Environment-friendly steel slag asphalt mixture and preparation method thereof

Abstract

The invention belongs to the technical field of asphalt mixtures, and particularly relates to an environment-friendly steel slag asphalt mixture and a preparation method thereof. The environment-friendly steel slag asphalt mixture is prepared from the following raw materials in parts by weight: 5-10 parts of SBS modified asphalt, 50-60 parts of steel slag, 10-15 parts of fine aggregate, 5-10 parts of mineral powder, 5-10 parts of a steel slag stabilizer and 0.5-1 part of a reinforcing agent. According to the environment-friendly steel slag asphalt mixture, the reinforcing agent and the steel slag stabilizer are introduced and act together, so that the asphalt mixture has excellent water stability, high-temperature rutting resistance, low-temperature crack resistance, deformation resistance and fatigue resistance, the long-term service durability of a pavement can be effectively guaranteed, and the service life of the pavement is prolonged; and moreover, resource utilization of solid waste is realized, and the method is suitable for various road asphalt pavement projects.

Description

Technical Field

[0001] This invention belongs to the field of asphalt mixture technology, specifically relating to an environmentally friendly steel slag asphalt mixture and its preparation method. Background Technology

[0002] With the rapid development of road construction in my country, the demand for asphalt mixtures, as a core material for road surfaces, continues to rise. At the same time, the steel industry generates a large amount of steel slag solid waste, whose stockpiling occupies land and pollutes the water and soil environment. Resource utilization has become an important direction for the industry's green development. Steel slag possesses excellent properties such as high hardness, high wear resistance, and high compressive strength. As an aggregate for asphalt mixtures, it can replace some natural stone, achieving both industrial solid waste disposal and reducing road surface material costs, thus possessing significant economic and environmental value.

[0003] However, the use of steel slag in asphalt pavement still faces two major technical bottlenecks that severely limit its large-scale engineering application: First, steel slag contains free calcium oxide and free magnesium oxide, which continuously hydrate upon contact with water, causing volume expansion and easily leading to blistering, cracking, and loosening of the asphalt mixture in later stages, significantly shortening the pavement's service life. Second, the porous and hydrophilic surface of steel slag results in low wettability and adhesion strength with asphalt. Under the combined effects of traffic loads and a water environment, the asphalt film is prone to peeling, and the mixture is susceptible to water damage, dispersion, fatigue cracking, and other defects.

[0004] Existing technologies employ basalt fibers and stabilizers to improve the overall performance of asphalt mixtures. However, ordinary basalt fibers have a highly inert surface and weak interfacial bonding with asphalt, making them prone to interfacial slippage and debonding, thus limiting their reinforcing effect. Conventional steel slag modifiers can only simply fill pores, exhibiting poor water-blocking stability and short-lasting swelling suppression effects, leading to cracking and bulging in the later stages. Furthermore, the mixtures struggle to simultaneously meet the comprehensive requirements of high-temperature rutting resistance, low-temperature crack resistance, water damage resistance, fatigue resistance, and long-term volume stability.

[0005] Therefore, developing an environmentally friendly steel slag asphalt mixture that can simultaneously achieve steel slag stabilization, strong fiber-asphalt interface bonding, and significantly improve the overall road performance of the mixture, in order to resolve the contradiction between solid waste resource utilization and pavement durability, has become an urgent technical problem to be solved in the fields of road engineering and new materials. Summary of the Invention

[0006] The primary objective of this invention is to provide an environmentally friendly steel slag asphalt mixture. This asphalt mixture possesses excellent low-temperature crack resistance, fatigue resistance, and high-temperature stability, meeting the requirements for rutting resistance; furthermore, it improves the interfacial adhesion and compatibility between steel slag and asphalt, ensuring mixture stability and extending pavement service life.

