Preparation method of high-temperature-resistant high-modulus anti-rutting asphalt concrete

Abstract

The application belongs to the technical field of road engineering, and particularly relates to a preparation method of high-temperature-resistant high-modulus anti-rutting asphalt concrete, which comprises the following steps: S1, polyimide fiber pretreatment; S2, basalt fiber pretreatment; S3, preparation of composite modified asphalt; S4, mixing of asphalt mixture; and S5, compaction molding to obtain the high-temperature-resistant high-modulus anti-rutting asphalt concrete. The polyimide fiber and the basalt fiber are pretreated, the composite modified asphalt composed of star-shaped SBS modifier and specific high-modulus agent is prepared, the mineral aggregate, various fibers, anti-stripping agent and the composite modified asphalt are mixed at an optimized ratio, and the accurate compaction process is adopted to construct a multi-component synergistic system, so that the high-temperature resistance, high modulus and anti-rutting capacity of the asphalt concrete are improved.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, and more specifically, relates to a method for preparing high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete. Background Technology

[0002] Existing asphalt concrete is prone to rutting, has insufficient modulus, and poor water stability under high-temperature environments, making it difficult to meet the needs of heavy traffic and roads in high-temperature areas. To address these issues, various improved asphalt concrete preparation methods and related equipment have emerged in recent years, but these technical solutions still have certain limitations in practical applications.

[0003] CN114538829B discloses an SBS-modified asphalt concrete and its preparation method. By adding a specific proportion of SBS modifier and additive particles, the flexibility and crack resistance of the asphalt concrete are improved. Furthermore, placing the additive particles in the center of the mixture achieves rapid mixing, thereby shortening construction time. However, this technical solution primarily focuses on the uniformity of modifier distribution and construction efficiency, failing to effectively address the rutting problem of asphalt concrete under high-temperature conditions. In addition, its modulus improvement under high-temperature environments is limited, making it difficult to meet the high modulus requirements of heavy traffic, and it does not adequately consider water stability optimization, potentially affecting long-term performance.

[0004] CN109704650B discloses a wear-resistant recycled asphalt concrete and its preparation process. By adding components such as steel slag, fiber filler, and wear-resistant filler, the wear resistance and anti-aging ability of asphalt concrete are improved, solving the aging and wear problems caused by temperature changes. However, this technical solution mainly focuses on improving wear resistance and anti-aging performance, and is insufficient in improving rutting resistance and high modulus characteristics under high-temperature conditions. In addition, its preparation process is relatively complex, involving precise proportioning of multiple components and multiple steps, which may increase production costs. Furthermore, it lacks targeted design for optimizing water stability performance under high-temperature environments.

[0005] The above problems indicate that existing asphalt concrete preparation methods still have shortcomings in terms of high-temperature rutting resistance, high modulus characteristics, and water stability optimization. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete. This method involves targeted pretreatment of polyimide fibers and basalt fibers to prepare a composite modified asphalt composed of a star-shaped SBS modifier and a specific high-modulus agent. Aggregates, various fibers, anti-stripping agents, and the composite modified asphalt are mixed in an optimized ratio, and a precise compaction process is employed to construct a multi-component synergistic system, thereby improving the high-temperature resistance, high modulus, and rutting resistance of the asphalt concrete.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 12-18μm and a length of 6-12mm are impregnated in an ethanol aqueous solution containing 3%-5% by mass of silane coupling agent A, stirred and dispersed, and then dried to obtain surface-modified polyimide fibers; the volume ratio of ethanol to water in the ethanol aqueous solution is 9-9.5:1. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 13-17μm and a length of 3-6mm are impregnated in an ethanol aqueous solution of 5%-8% by mass of silane coupling agent B, stirred and dispersed, and then dried to obtain pretreated basalt fibers; the volume ratio of ethanol to water in the ethanol aqueous solution is 9-9.5:1. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155-165℃, add 3-5 parts by weight of star-shaped SBS modifier and 2-4 parts by weight of high modulus agent, disperse and develop to obtain composite modified asphalt; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 170-180℃, add 0.2-0.4 parts by weight of lignin fiber, 0.3-0.6 parts by weight of surface-modified polyimide fiber obtained from S1, 0.2-0.4 parts by weight of pretreated basalt fiber obtained from S2, and 0.5%-2.0% by weight of anti-stripping agent according to the aggregate mixture mass. After dry mixing, add 4.5-6.5 parts by weight of composite modified asphalt obtained from S3, and stir at 165-175℃ and 300-500 rpm until the asphalt uniformly coats the aggregate. S5. After compaction and molding, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained.

[0008] Preferably, in step S1, the specific conditions for stirring, dispersing and drying are: stirring at a constant temperature of 70-80℃ for 1-2 hours, and drying at 160-170℃ for 1.5-2.5 hours; the silane coupling agent A is KH-550.

[0009] Preferably, in step S2, the silane coupling agent B is KH570, and the specific conditions for stirring, dispersing and drying are: stirring at 75-85℃ for 1.5-2.5h and drying at 160-170℃ for 1-2h.

[0010] Preferably, in step S3, the method for preparing the high modulus agent includes the following steps: a) Melt the polyethylene wax by heating it to 155-160℃; b) Add 0.8%-1.2% of the rock pitch mass of titanate coupling agent NDZ-201 and stir at 300-500 rpm for 5 minutes; c) Add rock asphalt powder preheated to 160-165℃, and stir at 165-170℃ and 800-1000rpm for 12-15min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In high modulus agents, the mass ratio of polyethylene wax to rock asphalt powder is 1:1-1.5.

[0011] Preferably, step b) also includes 1.0%-1.5% by mass of ethylene-vinyl acetate copolymer, which is a high modulus agent.

