Self-repairing microcapsule modified asphalt pavement material and preparation method thereof

Abstract

The invention relates to the technical field of asphalt pavements, and particularly discloses a self-repairing microcapsule modified asphalt pavement material and a preparation method of the self-repairing microcapsule modified asphalt pavement material. Under the triggering of an external magnetic field, the microcapsule can actively crack to release the capsule core to repair the asphalt pavement crack without depending on the condition that the stress at the tip of the crack reaches a threshold value to cover the complete-cycle repair requirement of the pavement microcrack from the initial formation stage to the expansion stage, so that the timeliness of crack healing is greatly improved, and the service life of the pavement is prolonged; the fiber powder reinforcing layer adopts KH-560 modified basalt fiber powder, has the characteristics of high strength and high modulus, and is uniformly adsorbed on the surface of the magnetic sensitive capsule wall to form a compact reinforcing layer, so that the self-repairing microcapsule is prevented from being broken and failed in advance, and the tensile strength and the shear strength can be improved through participation of the fiber powder when the self-repairing microcapsule is broken in a crack; and the service life of the repaired asphalt pavement is prolonged.

Description

Technical Field

[0001] This invention relates to the field of asphalt pavement technology, and in particular to a self-healing microcapsule modified asphalt pavement material and its preparation method. Background Technology

[0002] Currently, asphalt pavement dominates global road construction due to its advantages of comfortable driving, convenient construction, and low maintenance costs. However, as a viscoelastic material, asphalt is prone to microcracks during long-term service due to the combined effects of multiple factors such as vehicle load, temperature cycle, rainwater erosion, and ultraviolet aging. These microcracks are difficult to detect in their early stages but will continue to expand into macro-cracks, potholes, and other road defects, leading to a decrease in pavement load-bearing capacity, reduced driving safety, and even a shortened service life.

[0003] In existing technologies, when asphalt cracks, microcapsules rupture under the stress at their tips, releasing the core material with repair function. The core material flows to the asphalt surrounding the microcracks through free permeation, diffusion, and capillary action, thereby achieving the purpose of microcrack healing.

[0004] However, in existing technologies, the self-healing of microcapsules requires the tip stress to reach the microcapsule threshold before they will rupture and heal the cracks. This can only achieve passive healing and cannot achieve active rupture healing. Summary of the Invention

[0005] The purpose of this invention is to provide a self-healing microcapsule modified asphalt pavement material and its preparation method, aiming to solve the technical problem in the prior art that the self-healing of microcapsules requires the microcapsule to rupture and heal cracks only when the stress at the tip reaches the microcapsule threshold, which can only achieve passive healing and cannot achieve active crack healing.

[0006] To achieve the above objectives, the present invention employs a self-healing microcapsule modified asphalt pavement material, comprising the following components by mass: 100 parts base bitumen, 4-9 parts self-healing microcapsules, 3-5 parts SBS modifier, 1-2 parts nano silica, and 10-15 parts mineral powder; The self-healing microcapsule is composed of, from the inside out, a core of 45-60% by mass, a transition layer of 5-10%, a magnetically sensitive capsule wall of 15-32%, a fiber powder reinforcing layer of 8-15%, and a rubber layer of 2-8%.

[0007] The core is composed of a composite repair agent and magnetocaloric functional particles in a mass ratio of 10:0.5~1.2. The composite repair agent is composed of refined waste edible oil, catalytic cracking slurry oil, and epoxidized soybean oil in a mass ratio of 5:3~4:2~3. The magnetocaloric functional particles are KH-550 modified Fe3O4 nanoparticles.

[0008] The transition layer is composed of styrene-butadiene rubber and asphalt modifier in a mass ratio of 4:1~2.

[0009] The fiber powder reinforcement layer is KH-560 modified basalt fiber powder with a surface hydroxyl content of 30%.

