A rutting-resistant low-carbon asphalt mixture and its preparation method

Abstract

The application discloses a kind of anti-rutting low-carbon asphalt mixture and preparation method thereof, belong to bitumen processing technical field, for solving the technical problem that the rutting resistance and high temperature resistance of asphalt mixture in prior art need to be further improved, specifically includes the following steps: matrix asphalt is placed in stirrer, heated to 150-160 DEG C, stir 5-10min, add dicumyl peroxide and maleic anhydride, heat preservation reaction 1-2h, post-treatment obtains activated asphalt;The application is mixed with activated asphalt, modified epoxy resin, amino modified regenerated fiber, curing agent, recycled stone, steel slag powder and modified rubber powder, to obtain low-carbon asphalt mixture, not only improve the rutting resistance and high temperature resistance of asphalt mixture, but also improve its mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of asphalt processing technology, specifically to a rutting-resistant low-carbon asphalt mixture and its preparation method. Background Technology

[0002] With the advancement of the "dual-carbon strategy" globally, the demand for environmentally friendly materials in the road engineering field continues to grow. In recent years, low-carbon asphalt mixtures have gradually gained attention as a material system that balances environmental protection and performance. Research directions mainly include warm mix technology, bio-based asphalt substitutes, efficient utilization of recycled materials, and mix design optimization to minimize carbon footprint.

[0003] Among them, recycled materials mainly include industrial solid waste such as waste asphalt mixtures, waste rubber, waste plastics, fly ash and steel slag. These materials can not only partially or completely replace traditional asphalt binders or mineral materials, significantly reducing the use of raw materials and carbon emissions, but also give the mixture good high-temperature stability and environmental adaptability.

[0004] However, while using recycled materials to prepare asphalt mixtures has significant advantages in terms of environmental protection and resource recycling, it generally has shortcomings in rutting resistance, mechanical properties, and high-temperature stability, which limits its widespread application in heavy-duty roads and high-temperature areas.

[0005] In existing technologies, the main reason for the insufficient performance of asphalt mixtures prepared using recycled materials is that the interfacial compatibility between recycled materials and new asphalt is poor, forming weak interfacial regions that weaken the overall structural stability and shear resistance of the mixture. Furthermore, although some recycled polymers have a certain stiffness, they are prone to forming local stress concentrations in the mixture, affecting its mechanical continuity and overall load-bearing capacity. In addition, for recycled rubber powder and recycled polyester, the vulcanization bonds in recycled rubber powder form a highly cross-linked structure, making the rubber hard and lacking fluidity. The surface of recycled polyester fibers has a weakly polar structure, which has poor compatibility with the matrix and makes it difficult to reinforce the asphalt mixture. Summary of the Invention

[0006] The purpose of this invention is to provide a rutting-resistant low-carbon asphalt mixture and its preparation method, which solves the technical problem that the rutting resistance and high-temperature resistance of asphalt mixtures in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a method for preparing a rutting-resistant low-carbon asphalt mixture, comprising the following steps:

[0008] S1. Place the base asphalt in a mixer, heat it to 150-160℃, stir for 5-10 minutes, add dicumyl peroxide and maleic anhydride, keep it at the temperature for 1-2 hours, and then treat it to obtain activated asphalt.

[0009] The reaction principle for preparing activated asphalt is as follows:

[0010] During the reaction, under the action of high temperature and catalyst, the conjugated diene in the base asphalt undergoes a Diels-Alder reaction with maleic anhydride. In the post-treatment step, a small amount of deionized water is added, and the anhydride is hydrolyzed into carboxyl groups to obtain activated asphalt.

[0011] S2. Add activated asphalt, amino-modified recycled fiber, curing agent, recycled stone, steel slag powder and modified rubber powder to a mixer, heat to 150-160℃, stir for 5-10 minutes to obtain a mixed slurry;

[0012] S3. Add the modified epoxy resin to the mixer and stir for 1-2 minutes. Add the mixed slurry and stir for 15-30 minutes to obtain the low-carbon asphalt mixture.

[0013] The reaction principle for preparing low-carbon asphalt mixtures is as follows:

[0014] During the reaction, the carboxylic acid groups of the activated asphalt, the amino groups of the amino-modified regenerated fibers, the diamino groups of the curing agent, and the oxygen-containing functional groups of the modified rubber powder all participate in the curing of the modified epoxy resin, resulting in a low-carbon asphalt mixture.

[0015] Further, in step S1, the ratio of the base asphalt, dicumyl peroxide, and maleic anhydride is 15-20g:0.5-1g:20-22g. The post-treatment step includes: after the reaction is completed, adding 5-10mL of deionized water to the reaction solution, stirring for 1-5min, and then transferring it to an oven at 90-100℃ for drying for 20-30min to obtain activated asphalt; in step S2, the ratio of the activated asphalt, amino-modified recycled fiber, curing agent, recycled stone, steel slag powder, and modified rubber powder is 50-70g:1-2g:1-2g:500-700g:400-600g:2-4g, and the curing agent is 4,4'-diaminodiphenylmethane; in step S3, the ratio of the modified epoxy resin and the mixed slurry is 5-6g:65-75g.

[0016] Furthermore, the amino-modified regenerated fiber is prepared by the following steps:

[0017] A1. After crushing the waste polyester bottle flakes, add them to a twin-screw melt extruder, melt extrude, stretch, and cut them to obtain recycled polyester fibers.

[0018] A2. Plasma treatment is performed on recycled polyester fibers to obtain pretreated recycled fibers;

[0019] The reaction principle for preparing pretreated regenerated fibers is as follows:

[0020] During the reaction, the active species oxygen ions in the plasma react with the surface of the recycled polyester fiber, introducing oxygen-containing polar groups to obtain pretreated recycled fiber.