[0012] As a preferred embodiment, the specific process for dispersion development in step S3 is as follows: high-speed shearing speed of 2800-3200 rpm, shearing time of 28-32 min, development temperature of 172-174℃, and development time of 1.8-2.2 h.

[0013] Preferably, in step S4, the dry mixing process is as follows: mixing at 500-600 rpm for 3-5 minutes; each 100 parts by mass of the mineral mixture includes 60-75 parts by mass of diabase coarse aggregate, 20-30 parts by mass of limestone fine aggregate, and the remainder is limestone mineral powder.

[0014] Preferably, in step S4, the anti-stripping agent is an amine anti-stripping agent or quicklime; the amine anti-stripping agent is octadecylamine or polyetheramine.

[0015] Preferably, in step S5, the compaction process is as follows: using a vibratory roller, compacting 2-4 times at 158-168℃ with an amplitude of 0.3-0.5mm for initial compaction; using a vibratory roller or pneumatic tire roller, compacting 4-6 times at 152-162℃ for secondary compaction; and using a steel wheel roller, statically compacting 1-2 times at 148-158℃ for final compaction, with a compaction degree greater than 97%.

[0016] This solution also discloses a method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete as described above, resulting in high-temperature resistant, high-modulus, rutting-resistant asphalt concrete.

[0017] Compared to existing technologies, the advantages of this solution are: 1. From a compositional perspective, polyimide fibers and basalt fibers are modified with a specific silane coupling agent to form a transition layer that improves interfacial compatibility with the asphalt matrix, laying a microscopic foundation for stress transfer. The star-shaped SBS modifier forms an elastic network with its multi-arm structure, working synergistically with the rigid particles of the high-modulus agent to construct a composite structure of elastic support and rigid reinforcement, enhancing the high-temperature anti-flow properties of the asphalt matrix. Lignin fibers reduce segregation through a three-dimensional network structure and form a cross-reinforcing network with the two modified fibers in the gaps of the aggregate skeleton, suppressing high-temperature rutting. The anti-stripping agent strengthens the interfacial bond between asphalt and aggregate through chemical action, avoiding structural loosening caused by water damage. The components form a multi-level synergy from interface modification, matrix strengthening, network reinforcement to water stability improvement. 2. From a process perspective, the fiber pretreatment stage ensures the coupling agent fully reacts and solidifies the modified layer through stirring and drying at specific temperatures and times, avoiding fiber thermal damage while guaranteeing the modification effect. In the preparation of composite modified asphalt, optimized shear speed, temperature, and development time allow star-shaped SBS to fully swell and disperse, forming a stable synergistic structure with the high-modulus agent. Controlling the dry mixing speed and time during mixing balances fiber dispersion uniformity and prevents breakage, while appropriate stirring temperature and speed ensure uniform asphalt coating. The temperature gradient and rolling parameter design in the compaction stage prevent excessive asphalt flow at high temperatures and avoids insufficient compaction at low temperatures, maximizing the synergistic effect of each component and ensuring precise matching of process and component characteristics to achieve performance improvement. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. General Implementation Examples