[0010] The magnetic sensing capsule wall is composed of a rigid layer and a flexible layer in a mass ratio of 3:2~3. The rigid layer is composed of 88~92% melamine-formaldehyde resin and 8~12% nano-kaolin, and the flexible layer is composed of 80~85% chlorinated rubber and 15~20% nano-Fe3O4.

[0011] The base asphalt is either 70# asphalt or 90# asphalt.

[0012] This invention also provides a method for preparing a self-healing microcapsule-modified asphalt pavement material, which includes the following steps: Preparation of self-healing microcapsules; Heat the base bitum to 160~170℃ until it melts and hold the temperature for 30 minutes; Add SBS modifier to the base bitumen and shear at 8000~10000 rpm for 30 min; Then add nano-silica and mineral powder, and stir at 160~170℃ for 20 minutes; Add the self-healing microcapsules and stir at a low speed of 200-300 rpm for 15 minutes.

[0013] The preparation of the self-healing microcapsules includes the following steps: Prepare the capsule core; Styrene-butadiene rubber and asphalt modifier are dissolved in anhydrous ethanol in a certain proportion and stirred to prepare a bonding layer solution with a mass fraction of 10-15%. The prepared core is slowly added to the bonding layer solution and sheared for 10-15 minutes at a speed of 8000-10000 rpm using a high-speed shearing machine to form a core droplet with a coating transition layer. Polyvinyl alcohol (PVA) with a mass fraction of 1-2% was added to deionized water. The temperature was raised to 60-70°C and stirred until completely dissolved. The pH of the system was adjusted to 4.0-4.5 using dilute hydrochloric acid to obtain an aqueous system. Melamine-formaldehyde resin and nano-kaolin were mixed evenly in a certain proportion and slowly added to the aqueous system. After stirring for 10 minutes, capsule core droplets with a transition layer were added and the temperature was raised to 75-85°C. The reaction was maintained for 1-1.5 hours. Melamine-formaldehyde resin polymerized on the surface of the capsule core droplets to form a rigid layer. A mixed emulsion of chlorinated rubber and nano-Fe3O4 was then added to the above system. The temperature was controlled at 75-85°C and the reaction was maintained for 2-2.5 hours. A flexible layer polymerized on the surface of the rigid layer. After washing and drying, a microcapsule intermediate coated with a magnetically sensitive capsule wall was obtained. KH-560 modified basalt fiber powder was added to anhydrous ethanol and ultrasonically dispersed for 30 min to prepare a fiber powder dispersion with a mass fraction of 5-8%. The microcapsule intermediate coated with the magnetic capsule wall was added to the fiber powder dispersion and stirred at a low speed of 300-500 rpm for 40-60 min to make the fiber powder uniformly adsorbed on the surface of the microcapsule intermediate coated with the magnetic capsule wall. Then, it was filtered and vacuum dried at 60-70℃ for 1.5-2 h to obtain microcapsules with a fiber powder reinforcement layer. Nitrile rubber was added to anhydrous ethanol, and then 0.5-1% of KH-570 silane coupling agent by weight of nitrile rubber was added. The mixture was stirred at 50-60℃ and 500-800 rpm for 30-40 minutes to prepare a rubber latex with a mass fraction of 8-12%. Microcapsules coated with fiber powder reinforcement were added to the rubber latex and stirred at low speed of 300-400 rpm for 30-45 minutes. The coated microcapsules were filtered to remove excess rubber latex, and then vacuum dried and shaped to finally obtain self-healing microcapsules.

[0014] The mass ratio of the microcapsules coated with the fiber powder reinforcement layer to the rubber latex is 1:2~3.

[0015] The preparation of the capsule core includes the following steps: Weigh out the refined waste edible oil, catalytic cracking slurry oil and epoxidized soybean oil according to the proportions; Weigh the raw materials and add them to the reaction vessel. Heat the mixture to 40-50°C and stir at 300-500 rpm for 30 minutes to fully mix the components. Add KH-550 modified Fe3O4 nanoparticles, turn on the ultrasonic dispersion device, disperse at 500~800W for 20~30min to obtain the core.

