An asphalt anti-stripping agent, its preparation method and application

Abstract

This invention discloses an asphalt anti-stripping agent, its preparation method, and its application. The asphalt anti-stripping agent of this invention, by weight, comprises the following components: tailings powder: 100 parts, lime powder: 50-70 parts, fatty alcohol polyoxyethylene ether phosphate: 3-15 parts, organosilane: 2-8 parts, and composite modifier: 15-50 parts. The asphalt anti-stripping agent of this invention can improve the adhesion between tailings aggregate and asphalt, and enhance the water stability of tailings-asphalt mixtures.

Description

Technical Field

[0001] This invention relates to the field of asphalt additives, specifically to an asphalt anti-stripping agent, its preparation method, and its application. Background Technology

[0002] Iron tailings are the lower-value components of iron ore produced during processing and utilization. They are a significant part of mine solid waste and a valuable secondary resource. Globally, iron tailings are mainly distributed in China, Brazil, and Australia. Statistics show that the annual cumulative increase in global tailings reaches 5 to 7 billion tons, with iron tailings accounting for about half. Currently, the total iron tailings stockpile in China and Brazil alone exceeds 10 billion tons.

[0003] The chemical composition of iron tailings is mainly composed of oxides of silicon, aluminum, iron, calcium, and magnesium, with quartz and feldspar minerals as the main minerals. This composition is very similar to that of natural sand minerals, providing a necessary foundation for iron tailings to be used as raw materials for building materials. New building materials are those that improve the performance and functionality of traditional building materials, characterized by high strength, lightweight, energy efficiency, and low environmental pollution. Applying iron tailings to the field of new building materials meets the dual needs of environmental and economic development.

[0004] Compared to conventional aggregates, iron tailings aggregates meet aggregate specifications in terms of physical and mechanical properties. However, iron tailings are high-silica aggregates with poor adhesion to asphalt, easily leading to water damage such as looseness, pitting, potholes, and pumping on the road surface. The key to water damage lies in insufficient adhesion between asphalt and aggregates, causing the asphalt film to detach from the aggregate surface. Therefore, to use tailings aggregates while preventing water damage, improving the adhesion between asphalt and aggregates is crucial. The simplest and most effective method is to add anti-stripping agents. However, currently, there are no anti-stripping agents specifically for tailings aggregates, and most commonly used anti-stripping agents are amine compounds that act directly on asphalt, exhibiting poor thermal stability and easily leading to performance failure.

[0005] CN102174264A discloses a method for preparing an anti-stripping agent for road asphalt. The anti-stripping agent comprises the following components: 50-65 parts of polyethylene glycol; 10-30 parts of alkoxyliphatic polyamines; 5-15 parts of alkylamines; 5-15 parts of polyamines; 1-2 parts of alcohol ether compounds; and 13-29 parts of diethanolamine. However, aliphatic amine anti-stripping agents have poor thermal stability and mainly rely on physical adsorption, limiting their application.

[0006] CN108623207A discloses an asphalt anti-stripping agent containing phosphate salts and its application method. The anti-stripping agent is composed of sodium dodecyl phosphate and octadecyltrimethylammonium chloride. During application, the anti-stripping agent needs to be mixed evenly with hot asphalt, but it does not modify the aggregate. When added in small amounts, it is prone to uneven dispersion, resulting in limited anti-stripping effect.

[0007] In summary, developing an asphalt anti-stripping agent with good thermal stability and significantly improved adhesion, and comprehensively utilizing iron ore solid waste, has significant social and economic implications. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide an asphalt anti-stripping agent, its preparation method, and its application. The asphalt anti-stripping agent of the present invention can improve the adhesion between tailings aggregate and asphalt, and enhance the water stability of tailings-asphalt mixtures.

[0009] The first aspect of this invention provides an asphalt anti-stripping agent, comprising the following components by weight:

[0010] Tailings powder: 100 parts;

[0011] Lime powder: 50-70 parts, preferably 55-70 parts;

[0012] Fatty alcohol polyoxyethylene ether phosphate: 3-15 parts, preferably 5-10 parts;

[0013] Organosilane: 2-8 parts, preferably 2-5 parts;

[0014] Composite modifier: 15-50 parts, preferably 20-40 parts.