[0019] A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 12-18μm and a length of 6-12mm are impregnated in an ethanol aqueous solution containing 3%-5% by mass of silane coupling agent A. The mass-volume ratio of fiber to solution is controlled at 1:10-20. After stirring and dispersing, the fibers are dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol aqueous solution is (9-9.5):1. The specific conditions for stirring, dispersing and drying are as follows: stirring at 60-120 rpm and 70-80℃ for 1-2 hours in an electrically heated stirring tank, and then drying at 160-170℃ in an oven with hot air circulation for 1.5-2.5 hours. Silane coupling agent A is KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 13-17μm and a length of 3-6mm are impregnated in an ethanol aqueous solution containing 5%-8% by mass of silane coupling agent B. The mass-volume ratio of fiber to solution is controlled at 1:10-20. After stirring and dispersing, the fibers are dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol aqueous solution is (9-9.5):1. The silane coupling agent B is KH570. The specific conditions for stirring, dispersing and drying are as follows: stirring at 60-120rpm and 75-85℃ for 1.5-2.5h in an electrically heated stirring tank, and drying at 160-170℃ in an oven with hot air circulation for 1-2h. In the fiber pretreatment stage, this scheme uses KH550 (γ-aminopropyltriethoxysilane) to modify polyimide fibers. Because it contains amino and epoxy functional groups, it can form hydrogen bonds or covalent bonds with the carbonyl groups on the surface of polyimide. Basalt fibers are modified using KH570 (γ-methacryloyloxypropyltrimethoxysilane) because it contains unsaturated double bonds, which can form more stable chemical bonds with the silanol groups on the surface of basalt fibers and the active groups in the subsequent asphalt. In an electrically heated mixing tank, the mixture is stirred at 60-120 rpm and 70-80℃ for 1-2 hours to ensure that the coupling agent fully penetrates and reacts with the fiber surface. In an oven with hot air circulation, the mixture is dried at 160-170℃ for 1.5-2.5 hours to remove the solvent and solidify the reaction layer. This method avoids heat damage to the fibers caused by high temperature and ensures the integrity of the surface modification layer, effectively improving the interfacial compatibility between the fibers and the asphalt matrix, and laying a microscopic foundation for stress transfer and reinforcement network construction. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155-165℃, add 3-5 parts by weight of star-shaped SBS modifier and 2-4 parts by weight of high modulus agent, and shear at 2800-3200 rpm for 28-32 minutes at 155-165℃ using a high-speed shear emulsifier. After shearing, transfer to a constant temperature of 172-174℃ for static development for 1.8-2.2 hours to obtain composite modified asphalt; The preparation method of high modulus agent includes the following steps: a) Melt the polyethylene wax by heating it to 155-160℃; b) Add 0.8%-1.2% by weight of the rock pitch titanate coupling agent NDZ-201 and stir at 300-500 rpm for 5 min; in step b), also add 1.0%-1.5% by weight of the high modulus agent ethylene-vinyl acetate copolymer. c) Add rock asphalt powder preheated to 160-165℃, and stir at 165-170℃ and 800-1000rpm for 12-15min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In high modulus agents, the mass ratio of polyethylene wax to rock pitch powder is 1:1-1.5; In composite modified asphalt, the high-modulus agent provides a low-viscosity dispersion medium through the melting of polyethylene wax, reducing the surface energy of rock asphalt particles. Combined with the chemical modification of titanate coupling agent NDZ-201, it enhances the interfacial bonding between rock asphalt and polyethylene wax. Then, ethylene-vinyl acetate copolymer is introduced, utilizing its flexible segments to build connections between rock asphalt, polyethylene wax, and the asphalt matrix, optimizing compatibility and cohesion. The multi-arm structure of the star-shaped SBS modifier fully swells and disperses under high shear rates, precise temperatures, and development times, forming an elastic network. This network, together with the rigid particles of the high-modulus agent, constructs a composite structure of elastic support and rigidity enhancement. The elastic recovery of SBS inhibits high-temperature viscous flow, while the rigidity of the high-modulus agent restricts the thermal motion of molecular chains, thereby improving the modulus and deformation resistance of the asphalt matrix from the microstructure. The high modulus agent constructs an efficient asphalt matrix reinforcement system through the synergistic effect of multiple components and process design: the molten state of polyethylene wax provides a low-viscosity dispersion medium for rock asphalt powder, reduces the surface energy of rock asphalt particles and promotes their uniform dispersion in the molten system; the titanate coupling agent NDZ-201 modifies the surface polarity of rock asphalt powder through chemical bonding, enhances its interfacial compatibility with polyethylene wax and subsequent composite modified asphalt, reduces phase separation and forms a stable bonding interface; the introduction of ethylene-vinyl acetate copolymer utilizes the flexibility and adhesiveness of its molecular chain to build a connection between rock asphalt, polyethylene wax and asphalt matrix, further optimizing the compatibility and cohesion of the composite system. The high-modulus agent, after cooling and granulation, retains this multiphase synergistic structural characteristic. When added to composite modified asphalt, it can utilize its rigid particle characteristics and the natural high-modulus properties of rock asphalt, along with the elastic network formed by star-shaped SBS, to create a composite structure of elastic support and rigid reinforcement in the asphalt matrix. This structure utilizes the elastic recovery ability of SBS to suppress viscous flow at high temperatures, while the rigid particles of the high-modulus agent restrict the thermal motion of molecular chains, thereby improving the overall modulus and high-temperature deformation resistance of the asphalt matrix from a microstructural perspective. This, combined with the aforementioned fiber reinforcement and aggregate skeleton constraint designs, forms a multi-scale synergy, significantly enhancing the high-temperature stability and rutting resistance of asphalt concrete. The amount of ethylene-vinyl acetate copolymer added is pre-designed and calculated using the formula w=x / M, where w is the proportion of ethylene-vinyl acetate copolymer in the total mass of the high-modulus agent, x is the actual amount of ethylene-vinyl acetate copolymer added, and M is the total mass of the high-modulus agent, where M=x+m, and m is the amount of other components, including rock asphalt and polyethylene wax, added. S4. Mixed Asphalt: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 170-180℃, add 0.2-0.4 parts by weight of lignin fiber, 0.3-0.6 parts by weight of surface-modified polyimide fiber obtained from S1, 0.2-0.4 parts by weight of pretreated basalt fiber obtained from S2, and 0.5%-2.0% by weight of anti-stripping agent according to the aggregate mixture mass. After dry mixing, add 4.5-6.5 parts by weight of composite modified asphalt obtained from S3. The mixture is stirred at 165-175℃ and 300-500 rpm until the asphalt evenly coats the aggregate; the dry mixing process is as follows: mixing in an asphalt mixing plant at 500-600 rpm for 3-5 minutes; each 100 parts by weight of the aggregate mixture includes 60-75 parts by weight of diabase coarse aggregate, 20-30 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder; the anti-stripping agent is an amine anti-stripping agent or hydrated lime; the amine anti-stripping agent is octadecylamine or polyetheramine; During the mixing process, the dry mixing stage involves mixing at 500-600 rpm for 3-5 minutes to balance fiber dispersion uniformity with avoiding fiber breakage caused by over-mixing. Combined with the aggregate gradation, the angularity of the diabase coarse aggregate provides an interlocking skeleton, while the remaining limestone fine aggregate fills the voids. Mineral powder enhances asphalt bonding, forming a stable mechanical support structure. Anti-stripping agents such as amines or hydrated lime react chemically, with the polar groups of amines reacting with the hydroxyl groups on the aggregate surface, and the calcium ions of hydrated lime combining with the acidic components of asphalt to strengthen the asphalt-aggregate interface bond and compensate for potential damage to the structure caused by water. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. The compaction process is as follows: using a vibratory roller with an amplitude of 0.3-0.5 mm, initial compaction is carried out 2-4 times at 158-168℃; using a vibratory roller or pneumatic tire roller, secondary compaction is carried out 4-6 times at 152-162℃; and finally, using a steel wheel roller, final compaction is carried out 1-2 times at 148-158℃, with a compaction degree greater than 97%. In the compaction stage, the initial compaction is carried out by vibration compaction before the asphalt has completely cooled to initially position the coarse aggregate. The secondary compaction further improves the density, and the final compaction eliminates wheel tracks. The temperature gradient is set to gradually decrease from the initial compaction to the final compaction, which avoids the excessive flow of asphalt at high temperatures that would lead to a loose structure, and also prevents insufficient compaction at low temperatures that would create voids. This maximizes the synergistic effect of fiber reinforcement, asphalt matrix strengthening, and aggregate skeleton constraint.

