Asphalt self-healing microcapsule with microwave response heating function and preparation method

Abstract

The invention discloses an asphalt self-healing microcapsule with a microwave response heating function and a preparation method, and belongs to the technical field of asphalt self-healing, the asphalt self-healing microcapsule comprises a core material and a wall material coating the core material; the core material is grease, the wall material is modified thermosetting resin and comprises thermosetting resin and carbon nanotubes in a mass ratio of 100: (5-10); the carbon nano tube is at least one of a hydroxylated multi-walled carbon nano tube, a carboxylated multi-walled carbon nano tube and an aminated multi-walled carbon nano tube; the preparation method comprises the steps of synthesis of a carbon nanotube modified MUF prepolymer, preparation of a core material emulsion, core material wrapping through a condensation polymerization reaction and the like. Microcapsules are doped into matrix asphalt according to the mass part ratio of (1-5): 100 to form modified asphalt, and under microwave irradiation, carbon nanotubes efficiently absorb heat to quickly heat the interior of the asphalt, promote release of a core material and accelerate crack repair, so that active regulation and control of the self-healing performance of the asphalt are realized, and the technical problem of low repair efficiency in a low-temperature environment is solved; the service life of the asphalt pavement can be effectively prolonged, and the engineering application value is important.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt self-healing technology, and in particular to an asphalt self-healing microcapsule with microwave responsive heating function and a preparation method thereof. Background Art

[0002] Currently, asphalt mixtures are commonly used for road pavement. However, over time, asphalt ages due to environmental influences, becoming hard and brittle, making it more susceptible to cracking under vehicle loads. Asphalt possesses a certain degree of self-healing properties, but these properties are poor at room temperature, making it unable to completely repair self-cracks. Therefore, measures are needed to promote this self-healing behavior.

[0003] Currently, many approaches are being developed to enhance the self-healing properties of asphalt, including core-shell self-healing microcapsules with polymer walls and a rejuvenating agent as the core. However, due to the uneven distribution of the microcapsules within the asphalt mixture, the rejuvenating agent released from the microcapsules cannot quickly penetrate and repair cracks at room temperature. Therefore, it is urgent to adopt measures to promote the diffusion of the asphalt rejuvenating agent in the microcapsules to more quickly repair cracks in asphalt and effectively extend the service life of asphalt pavements. Summary of the Invention

[0004] To address the challenges of existing technologies, the present invention provides microwave-responsive self-healing asphalt microcapsules and their preparation method. By introducing multi-walled carbon nanotubes (MWCNTs) into the microcapsule preparation process, the microcapsules are endowed with microwave-responsive heating capabilities. When these microcapsules are added to an asphalt mixture, the internal temperature rises within a short microwave exposure time, promoting the release and penetration of the core material, accelerating crack healing and extending the service life of the asphalt pavement.

[0005] The present invention is achieved through the following technical solutions: An asphalt self-healing microcapsule with microwave responsive heating function, comprising a core material and a wall material covering the core material; The core material is grease, and the wall material is modified thermosetting resin, including thermosetting resin and carbon nanotubes, with a mass ratio of 100:(5-10).

[0006] Preferably, the carbon nanotubes are at least one of hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes and amino multi-walled carbon nanotubes.

[0007] Preferably, the thermosetting resin is MUF resin.

[0008] A method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, comprising the following steps: Step 1: uniformly mixing MUF prepolymer and carbon nanotubes to obtain carbon nanotube-modified MUF prepolymer; Step 2: Mix the core material emulsion with the carbon nanotube-modified MUF prepolymer in a mass ratio of 1:(1-2) and adjust to acidity, and then carry out a condensation reaction to allow the prepolymer to wrap the core material to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

[0009] Preferably, the preparation method of the MUF prepolymer is as follows: Melamine, urea and formaldehyde are uniformly mixed in a molar ratio of 1:(2-3):(7-13) to obtain a mixed solution A. The mixed solution A is adjusted to alkaline and reacted in a water bath to obtain a MUF prepolymer.

