Wear-resistant recycled asphalt concrete and preparation method and application thereof

Abstract

The present application relates to the technical field of concrete, and particularly discloses a wear-resistant recycled asphalt concrete as well as a preparation method and application thereof.The wear-resistant recycled asphalt concrete provided by the present application significantly improves surface wear resistance and wear resistance by compounding raw materials, and can improve service life from multiple aspects such as high-temperature anti-rutting and low-temperature anti-cracking, and is suitable for high-wear areas such as urban intersections and bus lanes.The content of recycled asphalt pavement material is increased, and the consumption of primary resources is greatly reduced.Lignin hard carbon microspheres, hydroxyapatite and polyphosphate can form a ternary synergistic system, the lignin hard carbon microspheres can be used as micro-rolling balls to fill the voids of the mortar and bear shear stress, the hydroxyapatite can further enhance the wear resistance of the surface layer of the mixture, and the polyphosphate can break the long chain of carbonyl / sulfoxide groups in the aged asphalt in the RAP, and cooperates with the recycling agent to effectively activate the aged asphalt in the RAP and restore the rheological properties thereof.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and in particular to a wear-resistant recycled asphalt concrete, its preparation method, and its application. Background Technology

[0002] With the continuous advancement of infrastructure construction in my country and the large-scale entry of early-built roads into their maintenance cycle, a large amount of reclaimed asphalt pavement (RAP) urgently needs to be disposed of. Traditional disposal methods such as landfill or simple stockpiling not only occupy land resources but may also cause environmental pollution. Recycling RAP into new asphalt mixtures is an important way to achieve resource recycling, reduce engineering costs, and reduce carbon emissions.

[0003] However, existing recycled asphalt concrete still faces many challenges in practical applications. On the one hand, the aged asphalt in RAP is brittle and has poor adhesion, which easily leads to a decrease in the low-temperature crack resistance, fatigue performance, and water stability of the recycled mixture. On the other hand, in areas with heavy traffic or high wear (such as intersections, toll stations, and long longitudinal slopes), recycled asphalt pavements often exhibit insufficient wear resistance and weak rutting resistance, which limits their promotion and application in high-grade or high-stress road sections.

[0004] Although existing research has improved the performance of recycled asphalt mixtures by adding recycling agents, warm mix additives, fibers, or polymers to modify the asphalt, technical bottlenecks still exist in balancing high RAP content, workability, and long-term wear resistance and durability. Therefore, there is an urgent need to develop a wear-resistant recycled asphalt concrete that combines excellent wear resistance, good road performance, and high environmental benefits to expand the application scope of recycled materials in high-performance pavement engineering. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a wear-resistant recycled asphalt concrete, its preparation method, and its application. By introducing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate, the wear resistance of the concrete is effectively enhanced. Furthermore, the lignin hard carbon microspheres can adsorb free radicals and catalyze metal ions through their porous structure, thereby delaying the secondary oxidation of asphalt and improving the fatigue and aging resistance of the concrete.

[0006] To achieve the above-mentioned objectives, the embodiments of the present invention employ the following technical solutions:

[0007] In a first aspect, a wear-resistant recycled asphalt concrete comprises the following raw materials in weight percentages: 20%–35% recycled asphalt pavement material, 45%–55% coarse aggregate, 8%–15% fine aggregate, 3%–6% mineral powder, 4.2%–5.8% new matrix asphalt, 0.25%–0.5% recycling agent, 0.3%–1.2% lignin hard carbon microspheres, 0.2%–0.8% hydroxyapatite, and 0.05%–0.3% polyphosphate.

[0008] Compared to existing technologies, the wear-resistant recycled asphalt concrete provided by this invention, through the scientific compounding of recycled asphalt pavement material (RAP) with various functional components, can increase the RAP content to 20%~35% while ensuring high performance, significantly reducing the consumption of primary resources and the amount of waste pavement material landfilled. The introduced lignin hard carbon microspheres, hydroxyapatite, and polyphosphate can form a ternary synergistic system. The lignin hard carbon microspheres have high hardness and regular spherical structure, which can act as micro-balls to fill the voids in the mortar and withstand shear stress. Hydroxyapatite, as a natural high-hardness mineral phase, further enhances the wear resistance of the mixture surface. Polyphosphate can break the carbonyl / sulfoxide long chains of aged asphalt in RAP, and work synergistically with the regenerator to achieve simultaneous regeneration of "chemical bond breaking-component recombination", effectively activating the aged asphalt in RAP and restoring its rheological properties.

