An asphalt aging repair agent and its preparation and application method

Abstract

This application belongs to the field of road maintenance technology and discloses an asphalt aging repair agent and its preparation and application method. The asphalt aging repair agent of this application has low viscosity, good stability, excellent adhesion, wear resistance, penetration and waterproof performance, good compatibility, and is suitable for high-level complex service environments. When used, it is sprayed on-site without the need for milling the asphalt, so as to achieve the purpose of quickly repairing aged asphalt under low temperature conditions on-site. It is convenient, quick and easy to construct. The preparation process is simple, the equipment requirements are low and the economy is good.

Description

Technical Field

[0001] This application belongs to the field of road maintenance technology, specifically relating to an asphalt aging repair agent and its preparation and application methods. Background Technology

[0002] Petroleum asphalt, with its excellent adhesion, waterproofing, and durability, is widely used in road engineering, especially in the construction of high-grade highways. However, during long-term service, asphalt pavements are continuously subjected to the coupled effects of complex factors such as ultraviolet radiation, oxygen, heat, and dynamic vehicle loads. These external factors cause a series of irreversible physicochemical changes in asphalt. For example, the light components such as aromatics and saturated components in asphalt undergo irreversible transformation into heavy components such as resins and asphaltenes through oxidation and volatilization, leading to asphalt aging. In addition, the adsorption of asphalt by the micropores of aggregates also promotes the aging process, causing the asphalt to harden, become more brittle, lose ductility, and even develop microcracks. These changes are macroscopically manifested as a decrease in asphalt penetration, an increase in softening point, and a decrease in ductility. Aging of asphalt binder is one of the fundamental causes of various pavement diseases. Aging asphalt pavements have reduced flexibility and are more prone to early damage such as microcracks, block cracking, and loosening under repeated temperature stress and traffic loads. These microcracks further provide pathways for moisture and air intrusion, exacerbating internal structural damage, creating a vicious cycle, and severely shortening the service life of the pavement. Currently, the commonly used repair techniques for pavement damage caused by asphalt aging are milling and repaving or in-situ hot (cold) recycling. While these methods can restore pavement performance to some extent, such recycling treatments require large investment, long construction periods, are time-consuming and labor-intensive, and necessitate prolonged traffic disruptions, significantly reducing economic and social benefits. In recent years, some fog-seal or penetrating recycling repair agents have emerged to attempt to restore the performance of aged asphalt in situ through spraying.

[0003] However, existing repair agents often suffer from insufficient penetration depth and limited functionality in practical applications. Some products only replenish oil to soften asphalt, offering limited benefits for cementitious network reconstruction. The improvement in high-temperature stability and low-temperature crack resistance of the repaired pavement is not significant, and most lack long-lasting anti-aging components, resulting in poor durability under thermo-oxidative conditions. Summary of the Invention

[0004] The purpose of this application is to address the problems of the prior art by providing an asphalt aging repair agent and its preparation and application methods.

[0005] To solve the technical problem, the technical solution of this application is: This application provides an asphalt aging repair agent, which is composed of the following components in parts by weight: 25-35 parts waste cooking oil, 21-23 parts waste rubber powder, 8-11 parts hexamethylene diisocyanate, 3-5 parts bisphenol A diglycidyl ether, 3-5 parts polyvinyl alcohol, 5-9 parts sulfolane, 5-8 parts ultrafine cement, 2-3 parts hindered amine stabilizer, 2-3 parts nano titanium dioxide, and 5-10 parts water.

[0006] Preferably, it consists of the following components in parts by mass: 35 parts waste cooking oil, 23 parts waste rubber powder, 11 parts hexamethylene diisocyanate, 5 parts bisphenol A diglycidyl ether, 5 parts polyvinyl alcohol, 9 parts sulfolane, 8 parts ultrafine cement, 3 parts hindered amine stabilizer, 3 parts nano titanium dioxide, and 9 parts water.

[0007] Preferably, the waste cooking oil has an acid value ≤5 mg KOH / g, a moisture content ≤0.1%, and after dehydration and impurity removal, the saturated fatty acid content is 20-40 wt% and the unsaturated fatty acid content is 60-80 wt%.

[0008] Preferably, the waste rubber powder has a particle size of 0.10-0.15 mm and has undergone microwave desulfurization treatment at a frequency of 910-920 MHz for 4-6 min.

[0009] Preferably, the content of isocyanate groups in the hexamethylene diisocyanate is 48-50%, the epoxy value of the bisphenol A diglycidyl ether is 0.48-0.54 mol / 100g, and the viscosity at 25°C is 4000-6000 mPa·s.