[0020] In this invention, polyimide fibers and basalt fibers are surface-modified with a silane coupling agent, forming a transition layer on the fiber surface through chemical bonding or physical adsorption. This effectively improves the interfacial compatibility between the fibers and the asphalt matrix, reduces interfacial defects, and increases stress transfer efficiency, laying a microscopic bonding foundation for subsequent reinforcement. The star-shaped SBS modifier in the composite modified asphalt, with its multi-arm structure, promotes molecular dispersion and swelling in the asphalt, forming an elastic network structure that enhances the asphalt's high-temperature stability and resistance to permanent deformation. Combined with the addition of a high-modulus agent, it strengthens the asphalt through intermolecular interactions or a filling effect. The rigidity of the lignin matrix, combined with the synergistic effect of the two components, endows the asphalt matrix with superior high-temperature anti-flow properties. During mixing, the three-dimensional network structure of lignin fibers adsorbs asphalt and reduces segregation, improving the uniformity of the mixture. Meanwhile, surface-modified polyimide fibers and pretreated basalt fibers, with their high-temperature stability and high modulus characteristics, form a cross-distributed reinforcing network in the gaps between the aggregate skeleton, inhibiting rutting at high temperatures at the microscale. The introduction of anti-stripping agents strengthens the interfacial bond between asphalt and aggregate through chemical action, improves water stability, and avoids structural loosening caused by water damage. From interface modification and asphalt matrix strengthening to multi-fiber synergistic reinforcement and improved interfacial water stability, each step forms a multi-level synergy from micro-bonding to macro-performance, effectively improving the high-temperature stability and rutting resistance of asphalt concrete.

[0021] Unless otherwise specified, the equipment, stirring, dispersion and drying processes involved in Examples 2-5 and all comparative examples are the same as those in Example 1.

[0022] Example 1 A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 15 μm and a length of 9 mm were impregnated in an ethanol-water solution containing 4% (w / w) silane coupling agent A. The mass-to-volume ratio of fibers to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.2:1. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 75°C for 1.5 h in an electrically heated stirring tank, followed by drying at 165°C for 2 h in an oven. The silane coupling agent A was KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 15μm and a length of 4.5mm were impregnated in an ethanol-water solution containing 6.5% by mass of silane coupling agent B. The mass-volume ratio of fiber to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.2:1. The silane coupling agent B was KH570. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100rpm and 80℃ for 2 hours in an electrically heated stirring tank, followed by drying at 165℃ for 1.5 hours in an oven. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 160℃, add 4 parts by weight of star-shaped SBS modifier and 3 parts by weight of high modulus agent, and shear at 3000 rpm for 30 minutes at 160℃ using a high-speed shear emulsifier. After shearing, transfer to 173℃ for constant temperature static development for 2 hours to obtain composite modified asphalt. The preparation method of high modulus agent includes the following steps: a) Melt the polyethylene wax at 157.5°C; b) Add 1.0% by weight of rock pitch titanate coupling agent NDZ-201 and 1.25% by weight of high modulus agent ethylene-vinyl acetate copolymer, and stir at 400 rpm for 5 min; c) Add rock asphalt powder preheated to 162.5℃ and stir at 167.5℃ and 900 rpm for 13.5 min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock pitch powder is 1:1.25; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 175°C, add 0.3 parts by weight of lignin fiber, 0.45 parts by weight of surface-modified polyimide fiber obtained from S1, 0.3 parts by weight of pretreated basalt fiber obtained from S2, and 1.25% by weight of anti-stripping agent. After dry mixing, add 5.5 parts by weight of composite modified asphalt obtained from S3, and stir at 400 rpm at 170°C until the asphalt uniformly coats the aggregate. The dry mixing process is as follows: mix at 550 rpm for 4 minutes in an asphalt mixing plant. Each 100 parts by weight of aggregate mixture includes 67.5 parts by weight of diabase coarse aggregate, 25 parts by weight of limestone fine aggregate, and the remainder is limestone mineral powder; the anti-stripping agent is octadecylamine. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. A vibratory roller is used for initial compaction at 163℃ with an amplitude of 0.4mm, followed by 3 passes at 157℃. Finally, a steel wheel roller is used for 1.5 passes at 153℃, achieving a compaction degree greater than 97%.

[0023] Example 2 A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 12μm and a length of 6mm were impregnated in an ethanol aqueous solution containing 3% (w / w) silane coupling agent A. The mass-to-volume ratio of fibers to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol aqueous solution was 9:1. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 70℃ for 1 hour in an electrically heated stirring tank, followed by drying at 160℃ for 1.5 hours in an oven. The silane coupling agent A was KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 13μm and a length of 3mm were impregnated in an ethanol aqueous solution containing 5% by mass of silane coupling agent B. The mass-volume ratio of fiber to solution was controlled at 1:15 during impregnation. After stirring and dispersing, the fibers were dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol aqueous solution was 9:1. The silane coupling agent B was KH570. The specific conditions for stirring, dispersing and drying were as follows: stirring at 100 rpm and 75℃ for 1.5h in an electrically heated stirring tank, and drying at 160℃ for 1h in an oven. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155℃, add 3 parts by weight of star-shaped SBS modifier and 2 parts by weight of high modulus agent, and shear at 2800 rpm for 28 minutes at 155℃ using a high-speed shear emulsifier. After shearing, transfer to 172℃ for constant temperature static development for 1.8 hours to obtain composite modified asphalt. The preparation method of high modulus agent includes the following steps: a) Melt the polyethylene wax at 155°C; b) Add 0.8% by weight of the rock pitch titanate coupling agent NDZ-201 and 1.0% by weight of the high modulus agent ethylene-vinyl acetate copolymer, and stir at 300 rpm for 5 min; c) Add rock pitch powder preheated to 160°C and stir at 165°C and 800 rpm for 12 minutes; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock pitch powder is 1:1; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 170℃, add 0.2 parts by weight of lignin fiber, 0.3 parts by weight of surface-modified polyimide fiber obtained from S1, 0.2 parts by weight of pretreated basalt fiber obtained from S2, and 0.5% by weight of anti-stripping agent. After dry mixing, add 4.5 parts by weight of composite modified asphalt obtained from S3, and stir at 300 rpm at 165℃ until the asphalt uniformly coats the aggregate. The dry mixing process is: mix at 500 rpm for 3 minutes. Each 100 parts by weight of aggregate mixture includes 60 parts by weight of diabase coarse aggregate, 20 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder; the anti-stripping agent is hydrated lime. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. The compaction process is as follows: initial compaction at 158℃ with an amplitude of 0.3mm twice, secondary compaction at 152℃ four times, and final compaction at 148℃ once, with a compaction degree greater than 97%.