[0015] Based on the mass of the tailings powder, the chemical composition of the tailings powder includes: 55%–60% SiO2, 10%–18% Fe2O3, 10%–15% Al2O3, and 6%–13% CaO. The particle size of the tailings powder meets the following requirements: <0.075mm standard square sieve passing rate of 85%–100%. The tailings powder is generally iron tailings powder obtained after magnetic separation in the mining area.

[0016] The lime powder is industrial-grade hydrated lime powder, wherein Ca(OH)2 > 90 wt% and the particle size is 80-500 mesh.

[0017] The fatty alcohol polyoxyethylene ether phosphate AEO-P has the general formula RO(CH2CH2O)nPO3H2, where n is an integer from 3 to 9. The fatty alcohol ROH used in the synthesis of the fatty alcohol polyoxyethylene ether phosphate is a normal fatty alcohol and / or an isomeric fatty alcohol, selected from C8-18 alcohols, preferably one or more of isooctanol, lauryl alcohol, isodecyl alcohol, and cetyl alcohol.

[0018] The organosilane is a mixture of aminosilane and long-chain organosilane, wherein the aminosilane accounts for 30% to 50% of the total mass of the organosilane, and the long-chain organosilane accounts for 50% to 70% of the total mass of the organosilane.

[0019] The aminosilane is one or more of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, N-[[[2-(trimethoxysilyl)ethyl]phenyl]methyl]-1,2-ethylenediamine, N-(6-aminohexyl)aminomethyltriethoxysilane, 3-(4-ureaamino)propyltriethoxysilane, and N-(2-aminoethyl)-11-aminoundecyltrimethoxysilane.

[0020] The long-chain organosilane is one or more of dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecylmethyldimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0021] The composite modifier comprises the following components by weight:

[0022] Nano silica: 100 parts;

[0023] 3-Glycidyl etheroxypropylmethyldiethoxysilane (GPTMS): 3-8 parts, preferably 3-6 parts;

[0024] Polyethyleneimine (PEI): 3 to 10 parts, preferably 5 to 8 parts.

[0025] Both the nano-silica and 3-glycidyl etheroxypropylmethyldiethoxysilane are commercially available products.

[0026] The molecular weight of the polyethyleneimine is 1,000 to 70,000, preferably one or more of 1,000, 20,000, and 70,000.

[0027] A second aspect of the present invention provides a method for preparing the above-mentioned asphalt anti-stripping agent, comprising:

[0028] (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution;

[0029] (2) Preparation of composite modifier;

[0030] (3) Mix the tailings powder with lime powder and composite modifier evenly to obtain a pre-mixed powder;

[0031] (4) Spray the pre-mixed liquid obtained in step (1) evenly onto the pre-mixed powder obtained in step (3), and dry it to obtain asphalt anti-stripping agent.

[0032] In step (1), fatty alcohol polyoxyethylene ether phosphate can be prepared by the following method: Under nitrogen protection, 3 parts by weight of fatty alcohol polyoxyethylene ether (AEO) are added first, and preferably 1 part by weight of P2O5 is added in batches while stirring. The temperature is raised and stirring is continued until hydrolysis is carried out to obtain fatty alcohol polyoxyethylene ether phosphate. The heating temperature is 80-90℃, the stirring time after heating is 3-6 hours, the hydrolysis temperature is consistent with the reaction temperature, the hydrolysis time is 1.5-3 hours, and the amount of water added is 3%-7% of the total product.

[0033] In step (1), the mixing temperature of the fatty alcohol polyoxyethylene ether phosphate and the organosilane is 45-65°C.

[0034] In step (2), the preparation process of the composite modifier is as follows:

[0035] Nano-silica and 3-glycidyl etheroxypropylmethyldiethoxysilane (GPTMS) were mixed in anhydrous ethanol and reacted under a first heating reflux condition. After the reaction was completed, polyethyleneimine (PEI) was added and reacted under a second heating reflux condition. After cooling, the mixture was filtered, washed, and dried to obtain a composite modifier.

[0036] The reaction temperature of the first heating reflux is 90℃~130℃, preferably 100℃~115℃, and the time is 12~18h.

[0037] The reaction temperature of the second heating reflux is 90℃~120℃, preferably 100℃~110℃, and the time is 20~24h.

[0038] The first reflux temperature is preferably 3 to 10°C higher than the second reflux temperature.

[0039] The filtration and washing can be performed using conventional methods in this field.

[0040] The drying temperature is 80℃~120℃, and the time is 0.5~5h, preferably 3~5h.

