Warm-mixing large-proportion recycled asphalt mixture

Abstract

The invention relates to the technical field of recycled asphalt, and relates to a warm-mixing large-proportion recycled asphalt mixture, which is prepared from the following ingredients in parts by weight: 4 to 6 parts of modified asphalt, 60 to 80 parts of waste asphalt, 10 to 20 parts of regenerant, 1 to 5 parts of Evotherm warm-mixing agent, 20 to 30 parts of coarse aggregate, 5 to 10 parts of fine aggregate and 2 to 3 parts of mineral powder, the modified asphalt is prepared by modifying alumina fiber asphalt with a phosphate coupling agent, the regenerant is prepared by mixing aromatic hydrocarbon oil and tung oil according to the mass ratio of 7: (1-2), the modified asphalt is prepared from the modified fibers and then mixed with the waste asphalt, so that the overall structural stability of the mixture is enhanced, and the crack resistance and durability of the mixture are improved; meanwhile, the alumina fiber has excellent thermal stability, so that the thermal stability of the asphalt mixture is improved, and the service life of the asphalt pavement is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of recycled asphalt, in particular to a warm-mix large-proportion recycled asphalt mixture. Background Art

[0002] Asphalt is a dark brown complex mixture composed of hydrocarbons of different molecular weights and their non-metallic derivatives. It is a kind of high-viscosity organic liquid. It is in liquid state with a black surface and is soluble in carbon disulfide. Asphalt can be divided into coal tar asphalt, petroleum asphalt and natural asphalt. Among them, coal tar asphalt is a by-product of coking, petroleum asphalt is the residue after crude oil distillation, and natural asphalt is stored underground. Some form mineral layers or accumulate on the surface of the earth's crust. Asphalt is mainly used in industries such as coatings, plastics, rubber, and pavement. With the passing of the peak period of highway construction in my country, road maintenance has become normal. Asphalt pavement is the main form of highway pavement. Due to the particularity of my country's traffic load, the service life of high-grade highways is generally 6 to 10 years, and other roads are generally 5 to 8 years. In the meantime or later, they will enter major and medium repairs, and the milled materials were initially discarded as garbage.

[0003] At present, the most common practice is to mix aged asphalt and new asphalt to make a recycled asphalt mixture, so as to achieve the effect of recycling. However, the conventional recycled asphalt mixture has a poor effect after paving. Most of the aged asphalt properties are not activated, which makes the asphalt pavement easy to crack and has major defects. In view of this, a warm-mix large-proportion recycled asphalt mixture is provided. Summary of the invention

[0004] The purpose of the present invention is to provide a warm-mix large-proportion recycled asphalt mixture to solve the problem of poor stability and durability of traditional recycled asphalt mixtures mentioned in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention aims to provide a warm-mix large-proportion recycled asphalt mixture, comprising the following components in parts by weight: 5-10 parts by weight of modified asphalt, 100-150 parts by weight of waste asphalt, 10-15 parts by weight of regeneration agent, 10-15 parts by weight of Evotherm warm-mix agent, 10-15 parts by weight of coarse aggregate, 10-15 parts by weight of fine aggregate, and 10-15 parts by weight of mineral powder, wherein the modified asphalt is prepared by modifying alumina fiber asphalt with a phosphate coupling agent, and the regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1 to 2.

[0006] As a further improvement of the technical solution, the preparation method of the modified asphalt is as follows:

[0007] A phosphate coupling agent solution is diluted with butanol to a certain concentration, and alumina fibers are added to the solution to be infiltrated to obtain modified fibers. The modified fibers are then added to asphalt and stirred evenly with a stirrer to obtain modified asphalt.