[0016] The present invention discloses a self-healing microcapsule modified asphalt pavement material and its preparation method, which has the following beneficial effects: 1. Overcoming the limitations of passive healing, through the synergistic effect of the magnetothermal function of KH-550 modified Fe3O4 nanoparticles in the core and the magnetically sensitive capsule wall, the microcapsule can actively rupture and release the core to repair asphalt pavement cracks under the trigger of an external magnetic field. An alternating magnetic field can be used for triggering, without relying on the stress at the crack tip to reach a threshold. It covers the full cycle repair needs of pavement microcracks from the initial formation stage to the expansion stage, greatly improving the timeliness of crack healing and extending the service life of the pavement. 2. The self-healing microcapsule adopts a five-layer composite structure consisting of a core, a transition layer, a magnetically sensitive capsule wall, a fiber powder reinforcement layer, and a rubber layer. The transition layer enhances the structural stability of the core and the magnetically sensitive capsule wall. The rigid and flexible layers of the magnetically sensitive capsule wall balance structural strength and toughness. The fiber powder reinforcement layer improves mechanical properties, and the rubber layer optimizes compatibility with the base asphalt. The synergistic effect of the multi-layer structure can prevent the microcapsule from rupturing prematurely under construction shear and vehicle load conditions, ensuring accurate release of the core when repair is needed and improving the reliability of the self-healing system. The fiber powder reinforcement layer uses KH-560 modified basalt fiber powder, which has high strength and high modulus characteristics. It is uniformly adsorbed on the surface of the magnetically sensitive capsule wall to form a dense reinforcement layer, preventing the self-healing microcapsule from rupturing and failing prematurely. Furthermore, the fiber powder can also improve tensile and shear strength by participating in crack rupture, extending the service life of the asphalt pavement after repair. 3. The composite repair agent uses refined waste edible oil, catalytic cracking slurry, and epoxidized soybean oil, all of which are environmentally friendly raw materials. This allows for resource recycling and, in conjunction with magnetothermal functional particles, improves crack repair efficiency. Combined with SBS modifier and nano-silica components, it not only achieves self-healing function but also enhances the crack resistance, aging resistance, and load-bearing capacity of asphalt pavement, balancing environmental efficiency with the overall performance of the pavement. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0018] Figure 1 This is a flowchart of the preparation method of a self-healing microcapsule modified asphalt pavement material according to the present invention. Detailed Implementation

[0019] This invention provides a self-healing microcapsule-modified asphalt pavement material, comprising the following components by mass: 100 parts base bitumen, 4-9 parts self-healing microcapsules, 3-5 parts SBS modifier, 1-2 parts nano silica, and 10-15 parts mineral powder; The self-healing microcapsule is composed of, from the inside out, a core of 45-60% by mass, a transition layer of 5-10%, a magnetically sensitive capsule wall of 15-32%, a fiber powder reinforcing layer of 8-15%, and a rubber layer of 2-8%.

[0020] Furthermore, the core is composed of a composite repair agent and magnetocaloric functional particles in a mass ratio of 10:0.5~1.2. The composite repair agent is composed of refined waste edible oil, catalytic cracking slurry oil, and epoxidized soybean oil in a mass ratio of 5:3~4:2~3. The magnetocaloric functional particles are KH-550 modified Fe3O4 nanoparticles.

[0021] Furthermore, the transition layer is composed of styrene-butadiene rubber and asphalt modifier in a mass ratio of 4:1~2.

[0022] Furthermore, the fiber powder reinforcement layer is KH-560 modified basalt fiber powder with a surface hydroxyl content of 30%.

[0023] Furthermore, the magnetic sensing capsule wall is composed of a rigid layer and a flexible layer in a mass ratio of 3:2~3. The rigid layer is composed of 88~92% melamine-formaldehyde resin and 8~12% nano-kaolin, and the flexible layer is composed of 80~85% chlorinated rubber and 15~20% nano-Fe3O4.

[0024] Furthermore, the base asphalt is either 70# asphalt or 90# asphalt.

