A multi-self-repairing modified asphalt based on photo-thermal filler and dynamic hydrogen bond material and a preparation method thereof

Abstract

The application discloses a kind of based on photothermal filler and dynamic hydrogen bond material multiple self-repairing modified asphalt and preparation method thereof, belong to road engineering and material science technology field.The raw material of the multiple self-repairing modified asphalt based on photothermal filler and dynamic hydrogen bond material of the application includes by mass fraction:SBS modified asphalt 100 parts, photothermal filler 1-5 parts and dynamic hydrogen bond material 1-3 parts.The application aims to combine photothermal conversion mechanism and dynamic hydrogen bond self-repairing mechanism, accelerate the movement of asphalt and polymer molecular chain at crack, to improve the self-repairing ability of asphalt material, prolong the service life of asphalt pavement, and reduce the maintenance cost of asphalt pavement.The application solves the deficiency of traditional self-repairing asphalt in repair frequency, repair effect and repair durability, has excellent photothermal conversion efficiency and multiple self-repairing performance, and the repair efficiency does not appear obvious attenuation after multiple load damage-illumination repair cycle, can effectively restore mechanical properties, suitable for road construction and maintenance under different climate conditions.

Description

Technical Field

[0001] This invention relates to the fields of road engineering and materials science and technology, and in particular to a multi-stage self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonded materials and its preparation method. Background Technology

[0002] With the acceleration of urbanization and the continuous expansion of transportation networks, the frequency of use and load levels of asphalt pavements have increased significantly, leading to more severe challenges for road materials. Traditional asphalt pavements, during long-term service, are susceptible to aging, oxidation, and crack propagation due to various external factors such as alternating high and low temperatures, ultraviolet radiation, and traffic loads. These cracks not only affect road safety but also significantly increase maintenance and repair costs. Therefore, improving the self-healing ability of asphalt materials and extending their service life has become an important research direction in the field of road materials.

[0003] Currently, researchers have proposed various conventional self-healing methods for asphalt self-healing technology. The most common methods involve incorporating microcapsules or admixtures into the asphalt to release self-healing substances (such as rejuvenators) to repair cracks when they occur. These microcapsules rupture when cracks appear, releasing the internal repair substance, which combines with the asphalt material to fill the crack and restore the asphalt's structure and properties. Another method involves introducing microwave-sensitive materials into the asphalt to heat the asphalt surrounding the crack under microwave irradiation, achieving crack closure. However, these methods typically have limitations; the repair effect is often one-time, and the repair process requires external stimulation (such as stress or microwaves), making it difficult to maintain good repair results under prolonged, high-volume traffic conditions.

[0004] While existing self-healing methods have improved the self-repairing ability of asphalt materials to some extent, most technologies suffer from limitations in the number of repairs, short-lasting repair effects, and dependence on specific environmental conditions. These shortcomings make it difficult for existing self-healing asphalt to meet the demands of high-frequency, continuous repair during long-term use, necessitating the development of more efficient and sustainable repair solutions. Photothermal fillers, such as graphene and carbon nanotubes, can rapidly absorb light energy and convert it into heat energy under sunlight, thereby locally heating the asphalt, raising its temperature, reducing its viscosity, and promoting crack healing. Although photothermal fillers have good heating performance and a certain repair effect, their repair ability is usually limited to high-temperature environments, and the number of repairs is limited, making them unable to cope with repeated and frequent damage. Dynamic hydrogen-bonded materials, as another option for self-healing technology, introduce materials with dynamic hydrogen bond exchange capabilities, enabling asphalt to heal cracks through the dynamic breaking and recombination mechanism of hydrogen bonds when cracks occur. These materials can rapidly repair cracks in their early stages through hydrogen bond exchange, improving the crack resistance of asphalt. However, existing dynamic hydrogen-bonded materials have a slow repair effect and are highly dependent on the external environment, requiring further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-stage self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonded materials, and its preparation method, to solve the aforementioned problems in the background art. This invention aims to improve the self-healing ability of asphalt materials, extend the service life of asphalt pavements, and reduce the maintenance costs of asphalt pavements by combining photothermal conversion mechanisms with dynamic hydrogen-bonded self-healing mechanisms to accelerate the movement of asphalt and polymer molecular chains at cracks.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of this invention is to provide a multi-stage self-healing modified asphalt based on photothermal fillers and dynamic hydrogen bonding materials, wherein the raw materials, by mass parts, include:

[0008] 100 parts SBS modified bitumen, 1-5 parts photothermal filler, and 1-3 parts dynamic hydrogen bonding material.