[0010] Preferably, the ultrafine cement is P.O42.5 type ultrafine cement, with a specific surface area greater than 1000 m². 2 / kg, with an average particle size of less than 8 μm; the fineness of the nano-titanium dioxide is 20-40 nm.

[0011] Preferably, the degree of polymerization of the polyvinyl alcohol is 2000-2200 and the degree of hydrolysis is 88%; the fineness of the hindered amine stabilizer is 300-500 nm, and the hindered amine stabilizer is light stabilizer 770.

[0012] Preferably, a method for preparing the asphalt aging repair agent includes the following steps: Step 1: Add waste cooking oil and waste rubber powder to the reactor, heat to 140-160℃, and stir for 25-35 minutes to allow the waste rubber powder to fully swell, and obtain material 1 for later use; Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 140-160℃ and shear for 55-65 min to form a polyurethane-epoxy composite crosslinked network. The heating rate is 5-6℃ and the shearing speed is 1000-1200 r / min. After cooling, add nano titanium dioxide, polyvinyl alcohol and sulfolane, heat to 120-130℃ and stir for 40-50 min to achieve a uniform organic-inorganic phase composite as material two for later use. Step 3: Place material 1 and material 2 into a reaction vessel and stir slowly at 200-400 r / min until material 1 and material 2 are fully mixed. Then add ultrafine cement, hindered amine stabilizer and water, heat to 50-60℃, and stir until the ultrafine cement and hindered amine stabilizer are dissolved and dispersed. Then stir rapidly at 600-1000 r / min until a stable solution is formed. Finally, filter with a 100-mesh filter to remove impurities and age at 40-50℃ for 20-24 hours to obtain asphalt aging repair agent.

[0013] Preferably, a method for using an asphalt aging repair agent involves heating the asphalt aging repair agent to 40-50°C, placing it in a spraying device, and spraying it in situ onto the aged asphalt to be repaired. The spraying rate is 0.3-0.7 kg / m³. 2 At 50°C, the Engla viscosity is 35-45 Engla degrees.

[0014] Compared with the prior art, the advantages of this application are: (1) This application uses waste cooking oil as the core recycled oil component. Its acid value is ≤5 mg KOH / g and it has been dehydrated and impurity removed. It can efficiently replenish the aromatic and saturated components lost in the aged asphalt, significantly reduce the relative content of asphaltenes, and drive the colloidal structure to reverse from gel type to sol-gel type from the chemical composition level, laying the material basis for the significant recovery of penetration and ductility. In addition, the introduction of waste cooking oil as the core recycled oil component also has significant waste resource utilization benefits. (2) The waste rubber powder used in this application is subjected to microwave desulfurization treatment at a specific frequency (910-920 MHz). The surface active sulfur-containing bonds are broken, releasing highly active polymer segments. During the high-temperature preparation of the repair agent and the road penetration process, these segments physically entangle with asphalt molecules and participate in the chemical grafting reaction initiated by hexamethylene diisocyanate, forming flexible hinges dispersed in the continuous phase of asphalt. This increases the low-temperature ductility of the repaired road surface at 5℃ by 4-9 cm compared with commercially available products, and the low-temperature crack resistance is substantially improved. (3) This application uses hexamethylene diisocyanate as the main crosslinking agent. Its -NCO group content is as high as 48-50%, which can undergo in-situ polymerization reaction with active hydrogen (such as hydroxyl and amino groups) in asphalt and hydroxyl groups of polyvinyl alcohol to generate urethane bonds and urea bonds, and reconstruct a three-dimensional chemical crosslinking skeleton in the loose network of aged asphalt. Bisphenol A diglycidyl ether, with its low viscosity characteristics, not only helps to carry the repair components to penetrate into the depth of microcracks, but also builds molecular bridges between aged asphalt molecules, active segments of waste rubber powder and aggregate surface through the ring-opening reaction of epoxy groups, and forms a rubber-polyurethane-epoxy interpenetrating crosslinking network (IPN) together with the hexamethylene diisocyanate system. (4) The four components in this application, namely waste cooking oil, waste rubber powder, hexamethylene diisocyanate and bisphenol A diglycidyl ether, have a synergistic mechanism. Waste cooking oil replenishes light components and dissolves asphalt, waste rubber powder provides elastic nodes, and hexamethylene diisocyanate and bisphenol A diglycidyl ether simultaneously construct a three-dimensional chemical cross-linking network. The three components complement each other, so that the penetration of the repaired asphalt is restored to the level of new asphalt, while the change in softening point is still controlled in a low range, thus achieving the simultaneous restoration of low-temperature flexibility and high-temperature stability. (5) The present application forms a cross-linked network structure with hexamethylene diisocyanate and bisphenol A diglycidyl ether, and forms a synergistic anti-aging system with hindered amine stabilizer and nano titanium dioxide, which effectively inhibits the secondary aging of the repair agent under the action of heat and oxygen, and the material itself has good thermal stability. (6) The asphalt aging repair agent of this application has low viscosity and good stability. It has excellent adhesion, wear resistance, penetration and waterproof performance, good compatibility and is suitable for high-level complex service environment. When used, it is sprayed on-site without milling the asphalt, so as to achieve the purpose of quickly repairing aged asphalt under low temperature conditions on-site. It is convenient, quick and easy to construct. The preparation process is simple, the equipment requirements are low and the economy is good. Detailed Implementation