[0021] A3. Place the pretreated regenerated fiber, deionized water, ethanol and KH-550 in a reaction vessel, heat to 30-50℃, keep the temperature for 2-4 hours, and then treat to obtain amino-modified regenerated fiber.

[0022] The reaction principle for preparing amino-modified regenerated fibers is as follows:

[0023] During the reaction, KH-550 hydrolyzes into silanol, which then undergoes a condensation reaction with the hydroxyl groups of the pretreated regenerated fiber to obtain amino-modified regenerated fiber.

[0024] Furthermore, in step A1, the length of the recycled polyester fiber is 4-6 mm, the temperature of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port is 270℃, 270℃, 275℃, 275℃, 285℃, 285℃, 295℃, and 295℃ respectively, the main speed of the twin-screw extruder is 80-120 rpm, the pressure is 100-150 bar, and the draw ratio is 4-5 times.

[0025] Furthermore, in step A2, the plasma treatment step includes: placing the recycled polyester fiber in a plasma chamber, evacuating it to a vacuum state, introducing oxygen, setting the discharge power to 50-150W, and treating it for 1-5 minutes to obtain pretreated recycled fiber.

[0026] Furthermore, in step A3, the ratio of the amount of pretreated regenerated fiber, deionized water, ethanol and KH-550 is 4-6g:5-8mL:50-100mL:0.5-1g. The post-treatment steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed 1-2 times with deionized water and ethanol, transferred to an oven at 50-60℃, and dried to constant weight to obtain amino-modified regenerated fiber.

[0027] Furthermore, the modified rubber powder is prepared by placing waste rubber powder, 2,2'-dibenzoylaminodiphenyl disulfide, zinc oxide and naphthenic oil in a reaction vessel, heating to 155-165℃, stirring for 1.5-2.5h, and then processing to obtain the modified rubber powder.

[0028] The reaction principle for preparing modified rubber powder is as follows:

[0029] During the reaction, naphthenic oil penetrates into the rubber molecular chains, weakening the cross-linking network, increasing the free volume, and promoting catalyst diffusion. 2,2'-Dibenzoylaminodiphenyl disulfide decomposes under high temperature and catalytic conditions, generating two benzoylamino sulfur free radicals. These sulfur free radicals attack the α-H in the waste rubber powder molecular chains, generating rubber macromolecular free radicals and thiols. The rubber macromolecular free radicals react with the thiols, breaking the SS cross-linking bonds to achieve desulfurization, generating a small amount of carboxylic acid and oxygen-containing functional groups such as hydroxyl groups, thus obtaining modified rubber powder.

[0030] Furthermore, the ratio of waste rubber powder, 2,2'-dibenzoylaminodiphenyl disulfide, zinc oxide, and naphthenic oil is 4-8g:0.1-0.2g:0.15-0.3g:6-12g, the stirring rate is 450rpm, and the post-processing steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed 1-2 times with deionized water, transferred to an oven at 50-60℃, and dried to constant weight to obtain modified rubber powder.

[0031] Furthermore, the modified epoxy resin is prepared by the following steps:

[0032] B1. Place 1,4-phenyldiboronic acid, 1,2,5-pentanetriol and tetrahydrofuran in a reaction vessel, add anhydrous magnesium sulfate, react at room temperature for 20-24 h, and then perform post-treatment to obtain intermediate I.

[0033] The reaction formula for the preparation of intermediate I is as follows:

[0034]

[0035] The reaction principle for the preparation of intermediate I is as follows:

[0036] During the reaction, the two borate groups of 1,4-phenyldiboronic acid can undergo a condensation reaction with the hydroxyl groups of 1,2,5-pentanetriol, removing water molecules to form a borate ester bond. Since there are two adjacent hydroxyl groups in the pentanetriol molecule, a five-membered stable borate ester structure may be generated through intramolecular reaction, yielding intermediate I. The mass spectrometry data of intermediate I are as follows: m / z: 620.35 (100.0%), 619.35 (76.7%), 618.35 (28.6%), 621.35 (25.4%), 619.36 (9.0%), 622.35 (5.3%), 617.36 (4.8%), 621.36 (3.7%), 620.36 (2.4%), 618.36 (1.4%), 622.36 (1.1%).

[0037] B2. Place intermediate I, polytetrahydrofuran and N,N-dimethylformamide in a reaction vessel under nitrogen atmosphere protection, stir for 1-5 min, add dibutyltin dilaurate and a calculated amount of isophorone diisocyanate, heat to 95-105℃, keep the reaction at this temperature for 1-2 h to obtain intermediate II.

[0038] The reaction formula for the preparation of intermediate II is as follows:

[0039]

[0040] In the formula: , .

[0041] The reaction principle for the preparation of intermediate II is as follows:

[0042] During the reaction, under the action of a catalyst, intermediate I and the two terminal hydroxyl groups of polytetrahydrofuran undergo a nucleophilic reaction with isophorone diisocyanate. By controlling the amount of isophorone diisocyanate added, intermediate II with isophorone diisocyanate end capping is obtained.

[0043] B3. Place intermediate II and bisphenol A type epoxy resin in a reaction vessel under nitrogen atmosphere protection, add dibutyltin dilaurate, heat to 80-90℃, keep the temperature for 2-4 hours, and then perform post-treatment to obtain modified epoxy resin.

