Plant fiber asphalt mixed material as well as preparation method and application thereof

Abstract

The invention provides a plant fiber asphalt mixed material as well as a preparation method and application thereof, and belongs to the technical field of composite asphalt. Performance optimization is achieved through a specific fiber-reinforced asphalt mixture scheme, the asphalt mixture comprises pretreated natural plant fibers, asphalt, coarse materials, fine materials and mineral powder, after mixing, the high-temperature stability, the water damage performance and the fatigue performance of the asphalt can be remarkably improved, the balance of cost and performance is achieved, and the service life of the asphalt is prolonged. And the defect that the cost of the conventional high-performance pavement material is often too high is overcome. The problems of high-temperature stability, water damage performance, fatigue performance, cost and performance balance and the like of a traditional asphalt pavement material are effectively solved, and the comprehensive performance of the pavement material is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite asphalt, and specifically relates to a plant fiber asphalt mixed material and a preparation method and application thereof. Background Art

[0002] With the rapid development of the transportation industry, road pavements are under the influence of increasing traffic flow and heavy-loaded vehicles, and are also facing the influence of complex and changeable climatic conditions. Traditional pavement materials such as ordinary asphalt concrete and cement concrete have gradually exposed some problems during long-term use, such as rutting at high temperatures, cracking at low temperatures, insufficient water stability, and decreased anti-skid performance with time, which makes it difficult to meet the requirements of modern transportation for high performance and long life of pavements. In the existing pavement material improvement technology, it is common to use synthetic fibers (such as polyester fibers, basalt fibers, and wood fibers) to enhance the performance of asphalt concrete pavements. For example, a typical solution is to add 0.3%-0.5% polyester fibers to the asphalt mixture and evenly disperse them in the mixture through mechanical stirring.

[0003] However, the production of synthetic fibers relies on non-renewable resources such as petroleum, and its raw material cost is high. In addition, the production process requires complex chemical processes and large equipment investment, resulting in high market prices for synthetic fibers. For example, the market price of polyester fibers is usually 8,000-12,000 yuan / ton, which significantly increases the cost of pavement construction, especially for large-scale road projects, which is a heavy economic burden; although synthetic fibers can improve the tensile strength of asphalt mixtures to a certain extent, under high temperature conditions, due to the limited interfacial bonding between synthetic fibers and asphalt, it is difficult to effectively limit the flow deformation of asphalt, resulting in the road surface still prone to rutting under high temperature and heavy load conditions. During the high temperature period in summer, the rutting depth of asphalt pavements reinforced with synthetic fibers may reach 5-10mm, which exceeds the allowable rutting depth range (generally not more than 10mm). Synthetic fibers are difficult to degrade in the natural environment, and long-term accumulation will cause potential pollution to the soil and water environment. Moreover, the production process of synthetic fibers consumes a lot of energy and emits greenhouse gases and harmful pollutants, which is not in line with the current concept of environmental protection and sustainable development. Summary of the invention

[0004] Based on the above deficiencies of the prior art, the present invention develops a low-cost, high-performance and environmentally friendly pavement reinforcement material, which significantly improves the high temperature stability, water stability and anti-skid performance of the pavement to meet the strict requirements of modern transportation on road pavements.

[0005] The bamboo fiber referred to in the present invention is cellulose fiber extracted from bamboo, which has the characteristics of high strength, good toughness, and renewability. It is used as a key component to enhance the performance of pavement materials in the present invention. It contains abundant active functional groups such as hydroxyl groups, which enable chemical reactions or physical adsorption when compounded with other materials, thereby enhancing the overall performance of the material. The main chemical components are cellulose, hemicellulose, lignin, pectin, wax, fat, ash powder, etc., among which cellulose, hemicellulose and lignin account for more than 90% of the raw materials. The chemical structure is as follows: Figure 1-3 shown.

[0006] The present invention provides a fiber-reinforced asphalt pavement composite material, specifically comprising: a composite material composed of fibers with specific mass content and specifications (bamboo fiber, 0.3%-0.4% in a low-dosage group, 0.4%-0.5% in a medium-dosage group, 0.5%-0.6% in a high-dosage group, 4-6mm in length, 0.03-0.06mm in diameter), 70# road petroleum asphalt (mass content 4.5%-5.5%), coarse aggregate of specific gradation (4.75-19mm, mass content 40%-45%), fine aggregate (0.075-4.75mm, mass content 35%-40%) and mineral powder (less than 0.075mm, mass content 10%-15%), and replaceable component schemes, such as a scheme of replacing bamboo fiber with hemp fiber and a scheme of replacing part of 70# road petroleum asphalt with SBS modified asphalt.

