Tire multi-element solid waste modified asphalt and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, and discloses tire multi-element solid waste modified asphalt and a preparation method thereof. The tire multi-element solid waste modified asphalt is prepared from the following raw materials in parts by weight: 900 to 1300 parts of asphalt, 80 to 120 parts of waste tire rubber, 20 to 30 parts of modified nano zinc oxide and 60 to 80 parts of modified nano carbon black, 20-60 parts of a resin material; the waste tire rubber material is obtained by mixing waste tire rubber powder and a softening agent according to the weight ratio of (2-3): 1; the waste tire rubber powder is obtained by crushing waste tires, and the particle size of the waste tire rubber powder is 0.45-5.60 mm; the modified nano-zinc oxide is obtained by modifying nano-zinc oxide with palmitic acid and cellulose nanofibers; the modified nano carbon black is obtained by modifying nano carbon black with polypropylene glycol. According to the tire multi-element solid waste modified asphalt and the preparation method thereof, carbon black, resin, zinc oxide, a softening agent and other multi-element solid waste materials recycled in tire production are effectively utilized, and the problem that rubber asphalt prepared from rubber powder prepared from pure waste tires is insufficient in comprehensive performance is solved.

Description

Technical Field

[0001] This application belongs to the technical field of road engineering materials, and in particular relates to a tire multi-element solid waste modified asphalt and its preparation method. Background Technology

[0002] With the rapid development of the automotive and transportation industries, a large number of waste tires have been generated. As solid waste, the open-air dumping of waste tires affects the environment and is known as "black pollution." The accumulation of large quantities of waste tires not only seriously affects the human living environment, but also occupies a large amount of land resources, easily breeds mosquitoes and spreads diseases, seriously deteriorates the natural environment, and may cause fires.

[0003] The complex three-dimensional network structure of the rubber material inside tires, coupled with the large amount of fillers and softening oils added during tire production, limits the recycling of rubber materials from waste tires. However, the rubber material in tires possesses properties such as wear resistance, aging resistance, water resistance, and shock absorption. Cutting waste tires into fragments to produce rubber powder, which is then mixed with asphalt to prepare rubberized asphalt, not only transforms waste tires into valuable resources but also improves the performance of asphalt.

[0004] However, the overall performance of rubber asphalt prepared from rubber powder made from pure waste tires still needs improvement in terms of high-temperature stability, adhesion, anti-aging properties, and construction performance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a tire-based multi-element solid waste modified asphalt and its preparation method. By effectively utilizing tire-based multi-element solid waste materials such as carbon black, resin, zinc oxide, and softeners recovered from tire production, this method solves the problem of insufficient comprehensive performance of rubber asphalt prepared from rubber powder made from pure waste tires.

[0006] To achieve the above objectives, firstly, this application provides a tire multi-component solid waste modified asphalt, which is implemented using the following technical solution: A tire-grade multi-element solid waste modified asphalt comprises the following raw materials in parts by weight: 900-1300 parts asphalt, 80-120 parts waste tire rubber, 20-30 parts modified nano zinc oxide, 60-80 parts modified nano carbon black; 20-60 parts resin material. The waste tire rubber compound is obtained by mixing waste tire rubber powder and a softener at a weight ratio of (2-3):1; the waste tire rubber powder is obtained by crushing waste tires; the particle size of the waste tire rubber powder is 0.45-5.60 mm. The modified nano zinc oxide is obtained by modifying nano zinc oxide with palmitic acid and cellulose nanofibers; The modified nano-carbon black is obtained by modifying nano-carbon black with polypropylene glycol.

[0007] By adopting the above technical solution, the raw materials in this application are mainly carbon black, resin, zinc oxide, and softener from tire production, which are recycled solid waste materials. The addition of resin can effectively improve the heat resistance and cold resistance of the modified asphalt system. This application uses waste tire rubber powder and softener mixed at a weight ratio of (2-3):1 to obtain waste tire rubber compound. Since the waste tire rubber powder is obtained by crushing waste tires, the rubber powder contains crushed rubber particles and a small amount of carbon black particles. The surface of the rubber particles is uneven, and the rubber particles are easy to "pinnock" and "bite" with other particles in the modified asphalt system, which can effectively enhance the performance of asphalt.

[0008] However, the "pinning" and "biting" effects between particles make it difficult for rubber powder to disperse in the asphalt system. After mixing waste tire rubber powder and softener according to the weight ratio of this application to obtain waste tire rubber compound, the addition of softener itself can improve the performance of asphalt. After the softener and rubber powder are mixed to form waste tire rubber compound, the softener can improve the surface lubricity of rubber particles and a small amount of carbon black particles in the rubber powder, so that the waste tire rubber compound can be mixed with asphalt more fully. The rubber particles and a small amount of carbon black particles in the waste tire rubber compound can be better dispersed in the modified asphalt system, thereby further improving the performance of asphalt.

[0009] The modified nano-zinc oxide in this application is obtained by modifying nano-zinc oxide with palmitic acid and cellulose nanofibers. Nano-zinc oxide has excellent UV absorption capacity, thermal stability, and antibacterial and bacteriostatic properties. The addition of nano-zinc oxide can improve the elongation properties of the modified asphalt system and enhance the plasticity of the modified asphalt. However, nano-zinc oxide is difficult to disperse in the asphalt system. Palmitic acid has good lubricity and good light and heat stabilization effects. The addition of palmitic acid can reduce the surface tension of the modified asphalt system, thereby playing a role in reducing viscosity and increasing plasticity. Cellulose nanofibers (CNF) are linear materials with a flexible fibrous structure, a diameter in the nanometer range, a length that can reach the micrometer range, and a large aspect ratio. They can effectively improve the crack resistance of the asphalt system. The synergistic effect of the three can improve the plasticity of the modified asphalt, playing a role in increasing viscosity and reducing plasticity.