[0044] The preparation reaction formula for modified epoxy resin is as follows:

[0045]

[0046] The preparation reaction principle of modified epoxy resin is as follows:

[0047] During the reaction, the terminal isocyanate group of intermediate II undergoes a nucleophilic reaction with the hydroxyl group in bisphenol A type epoxy resin to obtain modified epoxy resin.

[0048] Further, in step B1, the ratio of 1,4-phenyldiboronic acid, 1,2,5-pentanetriol, tetrahydrofuran, and anhydrous magnesium sulfate is 2-4 g: 6-8 g: 100-120 mL: 10-12 g. The post-processing step includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, and the filtrate is transferred to a rotary evaporator at a temperature of 80-90°C and evaporated until no liquid is collected, to obtain intermediate I; in step B2, the ratio of intermediate I, polytetrahydrofuran, N,N-dimethylformamide, and dibutyltin dilaurate is... The ratio of intermediate I to polytetrahydrofuran is 1-2g:7-10g:120-150mL:0.2-0.5g. In the reaction, isophorone diisocyanate is 0.55 times the molar amount of hydroxyl groups in the reaction system, and the weight ratio of intermediate I to polytetrahydrofuran is 1-2:7-10. In step B3, the ratio of intermediate II, bisphenol A epoxy resin, and dibutyltin dilaurate is 5-7g:6-10g:0.5-1g. The post-treatment step includes: after the reaction is completed, heating to 150-160℃ and distilling under reduced pressure until no liquid is collected to obtain modified epoxy resin.

[0049] The present invention also provides a rutting-resistant low-carbon asphalt mixture, which is prepared by the above-described method for preparing a rutting-resistant low-carbon asphalt mixture.

[0050] The present invention has the following beneficial effects:

[0051] 1. This invention involves preparing intermediate I containing borate ester groups, further preparing intermediate II containing borate ester groups using isophorone diisocyanate as the hard segment and polytetrahydrofuran as the soft segment, chemically bonding intermediate II with bisphenol A type epoxy resin to obtain a modified epoxy resin with self-healing properties, obtaining recycled polyester fibers through melt spinning of waste polyester bottle flakes, further modifying the recycled polyester fibers with plasma treatment and silane coupling agent to obtain amino-modified recycled fibers, obtaining modified rubber powder with oxygen-containing functional groups through catalytic desulfurization treatment of waste rubber powder, obtaining activated asphalt by DA reaction modification of matrix asphalt with maleic anhydride, and further mixing the activated asphalt, modified epoxy resin, amino-modified recycled fibers, curing agent, recycled stone, steel slag powder, and modified rubber powder to obtain low-carbon asphalt. This invention relates to a process where recycled polyester fibers are obtained by melt spinning waste polyester bottle flakes. Further plasma treatment and silane coupling agent modification of the recycled polyester fibers yield amino-modified recycled fibers. Plasma treatment introduces oxygen-containing functional groups such as carboxyl, hydroxyl, and epoxy groups onto the surface of the recycled polyester fibers, enhancing their reactivity. This, combined with the amino functional layer modified by the silane coupling agent, significantly strengthens the interfacial adhesion and stability between the fibers and the asphalt mixture, thereby significantly improving the asphalt mixture's shear resistance and crack resistance. Furthermore, the chopped polyester fibers are distributed in a multidirectional network structure within the mixture, limiting the micro-deformation of the asphalt mixture and improving its rutting resistance. Using waste polyester bottle flakes as raw material to produce recycled polyester fibers not only reduces manufacturing costs but also significantly reduces plastic waste, embodying a green and environmentally friendly concept.

[0052] 2. This invention also prepares intermediate I containing borate ester groups, and further prepares intermediate II containing borate ester groups using isophorone diisocyanate as the hard segment and polytetrahydrofuran as the soft segment. Intermediate II is then chemically bonded to bisphenol A type epoxy resin to obtain a modified epoxy resin with self-healing properties. When microcracks appear on the asphalt surface, the modified epoxy resin can automatically repair the cracks through a self-healing mechanism, preventing crack propagation and thus extending the service life of the pavement. The epoxy resin has strong chemical stability, and through interaction with activated asphalt, amino-modified regenerated fibers, curing agents, and modified rubber powder, it forms a more stable, robust, and elastic material network structure, which can effectively improve the mechanical properties of asphalt and slow down the aging process. The thermal cracking and thermal expansion issues in high-temperature environments further improve the rutting resistance and high-temperature resistance of asphalt mixtures. Simultaneously, in the asphalt mixture preparation process, besides the curing agent 4,4'-diaminodiphenylmethane, activated asphalt, amino-modified regenerated fibers, curing agents, and modified rubber powder can all participate in promoting the curing process of modified epoxy resin, reducing the curing time and temperature required for the modified epoxy resin, and improving the mechanical properties of the cured asphalt mixture. Grafting maleic anhydride into the base asphalt provides more reaction sites on the base asphalt surface, enhancing the interfacial adhesion between the base asphalt and modified rubber powder, amino-modified regenerated fibers, and modified epoxy resin, further improving the mechanical properties and high-temperature resistance of the asphalt mixture.