[0007] The present invention also provides a method for preparing a fiber-reinforced asphalt pavement composite material: a complete process flow covering fiber pretreatment (screening, alkali solution soaking, clean water washing, silane coupling agent modification), determination of the amount of other components (70# asphalt 5%, coarse aggregate 42%, fine aggregate 38%, mineral powder 10%) and mixture preparation (dry mixing of coarse and fine aggregates, stirring with bamboo fiber, stirring with mineral powder, and stirring with asphalt).

[0008] The present invention aims at improving the comprehensive performance of the pavement. The present invention adopts natural plant fiber such as bamboo fiber for reinforcement: according to the physical and chemical properties of bamboo fiber, different dosage groups (low, medium and high) are set to form different degrees of network structure in asphalt mixture, restrain the flow of asphalt, improve flexibility, high temperature stability, water stability, anti-skid performance and fatigue performance, etc. In the low dosage group, the preliminary network structure is used to improve the basic performance; the medium dosage group improves the network structure and fully combines with asphalt, enhances multiple performances and balances cost and performance; the high dosage group constructs a tight and tough network system to withstand heavy loads and high temperatures, but requires strict construction process control.

[0009] Optimize aggregate gradation: Different grading tables are designed according to the different functions of coarse and fine aggregates. Coarse aggregate is used to build a skeleton to bear the load, and fine aggregate is used to fill the gaps to improve density and stability. The combination of the two ensures the stability of the pavement structure, improves the overall performance, and meets the needs of different road projects.

[0010] Regarding the problem of bonding between bamboo fiber and asphalt: Bamboo fiber is treated by immersion in alkali solution: alkali solution (NaOH) is used to react chemically with impurities on the surface of bamboo fiber to decompose and remove impurities, roughen the fiber surface, increase the specific surface area, and facilitate subsequent bonding with asphalt. Different alkali concentrations are used in different dosage groups to ensure the treatment effect and avoid excessive treatment that affects the mechanical properties of bamboo fiber; silane coupling agent modification: silane coupling agent (KH550) is allowed to react with hydroxyl groups on the surface of bamboo fiber to form chemically bonded organic functional groups, enhance the interfacial bonding between bamboo fiber and asphalt, and improve the reinforcing effect of bamboo fiber on asphalt mixture. Similarly, the amount of silane coupling agent is controlled according to different dosage groups to prevent it from accumulating on the fiber surface, affecting the bonding uniformity and increasing costs.

[0011] The present invention aims to solve the deficiencies of asphalt pavement materials in terms of high temperature stability, water loss performance, fatigue performance, etc., and achieves performance optimization through a specific fiber-reinforced asphalt mixture solution:

[0012] 1) Improved high temperature stability:

[0013] Bamboo fiber is added to asphalt mixture in different dosages (0.3%-0.6%), and after pretreatment steps such as screening, alkali solution soaking, water washing and silane coupling agent modification, it is mixed with asphalt, coarse and fine aggregates and mineral powder in a specific proportion to prepare a pavement composite material. Bamboo fiber is mainly composed of cellulose, hemicellulose and lignin, and has high thermal stability. Under high temperature environment, it can maintain good structural integrity, and the network structure formed can restrain the flow of asphalt and limit the deformation of the mixture. From the test results, as the bamboo fiber dosage increases from 0.3% to 0.6%, the rutting depth decreases from 4.86mm to 3.05mm. Compared with the reference group with 4% polyester fiber, the rutting depth is significantly reduced, which proves that bamboo fiber effectively improves the high temperature stability of the material and solves the problem of easy deformation of traditional pavement materials at high temperatures.