[0024] Example 3 A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 18 μm and a length of 12 mm were impregnated in an ethanol-water solution containing 5% (w / w) silane coupling agent A. The mass-to-volume ratio of fibers to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.5:1. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 80°C for 2 hours in an electrically heated stirring tank, followed by drying at 170°C for 2.5 hours in an oven. The silane coupling agent A was KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 17μm and a length of 6mm were impregnated in an ethanol-water solution containing 8% (w / w) silane coupling agent B. The mass-volume ratio of fiber to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.5:1. The silane coupling agent B was KH570. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 85℃ for 2.5 hours in an electrically heated stirring tank, followed by drying at 170℃ for 2 hours in an oven. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 165℃, add 5 parts by weight of star-shaped SBS modifier and 4 parts by weight of high modulus agent, and shear at 3200 rpm for 32 min at 165℃ using a high-speed shear emulsifier. After shearing, transfer to 174℃ for constant temperature static development for 2.2 h to obtain composite modified asphalt. The preparation method of high modulus agent includes the following steps: a) Melt the polyethylene wax at 160°C; b) Add 1.2% by weight of rock pitch titanate coupling agent NDZ-201 and 1.5% by weight of high modulus agent ethylene-vinyl acetate copolymer, and stir at 500 rpm for 5 min; c) Add rock pitch powder preheated to 165°C and stir at 170°C and 1000 rpm for 15 minutes; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock asphalt powder is 1:1.5; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 180℃, add 0.4 parts by weight of lignin fiber, 0.6 parts by weight of surface-modified polyimide fiber obtained from S1, 0.4 parts by weight of pretreated basalt fiber obtained from S2, and 2.0% by weight of anti-stripping agent. After dry mixing, add 6.5 parts by weight of composite modified asphalt obtained from S3, and stir at 500 rpm at 175℃ until the asphalt uniformly coats the aggregate. The dry mixing process is: mix at 600 rpm for 5 minutes. Each 100 parts by weight of aggregate mixture includes 75 parts by weight of diabase coarse aggregate, 20 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder; the anti-stripping agent is polyetheramine. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. The compaction process is as follows: initial compaction at 168℃ with an amplitude of 0.5mm for 4 times, secondary compaction at 162℃ for 6 times, and final compaction at 158℃ for 2 times, with a compaction degree greater than 97%.

[0025] Example 4 A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 14 μm and a length of 8 mm were impregnated in an ethanol-water solution containing 3.5% (w / w) of silane coupling agent A. The mass-to-volume ratio of fibers to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.1:1. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 72°C for 1.2 h in an electrically heated stirring tank, followed by drying at 162°C for 1.8 h in an oven. The silane coupling agent A was KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 14 μm and a length of 4 mm were impregnated in an ethanol-water solution containing 6% (w / w) silane coupling agent B. The mass-to-volume ratio of fiber to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.1:1. The silane coupling agent B was KH570. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 78°C for 1.8 h in an electrically heated stirring tank, followed by drying at 162°C for 1.2 h in an oven. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 158℃, add 3.5 parts by weight of star-shaped SBS modifier and 2.5 parts by weight of high modulus agent, and shear at 2900 rpm for 29 min at 158℃ using a high-speed shear emulsifier. After shearing, transfer to 172.5℃ for constant temperature static development for 1.9 h to obtain composite modified asphalt; The preparation method of high modulus agent includes the following steps: a) Heat the polyethylene wax to 156°C to melt it; b) Add 0.9% by weight of the rock pitch titanate coupling agent NDZ-201 and 1.1% by weight of the high modulus agent ethylene-vinyl acetate copolymer, and stir at 350 rpm for 5 min. c) Add rock pitch powder preheated to 161°C and stir at 166°C and 850 rpm for 13 min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock asphalt powder is 1:1.25; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 172°C, add 0.25 parts by weight of lignin fiber, 0.4 parts by weight of surface-modified polyimide fiber obtained from S1, 0.25 parts by weight of pretreated basalt fiber obtained from S2, and 1.0% by weight of anti-stripping agent. After dry mixing, add 5.0 parts by weight of composite modified asphalt obtained from S3, and stir at 167°C and 350 rpm until the asphalt uniformly coats the aggregate. The dry mixing process is: mix at 520 rpm for 3.5 minutes. Each 100 parts by weight of aggregate mixture includes 65 parts by weight of diabase coarse aggregate, 22 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder; the anti-stripping agent is octadecylamine. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. The compaction process is as follows: initial compaction at 160℃ with an amplitude of 0.35mm for 2.5 times, secondary compaction at 154℃ for 4.5 times, and final compaction at 150℃ for 1.2 times, with a compaction degree greater than 97%.