[0053] 3. This invention also catalytically depolymerizes waste rubber powder, breaking disulfide bonds and introducing oxygen-containing functional groups to obtain modified rubber powder. After catalytic depolymerization and disulfide bond breaking, the molecular weight of the waste rubber powder decreases and its fluidity increases. Simultaneously, the introduced oxygen-containing functional groups can chemically bond with the modified epoxy resin in asphalt, forming a three-dimensional elastic cross-linked network. This significantly improves the compatibility of the matrix in asphalt mixtures, avoiding phase separation problems. Under high-temperature environments, it can effectively inhibit asphalt flow and plastic deformation, thereby improving rutting resistance. Furthermore, under repeated cyclic loading, road materials are prone to microcracks that gradually propagate and lead to fatigue failure. Due to its good elasticity and flexibility, the rubber powder acts as a stress buffer and energy absorber in the composite system, alleviating stress concentration at the microcrack tips and thus slowing down crack propagation. This elastic regulation effect significantly improves the mechanical properties of asphalt mixtures. At the same time, the reuse of waste rubber powder reduces solid waste pollution, and the energy consumption of the catalytic depolymerization process is lower than that of traditional recycling processes, improving the environmental friendliness of asphalt mixture preparation. Detailed Implementation

[0054] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The matrix asphalt used in this invention was purchased from Hebei Hankai Energy Technology Development Co., Ltd., model HK-zw, ​​with a softening point of 70-90℃, and product name medium-temperature asphalt block;

[0056] The polytetrahydrofuran used in this invention was purchased from Shanghai Hongzhuang Chemical Technology Co., Ltd., with a molecular weight of 1000 and the brand name Hongzhuang.

[0057] The bisphenol A type epoxy resin used in this invention was purchased from Shanghai Qilong Biotechnology Co., Ltd., with the grade E-51 and an epoxy equivalent of 185-196.

[0058] The waste rubber powder used in this invention was purchased from Lingshou County Bohan Mineral Products Co., Ltd., with a density of 2.45 g / cm³ and a particle size of 40-80 mesh.

[0059] The recycled stone used in this invention was purchased from Wuhan Xinjunxi Haifa Building Materials Co., Ltd., with a specific gravity of 1550 kg / m³. 3 The particle size is 5-15mm;

[0060] The steel slag powder used in this invention was purchased from Lingshou County Chengwang Mineral Products Co., Ltd., with a particle size of 1-3mm and a grade of Grade 1.

[0061] The naphthenic oil used in this invention was purchased from Zibo Guangyi Petrochemical Co., Ltd., and has a density of 1.04-1.08 g / cm³. 3 The product name is aromatic oil;

[0062] The waste polyester bottle flakes used in this invention were purchased from Jiangsu Guli New Material Co., Ltd., with the brand name CZ-318 and the Chinese name being polyethylene terephthalate.

[0063] The KH-550 used in this invention was purchased from Shandong Yuanjin New Materials Co., Ltd., and its chemical name is γ-aminopropyltriethoxysilane with a density of 0.942 g / cm³. 3 .

[0064] Example 1

[0065] This embodiment provides a method for preparing a modified epoxy resin for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0066] Step ①: Preparation of intermediate I

[0067] Weigh 20g of 1,4-phenyldiboronic acid, 60g of 1,2,5-pentanetriol and 1000mL of tetrahydrofuran and place them in a reaction vessel. Add 100g of anhydrous magnesium sulfate and react at room temperature for 20h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filtrate to a rotary evaporator at 80℃. Evaporate until no liquid is collected to obtain intermediate I.

[0068] Step ②: Preparation of intermediate II

[0069] Weigh out 10g of intermediate I, 70g of polytetrahydrofuran, and 1200mL of N,N-dimethylformamide and place them in a reaction vessel under a nitrogen atmosphere. Stir for 1 min, add 2g of dibutyltin dilaurate, and calculate the amount of isophorone diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in intermediate I and polytetrahydrofuran. Add it to the reaction vessel, heat to 95℃, and keep the reaction at this temperature for 1 h to obtain intermediate II.

[0070] Step 3: Preparation of modified epoxy resin

[0071] Weigh 50g of intermediate II and 60g of bisphenol A type epoxy resin and place them in a reaction vessel under nitrogen atmosphere protection. Add 5g of dibutyltin dilaurate, heat to 80℃, and keep the temperature for 2 hours. After the reaction is completed, heat to 150℃ and distill under reduced pressure until no liquid is collected to obtain modified epoxy resin.

[0072] Example 2

[0073] This embodiment provides a method for preparing a modified epoxy resin for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0074] Step ①: Preparation of intermediate I

[0075] Weigh out 30g of 1,4-phenyldiboronic acid, 70g of 1,2,5-pentanetriol and 1100mL of tetrahydrofuran and place them in a reaction vessel. Add 110g of anhydrous magnesium sulfate and react at room temperature for 22h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filtrate to a rotary evaporator at 85℃. Rotary evaporate until no liquid is collected to obtain intermediate I.

[0076] Step ②: Preparation of intermediate II

[0077] 20g of intermediate I, 85g of polytetrahydrofuran, and 1350mL of N,N-dimethylformamide were placed in a reaction vessel under a nitrogen atmosphere and stirred for 3 minutes. 3.5g of dibutyltin dilaurate was added. The amount of isophorone diisocyanate to be added was calculated as 0.55 times the total molar amount of hydroxyl groups in intermediate I and polytetrahydrofuran, and added to the reaction vessel. The temperature was raised to 100℃ and the reaction was maintained for 1.5h to obtain intermediate II.

[0078] Step 3: Preparation of modified epoxy resin

[0079] Weigh 60g of intermediate II and 80g of bisphenol A type epoxy resin and place them in a reaction vessel under nitrogen atmosphere protection. Add 3g of dibutyltin dilaurate, heat to 85℃, and keep the temperature for 3h. After the reaction is completed, heat to 155℃ and distill under reduced pressure until no liquid is collected to obtain modified epoxy resin.