[0014] 2) Enhanced water damage performance:

[0015] By controlling the dosage of bamboo fiber within a suitable range (such as medium and high dosages of 0.4%-0.6%), a three-dimensional network structure is formed in the mixture, and specific pretreatment and mixture preparation processes are adopted. The network structure formed by medium and high dosage bamboo fiber can effectively prevent water intrusion and reduce the damage of water to the internal structure of the material, thereby maintaining a high water-immersion Marshall stability; in the freeze-thaw cycle, bamboo fiber, with its own flexibility and tensile strength, synergizes with the matrix material to alleviate the internal stress caused by temperature changes, inhibit the generation and expansion of microcracks, and improve the freeze-thaw splitting strength ratio. The test data show that the water-immersion Marshall stability and freeze-thaw splitting strength ratio of each bamboo fiber dosage group are equivalent to or even better than those of the reference group at medium and high dosages, solving the problem of reduced durability of pavement materials due to water damage.

[0016] 3) Improved fatigue performance:

[0017] Select the appropriate bamboo fiber dosage (medium to high dosage 0.4%-0.6%), and ensure that it is evenly distributed in the mixture and has a good interface bonding with the matrix. Bamboo fibers with medium to high dosages build a dense network in the material, which acts like a buffer zone to prevent the generation and expansion of fatigue cracks. Its fibrous morphology can bridge microcracks and inhibit their development; at the same time, the good interface bonding between bamboo fibers and the matrix ensures effective stress transmission and synergistic resistance to fatigue damage. Tests show that the fatigue performance of bamboo fibers at medium to high dosages is significantly better than that of the reference group, and the fatigue life is significantly improved, which effectively solves the problem of fatigue damage to the pavement under long-term repeated loads.

[0018] 4) Balance optimization between cost and performance:

[0019] Different bamboo fiber dosage groups of low, medium and high are set up, and replaceable component solutions are provided, such as hemp fiber replacing bamboo fiber, SBS modified asphalt partially replacing 70# road petroleum asphalt, etc., and the specific dosage and preparation process of each component are clarified. The low-dosage bamboo fiber group (0.3%-0.4%) can optimize the basic performance of pavement materials without significantly increasing costs, and is suitable for general road projects; the medium-dosage group (0.4%-0.5%) achieves a good balance between performance and cost, and is suitable for most roads with medium traffic flow and environmental conditions; the high-dosage group (0.5%-0.6%) is suitable for occasions with extremely high requirements for pavement performance. Through this gradient dosage design and replaceable solutions, it can be flexibly selected according to different project needs to achieve an optimized balance between cost and performance, overcoming the disadvantage that high-performance pavement materials are often too expensive in the past.

[0020] In summary, the present invention effectively solves the problems of traditional asphalt pavement materials in high temperature stability, water loss performance, fatigue performance, and cost-performance balance through reasonable arrangement and optimization of the component design, pretreatment method, preparation process, and performance test of bamboo fiber reinforced asphalt mixture, thereby achieving a significant improvement in the comprehensive performance of pavement materials.

[0021] The present invention can be replaced by other solutions in terms of raw materials and bamboo fiber pretreatment methods, as follows:

[0022] 1) Alternative pretreatment methods for bamboo fibers: Bioenzyme treatment can be used instead of alkali soaking and silane coupling agent modification, using specific cellulases and hemicellulases to decompose impurities on the surface of bamboo fibers and generate some active groups on the fiber surface to promote the combination with asphalt. However, the conditions of bioenzyme treatment (such as temperature, pH value, enzyme dosage and treatment time) need to be precisely controlled to ensure the stability and consistency of the treatment effect.

[0023] 2) Reinforcement material substitution: In addition to bamboo fiber, other natural plant fibers (such as hemp fiber, coconut shell fiber, etc.) can also be explored for similar pretreatment and application. However, the pretreatment process and pavement material formula need to be adjusted accordingly according to the characteristics of different fibers (such as fiber length, strength, chemical composition, etc.) to achieve a reinforcement effect similar to or better than bamboo fiber.