[0008] Phosphate coupling agents are a special class of chemicals that are mainly used to improve the interfacial adhesion between inorganic fillers or reinforcing materials and organic polymer matrices. They generally contain two functional areas: one that can react with hydroxyl groups on the surface of inorganic materials (such as silica, glass, metal oxides, etc.), and the other that can react chemically with organic polymers or enhance compatibility through physical action. They are like "molecular bridges" that enhance the bonding between two different materials, thereby improving the overall performance of the composite material. The structure of phosphate coupling agents usually contains a phosphate group, which can form phosphate bonds through hydration with the surface of inorganic materials, thereby firmly attaching to inorganic fillers. At the same time, they also have functional groups that interact with organic polymers, such as amine groups, epoxy groups, thiol groups or carbon chains, which help to disperse and stabilize inorganic fillers in organic matrices.

[0009] Alumina fiber is an advanced inorganic non-metallic material, mainly composed of aluminum oxide (Al2O3), usually containing about 5% silicon dioxide (SiO2) as a flux to stabilize the crystal phase and inhibit grain growth at high temperatures. The diameter of alumina fiber is generally 3-7 microns, and the length of a single fiber is between 10-150 mm. It is white, soft and elastic, similar to cotton wool. Its operating temperature can reach 1450℃ to 1600℃, and its melting point is as high as 1840℃. Therefore, it has good thermal stability, high temperature tolerance, chemical stability and low thermal conductivity.

[0010] Since alumina fibers easily absorb moisture in the air to form hydroxyl groups, this provides a reaction site for the coupling agent. When the phosphate coupling agent contacts the surface of the alumina fiber, the phosphorus atom in its phosphate group can form a phosphate bond (PO-Al) with the hydroxyl groups on the fiber surface. This is a covalent bond, thereby fixing the coupling agent molecules on the fiber surface. In this way, the phosphate coupling agent forms a coupling protective film on the fiber surface by surface grafting, which protects the fiber and enhances the mechanical properties of the fiber. When the concentration of the coupling agent is too high, it will slightly corrode the fiber structure and the fiber surface will over-react, resulting in certain damage to the fiber molecular structure, thereby deteriorating the mechanical properties of the fiber.

[0011] Alumina fibers modified with phosphate coupling agents are combined with asphalt. On the one hand, since the modified fibers exist in the modified asphalt system in a staggered manner, the asphalt attached to the fiber surface forms a good wetting interface with the surrounding asphalt, effectively reducing the generation of fracture surfaces. In addition, this staggered structure allows the fibers to connect with each other to form a skeleton structure, which enhances the overall structural stability, reduces the relative slip between aggregates, effectively transmits and dissipates stress, thereby reducing stress concentration and preventing the development of cracks. At the same time, the addition of modified asphalt can effectively connect various parts in the asphalt mixture system. , resisting the softening and deformation caused by high temperature, and improving the durability of the road surface; on the other hand, due to the rough concave-convex structure on the surface of the modified fiber, the specific surface area of ​​the fiber is increased, which plays a role of "mechanical anchoring", so that the fiber and asphalt are tightly integrated into a whole, and the bonding performance of the fiber and asphalt is enhanced, thereby enhancing the shear deformation resistance of the mixture. In addition, the increase in specific surface area can also absorb more asphaltene and light components, improve the viscosity of aged asphalt, reduce the volatilization of light components, effectively improve the anti-aging performance and stability of the asphalt mixture, and improve the durability of the road surface.

[0012] Since the surface of alumina fiber has a certain degree of hydrophilicity, the hydrophilicity of the modified alumina fiber is greatly reduced due to the reaction of a part of the hydroxyl groups with the coupling agent. This means that the interfacial bonding force between the modified fiber and asphalt is enhanced, the bonding strength between the fiber and asphalt is increased, and more asphalt is coated on the fiber surface, which reduces the relative slip between the fiber and asphalt and improves the stability of the bonding area structure, thereby avoiding the occurrence of bonding failure. It helps to improve the road surface's resistance to cracking. Improve the asphalt pavement in low temperature environments, thereby improving the durability of the road surface, reducing cracks and damage, and extending the service life of the asphalt pavement. Since alumina fiber also has excellent thermal stability, the modified asphalt is not easy to soften or flow in high temperature environments, maintaining the shape and strength of the road surface and extending the service life of the road.

