Bituminous compositions modified by incorporation of alkali hydroxide and trapping CO2, associated processes and uses

Abstract

Bituminous compositions modified by incorporation of alkali hydroxide and trapping CO2, associated methods and uses Contents of the abstract. The present invention relates to a bituminous composition comprising a bitumen base modified by incorporation of an alkali hydroxide characterized in that CO2 is trapped in said bituminous composition and represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, of the mass of bitumen base and the mass of the bituminous composition is stable at 25°C and under 1013.25 hPa, over a period Ps of at least 10 hours, preferably at least 15 hours. The invention also relates to a process for preparing such compositions and their uses, in particular for the manufacture of coated materials or asphalts. Figure for the abstract: none.

Description

Title of the invention: Bituminous compositions modified by incorporation of alkali hydroxide and trapping CO 2 , associated processes and uses Technical field

[0001] The present invention relates to the technical field of bitumens. More specifically, it relates to bituminous compositions for trapping CO2, and, consequently, offering the possibility of reducing the quantities of CO2 emitted into the atmosphere. The invention also relates to the processes for preparing such compositions, as well as their uses in the road sector and in the industrial sector. Prior art

[0002] CO2 is a greenhouse gas. Thus, the emission of CO2 into the atmosphere contributes to global warming. To act in favor of sustainable development and reduce global warming, solutions are being sought to reduce the amount of CO2 released into the atmosphere. Ways to capture the CO2 produced by various human activities are therefore of great interest.

[0003] The applicant has attempted to trap CO2 in bituminous compositions, but the tests carried out presented in the examples show that the CO2 tends to be released, after trapping in the bitumen, and that there is a real challenge in being able to stabilize part of the CO2 which can be stored in the bitumen, so that the latter can at least be partially stored in the long term in the bitumen.

[0004] In this context, the applicant proposes new bituminous compositions for storing CO2 sustainably, processes for obtaining such compositions and their use in the road and industrial fields. Statement of the invention

[0005] The subject of the invention is a bituminous composition comprising a bitumen base modified by incorporation of an alkali hydroxide characterized in that CO2 is trapped in said bituminous composition and represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, of the mass of bitumen base and the mass of the bituminous composition is stable at 25°C and under 1013.25 hPa, over a period Ps of at least 10 hours, preferably at least 15 hours.

[0006] The mass of the bituminous composition is considered to be stable over a given period, in particular over a period Ps of 10 hours to 100 hours, in particular from 19 to 91 hours, and typically from 19 hours, if this mass does not decrease by more than 2%, preferably this mass does not decrease by more than 1%, and preferably does not decrease by more than 0.5%, and even more preferably does not decrease by more than 0.05% compared to the initial mass of the composition, that is to say its mass at the start of the period considered. The stability of a composition as it is at a given time t can therefore be evaluated, by measuring the mass of the latter at this time t, then at this time t+19 hours typically, or more generally t + the evaluation period Ps.In other words, the mass of a bituminous composition is qualified as stable, if the mass mPs of the bituminous composition at the end of the evaluation period Ps (t=10 to 100 hours, in particular = 19 to 91 hours, and typically = 19 hours) is greater than or equal to its mass mo at the start of the evaluation period (t=0) - 2%, preferably is greater than or equal to m0 - 1%, is greater than or equal to m0 - 0.5%, and even more preferably is greater than or equal to m0 - 0.05%.

[0007] In the context of the invention, the stability of the mass of the bituminous composition is evaluated, leaving a bituminous composition, at 25°C and under atmospheric pressure (i.e. under a pressure of 1013.25 hPa). Under these conditions, the atmosphere in which the bituminous composition is located has no influence. However, typically, the stability is evaluated under ambient air. In the context of the invention, it has been found that when an alkali hydroxide has been incorporated into a bitumen base, it is then possible to incorporate CO2 into the matrix obtained formed from the bitumen base / alkali hydroxide mixture and, without there then being a total release of the incorporated CO2.Indeed, even if immediately after the incorporation of CO2, a part of the latter tends to redissipate into the ambient atmosphere, after a certain time, this release ceases, which is materialized by a stabilization of the mass of the bituminous composition obtained. Thus, the stability of the mass of the bituminous composition reflects the fact that the quantity of CO2 trapped in said composition is stabilized. The inventors have demonstrated, within the framework of the invention, that this stabilization occurs while a significant part of the mass of CO2 initially incorporated is still trapped within the bituminous composition. Within the framework of the invention, we speak indifferently of trapped CO2 or incorporated CO2.Trapped CO2 or incorporated CO2 means that the CO2 has been incorporated into the bituminous composition and remains present in the latter, either in the initial CO2 form which has diffused into the bituminous composition, or in a modified form due to an interaction or reaction with one of the components present in the bituminous composition. Whatever the form in which the CO2 is present, in the context of the invention, when it is a question of mass of CO2, it is the mass of incorporated CO2, even if the latter is found. in a form which has reacted with alkali hydroxide, in particular.

[0008] In particular, the CO2 was trapped in the bituminous composition, following a trapping step, in particular carried out by placing said bitumen base modified by incorporation of an alkali hydroxide, in a CO2 pressurized enclosure, followed by a step of releasing a portion of the trapped CO2, until the mass of the bituminous composition obtained stabilizes, this stabilization occurring in particular, 3 hours or more after the end of the trapping step, in particular 5 to 10 hours after the end of the trapping step.

[0009] In particular, the incorporation of CO2, during this trapping step, is carried out by placing the modified bitumen base in an enclosure under CO2 pressure, the enclosure being maintained at a temperature ranging from 10 to 200°C, preferably ranging from 20 to 160°C, and preferentially ranging from 25 to 160°C, or even 80 to 160°C, the CO2 pressure being chosen in particular in the range from 5.103 to 8.104 hPa, preferably in the range from 5.103 to 5.104 hPa, and preferentially in the range from 1.104 to 3.104 hPa.

[0010] Once the mass of the bituminous composition has been stabilized, the latter remains stable if the bituminous composition is maintained at 25°C and under atmospheric pressure. Typically, within the scope of the invention, the bituminous compositions comprising a bitumen base in which an alkali hydroxide has been incorporated have a mass which is stable at 25°C and under 1013.25 hPa, over a period Ps of at least 10 hours, preferably at least 15 hours, and typically 19 hours. In other words, over a period Ps of at least 10 hours, preferably at least 15 hours, and typically 19 hours, the mass of the composition does not decrease by more than 2%, preferably does not decrease by more than 1%, and preferably does not decrease by more than 0.5%, and even more preferably does not decrease by more than 0.05% relative to the initial mass of the composition, at the start of the period Ps considered.A bituminous composition according to the invention has a stable mass, while it has a quantity of CO2 which has been incorporated into the bituminous composition and which remains trapped in said bituminous composition. This quantity of CO2 represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass of the mass of the bitumen base, and preferentially from 0.5 to 3% by mass of the mass of the bitumen base, and even more preferably from 0.5 to 2% by mass or from 0.5 to 1.5% by mass or from 0.7 to 2% by mass, of the mass of the bitumen base. The quantity of CO2 can be determined by weighing.

[0011] In the context of the invention, the masses can be determined by weighing, with a precision balance, in particular 0.0001 g ready (for example Sartorius Practum 224-1S balance). In particular, the weighings are carried out at 25 °C and under atmospheric pressure (1013.25 hPa).

[0012] The bituminous compositions according to the invention are obtained by placing an original bituminous composition (also called modified bitumen base) under CO2 pressure. The original bituminous composition comprises all the components of the desired bituminous composition, with the exception of CO2. In particular, the incorporation of CO2 is carried out by placing such an original bituminous composition in a CO2 pressure chamber, the chamber being maintained at a temperature ranging from 10 to 200°C, preferably from 20 to 160°C, and preferentially from 25 to 160°C, or even 80 to 160°C, the CO2 pressure being chosen in particular in the range from 5.103 to 8.104 hPa (equivalent to 5-80 bars), preferably in the range from 5.103 to 5.104 hPa, and preferentially in the range from 1.104 to 3.104 hPa.The mass of CO2 incorporated in a bituminous composition, regardless of the form in which the CO2 is present in said composition, corresponds to the difference between the mass of said bituminous composition and the mass of the same original bituminous composition. The mass of CO2 incorporated can be monitored over time, by monitoring the mass of the bituminous composition. At the end of the CO2 trapping step, in particular if the trapping is carried out until the composition is saturated with CO2, when the bituminous composition obtained comprising trapped CO2 is then stored at 25°C and under atmospheric pressure, there is first of all a phase of release of a portion of the incorporated CO2, which results in a loss of mass of the composition. Then, this release ceases, even though a portion of the CO2 remains trapped in the bituminous composition.This stabilization of the CO2 incorporated in the bituminous composition is materialized by a stabilization of the mass of the bituminous composition. It is, in particular, these stabilized bituminous compositions which are the subject of the invention. In the bituminous compositions according to the invention, it is a question of trapped CO2, but within the composition the trapped CO2, or at least a part of the trapped CO2, may not be in the CO2 form, but may have reacted with one of the components present or incorporated in the composition, and in particular be in the form of one or more reaction products with the alkali hydroxide.