[0009] Preferably, the preparation method of the lignin hard carbon microspheres includes the following steps: hydrothermal carbonization treatment of lignin suspension, solid-liquid separation, drying, and obtaining the precursor;

[0010] The precursor is subjected to high-temperature carbonization treatment to obtain carbides;

[0011] The carbide was impregnated in a silane coupling agent solution for surface modification to obtain lignin hard carbon microspheres.

[0012] The high-temperature carbonization treatment is carried out at a temperature of 800℃~1200℃.

[0013] Preferably, the concentration of the lignin suspension is 3%wt to 8%wt; the reaction conditions for the hydrothermal carbonization treatment are: 180℃ to 220℃ for 4 to 12 hours; and the duration of the high-temperature carbonization treatment is 1 to 3 hours.

[0014] In this invention, lignin is first pre-constructed into a spherical skeleton through hydrothermal carbonization, and then further graphitized through high-temperature carbonization, so that the microspheres obtain higher hardness and a layered conductive skeleton. The hard carbon microspheres after surface graphitization have low surface energy and interlayer slip characteristics. When the horizontal force of the tire is applied to the road surface, the microspheres undergo nanoscale rolling and shear-induced orientation at the aggregate-mortar interface, converting macroscopic shear displacement into microsphere rotation and interlayer slip, effectively dispersing the peak value of interfacial shear stress, thereby inhibiting aggregate spalling and mortar abrasion, and significantly delaying the wear process of the surface layer of the wheel track.

[0015] Preferably, the surface modification temperature is 10~40℃ and the surface modification time is 2~6h.

[0016] More preferably, the reaction conditions for the surface modification are: reaction at 200-400 rpm for 2-6 hours.

[0017] Preferably, the silane coupling agent in the silane coupling agent solution is at least one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane, and the concentration of the silane coupling agent solution is 1%wt to 5%wt; the mass-to-volume ratio of the carbide to the silane coupling agent solution is 1g:10~20mL.

[0018] In this invention, the compatibility between lignin hard carbon microspheres modified with silane coupling agent and asphalt is significantly enhanced. Furthermore, the porous structure can adsorb free radicals and catalyze metal ions, thereby delaying the secondary oxidation of asphalt and improving the fatigue resistance and aging resistance of the mixture.

[0019] Preferably, the coarse aggregate is one or more of basalt crushed stone, diabase crushed stone, ceramic particles, or steel slag; the fine aggregate is manufactured sand; and the mineral powder is at least one of limestone ore powder or hydrated lime powder.

[0020] Preferably, the regenerator is an aromatic oil, SBS-modified soft asphalt, or a vegetable oil-based regenerator.

[0021] Preferably, the polyphosphate is one or more of sodium tripolyphosphate, sodium hexametaphosphate, potassium polyphosphate, or ammonium polyphosphate.

[0022] In this invention, polyphosphates can slowly release phosphate ions (PO4) in humid service environments. 3- ), and the calcium source in the system (such as Ca dissolved from mineral powder or hydroxyapatite) 2+ The reaction generates nano-sized hydroxyapatite microcrystals in situ, continuously strengthening the aggregate-asphalt interface, forming a dynamic wear-resistant protective layer, and extending the service life of the pavement.

[0023] Secondly, the present invention provides a method for preparing the wear-resistant recycled asphalt concrete described in the above technical solution, comprising the following steps:

[0024] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0025] Heat the recycled asphalt pavement material, coarse aggregate and fine aggregate to 145℃~165℃ and dry mix for 25~35 seconds.

[0026] Add the new base asphalt and recycling agent, and wet mix for 60-90 seconds;

[0027] Then add mineral powder and the composite functional filler, and continue mixing for 45~60s to obtain wear-resistant recycled asphalt concrete.

[0028] Thirdly, the present invention provides the application of the wear-resistant recycled asphalt concrete described in the above technical solution or the wear-resistant recycled asphalt concrete prepared by the preparation method of the wear-resistant recycled asphalt concrete described in the above technical solution in the surface layer of urban roads.

