A road asphalt anti-stripping agent, its preparation method and application

Abstract

This invention discloses a road asphalt anti-stripping agent, its preparation method, and its application. The road asphalt anti-stripping agent of this invention, by weight, comprises the following components: composite powder: 100 parts, fatty alcohol polyoxyethylene ether phosphate: 3-15 parts, soda lignin: 40-80 parts, organosilane: 2-8 parts, and modified nano-silica: 15-50 parts. This road asphalt anti-stripping agent 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 road asphalt additives, specifically to a road asphalt anti-stripping agent, its preparation method, and its application. Background Technology

[0002] Large-scale accumulation of tailings can easily lead to geological disasters, environmental pollution, and waste of land resources. In recent years, the comprehensive utilization of tailings has been increasing, but none of these applications have reached a large scale. However, using tailings as an aggregate substitute in high-grade asphalt concrete pavement materials can not only improve the comprehensive utilization value of iron tailings but also significantly reduce the construction cost of asphalt pavements.

[0003] Compared to conventional aggregates, 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.

[0004] 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 alkoxy-aliphatic 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.

[0005] 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.

[0006] 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

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a road asphalt anti-stripping agent, its preparation method, and its application. This road asphalt anti-stripping agent can improve the adhesion between tailings aggregate and asphalt, and enhance the water stability of tailings asphalt mixtures.

[0008] The first aspect of this invention provides a road asphalt anti-stripping agent, comprising the following components by weight:

[0009] Composite powder: 100 parts;

[0010] Fatty alcohol polyoxyethylene ether phosphate: 3-15 parts, preferably 5-10 parts;

[0011] Soda lignin: 40-80 parts, preferably 60-75 parts;

[0012] Organosilane: 2-8 parts, preferably 2-5 parts;

[0013] Modified nano-silica: 15-50 parts, preferably 20-40 parts.

[0014] The composite powder is a mixture of at least two of CaCO3 powder, Ca(OH)2 powder, and NaOH powder, preferably a mixture of all three. The average particle size of the composite powder is 20–50 μm.

[0015] The composite powder is preferably a mixture of CaCO3 powder, Ca(OH)2 powder and NaOH powder. Based on the total mass of the composite powder, CaCO3 powder accounts for 30% to 50% of the total mass, Ca(OH)2 powder accounts for 30% to 40% of the total mass, and NaOH powder accounts for 10% to 40% of the total mass.

[0016] 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, such as isooctanol, lauryl alcohol, isodecyl alcohol, and cetyl alcohol, or one or more of these.

[0017] The properties of the soda lignin include: a density of 0.3–0.5 g / cm³. 3 The average particle size is 25-40 μm, the purity is not less than 70 wt%, the ash content is not greater than 8 wt%, the water content is not greater than 10 wt%, and the degradation temperature is 200-500℃.

[0018] The soda lignin can be extracted using a conventional soda pulping process, wherein the soda pulp is prepared using sodium hydroxide.

[0019] 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.

[0020] 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.

[0021] The long-chain organosilane is one or more of dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecylmethyldimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0022] The modified nano-silica, by weight, comprises the following components:

[0023] Nano silica: 100 parts;

[0024] 3-Glycidyl etheroxypropylmethyldiethoxysilane (GPTMS): 3-8 parts, preferably 3-6 parts;

[0025] Polyethyleneimine (PEI): 3 to 10 parts, preferably 5 to 8 parts.

[0026] Both the nano-silica and 3-glycidyl etheroxypropylmethyldiethoxysilane are commercially available products.

[0027] The molecular weight of the polyethyleneimine is 1,000 to 70,000, preferably one or more of 1,000, 20,000, and 70,000.

[0028] A second aspect of the present invention provides a method for preparing the above-mentioned anti-stripping agent for road asphalt, comprising:

[0029] (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution;

[0030] (2) Preparation of modified nano-silica;

[0031] (3) Mix the composite powder, soda lignin and modified nano silica evenly to obtain a pre-mixed powder;

[0032] (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 the asphalt anti-stripping agent.

[0033] 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.

[0034] In step (1), the mixing temperature of the fatty alcohol polyoxyethylene ether phosphate and the organosilane is 45-65°C.

