Microwave sensitive asphalt regenerant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to a microwave sensitive asphalt regenerant and a preparation method and application thereof.The microwave sensitive asphalt regenerant is prepared from, by mass, 70-90 parts of vegetable oil, 5-25 parts of SBS, 0-4 parts of DBP and 1-5 parts of modified carbon powder, and the modified carbon powder is carbon powder modified through a silane coupling agent. According to the microwave-sensitive asphalt regenerant, effective balance of microwave sensitivity and regenerated asphalt stability of the regenerant is achieved through effective cooperation of the vegetable oil, the SBS, the DBP and the modified carbon powder, meanwhile, the adopted raw materials are bulk chemical raw materials, the raw materials are wide in source and low in cost, economical efficiency and environment friendliness of large-scale application are achieved, and the microwave-sensitive asphalt regenerant is suitable for industrial production. The problem that an asphalt regenerant in the prior art is difficult to consider microwave absorptivity, regeneration stability and economic and environment-friendly properties at the same time is solved.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, specifically to a microwave-sensitive asphalt rejuvenator, its preparation method, and its application, and more particularly to a microwave-sensitive rejuvenator for asphalt pavement regeneration, its preparation method, and its application. Background Technology

[0002] With the continuous advancement of transportation infrastructure construction and the ongoing improvement of highway networks, asphalt pavement, as the most commonly used pavement type in highway construction, inevitably suffers from the repeated effects of vehicle loads, erosion from natural environmental factors, and ultraviolet radiation during long-term use. This leads to the gradual deterioration of pavement performance, resulting in defects such as cracks, ruts, and potholes, seriously affecting driving safety and comfort. The traditional approach is to discard the old asphalt pavement material directly and repave it with new asphalt mixture. However, this practice not only wastes a large amount of recyclable resources but also generates a large amount of construction waste, causing serious environmental pollution.

[0003] Against this backdrop, asphalt pavement recycling technology has emerged. By recycling old asphalt pavement materials, asphalt pavement recycling technology can significantly reduce resource consumption and environmental pollution. Among them, microwave heating recycling technology has become a research hotspot due to its advantages such as fast heating speed and small impact on surrounding structures. As the core material of this process, the performance of the recycling agent directly determines the recycling effect of old asphalt mixture. However, existing asphalt recycling agents still have the following key technical defects when adapted to microwave heating recycling scenarios: Traditional asphalt recycling agents are mostly composed of petroleum distillate oil, coal tar, etc., and their design goals focus on improving the viscosity and ductility of aged asphalt, lacking targeted design for microwave energy absorption characteristics. Specifically, (1) The main components of traditional recycling agents are non-polar organic compounds with weak molecular polarity and lack of microwave-sensitive groups (such as conjugated structures, magnetic particles, etc.), resulting in a small absorption cross section and low conversion efficiency for microwave energy. (2) During microwave heating, the regenerator relies on the aggregates (such as quartz and limestone) in the old asphalt for indirect heat absorption, which easily leads to the phenomenon of "heating lag" - that is, the aggregate heats up quickly while the interface between the regenerator and the old asphalt heats up slowly, resulting in uneven heating (the local temperature difference can reach more than 20°C), which prolongs the construction time (30%~50% longer than the ideal state), and is prone to causing secondary aging of asphalt due to local overheating. (3) The compatibility design between traditional regenerators and aged asphalt is insufficient. Its components are mostly low molecular weight alkanes or aromatics. Although they can reduce the viscosity of aged asphalt, they are difficult to repair the damaged asphalt colloidal structure (such as the dispersion stability of asphalt aggregates) during the aging process. In practical applications, the regenerated asphalt mixed with traditional regenerators often has the problem of "short-term performance meeting the standard, but long-term performance decaying quickly". Specifically, the ductility increase at 5°C is less than 20cm (the ductility of aged asphalt is usually <5cm), and the dynamic stability decreases by <30%, which cannot meet the long-term use requirements of heavy traffic pavement.