[0015] The present application is described in detail below with reference to specific embodiments, but the present application is not limited to these embodiments. The present application covers any alternatives, modifications, equivalent methods, and solutions made within the spirit and scope of the present application. To provide the public with a thorough understanding of the present application, specific details are described in detail in the following embodiments, but those skilled in the art will fully understand the present application even without these detailed descriptions.

[0016] This application provides an asphalt aging repair agent, which is composed of the following components in parts by weight: 25-35 parts waste cooking oil, 21-23 parts waste rubber powder, 8-11 parts hexamethylene diisocyanate, 3-5 parts bisphenol A diglycidyl ether, 3-5 parts polyvinyl alcohol, 5-9 parts sulfolane, 5-8 parts ultrafine cement, 2-3 parts hindered amine stabilizer, 2-3 parts nano titanium dioxide, and 5-10 parts water.

[0017] Preferably, it consists of the following components in parts by mass: 35 parts waste cooking oil, 23 parts waste rubber powder, 11 parts hexamethylene diisocyanate, 5 parts bisphenol A diglycidyl ether, 5 parts polyvinyl alcohol, 9 parts sulfolane, 8 parts ultrafine cement, 3 parts hindered amine stabilizer, 3 parts nano titanium dioxide, and 9 parts water.

[0018] Preferably, the waste cooking oil has an acid value ≤5 mg KOH / g, a moisture content ≤0.1%, and after dehydration and impurity removal, the saturated fatty acid content is 20-40 wt% and the unsaturated fatty acid content is 60-80 wt%.

[0019] Preferably, the waste rubber powder has a particle size of 0.10-0.15 mm and has undergone microwave desulfurization treatment at a frequency of 910-920 MHz for 4-6 min.

[0020] Preferably, the content of isocyanate groups in the hexamethylene diisocyanate is 48-50%, the epoxy value of the bisphenol A diglycidyl ether is 0.48-0.54 mol / 100g, and the viscosity at 25°C is 4000-6000 mPa·s.

[0021] Preferably, the ultrafine cement is P.O42.5 type ultrafine cement, with a specific surface area greater than 1000 m². 2 / kg, with an average particle size of less than 8 μm; the fineness of the nano-titanium dioxide is 20-40 nm.

[0022] Preferably, the degree of polymerization of the polyvinyl alcohol is 2000-2200 and the degree of hydrolysis is 88%; the fineness of the hindered amine stabilizer is 300-500 nm, and the hindered amine stabilizer is light stabilizer 770.

[0023] Preferably, a method for preparing the asphalt aging repair agent includes the following steps: Step 1: Add waste cooking oil and waste rubber powder to the reactor, heat to 140-160℃, and stir for 25-35 minutes to allow the waste rubber powder to fully swell, and obtain material 1 for later use; Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 140-160℃ and shear for 55-65 min to form a polyurethane-epoxy composite crosslinked network. The heating rate is 5-6℃ and the shearing speed is 1000-1200 r / min. After cooling, add nano titanium dioxide, polyvinyl alcohol and sulfolane, heat to 120-130℃ and stir for 40-50 min to achieve a uniform organic-inorganic phase composite as material two for later use. Step 3: Place material 1 and material 2 into a reaction vessel and stir slowly at 200-400 r / min until material 1 and material 2 are fully mixed. Then add ultrafine cement, hindered amine stabilizer and water, heat to 50-60℃, and stir until the ultrafine cement and hindered amine stabilizer are dissolved and dispersed. Then stir rapidly at 600-1000 r / min until a stable solution is formed. Finally, filter with a 100-mesh filter to remove impurities and age at 40-50℃ for 20-24 hours to obtain asphalt aging repair agent.

[0024] Preferably, this application provides a method for using an asphalt aging repair agent. The method involves heating the asphalt aging repair agent to 40-50°C, placing it in a spraying device, and spraying it in situ onto the aged asphalt to be repaired. The spraying rate is 0.3-0.7 kg / m³. 2 At 50°C, the Engla viscosity is 35-45 Engla degrees.