[0035] In step (2), the method for preparing modified nano-silica is as follows:

[0036] Nano-silica was mixed with 3-glycidyl etheroxypropylmethyldiethoxysilane (GPTMS) 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 modified nano-silica.

[0037] The reaction temperature of the first heating reflux is 90℃~130℃, preferably 100℃~115℃, and the time is 12~18h.

[0038] The reaction temperature of the second heating reflux is 90℃~120℃, preferably 95℃~110℃, and the time is 20~24h.

[0039] The first reflux temperature is preferably 3 to 10°C higher than the second reflux temperature.

[0040] The filtration and washing can be performed using conventional methods in this field.

[0041] The drying temperature is 80℃~120℃, and the time is 0.5~5h, preferably 3~5h.

[0042] In step (4), the drying temperature is 95-110℃ and the drying time is 2-5h.

[0043] The third aspect of this invention discloses the application of the above-mentioned road asphalt anti-stripping agent in asphalt mixtures.

[0044] The asphalt mixture is a tailings aggregate asphalt mixture.

[0045] The application includes: incorporating the road asphalt anti-stripping agent into the mineral powder of the tailings aggregate asphalt mixture, wherein the amount of road asphalt anti-stripping agent incorporated accounts for 30wt% to 50wt% 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.

[0046] Compared with the prior art, the present invention has the following characteristics:

[0047] (1) The asphalt anti-stripping agent of the present invention exhibits appropriate alkalinity and acts as part of the mineral powder, which can improve the acidic environment on the surface of aggregates. Moreover, it has a large specific surface area and can adsorb asphalt more fully. 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 surface of aggregates, and the other end is entangled and crosslinked with asphalt polymers, which strengthens the overall adhesion of the asphalt mixture. Furthermore, the different functional groups at both ends of the fatty alcohol polyoxyethylene ether phosphate can synergistically cooperate with aminosilanes and long-chain organosilanes in organosilanes to improve the bonding ability of acidic aggregates and matrix asphalt, and enhance the adhesion between asphalt and aggregates.

[0048] (2) The modified nano silica in this invention can not only be tightly adsorbed and bound to the aggregate, but the branched active groups introduced by the modification can also react with the hydroxyl, carboxyl, and unsaturated bonds in the asphalt, tightly binding the asphalt and aggregate interface and improving the anti-stripping performance of the asphalt mixture; the soda lignin in this invention can not only adjust the pH of the environment together with the composite powder, but also improve the anti-aging ability of the asphalt, prevent the adhesion of the asphalt from decreasing after aging, and has good compatibility with the asphalt. Under the premise of having little impact on the low temperature performance, it can significantly improve the high temperature stability of the asphalt mixture.

[0049] (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

[0050] 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.

[0051] 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.

[0052] The preparation method of fatty alcohol polyoxyethylene ether phosphate used in the examples and comparative examples is as follows: Under nitrogen protection, 3 parts of fatty alcohol polyoxyethylene ether AEO (the fatty alcohol used to synthesize fatty alcohol polyoxyethylene ether is isooctanol, n is 6) are added first, and 1 part 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 2h, the heating temperature is 80℃, the stirring time is 4h, the hydrolysis temperature is consistent with the reaction temperature, the hydrolysis time is 2h, and the amount of water added for hydrolysis is 4% of the total mass of all materials.

[0053] Example 1

[0054] (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 50 °C to obtain a pre-mixed solution.

[0055] (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 105°C for 24 h. After the reaction was completed, the mixture was filtered, washed, and dried at 100°C for 5 h to obtain modified nano silica for later use.

[0056] (3) Mix 100 parts of composite powder (of which CaCO3 powder, Ca(OH)2 powder, and NaOH powder are 50 parts, 30 parts, and 20 parts respectively) and 60 parts of soda lignin (density 0.45 g / cm³). 3 20 parts of modified nano-silica (with an average particle size of 35.6 μm, purity of 80 wt%, ash content of 7 wt%, water content of 8.2 wt%, and degradation temperature of 260 ℃) were mixed evenly to obtain a pre-mixed powder.

[0057] (4) Spray the pre-mixed liquid evenly onto the pre-mixed powder and dry it at 105℃ for 4 hours to obtain road asphalt anti-stripping agent A1.

[0058] Example 2

[0059] (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 50 °C to obtain a pre-mixed solution.