[0013] Thus, the period Ps over which the mass of the bituminous composition according to the invention is stable starts, after a release phase Pr, during which a portion of the trapped CO2 is released from the bituminous composition. This release phase Pr is, most often, 5 to 10 hours, and typically 5 hours, after the end of the CO2 trapping step. The end of the CO2 trapping step corresponds, in particular, to the moment when the bituminous composition is no longer under CO2 pressure. During this release phase Pr following the CO2 trapping, the bituminous composition may be placed at 25°C and under 1013.25 hPa. It is also possible for the bituminous composition to be subjected to heating. during this release phase Pr, which will have the effect of accelerating the release of part of the CO2 and therefore reducing the duration of the release phase. Once the release phase Pr is complete, the remaining CO2 remains trapped within the bituminous composition, under so-called standard storage conditions (at 25°C and under 1013.25 hPa), which results in a stabilization of the mass of the bituminous composition. The mass of the bituminous composition is understood as the mass of all the components present (in particular the bitumen base, the alkali hydroxide introduced, and any other components present) but also of the CO2 trapped in the bituminous composition when its mass is measured.

[0014] Thus, in the context of the invention, it has been found that the prior incorporation of an alkali hydroxide into a bituminous composition then makes it possible to permanently trap a quantity of CO2 in said bitumen composition. In the prior application WO 2018 / 206489, the applicant had proposed modifying bitumen bases by incorporating an alkali hydroxide such as NaOH and an adhesion promoter of the amine, diamine, polyamine, alkyl amido amine, amido-polyamine, imidazoline type, to lead to bituminous compositions, the capacity for resistance to aging of which is improved. Surprisingly, in the context of the invention, it has been demonstrated that the trapping of CO2, although the latter is likely to react with the alkali hydroxide present, does not lead to a significant alteration in the aging resistance properties of the bituminous compositions obtained, which was by no means obvious.

[0015] In addition, other bituminous compositions incorporating components known to be porous and gas-absorbing, such as clays (notably described in application WO 2019 / 122670), do not allow satisfactory trapping of CO2. The tests carried out presented in the examples showed that, in this case, the release of CO2, after its trapping, continued over a long period.

[0016] Thus, the invention provides both compositions which allow sufficient storage of CO2 to be of interest in the fight against the greenhouse effect and global warming and which are satisfactory, in terms of performance to meet the requirements, in particular stability to operating stresses, in the fields of road and industrial application.

[0017] According to advantageous embodiments, the bitumen base has been modified by incorporation of 0.1 to 9% by mass, preferably 0.2 to 4.5% by mass, and preferentially 0.2 to 2% by mass of alkali hydroxide, relative to the mass of bitumen base.

[0018] In general, in the compositions according to the invention, the CO2 is found, at least in part, in the bituminous composition in the form of one or more reaction product(s) with the alkali hydroxide.

[0019] In particular, the alkali hydroxide is NaOH or KOH.

[0020] Thus, when the alkali hydroxide is NaOH, at least a portion of the incorporated NaOH, or even all of the incorporated NaOH, may react with the trapped CO2 and will be found, in the bituminous composition, in the form of one or more reaction products between CO2 and NaOH, in particular in the form of NaHCO3 and Na2CO3, or exclusively in the form of NaHCO3. When the alkali hydroxide is KOH, at least a portion of the incorporated KOH, or even all of the incorporated KOH, may react with the trapped CO2 and will be found, in the bituminous composition, in the form of one or more reaction products between CO2 and KOH, in particular in the form of KHCO3 and K2CO3, or exclusively in the form of KHCO3.

[0021] According to another of its objects, the invention relates to a process for preparing a bituminous composition comprising the following successive stages: (a) obtaining a modified bitumen base, comprising the incorporation of an alkali hydroxide into a bitumen base, said incorporation being followed or accompanied by mixing, preferably under heating at a temperature in the range from 90 to 230°C, preferably in the range from 120 to 200°C, and preferentially in the range from 120 to 180°C, b) trapping CO2 in the modified bitumen base at a mass content representing, in particular, from 0.8 to 5.8% by mass, preferably from 0.5 to 4% by mass, preferentially from 0.8 to 3.5% by mass, and even more preferably from 0.8 to 2.6% by mass, or from 0.8 to 1.8% by mass of the mass of the bitumen base.

[0022] The invention also relates to a process for preparing a bituminous composition comprising the following successive steps: (a) obtaining a modified bitumen base, comprising the incorporation of an alkali hydroxide into a bitumen base, said incorporation being followed or accompanied by mixing, preferably under heating at a temperature in the range from 90 to 230°C, preferably in the range from 120 to 200°C, and preferentially in the range from 120 to 180°C, b) CO2 trapping in the modified bitumen base until CO2 saturation.

[0023] In particular, in the methods according to the invention, the incorporation of CO2 is carried out by placing the modified bitumen base in an enclosure under CO2 pressure, the enclosure being maintained at a temperature ranging from 10 to 200°C, preferably ranging from 20 to 160°C, and preferentially ranging from 25 to 160°C, or even 80 to 160°C, the CO2 pressure being chosen in particular in the range from 5.103 to 8.104 hPa, preferably in the range from 5.103 to 5.104 hPa, and preferentially in the range from 1.104 to 3.104 hPa.

[0024] Advantageously, in the processes according to the invention, in step a), the mass of alkali metal hydroxide incorporated represents from 0.1 to 9% by mass, preferably from 0.2 to 4.5%, and preferably 0.2 to 2% by mass, of the bitumen base mass.

[0025] The alkali hydroxide is preferably NaOH or KOH.

[0026] According to advantageous embodiments of the methods according to the invention, during step a), an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, is also incorporated into the bitumen base, said adhesion promoter preferably being introduced at a rate of 0.01 to 2.5% by mass, preferably 0.05 to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, of the total mass of the bitumen base.

[0027] According to particular embodiments of the processes according to the invention, during step a), one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, is (are) also incorporated into the bitumen base, said polymer(s) preferably being introduced at a rate of preferably 0.1 to 12% by mass, preferably 0.3 to 10%, and preferentially 0.5 to 7% by mass, of the mass of the bitumen base.

[0028] The methods according to the invention may comprise a step of releasing a portion of the trapped CO2 from the bituminous composition resulting from step b), at the end of which the mass of the bituminous composition is stable.

[0029] In particular, said release step leads to a quantity of CO2 trapped in the bituminous composition, corresponding to 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially 0.5 to 3% by mass, and even more preferably 0.5 to 2% or even 0.5 to 1.5% or even 0.7 to 2% by mass, relative to the mass of the bitumen base.

[0030] The invention also relates to the bituminous compositions capable of being obtained, according to the methods of the invention, and this whatever their embodiment variant.

[0031] According to another of its aspects, the invention relates to bituminous compositions comprising a bitumen base and one or more reaction products of CO2 with an alkali hydroxide, in particular chosen from NaOH and KOH.

[0032] In particular, the invention relates to bituminous compositions comprising one or more reaction products of CO2 with NaOH. In particular, such compositions comprise NaHCO3, or even NaHCO3 and Na2CO3, as reaction product(s) of CO2 with NaOH. The invention relates to bituminous compositions comprising from 2 to 210 mmol (millimoles) of NaHCO3 and Na2CO3, per 100 g of bituminous composition, preferably from 5 to 80 mmol of NaHCO3 and Na2CO3, per 100 g of bituminous composition, and even more preferably from 5 to 40 mmol of NaHCO3 and Na2CO3, per 100 g of bituminous composition. The invention also relates to bituminous compositions comprising from 2 to 210 mmol (millimoles) of Na2CO3, per 100 g of bituminous composition, preferably from 5 to 80 mmol of Na2CO3, per 100 g of bituminous composition, and even more preferably from 5 to 40 mmol of Na2CO3, per 100 g of bituminous composition.

[0033] The invention also relates to bituminous compositions comprising one or more reaction products of CO2 with KOH. In particular, such compositions comprise KHCO3, or even KHCO3 and K2CO3, as reaction product(s) of CO2 with KOH. The invention relates to bituminous compositions comprising from 2 to 145 mmol (millimoles) of KHCO3 and K2CO3, per 100 g of bituminous composition, preferably from 3 to 53 mmol of KHCO3 and K2CO3, per 100 g of bituminous composition, and even more preferably from 3 to 27 mmol of KHCO3 and K2CO3, per 100 g of bituminous composition. The invention also relates to bituminous compositions comprising from 2 to 145 mmol (millimoles) of K2CO3, per 100 g of bituminous composition, preferably from 3 to 53 mmol of K2CO3, per 100 g of bituminous composition, and even more preferably from 3 to 27 mmol of K2CO3, per 100 g of bituminous composition.

[0034] In the compositions according to the invention, whatever the embodiment variant, most often, the bitumen base represents at least 72% by mass, preferably at least 83% by mass and preferentially at least 89% by mass of the total mass of the bituminous composition.

[0035] Advantageously, a composition according to the invention, whatever the embodiment variant, further comprises an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, said adhesion promoter preferably representing 0.01 to 2.5% by mass, preferentially 0.05 to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, of the mass of the bitumen base.

[0036] According to particular embodiments, a composition according to the invention, whatever the embodiment variant, further comprises one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, preferably representing from 0.5 to 12% by mass, preferentially from 0.3 to 10% by mass, and even more preferably from 0.5 to 7% by mass, of the mass of the bitumen base.