[0009] The photothermal filler of this invention can increase the local temperature of asphalt by absorbing solar energy and converting it into heat energy, reduce the viscosity of asphalt, promote the movement of asphalt molecular chains at cracks, and thus promote crack repair.

[0010] When the amount of photothermal filler added is within the range defined by this invention, it can ensure that the product has good photothermal conversion efficiency under solar light, thereby effectively repairing cracks.

[0011] The dynamic hydrogen bond material of this invention can promote the connection and action of molecular chains at the crack through the dynamic breaking and recombination mechanism of hydrogen bonds when cracks occur, enhance the movement and connection of molecular chains in asphalt, give it better healing performance, and maintain a certain self-repairing ability after the crack is healed.

[0012] Preferably, the photothermal filler is graphene and / or carbon nanotubes, which have excellent photothermal conversion effect and thermal conductivity.

[0013] Preferably, the dynamic hydrogen-bonding material includes one or more of polyurethane (PU), polyvinyl alcohol (PVA), and polyamide (PA).

[0014] Preferably, the photothermal filler undergoes the following pretreatment before use:

[0015] The photothermal filler is mixed with a sulfuric acid-nitric acid mixture and refluxed to remove impurities and introduce polar functional groups such as carboxyl and hydroxyl groups on its surface to facilitate subsequent reactions with silane coupling agents, thereby obtaining a modified photothermal filler.

[0016] The modified photothermal filler is mixed with a silane coupling agent and reacted to form a stable bond on the filler surface, thereby improving its compatibility with asphalt components.

[0017] Then, the solvent is removed by drying methods such as rotary evaporation, centrifugal filtration, and vacuum drying to obtain dried surface-modified photothermal filler.

[0018] Under high-temperature reflux, the C=C bonds at the edges and defect sites of carbon nanotubes and graphene are partially oxidized, forming polar functional groups such as carboxyl and hydroxyl groups.

[0019] Preferably, the sulfuric acid-nitric acid mixture is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1-3:1; the reflux reaction is carried out at a temperature of 50-60°C for 1-2 hours.

[0020] The silane coupling agent is KH-550 or KH-560, which needs to be pre-hydrolyzed in an ethanol / water mixture at 50°C for 30 minutes; the reaction temperature is 60°C and the time is 2-4 hours.

[0021] Preferably, the drying temperature is 40-60°C.

[0022] Preferably, the dynamic hydrogen bond material undergoes the following pretreatment before use:

[0023] The dynamic hydrogen-bonded material is dissolved in a solvent to obtain a polymer solution;

[0024] A hydrophobic long-chain modifier is added to the polymer solution to carry out a grafting reaction, thereby introducing hydrophobic groups.

[0025] A dry, modified dynamic hydrogen-bonded material with grafted long-chain hydrophobic groups was obtained through precipitation, filtration, and drying steps.

[0026] Preferably, the hydrophobic long-chain modifier contains an active group; the active group is a carboxyl group, an ester group, or an acyl chloride group; the grafting reaction is carried out under the action of a catalyst or a condensing agent; the catalyst is N,N-dimethylbenzylamine (BDMA) or tetrabutylammonium bromide (TBAB); the condensing agent is N,N'-dicyclohexylcarbodiimide (DCC); the grafting reaction is carried out at a temperature of 50-60°C for 3-6 hours.

[0027] Preferably, the solvent is a DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide) solution, etc.

[0028] After pretreatment, the oleophilicity of the dynamic hydrogen bond material is enhanced, which is beneficial to its uniform dispersion and compatibility in the asphalt system, while retaining its dynamic hydrogen bond network characteristics.

[0029] Preferably, the repeatedly self-healing modified asphalt also contains functional additives; the functional additives include one or more of toughening agents, antioxidants, and ultraviolet absorbers, used to improve the asphalt's anti-aging, anti-ultraviolet, and flexibility.

