Road asphalt anti-stripping agent, method for preparing same and use thereof

Abstract

The application discloses a road asphalt anti-stripping agent and a preparation method and application thereof. The road asphalt anti-stripping agent comprises the following components in parts by weight: composite powder: 100 parts; fatty alcohol polyoxyethylene ether phosphate: 3-15 parts; organosilane: 2-8 parts; and modified biochar powder: 15-60 parts. The road asphalt anti-stripping agent can significantly improve the adhesion between tailing aggregate and asphalt and improve the water stability of tailing asphalt mixture.

Description

Technical Field

[0001] This invention belongs to the field of road asphalt, specifically relating 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 effectively, preventing water damage and 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 designed 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 making comprehensive use of tailings solid waste resources, has significant social and economic implications. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a road asphalt anti-stripping agent, its preparation method, and its application. This road asphalt anti-stripping agent can significantly 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] Organosilane: 2-8 parts, preferably 2-5 parts;

[0012] Modified biochar powder: 15-60 parts, preferably 25-50 parts.

[0013] 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 20–50 μm.

[0014] 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.

[0015] The fatty alcohol polyoxyethylene ether phosphate has the general formula RO(CH2CH2O). n PO3H2, where n is an integer from 3 to 9. The fatty alcohol ROH used in the synthesis of 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, cetyl alcohol, or one or more of these.

[0016] 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.

[0017] 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.

[0018] The long-chain organosilane is one or more of dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecylmethyldimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0019] The modified biochar powder comprises the following components by weight:

[0020] Biochar powder: 100 parts;

[0021] 3-Glycidyl etheroxypropylmethyldiethoxysilane (GPTMS): 3-8 parts, preferably 3-6 parts;

[0022] Polyethyleneimine (PEI): 3 to 10 parts, preferably 5 to 8 parts.

[0023] The biochar powder is prepared from traditional Chinese medicine residues.

[0024] Specifically, the biochar powder is prepared from traditional Chinese medicine residues through dehydration and drying, primary pulverization, anaerobic carbonization, secondary pulverization, and sieving.

[0025] The source of the herbal medicine residue is not particularly limited. Preferably, the herbal medicine residue, based on the dehydrated and dried dry matter, has a crude fiber content of 15% to 30% of the total mass. The herbal medicine residue, based on the dehydrated and dried dry matter, has an acid detergent fiber content of 25% to 50% of the total mass and a neutral detergent fiber content of 50% to 70% of the total mass. The herbal medicine residue, based on the dehydrated and dried dry matter, has a crude ash content of 5% to 10% of the total mass.

[0026] The biochar powder has an average particle size of 100–180 mesh, preferably 120–160 mesh. The moisture content of the biochar powder is not higher than 0.5% by mass.

[0027] The 3-glycidyl etheroxypropylmethyldiethoxysilane is a commercially available product.

[0028] The molecular weight of the polyethyleneimine is 1,000 to 70,000, preferably one or more of 1,000, 20,000, and 70,000.

[0029] A second aspect of the present invention provides a method for preparing the above-mentioned anti-stripping agent for road asphalt, comprising:

[0030] (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution;

[0031] (2) Preparation of modified biochar powder;

[0032] (3) Mix the composite powder and modified biochar powder evenly to obtain a pre-mixed powder;

[0033] (4) The premixed liquid obtained in step (1) is evenly sprayed onto the premixed powder obtained in step (3) and dried to obtain the road asphalt anti-stripping agent.

[0034] 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.

[0035] In step (1), the mixing temperature of the fatty alcohol polyoxyethylene ether phosphate and organosilane is 45-65°C.

[0036] In step (2), the method for preparing the modified biochar powder includes:

[0037] I. Preparation of biochar powder;

[0038] II. The prepared biochar powder 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 biochar powder.

[0039] In step I, the method for preparing the biochar powder includes:

[0040] a. Dehydrate, dry, and pulverize the residue of Chinese medicinal herbs in one step;

[0041] b. Perform anaerobic carbonization on the residue after step a.

[0042] c. Cool the residue after carbonization in step b, pulverize it again, and sieve it to obtain biochar powder.

[0043] Step a can be carried out in a dehydration and drying machine for medicinal residues. The first pulverization involves pulverizing the medicinal residues to 50-80 mesh. The dehydration and drying conditions are not particularly limited, but generally, the moisture content of the medicinal residues after step a should not exceed 20%.

[0044] The anaerobic carbonization described in step b can be carried out in a continuous slag carbonization furnace. The temperature of the anaerobic carbonization is 400-700℃, the heating rate is 8-15℃ / min, the carbonization time is 30-60min, and the anaerobic carbonization process is carried out in an atmosphere of N2 and / or inert gas.