[0037] The bituminous compositions according to the invention find different applications. Also, the invention also relates to: - the use of a bituminous composition according to the invention, for preparing a waterproofing coating, a membrane or an impregnation layer; as well as the methods for preparing such a waterproofing coating, such a membrane or such an impregnation layer; - bituminous binders comprising a bituminous composition according to the invention; - the use of a bituminous composition according to the invention, as a bituminous binder in a bituminous coating comprising a bituminous composition according to the invention, aggregates, and optionally mineral and / or synthetic fillers; as well as the processes for preparing such a bituminous coating; - the use of a bituminous composition according to the invention, as a bituminous binder in an asphalt comprising a bituminous composition according to the invention, and mineral and / or synthetic fillers; as well as the processes for preparing such an asphalt; - as well as the use of a bituminous composition according to the invention, as a bituminous binder in a surface dressing, a hot mix, a cold mix, a cold-cast mix, an emulsion gravel or a wearing course, which comprises a bituminous composition according to the invention, aggregates and / or recycled millings; as well as the processes for preparing such a surface dressing, hot mix, cold mix, cold-cast mix, such an emulsion gravel or wearing course.

[0038] According to a particular aspect, the invention relates to a process for preparing an asphalt characterized in that it comprises the hot mixing of a bituminous composition of the invention or capable of being obtained according to a process according to the invention, with mineral and / or synthetic fillers. Advantageously, the hot mixing with the bituminous composition can be carried out at a temperature of 80 to 200°C, preferably 80 to 180°C and preferentially 100 to 160°C.

[0039] The invention also relates to the use of an alkali hydroxide in a bituminous composition in which CO2 is incorporated, to obtain a stabilization of the quantity of CO2 remaining trapped within said bituminous composition. Bitumen

[0040] The invention relates to bitumen compositions modified by the addition of at least one additive or adjuvant, also called bituminous compositions. These may comprise one or more bitumens. The bitumen(s) present in the bituminous compositions according to the invention are called "bitumen base" and constitute(s) a majority content of the composition, i.e. generally represent(s) at least 72% by mass of the total mass of the bituminous composition, and preferably at least 83%, or even at least 89% and even at least 95% by mass of the total mass of the bituminous composition. Among the bitumens which 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 . particularly bitumens containing asphaltenes or pitches. Bitumens can be obtained by conventional bitumen manufacturing processes 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 to carry out vacuum distillation of atmospheric residues 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 petroleum distillation. This process makes it possible to obtain a blown, or semi-blown, or oxidized, or air-rectified or partially air-rectified bitumen. 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 performance. In conventional processes for manufacturing bituminous compositions, the operation is carried out at manufacturing temperatures of between 90°C and 230°C, preferably between 120°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.By "manufacturing temperature" is meant the heating temperature of the bitumen or bitumens before mixing with the additives, as well as the mixing temperature. The temperature and duration of heating vary according to the quantity of bitumen used and are defined by the NF EN 12594 standard. Blown bitumens can be manufactured in a blowing unit by passing a stream of air and / or oxygen through a starting bitumen or mixture of bitumens. This operation can be carried out in the presence of an oxidation catalyst, for example phosphoric acid. Generally, blowing is carried out at high temperatures, of the order of 200 to 300 °C, for relatively long durations typically between 30 minutes and 2 hours, continuously or in batches. The blowing duration and temperature are adjusted according to the targeted properties of the blown bitumen and according to the quality of the starting bitumen..

[0041] Among the bitumens that can be used according to the invention, mention may also be made of recycling bitumens.

[0042] Bitumens may be hard grade bitumens (such as grades 10 / 20 and 20 / 30) or soft grade bitumens (such as grade 160 / 220) as defined by standard EN 12591.

[0043] 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.

[0044] 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 using a standardized test NF EN 1426 at 25°C (Pene). This penetrability characteristic is expressed in tenths of a millimeter (dmm or 1 / 10 mm). Needle penetrability, measured at 25°C, according to the standardized test NF EN 1426, represents the measurement of penetration into a sample of bitumen, after a time of 5 seconds, of a needle whose weight with its support is 100 g. Alkaline hydroxide

[0045] As an example of alkali hydroxide, we can cite NaOH, KOH, Mg(OH)2, Ca(OH)2 or even Li(OH)2.

[0046] The alkali hydroxide may be introduced into the bitumen composition in the form of a suspension or a solution in a solvent (in particular water or ethanol), but is preferably directly introduced in the form of a powder or a set of particles, in particular an anhydrous alkali hydroxide. Advantageously, the alkali hydroxide, and in particular the NaOH or KOH used, forms particles whose maximum particle size is equal to or less than 100 pm, and preferably whose maximum particle size is equal to or less than 60 pm. In particular, the average maximum size of the alkali hydroxide particles, and in particular NaOH or KOH, introduced is in the range of 10 to 100 pm, preferably in the range of 20 to 60 pm. The average maximum particle size corresponds to the arithmetic mean of the maximum sizes of several particles, preferably 20 particles.Another way is to use particles of alkali hydroxide, and in particular NaOH or KOH, with at least 80% by number of said particles having a maximum size in the range of 10 to 100 pm, preferably in the range of 20 to 60 pm. The maximum size of a particle which, in general, is irregular in shape, corresponds to its largest dimension, in particular measured with a microscope, and preferably a visible light microscope. This last variant of determining the size of the particles used which is not the preferred one can be obtained on a population of 10, or preferably, 20 particles. The size of the particles introduced can be adjusted by different crushing or grinding techniques, for example by using a suitable crushing device, such as an IKA® AIL mill.

[0047] By adjusting the size of the alkali hydroxide particles introduced, as previously explained, it is possible to better control and optimally adjust the properties of the bituminous composition, in particular in terms of stability to aging.

[0048] In the context of the invention, the bituminous compositions are preferably obtained from a bitumen base and NaOH, and / or KOH, CO2, and optionally one or more components defined in the context of the invention.

[0049] In general, the alkali hydroxide introduced represents from 0.1 to 8% by mass, preferably from 0.2 to 3% by mass, and preferentially from 0.2 to 1.5% by mass, relative to the total mass of the bituminous composition.

[0050] Advantageously, the alkali hydroxide introduced represents from 0.1 to 9% by mass, preferably from 0.2 to 4.5% by mass, and preferentially from 0.2 to 2% by mass, relative to the mass of the bitumen base present in the bituminous composition. Other possible components / additives

[0051] The bituminous compositions according to the invention may also include an adhesion promoter, in particular chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof. Such adhesion promoters are in particular described in application WO 2018 / 206489 to which reference may be made for further details.

[0052] In particular, such an adhesion promoter is chosen from:

[0053] i) Amines of formula (I):

[0054] [Chem.l] R—< m in which: - R is a saturated or unsaturated, substituted or unsubstituted, optionally branched or cyclic hydrocarbon group having 8 to 24 carbon atoms. For example, R is a hydrocarbon group derived from the fatty acids of soot or the fatty acids of tall oil; and - Ri and R2, which may be the same or different, are a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms; Ri and R2 are preferably a hydrogen atom or a methyl group;

[0055] ii) The diamines and polyamines of formula (II):

[0056] [Chem.2] R—(NH—L)n—NH2(II) in which: - R is as defined for (I), - L represents a linear or branched hydrocarbon chain having 1 to 6 carbon atoms. For example, L is -(CH2)m- with m = 1, 2 or 3 and, - n is an integer greater than or equal to 1, in particular, n is equal to 1, 2, 3, 4, 5 or 6,

[0057] iii) Alkyl amido amines of formula (III):

[0058] [Chem.3] R. H RCO—N—-L—n; (neither) in which R, R2 and L are as defined for (I) and (II);

[0059] iv) The amidopolyamines of formula (IV) and the imidazolines:

[0060] [Chem.4] RCO-(NH—L>—NH2 (IV) in which R and L are as defined for (I) and (II), and p is an integer greater than or equal to 1, in particular p is an integer in the range 1 to 10.

[0061] Advantageously, the adhesion promoter is selected from amines, diamines, polyamines, alkyl amido amines and amidopolyamines comprising a fatty chain, and in particular from those previously described. In particular, the adhesion promoter is an amidopolyamine comprising a fatty chain, of formula:

[0062] [Chem.4] RCC—(NH-L)p— N Hz (IV) Or: - p is an integer greater than or equal to 1, in particular p is an integer in the range from 1 to 10, - L represents a linear or branched hydrocarbon chain comprising 1 to 6 carbon atoms, for example L is -(CH2)m- with m = 1, 2 or 3, - R is a saturated or unsaturated, substituted or unsubstituted, optionally branched or cyclic hydrocarbon group, comprising 8 to 24 carbon atoms.

[0063] Preferably, the adhesion promoter used in the bituminous compositions according to the invention is a mixture of amidopolyamines of formula (IV) in which p is an integer in the range from 1 to 10, L is -(CH2)2-, and R corresponds to the hydrocarbon chains of the fatty acids of tall oil.

[0064] In general, when present, said adhesion promoter preferably represents 0.01 to 2% by mass, preferentially 0.05% to 1% by mass, and even more preferably 0.1 to 0.3% by mass, of the total mass of the com- bituminous positions according to the invention.

[0065] Advantageously, the adhesion promoter represents 0.01 to 2.5% by mass, preferably 0.05% to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, relative to the mass of the bitumen base present in the bituminous composition.

[0066] The bituminous compositions according to the invention may also include one or more polymers. In particular, an olefinic polymer and / or an elastomer, in particular a crosslinked elastomer, may be incorporated into the bituminous compositions according to the invention.