[0041] The tailings powder mentioned in step (3) is obtained by drying and grinding iron tailings slag, wherein the passing rate of grinding to <0.075mm is 85-100%.

[0042] The iron tailings slag is dried at a temperature of 90–110°C for 3–5 hours.

[0043] The drying temperature in step (4) is 100-105℃ and the drying time is 2-5h.

[0044] The third aspect of the present invention discloses the application of the above-mentioned asphalt anti-stripping agent in asphalt mixtures.

[0045] The asphalt mixture is a tailings aggregate asphalt mixture.

[0046] The application includes: incorporating the asphalt anti-stripping agent into the mineral powder of the tailings aggregate asphalt mixture, wherein the amount of asphalt anti-stripping agent incorporated accounts for more than 80 wt% of the mineral powder mass, preferably 80 wt% to 90 wt%, and the coarse aggregate and fine aggregate in the tailings aggregate asphalt mixture are both iron ore waste rock, and the mineral powder is iron tailings powder after magnetic separation.

[0047] Compared with the prior art, the present invention has the following characteristics:

[0048] (1) The asphalt anti-stripping agent of the present invention plays multiple roles. The incorporation of hydrated lime powder component, due to its strong alkalinity and high chemical adsorption energy, not only improves the acidic environment of the aggregate surface, but also has a larger specific surface area, resulting in more complete adsorption of asphalt. The fatty alcohol polyoxyethylene ether phosphate has different functional groups at both ends. One end undergoes hydrogen bonding adsorption with the hydroxyl groups on the aggregate surface, while the other end is entangled and cross-linked with the asphalt polymer, thereby enhancing the overall adhesion of the asphalt mixture. The synergistic effect of aminosilane and long-chain organosilane in the organosilane improves the bonding ability of acidic aggregates and matrix asphalt, and enhances the adhesion between asphalt and aggregate.

[0049] (2) The composite modifier in this invention is a modified nano silica, which can not only be tightly adsorbed and bound to the aggregate, but the modified branched active groups can also react with hydroxyl, carboxyl, unsaturated bonds, etc. in the asphalt, tightly binding the asphalt and aggregate interface and improving the anti-stripping performance of the asphalt mixture.

[0050] (3) The tailings asphalt mixture obtained by using the asphalt anti-stripping agent of the present invention not only significantly enhances water stability, but also improves high temperature stability and low temperature crack resistance, thus comprehensively improving the road performance of the mixture. Moreover, all road performance indicators meet the road pavement usage index requirements in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004), promoting the comprehensive utilization of tailings solid waste and providing a good foundation for the subsequent application of tailings asphalt mixture. Detailed Implementation

[0051] The technical solution of the present invention is further described below through embodiments, but these embodiments cannot limit the scope of protection of the present invention, and the wt% involved refers to the mass fraction.

[0052] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0053] The preparation method of fatty alcohol polyoxyethylene ether phosphate used in the examples and comparative examples is as follows: Under nitrogen protection, 3 parts by weight of fatty alcohol polyoxyethylene ether AEO (the fatty alcohol used to synthesize fatty alcohol polyoxyethylene ether is isooctanol, n is 6) are added first. Then, 1 part by weight of P2O5 is added in batches while stirring. The temperature is raised and stirring is continued. After hydrolysis, fatty alcohol polyoxyethylene ether phosphate is obtained. The batch addition time of P2O5 is 2 hours, the heating temperature is 80°C, the stirring time is 4 hours, the hydrolysis temperature is consistent with the reaction temperature, the hydrolysis time is 2 hours, and the amount of water added for hydrolysis is 4% of the total mass of the added materials.

[0054] The tailings powder used in the examples and comparative examples, based on the mass of the tailings powder, has the following chemical composition: 58% SiO2, 17% Fe2O3, 13% Al2O3, and 12% CaO.

[0055] The lime powder is industrial-grade hydrated lime powder, with a Ca(OH)2 content of 96.4 wt% and a particle size of 120 mesh.

[0056] Example 1

[0057] (1) Mix 6 parts of fatty alcohol polyoxyethylene ether phosphate and 3 parts of organosilane (a mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane (of which dodecyltrimethoxysilane accounts for 60 wt%) and stir evenly at 50°C to obtain a pre-mixed solution.