[0025] This invention also provides a method for preparing a self-healing microcapsule-modified asphalt pavement material, which includes the following steps: S1: Preparation of self-healing microcapsules; S2: Heat the base asphalt to 160~170℃ to melt and hold for 30 minutes; S3: Add SBS modifier to the base bitumen and shear at 8000~10000 rpm for 30 min; S4: Add nano-silica and mineral powder, and stir at 160~170℃ for 20 minutes; S5: Add self-healing microcapsules and stir at low speed of 200~300rpm for 15min.

[0026] Furthermore, the preparation of the self-healing microcapsules includes the following steps: S11: Prepare the capsule core; S12: Dissolve styrene-butadiene rubber and asphalt modifier in anhydrous ethanol in proportion, stir to prepare a bonding layer solution with a mass fraction of 10~15%, slowly add the prepared core to the bonding layer solution, and use a high-speed shearing machine to shear at a speed of 8000~10000rpm for 10~15min to form a core droplet with a coating transition layer. S13: Add polyvinyl alcohol (PVA) to deionized water at a mass fraction of 1-2%, heat to 60-70°C, and stir until completely dissolved. Adjust the pH of the system to 4.0-4.5 using dilute hydrochloric acid to obtain an aqueous phase system. Mix melamine-formaldehyde resin and nano-kaolin in a specific ratio and slowly add to the aqueous phase system. Stir for 10 minutes, then add the core droplet coated with the transition layer and heat to 75-85°C. Keep the temperature for 1-1.5 hours. The melamine-formaldehyde resin polymerizes on the surface of the core droplet to form a rigid layer. Then add a mixed emulsion of chlorinated rubber and nano-Fe3O4 to the above system, control the temperature to 75-85°C, and continue the reaction for 2-2.5 hours. The rigid layer polymerizes on the surface to form a flexible layer. After washing and drying, a microcapsule intermediate coated with a magnetically sensitive capsule wall is obtained. S14: Add KH-560 modified basalt fiber powder to anhydrous ethanol and ultrasonically disperse for 30 min to prepare a fiber powder dispersion with a mass fraction of 5-8%. Add the microcapsule intermediate coated with the magnetic capsule wall to the fiber powder dispersion and stir at a low speed of 300-500 rpm for 40-60 min to make the fiber powder uniformly adsorbed on the surface of the microcapsule intermediate coated with the magnetic capsule wall. Then filter and vacuum dry at 60-70℃ for 1.5-2 h to obtain microcapsules with a fiber powder reinforcement layer. S15: Add nitrile rubber to anhydrous ethanol, then add 0.5~1% of KH-570 silane coupling agent by weight of nitrile rubber, and stir at 50~60℃ and 500~800rpm for 30~40min to prepare a rubber latex with a mass fraction of 8~12%. Add microcapsules coated with fiber powder reinforcement layer to the rubber latex, and stir at low speed of 300~400rpm for 30~45min. Filter the coated microcapsules and remove excess rubber latex. Vacuum dry and shape to finally obtain self-healing microcapsules.

[0027] Furthermore, the mass ratio of the microcapsules coated with the fiber powder reinforcement layer to the rubber latex is 1:2~3.

[0028] Furthermore, the preparation of the capsule core includes the following steps: S111: Weigh out refined waste edible oil, catalytic cracking slurry oil and epoxidized soybean oil in proportion; S112: Weigh the raw materials and add them to the reactor. Heat the reactor to 40-50°C and stir at 300-500 rpm for 30 minutes to fully mix the components. S113: Add KH-550 modified Fe3O4 nanoparticles, turn on the ultrasonic dispersion device, disperse at 500~800W for 20~30min to obtain the core.