[0080] Example 3

[0081] This embodiment provides a method for preparing a modified epoxy resin for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0082] Step ①: Preparation of intermediate I

[0083] Weigh out 40g of 1,4-phenyldiboronic acid, 80g of 1,2,5-pentanetriol and 1200mL of tetrahydrofuran and place them in a reaction vessel. Add 120g of anhydrous magnesium sulfate and react at room temperature for 24h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filtrate to a rotary evaporator at 90℃. Evaporate until no liquid is collected to obtain intermediate I.

[0084] Step ②: Preparation of intermediate II

[0085] 20g of intermediate I, 100g of polytetrahydrofuran, and 1500mL of N,N-dimethylformamide were placed in a reaction vessel under a nitrogen atmosphere and stirred for 5 minutes. 5g of dibutyltin dilaurate was added. The amount of isophorone diisocyanate added was calculated as 0.55 times the total molar amount of hydroxyl groups in intermediate I and polytetrahydrofuran, and added to the reaction vessel. The temperature was raised to 105℃ and the reaction was maintained for 2 hours to obtain intermediate II.

[0086] Step 3: Preparation of modified epoxy resin

[0087] Weigh 70g of intermediate II and 100g of bisphenol A type epoxy resin and place them in a reaction vessel under nitrogen atmosphere protection. Add 10g of dibutyltin dilaurate, heat to 90℃, and keep the temperature for 4h. After the reaction is completed, heat to 160℃ and distill under reduced pressure until no liquid is collected to obtain modified epoxy resin.

[0088] Example 4

[0089] This embodiment provides a method for preparing amino-modified recycled fibers for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0090] Step I: Preparation of recycled polyester fibers

[0091] Waste polyester bottle flakes are crushed and fed into a twin-screw melt extruder for melt extrusion, stretching, and cutting to obtain recycled polyester fibers with a length of 4 mm.

[0092] The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 270℃, 270℃, 275℃, 275℃, 285℃, 285℃, 295℃, and 295℃ respectively. The main motor speed of the twin-screw extruder is 80 rpm, the pressure is 100 bar, and the draw ratio is 4.

[0093] Step II: Preparation of pretreated regenerated fibers

[0094] The recycled polyester fiber was placed in a plasma chamber, evacuated to a vacuum state, oxygen was introduced, the discharge power was set to 50W, and the treatment lasted for 1 minute to obtain pretreated recycled fiber.

[0095] Step III: Preparation of amino-modified regenerated fibers

[0096] Weigh out 40g of pretreated regenerated fiber, 50mL of deionized water, 500mL of ethanol and 5g of KH-550 and place them in a reaction vessel. Heat the mixture to 30℃ and keep it at that temperature for 2 hours. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake once with deionized water and ethanol, transfer it to an oven at 50℃ and dry it to constant weight to obtain amino-modified regenerated fiber.

[0097] Example 5

[0098] This embodiment provides a method for preparing amino-modified recycled fibers for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0099] Step I: Preparation of recycled polyester fibers

[0100] Waste polyester bottle flakes are crushed and fed into a twin-screw melt extruder for melt extrusion, stretching, and cutting to obtain recycled polyester fibers with a length of 5mm.

[0101] The twin-screw extruder has eight temperature zones from the feed inlet to the discharge outlet, with temperatures of 270℃, 270℃, 275℃, 275℃, 285℃, 285℃, 295℃, and 295℃ respectively. The twin-screw extruder has a main engine speed of 100 rpm, a pressure of 120 bar, and a draw ratio of 4.5.

[0102] Step II: Preparation of pretreated regenerated fibers

[0103] The recycled polyester fiber was placed in a plasma chamber, evacuated to a vacuum state, oxygen was introduced, the discharge power was set to 100W, and the treatment lasted for 3 minutes to obtain pretreated recycled fiber.

[0104] Step III: Preparation of amino-modified regenerated fibers

[0105] Weigh out 50g of pretreated regenerated fiber, 60mL of deionized water, 700mL of ethanol and 7g of KH-550 and place them in a reaction vessel. Heat the mixture to 40℃ and keep it at that temperature for 3 hours. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 55℃ and dry it to constant weight to obtain amino-modified regenerated fiber.

[0106] Example 6

[0107] This embodiment provides a method for preparing amino-modified recycled fibers for rutting-resistant low-carbon asphalt mixtures, comprising the following steps:

[0108] Step I: Preparation of recycled polyester fibers

[0109] Waste polyester bottle flakes are crushed and fed into a twin-screw melt extruder for melt extrusion, stretching, and cutting to obtain recycled polyester fibers with a length of 6mm.

[0110] The twin-screw extruder has eight temperature zones from the feed inlet to the discharge outlet, with temperatures of 270℃, 270℃, 275℃, 275℃, 285℃, 285℃, 295℃, and 295℃ respectively. The main motor speed of the twin-screw extruder is 120 rpm, the pressure is 150 bar, and the draw ratio is 5.

[0111] Step II: Preparation of pretreated regenerated fibers

[0112] The recycled polyester fiber was placed in a plasma chamber, evacuated to a vacuum state, oxygen was introduced, the discharge power was set to 150W, and the treatment lasted for 5 minutes to obtain pretreated recycled fiber.

[0113] Step III: Preparation of amino-modified regenerated fibers

[0114] Weigh out 60g of pretreated regenerated fiber, 80mL of deionized water, 1000mL of ethanol and 10g of KH-550 and place them in a reaction vessel. Heat the mixture to 50℃ and keep it at that temperature for 4 hours. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 50℃ and dry it to constant weight to obtain amino-modified regenerated fiber.

