SBS modified asphalt warm-mixing recycling agent, and preparation method and application thereof

Abstract

This invention discloses an SBS-modified asphalt warm-mix recycling agent, its preparation method, and its application, belonging to the field of asphalt pavement material recycling technology. The recycling agent, by mass percentage, comprises 57%–80% polymer composite recycling agent and 20%–43% warm-mix agent. The polymer composite recycling agent consists of recycled base oil, polymer supplements, and plasticizers, while the warm-mix agent contains lubricating and viscosity-reducing components and asphaltene dispersing components. The aforementioned warm-mix recycling agent can restore and improve the low-temperature crack resistance, high-temperature rutting resistance, and fatigue resistance of aged asphalt, achieving low-temperature mixing and reducing energy consumption and pollution.

Description

Technical Field

[0001] This invention belongs to the field of asphalt pavement material recycling technology, specifically relating to a recycling agent suitable for warm mix recycling of SBS modified asphalt, its preparation method and application. Background Technology

[0002] SBS (styrene-butadiene-styrene block copolymer) modified asphalt, with its excellent high-temperature stability, low-temperature crack resistance, and fatigue resistance, has become a key pavement material for important transportation facilities such as highways and urban arterial roads. However, during long-term use, SBS modified asphalt pavements are subjected to multiple factors such as high temperature, ultraviolet radiation, precipitation, and vehicle loads, leading to the oxidative polymerization of asphalt components and the fracture of the SBS polymer network structure. Ultimately, this results in rutting, cracking, and loosening, seriously affecting the quality of road traffic and its service life.

[0003] To address the maintenance challenges of aging SBS-modified asphalt pavements and reduce resource waste and environmental pollution, asphalt recycling technology has emerged. Traditional asphalt recycling techniques require heating the old asphalt mixture to 160℃~180℃ for mixing to ensure its fluidity and workability. However, this process has significant drawbacks: firstly, high-temperature heating consumes large amounts of fossil fuels such as coal and fuel oil, failing to meet energy conservation and environmental protection requirements; secondly, at high temperatures, asphalt releases harmful gases such as polycyclic aromatic hydrocarbons and volatile organic compounds (VOCs), polluting the atmosphere. Therefore, reducing the mixing temperature of asphalt recycling and developing warm-mix recycling technology have become key research directions in the industry.

[0004] In existing technologies, researchers have reduced asphalt viscosity by adding organic warm mix agents to achieve a warm mix effect. Although this can lower the mixing temperature by 20°C to 30°C, it generally has significant drawbacks: First, low-temperature performance is sacrificed. The addition of organic warm mix agents alters the intermolecular forces of asphalt, leading to a significant decrease in the low-temperature crack resistance of recycled asphalt, which can easily cause low-temperature cracking of pavement in cold regions. Second, the cost is high. Commonly used imported warm mix agents are expensive, significantly increasing the material costs of maintenance projects. Third, the recycling effect is limited. It can only achieve the function of reducing viscosity and warm mixing, but cannot effectively repair the damaged polymer network structure in aged SBS modified asphalt, nor can it solve the problem of hindered recycler penetration caused by the self-association and aggregation of asphaltenes in aged asphalt.

[0005] To address the aging characteristics of SBS-modified asphalt, existing recycling technologies also adjust the asphalt composition by adding light oils and supplementing SBS polymers to repair the network structure. However, these methods only focus on restoring the basic mechanical properties of asphalt and cannot achieve warm mix functionality, still requiring high-temperature mixing, thus failing to solve the problems of energy consumption and environmental pollution. Furthermore, some technologies attempt to simply mix warm mix agents with recycling agents, but because the compatibility and synergistic effects between the components are not considered, problems such as poor warm mix performance, unstable recycling performance, and further deterioration of low-temperature performance often occur, making it difficult to meet the comprehensive performance requirements of recycled asphalt in actual engineering projects.