[0004] In existing technologies, to improve the microwave sensitivity of regenerants, microwave absorbing materials are typically introduced, mainly including metal powders, magnetic materials, and some carbon-based materials. Among these, the introduction of metal powders, such as aluminum powder and iron powder, while possessing high microwave reflection and eddy current loss capabilities (microwave absorption efficiency can reach 60%-70%), has a high density (>2.7 g / cm³). 3The introduction of metal powders can lead to poor compatibility with asphalt, causing sedimentation and stratification during storage and construction, resulting in decreased material uniformity. Furthermore, the introduction of metal powders may increase the conductivity of asphalt mixtures, interfering with the electromagnetic environment of construction equipment. The introduction of magnetic materials such as ferrites and neodymium iron boron particles absorbs microwaves through hysteresis loss, but their raw material costs are high, and the low surface activity of the magnetic particles results in weak interfacial bonding with asphalt, making them prone to agglomeration during mixing and affecting the uniform transfer of microwave energy. The introduction of carbon-based materials such as carbon black and graphite powder, while lower in cost and exhibiting good microwave absorption stability, results in a wide particle size distribution (typically >50μm) and fewer surface functional groups, leading to insufficient compatibility with asphalt and the formation of localized high-concentration areas. This can cause a decrease in the low-temperature crack resistance of recycled asphalt (a 10%-15% reduction in ductility at 5℃).

[0005] In summary, existing asphalt recycling agents, when used in microwave heating recycling scenarios, either suffer from low heating efficiency due to a lack of microwave-sensitive design, or the introduced microwave-sensitive materials suffer from high costs, poor compatibility, and insufficient environmental friendliness. These limitations make it difficult to simultaneously meet the comprehensive requirements of microwave absorption efficiency, recycling performance, economic efficiency, and environmental friendliness. Therefore, developing a novel recycling agent based on low-cost, highly compatible raw materials, while possessing excellent microwave sensitivity and recycling performance, is crucial for promoting the large-scale application of microwave heating recycling technology. Summary of the Invention

[0006] To address the problem that existing asphalt recycling agents cannot simultaneously achieve microwave absorption rate, recycling stability, and economic and environmental benefits, this invention provides a microwave-sensitive asphalt recycling agent, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a microwave-sensitive asphalt rejuvenator, comprising, by weight, 70-90 parts vegetable oil, 5-25 parts styrene-butadiene-styrene block copolymer (SBS), 0-4 parts dibutyl phthalate (DBP), and 1-5 parts modified toner, wherein the modified toner is toner modified with a silane coupling agent.

[0008] Optionally, the vegetable oil has an acid value ≤0.5mgKOH / g, an iodine value of 120-140gI2 / 100g, and an unsaturated fatty acid glyceride content >95%.

[0009] Optionally, the SBS has a molecular weight of 100,000 to 200,000 and a styrene content of 30% to 40%.

[0010] Optionally, the modified toner is toner modified with KH550 silane coupling agent.

[0011] The present invention also provides a method for preparing the microwave-sensitive asphalt rejuvenator as described above, comprising: The vegetable oil and DBP were heated and stirred until they were evenly mixed to obtain the oil phase system. Add SBS to the oil phase system, heat and stir a second time until the SBS is completely swollen to obtain a mixed viscous system; Modified carbon powder is added to the mixed viscous system, and the mixture is cooled and stirred until the carbon powder is evenly dispersed. The mixture is then cooled and molded to obtain a microwave-sensitive asphalt rejuvenator.

[0012] Optionally, it also includes a vegetable oil pretreatment process, specifically: The vegetable oil was dehydrated by rotary evaporation at 90–110℃ and -0.1–-0.08 MPa until the moisture content in the vegetable oil was ≤0.1 wt%, thus completing the vegetable oil pretreatment process.

[0013] Optionally, the modified toner is prepared by: The toner and KH550 silane coupling agent were mixed in an ethanol aqueous solution at a mass ratio of (90-110):2, reacted at 55-75℃ for 1.5-3 hours, and dried to obtain the modified toner.

[0014] Optionally, the temperature for the first stirring and heating is 150–160°C, and the stirring speed is 3000–5000 r / min; the temperature for the second stirring and heating is 175–185°C, and the stirring speed is 3000–5000 r / min; the temperature for the cooling and stirring is 100–110°C, and the stirring speed is 3000–5000 r / min.

[0015] Optionally, the heating rate for the second heating and stirring is 4–6 °C / min.