[0029] The beneficial effects of this invention are:

[0030] The wear-resistant recycled asphalt concrete provided by this invention significantly improves surface wear resistance and abrasion resistance through the compounding of raw materials, and also extends service life from multiple perspectives, such as high-temperature rutting resistance and low-temperature crack resistance. The lignin hard carbon microspheres and hydroxyapatite in the concrete produce a synergistic effect, further reducing Kentucky abrasion loss in the wear-resistant recycled asphalt concrete, making it particularly suitable for high-wear areas such as urban intersections and bus lanes. Polyphosphates can break the carbonyl / sulfoxide long chains of aged asphalt in RAP, and when used in combination with recycling agents, significantly improve the activation efficiency of aged asphalt in RAP, increasing the amount of recycled asphalt pavement material incorporated. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] Unless otherwise specified, all materials used in this invention are commercially available products.

[0033] Example 1

[0034] This embodiment provides a wear-resistant recycled asphalt concrete, the raw materials of which are 35%wt of recycled asphalt pavement material (RAP), 45%wt of coarse aggregate (basalt crushed stone and steel slag in a mass ratio of 3:1), 10%wt of fine aggregate (manufactured sand), 4%wt of limestone powder, 4.5%wt of new matrix asphalt, 0.5%wt of recycling agent (SBS modified soft asphalt), 0.4%wt of lignin hard carbon microspheres, 0.3%wt of hydroxyapatite, and 0.3%wt of polyphosphate (sodium tripolyphosphate).

[0035] The preparation method of the above-mentioned lignin hard carbon microspheres includes the following steps:

[0036] A 5% wt lignin suspension was subjected to hydrothermal carbonization at 200℃ for 8 hours. The precipitate was then collected and dried to obtain the precursor.

[0037] The precursor was subjected to high-temperature carbonization treatment at 1000℃ for 2 hours, followed by surface modification: the high-temperature carbonized precursor was immersed in 3%wt γ-aminopropyltriethoxysilane solution at a mass-volume ratio of 1g:15mL and reacted at 250rpm for 3 hours to obtain lignin hard carbon microspheres.

[0038] The above-mentioned method for preparing wear-resistant recycled asphalt concrete includes the following steps:

[0039] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0040] Heat the recycled asphalt pavement material, coarse aggregate, and fine aggregate to 155°C and dry mix for 30 seconds.

[0041] Add the new base asphalt and recycling agent, and mix wet for 80 seconds;

[0042] Add mineral powder and the aforementioned composite functional filler, and continue mixing for 60 seconds to obtain wear-resistant recycled asphalt concrete.

[0043] Example 2

[0044] This embodiment provides a wear-resistant recycled asphalt concrete, comprising 30%wt of recycled asphalt pavement material (RAP), 45%wt of coarse aggregate (diabase crushed stone and steel slag in a mass ratio of 2:1), 12%wt of fine aggregate, 6%wt of limestone powder, 5%wt of new matrix asphalt, 0.3%wt of recycling agent (SBS modified soft asphalt), 1%wt of lignin hard carbon microspheres, 0.5%wt of hydroxyapatite, and 0.2%wt of polyphosphate (sodium tripolyphosphate).

[0045] The preparation method of the above-mentioned lignin hard carbon microspheres includes the following steps:

[0046] A 5% wt lignin suspension was subjected to hydrothermal carbonization at 180℃ for 12 h. The precipitate was then collected and dried to obtain the precursor.

[0047] The precursor was subjected to high-temperature carbonization treatment at 1200℃ for 1 h, followed by surface modification: the high-temperature carbonized precursor was immersed in 1% wt γ-glycidoxypropyltrimethoxysilane solution at a mass-volume ratio of 1 g: 20 mL and reacted at 300 rpm for 3 h to obtain lignin hard carbon microspheres.

[0048] The above-mentioned method for preparing wear-resistant recycled asphalt concrete includes the following steps:

[0049] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0050] Heat the recycled asphalt pavement material, coarse aggregate, and fine aggregate to 145°C and dry mix for 30 seconds.

[0051] Add the new base asphalt and recycling agent, and wet mix for 90 seconds;

[0052] Add mineral powder and the aforementioned composite functional filler, and continue mixing for 45 seconds to obtain wear-resistant recycled asphalt concrete.

[0053] Example 3

[0054] This embodiment provides a wear-resistant recycled asphalt concrete, comprising 20%wt of recycled asphalt pavement material (RAP), 55%wt of coarse aggregate (ceramic particles and steel slag in a 1:1 mass ratio), 15%wt of fine aggregate (manufactured sand), 4%wt of hydrated lime powder, 4.2%wt of new matrix asphalt, 0.25%wt of recycling agent (aromatic oil), 1.2%wt of lignin hard carbon microspheres, 0.3%wt of hydroxyapatite, and 0.05%wt of polyphosphate (sodium hexametaphosphate).