[0013] As a further improvement of the technical solution, the mass fraction of the phosphate coupling agent solution is 6-12%.

[0014] As a further improvement of the technical solution, the infiltration time is 50-100 minutes.

[0015] As a further improvement of the technical solution, the alumina fiber accounts for 0.1-0.3% of the mass of the asphalt.

[0016] As a further improvement of the technical solution, the rotation speed of the agitator is 1000-1200 rpm / min.

[0017] As a further improvement of the technical solution, the specific preparation method of the warm mix large proportion recycled asphalt mixture is as follows:

[0018] Preheat the waste asphalt in an oven, then add the regeneration agent, stir with a stirrer for 3-5 minutes, add coarse aggregate and fine aggregate, continue stirring for 3-5 minutes, add the preheated modified asphalt and warm mix agent to the mixture, stir for 10-15 minutes, and finally add the mineral powder and stir for 15-30 minutes to obtain a warm mix large-proportion recycled asphalt mixture.

[0019] Due to the obvious honeycomb structure in aged asphalt, the surface roughness of the asphalt increases. The increase in surface roughness indicates that the unevenness of the asphalt increases. Material unevenness easily leads to stress concentration, which is also the reason why asphalt is prone to cracking after aging. At the same time, due to the volatilization of oil, the increase of asphaltene and colloid, the viscosity of asphalt increases, making the aging phenomenon more and more obvious. The addition of regeneration agent fills the molecular gaps of asphalt, restores the uniformity of asphalt, reduces the viscosity of asphalt, and thus restores the performance of aged asphalt.

[0020] Since recycled waste asphalt contains many micropores and damages, mineral powder is added to fill the tiny gaps in the mixture, reducing the void ratio, helping to form a denser structure and increasing the contact area between asphalt and aggregate, thereby improving the bonding force and overall stability, compensating for the weakened adhesion between asphalt and aggregate due to aging, and at the same time dispersing stress when subjected to traffic loads and environmental stresses, thereby improving the strength and stability of the recycled asphalt mixture. Since mineral powder is cheap, it can also reduce the demand for new aggregates and reduce the overall cost of raw materials.

[0021] As a further improvement of the technical solution, the preheating temperature of the waste asphalt is 130-150°C, and the preheating time is 1.5-2h.

[0022] As a further improvement of the technical solution, the rotation speed of the agitator is 1500-2000 rpm / min.

[0023] As a further improvement of the technical solution, the preheating temperature of the modified asphalt and the warm mix agent is 100-130°C, and the preheating time is 30-50 minutes.

[0024] Warm mix regeneration agent refers to a type of additive that can enable asphalt mixture to achieve good construction performance at lower temperatures. Its main mechanism of action is to reduce the viscosity of the mixture, allowing it to be easily mixed and compacted at lower temperatures, thereby reducing energy consumption and harmful emissions. It can also improve construction conditions and extend the construction season.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the warm mix large proportion recycled asphalt mixture, modified asphalt is prepared with modified fibers. Since the modified fibers exist in the modified asphalt system in a staggered manner, the fibers and asphalt are interconnected to form a skeleton structure, which enhances the overall structural stability, reduces the relative slip between aggregates, and effectively transmits and dissipates stress, thereby reducing stress concentration and preventing the development of cracks. At the same time, the surface of the modified fiber is a rough concave-convex structure, which increases the specific surface area of ​​the fiber, and the bonding performance between the fiber and asphalt is enhanced, thereby enhancing the stability of the mixture. In addition, the alumina fiber itself has excellent thermal stability, which makes the modified asphalt not easy to soften or flow in a high temperature environment, thereby maintaining the shape and strength of the road surface and extending the service life of the asphalt road surface. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] The warm-mix large-proportion recycled asphalt mixture includes the following components in parts by weight: 4-6 parts by weight of modified asphalt, 60-80 parts by weight of waste asphalt, 10-20 parts by weight of regeneration agent, 1-5 parts by weight of Evotherm warm-mix agent, 20-30 parts by weight of coarse aggregate, 5-10 parts by weight of fine aggregate, and 2-3 parts by weight of mineral powder, wherein the modified asphalt is prepared from alumina fiber asphalt modified by a phosphate coupling agent, and the regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1 to 2.