[0010] Preferably, the temperature of the water bath reaction is 70° C. and the time is 1 hour.

[0011] Preferably, the preparation method of the carbon nanotube-modified MUF prepolymer is as follows: MUF prepolymer, carbon nanotubes and solvent were uniformly mixed in a mass ratio of 1:1:1 to obtain carbon nanotube-modified MUF prepolymer.

[0012] Preferably, the preparation method of the core material solution is as follows: The oil and the sodium dodecylbenzenesulfonate solution were mixed evenly at a mass ratio of 1:10, and the mixture was sheared in a water bath to obtain a core material emulsion.

[0013] Preferably, the polycondensation reaction method of the core material emulsion and the carbon nanotube-modified MUF prepolymer is as follows: The mixed solution of the core material emulsion and the carbon nanotube-modified MUF prepolymer was reacted for more than 3 hours under a 65° C. water bath heating condition to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

[0014] A modified asphalt comprises base asphalt and asphalt self-healing microcapsules with microwave-responsive heating function, with the mass fraction being (1-5):100.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This application provides a microwave-responsive heating-enabled self-healing microcapsule for asphalt. Carbon nanotubes (CNTs) (mass ratio 100:5-10) are introduced into the wall material of a modified thermosetting resin (such as MUF resin). This imparts excellent microwave absorption to the microcapsules, allowing them to rapidly heat up under microwave irradiation, significantly accelerating the release and diffusion of the core material (grease), thereby significantly improving the self-healing efficiency of asphalt cracks. The optimized material ratio balances microwave responsiveness with cost-effectiveness, avoiding dispersion issues caused by excessive CNTs. The dense and stable wall structure ensures uniform distribution of the microcapsules within the asphalt and precisely controls the timing of core material release. The core material is made of a widely available grease (such as vegetable oil or mineral oil), which is highly compatible with asphalt and effectively replenishes the lightweight components of aged asphalt, extending the life of the pavement. Compared to traditional microcapsules, this invention's microwave-responsive heating function addresses the challenges of slow core material release and insufficient penetration at room temperature, significantly shortening crack repair time.

[0016] The modified asphalt of the present application, the microcapsule wall material introduced in the modified asphalt contains carbon nanotubes, which can efficiently absorb microwave energy and convert it into heat energy under microwave irradiation, quickly increase the internal temperature of the asphalt, and promote the release, flow and diffusion of the core material (such as oil and fat regeneration agent), thereby accelerating the penetration and repair process of cracks. Compared with the traditional microcapsule's passive release of the core material by relying on the ambient temperature, the present invention significantly shortens the core material release time through an active microwave response heating mechanism, and can effectively trigger self-healing behavior even in low-temperature environments, solving the technical bottleneck of low self-healing efficiency under normal temperature conditions. Secondly, the microcapsule wall material adopts a modified thermosetting resin (such as MUF resin) and carbon nanotubes. It not only enhances the mechanical strength and heat resistance of the microcapsules, but also optimizes the distribution uniformity of the microcapsules in the asphalt through the uniform dispersion of carbon nanotubes, avoiding the problem of uneven performance caused by aggregation of traditional microcapsules. Furthermore, the ratio of core material to wall material (1:1-2 by mass) and the proportion of carbon nanotubes added (5-10% by mass of wall material) have been scientifically optimized to ensure both the stability of the microcapsules during asphalt mixture processing and the efficient thermal response during microwave heating. Test data from Examples 4-6 further demonstrates their superiority: under 700W microwave irradiation, the modified asphalt with microcapsules (such as Examples 4-6) exhibited a temperature difference exceeding 10°C relative to the base asphalt within 60 seconds. This temperature difference continued to increase with increasing microwave exposure, demonstrating significant microwave-responsive heating. This efficient thermal energy release not only accelerates the release rate of the core material but also softens the asphalt matrix through localized heating, promoting the integration of the rejuvenator into the aged asphalt, thereby more thoroughly repairing cracks and restoring material properties. Furthermore, the addition of core material to the microcapsules effectively compensates for the loss of lightweight components in the asphalt due to long-term aging, slowing the hardening and embrittlement process, further extending the service life of the pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a curve diagram showing the relationship between microwave heating time and temperature difference for different asphalts of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0021] In response to the problem in the background technology that microcapsules are unevenly distributed inside the asphalt mixture and the regeneration agent released by the microcapsules under normal temperature conditions cannot quickly penetrate and repair cracks, the present application provides an asphalt self-healing microcapsule with microwave responsive heating function. By introducing microwave absorbing material multi-walled carbon nanotubes during the microcapsule preparation process, the microcapsule has a microwave responsive heating function, thereby increasing the internal temperature of the asphalt mixture and accelerating the healing process of asphalt cracks.