[0025] The asphalt aging repair agent described in this application is a high-penetration in-situ repair agent, comprising base oil, modifier, main crosslinking agent, synergistic crosslinking agent, surfactant, binder, heat-oxidizing agent, and UV-resistant agent. Waste edible oil, as the base oil, replenishes the lightweight components in the asphalt, diluting and dissolving the asphaltenes and reducing viscosity. The addition of waste rubber powder primarily acts as a modifier, enhancing the asphalt's structure. The waste rubber powder swells and partially degrades at high temperatures, releasing active polymer segments that can interact with the asphaltenes in the asphalt. Biophysical entanglement or chemical crosslinking enhances the system's elastic recovery and fatigue resistance. By using hexamethylene diisocyanate (HDI) as the primary crosslinking agent, its -NCO groups can undergo addition reactions with the hydroxyl and amino groups in asphalt and the hydroxyl groups in polyvinyl alcohol, generating stable urea bonds or carbamate bonds to construct a three-dimensional crosslinked network. This in-situ polymerization process not only strengthens the adhesion within the asphalt but also improves the overall thermal stability and water resistance of the material, significantly enhancing its anti-aging and anti-peeling properties. Bisphenol A diglycidyl ether is used as a synergistic crosslinking agent. This agent, with its low viscosity, helps the repair agent penetrate into the micro-pores of the road surface and the surface of the structural asphalt. Simultaneously, through the chemical reaction of epoxy groups, it builds molecular bridges between aged asphalt molecules, the organic network of the repair agent, and the aggregate surface, achieving chemical bonding and interfacial strengthening. Using polyvinyl alcohol as a surfactant reduces the surface energy of aged asphalt, increases the penetration rate, and improves the dispersion of each component. Using ultrafine cement as a binder, its hydration products gradually form a film with the demulsified asphalt particles, interweaving to form an interpenetrating network structure, thus strengthening and repairing cracks. Using sulfolane as a dispersant dissolves hindered amine stabilizers and some asphaltene, while efficiently dispersing titanium dioxide, exhibiting good thermal stability. The use of hindered amine stabilizers resists thermal, oxygen, and ultraviolet aging, inhibits chain initiation and growth reactions, and is self-recyclable, maintaining long-term anti-aging effects. The use of nano-titanium dioxide resists ultraviolet aging, absorbing, reflecting, and scattering most ultraviolet light, and also absorbs vehicle exhaust, making it environmentally friendly.

[0026] This application discloses an asphalt aging repair agent that incorporates a low-viscosity component composed of waste cooking oil, a crosslinking agent, and a surfactant. This component works synergistically to enhance the penetration and diffusion capacity of the repair agent. It eliminates the need for milling and allows for on-site spraying, achieving rapid repair of aged asphalt under low-temperature conditions. This method is convenient, quick, and easy to apply. Furthermore, by adding different components to address different causes of aging, it comprehensively improves the asphalt's resistance to light, oxygen, and heat aging, resulting in a holistic improvement effect. In addition, the use of waste cooking oil and waste rubber powder helps promote the resource utilization of waste materials.

[0027] Example 1 This embodiment discloses an asphalt aging repair agent, which, by mass parts, includes 25 parts waste cooking oil, 21 parts waste rubber powder, 8 parts hexamethylene diisocyanate, 3 parts bisphenol A diglycidyl ether, 3 parts polyvinyl alcohol, 5 parts sulfolane, 5 parts ultrafine cement, 2 parts hindered amine stabilizer, 2 parts nano titanium dioxide, and 5 parts water.

[0028] The waste edible oil had an acid value of 5 mg KOH / g and underwent dehydration and impurity removal treatment; the waste rubber powder had a particle size of 0.12 mm and underwent microwave desulfurization treatment at a frequency of 910 MHz for 6 min; the hexamethylene diisocyanate had an -NCO content of 48%; the bisphenol A diglycidyl ether had an epoxy value of 0.48 mol / 100g; and the ultrafine cement used was P.O42.5 type ultrafine cement with a specific surface area of ​​1000 m². 2 / kg, with an average particle size of 7.8 μm; the hindered amine stabilizer has a fineness of 300 nm, and the hindered amine stabilizer used is light stabilizer 770; the nano titanium dioxide has a fineness of 20 nm, and tap water is used.