[0058] (2) 100 parts of nano silica and 5 parts of 3-glycidyl etheroxypropylmethyldiethoxysilane (GPTMS) were mixed in anhydrous ethanol and heated under reflux at 110°C for 12 h. After the reaction was completed, 6 parts of polyethyleneimine (PEI) with a molecular weight of 20,000 were added and heated under reflux at 100°C for 24 h. After the reaction was completed, the mixture was filtered, washed, and dried at 100°C for 5 h to obtain the composite modifier for later use.

[0059] (3) Dry the iron tailings slag, grind it to <0.075mm with a throughput of 90%, mix 100 parts of tailings powder, 55 parts of lime powder and 20 parts of composite modifier evenly to obtain pre-mixed powder.

[0060] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 105℃ for 4 hours to obtain asphalt anti-stripping agent A1.

[0061] Example 2

[0062] (1) Mix 6 parts of fatty alcohol polyoxyethylene ether phosphate and 4 parts of organosilane (a mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane, wherein dodecyltrimethoxysilane accounts for 60 wt%) and stir evenly at 55°C to obtain a pre-mixed solution.

[0063] (2) Mix 100 parts of nano silica and 5 parts of GPTMS in anhydrous ethanol and heat at 110°C under reflux for 12 h. After the reaction is complete, add 6 parts of PEI with a molecular weight of 20,000 and heat at 100°C under reflux for 24 h. After the reaction is complete, filter, wash and dry at 100°C for 5 h to obtain the composite modifier for later use.

[0064] (3) Dry the iron tailings slag, grind it to <0.075mm with a throughput of 92%, mix 100 parts of tailings powder, 55 parts of lime powder and 25 parts of composite modifier evenly to obtain pre-mixed powder.

[0065] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 102℃ for 5 hours to obtain asphalt anti-stripping agent A2.

[0066] Example 3

[0067] (1) Mix 8 parts of fatty alcohol polyoxyethylene ether phosphate and 3 parts of organosilane (a mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and hexadecyltrimethoxysilane, wherein hexadecyltrimethoxysilane accounts for 70 wt%) and stir evenly at 55°C to obtain a pre-mixed solution.

[0068] (2) Mix 100 parts of nano silica and 6 parts of GPTMS in anhydrous ethanol and heat at 110°C under reflux for 12 h. After the reaction is complete, add 7 parts of PEI with a molecular weight of 20,000 and heat at 100°C under reflux for 24 h. After the reaction is complete, filter, wash and dry at 100°C for 5 h to obtain the composite modifier for later use.

[0069] (3) Dry the iron tailings slag, grind it to <0.075mm with a throughput of 90%, mix 100 parts of tailings powder, 60 parts of lime powder and 20 parts of composite modifier evenly to obtain pre-mixed powder.

[0070] (4) Spray the pre-mixed liquid evenly onto the pre-mixed powder and dry it at 105℃ for 4 hours to obtain asphalt anti-stripping agent A3.

[0071] Example 4

[0072] (1) Mix 6 parts of fatty alcohol polyoxyethylene ether phosphate and 3 parts of organosilane (a mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane, wherein dodecyltrimethoxysilane accounts for 60 wt%) and stir evenly at 60 °C to obtain a pre-mixed solution.

[0073] (2) Mix 100 parts of nano silica and 5 parts of GPTMS in anhydrous ethanol and heat at 110°C under reflux for 16 h. After the reaction, add 3 parts of PEI with a molecular weight of 20,000 and 4 parts of PEI with a molecular weight of 70,000. Heat at 105°C under reflux for 24 h. After the reaction, filter, wash and dry at 100°C for 5 h to obtain the composite modifier for later use.

[0074] (3) Dry the iron tailings slag, grind it to <0.075mm with a throughput of 90%, mix 100 parts of tailings powder, 55 parts of lime powder and 20 parts of composite modifier evenly to obtain pre-mixed powder.

[0075] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 105℃ for 4 hours to obtain asphalt anti-stripping agent A4.

[0076] Example 5

[0077] (1) Mix 6 parts of fatty alcohol polyoxyethylene ether phosphate and 3 parts of organosilane (a mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane, wherein dodecyltrimethoxysilane accounts for 60 wt%) and stir evenly at 55°C to obtain a pre-mixed solution.

[0078] (2) Mix 100 parts of nano silica and 5 parts of GPTMS in anhydrous ethanol and heat at 110°C under reflux for 16 h. After the reaction, add 2 parts of PEI with a molecular weight of 20,000, 3 parts of PEI with a molecular weight of 70,000 and 2 parts of PEI with a molecular weight of 1,000. Heat at 105°C under reflux for 24 h. After the reaction, filter, wash and dry at 100°C for 5 h to obtain the composite modifier for later use.