[0022] The present application provides a core material and a wall material covering the core material; The core material is grease, and the wall material is modified thermosetting resin, including thermosetting resin and carbon nanotubes, with a mass ratio of 100:(5-10).

[0023] In some embodiments, the mass ratio of the core material to the wall material is 1:(1-2).

[0024] Optionally, the core material is grease, including natural vegetable oil, mineral oil and modified grease.

[0025] Natural vegetable oils include castor oil, linseed oil, soybean oil, and palm oil.

[0026] Mineral oils include paraffin oil, petrolatum, polyalphaolefins, and silicone oils.

[0027] Modified oils include epoxidized soybean oil, chlorinated paraffins, and microcrystalline waxes.

[0028] In some embodiments, the carbon nanotubes are at least one of hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, and amino multi-walled carbon nanotubes.

[0029] In some embodiments, the thermosetting resin is a MUF resin.

[0030] Correspondingly, the present application also provides a method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, comprising the following steps: Step 1: uniformly mixing MUF prepolymer and carbon nanotubes to obtain carbon nanotube-modified MUF prepolymer; S1, preparing MUF prepolymer; 1) Melamine, urea and formaldehyde are mixed uniformly in a molar ratio of 1:(2-3):(7-13) to obtain a mixed solution A.

[0031] 2) Adjust the mixed solution A to alkaline; Add 10% triethanolamine solution to the mixture and adjust the pH value to between 8 and 9; 3) The alkaline mixed solution A is reacted in a water bath to obtain a MUF prepolymer.

[0032] The alkaline mixed solution A was stirred and reacted in a water bath at 70°C for 1 hour to obtain a MUF prepolymer; S2, mixing MUF prepolymer with carbon nanotubes; The MUF prepolymer, carbon nanotubes and solvent were uniformly mixed in a mass ratio of 1:1:1 to obtain a carbon nanotube-modified MUF prepolymer.

[0033] Step 2: preparing a core material solution; The oil and 7% sodium dodecylbenzenesulfonate solution were mixed evenly at a mass ratio of 1:10, and the mixture was sheared in a water bath to obtain a core material emulsion; Step 3: Mix the core material emulsion with the carbon nanotube-modified MUF prepolymer in a mass ratio of 1:(1-2) and adjust to acidity, and then carry out a polycondensation reaction to allow the prepolymer to undergo a polycondensation reaction to wrap the core material, thereby obtaining asphalt self-healing microcapsules with microwave-responsive heating function.

[0034] Example 1 A method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, comprising the following steps: Step 1, preparing carbon nanotube modified MUF prepolymer; 1) mixing a mixture of melamine, urea, formaldehyde and hydroxylated multi-walled carbon nanotubes with distilled water in a mass ratio of 1:1 to obtain a mixed solution; Among them, the molar ratio of melamine, urea and formaldehyde is 1:3:9.