[0029] In this embodiment, A method for preparing a self-healing microcapsule-modified asphalt pavement material includes the following steps: Weigh out the refined waste edible oil, catalytic cracking slurry oil and epoxidized soybean oil according to the proportions; Weigh the raw materials and add them to the reaction vessel. Heat the mixture to 40-50°C and stir at 300-500 rpm for 30 minutes to fully mix the components. Add KH-550 modified Fe3O4 nanoparticles, turn on the ultrasonic dispersion device, disperse at 500~800W for 20~30min to obtain the core. Styrene-butadiene rubber and asphalt modifier are dissolved in anhydrous ethanol in a certain proportion and stirred to prepare a bonding layer solution with a mass fraction of 10-15%. The prepared core is slowly added to the bonding layer solution and sheared for 10-15 minutes at a speed of 8000-10000 rpm using a high-speed shearing machine to form a core droplet with a coating transition layer. Polyvinyl alcohol (PVA) with a mass fraction of 1-2% was added to deionized water. The temperature was raised to 60-70°C and stirred until completely dissolved. The pH of the system was adjusted to 4.0-4.5 using dilute hydrochloric acid to obtain an aqueous system. Melamine-formaldehyde resin and nano-kaolin were mixed evenly in a certain proportion and slowly added to the aqueous system. After stirring for 10 minutes, capsule core droplets with a transition layer were added and the temperature was raised to 75-85°C. The reaction was maintained for 1-1.5 hours. Melamine-formaldehyde resin polymerized on the surface of the capsule core droplets to form a rigid layer. A mixed emulsion of chlorinated rubber and nano-Fe3O4 was then added to the above system. The temperature was controlled at 75-85°C and the reaction was maintained for 2-2.5 hours. A flexible layer polymerized on the surface of the rigid layer. After washing and drying, a microcapsule intermediate coated with a magnetically sensitive capsule wall was obtained. KH-560 modified basalt fiber powder was added to anhydrous ethanol and ultrasonically dispersed for 30 min to prepare a fiber powder dispersion with a mass fraction of 5-8%. The microcapsule intermediate coated with the magnetic capsule wall was added to the fiber powder dispersion and stirred at a low speed of 300-500 rpm for 40-60 min to make the fiber powder uniformly adsorbed on the surface of the microcapsule intermediate coated with the magnetic capsule wall. Then, it was filtered and vacuum dried at 60-70℃ for 1.5-2 h to obtain microcapsules with a fiber powder reinforcement layer. Nitrile rubber was added to anhydrous ethanol, and then 0.5-1% of KH-570 silane coupling agent by mass of nitrile rubber was added. The mixture was stirred at 50-60℃ and 500-800 rpm for 30-40 minutes to prepare a rubber latex with a mass fraction of 8-12%. Microcapsules coated with fiber powder reinforcement were added to the rubber latex and stirred at low speed of 300-400 rpm for 30-45 minutes. The coated microcapsules were filtered to remove excess rubber latex, and then vacuum dried and shaped to finally obtain self-healing microcapsules. Heat the base bitum to 160~170℃ until it melts and hold the temperature for 30 minutes; Add SBS modifier to the base bitumen and shear at 8000~10000 rpm for 30 min; Then add nano-silica and mineral powder, and stir at 160~170℃ for 20 minutes; Add the self-healing microcapsules and stir at a low speed of 200-300 rpm for 15 minutes.

[0030] The core is made from recycled raw materials such as refined waste cooking oil and catalytic cracking slurry, combined with epoxidized soybean oil. This reduces resource waste and environmental burden, while the synergistic effect with magnetocaloric functional particles ensures repair effectiveness, balancing environmental value and practical performance. A transition layer strengthens the bond between the core and the capsule wall, the magnetically sensitive capsule wall balances strength and toughness, a fiber-reinforced layer forms a dense protective shell to prevent premature microcapsule rupture, and a rubber layer optimizes compatibility with the matrix asphalt. This multi-layered structure ensures the integrity of the microcapsules during construction and service, enabling precise core release during repair. When repairing cracks, the fiber... The bridging effect enhances the tensile and shear strength of the pavement; combined with a stepwise mixing process of SBS modifier, nano-silica, and mineral powder, the functional components are evenly dispersed, which not only enhances the crack resistance, aging resistance, and load-bearing capacity of the asphalt pavement, but also extends the service life of the repaired pavement. This preparation method combines self-healing function with optimization of the basic performance of asphalt pavement, which not only solves the limitations of traditional passive repair, but also achieves simultaneous improvement in self-healing efficiency, mechanical properties, and aging resistance through the synergistic effect of each component, significantly extending the overall service life of the asphalt pavement and reducing maintenance costs.