[0030] Preferably, the SBS modified bitumen serves as the matrix of the material system, providing good mechanical properties and compatibility with other repair components.

[0031] Preferably, the hydrophobic long-chain modifier is oleic acid or octadecanoic acid.

[0032] More preferably, the octadecanoic acid is stearic acid.

[0033] The second technical solution of this invention provides a method for preparing the above-mentioned self-healing modified asphalt based on photothermal fillers and dynamic hydrogen bonding materials, comprising the following steps:

[0034] The photothermal filler and dynamic hydrogen bonding material are added to SBS modified asphalt and mixed to obtain the multi-self-healing modified asphalt.

[0035] Preferably, the SBS modified asphalt is SBS modified asphalt preheated to 165-175°C.

[0036] Preferably, the mixing is performed at a shear rate of 3000-4000 rad / s for 45-60 minutes.

[0037] This invention, by controlling the mixing temperature and shear rate, can prevent overheating from causing material degradation or loss of repair properties.

[0038] The beneficial technical effects of the present invention are as follows:

[0039] This invention aims to improve the self-healing ability of asphalt materials, extend the service life of asphalt pavements, and reduce maintenance costs by combining photothermal conversion mechanisms with dynamic hydrogen bond self-healing mechanisms to accelerate the movement of asphalt and polymer molecular chains at cracks. This invention overcomes the shortcomings of traditional self-healing asphalt in terms of repair frequency, repair effect, and repair durability. It possesses excellent photothermal conversion efficiency and multiple self-healing performance. The repair efficiency does not show significant attenuation after multiple load-damage-light-repair cycles, effectively restoring mechanical properties and making it suitable for road construction and maintenance under various climatic conditions.

[0040] The composite self-healing asphalt material of this invention can effectively repair cracks under different temperature conditions, with fast repair speed, long-lasting effect, stronger adaptability and longer service life. It can significantly improve road durability and effectively reduce road maintenance costs. This material can effectively repair cracks in both normal and high temperature environments, making it particularly suitable for road construction and maintenance under different climatic conditions.

[0041] The asphalt material of this invention has a high cost-performance ratio, and the preparation process is simple and easy to industrialize. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the self-healing mechanism of the modified asphalt based on photothermal fillers and dynamic hydrogen bonding materials according to the present invention. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0045] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0046] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.

[0047] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0048] This invention discloses a multi-stage self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonding materials. The raw materials, by mass parts, include:

[0049] In the following embodiments and comparative examples of the present invention, the concentration of concentrated sulfuric acid is 98 wt% and the concentration of concentrated nitric acid is 65 wt%.

[0050] All raw materials used in the following embodiments and comparative examples of this invention are commercially available products. Graphene and multi-walled carbon nanotubes were purchased from Jiangsu Taifeng Nanomaterials Technology Co., Ltd.; polyurethane, polyvinyl alcohol, and polyamide were purchased from Shengyu New Material Technology (Shanghai) Co., Ltd.; and No. 70 base bitumen and SBS modified bitumen were purchased from China Petroleum & Chemical Corporation Refining & Sales Co., Ltd.

[0051] Figure 1 This is a schematic diagram of the self-healing mechanism of the modified asphalt based on photothermal fillers and dynamic hydrogen bonding materials according to the present invention.

[0052] Example 1

[0053] A method for preparing repeatedly self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonding materials, comprising the following steps:

[0054] S1. Surface modification of photothermal filler: Weigh 5g of graphene powder and add it to a concentrated sulfuric acid-concentrated nitric acid mixture (250mL in total) with a volume ratio of 3:1. Place it in a reflux apparatus and reflux at 60℃ for 2 hours. After cooling, wash the product repeatedly with deionized water by centrifugation until neutral to obtain graphene oxide with carboxyl and hydroxyl functional groups. Add the obtained graphene oxide and KH-550 coupling agent at a mass ratio of 1:0.2 to 30mL of ethanol / water mixture (95:5, v / v). After pre-hydrolyzing at 50℃ for 30 min, stir magnetically at 60℃ for 4 hours. Cool, centrifuge, wash 3 times with anhydrous ethanol solution, and vacuum dry at 50℃ to constant weight to obtain dry surface-modified graphene oxide powder.