[0024] 3) Aggregate replacement: In terms of aggregate, it is possible to consider using some recycled aggregates (such as waste concrete aggregates, old road milling materials, etc.) to replace natural aggregates. However, the performance of recycled aggregates varies greatly, and strict screening and pretreatment (such as crushing, screening, cleaning, strengthening, etc.) are required. The mix ratio of the mixture must be redesigned and optimized to ensure that the performance of the pavement material is not significantly affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the chemical structure of cellulose;

[0026] Figure 2 is the chemical structure of cellulose;

[0027] Figure 3 The three basic structures of lignin, from left to right, are guaiacylpropane, syringylpropane and p-hydroxyphenylpropane;

[0028] Figure 4 This is the macroscopic morphology of bamboo fiber. DETAILED DESCRIPTION

[0029] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0030] Example 1

[0031] 1) Composition (components and content)

[0032] Bamboo fiber: The mass content is set at three gradients, namely 0.3%-0.4% (low dosage group), 0.4%-0.5% (medium dosage group), and 0.5%-0.6% (high dosage group). The bamboo fiber length is 4-6mm and the diameter is 0.03-0.06mm. The macroscopic morphology is shown in the figure. Figure 4 The main chemical components are shown in Table 1.

[0033] Table 1 Coarse aggregate gradation table

[0034]

[0035] Asphalt: Use 70# road petroleum asphalt, with a mass content of 4.5%-5.5%;

[0036] Aggregate: Coarse aggregate (4.75-19mm) mass content 40%-45%; fine aggregate (0.075-4.75mm) mass content 35%-40%; mineral powder (less than 0.075mm) mass content 10%-15%. See Table 2 and Table 3 for gradation tables.

[0037] Table 2 Coarse aggregate gradation table

[0038]

[0039] Table 3 Fine aggregate gradation table

[0040]

[0041] The grading tables are separated because of different particle sizes and uses. Coarse aggregate (4.75-19mm) is mainly used to build the skeleton structure of the pavement material to withstand pressure such as vehicle loads. Its particles are larger and interlock with each other in the mixture to provide stability. Fine aggregate (0.075-4.75mm) is mainly used to fill the gaps between coarse aggregates, making the pavement material structure more compact and improving the overall stability and durability. Separate grading tables can better design and control the distribution of each particle according to their different functional characteristics to achieve an ideal pavement structure combination.

[0042] Secondly, it is convenient to accurately control the quality.

[0043] 2) Preparation method

[0044] (1) Bamboo fiber pretreatment:

[0045] ① Screening: Remove impurities, short fibers and fibers that do not meet the length and diameter requirements from the bamboo fibers through mechanical screening, and retain fibers with a length of 4-6mm and a diameter of 0.03-0.06mm;

[0046] ②Alkali solution soaking: soak the screened bamboo fiber in 3%-5% NaOH solution (the concentration of the low-dosage group is 3%; the medium-dosage group is 4%; the high-dosage group is 5%), soak for 3 hours at room temperature to decompose and remove impurities on the fiber surface, roughen the fiber surface, increase the specific surface area, and facilitate subsequent modification and combination with asphalt;

[0047] ③ Rinse with clean water: rinse the soaked bamboo fiber with plenty of clean water until it becomes neutral, remove the residual alkali solution, and prevent the alkali solution from having adverse effects on the subsequent material performance;

[0048] ④ Silane coupling agent modification: The washed bamboo fiber is mixed with silane coupling agent KH550 (the dosage is 2%-4% of the mass of the bamboo fiber, 2% for the low dosage group; 3% for the medium dosage group; and 4% for the high dosage group) at 100°C for 2 hours to allow the silane coupling agent molecules to chemically react with the hydroxyl groups on the surface of the bamboo fiber to form chemically bonded organic functional groups on the fiber surface, thereby enhancing the interfacial bonding force between the bamboo fiber and asphalt, thereby improving the reinforcing effect of the bamboo fiber on the asphalt mixture.

[0049] (2) Dosage of other compositions:

[0050] The dosage of 70# asphalt is 5%; the dosage of coarse aggregate is 42%; the dosage of fine aggregate is 38%; the dosage of mineral powder is 10%; the dosage of bamboo fiber is 0.5% and the dosage of additive (warm mix agent) is 4.5%.

[0051] (3) Mixture preparation:

[0052] ① Add coarse aggregate and fine aggregate into the mixer and dry mix for 3 minutes to make the coarse and fine aggregates preliminarily mixed;

[0053] ② Sprinkle the pretreated bamboo fiber evenly into the aggregate being stirred, and continue stirring for 4 minutes to disperse the bamboo fiber in the aggregate and avoid fiber agglomeration;

[0054] ③ Add the mineral powder into the mixer and stir it with the aggregate and bamboo fiber for 1 minute to ensure that the mineral powder is fully in contact with the aggregate and bamboo fiber;

[0055] ④ Slowly pour the asphalt heated to 160°C into the mixer and continue stirring for 30 minutes to ensure that the asphalt can be evenly coated on the surface of aggregate, bamboo fiber and mineral powder to form a stable bamboo fiber reinforced asphalt pavement composite material.