[0010] More importantly, the modified nano-zinc oxide, after being modified with palmitic acid and cellulose nanofibers, can form a linear "anchor solid" structure with an uneven and hydrophobic surface. The "anchor solid" has cellulose nanofibers as the linear skeleton and is surrounded by nano-zinc oxide particles. The surface of the "anchor solid" is modified with palmitic acid and has good hydrophobicity. It can not only be better dispersed in the modified asphalt system, but also easily "pin" and "bite" with other particles in the modified asphalt system, thereby further enhancing the performance of asphalt.

[0011] The modified carbon black in this application is obtained by modifying nano-carbon black with polypropylene glycol. When nano-carbon black is added to asphalt as a filler, it can improve the heat resistance, abrasion resistance, and UV resistance of the modified asphalt, thereby effectively improving the adhesion, deformation resistance, and aging resistance of the asphalt system. However, nano-carbon black is still difficult to disperse in the asphalt system. After modification with polypropylene glycol, polypropylene glycol is grafted onto the surface of the nano-carbon black to obtain modified carbon black, allowing carboxyl groups to be grafted onto the surface of the nano-carbon black. This enables the modified nano-carbon black to be better dispersed in the asphalt system, thereby further improving the performance of the modified asphalt system.

[0012] In addition, the nano zinc oxide, after being modified with palmitic acid, has an increased particle size, forming a good gradation with the modified nano carbon black and waste tire rubber powder with a particle size of 0.45-5.60 mm in the raw materials, which can further improve the comprehensive performance of modified asphalt.

[0013] More importantly, while the addition of nano-carbon black can improve the adhesion, deformation resistance, and aging resistance of asphalt systems, it reduces the elongation of the asphalt system. Modified nano-carbon black obtained by modifying nano-carbon black with polypropylene glycol has carboxyl groups on its surface, and modified nano-zinc oxide obtained by modifying nano-zinc oxide with palmitic acid and cellulose nanofibers has carbonyl groups on its surface. The hydroxyl groups in the carboxyl groups form hydrogen bonds with the carbonyl groups, allowing the modified nano-carbon black and modified nano-zinc oxide to disperse together in the asphalt system. Furthermore, the modified nano-zinc oxide can form a linear "anchor" structure with an uneven and hydrophobic surface. The modified nano-carbon black can be "embedded" in the grooves of this "anchor" structure under the influence of the hydroxyl and carbonyl groups, further enhancing the "co-existence" effect between the modified nano-carbon black and modified nano-zinc oxide. The presence of modified nano-zinc oxide can compensate for the reduced elongation of the asphalt system caused by the addition of modified nano-carbon black. Therefore, the combined effect of modified nano-zinc oxide and modified nano-carbon black can further improve the overall performance of the modified asphalt system.

[0014] In summary, the tire multi-element solid waste modified asphalt obtained by the specific formulation of this application can effectively utilize the tire multi-element solid waste materials such as carbon black, resin, zinc oxide and softener recovered from tire production, and improve the high-temperature stability, adhesion, anti-aging and workability of the modified asphalt system.

[0015] Furthermore, the preparation method of the modified nano zinc oxide includes the following steps: 15-20 kg of palmitic acid is added to 90-100 kg of diethyl ether to obtain a base solution. After stirring the base solution for 20-40 min, 100-120 kg of nano-zinc oxide and 1-1.5 kg of cellulose nanofibers are added to the base solution to obtain a mixed solution. The mixed solution is heated to 75-85℃ and stirred continuously for 6-8 h, then filtered, dried at 50-60℃ for 1-2 h, and ground to obtain modified nano-zinc oxide; the nano-zinc oxide has a particle size of 50-100 nm. By adopting the above technical solution, palmitic acid can be grafted onto the surface of nano zinc oxide, resulting in lipophilic groups on the surface of nano zinc oxide, which in turn allows the modified nano zinc oxide to be better dispersed in the modified asphalt system.

[0016] Furthermore, the preparation method of the modified nano-carbon black includes the following steps: Preparation of oxidized nano-carbon black: 5-10 kg of nano-carbon black is added to 50-100 L of nitric acid to obtain a suspension. The suspension is heated and stirred in a water bath at 95-100℃ for 4.5-5.5 h. After centrifugation, it is washed with water 3-5 times and dried at 50-60℃ to obtain oxidized nano-carbon black. Preparation of modified nano-carbon black: 10-12 kg of oxidized nano-carbon black, 8-10 kg of polypropylene glycol, and 0.1-0.3 kg of aminosulfonic acid are added to 20-30 L of toluene and stirred at 110-120 °C for 6-8 h. After centrifugation, the mixture is washed with water 3-5 times and dried at 50-60 °C to obtain modified nano-carbon black.

[0017] By adopting the above technical solution, polypropylene glycol can be grafted onto the surface of carbon nanofiber, resulting in oleophilic groups on the surface of carbon nanofiber, which in turn allows the modified carbon nanofiber to be better dispersed in the modified asphalt system.