[0026] Example 5 A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete includes the following steps: S1. Pretreatment of polyimide fibers: Polyimide fibers with a diameter of 17 μm and a length of 11 mm were impregnated in an ethanol-water solution containing 4.5% (w / w) of silane coupling agent A. The mass-to-volume ratio of fibers to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain surface-modified polyimide fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.4:1. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 78°C for 1.8 h in an electrically heated stirring tank, followed by drying at 168°C for 2.2 h in an oven. The silane coupling agent A was KH550. S2. Basalt fiber pretreatment: Basalt fibers with a diameter of 16μm and a length of 5mm were impregnated in an ethanol-water solution containing 7% (w / w) silane coupling agent B. The mass-to-volume ratio of fiber to solution was controlled at 1:15 during impregnation. After stirring and dispersion, the fibers were dried to obtain pretreated basalt fibers. The volume ratio of ethanol to water in the ethanol-water solution was 9.4:1. The silane coupling agent B was KH570. The specific conditions for stirring, dispersion, and drying were as follows: stirring at 100 rpm and 82℃ for 2.2 hours in an electrically heated stirring tank, followed by drying at 168℃ for 1.8 hours in an oven. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 163℃, add 4.5 parts by weight of star-shaped SBS modifier and 3.5 parts by weight of high modulus agent, and shear at 3100 rpm for 30 min at 163℃ using a high-speed shear emulsifier. After shearing, transfer to 173.5℃ for constant temperature static development for 2.1 h to obtain composite modified asphalt; The preparation method of high modulus agent includes the following steps: a) Heat the polyethylene wax to 159°C until melted; b) Add 1.1% by weight of rock pitch titanate coupling agent NDZ-201 and 1.4% by weight of high modulus agent ethylene-vinyl acetate copolymer, and stir at 450 rpm for 5 min; c) Add rock pitch powder preheated to 164°C and stir at 169°C and 950 rpm for 14 min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock asphalt powder is 1:1.2; S4. Mixing Asphalt Mixture: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 178°C, add 0.35 parts by weight of lignin fiber, 0.55 parts by weight of surface-modified polyimide fiber obtained from S1, 0.35 parts by weight of pretreated basalt fiber obtained from S2, and 1.8% by weight of anti-stripping agent. After dry mixing, add 6.0 parts by weight of composite modified asphalt obtained from S3, and stir at 173°C and 450 rpm until the asphalt uniformly coats the aggregate. The dry mixing process is: mixing at 580 rpm for 4.5 minutes. Each 100 parts by weight of aggregate mixture includes 62 parts by weight of diabase coarse aggregate, 28 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder; the anti-stripping agent is hydrated lime. S5. After compaction, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained. The compaction process is as follows: initial compaction at 166℃ with an amplitude of 0.45mm for 3.5 times, secondary compaction at 160℃ for 5.5 times, and final compaction at 156℃ for 1.8 times, with a compaction degree greater than 97%.

[0027] Comparative Example 1 The difference from Example 1 is that the polyimide fibers were not pretreated.

[0028] Comparative Example 2 The difference from Example 1 is that the basalt was not pretreated.

[0029] Comparative Example 3 The difference from Example 1 lies in the different component ratios during the preparation of the composite modified asphalt: S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155-165℃, add 8 parts by weight of star-shaped SBS modifier and 5 parts by weight of high modulus agent.

[0030] Comparative Example 4 The difference from Example 1 lies in the different component ratios during the preparation of the composite modified asphalt: S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155-165℃, add 2 parts by weight of star-shaped SBS modifier and 1 part by weight of high modulus agent.

[0031] Comparative Example 5 The difference from Example 1 is that the preparation method of the high modulus agent does not include 1.0%-1.5% by mass of ethylene-vinyl acetate copolymer.

[0032] Comparative Example 6 The difference from Example 1 lies in the order of material addition during the preparation of the high modulus agent: The preparation method of high modulus agent includes the following steps: a) Preheat rock asphalt powder to 162.5℃; b) Add 1.0% by weight of rock pitch titanate coupling agent NDZ-201 and 1.25% by weight of high modulus agent ethylene-vinyl acetate copolymer, and stir at 400 rpm for 5 min; c) Add molten polyethylene wax at 157.5℃; stir at 167.5℃ and 900 rpm for 13.5 min; d) Cool to below 120°C and granulate to obtain a high modulus agent.

[0033] Comparative Example 7 The difference from Example 1 is that the high modulus agent preparation ratio is out of range. In the high modulus agent, the mass ratio of polyethylene wax to rock asphalt powder is 1:2.

[0034] Comparative Example 8 The difference from Example 1 is that the high modulus agent preparation ratio is out of range. In the high modulus agent, the mass ratio of polyethylene wax to rock asphalt powder is 1:0.8.

[0035] Comparative Example 9 The difference from Example 1 is that the specific process of dispersion development is as follows: the development temperature is 180°C and the development time is 2.5 hours.

[0036] Comparative Example 10 The difference from Example 1 is that the specific process of dispersion development is as follows: the development temperature is 165°C and the development time is 1.5h.

[0037] Comparative Example 11 The difference from Example 1 is that the asphalt mixture is prepared as follows: based on 100 parts by weight of the aggregate mixture, the aggregate mixture is heated to 175°C, and 0.5 parts by weight of lignin fiber, 0.2 parts by weight of the surface-modified polyimide fiber obtained in S1, 0.5 parts by weight of the pretreated basalt fiber obtained in S2, and 1.5% by weight of anti-stripping agent are added. After dry mixing, 7 parts by weight of the composite modified asphalt obtained in S3 are added, and the mixture is stirred at 400 rpm at 170°C until the asphalt uniformly coats the aggregate. The dry mixing process is: mixing at 550 rpm for 4 minutes. Each 100 parts by weight of the aggregate mixture includes 68 parts by weight of diabase coarse aggregate, 25 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder. The anti-stripping agent is an amine anti-stripping agent, which is octadecylamine or polyetheramine.