[0007] The second objective of this invention is to provide a method for preparing an environmentally friendly steel slag asphalt mixture. This invention features a simple and convenient preparation process, requires no complex equipment, has a reasonable raw material ratio, is highly operable, facilitates industrial-scale promotion, and is applicable to various types of highway asphalt pavement projects.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An environmentally friendly steel slag asphalt mixture is composed of the following raw materials in parts by weight: 5-10 parts SBS modified asphalt, 50-60 parts steel slag, 10-15 parts fine aggregate, 5-10 parts mineral powder, 5-10 parts steel slag stabilizer, and 0.5-1 parts reinforcing agent. The preparation process of the reinforcing agent is as follows: (1) Basalt fibers were washed, soaked in an acidic solution, and then removed to obtain pretreated basalt fibers; (2) The basalt fibers pretreated in step (1) are added to a mixed solution of ethanol and water containing silane coupling agent, allowed to stand, and dried to obtain silane coupling agent modified basalt fibers. (3) Mix 2-methyl-4-penten-2-ol and itaconic acid, heat and stir, then add basalt fiber modified with silane coupling agent, DMF and AIBN, and continue heating to obtain the reinforcing agent.

[0009] Further, in step (1), the ratio of the amount of basalt fiber to the acidic solution is 1g:8-10mL; the acidic solution is a hydrochloric acid solution with a concentration of 0.1-0.3mol / L.

[0010] Further, in step (2), the ratio of the pretreated basalt fiber to the mixed solution is 1g:15-20mL; the concentration of the silane coupling agent in the mixed solution of ethanol and water containing the silane coupling agent is 2-3wt%, the silane coupling agent is vinyltriethoxysilane, and the volume ratio of ethanol to water is 16:1.

[0011] Further, in step (3), the mass ratio of the basalt fiber modified with 2-methyl-4-penten-2-ol, itaconic acid, silane coupling agent, DMF and AIBN is 1:(2.5-3):(1-1.3):10:(0.01-0.015).

[0012] Further, the soaking time in step (1) is 30-40 min; the standing time in step (2) is 20-30 min; the heating and stirring temperature in step (3) is 60-70℃ and the time is 1-2 h; the continued heating reaction time is 3-5 h.

[0013] Further, the preparation process of the steel slag stabilizer is as follows: Tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate are added to a mixed solvent of ethanol and water, stirred and mixed evenly, and then allowed to stand at room temperature for 5-8 hours. After centrifugation, freeze drying, and calcination, microspheres are obtained. The microspheres are added to an acetic acid solution of chitosan, and then calcium chloride is added. The mixture is stirred at 40-50°C for 3-5 hours to obtain the steel slag stabilizer.

[0014] Further, the ratio of tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate is 6.25 mL: 2.36-3.2 g: 1.5-2.5 g: 1.5-2 mL; the ratio of tetraethoxysilane to the mixed solvent is 1 g: 15 mL; the volume ratio of ethanol to water in the mixed solvent is 10:3; and the calcination temperature is 600-650℃, and the time is 1-3 h.

[0015] Furthermore, the mass ratio of the microspheres to the acetic acid solution of chitosan is 1:10, the amount of calcium chloride added is 3 wt% of the acetic acid solution of chitosan; the concentration of chitosan in the acetic acid solution of chitosan is 2-3 wt%; and the volume concentration of the acetic acid solution is 2%.

[0016] Furthermore, the SBS modified asphalt is type I-B; the steel slag contains ≤3% calcium oxide, 3-10% magnesium oxide, 1-3% manganese oxide, ≤2% iron, and has a particle size of 5-10mm; the fine aggregate is manufactured limestone sand with a particle size of 0.1-3mm; and the mineral powder is limestone mineral powder with a particle size of 40-75μm.

[0017] A method for preparing an environmentally friendly steel slag asphalt mixture includes the following steps: According to the specified proportions, SBS modified asphalt, steel slag, fine aggregate, mineral powder, steel slag stabilizer, and reinforcing agent are mixed evenly to obtain the final product.