[0006] Therefore, it is evident that how to restore the fatigue resistance and temperature resistance of SBS modified asphalt while ensuring warm mixing is an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides an SBS-modified asphalt warm mix regenerator, its preparation method, and its application. Through the synergistic compounding of polymer composite regenerator and warm mix agent, and the complementary functions of each component, the road performance of aged SBS-modified asphalt is fully restored and improved while reducing the recycling mixing temperature.

[0008] This invention provides an SBS modified asphalt warm mix regenerator, which, by mass percentage, comprises 57%~80% polymer composite regenerator and 20%~43% warm mix agent. The polymer composite regenerator contains regenerated base oil, polymer supplement and plasticizer, and the warm mix agent contains lubricating and viscosity-reducing components and asphaltene dispersing components.

[0009] When the warm-mix recycling agent is used for the recycling of SBS modified asphalt, it enables the recycled SBS modified asphalt to have a rotational viscosity ≤2100 mPa at 140°C. Low-temperature crack resistance (S / m value ≤ 460 MPa) at -18℃, and high-temperature rutting resistance (J) with irreversible creep compliance at 65℃. nr3.2 ≤1.2kPa -1 .

[0010] A ratio of 57%–80% polymer composite recycler and 20%–43% warm mix agent optimizes the synergistic effect between recycling performance and warm mix function. At this ratio, the polymer composite recycler can adequately replenish the light oil content of aged asphalt and repair the polymer network, while the plasticizer fully compensates for the low-temperature performance loss caused by warm mix. The warm mix agent effectively reduces viscosity to achieve low-temperature mixing, and the asphalt dispersion components open up the penetration channels of the recycler, preventing asphalt aggregates. If the proportion of polymer composite recycler is too low, the recycling function is insufficient, and performance recovery is incomplete; if it is too high, the warm mix effect weakens, and the asphalt viscosity increases, affecting construction. If the proportion of warm mix agent is too low, the viscosity-reducing and dispersion effects are poor, and effective warm mix cannot be achieved; if it is too high, it will weaken the high-temperature rutting resistance of asphalt.

[0011] Furthermore, the recycled base oil is at least one of waste edible vegetable oil, industrial vegetable oil residue, or animal and vegetable oil derivatives. Recycled base oils are widely available and inexpensive. Waste edible vegetable oil, as a waste product from the catering and food processing industries, reduces environmental pollution while achieving resource utilization. Its rich content of unsaturated fatty acid glycerides has good compatibility with asphalt, efficiently replenishing the light oil lost in aged asphalt, adjusting the asphalt component ratio, softening the aged asphalt matrix, and creating favorable conditions for subsequent polymer network repair. Industrial vegetable oil residue and animal and vegetable oil derivatives have more stable chemical properties, ensuring the consistency of the regenerator's performance and adapting to regeneration needs under different environments. The recycled base oil accounts for 55%~65% of the polymer composite regenerator by mass. This proportion ensures sufficient adjustment of the asphalt components and provides a good dispersion medium for polymer supplements and plasticizers, avoiding the decline in asphalt's high-temperature performance due to excessive recycled base oil, or the inability to achieve softening and component adjustment effects due to insufficient dosage.

[0012] Furthermore, the polymer supplement is at least one of styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, or hydrogenated styrene-butadiene block copolymer. These block copolymers have similar molecular structures to the polymers remaining in aged SBS-modified asphalt, and can form a synergistic effect through molecular chain entanglement, precisely repairing the damaged three-dimensional polymer network structure and restoring the asphalt's elastic recovery and fatigue resistance. Among them, styrene-butadiene-styrene block copolymer has the best compatibility with traditional SBS-modified asphalt, styrene-isoprene-styrene block copolymer has better low-temperature performance, and hydrogenated styrene-butadiene block copolymer has stronger aging resistance, allowing for flexible selection based on different climatic regions and application requirements. The polymer supplement accounts for 15%~20% of the polymer composite regenerator by mass. This proportion ensures sufficient polymer network repair while avoiding excessive polymer leading to increased asphalt viscosity, which would affect warm-mix performance and workability.