[0060] (2) Mix 100 parts of nano silica and 5 parts of GPTMS in anhydrous ethanol and heat at 106°C under reflux for 12 h. After the reaction is complete, add 6 parts of PEI with a molecular weight of 20000 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 modified nano silica for later use.

[0061] (3) Mix 100 parts of composite powder (of which, CaCO3 powder, Ca(OH)2 powder, and NaOH powder are 50 parts, 40 parts, and 10 parts respectively) and 65 parts of soda lignin (density 0.45 g / cm³). 3 25 parts of modified nano-silica (with an average particle size of 35.6 μm, purity of 80 wt%, ash content of 7 wt%, water content of 8.2 wt%, and degradation temperature of 280 ℃) were mixed evenly to obtain a pre-mixed powder.

[0062] (4) Spray the pre-mixed liquid evenly onto the pre-mixed powder and dry it at 102℃ for 5 hours to obtain road asphalt anti-stripping agent A2.

[0063] Example 3

[0064] (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 50 °C to obtain a pre-mixed solution.

[0065] (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 20000 and heat at 106°C under reflux for 24 h. After the reaction is complete, filter, wash and dry at 100°C for 5 h to obtain modified nano silica for later use.

[0066] (3) Mix 100 parts of composite powder (of which CaCO3 powder, Ca(OH)2 powder, and NaOH powder are 50 parts, 40 parts, and 10 parts, respectively) and 60 parts of soda lignin (density 0.45 g / cm³). 3 20 parts of modified nano-silica (with an average particle size of 35.6 μm, purity of 80 wt%, ash content of 7 wt%, water content of 8.2 wt%, and degradation temperature of 260 ℃) were mixed evenly to obtain a pre-mixed powder.

[0067] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 105℃ for 4 hours to obtain road asphalt anti-stripping agent A3.

[0068] Example 4

[0069] (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.

[0070] (2) Mix 100 parts of nano silica and 6 parts of GPTMS in anhydrous ethanol and heat at 108°C under reflux for 12 h. After the reaction is completed, 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 100°C under reflux for 24 h. After the reaction is completed, filter, wash and dry at 100°C for 5 h to obtain modified nano silica for later use.

[0071] (3) Mix 100 parts of composite powder (of which CaCO3 powder, Ca(OH)2 powder, and NaOH powder are 50 parts, 40 parts, and 10 parts, respectively) and 60 parts of soda lignin (density 0.45 g / cm³). 3 20 parts of modified nano-silica (with an average particle size of 35.6 μm, purity of 80 wt%, ash content of 7 wt%, water content of 8.2 wt%, and degradation temperature of 250 °C) were mixed evenly to obtain a pre-mixed powder.

[0072] (4) Spray the pre-mixed liquid evenly onto the pre-mixed powder and dry it at 110℃ for 4 hours to obtain road asphalt anti-stripping agent A4.

[0073] Example 5

[0074] (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 hexadecyltrimethoxysilane, wherein hexadecyltrimethoxysilane accounts for 60 wt%) and stir evenly at 50 °C to obtain a pre-mixed solution.

[0075] (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 completed, add 3 parts of PEI with a molecular weight of 20,000, 2 parts of PEI with a molecular weight of 1,000 and 2 parts of PEI with a molecular weight of 70,000. Heat at 105°C under reflux for 24 h. After the reaction is completed, filter, wash and dry at 100°C for 5 h to obtain modified nano silica for later use.

[0076] (3) Mix 100 parts of composite powder (of which, CaCO3 powder, Ca(OH)2 powder, and NaOH powder are 45 parts, 40 parts, and 15 parts respectively) and 60 parts of soda lignin (density 0.45 g / cm³). 3 20 parts of modified nano-silica (with an average particle size of 35.6 μm, purity of 80 wt%, ash content of 7 wt%, water content of 8.2 wt%, and degradation temperature of 260 ℃) were mixed evenly to obtain a pre-mixed powder.

[0077] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 105℃ for 4 hours to obtain road asphalt anti-stripping agent A5.

[0078] Comparative Example 1

[0079] Same as Example 1, except that no soda lignin is added during the preparation process to obtain anti-stripping agent B1.

[0080] Comparative Example 2

[0081] Same as Example 1, except that nano-silica is directly used instead of modified nano-silica in the preparation process to obtain anti-stripping agent B2.