[0018] Furthermore, the nano carbon black is selected from N330 nano carbon black.

[0019] By adopting the above technical solution, N330 nano carbon black Furthermore, the asphalt is petroleum asphalt or coal tar pitch.

[0020] Furthermore, the softener is a cycloalkane oil or an aromatic oil.

[0021] By adopting the above technical solutions, cycloalkane oil or aromatic oil can be added to the asphalt system as a softener, which can effectively improve the low-temperature crack resistance of the asphalt system, effectively adjust the softening point and workability of the asphalt system, and enhance the durability and anti-aging properties of the asphalt system.

[0022] Furthermore, the resin material is polyethylene, polypropylene, or rosin resin.

[0023] Secondly, this application provides a method for preparing tire multi-element solid waste modified asphalt, which employs the following technical method: A method for preparing tire-grade multi-element solid waste modified asphalt, characterized by comprising the following steps: Heat the asphalt to 120-140℃, and while stirring, add waste tire rubber, resin materials, modified nano zinc oxide and modified carbon black to the asphalt. Continue stirring for 20-40 minutes to obtain tire multi-element solid waste modified asphalt.

[0024] By adopting the above technical solution, the asphalt is first heated to make it sufficiently fluid, and then other raw materials are added while stirring, which allows the other raw materials to be fully dispersed in the asphalt system, thereby effectively improving the performance of the modified asphalt system.

[0025] Further, the asphalt is heated to 120-140℃, and the modified nano zinc oxide and modified carbon black are mixed and stirred for 10-20 minutes to obtain modified filler. While stirring, waste tire rubber, resin material and modified filler are added to the asphalt, and stirring is continued for 20-40 minutes to obtain tire multi-element solid waste modified asphalt.

[0026] By adopting the above technical solution, the modified nano zinc oxide and modified carbon black are mixed and stirred into a modified filler before being added to the modified asphalt system. This can further enhance the synergistic effect of the modified nano zinc oxide and modified carbon black, thereby further improving the overall performance of the modified asphalt system.

[0027] Compared with the prior art, this application has the following technical effects: 1. The raw materials used in this application are mainly carbon black, resin, zinc oxide, and softener, which are recycled solid waste materials from tire production. The addition of resin can effectively improve the heat resistance and cold resistance of the modified asphalt system. This application uses waste tire rubber powder and softener mixed at a weight ratio of (2-3):1 to obtain waste tire rubber compound. Since the waste tire rubber powder is obtained by crushing waste tires, the rubber powder contains crushed rubber particles and a small amount of carbon black particles. The surface of the rubber particles is uneven, and the rubber particles are easy to "pinnock" and "bite" with other particles in the modified asphalt system, which can effectively enhance the performance of asphalt.

[0028] However, the "pinning" and "biting" effects between particles make it difficult for rubber powder to disperse in the asphalt system. After mixing waste tire rubber powder and softener according to the weight ratio of this application to obtain waste tire rubber compound, the addition of softener itself can improve the performance of asphalt. After the softener and rubber powder are mixed to form waste tire rubber compound, the softener can improve the surface lubricity of rubber particles and a small amount of carbon black particles in the rubber powder, so that the waste tire rubber compound can be mixed with asphalt more fully. The rubber particles and a small amount of carbon black particles in the waste tire rubber compound can be better dispersed in the modified asphalt system, thereby further improving the performance of asphalt.

[0029] The modified nano-zinc oxide in this application is obtained by modifying nano-zinc oxide with palmitic acid and cellulose nanofibers. Nano-zinc oxide has excellent UV absorption capacity, thermal stability, and antibacterial and bacteriostatic properties. The addition of nano-zinc oxide can improve the elongation properties of the modified asphalt system and enhance the plasticity of the modified asphalt. However, nano-zinc oxide is difficult to disperse in the asphalt system. Palmitic acid has good lubricity and good light and heat stabilization effects. The addition of palmitic acid can reduce the surface tension of the modified asphalt system, thereby playing a role in reducing viscosity and increasing plasticity. Cellulose nanofibers (CNF) are linear materials with a flexible fibrous structure, a diameter in the nanometer range, a length that can reach the micrometer range, and a large aspect ratio. They can effectively improve the crack resistance of the asphalt system. The synergistic effect of the three can improve the plasticity of the modified asphalt, playing a role in increasing viscosity and reducing plasticity.

[0030] More importantly, the modified nano-zinc oxide, after being modified with palmitic acid and cellulose nanofibers, can form a linear "anchor solid" structure with an uneven and hydrophobic surface. The "anchor solid" has cellulose nanofibers as the linear skeleton and is surrounded by nano-zinc oxide particles. The surface of the "anchor solid" is modified with palmitic acid and has good hydrophobicity. It can not only be better dispersed in the modified asphalt system, but also easily "pin" and "bite" with other particles in the modified asphalt system, thereby further enhancing the performance of asphalt.

[0031] The modified carbon black in this application is obtained by modifying nano-carbon black with polypropylene glycol. When nano-carbon black is added to asphalt as a filler, it can improve the heat resistance, abrasion resistance, and UV resistance of the modified asphalt, thereby effectively improving the adhesion, deformation resistance, and aging resistance of the asphalt system. However, nano-carbon black is still difficult to disperse in the asphalt system. After modification with polypropylene glycol, polypropylene glycol is grafted onto the surface of the nano-carbon black to obtain modified carbon black, allowing carboxyl groups to be grafted onto the surface of the nano-carbon black. This enables the modified nano-carbon black to be better dispersed in the asphalt system, thereby further improving the performance of the modified asphalt system.