[0056] (3) Performance testing and inspection

[0057] In order to detect the effect of bamboo fiber on the performance of asphalt mixture, this invention uses asphalt mixture with 4% polyester fiber as a reference for analysis.

[0058] ①Test method

[0059] High temperature stability: The test method is a standard rutting tester, which simulates the effect of vehicle driving on the road surface and measures the deformation depth of the road surface before and after the test. The test temperature is set at 60°C and the loading number is 10,000 times.

[0060] Water damage performance: The test method is the immersion Marshall test. After the specimen is immersed in a 60°C water bath for 48 hours, its stability is measured using a Marshall stability instrument; freeze-thaw splitting test, after the specimen is subjected to 15 freeze-thaw cycles, the freeze-thaw splitting strength ratio is calculated by testing the splitting strength.

[0061] Fatigue performance: Use a fatigue testing machine to apply repeated loads to the specimen, and record the number of load cycles when the specimen reaches failure, that is, the fatigue life.

[0062] ②Test results

[0063] Table 4 Performance test results

[0064]

[0065]

[0066] As shown in Table 4, the rutting depth shows an overall downward trend as the bamboo fiber content increases from 0.3% to 0.6%. When the bamboo fiber content is 0.3%, the rutting depth is 4.86mm, which is 11.96% lower than the reference group. This is because bamboo fiber itself has high thermal stability. Bamboo fiber is mainly composed of cellulose, hemicellulose and lignin, which enable it to maintain good structural integrity under high temperature environment. In contrast, the chemical structure of polyester fiber may be more likely to change at high temperature. For example, when polyester fiber approaches its glass transition temperature, the molecular chain segments begin to move, resulting in a decrease in the physical properties of the fiber, while this property change of bamboo fiber is relatively small. When the bamboo fiber content increases to 0.6%, the rutting depth drops to 2.97mm. This shows that the incorporation of bamboo fiber helps to improve the material's anti-rutting ability, reducing the deformation caused by vehicle load.

[0067] Compared with the reference group, the water-immersion Marshall stability and freeze-thaw splitting strength ratio of bamboo fiber in each dosage group are equivalent to or even better at medium and high dosages. This is due to many reasons. At medium and high dosages, bamboo fiber forms a relatively complete three-dimensional network structure in the material, which can not only effectively prevent water intrusion and reduce the damage of water to the internal structure of the material, but also maintain the water-immersion Marshall stability at a high level. Moreover, in the freeze-thaw cycle, bamboo fiber, with its good flexibility and tensile strength, synergizes with the matrix material to alleviate the internal stress caused by temperature changes, inhibit the generation and expansion of microcracks, and ultimately improve the freeze-thaw splitting strength ratio, thereby showing better durability and stability performance than the reference. However, the bamboo fiber dosage within a certain range of 0.30%-0.50% will increase the water-immersion Marshall stability and freeze-thaw splitting strength ratio, and it will decrease after exceeding 0.50%.

[0068] The fatigue performance of bamboo fiber at medium and high dosages is significantly better than the 45,000 times of the reference group, mainly due to its unique fiber reinforcement mechanism, good interface bonding characteristics and its own material properties. The bamboo fiber at medium and high dosages builds a dense network in the material, which effectively prevents the generation and expansion of fatigue cracks like a buffer zone. Its fibrous morphology can bridge microcracks and inhibit their development. At the same time, the good interface bonding between bamboo fiber and the matrix ensures effective stress transmission and synergistically resists fatigue damage. Its own suitable mechanical properties and uniform and dense distribution state enable it to resist fatigue damage from multiple directions and positions. Under the combined effect, it shows an anti-fatigue advantage far exceeding the reference.