[0079] (3) Dry the iron tailings slag, grind it to <0.075mm with a throughput of 95%, mix 100 parts of tailings powder, 55 parts of lime powder and 20 parts of composite modifier evenly to obtain pre-mixed powder.

[0080] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 105℃ for 4 hours to obtain asphalt anti-stripping agent A5.

[0081] Comparative Example 1

[0082] Same as Example 1, except that lime powder is not added during the preparation process to obtain asphalt mixture anti-stripping agent B1.

[0083] Comparative Example 2

[0084] Same as Example 1, except that nano-silica is directly used instead of modified nano-silica in the preparation process to obtain asphalt mixture anti-stripping agent B2.

[0085] Comparative Example 3

[0086] Same as Example 1, except that the preparation method of modified nano-silica is as follows: 6 parts of biomimetic material methacrylamide dopamine and 100 parts of nano-silica ethanol dispersion are mixed and stirred evenly for 5 minutes to obtain a mixture. After the reaction is completed, the mixture is filtered, washed, and dried at 100°C for 5 hours to obtain modified nano-silica composite modifier for later use. Finally, exfoliating agent B3 is obtained.

[0087] Comparative Example 4

[0088] Same as Example 1, except that no organosilane (N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane mixture) is added during the preparation process, resulting in asphalt mixture anti-stripping agent B4.

[0089] Comparative Example 5

[0090] Same as Example 1, except that fatty alcohol polyoxyethylene ether phosphate is not added during the preparation process, resulting in asphalt mixture anti-stripping agent B5.

[0091] Comparative Example 6

[0092] Same as Example 1, except that vinyltriethoxysilane is used instead of fatty alcohol polyoxyethylene ether phosphate in the preparation process to obtain anti-stripping agent B6.

[0093] According to the usage method, the asphalt anti-stripping agents of Examples 1-5 and Comparative Examples 1-6 were incorporated into the mineral powder of the iron tailings aggregate asphalt mixture at an addition rate of 80 wt% (80 wt% of the mineral powder mass), and then the asphalt mixture was prepared. In the iron tailings aggregate asphalt mixture, both the coarse and fine aggregates were iron ore waste rock, the mineral powder was iron tailings powder, the base asphalt was Qilu 70A asphalt, and the asphalt mixture gradation type was AC-20. The road performance of the asphalt mixture was evaluated.

[0094] The road performance of asphalt mixtures was tested according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). Among them, the water stability was tested by the residual stability MS0 of the immersion Marshall test (T 0709-2011) and the freeze-thaw splitting strength ratio TSR of the freeze-thaw splitting test (T0729-2000). The high temperature stability was tested by the dynamic stability of the rutting test (T0719-2011). The low temperature crack resistance was tested by the flexural tensile strength and maximum flexural tensile strain of the low temperature bending test (T0715-2011). The results are shown in Table 1.

[0095] Table 1. Properties of the asphalt mixtures prepared in Examples 1-5 and Comparative Examples 1-6

[0096]

[0097] As can be seen from the results in Table 1, the iron tailings asphalt mixture prepared with the asphalt anti-stripping agent of the present invention has good water stability and high and low temperature performance, and all road performance indicators meet the requirements of road pavement in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004).

Claims

1. An asphalt anti-stripping agent, characterized in that, By weight, it includes the following components: Iron tailings powder: 100 parts; Lime powder: 50-70 parts; Fatty alcohol polyoxyethylene ether phosphate: 3~15 parts; Organosilanes: 2-8 parts; Composite modifier: 15-50 parts; The composite modifier comprises the following components by weight: Nano-silica: 100 parts; 3-Glycidyl etheroxypropylmethyldiethoxysilane: 3-8 parts; Polyethyleneimine: 3-10 parts.

2. The asphalt anti-stripping agent according to claim 1, characterized in that, By weight, it includes the following components: Iron tailings powder: 100 parts; Lime powder: 55-70 parts; Fatty alcohol polyoxyethylene ether phosphate: 5-10 parts; Organosilanes: 2-5 parts; Composite modifier: 20-40 parts.