[0045] In step c, cooling simply means cooling to room temperature. After secondary pulverization and sieving, the resulting biochar powder has a mesh size of 120–160 mesh.

[0046] In step c, the cooling, secondary crushing, and sieving must be carried out in a dry environment to ensure that the moisture content of the obtained biochar powder does not exceed 0.5 wt%.

[0047] In step II, the amount of anhydrous ethanol used should be sufficient to completely submerge and mix the reactants, and to allow for adequate reflux.

[0048] In step II, the reaction temperature of the first heating reflux is 90℃~130℃, preferably 100℃~115℃, and the reaction time is 12~18h.

[0049] In step II, the reaction temperature of the second heating reflux is 90℃~120℃, preferably 95℃~110℃, and the reaction time is 20~24h.

[0050] The reaction temperature of the first heating reflux is preferably 3 to 10°C higher than that of the second heating reflux.

[0051] In step II, the filtration and washing can be carried out using conventional methods in the art.

[0052] In step II, the drying temperature is 80℃~120℃ and the time is 0.5~5h, preferably 3~5h.

[0053] In step (4), the drying temperature is 95-110℃ and the drying time is 2-5h.

[0054] The third aspect of this invention discloses the application of the above-mentioned road asphalt anti-stripping agent in asphalt mixtures.

[0055] The asphalt mixture is a tailings aggregate asphalt mixture.

[0056] 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.

[0057] Compared with the prior art, the present invention has the following advantages:

[0058] (1) The road 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 of the aggregate surface. 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 aggregate surface, and the other end is entangled and cross-linked with the asphalt polymer, 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.

[0059] (2) The biochar powder in this invention has abundant oxygen-containing functional groups (such as carboxyl, carbonyl, phenol, lactone and quinone, etc.), which can be functionalized by grafting modification. The modified biochar powder can not only improve the pH buffering capacity of the anti-stripping agent, but also tightly adsorb and bind with the aggregate. The branched active groups introduced by modification and the active groups of biochar itself can also react with hydroxyl, carboxyl and unsaturated bonds in asphalt, tightly bind the asphalt and aggregate interface, and improve the anti-stripping performance of asphalt mixture. In addition, the addition of modified biochar can greatly improve the rutting resistance of asphalt binder and improve the pavement performance.

[0060] (3) The modified biochar powder in this invention comes from Chinese medicine residues. Applying it to road construction avoids carbon emissions caused by the combustion of Chinese medicine residues, thus having a good environmental protection effect. On the other hand, Chinese medicine residues are widely available, which improves the anti-stripping performance of the road surface while reducing the road construction cost, thus having a certain cost advantage.

[0061] (4) 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 requirements of road pavement 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

[0062] 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. The wt% mentioned refers to the mass fraction, and the number of parts mentioned refers to the number of parts by weight.

[0063] In this invention, the contents of crude fiber, acid detergent fiber, and neutral detergent fiber in the biochar powder were determined according to the methods of GB / T 6434-2006, NY / T 1459-2007, and GB / T 20806-2006, respectively, using an FT12 fully automatic fiber analyzer. The crude ash content was determined according to the method described in *Zhang LY. Technologies of Feed Analysis and Feed Quality Detection, 2nd Ed. Beijing: Chinese Agricultural University Press, 2003.*

[0064] 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.

[0065] 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.

[0066] Example 1

[0067] (1) Mix 7 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.

[0068] (2) Preparation of biochar powder: The Chinese herbal medicine residue (containing 18.25% crude fiber, 26.71% acid detergent fiber, 54.37% neutral detergent fiber, and 8.66% crude ash) was dehydrated and dried using a residue dehydrator. After a first crushing process, a residue with a particle size of 50-80 mesh and a moisture content of 16.4% was obtained. The pre-treated residue was then subjected to anaerobic carbonization in a continuous residue carbonization furnace at a temperature of 600℃, a heating rate of 15℃ / min, and a carbonization time of 50 min, all within an N2 atmosphere. The carbonized residue was cooled and then crushed a second time to obtain biochar powder with a particle size of 120-160 mesh. The moisture content of the biochar powder was tested to be 0.37%.

[0069] 100 parts of the above biochar powder and 6 parts of 3-glycidyl etheroxypropylmethyldiethoxysilane (GPTMS) were mixed in anhydrous ethanol and refluxed at 105°C for 16 h. After the reaction was completed, 7 parts of polyethyleneimine (PEI) with a molecular weight of 20,000 were added and refluxed at 102°C for 22 h. After the reaction was completed, the mixture was filtered, washed, and dried at 105°C for 5 h to obtain modified biochar powder for later use.