[0115] Example 7

[0116] This embodiment provides a method for preparing modified rubber powder for rutting-resistant low-carbon asphalt mixtures, including the following steps:

[0117] Weigh out 40g of waste rubber powder, 1g of 2,2'-dibenzoylaminodiphenyl disulfide, 1.5g of zinc oxide, and 60g of naphthenic oil and place them in a reaction vessel. Heat the vessel to 155℃ and stir at 450rpm for 1.5h. After the reaction is complete, allow the reaction system to cool to room temperature, filter, wash the filter cake once with deionized water, transfer it to an oven at 50℃, and dry it to constant weight to obtain modified rubber powder.

[0118] Example 8

[0119] This embodiment provides a method for preparing modified rubber powder for rutting-resistant low-carbon asphalt mixtures, including the following steps:

[0120] Weigh out 60g of waste rubber powder, 1.5g of 2,2'-dibenzoylaminodiphenyl disulfide, 2g of zinc oxide and 80g of naphthenic oil and place them in a reaction vessel. Heat the vessel to 160℃ and stir at 450rpm for 2 hours. After the reaction is complete, wait for the reaction system to cool to room temperature, filter the mixture, wash the filter cake twice with deionized water, transfer it to an oven at 55℃ and dry it to constant weight to obtain modified rubber powder.

[0121] Example 9

[0122] This embodiment provides a method for preparing modified rubber powder for rutting-resistant low-carbon asphalt mixtures, including the following steps:

[0123] Weigh out 80g of waste rubber powder, 2g of 2,2'-dibenzoylaminodiphenyl disulfide, 3g of zinc oxide and 120g of naphthenic oil and place them in a reaction vessel. Heat the vessel to 165℃ and stir at 450rpm for 2.5h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter the mixture, wash the filter cake twice with deionized water, transfer it to an oven at 60℃ and dry it to constant weight to obtain modified rubber powder.

[0124] Example 10

[0125] This embodiment provides a method for preparing a rutting-resistant low-carbon asphalt mixture, including the following steps:

[0126] Step 1: Preparation of activated asphalt

[0127] Weigh 150g of base asphalt and place it in a mixer. Heat the mixture to 150℃ and stir for 5 minutes. Add 5g of dicumyl peroxide and 20g of maleic anhydride. Keep the mixture warm for 1 hour. After the reaction is complete, add 50mL of deionized water to the reaction solution and stir for 1 minute. Then, transfer the solution to an oven at 90℃ and dry for 20 minutes to obtain activated asphalt.

[0128] Step 2: Preparation of mixed slurry

[0129] Weigh out 500g of activated asphalt, 10g of amino-modified regenerated fiber from Example 4, 10g of 4,4'-diaminodiphenylmethane, 5000g of recycled stone, 4000g of steel slag powder, and 20g of modified rubber powder prepared in Example 7. Add these to a mixer, heat to 150°C, and stir for 5 minutes to obtain a mixed slurry.

[0130] Step 3: Preparation of low-carbon asphalt mixture

[0131] Weigh out 50g of the modified epoxy resin prepared in Example 1 and add it to a mixer. Stir for 1 minute, then add 650g of the mixed slurry and stir for 15 minutes to obtain a low-carbon asphalt mixture.

[0132] Example 11

[0133] This embodiment provides a method for preparing a rutting-resistant low-carbon asphalt mixture, including the following steps:

[0134] Step 1: Preparation of activated asphalt

[0135] Weigh 170g of base asphalt and place it in a mixer. Heat the mixture to 155℃ and stir for 7 minutes. Add 7g of dicumyl peroxide and 210g of maleic anhydride. Keep the mixture warm for 1.5 hours. After the reaction is complete, add 70mL of deionized water to the reaction solution and stir for 3 minutes. Then transfer the mixture to an oven at 95℃ and dry for 25 minutes to obtain activated asphalt.

[0136] Step 2: Preparation of mixed slurry

[0137] Weigh out 600g of activated asphalt, 15g of amino-modified regenerated fiber prepared in Example 5, 15g of 4,4'-diaminodiphenylmethane, 6000g of recycled stone, 5000g of steel slag powder, and 30g of modified rubber powder prepared in Example 8, add them to a mixer, heat to 155℃, and stir for 7 minutes to obtain a mixed slurry.

[0138] Step 3: Preparation of low-carbon asphalt mixture

[0139] Weigh out 55g of the modified epoxy resin prepared in Example 2 and add it to the mixer. Stir for 2 minutes, then add 700g of the mixed slurry and stir for 20 minutes to obtain the low-carbon asphalt mixture.

[0140] Example 12

[0141] This embodiment provides a method for preparing a rutting-resistant low-carbon asphalt mixture, including the following steps:

[0142] Step 1: Preparation of activated asphalt

[0143] Weigh 200g of base asphalt and place it in a mixer. Heat the mixture to 160℃ and stir for 10 minutes. Add 10g of dicumyl peroxide and 220g of maleic anhydride. Keep the mixture warm for 2 hours. After the reaction is complete, add 100mL of deionized water to the reaction solution and stir for 5 minutes. Then transfer the solution to an oven at 100℃ and dry for 30 minutes to obtain activated asphalt.

[0144] Step 2: Preparation of mixed slurry

[0145] Weigh out 700g of activated asphalt, 20g of amino-modified regenerated fiber prepared in Example 6, 20g of 4,4'-diaminodiphenylmethane, 7000g of recycled stone, 6000g of steel slag powder, and 40g of modified rubber powder prepared in Example 9, add them to a mixer, heat to 160℃, and stir for 10 minutes to obtain a mixed slurry.

[0146] Step 3: Preparation of low-carbon asphalt mixture

[0147] Weigh out 60g of the modified epoxy resin prepared in Example 3 and add it to the mixer. Stir for 2 minutes, then add 750g of the mixed slurry and stir for 30 minutes to obtain a low-carbon asphalt mixture.