[0029] Example 1

[0030] In this embodiment, the specific preparation method of the warm mix large proportion recycled asphalt mixture is as follows:

[0031] S3.1. Prepare the components: 4 parts by weight of modified asphalt, 70 parts by weight of waste asphalt, 15 parts by weight of regeneration agent, 3 parts by weight of Evotherm warm mix agent, 25 parts by weight of coarse aggregate, 8 parts by weight of fine aggregate, and 2 parts by weight of mineral powder. The regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1.

[0032] S3.2. Preparation of modified asphalt: dilute with butanol to a 9% by mass phosphate coupling agent solution, add alumina fiber to the solution and soak for 60 minutes to obtain modified fiber, then add the modified fiber to the asphalt, wherein the alumina fiber accounts for 0.1% of the asphalt mass, set the agitator speed to 1000 rpm / min to stir the mixture evenly to obtain modified asphalt.

[0033] S3.3. Preparation of warm-mix large-proportion recycled asphalt mixture: preheat the waste asphalt in an oven at 130°C for 1.5 hours, then add the regeneration agent, set the agitator speed to 1500rpm / min and stir for 5 minutes, add coarse aggregate and fine aggregate, continue stirring for 5 minutes, preheat the modified asphalt and warm-mix agent at 100°C for 30 minutes, then add them to the mixture, stir for 10 minutes, and finally add the mineral powder and stir for 15 minutes to obtain a warm-mix large-proportion recycled asphalt mixture.

[0034] Example 2

[0035] In this embodiment, the specific preparation method of the warm mix large proportion recycled asphalt mixture is as follows:

[0036] S3.1. Prepare components: 5 parts by weight of modified asphalt, 70 parts by weight of waste asphalt, 15 parts by weight of regeneration agent, 3 parts by weight of Evotherm warm mix agent, 25 parts by weight of coarse aggregate, 8 parts by weight of fine aggregate, and 2 parts by weight of mineral powder. The regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1.

[0037] S3.2. Preparation of modified asphalt: dilute with butanol to a 9% by mass phosphate coupling agent solution, add alumina fiber to the solution and soak for 60 minutes to obtain modified fiber, then add the modified fiber to the asphalt, wherein the alumina fiber accounts for 0.1% of the asphalt mass, set the agitator speed to 1000 rpm / min to stir the mixture evenly to obtain modified asphalt.

[0038] S3.3. Preparation of warm-mix large-proportion recycled asphalt mixture: preheat the waste asphalt in an oven at 130°C for 1.5 hours, then add the regeneration agent, set the agitator speed to 1500rpm / min and stir for 5 minutes, add coarse aggregate and fine aggregate, continue stirring for 5 minutes, preheat the modified asphalt and warm-mix agent at 100°C for 30 minutes, then add them to the mixture, stir for 10 minutes, and finally add the mineral powder and stir for 15 minutes to obtain a warm-mix large-proportion recycled asphalt mixture.

[0039] Example 3

[0040] In this embodiment, the specific preparation method of the warm mix large proportion recycled asphalt mixture is as follows:

[0041] S3.1. Prepare the components: 6 parts by weight of modified asphalt, 70 parts by weight of waste asphalt, 15 parts by weight of regeneration agent, 3 parts by weight of Evotherm warm mix agent, 25 parts by weight of coarse aggregate, 8 parts by weight of fine aggregate, and 2 parts by weight of mineral powder. The regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1.