[0070] (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 20 parts of modified biochar powder evenly to obtain pre-mixed powder.

[0071] (4) Spray the pre-mixed liquid evenly onto the pre-mixed powder and dry it at 105℃ for 3 hours to obtain road asphalt anti-stripping agent A1.

[0072] Example 2

[0073] (1) Mix 5 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.

[0074] (2) 100 parts of biochar powder (preparation method is the same as in Example 1) and 5 parts of GPTMS were mixed in anhydrous ethanol and heated under reflux at 106°C for 12 h. After the reaction was completed, 6 parts of PEI with a molecular weight of 20000 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 modified biochar powder for later use.

[0075] (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 25 parts of modified biochar powder evenly to obtain pre-mixed powder.

[0076] (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.

[0077] Example 3

[0078] (1) Mix 8 parts of fatty alcohol polyoxyethylene ether phosphate and 5 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.

[0079] (2) 100 parts of biochar powder (preparation method is the same as in Example 1) and 6 parts of GPTMS were mixed in anhydrous ethanol and heated under reflux at 110°C for 12 h. After the reaction was completed, 7 parts of PEI with a molecular weight of 20000 were added and heated under reflux at 106°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 biochar powder for later use.

[0080] (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 20 parts of modified biochar powder evenly to obtain pre-mixed powder.

[0081] (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.

[0082] Example 4

[0083] (1) Mix 9 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.

[0084] (2) Preparation of biochar powder: The Chinese herbal medicine residue (containing 19.31% crude fiber, 25.94% acid detergent fiber, 56.72% neutral detergent fiber, and 8.33% crude ash) was dehydrated and dried using a residue dehydrator. After a first crushing process, a Chinese herbal medicine residue with a particle size of 50-80 mesh and a moisture content of 16.1% was obtained. The pre-treated residue was then subjected to anaerobic carbonization in a continuous residue carbonization furnace at a temperature of 620℃, a heating rate of 15℃ / min, and a carbonization time of 40 min, all within an N2 atmosphere. The carbonized residue was cooled and then crushed a second time to obtain biochar powder with a particle size of 120-160 mesh. The moisture content of this biochar powder was tested to be 0.32%.

[0085] 100 parts of biochar powder and 6 parts of GPTMS were mixed in anhydrous ethanol and heated under reflux at 108°C for 12 h. After the reaction was completed, 3 parts of PEI with a molecular weight of 20,000 and 4 parts of PEI with a molecular weight of 70,000 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 modified biochar powder for later use.

[0086] (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 20 parts of modified biochar powder evenly to obtain pre-mixed powder.

[0087] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 100°C for 4 hours to obtain road asphalt anti-stripping agent A4.

[0088] Example 5

[0089] (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.

[0090] (2) 100 parts of biochar powder (preparation method is the same as in Example 4) and 6 parts of GPTMS were mixed in anhydrous ethanol and heated under reflux at 110°C for 12 h. After the reaction was completed, 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 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 biochar powder for later use.

[0091] (3) Mix 100 parts of composite powder (of which 45 parts of CaCO3 powder, 35 parts of Ca(OH)2 powder and 20 parts of NaOH powder and 20 parts of modified biochar powder evenly to obtain pre-mixed powder.

[0092] (4) Spray the premixed liquid evenly onto the premixed powder and dry it at 110℃ for 4 hours to obtain road asphalt anti-stripping agent A5.

[0093] Comparative Example 1

[0094] Same as Example 1, except that modified biochar powder is not added during the preparation process to obtain anti-stripping agent B1.

[0095] Comparative Example 2

[0096] Same as Example 1, except that biochar powder is directly used instead of modified biochar powder in the preparation process to obtain anti-stripping agent B2.

[0097] Comparative Example 3

[0098] Same as Example 1, except that the preparation method of the modified biochar powder is as follows: 6 parts of biomimetic material methacrylamide dopamine and 100 parts of biochar powder and 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 the modified biochar powder composite modifier for later use. Finally, the exfoliating agent B3 is obtained.

[0099] Comparative Example 4

[0100] 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.

[0101] Comparative Example 5

[0102] Same as Example 1, except that fatty alcohol polyoxyethylene ether phosphate is not added during the preparation process to obtain anti-stripping agent B5.

[0103] Comparative Example 6

[0104] 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.

[0105] According to the usage method, the 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.

[0106] 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.