[0031] Example 1: The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Example 2: The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Example 3: The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Comparative Example 1 (without self-healing microcapsules): The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: Comparative Example 2 (without magnetothermal particles): The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Comparative Example 3 (No Fiber Powder Reinforced Layer): The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Comparative Example 4 (Single capsule wall): The components of the self-healing microcapsule modified asphalt pavement material are shown in the table below: The components of the self-healing microcapsules are shown in the table below: The components of the capsule core are shown in the table below: Test results and comparative analysis of Examples 1-3 and Comparative Examples 1-4: Self-healing microcapsules are the only carriers that can achieve crack healing and synergistically enhance mechanical properties and anti-aging properties. The active triggering mechanism of magnetocaloric particles and magnetically sensitive capsule walls is the key to efficient repair. Passive repair cannot cover early microcracks. Fiber powder reinforcement layers are necessary for achieving complete self-healing and structural stability. Without these layers, the capsule core is prone to leakage and the healing is not dense. The magnetically sensitive capsule wall, through a composite structure of rigid and flexible layers, is the core that balances stability and magnetic response. A single capsule wall is too brittle and cannot accurately trigger self-healing. Through the synergistic design of "active magnetic triggering mechanism + five-layer composite microcapsule structure + environmentally friendly composite repair agent", the unity of self-healing efficiency, mechanical properties, structural stability and environmental protection is achieved. Through different matching of Examples 1 to 3, it can be applied to asphalt pavements of different types or uses to meet the needs of different scenarios.

[0032] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A self-healing microcapsule-modified asphalt pavement material, characterized in that, Includes the following mass components: 100 parts base bitumen, 4-9 parts self-healing microcapsules, 3-5 parts SBS modifier, 1-2 parts nano silica, and 10-15 parts mineral powder; The self-healing microcapsule is composed of, from the inside out, a core of 45-60% by mass, a transition layer of 5-10%, a magnetically sensitive capsule wall of 15-32%, a fiber powder reinforcing layer of 8-15%, and a rubber layer of 2-8%.

2. The self-healing microcapsule modified asphalt pavement material as described in claim 1, characterized in that, The core is composed of a composite repair agent and magnetothermal functional particles in a mass ratio of 10:0.5~1.

2. The composite repair agent is composed of refined waste edible oil, catalytic cracking slurry oil and epoxidized soybean oil in a mass ratio of 5:3~4:2~3. The magnetothermal functional particles are KH-550 modified Fe3O4 nanoparticles.

3. The self-healing microcapsule modified asphalt pavement material as described in claim 1, characterized in that, The transition layer is composed of styrene-butadiene rubber and asphalt modifier in a mass ratio of 4:1~2.

4. The self-healing microcapsule modified asphalt pavement material as described in claim 1, characterized in that, The fiber powder reinforcement layer is KH-560 modified basalt fiber powder with a surface hydroxyl content of 30%.

5. The self-healing microcapsule modified asphalt pavement material as described in claim 1, characterized in that, The magnetic sensing capsule wall is composed of a rigid layer and a flexible layer in a mass ratio of 3:2~3. The rigid layer is composed of 88~92% melamine-formaldehyde resin and 8~12% nano-kaolin, and the flexible layer is composed of 80~85% chlorinated rubber and 15~20% nano-Fe3O4.

6. The self-healing microcapsule modified asphalt pavement material as described in claim 1, characterized in that, The base asphalt is either 70# asphalt or 90# asphalt.