[0055] The preparation method of the above-mentioned lignin hard carbon microspheres includes the following steps:

[0056] A 3% wt lignin suspension was subjected to hydrothermal carbonization at 220℃ for 4 hours. The precipitate was then collected and dried to obtain the precursor.

[0057] The precursor was subjected to high-temperature carbonization treatment at 800℃ for 3 hours, followed by surface modification: the high-temperature carbonized precursor was immersed in 5%wt γ-aminopropyltriethoxysilane solution at a mass-volume ratio of 1g:10mL and reacted at 400rpm for 2 hours to obtain lignin hard carbon microspheres.

[0058] The above-mentioned method for preparing wear-resistant recycled asphalt concrete includes the following steps:

[0059] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0060] Heat the recycled asphalt pavement material, coarse aggregate, and fine aggregate to 165°C and dry mix for 25 seconds.

[0061] Add the new base asphalt and recycling agent, and mix wet for 60 seconds;

[0062] Add mineral powder and the aforementioned composite functional filler, and continue mixing for 60 seconds to obtain wear-resistant recycled asphalt concrete.

[0063] Example 4

[0064] This embodiment provides a wear-resistant recycled asphalt concrete, comprising 25%wt of recycled asphalt pavement material, 49%wt of coarse aggregate (basalt crushed stone, ceramic particles and steel slag in a mass ratio of 2:1:1), 12.5%wt of fine aggregate (manufactured sand), 6%wt of limestone powder, 5.2%wt of new matrix asphalt, 0.4%wt of rejuvenator (vegetable oil-based rejuvenator), 1%wt of lignin hard carbon microspheres, 0.8%wt of hydroxyapatite, and 0.1%wt of polyphosphate (potassium polyphosphate).

[0065] The preparation method of the above-mentioned lignin hard carbon microspheres includes the following steps:

[0066] An 8% wt lignin suspension was subjected to hydrothermal carbonization at 200℃ for 8 hours. The precipitate was then collected and dried to obtain the precursor.

[0067] The precursor was subjected to high-temperature carbonization treatment at 800℃ for 2 hours, followed by surface modification: the high-temperature carbonized precursor was immersed in 5% wt γ-aminopropyltriethoxysilane solution at a mass-volume ratio of 1g:15mL and reacted at 300rpm for 3 hours to obtain lignin hard carbon microspheres.

[0068] The above-mentioned method for preparing wear-resistant recycled asphalt concrete includes the following steps:

[0069] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0070] Heat the recycled asphalt pavement material, coarse aggregate, and fine aggregate to 145°C and dry mix for 35 seconds.

[0071] Add the new base asphalt and recycling agent, and wet mix for 90 seconds;

[0072] Add mineral powder and the aforementioned composite functional filler, and continue mixing for 60 seconds to obtain wear-resistant recycled asphalt concrete.

[0073] Example 5

[0074] This embodiment provides a wear-resistant recycled asphalt concrete, comprising 35%wt of recycled asphalt pavement material, 45%wt of coarse aggregate (diabase crushed stone, ceramic particles and steel slag in a mass ratio of 2:1:1), 10%wt of fine aggregate (manufactured sand), 3%wt of mineral powder, 5.8%wt of new matrix asphalt, 0.5%wt of recycling agent (SBS modified asphalt), 0.3%wt of lignin hard carbon microspheres, 0.2%wt of hydroxyapatite, and 0.2%wt of polyphosphate (ammonium polyphosphate).

[0075] The preparation method of the above-mentioned lignin hard carbon microspheres includes the following steps:

[0076] An 8% wt lignin suspension was subjected to hydrothermal carbonization at 200℃ for 8 hours. The precipitate was then collected and dried to obtain the precursor.

[0077] The precursor was subjected to high-temperature carbonization treatment at 800℃ for 2 hours, followed by surface modification: the high-temperature carbonized precursor was immersed in 3% wt γ-glycidoxypropyltrimethoxysilane solution at a mass-volume ratio of 1 g: 15 mL and reacted at 300 rpm for 3 hours to obtain lignin hard carbon microspheres.

[0078] The above-mentioned method for preparing wear-resistant recycled asphalt concrete includes the following steps:

[0079] A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate.

[0080] Heat the recycled asphalt pavement material, coarse aggregate, and fine aggregate to 145°C and dry mix for 35 seconds.