[0016] The above-mentioned microwave-sensitive asphalt rejuvenator is used in asphalt pavement repair.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a microwave-sensitive asphalt rejuvenator, comprising vegetable oil, SBS, DBP, and modified carbon powder. The main component of the vegetable oil is unsaturated fatty acid glycerides. The ester groups in the molecular structure of the vegetable oil have good affinity with the asphaltenes in aged asphalt, allowing it to penetrate into the colloidal structure of the aged asphalt, diluting the asphaltenes aggregates and improving its low-temperature ductility. As the base component of the rejuvenator, the vegetable oil not only provides the necessary light oil content but also effectively improves the physical properties of the aged asphalt through its chemical structure. SBS, as an elastic reinforcing component, has flexible butadiene segments that enhance the elastic recovery performance of the rejuvenated asphalt, enabling it to quickly return to its original shape after stress and reducing permanent deformation. Its rigid styrene segments enhance high-temperature resistance to deformation, preventing asphalt from flowing or deforming under high-temperature conditions and improving the high-temperature stability of the asphalt. DBP, as a plasticizer, reduces the viscosity of the vegetable oil and SBS mixture, optimizes processing fluidity, and promotes the swelling and dispersion of SBS in the vegetable oil, improving system uniformity and ensuring the stability and consistency of the rejuvenator's performance. The layered structure and conjugated π-electron system of the modified toner can efficiently absorb microwave energy through dielectric loss, endowing the regenerator with microwave sensitivity, thereby enabling rapid heating and softening of the regenerator. This microwave sensitivity allows the regenerator to soften rapidly at lower temperatures, improving regeneration efficiency while reducing energy consumption. Furthermore, the modified toner has better organic phase compatibility, allowing it to better integrate with components such as vegetable oil and SBS, enhancing the overall performance of the regenerator. This microwave-sensitive asphalt regenerator achieves an effective balance between microwave sensitivity and regenerated asphalt stability through the effective synergy of vegetable oil, SBS, DBP, and modified toner. Simultaneously, the raw materials used are all bulk chemical raw materials, with wide availability and low cost, making it economically viable for large-scale application. The use of vegetable oil-based materials instead of traditional petroleum distillate oil reduces the consumption of non-renewable resources. After modification with a silane coupling agent, the heavy metal ion content of the toner is <0.05mg / kg, and the production process emits no toxic gases, making it environmentally friendly.

[0018] This invention also provides a method for preparing the microwave-sensitive asphalt rejuvenator as described above. The method first involves mixing vegetable oil and DBP to form an oil-phase system; then, SBS is added to the oil-phase system to allow the SBS to fully swell and increase the system viscosity; finally, modified carbon powder is added, and the mixture is cooled and molded to obtain the microwave-sensitive asphalt rejuvenator. Testing shows that this method, through component synergistic design and process optimization, significantly outperforms existing technologies in terms of microwave heating performance, rejuvenated asphalt repair effect, economy, and environmental friendliness. Specifically, the performance is as follows: (1) By introducing modified carbon powder, the absorption cross section of the regenerator for microwave energy is significantly increased. Under 2KW microwave power, the heating rate can reach 10-15℃ / min, which is 20-30% higher than that of traditional petroleum-based regenerators (<5℃ / min) and 25-50% higher than that of regenerators with added carbon black. The layered structure of the carbon powder and the compatibility of the modified surface ensure that it is uniformly dispersed in the system, avoiding the sedimentation problem of metal powder (fluorescence microscope rating 1-2, no obvious agglomeration), realizing uniform heating under microwave field (local temperature difference ≤5℃), and shortening the regeneration construction time by more than 30%.

[0019] (2) The unsaturated fatty acids in vegetable oil can penetrate the colloidal structure of aged asphalt and dilute the asphalt aggregates; the elastic network formed by SBS repairs the viscoelastic properties; and DBP optimizes the fluidity during processing. The synergistic effect of these three factors significantly improves the performance of recycled asphalt: the ductility at 5℃ increases from <5cm in aged asphalt to 20-30cm (an increase of 15-25cm), the softening point increases from 45-50℃ to 48-55℃ (an increase of 3-5℃), and the penetration at 25℃ (0.1mm) recovers to 60-80 (20-30 in aged asphalt). In terms of road performance, the complex modulus (G* / sinδ) at 60℃ decreases by 30-40% (improving high-temperature rutting resistance), the stiffness modulus (S) at -12℃ decreases by 20-30%, and the creep rate (m) increases by 15-20% (improving low-temperature crack resistance), meeting the technical requirements for heavy traffic pavements in the "Technical Specification for Recycling Asphalt Pavement of Highways" (JTG / T 5521-2019).