[0055] S2. Surface modification of dynamic hydrogen bonded materials: Dissolve 8g of polyurethane elastomer in 100mL of DMF solution, stir and heat until completely dissolved, then add 1.2g of stearic acid, 2.0g of condensing agent DCC and 0.15g of BDMA, and react at 60℃ for 5 hours under a nitrogen atmosphere to promote the esterification / amidation reaction of stearic acid with the hydroxyl or amino groups at the chain end of polyurethane; after the reaction, cool, slowly pour the mixture into 400mL of ice water / ethanol (1:1, v / v) for precipitation, filter, wash 3 times with 50% ethanol aqueous solution, vacuum dry at 50℃ to constant weight, and obtain polyurethane powder grafted with stearic acid after pulverization and sieving.

[0056] S3. Weigh 100 parts of SBS modified asphalt, heat to 165℃, add 3 parts of the above-mentioned surface-modified graphene oxide and 2 parts of polyurethane powder grafted with stearic acid, and shear at 4000 rad / s for 60 min to prepare multi-self-healing modified asphalt.

[0057] Example 2

[0058] A method for preparing repeatedly self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonding materials, comprising the following steps:

[0059] S1. Surface modification of photothermal filler: Weigh 5g of multi-walled carbon nanotube powder and add it to a concentrated sulfuric acid-concentrated nitric acid mixture (250mL in total) with a volume ratio of 3:1. Place it in a reflux apparatus and reflux at 60℃ for 2 hours. After cooling, wash the product repeatedly with deionized water by centrifugation until neutral to obtain carboxylated carbon nanotubes. Add the obtained carboxylated carbon nanotubes and KH-550 coupling agent at a mass ratio of 1:0.2 to 30mL of ethanol / water mixture (95:5, v / v). After pre-hydrolyzing at 50℃ for 30 min, stir magnetically at 60℃ for 4 hours. Cool, centrifuge, wash three times with anhydrous ethanol, and vacuum dry at 50℃ to constant weight to obtain dried surface-modified carboxylated carbon nanotube powder.

[0060] S2. Surface modification of dynamic hydrogen bonded materials: Dissolve 8g of polyvinyl alcohol in 100mL of DMSO solution and stir and heat until completely dissolved; add 1.2g of oleic acid, 2.0g of condensing agent DCC and 0.15g of DMAP, and react at 60℃ for 5 hours under nitrogen atmosphere; after the reaction, cool and slowly pour the mixture into 400mL of ice water / ethanol (1:1, v / v) to precipitate, filter, wash 3 times with 50% ethanol aqueous solution, and vacuum dry at 50℃ to constant weight to obtain polyvinyl alcohol powder grafted with oleic acid.

[0061] S3. Weigh 100 parts of SBS modified asphalt, heat to 165℃, add 3 parts of the above-mentioned surface-modified carbon nanotube powder and 2 parts of grafted oleic acid polyvinyl alcohol powder, and shear at 4000 rad / s for 60 min to prepare multi-self-healing modified asphalt.

[0062] Comparative Example 1

[0063] The only difference from Example 1 is that the amount of surface-modified graphene oxide and polyurethane powder grafted with stearic acid added in S3 is changed to 1 part and 0.5 parts, respectively.

[0064] Comparative Example 2

[0065] The only difference from Example 1 is that the amount of surface-modified graphene oxide and polyurethane powder grafted with stearic acid added in S3 is changed to 9 parts and 6 parts, respectively.

[0066] Comparative Example 3

[0067] The only difference from Example 1 is that the addition of surface-modified graphene oxide in S3 is omitted and an equal mass of polyurethane powder grafted with stearic acid is added.

[0068] Comparative Example 4

[0069] The only difference from Example 1 is that the addition of polyurethane powder grafted with stearic acid in S3 is omitted and an equal mass of surface-modified graphene oxide is added.

[0070] Comparative Example 5

[0071] The only difference from Example 2 is that the magnetic stirring time at 60°C is changed from 4 hours to 1 hour.

[0072] Comparative Example 6

[0073] The only difference from Example 2 is that the SBS modified bitumen in S3 is replaced with an equal mass of No. 70 base bitumen.

[0074] Comparative Example 7

[0075] The only difference from Example 2 is that the high-speed shearing time was changed from 60 min to 30 min.