[0018] Compared with the prior art, the main advantages of the present invention are as follows: 1. The reinforcing agent of this invention uses basalt fibers that have been acid-washed and activated to remove impurities from the surface, increasing the number of surface hydroxyl groups. Then, it is modified with vinyltriethoxysilane to introduce double bonds onto the basalt fiber surface, improving the surface activity and interfacial bonding ability of the basalt fibers. 2-Methyl-4-penten-2-ol and itaconic acid undergo a pre-reaction under heating conditions to form an active intermediate containing unsaturated double bonds and polar functional groups. Under the action of the initiator AIBN, this intermediate undergoes free radical graft copolymerization with vinyl groups on the basalt fiber surface, forming a uniform and stable organic graft layer on the basalt fiber surface.

[0019] This organic layer can form physical entanglement and interfacial bonding with the macromolecular chains of asphalt, significantly improving the wettability, compatibility, and bond strength between basalt fibers and asphalt. This ensures that the basalt fibers are evenly dispersed and stably stressed within the asphalt matrix, reducing the likelihood of interfacial debonding and slippage. The organic grafting layer also imparts a certain degree of toughness and deformability to the basalt fibers, buffering temperature stress and vehicle fatigue stress, delaying crack propagation, and improving the low-temperature crack resistance and fatigue resistance of the mixture. The modified basalt fibers form a three-dimensional network support structure within the mixture, effectively dispersing stress, inhibiting deformation, and significantly improving the high-temperature stability of the mixture, meeting the requirements for rutting resistance.

[0020] 2. The core of the steel slag stabilizer of the present invention is a porous calcium-silicon-based microsphere. Its main component is CaO-SiO2, which is highly matched with the mineral composition of steel slag. It can efficiently fill the loose pores on the surface of steel slag, block water intrusion, reduce the water absorption rate of steel slag, and effectively inhibit the volume expansion caused by the hydration of free calcium oxide and free magnesium oxide in steel slag, so as to avoid problems such as bulging and cracking of the mixture in the later stage and ensure the stability of the mixture.

[0021] The outer layer of the steel slag stabilizer of this invention is a chitosan coating layer modified by calcium chloride crosslinking. The chitosan molecules are rich in active functional groups such as amino and hydroxyl groups. On the one hand, it can form high-strength hydrogen bonds and electrostatic adsorption with the surface of steel slag, realizing the tight combination of stabilizer and steel slag aggregate. On the other hand, its organic long-chain structure can fully entangle with asphalt molecules, improve the interfacial bonding strength between steel slag and asphalt, improve the compatibility between steel slag and asphalt, and extend the service life of the pavement.

[0022] 3. This invention provides a method for preparing an environmentally friendly steel slag asphalt mixture. The preparation process is simple and convenient, requiring no complex production equipment or cumbersome preparation steps. It is highly operable and easy to promote industrially. Attached Figure Description

[0023] Figure 1 This is an electron microscope image of the reinforcing agent obtained in Example 1 of the present invention; Figure 2 This is an electron microscope image of the steel slag stabilizer obtained in Example 1 of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products obtained through commercial channels.

[0025] The SBS modified asphalt of this invention is of type I-B; the steel slag contains ≤3% calcium oxide, 3-10% magnesium oxide, 1-3% manganese oxide, ≤2% iron, and has a particle size of 5-10mm; the fine aggregate is 0.1-3mm limestone manufactured sand; and the mineral powder is limestone mineral powder with a particle size of 40-75μm.