[0020] The aforementioned microwave-sensitive asphalt rejuvenator is applied in asphalt pavement repair. During the asphalt pavement repair process, this microwave-sensitive asphalt rejuvenator can rapidly penetrate into the interior of the asphalt pavement under microwave action, achieving simultaneous internal and external heating, significantly shortening softening time and improving on-site work efficiency. After microwave heating and regeneration, the flexural tensile strength, breaking stiffness modulus, and breaking strain of the asphalt mixture are significantly improved, low-temperature flexibility is enhanced, effectively reducing thermal shrinkage cracks and fatigue cracks, and extending pavement service life. Simultaneously, the SBS component in the rejuvenator enhances the asphalt's high-temperature deformation resistance through rigid chain segments, reducing rutting and other defects, and adapting to heavy traffic demands. Compared to traditional methods, the microwave-sensitive rejuvenator can effectively improve the utilization rate of old materials, reduce the use of new materials, and lower material costs. Through its core advantages such as rapid softening, performance restoration, and economic and environmental friendliness, this microwave-sensitive asphalt rejuvenator solves the problems of low efficiency, high pollution, and high cost in traditional asphalt pavement repair, providing an efficient, green, and sustainable solution for road maintenance. Its application not only improves pavement quality and service life but also promotes technological upgrading in the highway industry, resulting in significant social and economic benefits. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the preparation method of a microwave-sensitive asphalt rejuvenator according to the present invention. Detailed Implementation

[0022] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0023] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0024] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0025] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0026] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0028] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0029] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0030] This invention provides a microwave-sensitive asphalt rejuvenator, comprising, by weight, 70-90 parts vegetable oil, 5-25 parts SBS, 0-4 parts DBP, and 1-5 parts modified carbon powder, wherein the modified carbon powder is carbon powder modified by a silane coupling agent.

[0031] Preferably, the vegetable oil has an acid value ≤0.5mgKOH / g, an iodine value of 120-140gI2 / 100g, and an unsaturated fatty acid glyceride content >95%. The ester groups in the unsaturated fatty acid glycerides have good affinity with the asphaltenes in aged asphalt, allowing them to penetrate the colloidal structure of the aged asphalt, dilute the asphaltenes aggregates, and improve its low-temperature ductility. More preferably, the vegetable oil is soybean oil or rapeseed oil, and the preferred dosage is 80 parts (when the dosage is <70 parts, the improvement in low-temperature ductility is insufficient; when it is >90 parts, it easily leads to low high-temperature viscosity of the recycled asphalt).

[0032] The SBS, as an elastic reinforcing component, has flexible butadiene segments that improve the elastic recovery properties of recycled asphalt, while rigid styrene segments enhance its resistance to high-temperature deformation. Preferably, the molecular weight of the SBS is 100,000 to 200,000, and the styrene content in the SBS is 30% to 40%. More preferably, it is SBS with a linear or star-shaped structure. The weight ratio is further preferably 15 parts (elastic recovery rate <60% when the amount is <5 parts; >25 parts can easily lead to excessively high system viscosity and processing difficulties).

[0033] The DBP used was analytical grade DBP (purity ≥ 99%, density 0.98 g / cm³). 3 As a plasticizer, it can reduce the viscosity of the vegetable oil and SBS mixture system, optimize processing fluidity, and promote the swelling and dispersion of SBS in vegetable oil, thereby improving the uniformity of the system. The optimal ratio is 2 parts (the swelling effect is poor when the amount is <1 part; and it is easy to cause the high-temperature performance degradation of recycled asphalt when the amount is >4 parts).

[0034] The modified carbon powder preferably has a particle size of 10-50 μm and a specific surface area of ​​50-100 m². 2The graphitized carbon powder (carbon content ≥ 99%), with its layered structure and conjugated π-electron system, efficiently absorbs microwave energy through dielectric loss, endowing the regenerator with microwave sensitivity. To improve compatibility with the organic phase, the carbon powder needs to be modified with KH550 silane coupling agent. The preferred weight ratio is 3 parts (when the amount is < 1 part, the microwave heating rate is < 8℃ / min; when > 5 parts, it is prone to agglomeration, leading to decreased compatibility).