[0013] Further, the plasticizer is at least one of adipate plasticizers, phthalate plasticizers, or sebacic acid ester plasticizers.

[0014] The role of plasticizers is to compensate for the low-temperature performance loss caused by organic warm mix additives, while enhancing the plasticity and flexibility of asphalt. Their long and flexible molecular chains have similar chemical structures to the gums and aromatics in asphalt, exhibiting excellent compatibility. They can easily insert themselves between asphalt molecules, acting as a barrier and lubricant, reducing internal friction between asphalt molecules, and increasing the spatial freedom of gums and asphaltenes, thereby significantly improving the low-temperature flexibility and crack resistance of asphalt. Adipate plasticizers are particularly excellent in low-temperature performance, phthalate plasticizers exhibit outstanding compatibility and stability, while sebacic acid ester plasticizers combine good high-temperature resistance and weather resistance, and can be rationally combined according to the application environment and performance requirements. The mass percentage of the plasticizer in the polymer composite regenerator is 20%~25%. This ratio ensures sufficient plasticizing effect while avoiding the decline in high-temperature performance and anti-aging properties of asphalt due to excessive plasticizer.

[0015] Further, the adipate ester plasticizer is at least one of dioctyl adipate, diisooctyl adipate, dibutyl adipate, or diisobutyl adipate.

[0016] These plasticizers are characterized by high molecular chain flexibility, good compatibility with asphalt, and significant low-temperature plasticizing effect. Among them, dioctyl adipate (DOA) has the best overall performance. The long-chain alkyl groups in its molecular structure can form a stable interaction with asphalt molecules, reducing the low-temperature embrittlement temperature of asphalt without affecting its high-temperature stability. It is the preferred type of plasticizer in this invention. Other adipate ester plasticizers can be flexibly replaced according to engineering costs and performance requirements, and all can effectively improve the low-temperature performance of asphalt.

[0017] Furthermore, the lubricating and viscosity-reducing component is at least one of vinyl bis-stearamide, vinyl bis-palmitamide, or long-chain fatty acid amide compounds. These compounds have specific melting points and melt rapidly at the asphalt mixing temperature, forming a uniform lubricating film that adsorbs onto the surface of asphalt molecules. This significantly reduces the friction and cohesion between asphalt molecules, thereby achieving a highly efficient viscosity-reducing warm-mix effect, lowering the mixing temperature, and greatly reducing energy consumption and harmful gas emissions. The polar amides of these components can form electrostatic attraction with the polar groups of asphaltene, ensuring their stable dispersion in the asphalt system, preventing stratification and precipitation, and improving the storage stability and reliability of recycled asphalt. The mass percentage of the lubricating and viscosity-reducing component in the warm-mix agent is 60%~70%. This proportion ensures sufficient viscosity-reducing effect while providing a good dispersion basis for the asphaltene dispersion components, avoiding the impact of excessive lubricating and viscosity-reducing components on the low-temperature performance of asphalt.

[0018] Further, the asphaltene dispersion component is at least one of polyisobutylene succinimide, polyisobutylene succinic anhydride, or polyolefin-based succinimide derivatives.

[0019] In aged SBS modified asphalt, asphaltenes easily aggregate due to intermolecular hydrogen bonding, forming large aggregates that hinder the penetration and diffusion of the recycling agent, leading to uneven recycling results. This type of dispersion component possesses a unique "polar-nonpolar" amphiphilic structure: the polar amide forms hydrogen bonds with the hydroxyl groups on the surface of asphaltenes molecules, firmly adsorbing onto the surface of the asphaltenes aggregates; the nonpolar polyisobutylene long chains extend into the surrounding oil phase environment, creating a steric hindrance effect, preventing asphaltenes molecules from further approaching, aggregating, and depositing. This disperses the large asphaltenes aggregates into smaller particles, opening up the penetration channels of the recycling agent in the aged asphalt, ensuring uniform diffusion of the recycling agent throughout the asphalt system, and improving the uniformity and stability of recycling performance. Simultaneously, the nonpolar long chains also play a role in reducing viscosity, further optimizing the warm mix effect. The mass percentage of the asphaltenes dispersion component in the warm mix agent is 30%~40%. This ratio achieves a synergistic effect of asphaltenes dispersion and viscosity reduction, avoiding a decrease in the high-temperature performance of the asphalt due to excessive dispersion components.