[0029] The preparation method of the asphalt aging repair agent described in Example 1 includes the following steps: Step 1: Add waste rubber powder and waste cooking oil to the reactor, heat to 150°C at a rate of 5°C, stir for 30 minutes to allow the rubber powder to fully swell, and obtain material 1 for later use. Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 150°C at a heating rate of 5°C and shear at high speed for 60 min to form a polyurethane-epoxy composite crosslinked network. The high-speed shearing speed is 1100 r / min. After cooling, add nano titanium dioxide dispersion, polyvinyl alcohol solution and sulfolane. Heat to 125°C at a heating rate of 5°C and stir for 45 min to achieve uniform organic-inorganic phase composite. The stirring rate is 300 r / min. This is used as material two for later use. Step 3: Place material 1 and material 2 into a reaction vessel and stir slowly until material 1 and material 2 are fully mixed; then add ultrafine cement, hindered amine stabilizer and water, and heat to 55°C; stir slowly until the ultrafine cement and hindered amine stabilizer dissolve, with a stirring speed of 300 r / min, and then stir rapidly until a stable solution is formed; finally, filter with a 100-mesh filter to remove impurities, and age at 45°C for 24 h to obtain the asphalt aging repair agent. The obtained asphalt aging repair agent is kept warm at a low temperature of 20°C.

[0030] Example 2 An asphalt aging repair agent, by weight, comprises 30 parts waste cooking oil, 22 parts waste rubber powder, 10 parts hexamethylene diisocyanate, 4 parts bisphenol A diglycidyl ether, 4 parts polyvinyl alcohol, 8 parts sulfolane, 7 parts ultrafine cement, 2.5 parts hindered amine stabilizer, 2.5 parts nano titanium dioxide, and 8 parts water.

[0031] The waste edible oil had an acid value of 4.5 mg KOH / g and underwent dehydration and impurity removal treatment; the waste rubber powder had a particle size of 0.13 mm and underwent microwave desulfurization treatment at a frequency of 915 MHz for 5 min; hexamethylene diisocyanate had an -NCO content of 49%; bisphenol A diglycidyl ether had an epoxy value of 0.49 mol / 100g; and the ultrafine cement used was P.O42.5 type ultrafine cement with a specific surface area of ​​1100 m². 2 / kg, with an average particle size of 7.9 μm; the hindered amine stabilizer has a fineness of 400 nm, and the hindered amine stabilizer used is light stabilizer 770; the nano titanium dioxide has a fineness of 20 nm, and tap water is used.

[0032] The preparation method of the asphalt aging repair agent described in Example 2 includes the following steps: Step 1: Add waste rubber powder and waste cooking oil to the reactor, heat to 155°C at a heating rate of 5.5°C, stir for 32 minutes to allow the rubber powder to fully swell, and obtain material 1 for later use. Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 155°C at a heating rate of 5.5°C and shear at high speed for 62 min to form a polyurethane-epoxy composite crosslinked network. The high-speed shearing speed is 1150 r / min. After cooling, add nano titanium dioxide dispersion, polyvinyl alcohol solution and sulfolane. Heat to 120°C at a heating rate of 5.5°C and stir for 50 min to achieve uniform organic-inorganic phase composite. The stirring speed is 300 r / min. This is used as material two for later use. Step 3: Place material 1 and material 2 into a reaction vessel and stir slowly until material 1 and material 2 are fully mixed; then add ultrafine cement, hindered amine stabilizer and water, and heat to 58°C; stir slowly until the ultrafine cement and hindered amine stabilizer dissolve, with a stirring speed of 300 r / min, and then stir rapidly until a stable solution is formed; finally, filter with a 100-mesh filter to remove impurities and age at 45°C for 24 h to obtain the asphalt aging repair agent. The obtained asphalt aging repair agent is kept at a low temperature of 18°C.

[0033] Example 3 An asphalt aging repair agent, by weight, comprises 35 parts waste cooking oil, 23 parts waste rubber powder, 11 parts hexamethylene diisocyanate, 5 parts bisphenol A diglycidyl ether, 5 parts polyvinyl alcohol, 9 parts sulfolane, 8 parts ultrafine cement, 3 parts hindered amine stabilizer, 3 parts nano titanium dioxide, and 9 parts water.

[0034] The waste edible oil had an acid value of 4.3 mg KOH / g and underwent dehydration and impurity removal treatment; the waste rubber powder had a particle size of 0.15 mm and underwent microwave desulfurization treatment at a frequency of 920 MHz for 4 min; the hexamethylene diisocyanate had an -NCO content of 48%; the bisphenol A diglycidyl ether had an epoxy value of 0.54 mol / 100g; and the ultrafine cement used was P.O42.5 type ultrafine cement with a specific surface area of ​​1200 m². 2 / kg, with an average particle size of 7.7 μm; the hindered amine stabilizer has a fineness of 500 nm, and the hindered amine stabilizer used is light stabilizer 770; the nano titanium dioxide has a fineness of 20 nm, and tap water is used.