[0038] Comparative Example 12 The difference from Example 1 is that the asphalt mixture is prepared as follows: Based on 100 parts by weight of the aggregate mixture, the aggregate mixture is heated to 170-180°C, and 0.1 parts by weight of lignin fiber, 0.7 parts by weight of the surface-modified polyimide fiber obtained in S1, 0.5 parts by weight of the pretreated basalt fiber obtained in S2, and 1.5% by weight of anti-stripping agent are added. After dry mixing, 7 parts by weight of the composite modified asphalt obtained in S3 are added, and the mixture is stirred at 400 rpm at 170°C until the asphalt uniformly coats the aggregate. The dry mixing process is: mixing at 550 rpm for 4 minutes. Each 100 parts by weight of the aggregate mixture includes 68 parts by weight of diabase coarse aggregate, 25 parts by weight of limestone fine aggregate, and the balance being limestone mineral powder. The anti-stripping agent is an amine anti-stripping agent, which is octadecylamine or polyetheramine.

[0039] Test methods: The performance of the examples and comparative examples was tested according to the methods in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering (JTGE20-2011)". The performance test results of the composite modified asphalt are shown in Table 1, and the performance test results of the high temperature resistant, high modulus and rutting resistant asphalt concrete (mixture) are shown in Table 2.

[0040] Table 1. Performance test results of composite modified asphalt in the examples and comparative examples. Example 1 42 88 3200 125 220 Example 2 45 85 2800 110 200 Example 3 40 92 3500 140 240 Example 4 43 86 3000 115 210 Example 5 39 90 3400 135 230 Comparative Example 1 68 65 1800 60 100 Comparative Example 2 65 68 2000 65 110 Comparative Example 3 55 75 2400 85 150 Comparative Example 4 62 70 1900 70 120 Comparative Example 5 58 72 2200 75 130 Comparative Example 6 53 78 2600 95 170 Comparative Example 7 56 73 2100 78 135 Comparative Example 8 59 71 2000 72 125 Comparative Example 9 51 76 2500 90 160 Comparative Example 10 63 69 1700 58 95 Comparative Example 11 57 74 2300 80 140 Comparative Example 12 54 77 2700 92 175 Table 2. Performance test results of high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete (mixture) in the examples and comparative examples. Example 1 9800 2800 4.2 14.5 28 91 87 Example 2 8900 2600 4.5 13.8 30 89 85 Example 3 11200 3100 3.8 15.2 26 94 90 Example 4 9200 2700 4.1 14 27 92 88 Example 5 10500 3000 3.9 14.8 25 93 89 Comparative Example 1 3800 1800 7.5 8.5 45 72 68 Comparative Example 2 4200 2000 7.2 9.2 42 74 70 Comparative Example 3 6500 2300 6 11 35 80 76 Comparative Example 4 4800 1900 6.8 9.8 40 76 72 Comparative Example 5 5500 2100 6.5 10.5 38 78 74 Comparative Example 6 7800 2400 5.5 12 32 84 80 Comparative Example 7 5000 2000 6.2 10 36 79 75 Comparative Example 8 4500 1900 6.6 9.5 39 77 73 Comparative Example 9 7000 2500 5.8 11.5 33 82 78 Comparative Example 10 4000 1700 7 8 43 75 71 Comparative Example 11 6000 2200 5.2 11.2 34 86 82 Comparative Example 12 7200 2400 5 11.8 31 87 83

[0041] This invention addresses the problems of rutting, insufficient modulus, and poor water stability in existing asphalt concrete under high-temperature environments. It proposes a technical solution involving surface modification of polyimide and basalt fibers, composite modification of asphalt with a star-shaped SBS modifier and a specific high-modulus agent, synergistic reinforcement with multiple fibers and anti-stripping agents, and precise compaction. Based on the performance results in Tables 1 and 2, the performance of the examples shows that as the example numbers change from Example 2 to Example 3 and Example 5, the penetration of the composite modified asphalt gradually decreases, while the softening point and dynamic viscosity at 60°C gradually increase. Correspondingly, the dynamic stability and dynamic modulus of the asphalt concrete mixture also show an upward trend, while the porosity decreases, and the residual stability after immersion and freeze-thaw splitting strength ratio increase. This pattern stems from the optimization of the coupling agent concentration and treatment temperature used in the fiber pretreatment in the examples, which resulted in a tighter bond between the fiber and the asphalt matrix interface. The star-shaped SBS modifier and the high modulus agent, when properly proportioned, formed a more complete elastic network and rigid reinforcement structure. The appropriate ratio of polyethylene wax and rock asphalt powder during the preparation of the high modulus agent, as well as the bridging effect of the ethylene-vinyl acetate copolymer, promoted the uniform dispersion of rock asphalt in the asphalt. The reasonable proportion of diabase coarse aggregate in the aggregate gradation constructed a stable interlocking skeleton, while the precise control of compaction temperature and number of passes effectively reduced the porosity and enhanced the overall density.Compared to the examples, Comparative Example 1 suffered from poor interfacial compatibility between the polyimide fibers and asphalt due to the lack of silane coupling agent pretreatment, resulting in hindered stress transfer and significantly reduced high-temperature rutting resistance and modulus. Comparative Example 2, due to insufficient interfacial bonding caused by untreated basalt fibers, had an incomplete fiber reinforcement network and inferior performance compared to the examples. In Comparative Example 3, the dosage of star-shaped SBS modifier and high-modulus agent exceeded the optimized range, leading to uneven dispersion of the modifier in the asphalt and difficulty in forming a stable and uniform elastic network and rigid reinforcement system. In Comparative Example 4, the dosage of both was insufficient, resulting in weak elastic support and rigid reinforcement, and insufficient high-temperature flow resistance of the asphalt matrix. In Comparative Example 5, the absence of ethylene-vinyl acetate copolymer during the preparation of the high-modulus agent resulted in a lack of effective interfacial bridging between the rock asphalt, polyethylene wax, and the asphalt matrix, limiting the reinforcing effect of the high-modulus agent. In Comparative Example 6, the material addition order of the high-modulus agent was altered, resulting in insufficient full utilization of the polyethylene wax. The rock asphalt powder was unevenly distributed within the asphalt. In Comparative Example 7, the mass ratio of polyethylene wax to rock asphalt powder was too high, resulting in excessive rock asphalt powder content and difficulty in dispersion within the system, leading to localized agglomeration. In Comparative Example 8, this ratio was too low, and insufficient rock asphalt powder resulted in weak reinforcing effect of rigid particles. In Comparative Example 9, the development temperature and time of the composite modified asphalt were too high, causing partial thermal oxidative degradation of the star-shaped SBS modifier and destruction of the elastic network structure. In Comparative Example 10, the development temperature and time were too low, preventing the SBS modifier from fully swelling and dispersing, resulting in an incomplete elastic network. In Comparative Example 11, the amount of lignin fiber was too high while the amount of polyimide fiber was too low, leading to an imbalance in the synergistic reinforcing effect between fibers, and the excessive amount of asphalt easily caused segregation of the mixture. In Comparative Example 12, the amount of lignin fiber was insufficient while the amount of polyimide fiber was too high, causing the fibers to easily agglomerate in the mixture and disrupting the uniformity of the reinforcing network. As can be seen, the embodiment achieved multi-level performance improvement from interfacial bonding and asphalt matrix strengthening to multi-fiber network reinforcement and water stability enhancement through the whole-chain synergistic optimization of fiber pretreatment, composite modified asphalt composition, high modulus agent preparation, mixture ratio and compaction process. In contrast, the comparative embodiment deviated from the optimization range in a certain link, resulting in a weakened overall synergistic effect and all performance indicators being lower than those of the embodiment.