[0026] Example 1 An environmentally friendly steel slag asphalt mixture is composed of the following raw materials in parts by weight: 8 parts SBS modified asphalt, 55 parts steel slag, 12 parts fine aggregate, 8 parts mineral powder, 8 parts steel slag stabilizer, and 0.9 parts reinforcing agent. The preparation process of the reinforcing agent is as follows: (1) After cleaning the basalt fiber, soak it in 0.2 mol / L hydrochloric acid solution for 35 min and then take it out. The ratio of basalt fiber to hydrochloric acid solution is 1 g: 9 mL. Wash it with deionized water until the basalt fiber is neutral and dry it to obtain pretreated basalt fiber. (2) Add silane coupling agent (vinyltriethoxysilane) to a mixed solution of ethanol and water (volume ratio of ethanol to water is 16:1), wherein the concentration of silane coupling agent in the mixed solution is 2.5wt%; add the basalt fiber pretreated in step (1) to a mixed solution of ethanol and water containing vinyltriethoxysilane, wherein the volume ratio of the pretreated basalt fiber to the mixed solution is 1g:18mL; let stand for 25min, and dry to obtain silane coupling agent modified basalt fiber; (3) Mix 2-methyl-4-penten-2-ol and itaconic acid, then heat and stir at 65°C for 1.5 h. Add basalt fiber modified with silane coupling agent, DMF (N,N-dimethylformamide), and AIBN (azobisisobutyronitrile), wherein the mass ratio of 2-methyl-4-penten-2-ol, itaconic acid, basalt fiber modified with silane coupling agent, DMF, and AIBN is 1:2.8:1.2:10:0.012. Continue heating and reacting for 4 h. After the reaction is complete, filter, wash, and dry to obtain the reinforcing agent. The electron micrograph of the reinforcing agent is shown below. Figure 1 As shown.

[0027] The preparation process of the steel slag stabilizer is as follows: Tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate are added to a mixed solvent of ethanol and water (volume ratio of ethanol to water is 10:3). The volume ratio of tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate is 6.25 mL: 2.8 g: 2.0 g: 1.8 mL, and the volume ratio of tetraethoxysilane to the mixed solvent is 1 g: 15 mL. Then, the mixture is stirred and mixed evenly. After standing at room temperature for 6 hours, the mixture was centrifuged, freeze-dried, and then calcined at 620℃ for 2 hours to obtain microspheres. Chitosan was added to a 2% (v / v) acetic acid solution, with a chitosan concentration of 2.5 wt%. The microspheres were then added to the chitosan acetic acid solution at a mass ratio of 1:10, followed by the addition of calcium chloride at a concentration of 3 wt% of the chitosan acetic acid solution. The mixture was stirred at 45℃ for 4 hours, cooled to a constant temperature, and freeze-dried to obtain the steel slag stabilizer. An electron micrograph of the steel slag stabilizer is shown below. Figure 2 As shown.

[0028] A method for preparing an environmentally friendly steel slag asphalt mixture includes the following steps: According to the specified proportions, SBS modified asphalt, steel slag, fine aggregate, mineral powder, steel slag stabilizer, and reinforcing agent are mixed evenly to obtain the final product.

[0029] Example 2 An environmentally friendly steel slag asphalt mixture is composed of the following raw materials in parts by weight: 5 parts SBS modified asphalt, 50 parts steel slag, 10 parts fine aggregate, 5 parts mineral powder, 5 parts steel slag stabilizer, and 0.5 parts reinforcing agent. The preparation process of the reinforcing agent is as follows: (1) After cleaning the basalt fiber, soak it in 0.1 mol / L hydrochloric acid solution for 30 min and then take it out. The ratio of basalt fiber to hydrochloric acid solution is 1 g: 8 mL. Wash it with deionized water until the basalt fiber is neutral and dry it to obtain pretreated basalt fiber. (2) Add silane coupling agent (vinyltriethoxysilane) to a mixed solution of ethanol and water (volume ratio of ethanol to water is 16:1), wherein the concentration of silane coupling agent in the mixed solution is 2wt%; add the basalt fiber pretreated in step (1) to a mixed solution of ethanol and water containing vinyltriethoxysilane, wherein the volume ratio of the pretreated basalt fiber to the mixed solution is 1g:15mL; let stand for 20min, and dry to obtain silane coupling agent modified basalt fiber; (3) Mix 2-methyl-4-penten-2-ol and itaconic acid, then heat and stir at 60°C for 2 hours, and then add basalt fiber modified with silane coupling agent, DMF (N,N-dimethylformamide) and AIBN (azobisisobutyronitrile), wherein the mass ratio of 2-methyl-4-penten-2-ol, itaconic acid, basalt fiber modified with silane coupling agent, DMF and AIBN is 1:2.5:1:10:0.01; continue heating and reacting for 3 hours. After the reaction is completed, filter, wash and dry to obtain the reinforcing agent.