[0076] Effect verification

[0077] To test the self-healing properties of the recurrent self-healing modified asphalt of this invention, asphalt segregation tests and photothermal conversion efficiency tests were conducted on No. 70 base asphalt, SBS modified asphalt, self-healing modified asphalt prepared in Examples 1-2, and self-healing modified asphalt prepared in Comparative Examples 1-7. The photothermal conversion efficiency test used a near-infrared laser emitter (laser wavelength 808 nm, laser power density 1.0 W·cm²). -2 The process involves collecting the surface temperature rise of the asphalt material after 100 seconds using a thermal imager. The asphalt material effectively converts solar energy into heat energy through photothermal fillers, causing its surface temperature to rise rapidly and thus promoting crack healing.

[0078] In addition, mechanical property recovery tests and multiple self-healing tests were conducted on all the aforementioned asphalt samples. In the mechanical property recovery test, the self-healing modified asphalt underwent a force-ductility test at a temperature of 25℃ and a tensile rate of 5 mm / min. First, a tensile test was performed on the asphalt before crack formation to obtain the failure load F1. Specifically, the failure sections of the damaged specimens were combined, and repair was performed under sunlight without applying any external force. After a fixed repair time, the force-ductility test was repeated to obtain the repaired failure load F2. The self-healing efficiency of the self-healing modified asphalt was calculated using the ratio of F2 to F1. In the multiple self-healing tests, the self-healing modified asphalt specimens were placed in a three-cycle load-failure-light-repair experiment. A force-ductility test was performed after each light-repair cycle, and the self-healing efficiency after the third repair was recorded. All test results are shown in Table 1.

[0079]

[0080] In the formula, η is the self-healing efficiency, F1 represents the initial failure load, and F2 represents the failure load after repair.

[0081] Table 1. Softening point difference and self-healing efficiency of self-healing modified asphalt.

[0082]

[0083] Note: The softening point difference is the difference between the softening points of the upper and lower layers of asphalt after the asphalt segregation test. The larger the softening point difference, the worse the storage stability of the asphalt; the smaller the softening point difference, the better the storage stability of the asphalt.

[0084] According to the test data in Table 1, the self-healing efficiency of all examples and comparative examples is higher than that of ordinary No. 70 base asphalt and SBS modified asphalt, indicating that photothermal fillers and dynamic hydrogen bonding materials can improve the multiple self-healing ability of asphalt.

[0085] The self-healing modified asphalt prepared in Example 1 showed the best performance in terms of segregation control, surface photothermal response, and self-healing efficiency. This is mainly because graphene oxide has a large specific surface area and excellent infrared absorption capacity, which can effectively increase the surface temperature of the asphalt, thereby accelerating the flow and healing of materials at microcracks. Simultaneously, the grafting of stearic acid onto polyurethane segments forms a stable and high-density dynamic hydrogen bond network, endowing the material with good segment reconstruction ability and self-healing cycle stability.

[0086] Comparing Example 1 with Comparative Examples 1 and 2 allows us to explore the effect of the ratio of photothermal filler to dynamic hydrogen-bonding material on the performance of self-healing asphalt. Comparative Example 1, with its low addition amount (1 part graphene oxide + 0.5 parts polyurethane), resulted in insufficient photothermal response and dynamic hydrogen-bonding network formation in the material, limiting its self-healing ability. This manifested as a decrease in initial repair efficiency and a significant decline in cyclic repair performance. Comparative Example 2, with its excessive addition (9 parts graphene oxide + 6 parts polyurethane), despite sufficient photothermal filler, exhibited significant segregation in the asphalt, disrupting the overall uniformity and stability. This led to a significant increase in the segregation index, hindering photothermal conduction and dynamic segment reconstruction channels, thus weakening the self-healing performance.

[0087] Comparing Example 2 with Example 1, both employed a composite system of surface-coupled modified photothermal filler and dynamic hydrogen-bonded material, achieving excellent product performance. However, because the graphene oxide in Example 1 possesses relatively better photothermal conversion efficiency and dispersibility than the carboxylated carbon nanotubes in Example 2, and the hydrogen bond network constructed by polyurethane-stearic acid has a higher density and greater stability, it outperforms Example 2 in terms of surface temperature rise, self-healing efficiency, and multiple cycle repair capabilities.

