular to bituminous coatings as materials for the construction and maintenance of road surfaces and their surfacing, as well as for carrying out all road works.

[0196] By bituminous mix is ​​meant a mixture of a bituminous binder with aggregates and possibly mineral and / or synthetic fillers. The bituminous mix comprises a bituminous binder according to the invention, and possibly mineral and / or synthetic fillers, preferably chosen from fines, sand, gravel and recycled millings.

[0197] Aggregates are mineral and / or synthetic aggregates, in particular, recycled millings, with dimensions greater than 2 mm, preferably between 2 mm and 20 mm.

[0198] The invention also relates to a process for preparing a bituminous coating comprising the hot mixing of a bituminous composition according to the invention, with aggregates, and optionally mineral and / or synthetic fillers.

[0199] The bituminous binder according to the invention can advantageously be used to prepare a surface coating, a hot mix, a cold mix, a cold-poured mix or an emulsion gravel. With regard to road applications, the invention also relates to asphalts as materials for manufacturing and covering pavements.

[0200] Asphalt is understood to mean a mixture of bituminous binder with mineral and / or synthetic fillers. An asphalt comprises a bituminous composition as described in the context of the invention and mineral fillers such as fines, sand or gravel and / or synthetic fillers. The mineral fillers consist of fines (particles with dimensions less than 0.063 mm), sand (particles with dimensions between 0.063 mm and 2 mm) and possibly gravel (particles with dimensions greater than 2 mm, preferably between 2 mm and 4 mm). Asphalts have 100% compaction and are mainly used to manufacture and cover sidewalks, whereas asphalts have a compaction of less than 100% and are used to manufacture roads. Unlike asphalts, asphalts are not compacted by roller during their installation.

[0201] The invention also relates to a process for preparing an asphalt comprising the hot mixing of a bituminous composition according to the invention, with mineral and / or synthetic fillers.

[0202] Another aspect of the invention relates to the use of a bituminous composition in various industrial applications, in particular for preparing a waterproofing coating, a membrane or an impregnation layer. Industrial applications of the bituminous compositions include the manufacture of waterproofing membranes, noise-reducing membranes, insulation membranes, surface coverings, carpet tiles, impregnation layers.

[0203] The invention also relates to the use of biochar in a bituminous composition, preferably in an optionally crosslinked bitumen / polymer composition, to reduce the carbon footprint of said composition.

[0204] For the purposes of the invention, the term "carbon footprint" of a product means the quantity of carbon (generally expressed in kg of CO2 equivalent per kg of product) required for the preparation of said product, this quantity of carbon equivalent taking into account both energy consumption, particularly related to heating, and raw materials. The carbon footprint of a product is typically determined according to any of the ISO 14040 and ISO 14044 standards.

[0205] Preferably, the use of biochar according to the invention makes it possible to reduce by at least 10% the carbon footprint of a bituminous composition, in particular of a bitumen / polymer composition (crosslinked or not), compared to the same composition free of biochar, more preferably at least 20%, even more preferably at least 30%, advantageously at least 80%, more advantageously at least 90%, typically at least 95%.

[0206] According to one embodiment, the use of biochar according to the invention makes it possible to reduce the carbon footprint of a bituminous composition by up to 50%, in particular of a bitumen / polymer composition (crosslinked or not), compared to the same composition free of biochar, more preferably up to 60%, even more preferably up to 70%, advantageously up to 80%, more advantageously up to 90%, typically up to 95%.

[0207] In particular, the incorporation of biochar at a content of 5% by mass, relative to the total mass of the bitumen / polymer composition (crosslinked or not), makes it possible to reduce the carbon footprint of the bituminous composition by up to 60%, compared to the same composition without biochar.

[0208] More specifically, the incorporation of biochar at a content of 10% by mass, relative to the total mass of the bitumen / polymer composition (crosslinked or not), makes it possible to reduce the carbon footprint of the bituminous composition by up to 100%, compared to the same composition without biochar. In other words, the bituminous composition thus obtained is carbon neutral.

[0209] The invention also relates to the use of biochar in a bituminous composition, preferably in an optionally crosslinked bitumen / polymer composition, to reduce the penetrability at 25°C, in particular measured according to standard EN 1426, of said composition.

[0210] The invention also relates to the use of biochar in a bituminous composition, preferably in an optionally crosslinked bitumen / polymer composition, to increase the ring and ball softening temperature, in particular measured according to standard EN 1427, of said composition.

[0211] The invention also relates to the use of biochar in a bituminous composition, preferably in an optionally crosslinked bitumen / polymer composition, to increase the energy to 400%, in particular measured according to standard NF EN 13587, of said composition.

[0212] The invention finally relates to the use of biochar in a bituminous composition, preferably in an optionally crosslinked bitumen / polymer composition, to increase the threshold stress, in particular measured according to standard NF EN 13587, of said composition. EXAMPLES

[0213] Evaluation of bituminous compositions

[0214] In the following examples, the bituminous compositions are evaluated by:

[0215] - measurement of needle penetrability at 25°C (abbreviation: P25), according to standard EN 1426, the results being expressed in 1 / 10 mm,

[0216] - measurement of the ring-ball softening temperature (abbreviation: TBA), according to standard EN 1427, the results being expressed in °C,

[0217] - mechanical properties (stress at maximum elongation, threshold elongation, maximum elongation, energy at 400%, total energy), measured according to standard NE EN 13587.