3. The asphalt anti-stripping agent according to claim 1, characterized in that, Based on the mass of the iron tailings powder, the chemical composition of the iron tailings powder includes: 55%~60% SiO2, 10%~18% Fe2O3, 10%~15% Al2O3, and 6%~13% CaO.

4. The asphalt anti-stripping agent according to claim 1, characterized in that, The fatty alcohol polyoxyethylene ether phosphate has the general formula RO(CH2CH2O)nPO3H2, where n is an integer from 3 to 9; wherein the fatty alcohol ROH used in the synthesis of the fatty alcohol polyoxyethylene ether phosphate is a normal fatty alcohol and / or an isomeric fatty alcohol, selected from C8-18 alcohols.

5. The asphalt anti-stripping agent according to claim 4, characterized in that, The fatty alcohol ROH used in the synthesis of fatty alcohol polyoxyethylene ether phosphate is one or more of isooctanol, lauryl alcohol, isodecyl alcohol, and cetyl alcohol.

6. The asphalt anti-stripping agent according to claim 1, characterized in that, The organosilane is a mixture of aminosilane and long-chain organosilane, wherein the aminosilane accounts for 30% to 50% of the total mass of the organosilane, and the long-chain organosilane accounts for 50% to 70% of the total mass of the organosilane.

7. The asphalt anti-stripping agent according to claim 6, characterized in that, The aminosilane is one or more of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, N-[[[2-(trimethoxysilyl)ethyl]phenyl]methyl]-1,2-ethylenediamine, N-(6-aminohexyl)aminomethyltriethoxysilane, 3-(4-ureaamino)propyltriethoxysilane, and N-(2-aminoethyl)-11-aminoundecyltrimethoxysilane; and / or, the long-chain organosilane is one or more of dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecylmethyldimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

8. The asphalt anti-stripping agent according to claim 1, characterized in that, The composite modifier comprises the following components by weight: Nano silica: 100 parts; 3-Glycidyl etheroxypropylmethyldiethoxysilane: 3-6 parts; Polyethyleneimine: 5-8 parts.

9. A method for preparing the asphalt anti-stripping agent according to any one of claims 1-8, comprising: (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution; (2) Preparation of composite modifier; (3) Mix the tailings powder with lime powder and composite modifier evenly to obtain a pre-mixed powder; (4) Spray the premixed liquid obtained in step (1) evenly onto the premixed powder obtained in step (3), and dry it to obtain asphalt anti-stripping agent.

10. The preparation method according to claim 9, characterized in that, In step (1), the mixing temperature of the fatty alcohol polyoxyethylene ether phosphate and organosilane is 45~65℃.

11. The preparation method according to claim 9, characterized in that, In step (2), the preparation process of the composite modifier is as follows: Nano-silica and 3-glycidyl etheroxypropylmethyldiethoxysilane were mixed in anhydrous ethanol and reacted under a first heating reflux condition. After the reaction was completed, polyethyleneimine was added and reacted under a second heating reflux condition. After cooling, the mixture was filtered, washed, and dried to obtain a composite modifier.

12. The preparation method according to claim 11, characterized in that, The first reflux reaction temperature is 90℃~130℃ and the time is 12~18h, and / or the second reflux reaction temperature is 90℃~120℃ and the time is 20~24h.

13. The preparation method according to claim 12, characterized in that, The reaction temperature of the first heating reflux is 100℃~115℃ and / or the reaction temperature of the second heating reflux is 100℃~110℃.

14. The preparation method according to claim 12 or 13, characterized in that, The reaction temperature of the first heating reflux is 3~10℃ higher than that of the second heating reflux.

15. The preparation method according to claim 9, characterized in that, The drying temperature in step (4) is 100~105℃ and the drying time is 2~5h.

16. The use of the asphalt anti-stripping agent according to any one of claims 1-8 or the asphalt prepared by any one of claims 9-15 in asphalt mixtures.

17. The application according to claim 16, characterized in that, The application includes: incorporating the asphalt anti-stripping agent into the mineral powder of the tailings aggregate asphalt mixture, wherein the amount of asphalt anti-stripping agent incorporated accounts for more than 80 wt% of the mineral powder mass, and the coarse aggregate and fine aggregate in the tailings aggregate asphalt mixture are both iron ore waste rock, and the mineral powder is iron tailings powder after magnetic separation.

18. The application according to claim 17, characterized in that, The amount of asphalt anti-stripping agent added accounts for 80wt%~90wt% of the mineral powder mass.

Images