[0035] The preparation method of the asphalt aging repair agent described in Example 3 includes the following steps: Step 1: Add waste rubber powder and waste cooking oil to the reactor, heat to 160°C at a heating rate of 6°C, stir for 40 minutes to allow the rubber powder to fully swell, and obtain material 1 for later use. Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 160°C at a heating rate of 6°C and shear at high speed for 65 min to form a polyurethane-epoxy composite crosslinked network. The high-speed shearing speed is 1200 r / min. After cooling, add nano titanium dioxide dispersion, polyvinyl alcohol solution and sulfolane, heat to 130°C at a heating rate of 6°C and stir for 40 min to achieve uniform organic-inorganic phase composite. The stirring speed is 300 r / min. This is used as material two for later use. Step 3: Place the above materials 1 and 2 into a reaction vessel and stir slowly until materials 1 and 2 are fully mixed; then add ultrafine cement, hindered amine stabilizer and water, and heat to 60°C; stir slowly until the ultrafine cement and hindered amine stabilizer dissolve, with a stirring speed of 300 r / min, and then stir rapidly until a stable solution is formed; finally, filter with a 100-mesh filter to remove impurities and age at 45°C for 24 h to obtain the asphalt aging repair agent. The obtained asphalt aging repair agent is kept at a low temperature of 15°C.

[0036] The following compares the various indicators of the three asphalt aging repair agents obtained in Examples 1-3 with a commercially available asphalt pavement fog seal repair agent. The results are shown in Table 1 below.

[0037] Short-term aging tests were conducted in a rotating thin-film oven (RTFOT) according to the provisions of the transportation industry standard JTG 3410-2025 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". After aging, the mixture was cooled to room temperature, and the above four materials were sprayed onto the surface of the test matrix asphalt (Karamay grade 70#) at a weight percentage of 1%, with a thickness of 0.3-0.5 mm. To characterize their high penetration ability, penetration, softening point, and ductility were used as evaluation indicators. The test results are shown in Table 2.

[0038] Table 1 Performance Tests of Asphalt Aging Rapid Repair Agent As shown in Table 1, the viscosity of the repair agent at 60℃ is in the range of 93-117 Pa·s, which is lower than the 132 Pa·s of commercially available fog seal materials. The penetration depth reaches 15.2-17.4 mm, significantly greater than the 12.3 mm of commercially available materials. This indicates that the compounding of waste edible oil and sulfolane effectively reduces the system viscosity and enhances the penetration and diffusion ability of the repair agent into the aged asphalt. Meanwhile, the residual penetration ratio after 60 hours of aging in the film oven is 90.3%-93.1%, and the mass loss rate is 0.29-0.42, both meeting the specifications and superior to commercially available materials. This demonstrates that the cross-linked network structure formed by hexamethylene diisocyanate and bisphenol A diglycidyl ether, as well as the synergistic anti-aging system of hindered amine stabilizer and nano-titanium dioxide, effectively inhibits the secondary aging of the repair agent under thermo-oxidative conditions, and the material itself exhibits good thermal stability.

[0039] As shown in Table 1, the material of this application has low viscosity, minimal viscosity and mass loss before and after aging, and good stability. Its adhesion, wear resistance, permeability, and waterproofing performance are excellent, and all properties meet the requirements of the "Technical Specification for Preventive Maintenance of Highway Asphalt Pavement" (JTG / T5142-01-2021) for highway asphalt pavement fog seal materials. Its low viscosity and high permeability characteristics improve construction efficiency and allow for deep repair of aged asphalt; its superior impermeability and stability effectively extend its service life. This material is a comprehensive asphalt aging repair material.

[0040] Table 2. Performance of asphalt before and after aging using different asphalt aging repair agents As shown in Table 2, the test results indicate that spraying asphalt aging repair agent significantly improves the aging of asphalt after it has been aged in a rotating thin-film oven. Specifically, this is manifested in a decrease in asphalt penetration, an increase in softening point, and a reduction in ductility. Compared to commercially available repair agents, the material presented in this application is more effective in mitigating the consistency hardening problem after asphalt aging. The penetration at 25°C shows that the penetration recovery rate of the asphalt treated in Examples 1-3 is higher than that of commercially available repair agents. Regarding the softening point, the softening point of the asphalt repaired with commercially available repair agents changes more significantly than that of the material presented in this application. The material presented in this application, through cross-linking network reconstruction, achieves a gentle decrease in softening point and maintains a low rate of change, thus restoring flexibility while ensuring high-temperature stability. In summary, compared to commercially available fog repair agents, the material presented in this application can more comprehensively improve the performance of asphalt after aging, and is more conducive to maintaining the core road performance characteristics such as crack resistance and deformation resistance of the pavement over the long term.