[0035] The optimized formulation of this invention is further highlighted in the table below:

[0036] See Figure 1 The present invention provides a method for preparing the microwave-sensitive asphalt rejuvenator as described above, comprising: S1: Mix vegetable oil and DBP, heat and stir until homogeneous to obtain the oil phase system, specifically: The vegetable oil was dehydrated by rotary evaporation at 90–110℃ and -0.1–-0.08 MPa until the moisture content in the vegetable oil was ≤0.1 wt%, thus completing the vegetable oil pretreatment process. The pretreated vegetable oil and DBP were added to a reaction vessel equipped with a stirrer. The mixture was heated to 150-160°C while stirring at 3000-5000 r / min and reacted for 1-1.5 h to form a homogeneous oil phase system (viscosity ≤500 mPa·s).

[0037] S2: Add SBS to the oil phase system, heat and stir a second time until the SBS is completely swollen, to obtain a mixed viscous system, specifically: Add SBS to the oil phase system, keep the stirring speed at 3000-5000 r / min, raise the temperature to 175-185℃ at a heating rate of 4-6℃ / min, and continue stirring until the SBS is completely swollen (no visible particles, and the viscosity of the system rises to 200-300 Pa·s) to obtain a mixed viscous system.

[0038] S3: Add modified carbon powder to the mixed viscous system, cool and stir until the carbon powder is evenly dispersed, cool and mold to obtain microwave-sensitive asphalt recycling agent, specifically: Modified toner was added to the mixed viscous system, and the mixture was cooled to 85–95°C and stirred at a speed of 350–450 r / min until the toner was uniformly dispersed (the particle size D50 of the dispersed toner was ≤30 μm as measured by a laser particle size analyzer), resulting in a black, uniform, viscous system. The modified toner was prepared by mixing toner and KH550 silane coupling agent in an ethanol-water solution at a mass ratio of (90–110):2, with the volume ratio of ethanol to water in the ethanol-water solution being 9:1. After adding toner and KH550 silane coupling agent, the solid-liquid mass ratio was 1:5. The mixture was reacted at 55–75°C for 1.5–3 h and then dried to obtain the modified toner.

[0039] The temperature for cooling and stirring is 85–95°C, and the stirring speed is 350–450 r / min. The black, uniform, viscous system was removed from the reactor and allowed to cool naturally to room temperature (25°C) to avoid microstructural inhomogeneity caused by rapid cooling. The final product was a black, viscous microwave-sensitive regenerator (viscosity 5000-8000 mPa·s at 25°C).

[0040] To further illustrate the technical solution and beneficial effects of the present invention, specific embodiments are provided below. It should be noted that: In each embodiment: Vegetable oils: Grade 1 soybean oil (purchased from a certain company, acid value 0.3mgKOH / g, iodine value 130gI2 / 100g, moisture content ≤0.1%) or refined rapeseed oil (purchased from a certain bioenergy company, acid value 0.4mgKOH / g, iodine value 125gI2 / 100g, moisture content ≤0.1%) are selected. Both are mainly composed of unsaturated fatty acid glycerides, which can improve the low-temperature ductility of aged asphalt. Soybean oil has a higher linoleic acid content (50-60%), while rapeseed oil has a lower erucic acid content (≤3%), which is suitable for different low-temperature performance requirements.

[0041] SBS: Linear SBS (model YH-791, produced by a petrochemical company, molecular weight 120,000, styrene content 30%, melt index 2.5g / 10min (200℃, 5kg)) or star-shaped SBS (model YH-801, produced by a petrochemical company, molecular weight 180,000, styrene content 35%, melt index 1.8g / 10min (200℃, 5kg)) is selected. The linear structure is beneficial to improve low-temperature elasticity, while the star-shaped structure enhances high-temperature stability.

[0042] DBP: Analytical grade DBP (produced by a chemical reagent company, purity 99.5%, density 0.982 g / cm³) was selected. 3 (Boiling range 340-342℃), as a plasticizer, it can reduce the viscosity of the system and promote the swelling and dispersion of SBS.