[0082] Comparative Example 3

[0083] 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.

[0084] Comparative Example 4

[0085] Same as Example 1, except that the mixture of N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane and dodecyltrimethoxysilane is not added during the preparation process to obtain anti-stripping agent B4.

[0086] Comparative Example 5

[0087] Same as Example 1, except that fatty alcohol polyoxyethylene ether phosphate is not added during the preparation process to obtain anti-stripping agent B5.

[0088] Comparative Example 6

[0089] 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.

[0090] According to the usage method, the asphalt mixture anti-stripping agents of Examples 1-5 and Comparative Examples 1-6 were incorporated into the mineral powder of the tailings aggregate asphalt mixture at a dosage of 40 wt% (40 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, the mineral powder was 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.

[0091] 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.

[0092] Table 1. Properties of the asphalt mixtures prepared in Examples 1-5 and Comparative Examples 1-6

[0093]

[0094] Continued from Table 1

[0095]

[0096] As can be seen from the results in Table 1, the tailings asphalt mixture prepared with the road asphalt anti-stripping agent prepared by 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. A road asphalt anti-stripping agent, characterized in that, By weight, it includes the following components: Composite powder: 100 parts; Fatty alcohol polyoxyethylene ether phosphate: 3~15 parts; Soda lignin: 40-80 parts; Organosilanes: 2-8 parts; Modified nano-silica: 15-50 parts; The modified nano-silica comprises the following components by weight: Nano silica: 100 parts; 3-Glycidyl etheroxypropylmethyldiethoxysilane: 3-8 parts; Polyethyleneimine: 3-10 parts.

2. The road asphalt anti-stripping agent according to claim 1, characterized in that, By weight, it includes the following components: Composite powder: 100 parts; Fatty alcohol polyoxyethylene ether phosphate: 3~15 parts; Soda lignin: 60-75 parts; Organosilanes: 2-5 parts; Modified nano-silica: 20-40 parts.

3. The road asphalt anti-stripping agent according to claim 1, characterized in that, The composite powder is a mixture of at least two of CaCO3 powder, Ca(OH)2 powder and NaOH powder; the average particle size of the composite powder is 20~50μm.

4. The road asphalt anti-stripping agent according to claim 1, characterized in that, The composite powder is a mixture of CaCO3 powder, Ca(OH)2 powder and NaOH powder; based on the total mass of the composite powder, CaCO3 powder accounts for 30% to 50% of the total mass, Ca(OH)2 powder accounts for 30% to 40% of the total mass, and NaOH powder accounts for 10% to 40% of the total mass.

5. The road 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.

6. The road asphalt anti-stripping agent according to claim 1, characterized in that, The soda lignin has the following properties: density of 0.3~0.5 g / cm³. 3 The average particle size is 25~40μm, the purity is not less than 70wt%, the ash content is not greater than 8wt%, the water content is not greater than 10wt%, and the degradation temperature is 200~500℃.

7. The road 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.

8. The road asphalt anti-stripping agent according to claim 7, 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.

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

10. A method for preparing a road asphalt anti-stripping agent according to any one of claims 1-9, characterized in that, The preparation method includes: (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution; (2) Preparation of modified nano-silica; (3) Mix the composite powder, soda lignin and modified nano silica evenly to obtain a pre-mixed powder; (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 the asphalt anti-stripping agent.

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

12. The preparation method according to claim 10, characterized in that, In step (2), the method for preparing modified nano-silica is as follows: Nano-silica was mixed with 3-glycidyl etheroxypropylmethyldiethoxysilane 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 modified nano-silica.

13. The preparation method according to claim 12, 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.

14. The preparation method according to claim 13, 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 95℃~110℃.

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

16. The preparation method according to claim 10, characterized in that, In step (4), the drying temperature is 95~110℃ and the drying time is 2~5h.

17. The application of the road asphalt anti-stripping agent according to any one of claims 1-9 or the road asphalt anti-stripping agent prepared according to any one of claims 10-16 in asphalt mixtures.

18. The application according to claim 17, characterized in that, The application includes: incorporating the road asphalt anti-stripping agent into the mineral powder of the tailings aggregate asphalt mixture, wherein the amount of road asphalt anti-stripping agent incorporated accounts for 30wt%~50wt% of the mineral powder mass, 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.

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