[0067] The bituminous compositions according to the invention may, in particular, comprise one or more olefinic polymers notably chosen from: (al) random or block copolymers, preferably random, of ethylene and a monomer chosen from glycidyl acrylate and glycidyl methacrylate, comprising from 50% to 99.7% by mass, preferably from 60% to 95% by mass, more preferably 60% to 90% by mass of ethylene; (bl) random or block terpolymers, preferably random, of ethylene, of a monomer A chosen from vinyl acetate, C1 to C6 alkyl acrylates and C1 to C6 alkyl methacrylates and of a monomer B chosen from glycidyl acrylate and glycidyl methacrylate; in particular said terpolymers comprising from 0.5% to 40% by mass, preferably from 5 to 35% by mass, more preferably from 10% to 30% by mass of units derived from monomer A and from 0.5% to 15% by mass, preferably from 2.5% to 15% by mass of units derived from monomer B, the remainder being formed from units derived from ethylene; (cl) copolymers resulting from the grafting of a monomer B chosen from glycidyl acrylate and glycidyl methacrylate, onto a polymeric substrate; in particular the polymeric substrate is chosen from polyethylenes, in particular low-density polyethylenes, polypropylenes, random or block copolymers, preferably random, of ethylene and vinyl acetate and random or block copolymers, preferably random, of ethylene and C1 to C6 alkyl acrylate or C1 to C6 alkyl methacrylate, comprising from 40% to 99.7% by mass, preferably from 50% to 99% by mass of ethylene; preferably said grafted copolymers comprising from 0.5% to 15% by mass, preferably from 2.5% to 15% by mass of grafted units derived from monomer B.

[0068] The bituminous compositions according to the invention may, in particular, comprise one or more elastomers, in particular chosen from crosslinked elastomers. Such elastomers known to be incorporated into a bituminous composition are, in particular, the copolymers SB (block copolymer of styrene and butadiene), SBS (block copolymer styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SBS* (styrene-butadiene-styrene star block copolymer), SBR (styrene-b-butadiene-rubber), EPDM (ethylene propylene diene modified).

[0069] According to certain particular embodiments, a bituminous composition according to the invention comprises from 0.05% to 10% by mass, preferably from 0.1% to 8% by mass and preferentially from 0.3 to 6% by mass, of olefinic polymer(s) and / or elastomer(s), relative to the total mass of said bituminous composition.

[0070] Advantageously, the mass of olefinic polymer(s) and / or elastomer(s) represents from 0.1 to 12% by mass, preferably from 0.3 to 10%, and preferentially from 0.5 to 7% by mass, relative to the mass of the bitumen base present in the bituminous composition.

[0071] Bituminous compositions, also called bituminous compositions according to the invention

[0072] Although it is not excluded that the bituminous compositions according to the invention comprise one or more other additives, in particular chosen from those conventionally used in bituminous compositions, preferably, the bitumen base, the CO 2, the alkali hydroxide, or even the adhesion promoter and / or the elastomer and / or the olefinic polymer represent at least 90% by mass, preferably at least 95% by mass, or even 100% by mass of the total mass of the bituminous composition.

[0073] The different components of the bituminous composition are dispersed in the bituminous composition, and therefore in the bitumen base.

[0074] Examples of particularly preferred bituminous compositions are given below.

[0075] In particular, the invention relates to bituminous compositions comprising a bitumen base modified by incorporation of an alkali hydroxide and in which CO2 has been incorporated and remains trapped, optionally in a form having chemically reacted with another component present in the composition.

[0076] In particular, such bituminous compositions comprise a bitumen base, modified by incorporation of: - 0.1 to 9% by mass, preferably 0.2 to 4.5% by mass, and preferentially 0.2 to 2% by mass relative to the mass of bitumen base, of alkali hydroxide, and in particular of NaOH or KOH or one of their mixtures, - an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, in an amount of 0.01 to 2.5% by mass, preferably 0.05 to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, of the mass of the bitumen base, - optionally, one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, at a rate of 0.5 to 12% by mass, preferably 0.3 to 10% by mass, and even more preferred from 0.5 to 7% by mass, of the mass of the bitumen base, - CO2 which remains trapped in said composition, possibly in a form having chemically reacted with another component present in said bituminous composition, and which represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, relative to the mass of the bitumen base.

[0077] The compositions below are particularly preferred: 1) bituminous compositions, which comprise a bitumen base, modified by incorporation of: - 0.1 to 9% by mass relative to the mass of bitumen base, of alkali hydroxide, and in particular of NaOH or KOH or one of their mixtures, - an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, at a rate of 0.01 to 2.5% by mass relative to the mass of the bitumen base, - optionally, one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, at a rate of 0.5 to 12% by mass relative to the mass of the bitumen base, - CO2 which remains trapped in said composition, possibly in a form having chemically reacted with another component present in said bituminous composition, and which represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, relative to the mass of the bitumen base; 2) bituminous compositions, which comprise a bitumen base, modified by incorporation of: - from 0.2 to 4.5% by mass relative to the mass of bitumen base, of alkali hydroxide, and in particular of NaOH or KOH or one of their mixtures, - an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, at a rate of 0.05 to 1.1% by mass, relative to the mass of the bitumen base, - optionally, one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, at a rate of 0.3 to 10% by mass, relative to the mass of the bitumen base, - CO2 which remains trapped in said composition, possibly in a form having chemically reacted with another component present in said bituminous composition, and which represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass relative to the mass of the bitumen base; 3) bituminous compositions, which comprise a bitumen base, modified by incorporation of: - 0.2 to 2% by mass relative to the mass of bitumen base, of alkali hydroxide, and in particular of NaOH or KOH or one of their mixtures, - an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, at a rate of 0.1 to 0.4% by mass, relative to the mass of the bitumen base, - optionally, one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, at a rate of 0.5 to 7% by mass, relative to the mass of the bitumen base, - CO2 which remains trapped in said composition, possibly in a form having chemically reacted with another component present in said bituminous composition, and which represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, relative to the mass of the bitumen base.

[0078] In such compositions, preferably, the adhesion promoter(s), or even the polymer(s) present, are chosen from those specifically described in the context of the present description.

[0079] It is possible for the trapped CO2 to react with the alkali hydroxide introduced into the composition. When the alkali hydroxide is NaOH, the latter may be found, within the bituminous composition, totally or partially in the form of one or more reaction products with the trapped CO2, in particular in the form of a mixture of NaHCO3 and Na2CO3, or even exclusively in the form of NaHCO3. When the alkali hydroxide is KOH, the latter may be found, within the bituminous composition, totally or partially in the form of one or more reaction products with the trapped CO2, in particular in the form of a mixture of KHCO3 and K2CO3, or even exclusively in the form of KHCO3.

[0080] It is possible for such compositions to comprise one or more other additives. However, it is preferable for the above-mentioned components and the bitumen base to constitute the bulk of the bituminous composition. Advantageously, in such compositions, the bitumen base represents at least 72% by mass of the total mass of the bituminous composition, and preferably at least 83%, or even at least 89% and even at least 95% by mass of the total mass of the bituminous composition. This % will depend on the presence or absence of additional polymers, in particular. According to particular embodiments of the above-mentioned compositions- data, the bitumen base may be modified only by the incorporation of the listed components.

[0081] Of course, advantageously, these bituminous compositions will have a mass which remains stable at 25°C and under 1013.25 hPa, over a period Ps of at least 10 hours, preferably at least 15 hours. This stability criterion is as previously defined in the context of the present description.

[0082] Preparation of the bituminous compositions according to the invention and preparation process according to the invention

[0083] 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 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 previously heated. According to a particular embodiment of the invention, a bitumen composition is prepared by bringing into contact: - the bitumen base; - the desired mass of alkali hydroxide; - possibly one or more other additive(s).

[0084] Conventionally, the mixture of the bitumen base and the alkali hydroxide, or even the other additive(s) present, is carried out at temperatures ranging from 90 to 230°C, preferably from 120 to 200°C, and preferentially from 120 to 180°C.

[0085] Such a mixture is carried out with stirring, in particular, for a period of 5 minutes to 10 hours, preferably 10 minutes to 3 hours, preferentially 10 to 90 minutes, and even more preferably 20 to 90 minutes. The mixture can be carried out by means of stirring producing high shear or stirring producing low shear. In particular, the mixture is carried out with stirring of 100 to 1000 rpm (rotations per minute), preferably 100 to 600 rpm, and preferentially 150 to 500 rpm. Stirring is carried out so as to facilitate the dispersion and good distribution of the alkali hydroxide in the bitumen base. A person skilled in the art will adjust the time and power of the stirring to obtain a satisfactory distribution.

[0086] When an adhesion promoter and / or one or more polymers are incorporated into the bitumen base, it (they) is (are) preferably introduced after the alkali hydroxide.