[0032] In addition, the nano zinc oxide, after being modified with palmitic acid, has an increased particle size, forming a good gradation with the modified nano carbon black and waste tire rubber powder with a particle size of 0.45-5.60 mm in the raw materials, which can further improve the comprehensive performance of modified asphalt.

[0033] More importantly, while the addition of nano-carbon black can improve the adhesion, deformation resistance, and aging resistance of asphalt systems, it reduces the elongation of the asphalt system. Modified nano-carbon black obtained by modifying nano-carbon black with polypropylene glycol has carboxyl groups on its surface, and modified nano-zinc oxide obtained by modifying nano-zinc oxide with palmitic acid has carbonyl groups on its surface. The hydroxyl groups in the carboxyl groups form hydrogen bonds with the carbonyl groups, allowing the modified nano-carbon black and modified nano-zinc oxide to disperse together in the asphalt system. Furthermore, the modified nano-zinc oxide can form a linear "anchor" structure with an uneven and hydrophobic surface. The modified nano-carbon black can be "embedded" in the grooves of this "anchor" structure under the influence of the hydroxyl and carbonyl groups, further enhancing the "co-existence" effect between the modified nano-carbon black and modified nano-zinc oxide. The presence of modified nano-zinc oxide can compensate for the reduced elongation of the asphalt system caused by the addition of modified nano-carbon black. Therefore, the combined effect of modified nano-zinc oxide and modified nano-carbon black can further improve the overall performance of the modified asphalt system.

[0034] In summary, the tire multi-element solid waste modified asphalt obtained by the specific formulation of this application can effectively utilize the tire multi-element solid waste materials such as carbon black, resin, zinc oxide and softener recovered from tire production, and improve the high-temperature stability, adhesion, anti-aging and workability of the modified asphalt system.

[0035] 2. After palmitic acid modification, palmitic acid can be grafted onto the surface of nano-zinc oxide, resulting in lipophilic groups on the surface. This allows the modified nano-zinc oxide to be better dispersed in the modified asphalt system, thereby improving the performance of the modified asphalt. Similarly, after polypropylene glycol modification, polypropylene glycol can be grafted onto the surface of carbon black, resulting in lipophilic groups on the carbon black surface. This also allows the modified carbon black to be better dispersed in the modified asphalt system, thereby improving the performance of the modified asphalt.

[0036] 3. Adding naphthenic oil or aromatic oil as a softener to the asphalt system can effectively improve the low-temperature crack resistance of the asphalt system, effectively adjust the softening point and workability of the asphalt system, and enhance the durability and anti-aging properties of the asphalt system.

[0037] 4. In the preparation method of this application, the asphalt is first heated to make it have sufficient fluidity, and then other raw materials are added while stirring, which can make the other raw materials fully dispersed in the asphalt system, thereby effectively improving the performance of the modified asphalt system.

[0038] 5. In the preparation method of this application, the modified nano zinc oxide and modified carbon black are mixed and stirred to form a modified filler before being added to the modified asphalt system. This can further enhance the synergistic effect of the modified nano zinc oxide and modified carbon black, thereby further improving the comprehensive performance of the modified asphalt system.

[0039] In summary, this application discloses a tire-based multi-element solid waste modified asphalt and its preparation method. By effectively utilizing tire-based multi-element solid waste materials such as carbon black, resin, zinc oxide, and softeners recovered from tire production, the high-temperature stability, adhesion, anti-aging properties, and workability of the modified asphalt system are effectively improved, solving the problem of insufficient comprehensive performance of rubber asphalt prepared from rubber powder made from pure waste tires. Detailed Implementation

[0040] In this application, the asphalt used is No. 70 petroleum asphalt, the waste tire rubber powder has a particle size of 0.45-5.60mm, the nano carbon black used is N330 nano carbon black, the nano zinc oxide has a particle size of 50-100nm, and the cellulose nanofiber is TL-011 nano cellulose-based fiber (solid content 1.5%-3%) from Nanjing Tianlu Nanotechnology Co., Ltd.

[0041] Preparation example of modified nano zinc oxide Preparation Example 1 A method for preparing modified nano zinc oxide includes the following steps: 15 kg of palmitic acid was added to 90 kg of diethyl ether to obtain a base solution. After stirring the base solution for 20 min, 100 kg of nano zinc oxide and 1 kg of cellulose nanofibers were added to the base solution to obtain a mixed solution. The mixed solution was heated to 75 °C and stirred continuously for 6 h, then filtered, dried at 50 °C for 1 h, and ground to obtain modified nano zinc oxide.

[0042] Preparation Example 2 A method for preparing modified nano zinc oxide includes the following steps: 20 kg of palmitic acid was added to 100 kg of diethyl ether to obtain a base solution. After stirring the base solution for 40 min, 120 kg of nano zinc oxide and 1.5 kg of cellulose nanofibers were added to the base solution to obtain a mixed solution. The mixed solution was heated to 85 °C and stirred continuously for 8 h, then filtered, dried at 60 °C for 2 h, and ground to obtain modified nano zinc oxide.