[0107] Table 1. Properties of the asphalt mixtures prepared in Examples 1-5 and Comparative Examples 1-6

[0108]

[0109] Continued from Table 1

[0110]

[0111] 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, The road asphalt anti-stripping agent comprises the following components by weight: Composite powder: 100 parts; Fatty alcohol polyoxyethylene ether phosphate: 3-15 parts, preferably 5-10 parts; Organosilane: 2-8 parts, preferably 2-5 parts; Modified biochar powder: 15-60 parts, preferably 25-50 parts.

2. 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 20–50 μm. Preferably, the composite powder is a mixture of CaCO3 powder, Ca(OH)2 powder and NaOH powder, wherein, 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.

3. 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). n PO3H2, where n is an integer from 3 to 9; wherein, the fatty alcohol ROH used in the synthesis of fatty alcohol polyoxyethylene ether phosphate is a normal fatty alcohol and / or an isomeric fatty alcohol, selected from C8-18 alcohols, such as one or more of isooctanol, lauryl alcohol, isodecyl alcohol, and cetyl alcohol.

4. 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; And / or, 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 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.

5. The road asphalt anti-stripping agent according to claim 1, characterized in that, The modified biochar powder comprises the following components by weight: Biochar powder: 100 parts; 3-Glycidyl etheroxypropylmethyldiethoxysilane: 3-8 parts, preferably 3-6 parts; Polyethyleneimine: 3 to 10 parts, preferably 5 to 8 parts.

6. The road asphalt anti-stripping agent according to claim 5, characterized in that, The biochar powder is prepared from traditional Chinese medicine residues; specifically, the biochar powder is prepared from traditional Chinese medicine residues through dehydration and drying, primary pulverization, anaerobic carbonization, secondary pulverization, and sieving.

7. The road asphalt anti-stripping agent according to claim 6, characterized in that, The herbal residue, based on the dehydrated and dried dry matter, has a crude fiber content of 15% to 30% of the total mass; the herbal residue, based on the dehydrated and dried dry matter, has an acid detergent fiber content of 25% to 50% of the total mass and a neutral detergent fiber content of 50% to 70% of the total mass; the herbal residue, based on the dehydrated and dried dry matter, has a crude ash content of 5% to 10% of the total mass.

8. The road asphalt anti-stripping agent according to claim 5, characterized in that, The average particle size of the biochar powder is 100-180 mesh, preferably 120-160 mesh; the moisture content of the biochar powder is not higher than 0.5% by mass.

9. The road asphalt anti-stripping agent according to claim 5, characterized in that, The molecular weight of the polyethyleneimine is 1,000 to 70,000.

10. A method for preparing the road asphalt anti-stripping agent according to any one of claims 1-9, comprising: (1) Mix fatty alcohol polyoxyethylene ether phosphate and organosilane evenly to prepare a premixed solution; (2) Preparation of modified biochar powder; (3) Mix the composite powder and modified biochar powder evenly to obtain a pre-mixed powder; (4) The premixed liquid obtained in step (1) is evenly sprayed onto the premixed powder obtained in step (3) and dried to obtain the road 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°C.

12. The preparation method according to claim 10, characterized in that, In step (2), the method for preparing the modified biochar powder includes: I. Preparation of biochar powder; II. The prepared biochar powder 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 biochar powder.

13. The preparation method according to claim 12, characterized in that, In step I, the method for preparing the biochar powder includes: a. Dehydrate, dry, and pulverize the residue of Chinese medicinal herbs in one step; b. Perform anaerobic carbonization on the residue after step a. c. Cool the residue after carbonization in step b, pulverize it again, and sieve it to obtain biochar powder.

14. The preparation method according to claim 13, characterized in that, In step a, the first pulverization refers to pulverizing the Chinese herbal medicine residue to 50-80 mesh; In step b, the temperature of the anaerobic carbonization is 400-700℃, the heating rate is 8-15℃ / min, the carbonization time is 30-60min, and the anaerobic carbonization process is carried out in an atmosphere of N2 and / or inert gas. In step c, after secondary crushing and sieving, the resulting biochar powder has a mesh size of 120-160.

15. The preparation method according to claim 12, characterized in that, In step II, the reaction temperature of the first heating reflux is 90℃~130℃, preferably 100℃~115℃, and the reaction time is 12~18h; And / or, in step II, the reaction temperature of the second heating reflux is 90°C to 120°C, preferably 95°C to 110°C, and the reaction time is 20 to 24 hours; And / or, the reaction temperature of the first heating reflux is 3 to 10°C 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 by any one of claims 10-16 in asphalt mixtures.

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