[0148] Comparative Example 1

[0149] The difference between this comparative example and Example 2 is that, in step (2) when preparing the mixed slurry, the pretreated regenerated fiber from step II is used as an equal substitute.

[0150] Comparative Example 2

[0151] The difference between this comparative example and Example 2 is that the addition of modified rubber powder is omitted in step (2) when preparing the mixed slurry.

[0152] Comparative Example 3

[0153] The difference between this comparative example and Example 2 is that, in step (2) when preparing the mixed slurry, the base asphalt is used to replace the activated asphalt in an equal amount.

[0154] Comparative Example 4

[0155] The difference between this comparative example and Example 2 is that, in step (3) when preparing the low-carbon asphalt mixture, an equal amount of bisphenol A type epoxy resin is used to modify the epoxy resin.

[0156] Performance testing:

[0157] Marshall specimens were prepared from asphalt mixtures prepared in Examples 10-12 and Comparative Examples 1-4 in accordance with the standard JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The preparation method was the compaction method. The shear strength, fracture strength, dynamic stability and average linear shrinkage coefficient of the specimens were measured. The specific data are shown in Table 1.

[0158] Table 1 - Performance Test Data for Each Sample

[0159] Project Group Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Shear strength / MPa 3.14 3.22 3.16 2.32 2.15 2.12 2.09 Fracture strength / MPa 2.48 2.56 2.44 1.87 1.77 1.75 1.65 <![CDATA[Dynamic stability / times·mm -1 > 3625 3659 3620 3215 3211 3255 3129 <![CDATA[Coefficient of linear shrinkage / 1·°C -1 ×10 -5 > 0.72 0.68 0.74 0.82 0.81 0.89 0.94

[0160] Data Analysis:

[0161] A comparative analysis of the data in Table 1 reveals that the low-carbon asphalt mixture prepared in this invention has a shear strength of 3.22 MPa, a fracture strength of 2.56 MPa, and a dynamic stability of 3659 cycles / mm. -1 The average linear contraction coefficient is 0.68 1·℃. -1 ×10 -5 ;

[0162] By comparing the table data of Example 12 and Comparative Example 1, it was found that the shear strength, breaking strength and dynamic stability of Comparative Example 1 decreased significantly. This indicates that the present invention obtains recycled polyester fiber by melt spinning waste polyester bottle flakes, and further obtains amino-modified recycled fiber by plasma treatment and silane coupling agent modification of the recycled polyester fiber. The plasma treatment introduces oxygen-containing functional groups such as carboxyl, hydroxyl and epoxy groups on the surface of the recycled polyester fiber, which improves the reactivity of the recycled polyester fiber. The amino functional layer after silane coupling agent modification significantly enhances the interfacial adhesion and interfacial stability between the fiber and the asphalt mixture, significantly improves the shear resistance and crack resistance of the asphalt mixture, and the chopped polyester fiber is distributed in the mixture in a multi-directional network structure, which restricts the micro-deformation of the asphalt mixture and improves its rutting resistance.

[0163] By comparing the tabular data of Example 12 and Comparative Example 2, it was found that the shear strength, fracture strength, and dynamic stability of Comparative Example 2 decreased significantly. This indicates that the present invention, through catalytic depolymerization of waste rubber powder, breaks the disulfide bonds in the waste rubber powder and introduces oxygen-containing functional groups to obtain modified rubber powder. After catalytic depolymerization and breaking of disulfide bonds, the molecular weight of the waste rubber powder decreases and its fluidity increases. At the same time, the introduced oxygen-containing functional groups can chemically bond with the modified epoxy resin in asphalt to form a three-dimensional elastic cross-linked network, significantly improving the compatibility of the matrix in the asphalt mixture and avoiding phase separation problems. Under high temperature conditions, it can effectively inhibit the flow and plastic deformation of asphalt, thereby improving rutting resistance. Furthermore, under repeated cyclic loading, road materials are prone to microcracks that gradually propagate and lead to fatigue failure. Due to its good elasticity and flexibility, the rubber powder plays a stress buffering and energy absorption role in the composite system, which can alleviate stress concentration at the microcrack tip and thus delay the crack propagation rate. This elastic regulation effect significantly improves the mechanical properties of asphalt mixtures.

[0164] By comparing the table data of Example 12 and Comparative Example 3, it was found that the shear strength, fracture strength and dynamic stability of Comparative Example 3 decreased significantly, while the average linear shrinkage coefficient increased. This indicates that grafting maleic anhydride into the base asphalt gives the base asphalt surface more reaction sites, enhances the interfacial adhesion between the base asphalt and modified rubber powder, amino-modified regenerated fiber and modified epoxy resin, and further improves the mechanical properties and high temperature resistance of the asphalt mixture.

[0165] By comparing the tabular data of Example 12 and Comparative Example 4, it was found that the shear strength, fracture strength, and dynamic stability of Comparative Example 4 decreased significantly, while the average linear shrinkage coefficient increased significantly. This indicates that the present invention, by preparing intermediate I containing borate ester groups, and further preparing intermediate II containing borate esters using isophorone diisocyanate as the hard segment and polytetrahydrofuran as the soft segment, and then combining intermediate II with bisphenol A... Modified epoxy resins, through chemical bonding, are obtained with self-healing properties. When microcracks appear on the asphalt surface, the modified epoxy resin can automatically repair the cracks through a self-healing mechanism, preventing crack propagation and thus extending the service life of the pavement. Epoxy resins have strong chemical stability and, through interaction with activated asphalt, amino-modified regenerated fibers, curing agents, and modified rubber powder, form a more stable, robust, and elastic material network structure. This effectively improves the mechanical properties of asphalt, mitigates thermal cracking and thermal expansion in high-temperature environments, and further enhances the rutting resistance and high-temperature resistance of asphalt mixtures. Furthermore, during the preparation of asphalt mixtures, in addition to the curing agent 4,4'-diaminodiphenylmethane, activated asphalt, amino-modified regenerated fibers, curing agents, and modified rubber powder can all participate in promoting the curing process of the modified epoxy resin, reducing the curing time and temperature required for curing, and improving the mechanical properties of the cured asphalt mixture.