[0043] Preparation Example 3 A method for preparing modified nano zinc oxide includes the following steps: 18 kg of palmitic acid was added to 95 kg of diethyl ether to obtain a base solution. After stirring the base solution for 30 min, 110 kg of nano zinc oxide and 1.2 kg of cellulose nanofibers were added to the base solution to obtain a mixed solution. The mixed solution was heated to 80 °C and stirred continuously for 7 h, then filtered, dried at 55 °C for 2 h, and ground to obtain modified nano zinc oxide.

[0044] Preparation example of modified nano carbon black Preparation Example 4 A method for preparing modified nano-carbon black includes the following steps: Preparation of oxidized nano-carbon black: 5 kg of nano-carbon black was added to 50 L of nitric acid to obtain a suspension. The suspension was heated and stirred in a water bath at 95 °C for 4.5 h. After centrifugation, the nano-carbon black was washed three times with water and dried at 50 °C to obtain oxidized nano-carbon black. Preparation of modified nano-carbon black: 10 kg of oxidized nano-carbon black, 8 kg of polypropylene glycol, and 0.1 kg of aminosulfonic acid were added to 20 L of toluene and stirred at 110 °C for 6 h. After centrifugation, the mixture was washed three times with water and dried at 50 °C to obtain modified nano-carbon black.

[0045] Preparation Example 5 A method for preparing modified nano-carbon black includes the following steps: Preparation of oxidized nano-carbon black: 10 kg of nano-carbon black was added to 100 L of nitric acid to obtain a suspension. The suspension was heated and stirred in a water bath at 100 °C for 5.5 h. After centrifugation, it was washed with water 5 times and dried at 60 °C to obtain oxidized nano-carbon black. Preparation of modified nano-carbon black: 12 kg of oxidized nano-carbon black, 10 kg of polypropylene glycol and 0.3 kg of aminosulfonic acid were added to 30 L of toluene, stirred at 120 °C for 8 h, centrifuged and washed with water 5 times, and dried at 60 °C to obtain modified nano-carbon black.

[0046] Preparation Example 6 A method for preparing modified nano-carbon black includes the following steps: Preparation of oxidized nano-carbon black: 8 kg of nano-carbon black was added to 80 L of nitric acid to obtain a suspension. The suspension was heated and stirred in a water bath at 100 °C for 5 h. After centrifugation, it was washed with water 4 times and dried at 55 °C to obtain oxidized nano-carbon black. Preparation of modified nano-carbon black: 11 kg of oxidized nano-carbon black, 9 kg of polypropylene glycol and 0.2 kg of aminosulfonic acid were added to 25 L of toluene, stirred at 115 °C for 7 h, centrifuged and washed with water 4 times, and dried at 55 °C to obtain modified nano-carbon black.

[0047] Comparative preparation examples of modified nano zinc oxide Comparative Preparation Example 1 A method for preparing modified nano zinc oxide is carried out according to the method in Preparation Example 3, except that 1.2 kg of cellulose nanofibers in the raw materials are replaced by an equal amount of nano zinc oxide.

[0048] Example Example 1 A method for preparing tire-grade multi-element solid waste modified asphalt includes the following steps: Asphalt was heated to 120℃, and while stirring, 120kg of waste tire rubber, 20kg of resin material, 20kg of modified nano zinc oxide, and 60kg of modified carbon black were added to 900kg of asphalt. After stirring continuously for 20 minutes, tire multi-element solid waste modified asphalt was obtained. The waste tire rubber compound is obtained by mixing waste tire rubber powder and softener in a weight ratio of 2:1. The modified nano zinc oxide was prepared by the method in Preparation Example 1, and the modified nano carbon black was prepared by the method in Preparation Example 4. The softener used is cycloalkane oil; the resin material is polyethylene; and the stirring method is high-speed shearing.

[0049] Example 2 A method for preparing tire-grade multi-element solid waste modified asphalt includes the following steps: Asphalt was heated to 140℃, and while stirring, 80kg of waste tire rubber, 60kg of resin material, 30kg of modified nano zinc oxide, and 80kg of modified nano carbon black were added to 1300kg of asphalt. After stirring continuously for 40 minutes, tire multi-element solid waste modified asphalt was obtained. The waste tire rubber compound is obtained by mixing waste tire rubber powder and softener in a weight ratio of 3:1. The modified nano zinc oxide was prepared by the method in Preparation Example 2, and the modified nano carbon black was prepared by the method in Preparation Example 5. The softener used is cycloalkane oil; the resin material is polyethylene; and the stirring method is high-speed shearing. Example 3 A method for preparing tire-grade multi-element solid waste modified asphalt includes the following steps: Asphalt was heated to 130℃, and while stirring, 105kg of waste tire rubber, 40kg of resin material, 25kg of modified nano zinc oxide, and 70kg of modified nano carbon black were added to 1000kg of asphalt. After stirring continuously for 30 minutes, tire multi-element solid waste modified asphalt was obtained. The waste tire rubber compound is obtained by mixing waste tire rubber powder and softener at a weight ratio of 2.5:1. The modified nano zinc oxide was prepared by the method in Preparation Example 3, and the modified nano carbon black was prepared by the method in Preparation Example 6. The softener used is cycloalkane oil; the resin material is polyethylene; and the stirring method is high-speed shearing.

[0050] Example 4 A method for preparing tire multi-element solid waste modified asphalt is carried out according to the method in Example 3, except that the softener in the raw material is aromatic oil.