[0087] The incorporation of CO2 into the composition leading to its trapping in the bitumen base is carried out, after the incorporation of the alkali hydroxide, and if one or more other components are incorporated, preferably after this incorporation also. Such trapping can be achieved by placing the bitumen base modified by incorporation of the alkali hydroxide, or even one or more other additives, in a CO2 pressure chamber, the chamber being maintained at a temperature, generally ranging from 10 to 200°C, preferably ranging from 20 to 160°C, in particular from 25 to 160°C. The CO2 pressure will be chosen in particular in the range from 5.103 to 8.104 hPa (Hectopascal, corresponding to 5-80 bars), preferably in the range from 5.103 to 5.104 hPa, and preferentially in the range from 1.104 to 3.104 hPa. Maintenance under these conditions in the pressure chamber will be ensured for a duration, most often from 5 minutes to 100 hours. This duration will be adapted, by the person skilled in the art, depending in particular on the temperature chosen when incorporating the CO2, the CO2 pressure used and the quantity of CO2 desired.For example, the incorporation of CO2 will be carried out over a period of 5h to 50h, when a temperature of 80 to 160°C is used, and over a period of 30 minutes to 5 hours when a temperature of 10 to 40°C is used, for an identical pressure. The CO2 incorporation step can be carried out in the presence or absence of mechanical agitation. If such agitation is present, the agitation speed can, for example, vary between 200 rpm and 6000 rpm.

[0088] The incorporation of CO2 is favored at the lowest temperatures. The person skilled in the art will be able to play on the 3 variables T°C / Pressure and duration of exposure of the composition to a CO2 pressure, to obtain an optimal incorporation of CO2 within the composition, and in particular to obtain a saturation of the composition in CO2.

[0089] In general, at the end of the CO2 trapping step, the trapped CO2 represents from 0.8 to 5.8% by mass, preferably from 0.5 to 4% by mass, preferentially from 0.8 to 3.5% by mass, and even more preferably from 0.8 to 2.6% by mass, or even from 0.8 to 1.8% by mass, of the mass of the bitumen base.

[0090] After such a CO2 trapping step, a step of releasing a portion of the trapped CO2 generally occurs. This release step or phase Pr is generally at least 3 hours, or even at least 5 hours, most often 5 to 10 hours, and typically 5 hours, after the end of the CO2 trapping step. The end of the CO2 trapping step corresponds, in particular, to the moment when the bituminous composition is no longer under CO2 pressure. This release can occur naturally when the bituminous composition is stored at 25°C and at 1013.25 hPa. Such a release phase under these conditions typically lasts at least 5 hours, and in particular 5 to 10 hours. It is also possible that the bituminous composition is subjected to heating during this Pr release phase, which will have the effect of accelerating the release of part of the CO2 and therefore reducing the duration of the release phase.During such a release phase, generally 0.1 to 0.7%. mass of the initially incorporated CO2, and in particular from 0.1 to 0.7% by mass of the initially incorporated CO2, can be released, and leads to a mass % of CO2 relative to the mass of the bitumen base, which still remains at least equal to 0.5%, and typically in the range of 0.5 to 5%, 0.5 to 4%, 0.5 to 3%, 0.5 to 2% or 0.5 to 1.5% or 0.7 to 2%. Once the release phase Pr is complete, the remaining CO2 remains trapped within the bituminous composition, under so-called standard storage conditions (at 25°C and under 1013.25 hPa), which results in a stabilization of the mass of the bituminous composition. The mass of the bituminous composition is understood as the mass of all the components present (in particular the bitumen base, the alkali hydroxide introduced, and any other components possibly present) but also of the CO2 trapped in the bituminous composition when its mass is measured.

[0091] It is possible that some of the CO2 trapped during the trapping step has reacted with the alkali hydroxide. The so-called trapped CO2 may therefore be in the form of CO2 and reaction product(s) with the alkali hydroxide, such as NaHCO3 and Na2CO3 when the alkali hydroxide is NaOH or such as KHCO3 and K2CO3 when the alkali hydroxide is KOH. Thus, the CO2 which is eliminated during this release phase Pr may be all or part of the CO2 trapped in the composition, still in the CO2 form.

[0092] The invention also relates to the bituminous compositions capable of being obtained by the process described in the context of the invention, and in particular the bituminous compositions, which can be described as stabilized, which are capable of being obtained at the end of the step of releasing part of the trapped CO2.

[0093] 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 achieve the quantities given for the description of the bituminous compositions according to the invention.

[0094] Use and implementation of the bituminous compositions according to the invention

[0095] Various uses of the bituminous compositions obtained according to the invention are envisaged. In particular, the bitumen compositions according to the invention can be used as a bituminous binder. 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 bodies and their surfacing, as well as for carrying out all road works.

[0096] By bituminous coating, we mean a mixture of a bituminous binder with aggregates and possibly mineral and / or synthetic fillers. The bituminous mix comprises a bituminous binder as described in the context of the invention, and possibly mineral and / or synthetic fillers, preferably chosen from fines, sand, gravel and recycled millings. The aggregates are mineral and / or synthetic aggregates, in particular recycled millings, with dimensions greater than 2 mm, preferably between 2 mm and 20 mm.

[0097] Also, 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.

[0098] 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.

[0099] 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 pavements, whereas asphalts have a compaction of less than 100% and are used to manufacture roads. Unlike asphalts, asphalts are not compacted with a roller during their installation.

[0100] Also, 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.

[0101] Another aspect of the invention relates to the use of a bitumen composition in various industrial applications, in particular for preparing a waterproofing coating, a membrane or an impregnation layer. As regards industrial applications of the bituminous compositions, mention may be made of the manufacture of waterproofing membranes, noise-reducing membranes, insulation membranes, surface coverings, carpet tiles, impregnation layers.

[0102] Due to the incorporation of CO2, the compositions according to the invention have a lower viscosity than conventional bituminous compositions. It is thus possible to implement them using lower temperatures. Thus, the invention also relates to methods for preparing a coating comprising the hot mixture, at a temperature of 80 to 200°C, preferably 80 to 180°C and preferentially 100 to 160°C, of ​​a bituminous composition according to the invention or capable of being obtained according to a process according to the invention, with aggregates and / or recycled millings, and optionally mineral and / or synthetic fillers.

[0103] The invention also relates to a process for preparing an asphalt comprising hot mixing, at a temperature of 80 to 200°C, preferably 80 to 180°C and preferentially 100 to 160°C, of ​​a bituminous composition according to the invention or capable of being obtained according to a process according to the invention, with mineral and / or synthetic fillers.

[0104] The invention also relates to the use of an alkali hydroxide in a bituminous composition in which CO2 is incorporated, to obtain a stabilization of the quantity of CO2 remaining trapped within said bituminous composition.

[0105] The characteristics described in connection with the bituminous composition and / or the method for preparing a composition according to the invention apply to the uses, products and methods described in this section. Also, to obtain the stabilization of the quantity of CO2 remaining trapped within said bituminous composition, the components and quantities as previously defined, and / or the conditions of incorporation and / or storage will, advantageously, be applied.

[0106] The examples below, with reference to the appended Figures, illustrate the invention, but are not limiting in nature. Brief description of the drawings

[0107] [Fig.l] [Fig.l] represents the evolution of the % of CO2 remaining in the sample (% by mass compared to the mass of the total composition at time t) as a function of the time elapsed after leaving the PAV (h), for compositions F3-1, F3-2, F3-3 and pure bitumen.

[0108] [Fig.2] [Fig.2] represents the evolution of the mass of the bituminous compositions (g) as a function of the time elapsed after leaving the PAV (h), for the compositions F3-1, F3-2, F3-3 and pure bitumen.

[0109] [Fig.3] [Fig.3] represents the evolution of the Phase Angle (°) as a function of the Complex Shear Modulus (Pa), for compositions F3-1 after incorporation of CO2 and F3-1 as is.

[0110] [Fig.4] [Fig.4] represents the evolution of the Phase Angle (°) as a function of the Complex Shear Modulus (Pa), for compositions F3-1 after incorporation of CO2 and F3-1 after aging for 25 hours (v25h).

[0111] [Fig.5] [Fig.5] represents the evolution of the remaining CO2 (mass % relative to the bitumen base mass) as a function of the time elapsed after leaving the PAV (h), for the compositions pure bitumen, F3-1, Dellite, Sepiolite, F3-2, F3-3 and F8, after incorporation of CO2.

[0112] [Fig.6] [Fig.6] represents the solid sodium NMR spectra of a bituminous composition according to the invention at a given time t0, then at t0+8 months of storage at room temperature (25°C), as well as the reference spectrum of NaHCO3. Examples Part 1. Examples of implementation

[0113] Pure bitumen type 35 / 50 according to standard EN 12591 from the Feyzin refinery, using a conventional direct refining process, was modified by incorporating one or more additives, then trapping CO2. In the case of composition F 3-1 presented in the examples below, another bitumen also 35 / 50 (from the Brunsbüttel refinery) was used.

[0114] The adhesion promoter H1 was an amine additive: WETFIX BE from Akzo Nobel Surface Chemistry AB (CAS 68910-93-0).

[0115] Sodium hydroxide was supplied in the form of anhydrous pellets (CARL ROTH GMBH & Co. KG, Item No. 9356.1) and its purity was greater than 99%. The sodium hydroxide pellets were ground to a fine powder using an IKA® Ail mill (IKA-Werke GmbH & Co) at 28000 rpm for about 30 seconds, resulting in sodium hydroxide (NaOH) particles. Their average maximum size measured on 20 particles using a microscope was about 50 μm.

[0116] The results presented were obtained under the following conditions: - soda was introduced into the bitumen base already heated to 160°C; - Mixing temperature: 160°C; - Stirring speed: 400 rpm; - Stir for 3 hours.