[0042] S3.2. Preparation of modified asphalt: dilute with butanol to a 9% by mass phosphate coupling agent solution, add alumina fiber to the solution and soak for 60 minutes to obtain modified fiber, then add the modified fiber to the asphalt, wherein the alumina fiber accounts for 0.1% of the asphalt mass, set the agitator speed to 1000 rpm / min to stir the mixture evenly to obtain modified asphalt.

[0043] S3.3. Preparation of warm-mix large-proportion recycled asphalt mixture: preheat the waste asphalt in an oven at 130°C for 1.5 hours, then add the regeneration agent, set the agitator speed to 1500rpm / min and stir for 5 minutes, add coarse aggregate and fine aggregate, continue stirring for 5 minutes, preheat the modified asphalt and warm-mix agent at 100°C for 30 minutes, then add them to the mixture, stir for 10 minutes, and finally add the mineral powder and stir for 15 minutes to obtain a warm-mix large-proportion recycled asphalt mixture.

[0044] Comparative Example 1

[0045] The method of Example 2 was adopted without adding modified asphalt.

[0046] Comparative Example 2

[0047] The method of Example 2 was adopted to increase the fiber content so that the alumina fiber accounted for 0.3% of the asphalt mass.

[0048] The present invention prepares a warm-mix large-proportion recycled asphalt mixture, which has good stability and durability in the application of the recycled asphalt technology field, and prolongs the service life of the road. Specific tests are shown in the following table;

[0049] Dynamic stability is an evaluation index of asphalt mixture in rutting test, which describes the ability of mixture to resist rutting deformation, that is, dynamic stability is the number of times wheel load acts when the mixture specimen produces 1mm deformation under given temperature and constant load conditions; the specific steps of stability test are as follows: first, prepare the specimen according to the prescribed standard, the specimen length is 300mm, the width is 300mm, and the thickness is 50mm. Place the prepared specimen in a constant temperature chamber at 60℃ and keep it for a certain time to ensure that the temperature of the specimen is uniform during the test. Install the specimen on the rutting test machine, ensure that the specimen is correctly aligned with the upper and lower pressure heads, and set the test temperature. At 6°C and wheel pressure 0.7MPa, start the testing machine and let the standard wheel roll back and forth on the specimen at a constant speed, such as 42 times / min. Record the deformation of the specimen surface and the number of standard wheel travels until the permanent deformation of the specimen surface reaches a predetermined value of 25mm. Record the total number of standard wheel travels at this time, and calculate the dynamic stability based on the total number of standard wheel travels divided by the permanent deformation of the specimen surface. Higher dynamic stability means that the mixture has stronger anti-rutting ability and can better resist permanent deformation caused by repeated vehicle loads. A mixture with high dynamic stability can reduce the formation of rutting and improve driving safety and comfort.

[0050] The splitting tensile strength is measured by a splitting test, which indicates the ability of the mixture to resist tensile failure caused by vertical load. First, prepare asphalt mixture specimens according to the test requirements. Usually, the specimens are cylinders with a diameter of 101.6 mm (± 0.25 mm) and a height of 63.5 mm (± 1.3 mm). The prepared specimens need to be heat-insulated at a specified temperature (such as 15°C ± 0.5°C) to simulate the environment under actual use conditions. Place the specimen in the clamping device of the splitting test machine to ensure that the specimen is fixed vertically. Apply pre-pressure at both ends to ensure that the specimen does not slide or flip during the test. Turn on the test machine and perform splitting loading on the specimen at a specified loading rate of 50 mm / min. Record the maximum load and corresponding deformation data of the specimen before failure, and calculate the splitting tensile strength based on the test data. A higher splitting tensile strength indicates that the mixture has better low-temperature crack resistance and fatigue resistance. The higher the splitting tensile strength, the less likely the mixture is to crack at low temperatures and is less likely to fatigue failure under repeated loads, thereby improving the durability and reliability of the pavement.