[0035] 2) Add 10% triethanolamine solution to the mixed solution and adjust the pH value to between 8; 3) The mixed solution was dispersed using an ultrasonic disperser for 30 minutes to allow the carboxylated multi-walled carbon nanotubes to be evenly distributed in the solution; 4) The mixed solution was stirred and reacted in a water bath at 70°C for 1 hour to prepare a carbon nanotube-modified MUF prepolymer; Step 2, preparing a core material emulsion; Soybean oil and 7% sodium dodecylbenzenesulfonate solution were mixed at a mass ratio of 1:10, and sheared using a high-speed shearing machine at a speed of 1000 rpm in a 50°C water bath for 30 minutes to prepare a core material emulsion; Step 2: preparing asphalt self-healing microcapsules with microwave-responsive heating function; The core material emulsion and carbon nanotube-modified MUF prepolymer were mixed in a mass ratio of 1:2, and the pH value of the mixed solution was adjusted to between 3 and 3.5 using 5% citric acid solution. The mixed solution was allowed to react for more than 3 hours using a magnetic stirrer in a 65°C water bath. The obtained product was filtered through a 500-mesh filter and dried in a 50°C oven for 24 hours to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

[0036] Example 2 A method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, comprising the following steps: Step 1, preparing carbon nanotube modified MUF prepolymer; 1) mixing a mixture of melamine, urea, formaldehyde and hydroxylated multi-walled carbon nanotubes with distilled water in a mass ratio of 1:1 to obtain a mixed solution; The molar ratio of melamine, urea and formaldehyde is 1:2:7.

[0037] 2) Add 10% triethanolamine solution to the mixed solution and adjust the pH value to between 9; 3) The mixed solution was dispersed using an ultrasonic disperser for 30 minutes to uniformly distribute the amino-modified multi-walled carbon nanotubes in the mixed solution; 4) The mixed solution was stirred and reacted in a water bath at 70°C for 1 hour to prepare a carbon nanotube-modified MUF prepolymer; Step 2, preparing a core material emulsion; Castor oil and 7% sodium dodecylbenzenesulfonate solution were mixed at a mass ratio of 1:10, and sheared using a high-speed shearing machine at a speed of 1000 rpm in a 50°C water bath for 30 minutes to prepare a core material emulsion; Step 2: preparing asphalt self-healing microcapsules with microwave-responsive heating function; The core material emulsion and carbon nanotube-modified MUF prepolymer were mixed in a mass ratio of 1:1, and the pH value of the mixed solution was adjusted to between 3 and 3.5 using 5% citric acid solution. The mixed solution was allowed to react for more than 3 hours using a magnetic stirrer in a 65°C water bath. The obtained product was filtered through a 500-mesh filter and dried in a 50°C oven for 24 hours to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

[0038] Example 3 A method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, comprising the following steps: Step 1, preparing carbon nanotube modified MUF prepolymer; 1) mixing a mixture of melamine, urea, formaldehyde and hydroxylated multi-walled carbon nanotubes with distilled water in a mass ratio of 1:1 to obtain a mixed solution; Among them, the molar ratio of melamine, urea and formaldehyde is 1:5:13.

[0039] 2) Add 10% triethanolamine solution to the mixed solution and adjust the pH value to between 9; 3) The mixed solution was dispersed using an ultrasonic disperser for 30 minutes to uniformly distribute the amino-modified multi-walled carbon nanotubes in the mixed solution; 4) The mixed solution was stirred and reacted in a water bath at 70°C for 1 hour to prepare a carbon nanotube-modified MUF prepolymer; Step 2, preparing a core material emulsion; Paraffin oil and 7% sodium dodecylbenzenesulfonate solution were mixed at a mass ratio of 1:10, and sheared using a high-speed shearing machine at a speed of 1000 rpm in a 50°C water bath for 30 minutes to prepare a core material emulsion; Step 2: preparing asphalt self-healing microcapsules with microwave-responsive heating function; The core material emulsion and carbon nanotube-modified MUF prepolymer were mixed in a mass ratio of 1:1.5, and the pH value of the mixed solution was adjusted to between 3 and 3.5 using 5% citric acid solution. The mixed solution was allowed to react for more than 3 hours using a magnetic stirrer in a 65°C water bath. The obtained product was filtered through a 500-mesh filter and dried in a 50°C oven for 24 hours to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

[0040] Based on the above-mentioned asphalt self-healing microcapsules with microwave responsive heating function, the present application also provides a modified asphalt based on the asphalt self-healing microcapsules with microwave responsive heating function, including matrix asphalt and asphalt self-healing microcapsules with microwave responsive heating function, with the mass fraction being (1-5):100.