[0117] The adhesion promoter was then introduced at a rate of 0.2% by mass, relative to the mass of bitumen + NaOH + adhesion promoter. Incorporation of CO2 into bitumen

[0118] To incorporate CO2 into the bituminous compositions, a PAV device (model of the device used: PAV3 from the company ATS [Applied Test Systems]) was used. This device is usually used to induce oxidation of bitumen, according to standard NF EN 14769. It simulates the long-term oxidative aging of a bitumen composition, representing oxidation over several years on the road. This test is usually carried out at a temperature of 100°C, at a pressure of 21 bar and for 20 hours using a compressed air cylinder. The bitumen is introduced into the device in cups (10) each containing 50 g of bitumen composition. bitumen.

[0119] In the context of the invention where an incorporation of CO2 into a bituminous composition is desired, instead of using a compressed air cylinder as for the aging tests, a pure CO2 cylinder (99%) was used and connected to the PAV device. The bitumen base, incorporating or not the selected additive(s), was placed for 20 hours, at a temperature of 25°C (unless otherwise specified in the examples below), under a pressure of 21.103 hPa (21 bar) of CO2, so as to incorporate the CO2 into the bitumen composition. At the end of these 20 hours, the device was immediately returned to atmospheric pressure and the cups were immediately removed. Measurement of CO2 content in bitumen

[0120] The incorporated CO2 content was measured by weighing, with a precision balance (Balance Sartorius Practum 224-1S), the cups containing the bitumen before and after incorporation of CO2 by PAV (from the English "Pressure Ageing Vessel"), as detailed below, were weighed. The measurements are carried out at 25 °C and under atmospheric pressure (1013.25 hPa). After PAV in air, there is no difference before and after the PAV. After PAV in CO2, the difference in mass obtained therefore corresponds to the mass of CO2 incorporated in the bitumen. CO2 trapping stability study

[0121] The stability of CO2 trapping was evaluated at the end of these 20 hours of PAV, maintaining the bituminous composition obtained at room temperature (25°C) and under atmospheric pressure (1013.25 hPa). The results obtained are presented in Table 1 below and in [Fig.l]. The times of 5h, 24h and 168h correspond to the time elapsed, after the end of the CO2 incorporation step, and therefore start as soon as the bituminous compositions studied leave the PAV device used for the incorporation of CO2.

[0122] In Table 1, the % NaOH and % CO2 are % by mass of the quantity incorporated, given relative to the mass of the bitumen base used. The % CO2 is obtained by weighing the samples, before and after the trapping step under PAV, then over time. The relative % CO2 is the % of CO2 still incorporated at a given time, relative to the % CO2 incorporated at the PAV outlet. % variation tO for the mass of the composition is the % variation obtained by comparing the mass of the composition at a given time and that at the PAV outlet. % variation 5h for the mass of the composition is the % variation obtained by comparing the mass of the composition at a given time and that obtained after 5h at 25°C after leaving the PAV.

[0123] All compositions presented in Table 1 were prepared with incorporation of the adhesion promoter, at a rate of 0.2% by mass, relative to the mass bitumen + NaOH + adhesion promoter, which also corresponds to 0.2% by mass relative to the mass of bitumen alone.

[0124] In Table 1, the “% NaOH added” and the “% CO2 incorporated at the PAV outlet” and the % of CO2 are given in % by mass relative to the mass of the bitumen base (more simply called pure bitumen in the table) or relative to the total mass of the bituminous composition (at the time indicated) therefore including bitumen+NaOH+WETIX BE+CO2 (more simply called composition or compo in the table). In the case of NaOH (just as in the case of the WETIX BE adhesive dope), if these % given with two figures after the decimal point are the same, only one value appears in the Table. In Table 1, when the second figure after the decimal point, or even the last two figures after the decimal point, is (are) 0, it (they) is (are) not mentioned.

[0125] The relative % CO2 is the % of CO2 remaining compared to the % of CO2 incorporated at the PAV outlet. % NaOH added CO2 incorporation conditions at 21bar %CO2 incorporated ■in PAV sorbate Mass composition at PAV outlet (g) (*) Time at 25°C after PAV outlet Temp (°C) Time (h) After 5h After 24h After 96h % reiatff CO2 % CO2 Mass (g) composition % variation to % relative CO2 % CO2 Mass (g) composition % variation tQ % variation 5h % reiatif CO2 % CO2 Mass composition % variation to % variation 5h 0 pure bitumen (without NaOH addition) 25 20 l,03%m base pure bitumen 1,02% m compo 50,8461 (=50,3259 40,5202) 61% 0,63%m pure bitumen 0,63%m compo at 5h 50,6429 0.40% 36% 0.37%m pure bitumen 0.37% m compo at 24h 50.5121 0.66% var to 0.26% var 5h 12% 0.13% m pure bitumen 0.13% m compo at 96h 50.3892 0.90% var tO 0.50% var 5h 0.5 % m compo (0.5%m pure bitumen) F 3-1 25 20 1.1 l%m base pure bitumen 1.09% m compo 50.8983 (=50.3411 +0.5572) 57% 0.63%m pure bitumen 0.62%m compo at 5h 50.6575 0.47% 53% 0.59%m pure bitumen 0.58% m compo at 24h 50.6347 0.52% var to 0.04% var 5h 51% 0.57% m pure bitumen 0,56% m compo at 96h 50.6243 0.54% var tO 0.06% var 5h 1% m compo (1.01% m pure bitumen) F 3-2 25 l,16%m pure bitumen base 1.13% m compo 50.5988 (=50.0266 +0.5722) 77% 0.89%m pure bitumen 0.83%m compo at 5h 50.4688 0.26% 76% 0.88%m pure bitumen 0.86%m compo at 24h 50.4518 0.27% var tO <0.01% var 5h 75% 0.87% m pure bitumen 0.85% m compo at 96h 50.4575 0.28% var tO 0.02% var 5h 1.5% m compo (1.53% m pure bitumen) F 3-3 25 20 l.45%m pure bitumen base 1.41% m compo 51.0707 (=50.3495 +0.7212) 89% l.29%m pure bitumen l.26%m compo at 5h 50.9899 0.16% 88% l.29%m pure bitumen 1.25% m compo at 24h 50.9876 0.16% var tO <0.01% var 5h i / / , 0126] [Tables 1]

[0127] “ / ” not measured.

[0128] (*) in parentheses is mentioned the mass of the composition before incorporation CO2, then the mass of incorporated CO2 which is calculated by taking the difference with the mass of the composition measured at the PAV outlet.

[0129] [Fig.l] and [Fig.2] clearly demonstrate a stabilization of the mass of the bituminous compositions according to the invention, after a short period of CO2 release (at most during the first 5 hours following the end of the PAV cycle implemented for CO2 trapping). In the absence of soda, the release of CO2 continues over a much longer period. After 24 hours at 25°C, the bitumen base not modified by the addition of soda only contains a quantity of CO2 which represents 0.36% of the mass of CO2 initially incorporated (% relative), whereas in the case of the compositions according to the invention, the latter is always greater than 0.5%. Furthermore, for the bituminous composition F 3-1, a weighing was also carried out after a storage period of 168 hours at 25°C after removal from the PAV.The relative % of CO2 (i.e. the % of CO2 remaining compared to the % of CO2 incorporated at the outlet of the PAV) was still 51%, which clearly shows the stabilization of the composition and retention of CO2, after a first rapid release stage lasting only a few hours.

[0130] Furthermore, the release of CO2 is materialized by a change in the appearance of the bituminous composition, the surface of which presents roughness and reliefs due to the degassing of CO2.

[0131] From the refinery to its application, the bitumen can be handled and stored hot, around 160°C. Therefore, hot desorption was also investigated, for composition F 3-1. For this, after approximately 100 hours of storage at 25°C, after the end of the CO2 trapping step (the mass of the bituminous composition was therefore stabilized), a sample of it was placed in a microchamber, for 1 hour at 160°C. The quantity of CO2 released during the experiment was measured and corresponded to only approximately 10% of the mass of CO2 trapped, before this heating phase.

[0132] It has also been demonstrated that in the bituminous compositions according to the invention, at least part of the trapped CO2 had reacted with the introduced alkali hydroxide, and was therefore in the form of one or more CO2 / alkali hydroxide reaction products. [Fig.6] represents the solid sodium NMR spectra of the composition F 3-3 according to the invention at a given time t0 located after the release phase for 24 hours, then at t0+8 months of storage at room temperature (25°C), as well as the reference spectrum of NaHCO3. The spectra are obtained by Nuclear Magnetic Resonance of the 23Na nucleus on a 300 MHz spectrometer, on solid samples rotated at the magic angle at a frequency of 8 kHz, by pulse direct with heteronuclear decoupling of 'H' nuclei. 256 scans were acquired for each spectrum.

[0133] The spectrum obtained highlights the presence of an intense peak which corresponds to NaHCO3. There are no other visible peaks, and in particular there is an absence of a peak which would correspond to NaOH. Evaluation of bituminous compositions

[0134] The bituminous compositions were evaluated, while their mass had stabilized at 25°C. The following evaluations were carried out by: - measurement of needle penetrability at 25°C (abbreviation: Pene), according to standard EN 1426, the results being expressed in 1 / 10 mm, - measurement of the ring-ball softening temperature (abbreviation: TBA), according to standard EN 1427, the results being expressed in °C, - to assess the aging resistance, such measurements were also carried out, after accelerated long-term aging in a Pressure Ageing Vessel (PAV), operating at 100°C and 21MPa air pressure. The aging time used was 25 hours. The results are shown in Table 2 below. - rheological characterizations were carried out using a dynamic shear rheometer from Malvem, Kinexus brand, Lab + model. The tests were carried out using 20 mm plane / plane geometers. The results were obtained by performing frequency sweeps in the linear domain at 70°C. Two types of characterizations were carried out: determination of the complex shear modulus (in Pa) by varying the angular frequency i) with a temperature sweep from 30 to 70°C ([Fig.3]); ii) with a frequency sweep from 0.1 rad / s to 100 rad / s ([Fig.4]).