[0030] The preparation process of the steel slag stabilizer is as follows: Tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate are added to a mixed solvent of ethanol and water (volume ratio of ethanol to water is 10:3). The volume ratio of tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate is 6.25 mL: 2.36 g: 1.5 g: 1.5 mL, and the volume ratio of tetraethoxysilane to the mixed solvent is 1 g: 15 mL. Then, the mixture is stirred and mixed evenly. The mixture was homogenized, allowed to stand at room temperature for 5 hours, centrifuged, freeze-dried, and then calcined at 600℃ for 3 hours to obtain microspheres. Chitosan was added to a 2% (v / v) acetic acid solution, with a chitosan concentration of 2 wt%. The microspheres were then added to the chitosan acetic acid solution at a mass ratio of 1:10. Calcium chloride was then added, with the amount of calcium chloride added being 3 wt% of the chitosan acetic acid solution. The mixture was stirred at 40℃ for 5 hours, cooled to a constant temperature, and freeze-dried to obtain a steel slag stabilizer.

[0031] A method for preparing an environmentally friendly steel slag asphalt mixture includes the following steps: According to the specified proportions, SBS modified asphalt, steel slag, fine aggregate, mineral powder, steel slag stabilizer, and reinforcing agent are mixed evenly to obtain the final product.

[0032] Example 3 An environmentally friendly steel slag asphalt mixture is composed of the following raw materials in parts by weight: 10 parts SBS modified asphalt, 60 parts steel slag, 15 parts fine aggregate, 10 parts mineral powder, 10 parts steel slag stabilizer, and 1 part reinforcing agent. The preparation process of the reinforcing agent is as follows: (1) After cleaning the basalt fiber, soak it in 0.3 mol / L hydrochloric acid solution for 40 min and then take it out. The ratio of basalt fiber to hydrochloric acid solution is 1 g: 10 mL. Wash it with deionized water until the basalt fiber is neutral and dry it to obtain pretreated basalt fiber. (2) Add silane coupling agent (vinyltriethoxysilane) to a mixed solution of ethanol and water (volume ratio of ethanol to water is 16:1), wherein the concentration of silane coupling agent in the mixed solution is 3wt%; add the basalt fiber pretreated in step (1) to a mixed solution of ethanol and water containing vinyltriethoxysilane, wherein the volume ratio of the pretreated basalt fiber to the mixed solution is 1g:20mL; let stand for 30min, and dry to obtain basalt fiber modified with silane coupling agent; (3) Mix 2-methyl-4-penten-2-ol and itaconic acid, then heat and stir at 70°C for 2 hours, and then add basalt fiber modified with silane coupling agent, DMF (N,N-dimethylformamide) and AIBN (azobisisobutyronitrile), wherein the mass ratio of 2-methyl-4-penten-2-ol, itaconic acid, basalt fiber modified with silane coupling agent, DMF and AIBN is 1:3:1.3:10:0.015; continue heating and reacting for 5 hours. After the reaction is completed, filter, wash and dry to obtain the reinforcing agent.