[0051] Example 5 A method for preparing tire multi-element solid waste modified asphalt is carried out according to the method in Example 4, except that the resin material in the raw material is rosin resin.

[0052] Example 6 A method for preparing tire-grade multi-element solid waste modified asphalt includes the following steps: Asphalt was heated to 130℃. 25 kg of modified nano-zinc oxide and 70 kg of modified nano-carbon black were mixed and stirred for 15 minutes to obtain a modified filler. While stirring, 105 kg of waste tire rubber, 40 kg of resin material, and the modified filler were added to 1000 kg of asphalt. Stirring continued for 30 minutes to obtain tire-derived multi-element solid waste modified asphalt. The waste tire rubber compound is obtained by mixing waste tire rubber powder and softener at a weight ratio of 2.5:1. The modified nano zinc oxide was prepared by the method in Preparation Example 3, and the modified nano carbon black was prepared by the method in Preparation Example 6. The softener is an aromatic oil; the resin material is rosin resin; and the stirring method is high-speed shearing.

[0053] Comparative Example Comparative Example 1 A method for preparing tire-derived multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that the waste tire rubber compound, resin material, modified nano zinc oxide and modified carbon black in the raw materials are all replaced by waste tire rubber powder in equal amounts.

[0054] Comparative Example 2 A method for preparing tire-derived multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that 105 kg of waste tire rubber compound is replaced by 75 kg of waste tire rubber powder and 30 kg of aromatic oil, 25 kg of modified nano zinc oxide is replaced by 21.5 kg of nano zinc oxide and 3.5 kg of palmitic acid, and 70 kg of modified nano carbon black is replaced by an equal amount of nano carbon black.

[0055] Comparative Example 3 A method for preparing tire multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that 25 kg of modified nano zinc oxide in the raw materials is replaced by 21.2 kg of nano zinc oxide, 3.5 kg of palmitic acid and 0.3 kg of cellulose nanofibers.

[0056] Comparative Example 4 A method for preparing tire multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that 70 kg of modified nano carbon black in the raw materials is replaced by an equal amount of nano carbon black.

[0057] Comparative Example 5 A method for preparing tire-derived multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that 105 kg of waste tire rubber compound is replaced by 75 kg of waste tire rubber powder and 30 kg of aromatic oil in the raw materials.

[0058] Comparative Example 6 A method for preparing tire multi-element solid waste modified asphalt is carried out according to the method in Example 6, except that the modified nano zinc oxide in the raw material is prepared by the method in Comparative Preparation Example 1.

[0059] Performance testing The above embodiments and comparative examples underwent the following performance tests, and the test results are shown in the table below: The penetration, ductility, and softening point of the modified asphalt prepared in the above examples and comparative examples were tested using the test methods in JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The test results are shown in Table 1.

[0060] Table 1: Combining the data from Examples 4 and 1-3 in Table 1, it can be seen that the overall performance of the modified asphalt in Example 4 is slightly improved compared to that in Examples 1-3. The difference between Example 4 and Examples 1-3 is that the softener in Example 4 is aromatic oil. This indicates that by using aromatic oil as a softener in the modified asphalt system in the formulation disclosed in this application, the overall performance of the modified asphalt can be further improved.

[0061] Combining the data from Examples 5 and 4 in Table 1, it can be seen that the overall performance of the modified asphalt in Example 5 is slightly improved compared to that in Example 4. The difference between the two is that the resin material in Example 5 is rosin resin, indicating that the use of rosin resin as a resin material in the modified asphalt system in the formulation disclosed in this application can further improve the overall performance of the modified asphalt.

[0062] Combining the data from Examples 6 and 5 in Table 1, it can be seen that the overall performance of the modified asphalt in Example 6 is slightly improved compared to that in Example 5. The difference between the two is that in Example 6, when preparing the modified asphalt, nano zinc oxide and modified nano carbon black are first mixed into a modified filler before being added to the asphalt. This indicates that in the preparation method disclosed in this application, mixing nano zinc oxide and modified nano carbon black into a modified filler before adding the modified filler and other fillers to the asphalt can further improve the overall performance of the modified asphalt.

[0063] Combining the data from Example 6 and Comparative Example 1 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 1. This is because the modified asphalt in Comparative Example 1 was prepared solely from pure waste tire rubber powder, and the raw materials did not include the waste tire rubber compound, modified nano zinc oxide, modified nano carbon black, and resin materials disclosed in this application. In contrast, the modified asphalt in Example 6 was prepared by mixing waste tire rubber powder and a softener at a weight ratio of (2-3):1 to obtain waste tire rubber compound. Since the waste tire rubber powder is obtained by crushing waste tires, the rubber powder contains crushed rubber particles and a small amount of carbon black particles. The surface of the rubber particles is uneven, and the rubber particles are prone to "pinning" and "biting" with other particles in the modified asphalt system, which can effectively enhance the performance of the asphalt.

[0064] However, the "pinning" and "biting" effects between particles make it difficult for rubber powder to disperse in the asphalt system. After mixing waste tire rubber powder and softener according to the weight ratio of this application to obtain waste tire rubber compound, the addition of softener itself can improve the performance of asphalt. After the softener and rubber powder are mixed to form waste tire rubber compound, the softener can improve the surface lubricity of rubber particles and a small amount of carbon black particles in the rubber powder, so that the waste tire rubber compound can be mixed with asphalt more fully. The rubber particles and a small amount of carbon black particles in the waste tire rubber compound can be better dispersed in the modified asphalt system, thereby further improving the performance of asphalt.