[0081] Add the new base asphalt and recycling agent, and wet mix for 90 seconds;

[0082] Add mineral powder and the aforementioned composite functional filler, and continue mixing for 60 seconds to obtain wear-resistant recycled asphalt concrete.

[0083] Comparative Example 1

[0084] This comparative example provides a wear-resistant recycled asphalt concrete, whose composition and preparation method are similar to those of Example 1, except that the lignin hard carbon microspheres are not surface modified, and the preparation method includes the following steps:

[0085] An 8% wt lignin suspension was subjected to hydrothermal carbonization at 200℃ for 8 hours. The precipitate was then collected, dried, and the precursor was obtained. The precursor was then subjected to high-temperature carbonization at 800℃ for 2 hours to obtain lignin hard carbon microspheres.

[0086] The remaining conditions are the same as in Example 1, and will not be repeated here.

[0087] Comparative Example 2

[0088] This comparative example provides a wear-resistant recycled asphalt concrete, the preparation method of which is similar to that of Example 1, except that polyphosphate is replaced with an equal mass of recycling agent. Specifically, the raw materials are: 35%wt recycled asphalt pavement material (RAP), 45%wt coarse aggregate (basalt crushed stone and steel slag in a mass ratio of 3:1), 10%wt fine aggregate (manufactured sand), 4%wt limestone powder, 4.5%wt new matrix asphalt, 0.8%wt recycling agent (SBS modified soft asphalt), 0.4%wt lignin hard carbon microspheres, and 0.3%wt hydroxyapatite. All other conditions are the same as in Example 1 and will not be repeated.

[0089] Comparative Example 3

[0090] This comparative example provides a wear-resistant recycled asphalt concrete, the preparation method of which is similar to that of Example 1, except that lignin hard carbon microspheres are replaced with an equal mass of hydroxyapatite. Specifically, the raw materials are: 35%wt recycled asphalt pavement material (RAP), 45%wt coarse aggregate (basalt crushed stone and steel slag in a mass ratio of 3:1), 10%wt fine aggregate (manufactured sand), 4%wt limestone powder, 4.5%wt new matrix asphalt, 0.5%wt recycling agent (SBS modified soft asphalt), 0.7%wt hydroxyapatite, and 0.3%wt polyphosphate (sodium tripolyphosphate). All other conditions are the same as in Example 1 and will not be repeated.

[0091] Comparative Example 4

[0092] This comparative example provides a wear-resistant recycled asphalt concrete, the preparation method of which is similar to that of Example 1, except that hydroxyapatite is replaced with an equal mass of lignin hard carbon microspheres. Specifically, the raw materials are: 35%wt recycled asphalt pavement material (RAP), 45%wt coarse aggregate (basalt crushed stone and steel slag in a mass ratio of 3:1), 10%wt fine aggregate (manufactured sand), 4%wt limestone powder, 4.5%wt new matrix asphalt, 0.5%wt recycling agent (SBS modified soft asphalt), 0.7%wt lignin hard carbon microspheres, and 0.3%wt polyphosphate (sodium tripolyphosphate). All other conditions are the same as in Example 1 and will not be repeated.

[0093] Comparative Example 5

[0094] This comparative example provides a wear-resistant recycled asphalt concrete, whose raw materials and preparation method are similar to those of Example 1, except that hydroxyapatite is replaced with ordinary apatite without hydroxyl groups. All other conditions are the same as in Example 1 and will not be repeated.

[0095] Verification test

[0096] The recycled asphalt concrete prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests. Construction characteristics were tested according to JTG E20 T 0705. Surface abrasion resistance was tested according to the Kentucky scattering test of asphalt mixtures in JTG E20 T 0734-2011. Freeze-thaw splitting test and immersion Marshall test were determined according to JTG E20 T 0729–2011. Long-term aging durability was determined according to JTG E20 T 0630 / T 0628. Dynamic stability was determined according to JTG E20 T 0719–2011, with test specimens of 300mm*300mm*50mm, a test temperature of 60℃, a wheel load of 0.7MPa, and a repeated wheel load time of 60min. Dynamic shear rheological tests were conducted according to JTG E20 T 0628–2011. Low-temperature bending tests were conducted according to JTG E20 T 0715–2011. Bending beam rheological tests were conducted according to JTG E20 T 0627–2011. The test results are shown in Tables 1 to 3.

[0097] Table 1. Test results of construction characteristics and abrasion resistance of recycled asphalt concrete.

[0098]

[0099] Table 2. Test results of high-temperature deformation resistance and low-temperature crack resistance of recycled asphalt concrete.