[0088] Comparing Example 1 with Comparative Examples 3-4, it can be seen that Comparative Example 3, due to the absence of surface-modified graphene oxide photothermal material, does not exhibit a significant temperature rise effect under infrared light irradiation, making it difficult to effectively stimulate the reconstruction process of dynamic hydrogen bonds, resulting in a significant reduction in the self-healing performance of the material. Comparative Example 4, a polyurethane dynamic hydrogen bond material without grafted stearic acid, although possessing a certain photothermal heating effect, also exhibits lower self-healing performance than Example 1 due to the lack of sufficient hydrogen bond network within the system to support crack healing.

[0089] Comparing Example 2 with Comparative Example 5, although KH-550 coupling agent was used to treat carboxylated carbon nanotubes in Comparative Example 5, the treatment time was only 1 hour, the coupling reaction was insufficient, and the functional groups on the filler surface were not sufficiently grafted, resulting in poor dispersibility and weak interfacial compatibility in asphalt, making it difficult to fully participate in photothermal conduction and network construction, and resulting in low self-healing efficiency.

[0090] Example 2 was compared with Comparative Example 6, where the asphalt type was changed from SBS modified asphalt to ordinary No. 70 base asphalt. Due to the lack of a three-dimensional network support structure provided by the SBS polymer, although the dynamic hydrogen bonds and photothermal fillers could locally repair the cracks, the overall material viscoelasticity was insufficient, which could not support efficient thermal response and crack closure, resulting in a significant decrease in self-healing efficiency.

[0091] Example 2 was compared with Comparative Example 7, which examined the effect of the shear dispersion process on the material uniformity. Reducing the shear time from 60 minutes to 30 minutes resulted in insufficient dispersion of the photothermal filler and dynamic hydrogen bonding material in the SBS modified bitumen, weak interfacial bonding, and poor uniformity of the material's macroscopic properties. This reduced the photothermal response efficiency and the ability to build the dynamic network, which was reflected in lower surface temperature rise and repair efficiency compared to Example 2.

[0092] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A type of repeatedly self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonding materials, characterized in that, Raw materials, by mass parts, include: 100 parts SBS modified bitumen, 1-5 parts photothermal filler and 1-3 parts dynamic hydrogen bonding material; The photothermal filler is graphene and / or carbon nanotubes; The dynamic hydrogen-bonding material includes one or more of polyurethane, polyvinyl alcohol, and polyamide; The photothermal filler underwent the following pretreatment before use: The photothermal filler was mixed with a sulfuric acid-nitric acid mixture and refluxed to obtain a modified photothermal filler. The modified photothermal filler is mixed with a silane coupling agent and reacted. The dynamic hydrogen bond material underwent the following pretreatment before use: The dynamic hydrogen-bonded material is dissolved in a solvent to obtain a polymer solution; A hydrophobic long-chain modifier is added to the polymer solution to carry out a grafting reaction.

2. The reusable self-healing modified asphalt according to claim 1, characterized in that, The reflux reaction is carried out at a temperature of 50-60℃ for 1-2 hours. The silane coupling agent is KH-550 or KH-560; the reaction temperature is 60℃ and the time is 2-4 hours.

3. The reusable self-healing modified asphalt according to claim 1, characterized in that, The hydrophobic long-chain modifier contains an active group; the active group is a carboxyl group, an ester group, or an acyl chloride group; the grafting reaction is carried out under the action of a catalyst or a condensing agent; the catalyst is N,N-dimethylbenzylamine or tetrabutylammonium bromide; the condensing agent is N,N'-dicyclohexylcarbodiimide; the grafting reaction is carried out at a temperature of 50-60℃ for 3-6 hours.

4. A method for preparing repeatedly self-healing modified asphalt based on photothermal fillers and dynamic hydrogen-bonding materials as described in any one of claims 1-3, characterized in that, Includes the following steps: The photothermal filler and dynamic hydrogen bonding material are added to SBS modified asphalt and mixed to obtain the multi-self-healing modified asphalt.

5. The preparation method according to claim 4, characterized in that, The SBS modified asphalt is SBS modified asphalt preheated to 165-175℃.

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