[0051] Failure strain refers to the maximum strain experienced by a material when it is deformed from its initial state to irreversible failure under the action of an external load. The test method for failure strain is as follows: First, prepare a mixture specimen. The shape of the specimen is a cylindrical test piece with a diameter of 100mm and a height of 100mm. Install it on a splitting tester to ensure that the axis of the specimen is consistent with the loading direction. Set the loading rate to 2mm / min and the test temperature to 10℃. Start the test equipment and gradually apply force to the specimen. During the test, record the force and displacement data to draw a force and displacement curve and take the peak strength value. The corresponding strain is the failure strain, which is used to evaluate the toughness and durability of asphalt mixtures. Higher failure strain values ​​usually indicate that the material has better ductility and energy absorption capacity. The larger the failure strain, the higher the toughness of the asphalt mixture, and the better it can adapt to temperature changes and traffic loads, reduce cracking and rutting, and extend the service life of the road. The better the durability and fatigue resistance of the mixture, the smaller the failure strain, which reflects that the mixture is prone to damage when subjected to less stress, and the road will develop cracks, potholes or other forms of damage more quickly, and the adaptability and elasticity of the mixture will be worse.

[0052] The obtained data are shown in Table 1

[0053] Table 1 Road performance data of warm mix large proportion recycled asphalt mixture of Examples 1-3 and Comparative Examples 1-2

[0054]

[0055] By comparing Example 1-3 with Comparative Example 1-2, it can be seen that adding modified asphalt to the warm-mix large-proportion recycled asphalt mixture will have a significant impact on the road performance.

[0056] With the increase of modified asphalt content, the road performance of warm mix large proportion recycled asphalt mixture increases significantly. First, modified asphalt is prepared from modified fiber. Since the modified fiber surface is rough and concave-convex structure, it has a large specific surface area and can form a network structure in asphalt, which is conducive to the close integration of fiber and asphalt into a whole, enhancing the interfacial bonding force between the two and playing the role of "mechanical anchoring". Therefore, after adding modified asphalt to asphalt mixture, the high temperature stability of asphalt mixture is improved, rutting formation is reduced, and the toughness and crack resistance of the mixture are improved. Secondly, the fiber plays the role of skeleton support in asphalt mixture. Since the modified fiber exists in the modified asphalt system in a staggered manner, this staggered The structure enables the fiber to effectively connect various parts of the asphalt mixture system, enhance the overall structural stability, reduce the relative slip between aggregates, effectively transfer and dissipate stress, thereby reducing stress concentration and preventing the development of cracks, and improving the crack resistance and durability of the pavement. At the same time, the addition of fibers can fill the gaps, allowing the asphalt mixture to form a dense structure, thereby increasing the density of the mixture and effectively improving the strength performance of the pavement. Finally, since the modified asphalt is added to the mixture as new asphalt, it can supplement the volatile components in the waste asphalt. Its new bonding medium and lower viscosity improve the mechanical properties of the waste asphalt, significantly improving the road performance of the warm-mixed, large-proportion recycled asphalt mixture.

[0057] Since the cost of fiber is relatively high, the appropriate modified asphalt content should be selected based on the construction cost.

[0058] According to the above test experiments, Example 3 is used as an economical example and compared with Comparative Examples 1-2 respectively.

[0059] By comparing Example 3 and Comparative Example 1, it can be seen that when modified asphalt is not used, the road performance of the warm-mixed large-proportion recycled asphalt mixture is significantly reduced. This is because the modified asphalt prepared by modified fibers has good stability and durability. Due to the rough surface structure of the modified fibers, the interfacial bonding force of asphalt on the fiber surface is enhanced, which reduces the relative slip between the fiber and the asphalt and improves the stability of the bonding area. The larger specific surface area can adsorb asphalt and light components, improve the viscosity of aged asphalt, reduce the volatilization of more light components, effectively improve the anti-aging performance of the asphalt mixture, and improve the durability of the pavement. Therefore, when modified asphalt is not used to prepare the mixture, its road performance is greatly reduced.