[0033] The preparation process of the steel slag stabilizer is as follows: Tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate are added to a mixed solvent of ethanol and water (volume ratio of ethanol to water is 10:3). The volume ratio of tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate is 6.25 mL: 3.2 g: 2.5 g: 2 mL, and the volume ratio of tetraethoxysilane to the mixed solvent is 1 g: 15 mL. Then, the mixture is stirred and mixed evenly. After standing at room temperature for 8 hours, the mixture was centrifuged, freeze-dried, and then calcined at 600℃ for 3 hours to obtain microspheres. Chitosan was added to a 2% (v / v) acetic acid solution, with a chitosan concentration of 3 wt%. The microspheres were then added to the chitosan acetic acid solution at a mass ratio of 1:10. Calcium chloride was then added at a concentration of 3 wt% of the chitosan acetic acid solution. The mixture was stirred at 50℃ for 3 hours, cooled to a constant temperature, and freeze-dried to obtain a steel slag stabilizer.

[0034] A method for preparing an environmentally friendly steel slag asphalt mixture includes the following steps: According to the specified proportions, SBS modified asphalt, steel slag, fine aggregate, mineral powder, steel slag stabilizer, and reinforcing agent are mixed evenly to obtain the final product.

[0035] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the reinforcing agent is replaced with basalt fiber modified with silane coupling agent; otherwise, they are the same as in Example 1.

[0036] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the steel slag stabilizer is omitted; otherwise, they are the same as Example 1.

[0037] Test case According to JTG 3410-2025 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", the freeze-thaw splitting strength ratio, Marshall stability, water-immersed Marshall residual stability, Kentenberg water immersion loss rate, low-temperature flexural tensile strain, flexural tensile strength, rutting dynamic stability, and fatigue life of the mixtures obtained in Examples 1-3 and Comparative Examples 1-2 were tested. The results are shown in Table 1.

[0038] Table 1 As shown in Table 1, the freeze-thaw splitting strength ratios of Examples 1-3 of the present invention are all higher than 90%, the water-immersed Marshall residual stability is higher than 91%, and the Kentucky water-immersed scattering loss rate is lower than 9.1%, which are far superior to Comparative Examples 1 and 2. This indicates that the asphalt mixture of the present invention has good water stability and resistance to water erosion. Comparative Example 2 omits the steel slag stabilizer. The pores of the steel slag cannot be filled, and it is prone to hydration and expansion, resulting in severe water damage. The freeze-thaw splitting strength ratio, water-immersed Marshall residual stability, and Kentucky water-immersed scattering loss rate all show varying degrees of reduction.

[0039] Examples 1-3 show higher Marshall stability and rutting dynamic stability than Comparative Examples 1 and 2, indicating that the asphalt mixture of the present invention has good high-temperature stability and rutting resistance. This is because the reinforcing agent introduced in the present invention can effectively disperse stress and inhibit deformation, and, in combination with the steel slag stabilizer, improve the density of the steel slag, thus synergistically inhibiting the high-temperature deformation of the material. Comparative Example 1 lacks an organic graft layer in its reinforcing agent, resulting in unstable three-dimensional support; Comparative Example 2 lacks a steel slag stabilizer, leading to a weak interface between the steel slag and asphalt, and both exhibit significantly reduced high-temperature deformation resistance.

[0040] Examples 1-3 show superior low-temperature flexural tensile strain, flexural tensile strength, and fatigue life compared to Comparative Examples 1 and 2. Comparative Example 1 lacks an organic grafted layer, resulting in insufficient toughness and deformation capacity. The reinforcing agent does not bond firmly to the asphalt, failing to buffer stress and delay crack propagation. Comparative Example 2 lacks a steel slag stabilizer, leading to easy interface debonding and inferior low-temperature crack resistance compared to Example 1. These results demonstrate that the asphalt mixture of this invention exhibits strong deformation resistance and excellent low-temperature crack resistance and fatigue resistance.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. An environmentally friendly steel slag asphalt mixture, characterized in that, It is composed of the following raw materials in parts by weight: 5-10 parts SBS modified bitumen, 50-60 parts steel slag, 10-15 parts fine aggregate, 5-10 parts mineral powder, 5-10 parts steel slag stabilizer, and 0.5-1 parts reinforcing agent. The preparation process of the reinforcing agent is as follows: (1) Basalt fibers were washed, soaked in an acidic solution, and then removed to obtain pretreated basalt fibers; (2) The basalt fibers pretreated in step (1) are added to a mixed solution of ethanol and water containing silane coupling agent, allowed to stand, and dried to obtain silane coupling agent modified basalt fibers. (3) Mix 2-methyl-4-penten-2-ol and itaconic acid, heat and stir, then add basalt fiber modified with silane coupling agent, DMF and AIBN, and continue heating to obtain the reinforcing agent.

2. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, In step (1), the ratio of basalt fiber to acidic solution is 1g:8-10mL; the acidic solution is a hydrochloric acid solution with a concentration of 0.1-0.3mol / L.

3. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, In step (2), the ratio of the pretreated basalt fiber to the mixed solution is 1g:15-20mL; the concentration of the silane coupling agent in the mixed solution of ethanol and water containing the silane coupling agent is 2-3wt%, the silane coupling agent is vinyltriethoxysilane, and the volume ratio of ethanol to water is 16:

1.

4. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, In step (3), the mass ratio of 2-methyl-4-penten-2-ol, itaconic acid, silane coupling agent-modified basalt fiber, DMF and AIBN is 1:(2.5-3):(1-1.3):10:(0.01-0.015).

5. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, The soaking time in step (1) is 30-40 min; the standing time in step (2) is 20-30 min; the heating and stirring temperature in step (3) is 60-70℃ and the time is 1-2 h; the heating reaction time is 3-5 h.

6. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, The preparation process of the steel slag stabilizer is as follows: Tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate are added to a mixed solvent of ethanol and water. After stirring and mixing evenly, the mixture is allowed to stand at room temperature for 5-8 hours. After centrifugation, freeze drying, and calcination, microspheres are obtained. The microspheres are added to an acetic acid solution of chitosan, and then calcium chloride is added. The mixture is stirred at 40-50℃ for 3-5 hours to obtain the steel slag stabilizer.

7. The environmentally friendly steel slag asphalt mixture according to claim 6, characterized in that, The ratio of tetraethoxysilane, calcium nitrate, hexadecyltrimethylammonium bromide, and triethyl citrate is 6.25 mL: 2.36-3.2 g: 1.5-2.5 g: 1.5-2 mL; the ratio of tetraethoxysilane to the mixed solvent is 1 g: 15 mL; the volume ratio of ethanol to water in the mixed solvent is 10:3; the calcination temperature is 600-650℃, and the time is 1-3 h.

8. The environmentally friendly steel slag asphalt mixture according to claim 6, characterized in that, The mass ratio of the microspheres to the acetic acid solution of chitosan is 1:10; the amount of calcium chloride added is 3 wt% of the acetic acid solution of chitosan; the concentration of chitosan in the acetic acid solution of chitosan is 2-3 wt%; and the volume concentration of the acetic acid solution is 2%.

9. The environmentally friendly steel slag asphalt mixture according to claim 1, characterized in that, The SBS modified asphalt is type I-B; the steel slag contains ≤3% calcium oxide, 3-10% magnesium oxide, 1-3% manganese oxide, ≤2% iron, and has a particle size of 5-10mm; the fine aggregate is 0.1-3mm limestone manufactured sand; and the mineral powder is limestone mineral powder with a particle size of 40-75μm.

10. A method for preparing an environmentally friendly steel slag asphalt mixture according to any one of claims 1-9, characterized in that, Includes the following steps: According to the specified proportions, SBS modified asphalt, steel slag, fine aggregate, mineral powder, steel slag stabilizer, and reinforcing agent are mixed evenly to obtain the final product.

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