[0218] Raw materials

[0219] The examples were made with the following raw materials:

[0220] Bitumen Base (B): grade 35 / 50 bitumen with a P25 penetrability of 40 1 / 10 mm and a TBA of 52°C, commercially available from TotalEnergies under the AZALT® brand.

[0221] SBS heat-crosslinkable elastomer (E): styrene / butadiene / styrene (SBS) block copolymer, comprising 30.5% by mass of styrene and 69.5% by mass of butadiene. The content of pendant vinyl groups, resulting from the 1,2-addition polymerization of butadiene, is 27.8% by mass relative to the total mass of the copolymer. The copolymer has a weight-average molecular weight (Mw) of 142,500 Daltons and a polydispersity index Ip of 1.09. This copolymer is commercially available from KRATON under the name D1192.

[0222] SB (E) heat-crosslinkable elastomer: styrene / butadiene copolymer comprising 25% styrene, of which 17.5% is in the form of polystyrene blocks. This copolymer is commercially available from Dynasol under the name Solprene S1205.

[0223] EAG (E) heat-crosslinkable elastomer: ethylene / ethyl acrylate / glycidyl methacrylate terpolymer in mass proportions, determined by proton nuclear magnetic resonance, of 74 / 16 / 10 respectively and having a melt index MER (190°C / 2.16 kg) of 8g / 10min, calculated according to ASTM D1238- ISO1 133. This polymer is commercially available under the name Elvaloy® 5170P from the Dupont company.

[0224] SBS / SB heat-crosslinkable elastomer (E): blend based on styrene / butadiene (SB) and styrene / butadiene / styrene (SBS) block copolymer. The monovinyl aromatic hydrocarbon monomer content is 15.8 mol% relative to the total number of polymer moles. The mass-average molecular weight of the blend is 285,000 g / mol. This copolymer is commercially available from Kraton under the name MD246.

[0225] Biochar: This is a 100% plant-based biochar made from hardwood.

[0226] Preparation of compositions

[0227] Compositions C1, C2 and C3 according to the invention, and comparative compositions C4, C5 and C6 are prepared according to the following protocol:

[0228] The pure bitumen is first heated to 160°C in an oven, then transferred to a 3L reactor in which it is heated for 1 hour at 180°C.

[0229] The elastomer and biochar are then added and the mixture ground for 15 min at 6,000 rpm, at a temperature between 150°C and 170°C, using a high shear rotorstator (Silverson).

[0230] The reactor is then placed under mechanical stirring at 300 rpm for 24 hours at 180°C.

[0231] This gives the thermo-crosslinked matrix of the bituminous composition.

[0232] The details of the compositions are given in Table 1 below. The contents are given by mass, relative to the total mass of the crosslinked bitumen / polymer composition. Properties of compositions

[0233] The properties of the compositions were evaluated according to the protocols defined above. The results are summarized in Table 2 below. Compositions C1, C2 and C3 thus have properties equivalent to a bituminous composition not including biochar. Thus, the addition of rosin does not in any way deteriorate the performance of the bituminous compositions when it is introduced with an elastomer comprising an SBS unit.

[0234] Additionally, compositions C4 and C6 do not exhibit 400% energy values ​​because these compositions do not support sufficient traction to reach the 400% threshold.

Claims

CLAIMS 1. Bituminous composition comprising: - at least one bitumen base, - at least one elastomer comprising at least one styrene-butadiene-styrene unit, - biochar.

2. Bituminous composition according to claim 1, in which the biochar is derived from thermochemical conversion of biomass chosen from forest products; crop residues; animal waste; municipal waste and any of their mixtures.

3. Bituminous composition according to claim 1 or claim 2, in which the biochar is derived from the thermochemical conversion of biomass chosen from hardwoods, in particular ash wood; cereal husks; nut shells, in particular cashew nuts; food waste; coffee grounds and any of their mixtures.

4. Crosslinked bitumen / polymer composition, obtained by crosslinking, in particular chemical or thermal, of a bituminous composition according to any one of the preceding claims.

5. Composition according to any one of claims 1 to 4, having a reduced carbon footprint, compared to the same composition free of biochar.

6. Composition according to any one of the preceding claims, having a content of biosourced compounds, measured according to the ASTM D6866 standard, greater than or equal to 5% by mass, relative to the total mass of the composition, preferably greater than or equal to 10% by mass, more preferably greater than or equal to 15% by mass.

7. Process for preparing a bitumen / polymer composition according to any one of the preceding claims, this process comprising: 1) bringing the following components into contact: - at least one bitumen base, - at least one elastomer, and - biochar, 2) mixing the components.

8. Preparation process according to claim 7, wherein the mixing of the components is carried out under heating and stirring, preferably at a temperature ranging from 90°C to 230°C, more preferably from 120°C to 200°C, even more preferably from 150°C to 180°C.

9. Use of a bituminous composition according to any one of claims 1 to 6, for preparing a surface coating, a hot mix, a cold mix, a cold-poured mix, a gravel emulsion or a wearing course, said binder being associated with aggregates and / or recycled millings.

10. Bituminous coating comprising a bituminous composition according to any one of claims 1 to 6, mixed with aggregates and / or recycled millings, and optionally mineral and / or synthetic fillers.

11. Asphalt comprising a bituminous composition according to any one of claims 1 to 6, mixed with mineral and / or synthetic fillers.

12. Use of a bituminous composition according to any one of claims 1 to 6, for preparing a waterproofing coating, a membrane or an impregnation layer.

13. Use in a bitumen / polymer composition, optionally crosslinked, of biochar to reduce the carbon footprint of said bituminous composition.

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