[0065] In Example 6, the modified nano-zinc oxide was obtained by modifying nano-zinc oxide with palmitic acid and cellulose nanofibers. The addition of nano-zinc oxide can improve the elongation properties of the modified asphalt system and enhance its plasticity, but nano-zinc oxide is difficult to disperse in the asphalt system. Palmitic acid has good lubricity and good light and heat stability; its addition can reduce the surface tension of the modified asphalt system, thereby reducing viscosity and increasing plasticity. Cellulose nanofibers (CNF) are linear materials with a flexible fibrous structure, nanometer-scale diameter, micrometer-scale length, and large aspect ratio, which can effectively improve the crack resistance of the asphalt system. The synergistic effect of these three materials can improve the plasticity of the modified asphalt, thus increasing viscosity and reducing plasticity.

[0066] More importantly, the modified nano-zinc oxide, after being modified with palmitic acid and cellulose nanofibers, can form a linear "anchor solid" structure with an uneven and hydrophobic surface. The "anchor solid" has cellulose nanofibers as the linear skeleton and is surrounded by nano-zinc oxide particles. The surface of the "anchor solid" is modified with palmitic acid and has good hydrophobicity. It can not only be better dispersed in the modified asphalt system, but also easily "pin" and "bite" with other particles in the modified asphalt system, thereby further enhancing the performance of asphalt.

[0067] In Example 6, the modified carbon black was obtained by modifying carbon black with polypropylene glycol. Carbon black, when added to asphalt as a filler, effectively improves the adhesion, resistance to deformation, and anti-aging properties of the asphalt system. However, carbon black is still difficult to disperse in the asphalt system. After modification with polypropylene glycol, polypropylene glycol is grafted onto the surface of the carbon black to obtain modified carbon black. This allows carboxyl groups to be grafted onto the carbon black surface, enabling the modified carbon black to be better dispersed in the asphalt system, thereby further improving the performance of the modified asphalt system.

[0068] In addition, the nano zinc oxide, after being modified with palmitic acid, has an increased particle size, forming a good gradation with the modified nano carbon black and waste tire rubber powder with a particle size of 0.45-5.60 mm in the raw materials, which can further improve the comprehensive performance of modified asphalt.

[0069] More importantly, while the addition of carbon black can improve the adhesion, deformation resistance, and aging resistance of the asphalt system, it reduces its elongation. Modified carbon black obtained by modifying carbon black with polypropylene glycol has carboxyl groups on its surface, and modified nano-zinc oxide obtained by modifying nano-zinc oxide with palmitic acid has carbonyl groups on its surface. The hydroxyl groups in the carboxyl groups form hydrogen bonds with the carbonyl groups, allowing the modified carbon black and modified nano-zinc oxide to disperse together in the asphalt system. Furthermore, the modified nano-zinc oxide can form a linear "anchor" structure with an uneven and hydrophobic surface. The modified carbon black can be "embedded" in the grooves of this "anchor" structure under the influence of the hydroxyl and carbonyl groups, further enhancing the "co-existence" effect between the modified carbon black and modified nano-zinc oxide. The presence of modified nano-zinc oxide can compensate for the reduced elongation of the asphalt system caused by the addition of carbon black. Therefore, the combined effect of modified nano-zinc oxide and modified carbon black can further improve the overall performance of the modified asphalt system.

[0070] In summary, the modified asphalt in Example 6 exhibits superior high-temperature stability, adhesion, anti-aging properties, and workability. This demonstrates that the tire multi-element solid waste modified asphalt obtained from the specific formulation of this application can effectively utilize tire multi-element solid waste materials such as carbon black, resin, zinc oxide, and softeners recovered from tire production, thereby improving the high-temperature stability, adhesion, anti-aging properties, and workability of the modified asphalt system.

[0071] Combining the data from Example 6 and Comparative Example 2 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 2. This is because, while the modified asphalt in Comparative Example 2 contains palmitic acid, zinc oxide, carbon black, waste tire rubber powder, and softeners—multi-component solid waste materials recovered from tire production—compared to Example 6, the modified asphalt in Comparative Example 2 directly adds these multi-component solid waste materials as fillers to the asphalt, without including the waste tire rubber compound, modified nano-zinc oxide, and modified nano-carbon black disclosed in this application. This indicates that the addition of waste tire rubber compound, modified nano-zinc oxide, and modified nano-carbon black in Example 6 effectively improves the overall performance of the modified asphalt.

[0072] Combining the data from Example 6 and Comparative Example 3 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 3. This is because, in Comparative Example 3, the modified nano-zinc oxide in the raw materials was replaced by palmitic acid and nano-zinc oxide in equal amounts. In contrast to Example 6, the raw materials in Comparative Example 3 did not contain the modified nano-zinc oxide disclosed in this application. This demonstrates that the addition of modified nano-zinc oxide in Example 6 effectively improves the overall performance of the modified asphalt. Combining the data from Example 6 and Comparative Example 4 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 4. This is because, in Comparative Example 4, the modified nano-carbon black was replaced by an equal amount of nano-carbon black in the raw materials, whereas the raw materials in Comparative Example 4 did not contain the modified nano-carbon black disclosed in this application. This demonstrates that the addition of modified nano-carbon black in Example 6 effectively improves the overall performance of the modified asphalt.