[0060] By comparing Example 3 and Comparative Example 2, it can be seen that with the increase of fiber content, the road performance of the warm-mixed large-proportion recycled asphalt mixture is significantly reduced. This is because when the fiber content is too high, the viscosity of the asphalt mixture will increase, making the mixture more viscous and difficult to mix. The fluidity of the mixture will deteriorate, and paving and compaction will become more difficult, which is not conducive to construction. The mixture will also harden at high temperatures due to excessive viscosity, which will reduce the high-temperature rutting resistance. Secondly, the cost of fiber is relatively high, and excessive addition will increase the production cost of the mixture, resulting in a waste of resources. In addition, a high content of fiber will cause the mixture to agglomerate during the mixing process, forming fiber clumps, affecting the uniformity of the mixture, reducing the compaction quality and the flatness of the road surface, and the inability to lay the mixture evenly will increase the porosity of the road surface, thereby reducing the durability and stability of the mixture.

[0061] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Warm mix large proportion recycled asphalt mixture, characterized by: The invention comprises the following components in parts by weight: 4-6 parts by weight of modified asphalt, 60-80 parts by weight of waste asphalt, 10-20 parts by weight of regeneration agent, 1-5 parts by weight of Evotherm warm mix agent, 20-30 parts by weight of coarse aggregate, 5-10 parts by weight of fine aggregate, and 2-3 parts by weight of mineral powder; The modified asphalt is prepared by modifying alumina fiber asphalt with a phosphate coupling agent; the regeneration agent is a mixture of aromatic oil and tung oil in a mass ratio of 7:1 to 2.

2. The warm mix large proportion recycled asphalt mixture according to claim 1, characterized in that: The preparation method of the modified asphalt is as follows: A phosphate coupling agent solution is diluted with butanol to a certain concentration, and alumina fibers are added to the solution to be infiltrated to obtain modified fibers. The modified fibers are then added to asphalt and stirred evenly with a stirrer to obtain modified asphalt.

3. The warm mix large proportion recycled asphalt mixture according to claim 2, characterized in that: The mass fraction of the phosphate coupling agent solution is 6-12%.

4. The warm mix large proportion recycled asphalt mixture according to claim 2, characterized in that: The infiltration time is 50-100 minutes.

5. The warm mix large proportion recycled asphalt mixture according to claim 2, characterized in that: The alumina fibers account for 0.1-0.3% of the mass of the asphalt.

6. The warm mix large proportion recycled asphalt mixture according to claim 7, characterized in that: The rotation speed of the stirrer is 1000-1200 rpm / min.

7. The warm mix large proportion recycled asphalt mixture according to claim 2, characterized in that: The specific preparation method of the warm mix large proportion recycled asphalt mixture is as follows: Preheat the waste asphalt in an oven, then add the regeneration agent, stir with a stirrer for 3-5 minutes, add coarse aggregate and fine aggregate, continue stirring for 3-5 minutes, add the preheated modified asphalt and warm mix agent to the mixture, stir for 10-15 minutes, and finally add mineral powder and stir for 15-30 minutes to obtain a warm mix large-proportion recycled asphalt mixture.

8. The warm mix large proportion recycled asphalt mixture according to claim 7, characterized in that: The waste asphalt preheating temperature is 130-150° C., and the preheating time is 1.5-2 hours.

9. The warm mix large proportion recycled asphalt mixture according to claim 7, characterized in that: The rotation speed of the stirrer is 1500-2000 rpm / min.

10. The warm mix large proportion recycled asphalt mixture according to claim 7, characterized in that: The preheating temperature of the modified asphalt and the warm mix agent is 100-130°C, and the preheating time is 30-50 minutes.

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