[0041] As shown in Table 2, after spraying the repair agent of this application, the penetration and ductility of the aged asphalt gradually recovered over time, while the softening point remained within a reasonable range. For example, in Example 3, the penetration recovery rate reached 96.0% at 25℃ after repair, and the ductility recovered to 21.4 cm at 5℃. The significant recovery of penetration was attributed to the effective replenishment of lightweight components by waste edible oil and the swelling and dispersion of asphaltene by sulfolane. The significant improvement in ductility was attributed to the rubber-polyurethane-epoxy interpenetrating crosslinking network formed by the active segments released from microwave desulfurized waste rubber powder, hexamethylene diisocyanate, and bisphenol A diglycidyl ether. This network absorbs stress and delays crack propagation during low-temperature tensile testing through the synergistic effect of flexible segment movement and chemical crosslinking points. Simultaneously, the change in softening point was only +2.5, indicating that the crosslinking network provided sufficient skeletal rigidity, ensuring that the repaired asphalt regained its flexibility without experiencing high-temperature performance degradation.

[0042] To study its actual effect, three Class I pavements with ages of 1 year, 2 years, and 4 years, with a total length of 0.6 km, were selected as the research objects. The surface layer used SMA-13 ​​asphalt mixture, and the middle and lower layers used AC-13 asphalt mixture. Core samples (12.5 mm deep, 12.5 mm in diameter) were taken every 0.2 km, with 3 samples taken each time (random sampling). The degree of asphalt aging was tested using a portable diffuse reflectance infrared spectroscopy (DRIFTS), and the approximate content of functional groups in the asphalt was determined, including saturated components (CH, (alCH2)). a The composition of the asphalt pavement is determined by the presence of asphalt (alCH3), aromatic hydrocarbons (arC=C and arCH), resins, and macromolecular asphaltenes. The content of each component before and after the application of the repair agent is shown in Table 3 below. The component data in the table are the arithmetic mean of the test results from three parallel core samples taken at each pile number.

[0043] Table 3. Content of various components in asphalt pavement before application of repair agent. As shown in Table 3, after applying the repair agent of this application for 3 hours on road sections with different aging levels, all four components of asphalt showed a trend of increasing light components (saturated and aromatic components) and decreasing heavy components (asphaltite). Specifically, in the 1-year-old road section, the saturated component increased by approximately 3.6%, and the aromatic component recovered to approximately 49.2%, approaching the level of new asphalt; the asphaltite decreased by approximately 4.6%, indicating that the light components were effectively replenished while the heavy components relatively decreased. In the 2-year-old road section, the saturated component increased to 19.1%, the aromatic component rose to 46.8%, and the asphaltite decreased to 9.6%, with the proportion of resin declining and the component structure shifting towards an equilibrium state. Although the 4-year-old road section was more severely aged, the saturated component still increased by 2.7%, the aromatic component increased from 33.5% to 39.1%, and the relative content of asphaltite decreased by approximately 4.6 percentage points, with a significant rebound in light components and partial dissolution and dispersion of asphaltite aggregates. The aforementioned component changes confirm that the repair agent of this application can quickly penetrate aged asphalt, replenish light oils and dissolve and disperse asphalt aggregates through the synergistic effect of waste edible oil and sulfolane, thereby achieving in-situ regeneration and repair of the asphalt colloidal structure.

[0044] The asphalt aging repair agent described in this application exhibits significant synergistic effects among its components. Specifically, waste edible oil (a supplement to the light components) and sulfolane (an asphalt solvent) work synergistically to drive the reversal of the colloidal structure from a gel type to a sol type. Waste rubber powder swells and absorbs some of the light components, forming elastic nodes. The hexamethylene diisocyanate / bisphenol A diglycidyl ether crosslinking network simultaneously forms a spatial framework during component exchange, ensuring that the pavement strength is not lost after component migration.

[0045] From the perspective of mechanism of action, the -NCO groups of hexamethylene diisocyanate react with the hydroxyl groups of asphalt and polyvinyl alcohol to construct a three-dimensional cross-linked network. Bisphenol A diglycidyl ether, with its low viscosity, assists in penetration and builds interfacial molecular bridges. Ultrafine cement hydration products interweave with the organic network to fill microcracks. In terms of anti-aging, hindered amine stabilizers achieve recycling by chemically capturing free radicals, while nano-titanium dioxide reduces the number of photo-initiated free radicals by physically shielding ultraviolet rays. The two work synergistically to extend the service life of the material.