[0073] Combining the data from Example 6 and Comparative Example 5 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 5. This is because, in Comparative Example 5, the waste tire rubber compound was replaced by waste tire rubber powder and a softener in equal amounts in the raw materials. In contrast, the raw materials in Comparative Example 5 did not contain the waste tire rubber compound disclosed in this application. This demonstrates that the addition of waste tire rubber compound in Example 6 effectively improves the overall performance of the modified asphalt.

[0074] Combining the data from Example 6 and Comparative Example 6 in Table 1, it can be seen that the modified asphalt in Example 6 exhibits significantly better penetration, ductility, and softening point than the modified asphalt in Comparative Example 6. This is because the modified nano-zinc oxide in the raw material of Comparative Example 6 is only modified with palmitic acid, and no cellulose nanofibers are added. Compared to Example 6, the raw material in Comparative Example 5 does not contain the modified nano-zinc oxide disclosed in this application, resulting in a lack of an "anchoring body" structure in the modified asphalt system. This indicates that the addition of modified nano-zinc oxide modified with palmitic acid and cellulose nanofibers to the asphalt system in Example 6 effectively improves the overall performance of the modified asphalt.

[0075] In summary, based on the data in Table 1 of Example 6 and Comparative Examples 3-6, and the differences between Example 6 and Comparative Examples 3-6, it can be demonstrated that the waste tire rubber compound, modified nano zinc oxide, and modified nano carbon black disclosed in this application, when formulated according to the proportions disclosed in this application, can effectively improve the overall performance of modified asphalt.

[0076] The specific embodiments described in this application are merely illustrative of the application and are not intended to limit it. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A tire-grade multi-element solid waste modified asphalt, characterized in that, The ingredients include the following parts by weight: 900-1300 parts asphalt, 80-120 parts waste tire rubber, 20-30 parts modified nano zinc oxide, 60-80 parts modified nano carbon black; 20-60 parts resin material. The waste tire rubber compound is obtained by mixing waste tire rubber powder and a softener at a weight ratio of (2-3):1; the waste tire rubber powder is obtained by crushing waste tires; the particle size of the waste tire rubber powder is 0.45-5.60 mm. The modified nano zinc oxide is obtained by modifying nano zinc oxide with palmitic acid and cellulose nanofibers; The modified nano-carbon black is obtained by modifying nano-carbon black with polypropylene glycol.

2. The tire multi-element solid waste modified asphalt as described in claim 1, characterized in that, The preparation method of the modified nano zinc oxide includes the following steps: 15-20 kg of palmitic acid is added to 90-100 kg of diethyl ether to obtain a base solution. After stirring the base solution for 20-40 min, 100-120 kg of nano zinc oxide and 1-1.5 kg of cellulose nanofibers are added to the base solution to obtain a mixed solution. The mixed solution is heated to 75-85℃ and stirred continuously for 6-8 h, then filtered, dried at 50-60℃ for 1-2 h, and ground to obtain modified nano zinc oxide. The nano zinc oxide has a particle size of 50-100 nm.

3. The tire multi-element solid waste modified asphalt as described in claim 1, characterized in that, The preparation method of the modified nano-carbon black includes the following steps: Preparation of oxidized nano-carbon black: 5-10 kg of nano-carbon black is added to 50-100 L of nitric acid to obtain a suspension. The suspension is heated and stirred in a water bath at 95-100℃ for 4.5-5.5 h. After centrifugation, it is washed with water 3-5 times and dried at 50-60℃ to obtain oxidized nano-carbon black. Preparation of modified nano-carbon black: Add 10-12 kg of oxidized nano-carbon black, 8-10 kg of polypropylene glycol, and 0.1-0.3 kg of aminosulfonic acid to 20-30 L of toluene, stir at 110-120℃ for 6-8 h, centrifuge, wash with water 3-5 times, and dry at 50-60℃ to obtain modified nano-carbon black.

4. The tire multi-element solid waste modified asphalt as described in claim 3, characterized in that, The nano carbon black is N330 carbon black.

5. The tire multi-element solid waste modified asphalt as described in claim 1, characterized in that, The asphalt is petroleum asphalt or coal tar pitch.

6. The tire multi-element solid waste modified asphalt as described in claim 1, characterized in that, The softener is a cycloalkane oil or an aromatic oil.

7. The tire multi-element solid waste modified asphalt as described in claim 1, characterized in that, The resin material is polyethylene, polypropylene, or rosin resin.

8. As claimed in claim 1 A method for preparing tire multi-element solid waste modified asphalt according to any one of the seven claims, characterized in that, Includes the following steps: Heat the asphalt to 120-140℃, and while stirring, add waste tire rubber, resin materials, modified nano zinc oxide and modified nano carbon black to the asphalt. Continue stirring for 20-40 minutes to obtain tire multi-element solid waste modified asphalt.

9. A method for preparing tire multi-element solid waste modified asphalt as described in claim 8: heating asphalt to 120-140℃, mixing the modified nano zinc oxide and modified nano carbon black and stirring for 10-20 minutes to obtain modified filler, adding waste tire rubber, resin material and modified filler to the asphalt while stirring, and continuing to stir for 20-40 minutes to obtain tire multi-element solid waste modified asphalt.

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