[0043] Modified toner: Modified graphitized toner (produced by a new materials company, carbon content 99.8%, particle size D50=25μm, specific surface area 75m²) was selected. 2 / g), modified with KH550 silane coupling agent (modifier dosage 2%, ethanol-water mixed solvent (volume ratio 9:1), stirred in a constant temperature water bath at 60℃ for 2h, and dried at 80℃ for 4h), the contact angle of the toner surface decreased from 85° to 45° after modification, improving its compatibility with the organic phase.

[0044] The raw material ratios (parts by weight) and key parameters for each embodiment are shown in the table below:

[0045] The preparation conditions for each embodiment are shown in the table below:

[0046] The microwave-sensitive regenerants prepared in Examples 1-5 were subjected to performance tests. The test methods and results are as follows: Test items and methods Microwave heating performance: Using a 2KW KL-2D-6KW microwave heating device, 50g of regenerant was placed in a 50mL quartz beaker, and the real-time temperature within 0-5min was measured with an infrared thermometer (accuracy ±0.5℃), and the heating rate (℃ / min) was calculated.

[0047] Compatibility test: Mix the regenerator and aged asphalt (penetration 25℃, 25 (0.1mm)) at a mass ratio of 1:9, stir at 163℃ for 30min, take a sample of the mixture, observe the degree of phase separation under a fluorescence microscope (magnification 400×), and rate it according to 1-5 (1: completely homogeneous, no interface; 5: severe stratification, clear interface).

[0048] Conventional properties of recycled asphalt: Refer to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG 3410-2025) to test the penetration at 25℃ (T0604), softening point (T0606), and ductility at 5℃ (T0605) of aged asphalt after adding 10% recycling agent.

[0049] Road performance: The ratio of complex modulus to phase angle (G* / sinδ, T0628) at 60℃ was tested using a dynamic shear rheometer (DSR) to evaluate high-temperature rutting resistance; the stiffness modulus (S) and creep rate (m, T0627) at -12℃ were tested using a bending beam rheometer (BBR) to evaluate low-temperature crack resistance.

[0050] Test Results and Analysis The performance test results for each embodiment are shown in the table below:

[0051] As shown in the table above, the amount of toner has a significant impact on microwave heating performance: In Example 4, with 5 parts of toner, the heating rate reached 15.8℃ / min, but the compatibility rating dropped to level 4 (toner agglomeration) due to excessive dosage; in Example 5, with 1 part of toner, the heating rate was only 10.5℃ / min, indicating that heating efficiency and compatibility can be balanced within the range of 1-5 parts of toner. Increasing the SBS content (Examples 2 and 4) improved the system elasticity and increased G* / sinδ at 60℃ (enhanced high-temperature rutting resistance), but slightly reduced the ductility at 5℃ (stronger rigidity of the star-shaped structure); increasing the amount of vegetable oil (Examples 3 and 5) improved the low-temperature ductility, but slightly reduced the softening point. The best overall performance was achieved in Example 1 (80 parts vegetable oil, 15 parts linear SBS, and 3 parts toner), with a heating rate of 13.2℃ / min, compatibility level 1, and balanced road performance of the recycled asphalt.

[0052] The aforementioned microwave-sensitive asphalt rejuvenator is applied in asphalt pavement repair. During the asphalt pavement repair process, this microwave-sensitive asphalt rejuvenator can rapidly penetrate into the interior of the asphalt pavement under microwave action, achieving simultaneous internal and external heating, significantly shortening softening time and improving on-site work efficiency. After microwave heating and regeneration, the flexural tensile strength, breaking stiffness modulus, and breaking strain of the asphalt mixture are significantly improved, low-temperature flexibility is enhanced, effectively reducing thermal shrinkage cracks and fatigue cracks, and extending pavement service life. Simultaneously, the SBS component in the rejuvenator enhances the asphalt's high-temperature deformation resistance through rigid chain segments, reducing rutting and other defects, and adapting to heavy traffic demands. Compared to traditional methods, the microwave-sensitive rejuvenator can effectively improve the utilization rate of old materials, reduce the use of new materials, and lower material costs. Through its core advantages such as rapid softening, performance restoration, and economic and environmental friendliness, this microwave-sensitive asphalt rejuvenator solves the problems of low efficiency, high pollution, and high cost in traditional asphalt pavement repair, providing an efficient, green, and sustainable solution for road maintenance. Its application not only improves pavement quality and service life but also promotes technological upgrading in the highway industry, resulting in significant social and economic benefits.