[0046] Based on the above experimental data and mechanism analysis, the repair agent of this application is suitable for in-situ regeneration and repair of aging defects in asphalt pavement of high-grade highways, and can achieve simultaneous improvement in pavement mechanical properties and durability.

[0047] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

[0048] Many other changes and modifications can be made without departing from the concept and scope of this application. It should be understood that this application is not limited to the specific embodiments, and the scope of this application is defined by the appended claims.

Claims

1. An asphalt aging repair agent, characterized in that, It consists of the following components in parts by mass: 25-35 parts waste cooking oil, 21-23 parts waste rubber powder, 8-11 parts hexamethylene diisocyanate, 3-5 parts bisphenol A diglycidyl ether, 3-5 parts polyvinyl alcohol, 5-9 parts sulfolane, 5-8 parts ultrafine cement, 2-3 parts hindered amine stabilizer, 2-3 parts nano titanium dioxide, and 5-10 parts water.

2. The asphalt aging repair agent according to claim 1, characterized in that, It consists of the following components in parts by mass: 35 parts waste cooking oil, 23 parts waste rubber powder, 11 parts hexamethylene diisocyanate, 5 parts bisphenol A diglycidyl ether, 5 parts polyvinyl alcohol, 9 parts sulfolane, 8 parts ultrafine cement, 3 parts hindered amine stabilizer, 3 parts nano titanium dioxide, and 9 parts water.

3. The asphalt aging repair agent according to claim 1, characterized in that: The waste cooking oil has an acid value ≤5 mg KOH / g and a moisture content ≤0.1%. After dehydration and impurity removal, the waste cooking oil has a saturated fatty acid content of 20-40 wt% and an unsaturated fatty acid content of 60-80 wt%.

4. The asphalt aging repair agent according to claim 1, characterized in that: The waste rubber powder has a particle size of 0.10-0.15 mm and has undergone microwave desulfurization treatment at a frequency of 910-920 MHz for 4-6 min.

5. The asphalt aging repair agent according to claim 1, characterized in that, The isocyanate group content of the hexamethylene diisocyanate is 48-50%, the epoxy value of the bisphenol A diglycidyl ether is 0.48-0.54 mol / 100g, and the viscosity at 25℃ is 4000-6000 mPa·s.

6. The asphalt aging repair agent according to claim 1, characterized in that: The ultrafine cement used is P.O42.5 type ultrafine cement, with a specific surface area greater than 1000 m². 2 / kg, with an average particle size of less than 8 μm; the fineness of the nano-titanium dioxide is 20-40 nm.

7. The asphalt aging repair agent according to claim 1, characterized in that: The degree of polymerization of the polyvinyl alcohol is 2000-2200, and the degree of hydrolysis is 88%; the fineness of the hindered amine stabilizer is 300-500 nm, and the hindered amine stabilizer used is light stabilizer 770.

8. A method for preparing the asphalt aging repair agent according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Add waste cooking oil and waste rubber powder to the reactor, heat to 140-160℃, and stir for 25-35 minutes to allow the waste rubber powder to fully swell, and obtain material 1 for later use; Step 2: Add bisphenol A diglycidyl ether to hexamethylene diisocyanate, heat to 140-160℃ and shear for 55-65 min to form a polyurethane-epoxy composite crosslinked network. The heating rate is 5-6℃ and the shearing speed is 1000-1200 r / min. After cooling, add nano titanium dioxide, polyvinyl alcohol and sulfolane, heat to 120-130℃ and stir for 40-50 min to achieve a uniform organic-inorganic phase composite as material two for later use. Step 3: Place material 1 and material 2 into a reaction vessel and stir slowly at 200-400 r / min until material 1 and material 2 are fully mixed. Then add ultrafine cement, hindered amine stabilizer and water, heat to 50-60℃, and stir until the ultrafine cement and hindered amine stabilizer are dissolved and dispersed. Then stir rapidly at 600-1000 r / min until a stable solution is formed. Finally, filter with a 100-mesh filter to remove impurities and age at 40-50℃ for 20-24 hours to obtain asphalt aging repair agent.

9. A method for using an asphalt aging repair agent, characterized in that, The method of using the asphalt aging repair agent according to any one of claims 1-7 is as follows: after heating the asphalt aging repair agent to 40-50℃, place it in a spraying device and spray it in situ onto the aged asphalt to be repaired, with a spraying rate of 0.3-0.7 kg / m³. 2 At 50°C, the Engra viscosity is 35-45 Engra degrees.

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