[0041] When cracks appear within the asphalt pavement, the core material in the microcapsules is released to fill the cracks, replenishing the lightweight components lost through long-term aging. Furthermore, the microwave-responsive multi-walled carbon nanotubes (MWCNTs) introduced into the microcapsules raise the internal temperature under microwave irradiation, promoting the release and flow of the core material, as well as its integration with the existing asphalt, accelerating the self-healing process.

[0042] Correspondingly, the present application also provides a modified asphalt based on the asphalt self-healing microcapsules with microwave responsive heating function, and the preparation method is as follows: Step 1: adding 1-5 parts by mass of asphalt self-healing microcapsules with microwave-responsive heating function to 100 parts of molten matrix asphalt to obtain mixed asphalt; Step 2: Under the heat preservation state, the mixed asphalt is mechanically stirred to obtain modified asphalt.

[0043] Example 4 A modified asphalt based on the asphalt self-healing microcapsules with microwave responsive heating function, the preparation method is as follows: Step 1: Add 1 part of asphalt self-healing microcapsules with microwave-responsive heating function to 100 parts of molten matrix asphalt to obtain mixed asphalt; In the asphalt self-healing microcapsules with microwave-responsive heating function, the mass ratio of the core material emulsion to the carbon nanotube-modified MUF prepolymer is 1:1; the mass ratio of the carboxylated multi-walled carbon nanotubes to the MUF prepolymer in the carbon nanotube-modified MUF prepolymer is 5:100.

[0044] Step 2: Under the heat preservation state, the mixed asphalt is mechanically stirred to obtain modified asphalt.

[0045] The holding temperature was 160° C. and the mixture was stirred at 000 rpm for 30 min.

[0046] Example 5 A modified asphalt based on the asphalt self-healing microcapsules with microwave responsive heating function, the preparation method is as follows: Step 1: Add 3 parts by mass of asphalt self-healing microcapsules with microwave-responsive heating function to 100 parts of molten matrix asphalt to obtain mixed asphalt; In the asphalt self-healing microcapsules with microwave-responsive heating function, the mass ratio of the core material emulsion to the carbon nanotube-modified MUF prepolymer is 1:1; the mass ratio of the hydroxylated multi-walled carbon nanotubes in the carbon nanotube-modified MUF prepolymer to the MUF prepolymer is 5:100; and the molar ratio of melamine, urea and formaldehyde in the MUF prepolymer is 1:3:9.

[0047] Step 2: Under the heat preservation state, the mixed asphalt is mechanically stirred to obtain modified asphalt.

[0048] The holding temperature was 170° C. and the mixture was stirred at 000 rpm for 30 min.

[0049] Example 6 A modified asphalt based on the asphalt self-healing microcapsules with microwave responsive heating function, the preparation method is as follows: Step 1: Add 5 parts by mass of asphalt self-healing microcapsules with microwave-responsive heating function to 100 parts of molten matrix asphalt to obtain mixed asphalt; In the asphalt self-healing microcapsules with microwave-responsive heating function, the mass ratio of the core material emulsion to the carbon nanotube-modified MUF prepolymer is 1:1; the mass ratio of the amino-modified multi-walled carbon nanotubes to the MUF prepolymer in the carbon nanotube-modified MUF prepolymer is 5:100; and the molar ratio of melamine, urea and formaldehyde in the MUF prepolymer is 1:3:9.

[0050] Step 2: Under the heat preservation state, the mixed asphalt is mechanically stirred to obtain modified asphalt.

[0051] The holding temperature was 160° C. and the mixture was stirred at 000 rpm for 30 min.

[0052] The microwave heating rate of the modified asphalt provided in this application is tested below. The heating rates of the base asphalt and the three modified asphalts prepared in Examples 4 to 6 under the action of microwaves were tested.