7. A method for preparing a self-healing microcapsule-modified asphalt pavement material, used to prepare the self-healing microcapsule-modified asphalt pavement material as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Preparation of self-healing microcapsules; Heat the base bitum to 160~170℃ until melted and hold at that temperature for 30 minutes; Add SBS modifier to the base bitumen and shear at 8000~10000 rpm for 30 min; Then add nano-silica and mineral powder, and stir at 160~170℃ for 20 minutes; Add the self-healing microcapsules and stir at a low speed of 200-300 rpm for 15 minutes.

8. The method for preparing self-healing microcapsule modified asphalt pavement material as described in claim 7, wherein the preparation of self-healing microcapsules is characterized in that, Includes the following steps: Prepare the capsule core; Styrene-butadiene rubber and asphalt modifier are dissolved in anhydrous ethanol in a certain proportion and stirred to prepare a bonding layer solution with a mass fraction of 10-15%. The prepared core is slowly added to the bonding layer solution and sheared for 10-15 minutes at a speed of 8000-10000 rpm using a high-speed shearing machine to form a core droplet with a coating transition layer. Polyvinyl alcohol (PVA) with a mass fraction of 1-2% was added to deionized water. The temperature was raised to 60-70°C and stirred until completely dissolved. The pH of the system was adjusted to 4.0-4.5 using dilute hydrochloric acid to obtain an aqueous system. Melamine-formaldehyde resin and nano-kaolin were mixed evenly in a certain proportion and slowly added to the aqueous system. After stirring for 10 minutes, capsule core droplets with a transition layer were added and the temperature was raised to 75-85°C. The reaction was maintained for 1-1.5 hours. Melamine-formaldehyde resin polymerized on the surface of the capsule core droplets to form a rigid layer. A mixed emulsion of chlorinated rubber and nano-Fe3O4 was then added to the above system. The temperature was controlled at 75-85°C and the reaction was maintained for 2-2.5 hours. A flexible layer polymerized on the surface of the rigid layer. After washing and drying, a microcapsule intermediate coated with a magnetically sensitive capsule wall was obtained. KH-560 modified basalt fiber powder was added to anhydrous ethanol and ultrasonically dispersed for 30 min to prepare a fiber powder dispersion with a mass fraction of 5-8%. The microcapsule intermediate coated with the magnetic capsule wall was added to the fiber powder dispersion and stirred at a low speed of 300-500 rpm for 40-60 min to make the fiber powder uniformly adsorbed on the surface of the microcapsule intermediate coated with the magnetic capsule wall. Then, it was filtered and vacuum dried at 60-70℃ for 1.5-2 h to obtain microcapsules with a fiber powder reinforcement layer. Nitrile rubber was added to anhydrous ethanol, and then 0.5-1% of KH-570 silane coupling agent by weight of nitrile rubber was added. The mixture was stirred at 50-60℃ and 500-800 rpm for 30-40 minutes to prepare a rubber latex with a mass fraction of 8-12%. Microcapsules coated with fiber powder reinforcement were added to the rubber latex and stirred at low speed of 300-400 rpm for 30-45 minutes. The coated microcapsules were filtered to remove excess rubber latex, and then vacuum dried and shaped to finally obtain self-healing microcapsules.

9. The preparation method of the self-healing microcapsule modified asphalt pavement material as described in claim 7, characterized in that, The mass ratio of the microcapsules coated with the fiber powder reinforcement layer to the rubber latex is 1:2~3.

10. The method for preparing self-healing microcapsule modified asphalt pavement material as described in claim 7, wherein the formulation of the capsule core is characterized in that, Includes the following steps: Weigh out the refined waste edible oil, catalytic cracking slurry oil and epoxidized soybean oil according to the proportions; Weigh the raw materials and add them to the reaction vessel. Heat the mixture to 40-50°C and stir at 300-500 rpm for 30 minutes to fully mix the components. Add KH-550 modified Fe3O4 nanoparticles, turn on the ultrasonic dispersion device, disperse at 500~800W for 20~30min to obtain the core.

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