[0100]

[0101] Table 3. Test results of durability performance of recycled asphalt concrete

[0102]

[0103] As shown in Tables 1-3, compared to Example 1, Comparative Example 1, which did not modify the lignin-modified hard carbon microspheres, exhibited significantly reduced dynamic stability and freeze-thaw splitting strength ratio, while its G* / sinδ increased significantly after aging. This indicates that the carbon microspheres without silane coupling agent modification have poor compatibility with the asphalt interface, making it difficult to effectively transfer stress and inhibit aging. Comparative Example 3, which did not use lignin-modified hard carbon microspheres, showed significantly reduced performance indicators, indicating that lignin-modified hard carbon microspheres are the core reinforcing phase for constructing a high-stiffness, high-toughness regenerated skeleton. Comparative Example 2, which did not add polyphosphate, showed a much higher G* / sinδ after PAV aging compared to Example 1, and a significantly reduced flexural strain retention rate. This indicates that the lack of polyphosphate led to uncontrolled catalytic oxidation of metal ions, severely impairing long-term durability. Comparative Examples 4 and 5 both showed decreased wear resistance and interfacial stability, demonstrating that hydroxyapatite has unique advantages in improving interfacial anchoring and service durability.

[0104] In summary, the recycled asphalt concrete of the present invention achieves comprehensive performance of high rutting resistance, excellent crack resistance, strong wear resistance, and long service life through the synergistic effect of lignin hard carbon microspheres, high-purity hydroxyapatite, and polyphosphate under high RAP content conditions.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wear-resistant recycled asphalt concrete, characterized in that: The raw materials include the following percentages by weight: 20%–35% recycled asphalt pavement materials, 45%–55% coarse aggregate, 8%–15% fine aggregate, 3%–6% mineral powder, 4.2%–5.8% base asphalt, 0.25%–0.5% recycling agent, 0.3%–1.2% lignin hard carbon microspheres, 0.2%–0.8% hydroxyapatite, and 0.05%–0.3% polyphosphate; The preparation method of the lignin hard carbon microspheres includes the following steps: The lignin suspension was subjected to hydrothermal carbonization, followed by solid-liquid separation and drying to obtain the precursor. The precursor is subjected to high-temperature carbonization treatment to obtain carbides; the temperature of the high-temperature carbonization treatment is 800℃~1200℃. The carbide was impregnated in a silane coupling agent solution for surface modification to obtain lignin hard carbon microspheres.

2. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The concentration of the lignin suspension is 3%wt~8%wt; the reaction conditions for the hydrothermal carbonization treatment are: 180℃~220℃ for 4~12h; the duration of the high-temperature carbonization treatment is 1~3h.

3. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The surface modification temperature is 10~40℃, and the surface modification time is 2~6h.

4. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The silane coupling agent in the silane coupling agent solution is at least one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane, and the concentration of the silane coupling agent solution is 1%wt to 5%wt; the mass-to-volume ratio of the carbide to the silane coupling agent solution is 1g:10~20mL.

5. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The coarse aggregate is one or more of basalt crushed stone, diabase crushed stone, ceramic particles or steel slag; the fine aggregate is manufactured sand; and the mineral powder is at least one of limestone mineral powder or hydrated lime powder.

6. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The regenerator is an aromatic oil, SBS-modified soft asphalt, or a vegetable oil-based regenerator.

7. The wear-resistant recycled asphalt concrete as described in claim 1, characterized in that: The polyphosphate is one or more of sodium tripolyphosphate, sodium hexametaphosphate, potassium polyphosphate, or ammonium polyphosphate.

8. The method for preparing wear-resistant recycled asphalt concrete according to any one of claims 1 to 7, characterized in that: Includes the following steps: A composite functional filler was obtained by mixing lignin hard carbon microspheres, hydroxyapatite, and polyphosphate. The recycled asphalt pavement material, coarse aggregate, and fine aggregate are heated to 145℃~165℃ and dry-mixed for 25~35s; the base asphalt and recycling agent are added and wet-mixed for 60~90s; then the mineral powder and the composite functional filler are added and the mixture is continued for 45~60s to obtain wear-resistant recycled asphalt concrete.

9. The application of the wear-resistant recycled asphalt concrete according to any one of claims 1 to 7, or the wear-resistant recycled asphalt concrete prepared by the preparation method of the wear-resistant recycled asphalt concrete according to claim 8, in the surface layer of urban roads.

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