[0053] Four types of asphalt were poured into glass dishes with a radius of 60 mm, with 15 grams of asphalt in each dish. First, an infrared thermal imager was used to measure the initial surface temperature T0 of the asphalt in the glass dish. The glass dish was then placed in a microwave oven with a frequency of 2.45 GHz and a power of 700 W and microwave-heated for 30 seconds, 60 seconds, 90 seconds, 120 seconds, 150 seconds, and 180 seconds. The infrared thermal imager was then used again to measure the surface temperature T' of the asphalt in the glass dish after microwave heating. The temperature difference T'-T0 was calculated, and the temperature difference of the four types of asphalt and the microwave heating time were obtained. Figure 1 .

[0054] A larger temperature difference indicates a greater increase in the internal temperature of the asphalt after microwave heating. After 60 seconds of microwave exposure, the temperature difference in Example 1 was over 10°C higher than that of the base asphalt, demonstrating excellent microwave heating efficiency. The temperature difference between Examples 2 and 3 was also 5°C higher than that of the base asphalt after 150 seconds of microwave heating. Therefore, the microcapsules prepared by the present invention exhibit excellent microwave-responsive heating.

[0055] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A self-healing asphalt microcapsule with microwave responsive heating function, characterized in that: Including core material and wall material covering the core material; The core material is grease, and the wall material is modified thermosetting resin, including thermosetting resin and carbon nanotubes, with a mass ratio of 100:(5-10).

2. The asphalt self-healing microcapsule with microwave responsive heating function according to claim 1, characterized in that: The carbon nanotubes are at least one of hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes and aminoated multi-walled carbon nanotubes.

3. The asphalt self-healing microcapsule with microwave responsive heating function according to claim 1, characterized in that: The thermosetting resin is MUF resin.

4. A method for preparing asphalt self-healing microcapsules with microwave-responsive heating function, characterized in that: The following steps are involved: Step 1: uniformly mixing MUF prepolymer and carbon nanotubes to obtain carbon nanotube-modified MUF prepolymer; Step 2: Mix the core material emulsion with the carbon nanotube-modified MUF prepolymer in a mass ratio of 1:(1-2) and adjust to acidity, and then carry out a condensation reaction to allow the prepolymer to wrap the core material to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

5. The method for preparing asphalt self-healing microcapsules with microwave-responsive heating function according to claim 4, characterized in that: The preparation method of the MUF prepolymer is as follows: Melamine, urea and formaldehyde are uniformly mixed in a molar ratio of 1:(2-3):(7-13) to obtain a mixed solution A. The mixed solution A is adjusted to alkaline and reacted in a water bath to obtain a MUF prepolymer.

6. The method for preparing asphalt self-healing microcapsules with microwave-responsive heating function according to claim 5, characterized in that: The temperature of the water bath reaction is 70° C. and the reaction time is 1 hour.

7. The method for preparing asphalt self-healing microcapsules with microwave-responsive heating function according to claim 4, characterized in that: The preparation method of the carbon nanotube modified MUF prepolymer is as follows: MUF prepolymer, carbon nanotubes and solvent were uniformly mixed in a mass ratio of 1:1:1 to obtain carbon nanotube-modified MUF prepolymer.

8. The method for preparing asphalt self-healing microcapsules with microwave-responsive heating function according to claim 4, characterized in that: The preparation method of the core material solution is as follows: The oil and the sodium dodecylbenzenesulfonate solution were mixed evenly at a mass ratio of 1:10, and the mixture was sheared in a water bath to obtain a core material emulsion.

9. The method for preparing asphalt self-healing microcapsules with microwave-responsive heating function according to claim 4, characterized in that: The polycondensation reaction method of the core material emulsion and the carbon nanotube modified MUF prepolymer is as follows: The mixed solution of the core material emulsion and the carbon nanotube-modified MUF prepolymer was reacted for more than 3 hours under a 65° C. water bath heating condition to obtain asphalt self-healing microcapsules with microwave-responsive heating function.

10. A modified asphalt, characterized in that: The invention comprises matrix asphalt and asphalt self-healing microcapsules with microwave responsive heating function as described in any one of claims 1 to 4, with the mass fraction being (1-5):100.

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