Claims

1. A method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete, characterized in that, Includes the following steps: S1. Pretreatment of polyimide fibers: The polyimide fibers are impregnated in an ethanol aqueous solution of 3%-5% by mass of silane coupling agent A, stirred and dispersed, and then dried to obtain surface-modified polyimide fibers. S2. Basalt fiber pretreatment: Basalt fiber is impregnated in an ethanol aqueous solution of 5%-8% by mass of silane coupling agent B, stirred and dispersed, and then dried to obtain pretreated basalt fiber. S3. Preparation of composite modified asphalt: Based on 100 parts by weight of No. 70 road petroleum asphalt, heat to 155-165℃, add 3-5 parts by weight of star-shaped SBS modifier and 2-4 parts by weight of high modulus agent, disperse and develop to obtain composite modified asphalt; S4. Mixing Asphalt: Based on 100 parts by weight of aggregate mixture, heat the aggregate mixture to 170-180℃, add 0.2-0.4 parts by weight of lignin fiber, 0.3-0.6 parts by weight of surface-modified polyimide fiber obtained from S1, 0.2-0.4 parts by weight of pretreated basalt fiber obtained from S2, and 0.5%-2.0% by weight of anti-stripping agent of aggregate mixture. After dry mixing, add 4.5-6.5 parts by weight of composite modified asphalt obtained from S3, and stir at 165-175℃ and 300-500 rpm until the asphalt uniformly coats the aggregate. S5. After compaction and molding, high-temperature resistant, high-modulus, and rutting-resistant asphalt concrete is obtained.

2. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S1, the specific conditions for stirring, dispersing and drying are as follows: stirring at a constant temperature of 70-80℃ for 1-2 hours, and drying at 160-170℃ for 1.5-2.5 hours; silane coupling agent A is KH550.

3. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S2, the specific conditions for stirring, dispersing and drying are: stirring at 75-85℃ for 1.5-2.5h and drying at 160-170℃ for 1-2h; the silane coupling agent B is KH570.

4. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S3, the preparation method of the high modulus agent includes the following steps: a) Melt the polyethylene wax by heating it to 155-160℃; b) Add 0.8%-1.2% of the rock pitch mass of titanate coupling agent NDZ-201 and stir at 300-500 rpm for 5 minutes; c) Add rock asphalt powder preheated to 160-165℃, and stir at 165-170℃ and 800-1000rpm for 12-15min; d) Cool to below 120°C and granulate to obtain a high-modulus agent; In the high modulus agent, the mass ratio of polyethylene wax to rock pitch powder is 1:(1-1.5).

5. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 4, characterized in that: In step b), 1.0%-1.5% of the total mass of high modulus agent ethylene-vinyl acetate copolymer is also added.

6. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: The specific process of dispersion development in step S3 is as follows: high-speed shearing speed is 2800-3200 rpm, shearing time is 28-32 min, development temperature is 172-174℃, and development time is 1.8-2.2 h.

7. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S4, the dry mixing process is as follows: mix at 500-600 rpm for 3-5 minutes; each 100 parts by mass of the mineral mixture includes 60-75 parts by mass of diabase coarse aggregate, 20-30 parts by mass of limestone fine aggregate, and the remainder is limestone mineral powder.

8. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S4, the anti-stripping agent is an amine anti-stripping agent or quicklime; the amine anti-stripping agent is octadecylamine or polyetheramine.

9. The method for preparing high-temperature resistant, high-modulus, rutting-resistant asphalt concrete according to claim 1, characterized in that: In step S5, the compaction process is as follows: using a vibratory roller, compacting 2-4 times at 158-168℃ with an amplitude of 0.3-0.5mm for initial compaction; using a vibratory roller or pneumatic tire roller, compacting 4-6 times at 152-162℃ for secondary compaction; and using a steel wheel roller, statically compacting 1-2 times at 148-158℃ for final compaction, with a compaction degree greater than 97%.

10. A high-temperature resistant, high-modulus, rutting-resistant asphalt concrete prepared by a method according to any one of claims 1-9.