[0135] [Tables2] Bitumen base As is After aging PAV (2) Penetrability at 25°C (1 / 10mm) 41 18 TBA ("C) 54.6 70 4TBA) ("O 15.4 F3-1 without CO2 After aging PAV (2) With CO2(1) With CO2(1) After aging PAV (2) Penetrability at 25°C (1 / 10mm) 41 33 52 35 TBA CO 58 66.4 53.2 63.4 Z <TBA) CO 8,4 10,2

[0136] (1) CO2 incorporation (20h-25°C-21 bars)

[0137] (2) PAV aging (25h-100°C-21 bars)

[0138] These results show that the trapping of CO2 within the bituminous composition leads to both an increase in penetrability and a decrease in TBA. Furthermore, in the case of the compositions according to the invention, it appears that the variation in penetrability and TBA, after PAV aging, remains greatly reduced, compared to what is observed for the bitumen base alone. Thus, the benefit of using the alkali hydroxide and the adhesion promoter is maintained: the composition has better resistance to aging than the bitumen base.

[0139] The analyses presented in [Fig.3] and [Fig.4], for their part, highlight that the introduction of CO2 makes it possible to lower the viscosity of the bituminous composition. Thus, the compositions according to the invention will be able to be implemented at lower temperatures than those conventionally used, for example for the preparation of hot mixes. Furthermore, the trapping of CO2 does not alter the oxidation resistance properties of the bituminous compositions obtained within the framework of the invention. Modulations of CO2 incorporation conditions

[0140] Other tests were carried out by modifying the duration and / or the temperature of the CO2 trapping step in the PAV enclosure under 21 bars.

[0141] The results presented in Table 3 were obtained. They highlight that the quantity of CO2 initially trapped can be modulated by the choice of parameters used during the trapping stage.

[0142] In Table 3, the % NaOH and % CO2 are % by mass of the quantity incorporated, given relative to the mass of the bitumen base used. The % of CO2 is obtained by weighing the samples, before and after the trapping step under PAV, then over time. The relative % of CO2 is the % of CO2 always incorporated at a given time, relative to the % of CO2 incorporated at the exit of PAV. % variation tO for the mass of the composition is the % of variation obtained by comparing the mass of the composition at a given time and that at the exit of the PAV. % variation 5h for the mass of the composition is the % of variation obtained by comparing the mass of the composition at a given time and that obtained after 5h at 25°C after exiting the PAV.

[0143] All the compositions presented in Table 3 were prepared with incorporation of the adhesion promoter, at a rate of 0.2% by mass, relative to the bitumen mass.

[0144] It appears that the bituminous compositions for which the incorporation of CO2 is carried out at 25°C have a greater quantity of incorporated CO2, and that, in addition, the incorporation is more stable over time. It also appears that the incorporation of CO2 increases with the quantity of soda incorporated in the bituminous composition. % NaOH added CO2 incorporation conditions at 21 bar %CO2 incorporated at the PAV outlet Mass composition at the PAV outlet 0(9} Time at 25 C after the PAV outlet Temp fC) Time (h) After 5h (or 4h if specified) After 24ii After 96h % relative CO 2 % CO2 Mass (g) composition % variation to % relative CO2 % CO2 Mass (g) composition % variation to % variation 5h % relative CO2 % CO2 Mass (g) composition % variation to % variation 5h 0 25 72 1.44 %m pure bitumen 1.42%m compo at tO 50.7592 (=50.04 +0.7192) 0.9% 0.1 %m pure bitumen 0.1 %m campa at to 50.0465 1.40% / / / rfi 0.5 25 72 0.30%m pure bitumen 0.88%m compc at tO 50.3516 (=49.3071 +0.4445) 64% 0.58%m pure bitumen 0.57%m campa at 5h 50.1931 0.31% 59% 0.53%m pure bitumen 0.53%m compo at 24h 50.1713 0.36% var to 0.04% var 5h 53% 0.48%m pure bitumen 0.47%m compo at 96b 50.1445 0.41 % var to 0.1% var 5h 1 25 72 1.28%m pure bitumen 1.25%m compo at tO 50.6311 (=50+ 0.6311) 84% 1.07%m pure bitumen 1.05%m campa at 5h 50.5286 0.20% 82% 1.05%m pure bitumen 1.03%m compo at 24h 50.5206 0 22% var to 0.02% var 5h / 7 1.5 25 72 1.67%m pure bitumen 1.61%m compo at tO 50.8186 (=50+ 08186) 92% 1.54%m pure bitumen 1.5%m campa at 5h 50.7564 0.14% 92% 1.53%m pure bitumen 1.48%m compo at 24h 50.7498 0.14% var to 0.01% var 5h / V . [Tables 3] % NaOH added CO2 incorporation conditions at 21 bar %CO2 incorporated at the outlet of the PAV Mass composition at the outlet of this PAV fj (9) Duration at 2°C after the outlet of the PAV Temp C'Q Duration (b) After 5h (or 4h if specified) After 24h After 96h % relative CO2 % CO2 Mass (g) composition % variation :0 % relative CO2 % CO2 Mass (g) composition % variation tO % variation 5h 0 / / 9 reiat if CO2 % CO2 Mass (g) composition % variation to % variation 5h 8 25 20 1.03%m pure bitumen 1.02%m compo at tO 50.8461 (=50.3259 +0^6202^ 61% 0.63%m pure bitumen 0.63%m compo at 5h 50.6429 0.40% 36% 0.37%m pure bitumen 0.37% m compound at 24h 50.5121 Q .66% vartO 0.26% var5h 12.% 0.13%m pure bitumen 0.13%m compound at 96h 50.3892 0.9% var tO 0.5% var 5h 0.5 25 20 1.11%m pure bitumen 1.09%m ccmoo at tO 50.8983 ¢=50.3411 +0.5572) 57% 0.63%m pure bitumen 0.62%m ccmoo at 5h 50.6575 0.47% 53% 0.59%m pure bitumen 0.58% m compo at 24h 50.6347 0.52% vartO 0.05% var 5h 51% 0.57%m pure bitumen 0.56%m compo at 96 b 50.6243 0.54% var to 0.07% var 5h T 25 20 1.14%m pure bitumen 1.13%m compo at tO 50.5988 (=50.0266 +0.5722) 77% 0:89%m pure bitumen 0.88%m compo at 5h 50.4688 0.28% 76% 0.88%m pure bitumen 0.86%m compo at 24h 50.4518 0.27% var tO 0.01% var 5h 75% 0.87%m pure bitumen 0.85%m compo at 96h 50.4575 0.28% var to 0.02% var 5h 1.5 25 20 1.43%m pure bitumen 1.41%m compo at tO 51.0707 (=50.3495 +0.7212) 89% 1.29%m pure bitumen 1.26%m compo at 5h 50.9899 0.16% 38% 1.29%m pure bitumen 1.25% m compo at 24h 50.9876 0.16% var tO <0.01% var 5b vy / 0 25 1 0.2%m pure bitumen Q,2%m compo at 10 50.2081 (=50.1066 +0.1015) 48% (4h) 0.1%m pure bitumen 0.1%m compound at 4h 4b,: 50.1551 0.11% vartO 25% 0.05%m pure bitumen 0.05%m compound at 24h 50.1316 0.15% varTO 0.05% var 4h / / / . [Table 3] continued % NaOH added CO2 incorporation conditions at 21 bar %CO2 incorporated at the PAV outlet Mass composition at the PAV outlet C) ts) Time at 25°C after the PAV outlet Temp (“Cj Time (h) After 5b {or 44 if specified) After 24h After 96h % relative CO2 % CO2 Mass (g) composition % variation to oz 70 relative CO2 % CO2 Mass (g) composition % variation 10 % variation 5h % relative CO2 c <yz Masse ig) composition % variation tO % varieton 5 h 0,5 25 1 0,2%m bitume pur 0,2%m compo à fô 49,9457 (=49,8458 +0,1001} 71% (4h) 0,143% bitume pur 0,142%m compo à 4h 4h : 49,9166 0,06% ver to 72% 0,146% m bitume pur 0.145% m compo à 24h 49,918 0,06% var to <0.01 %var 4h / ! 25 1 0,31%m bitume pur 0 3%m compc à tO 50,2638 (= 50.1108 +0,153) 93% (4hj 0.29%m bitume pur 0,28%m compo à 4h 4h : 50,2524 0,02% ver to 90% 0.2:8%m bitume pur 0,27%m compo à 24h 50,2489 0,03% var to <0.01 %var 4h / / ! 1,5 25 1 0 39%m bitume pur 0,38%m compo à tO 53,3303 (-53,1281 +0.2022} 92% (4h) 0.36%m pure bitumen 0.35%m compound at 4h 4h: 53.3148 0.03% ver to 90% 0.35%m pure bitumen 0.34%m compound at 24h 53.3092 0.04% var to 0.01% var 4h / . / f 0.5 120 20 0.B9%m pure bitumen 0.68% compc at tC 50.6101 (=50.2742 +0.3449} 73 (4h) 0.5%m pure bitumen 0.5%m compo at 4h 4h: 50.5248 0.19% var to 64% 0.44%m pure bitumen 0.44%m compo at 24h 50,494 0.25% var to 0.06% var 4h s A >' . [Table 3] continued

[0148] “ / ” not measured.