[0166] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for producing a low-carbon anti-rut asphalt mixture, characterized by, It comprises the following steps: S1, the matrix asphalt is placed in a blender, heated to 150-160℃, stirred for 5-10min, add dicumyl peroxide and maleic anhydride, heat reaction 1-2h, post-processing to obtain activated asphalt; S2, the activated asphalt, amino modified regenerated fiber, curing agent, recycled stone, steel slag powder and modified rubber powder are added into the blender, heated to 150-160℃, stirred for 5-10min, to obtain mixed slurry; S3, the modified epoxy resin is added into the blender, stirred for 1-2min, add mixed slurry, stirred for 15-30min, to obtain low carbon asphalt mixture; In step S1, the amino modified regenerated fiber is prepared by the following steps: A1, the waste polyester bottle pieces are crushed and added into a twin-screw melt extruder, melt extruded, drawn, and cut short to obtain regenerated polyester fiber; A2, the regenerated polyester fiber is treated by plasma to obtain pretreated regenerated fiber; A3, the pretreated regenerated fiber, deionized water, ethanol and KH-550 are placed in a reaction kettle, heated to 30-50℃, heat reaction 2-4h, post-processing to obtain amino modified regenerated fiber; In step S1, the preparation method of the modified rubber powder is as follows: the waste rubber powder, 2,2'-dibenzoylaminodiphenyl disulfide, zinc oxide and naphthenic oil are placed in a reaction kettle, heated to 155-165℃, heat stirring for 1.5-2.5h, post-processing to obtain modified rubber powder; In step S3, the modified epoxy resin is prepared by the following steps: B1, 1,4-phenyl boric acid, 1,2,5-pentanetriol and tetrahydrofuran are placed in a reaction kettle, anhydrous magnesium sulfate is added, and reaction is carried out at room temperature for 20-24h, post-processing to obtain intermediate I; B2, intermediate I, polytetrahydrofuran and N,N-dimethylformamide are placed in a reaction kettle protected by nitrogen atmosphere, stirred for 1-5min, add dibutyltin dilaurate and calculated amount of isophorone diisocyanate, heated to 95-105℃, heat reaction 1-2h, to obtain intermediate II; B3, intermediate II and bisphenol A type epoxy resin are placed in a reaction kettle protected by nitrogen atmosphere, add dibutyltin dilaurate, heated to 80-90℃, heat reaction 2-4h, post-processing to obtain modified epoxy resin.

2. A process for the preparation of a low carbon, skid resistant asphalt mix as claimed in claim 1, wherein, In step S1, the amount ratio of the matrix asphalt, dicumyl peroxide and maleic anhydride is 15-20g:0.5-1g:20-22g; In step S2, the amount ratio of the activated asphalt, amino modified regenerated fiber, curing agent, recycled stone, steel slag powder and modified rubber powder is 50-70g:1-2g:1-2g:500-700g:400-600g:2-4g, the curing agent is 4,4'-diaminodiphenyl methane; in step S3, the amount ratio of the modified epoxy resin and mixed slurry is 5-6g:65-75g.

3. The method of claim 1, wherein the low carbon asphalt mixture is prepared by mixing the low carbon asphalt binder with the aggregate at a temperature of 140 to 160°C. The length of the regenerated polyester fiber in step A1 is 4-6 mm; the amount ratio of the pretreated regenerated fiber, deionized water, ethanol and KH-550 in step A3 is 4-6 g:5-8 mL:50-100 mL:0.5-1 g.

4. The method of claim 1, wherein the low carbon asphalt mixture is prepared by mixing the low carbon asphalt binder and the aggregate at a temperature of 140 to 160°C. The amount ratio of the waste and old rubber powder, 2,2'-diphenylcarbonylaminodiphenyl disulfide, zinc oxide and naphthenic oil is 4-8 g:0.1-0.2 g:0.15-0.3 g:6-12 g, and the stirring rate of the modified rubber powder is 450 rpm.

5. The method of claim 1, wherein the low carbon asphalt mixture is prepared by mixing the low carbon asphalt binder with the aggregate at a temperature of 140- 160°C. In step B1, the amount ratio of 1,4-phenyl boric acid, 1,2,5-pentanetriol, tetrahydrofuran and anhydrous magnesium sulfate is 2-4 g:6-8 g:100-120 mL:10-12 g; in step B2, the amount ratio of the intermediate I, polytetrahydrofuran, N,N-dimethylformamide and dibutyltin dilaurate is 1-2 g:7-10 g:120-150 mL:0.2-0.5 g, and in the reaction, the isophorone diisocyanate is 0.55 times of the molar amount of hydroxyl in the reaction system, and the weight ratio of the intermediate I and polytetrahydrofuran is 1-2:7-10; in step B3, the amount ratio of the intermediate II, bisphenol A type epoxy resin and dibutyltin dilaurate is 5-7 g:6-10 g:0.5-1 g.

6. A low carbon, rut resistant asphalt mixture characterized by, The anti-rutting low-carbon asphalt mixture is prepared by the method according to any one of claims 1-5.

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