[0053] This invention also relates to the field of microwave heating materials technology, focusing primarily on the regulation mechanisms of materials' microwave energy absorption characteristics, heating behavior, and energy conversion efficiency. It achieves rapid response and efficient heating of regenerators under microwave fields by introducing microwave-sensitive components. Furthermore, this invention is also related to the field of polymer composite materials technology, involving the regulation of interfacial compatibility, microstructure design, and synergistic optimization of macroscopic performance in multi-component systems (vegetable oil-based materials, elastomers, plasticizers, and functional powders). The aim is to improve the compatibility and overall performance of regenerators with aged asphalt through material composite technology. The specific application scenario for the microwave-sensitive regenerator of this invention is asphalt pavement recycling engineering, including two main processes: microwave in-situ recycling and microwave plant-mixed recycling. In-situ recycling is suitable for asphalt pavement repair projects where the base structure is intact and only the surface or intermediate layers show signs of aging, cracks, or other defects. It involves spraying a recycling agent on-site and using microwave heating equipment to soften and recycle the old asphalt mixture. Plant-mixed recycling is suitable for the centralized processing of large-scale milled asphalt pavement materials. It involves mixing and heating the recycling agent with the old asphalt mixture at a mixing plant to prepare recycled asphalt mixtures that meet road use requirements for new or expanded pavement projects. The microwave-sensitive recycling agent provided by this invention can effectively adapt to both recycling processes, improving heating efficiency and the performance stability of the recycled asphalt mixture.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A microwave-sensitive asphalt rejuvenator, characterized in that, The product comprises, by weight, 70-90 parts vegetable oil, 5-25 parts SBS, 0-4 parts DBP, and 1-5 parts modified toner, wherein the modified toner is toner modified with a silane coupling agent.

2. The microwave-sensitive asphalt rejuvenator according to claim 1, characterized in that, The vegetable oil has an acid value ≤0.5mgKOH / g, an iodine value of 120~140gI2 / 100g, and an unsaturated fatty acid glyceride content >95%.

3. The microwave-sensitive asphalt rejuvenator according to claim 1, characterized in that, The SBS has a molecular weight of 100,000 to 200,000 and a styrene content of 30% to 40%.

4. The microwave-sensitive asphalt rejuvenator according to claim 1, characterized in that, The modified toner is toner modified with KH550 silane coupling agent.

5. A method for preparing a microwave-sensitive asphalt rejuvenator as described in any one of claims 1-4, characterized in that, include: The vegetable oil and DBP were heated and stirred until they were evenly mixed to obtain the oil phase system. Add SBS to the oil phase system, heat and stir a second time until the SBS is completely swollen to obtain a mixed viscous system; Modified carbon powder is added to the mixed viscous system, and the mixture is cooled and stirred until the carbon powder is evenly dispersed. The mixture is then cooled and molded to obtain a microwave-sensitive asphalt rejuvenator.

6. The method for preparing microwave-sensitive asphalt rejuvenator according to claim 5, characterized in that, It also includes a vegetable oil pretreatment process, specifically: The vegetable oil was dehydrated by rotary evaporation at 90–110℃ and -0.1–-0.08 MPa until the moisture content in the vegetable oil was ≤0.1 wt%, thus completing the vegetable oil pretreatment process.

7. The method for preparing microwave-sensitive asphalt rejuvenator according to claim 5, characterized in that, The modified toner is prepared by: The toner and KH550 silane coupling agent were mixed in an ethanol aqueous solution at a mass ratio of (90-110):2, reacted at 55-75℃ for 1.5-3 hours, and dried to obtain the modified toner.

8. The method for preparing microwave-sensitive asphalt rejuvenator according to claim 5, characterized in that, The first stirring and heating temperature is 150-160℃, and the stirring speed is 3000-5000 r / min; the second stirring and heating temperature is 175-185℃, and the stirring speed is 3000-5000 r / min; the cooling and stirring temperature is 100-110℃, and the stirring speed is 3000-5000 r / min.

9. The method for preparing microwave-sensitive asphalt rejuvenator according to claim 5, characterized in that, The heating rate for the second heating and stirring is 4–6 °C / min.

10. The application of the microwave-sensitive asphalt rejuvenator according to any one of claims 1-4 in asphalt pavement repair.

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