[0149] (*) in parentheses is mentioned the mass of the composition before incorporation CO2, then the mass of incorporated CO2 which is calculated by taking the difference with the mass of the composition measured at the PAV outlet. Comparative tests

[0150] For comparison, other bituminous compositions modified with an additive other than an alkali hydroxide were subjected to the same CO2 trapping step. The results presented were obtained under the following conditions: - The selected additive was introduced into the bitumen base already heated to 160°C; - Mixing temperature: 160°C; - Stirring speed: 200 rpm; - Stirring for 30 minutes; - The amount of additive was 3.0% m / m relative to the total mass of the bituminous composition obtained, corresponding to 3.1% m / m relative to the mass of the bitumen base.

[0151] The results obtained on the bituminous compositions 24 hours after the CO2 trapping step under PAV are presented in Table 4 and [Fig.5]. They show that none of the other additives leads to a stabilized trapping of part of the CO2, after a first release phase, unlike what is obtained with soda.

[0152] [Tables4] Name Bituminous composition Bitumen base F3-2 F8 Type of additive / Soda + adhesion promoter Surfactant (a) Clay (Dellite 67 G] Clay (Sepiolite] Penetrability (1 / 10 mm] 41 69 67 40 40 TBA (°C] 51.8 48.2 48.1. 55.6 52.6 CO2 incorporated at the outlet of PAV % m / m compared to the bitumen base 1.03 1.16 1.40: 1.15 1.33 CO2 remaining after 5 hours at 25°C % m / m compared to the bitumen base 0.63 0.89 0.84 0.64 0.69 CO2 remaining after 24 hours at 25^0 % m / m compared to the bitumen base 0.37 0.88 0.43 0.33 0.39

[0153] (a)amine (PIBA03)

Claims

Claims

1. Bituminous composition comprising a bitumen base modified by incorporation of an alkali hydroxide, the bitumen base representing at least 72% by mass of said bituminous composition, characterized in that CO2 is trapped in said bituminous composition and represents from 0.5 to 5% by mass, preferably 0.5 to 4% by mass, and preferentially from 0.5 to 3% by mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% by mass, of the mass of bitumen base and the mass of the bituminous composition is stable at 25°C and under 1013.25 hPa, over a period Ps of at least 10 hours, preferably at least 15 hours.

2. Bituminous composition according to claim 1 characterized in that the CO2 has been trapped in the bituminous composition, following a trapping step, in particular carried out by placing said bitumen base modified by incorporation of an alkali hydroxide, in an enclosure under CO2 pressure, followed by a step of releasing part of the trapped CO2, until the mass of the bituminous composition obtained stabilizes, this stabilization occurring in particular, 3 hours or more after the end of the trapping step, in particular 5 to 10 hours after the end of the trapping step.

3. Bituminous composition according to claim 1 or 2, characterized in that the bitumen base has been modified by incorporation of 0.1 to 9% by mass, preferably 0.2 to 4.5% by mass, and preferentially 0.2 to 2% by mass of alkali hydroxide, relative to the mass of bitumen base.

4. Bituminous composition according to one of the preceding claims, characterized in that the trapped CO2 is found, at least in part, in the bituminous composition in the form of one or more reaction product(s) with the alkali hydroxide.

5. Bituminous composition according to one of the preceding claims, characterized in that the alkali hydroxide is NaOH or KOH.

6. Bituminous composition according to one of the preceding claims, characterized in that the alkali hydroxide is NaOH and at least part of the incorporated NaOH, or even all of the incorporated NaOH, has reacted with the trapped CO2 and is found, in the bituminous composition, in the form of one or more reaction products between CO2 and NaOH, in particular in the form of NaHCO3 and Na2CO3, or exclusively in the form of NaHCO3.

7. Bituminous composition according to one of claims 1 to 5, characterized in that the alkali hydroxide is KOH and at least part of the incorporated KOH, or even all of the incorporated KOH, has reacted with the trapped CO2 and is found, in the bituminous composition, in the form of one or more reaction products between CO2 and KOH, in particular in the form of KHCO3 and K2CO3, or exclusively in the form of KHCO3.

8. Bituminous composition according to one of the preceding claims, characterized in that the bitumen base represents at least 83% by mass and preferably at least 89% by mass of the total mass of the bituminous composition.

9. Bituminous composition according to one of the preceding claims, characterized in that it further comprises an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, said adhesion promoter preferably representing 0.01 to 2.5% by mass, preferentially 0.05 to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, of the mass of the bitumen base.

10. Bituminous composition according to one of the preceding claims, characterized in that it further comprises one or more polymers chosen from olefinic polymers and elastomers, in particular from olefinic polymers and crosslinked elastomers, preferably representing from 0.1 to 12% by mass, preferentially from 0.3 to 10% by mass, and even more preferably from 0.5 to 7% by mass, of the mass of the bitumen base.

11. A process for preparing a bituminous composition comprising a bitumen base representing at least 72% by mass of said bituminous composition, said process comprising the following successive steps: a) obtaining a modified bitumen base, comprising the incorporation of an alkali hydroxide into a bitumen base, said incorporation being followed or accompanied by mixing, preferably under heating at a temperature in the range from 90 to 230°C, preferably in the range from 120 to 200°C, and preferentially in the range from 120 to 180°C, b) trapping CO2 in the modified bitumen base at a mass content representing from 0.8 to 5.8% by mass, preferably from 0.5 to 4% by mass, preferentially from 0.8 to 3.5% by mass, and in such a manner that: even more preferably from 0.8 to 2.6% by mass, or from 0.8 to 1.8% by mass, of the mass of the bitumen base.

12. Preparation process according to claim 11 characterized in that the incorporation of CO2 is carried out by placing the modified bitumen base in an enclosure under CO2 pressure, the enclosure being maintained at a temperature ranging from 10 to 200°C, preferably ranging from 20 to 160°C, and preferentially ranging from 25 to 160°C, or even 80 to 160°C, the CO2 pressure being chosen in particular in the range from 5.103 to 8.104 hPa, preferably in the range from 5.103 to 5.104 hPa, and preferentially in the range from 1.104 to 3.104 hPa.

13. Preparation process according to one of claims 11 or 12, characterized in that in step a), the mass of alkali hydroxide incorporated represents from 0.1 to 9% by mass, preferably from 0.2 to 4.5%, and preferentially from 0.2 to 2% by mass, of the mass of bitumen base.

14. Preparation process according to one of claims 11 to 13, characterized in that the alkali hydroxide is NaOH or KOH.

15. Preparation process according to one of claims 11 to 14 characterized in that during step a), an adhesion promoter chosen from amines, diamines, polyamines, alkyl amido amines, amidopolyamines, imidazolines, and mixtures thereof, is also incorporated into the bitumen base, said adhesion promoter preferably being introduced at a rate of 0.01 to 2.5% by mass, preferably 0.05 to 1.1% by mass, and even more preferably 0.1 to 0.4% by mass, of the total mass of the bitumen base.

16. Preparation process according to one of claims 11 to 15, characterized in that during step a), one or more polymers chosen from olefinic polymers and elastomers, in particular from crosslinked elastomers, is (are) also incorporated into the bitumen base, said polymer(s) preferably being introduced at a rate of preferably 0.1 to 12% by mass, preferably 0.3 to 10%, and preferably 0.5 to 7% by mass, of the mass of the bitumen base.

17. Preparation process according to one of claims 11 to 16, characterized in that the bituminous composition resulting from step b) is subjected to a step of releasing part of the trapped CO2, at the end of which the mass of the bituminous composition is stable.

18. Method according to claim 17 characterized in that the release step leads to a quantity of CO2 trapped in the bituminous composition, corresponding to 0.5 to 5% by mass, preferably 0.5 to 4% in mass, and preferably from 0.5 to 3% in mass, and even more preferably from 0.5 to 2% or from 0.5 to 1.5% or from 0.7 to 2% in mass, relative to the mass of the bitumen base.

19. Use of a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 to 18, for preparing a waterproofing coating, a membrane or an impregnation layer.

20. Use of a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 to 18, for preparing a surface coating, a hot mix, a cold mix, a cold-poured mix, a gravel emulsion or a wearing course, said bituminous composition being associated with aggregates and / or recycled millings.

21. Process for preparing a coated material characterized in that it comprises the hot mixing of a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 to 18, with aggregates and / or recycled millings, and optionally mineral and / or synthetic fillers.

22. Coated material comprising a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 to 18, in a mixture with aggregates and / or recycled millings, and optionally mineral and / or synthetic fillers.

23. Process for preparing an asphalt characterized in that it comprises the hot mixing of a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 to 18, with mineral and / or synthetic fillers.

24. Method according to claim 23, characterized in that the hot mixing with the bituminous composition is carried out at a temperature of 80 to 200°C, preferably 80 to 180°C and preferentially 100 to 160°C.

25. Asphalt comprising a bituminous composition according to any one of claims 1 to 10 or capable of being obtained according to a process as defined in any one of claims 11 at 18, mixed with mineral and / or synthetic fillers.

26. Use of an alkali hydroxide in a bituminous composition in which CO2 is incorporated, to obtain stabilization of the quantity of CO2 remaining trapped within said bituminous composition.

Images