[0069] It can also be seen from Table 4 that the test results of the same bamboo fiber dosage of 0.40% and 0.50% in different dosage groups are different, which is due to the different alkali concentrations and silane coupling agent dosages during bamboo fiber pretreatment. The alkali concentration of the low dosage group is 3%, and the silane coupling agent dosage is 2%, which has limited removal of impurities on the bamboo fiber surface and introduction of active groups; while in the medium dosage group, the alkali concentration is 4%, the silane coupling agent dosage is 3%, and the high dosage group, the alkali concentration is 5%, and the silane coupling agent dosage is 4%. The higher treatment concentration and dosage make the bamboo fiber surface rougher and more active groups, which significantly affects the bonding ability of bamboo fiber and asphalt, and ultimately causes different test results. However, the higher the alkali concentration and the dosage of silane coupling agent, the better. Too high alkali concentration will excessively corrode bamboo fiber, weaken its mechanical properties, destroy the fiber structure, and make it difficult to effectively play a reinforcing role in the mixture; too much silane coupling agent will accumulate on the surface of bamboo fiber, affecting the uniformity of bonding with asphalt, while increasing costs and potential environmental risks. Therefore, in the pretreatment of bamboo fiber, it is necessary to reasonably control the concentration of alkali solution and the amount of silane coupling agent to balance their effects on the performance of bamboo fiber and its bonding ability with asphalt, achieve the best comprehensive effect, and ensure the performance of asphalt mixture.

[0070] Taking all factors into consideration, a bamboo fiber dosage of 0.50% is a better choice. Because although 0.60% performs better in terms of rutting depth, the water-immersed Marshall stability and freeze-thaw splitting strength ratio are in a better balance at 0.50%, and there is not much disadvantage compared to the situation at 0.60%. At the same time, the fatigue performance is already at a high level at 0.50%. Compared with other lower dosages, all aspects of performance are superior at 0.50%. Therefore, from the perspective of overall performance balance, the optimal bamboo fiber dosage is 0.50%. Compared with the reference, its rutting depth is reduced by 40.22%; the water-immersed Marshall stability, freeze-thaw splitting strength ratio and fatigue performance are increased by 13.78%, 9.17% and 51.11% respectively.

[0071] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A plant fiber asphalt mixed material, characterized in that: including natural plant fibers, asphalt and aggregates; The aggregate includes coarse aggregate, fine aggregate and mineral powder; The natural plant fibers are pretreated to form organic functional groups chemically bonded with asphalt on the fiber surfaces.

2. The plant fiber asphalt mixed material according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 0.3-0.6 parts of natural plant fiber, 4.5-5.5 parts of asphalt, 40-45 parts of coarse aggregate, 35-40 parts of fine aggregate and 10-15 parts of mineral powder.

3. The plant fiber asphalt mixed material according to claim 1 or 2, characterized in that: The sources of the natural plant fibers include bamboo fibers, hemp fibers or coconut shell fibers.

4. The plant fiber asphalt mixed material according to claim 3, characterized in that: The bamboo fiber pretreatment method comprises soaking the bamboo fiber in an alkaline solution to remove impurities on the fiber surface, washing the bamboo fiber with clean water until it is neutral, and modifying the bamboo fiber with a silane coupling agent.

5. The plant fiber asphalt mixed material according to claim 4, characterized in that: The bamboo fiber has a length of 4 to 6 mm and a diameter of 0.03 to 0.06 mm.

6. The plant fiber asphalt mixed material according to claim 4, characterized in that: The alkaline solution includes 3%-5% NaOH solution, and the soaking time is 3 hours.

7. The plant fiber asphalt mixed material according to claim 4, characterized in that: The silane coupling agent includes KH550, the usage amount is 2% to 4% of the mass of the bamboo fiber, and the modification treatment takes 2 hours.

8. The method for preparing the plant fiber asphalt mixed material according to any one of claims 1 to 7, characterized in that: The following steps are involved: ① Evenly mix the coarse aggregate and the fine aggregate to obtain the first mixture; ② Evenly sprinkle the pretreated fibers into the first mixture to obtain a second mixture; ③ Add the mineral powder to the second mixture to obtain the third mixture; ④ Slowly pour the asphalt heated to 160°C into the third mixture to form a stable fiber-reinforced asphalt pavement composite material.

9. The preparation method according to claim 8, characterized in that: The asphalt includes 70# road petroleum asphalt or a mixed asphalt containing SBS modified asphalt and 70# road petroleum asphalt.

10. The preparation method according to claim 9, characterized in that: The SBS modified asphalt content is 20% to 30% of the total asphalt mass.

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