[0020] Furthermore, the SBS modified asphalt warm-mix recycling agent also includes functional additives, which are at least one of antioxidants, ultraviolet absorbers, or stabilizers. Adding functional additives can enhance the long-term performance of recycled asphalt from multiple dimensions: antioxidants can inhibit the oxidative aging reaction of asphalt during use, delay the deterioration of asphalt components, and extend the service life of recycled asphalt; ultraviolet absorbers can absorb ultraviolet energy, reduce the damage of ultraviolet rays to the SBS polymer molecular chains, and protect the integrity of the polymer network structure; stabilizers can enhance the compatibility and stability between components, avoid stratification and segregation of recycled asphalt during storage and use, and ensure stable performance. The mass percentage of the functional additives does not exceed 5% of the total mass of the SBS modified asphalt warm-mix recycling agent. This dosage range ensures that the functional additives play a full role without affecting the main properties of the asphalt due to excessive dosage, achieving a balance between performance enhancement and cost control.

[0021] Preferably, the present invention provides an SBS modified asphalt warm mix regenerator, which, by mass percentage, is composed of 57%~80% polymer composite regenerator and 20%~43% warm mix agent. Preferably, the polymer composite regenerator is composed of regenerated base oil, polymer supplement and plasticizer, and the warm mix agent is composed of lubricating and viscosity-reducing components and asphaltene dispersing components.

[0022] Further preferred options include recycled edible vegetable oil as the base oil, styrene-butadiene-styrene block copolymer as the polymer supplement, dioctyl adipate as the plasticizer, vinyl bis-stearamide as the lubricating and viscosity-reducing component, and polyisobutylene succinimide as the asphaltene dispersion component.

[0023] This invention also provides a method for preparing SBS-modified asphalt warm mix recycling agent, characterized by comprising the following steps: S1: Weigh out the recycled base oil, polymer supplement, plasticizer, lubricating and viscosity-reducing components, asphaltene dispersion components, and optional functional additives according to the mass percentage for later use; S2: Mix the lubricating and viscosity-reducing components with the asphalt dispersion components until homogeneous to obtain a warm mix admixture; S3: Heat the recycled base oil to 130℃~150℃, add polymer supplement and soak for 8min~12min, then add plasticizer and shear at 2000rpm~3000rpm for 10min~20min to obtain polymer composite regenerator; S4: Add the warm mix agent and functional additives to the polymer composite recycling agent, and shear at a speed of 400 rpm to 600 rpm for 3 min to 8 min to obtain SBS modified asphalt warm mix recycling agent.

[0024] Furthermore, in step S2, the stirring temperature is 60℃~80℃, and the stirring time is 15min~30min. The above temperatures ensure that the lubricating and viscosity-reducing components are in a softened state, with enhanced molecular activity, facilitating thorough mixing with the asphaltene dispersion components, while preventing excessive temperature from causing component volatilization or changes in chemical properties. The above stirring time ensures that the two components form a uniform and stable mixture, avoiding fluctuations in the warm-mixing and dispersion effects due to uneven mixing. This lays a good foundation for subsequent compounding with the polymer composite regenerator, ensuring the consistency and reliability of the final product performance.

[0025] The settings of heating temperature, soaking time, rotation speed, and shearing time in step S3 directly determine the performance of the polymer composite regenerator. Matching the heating temperature with the softening temperature of the polymer supplement avoids insufficient polymer swelling and residual solid particles due to excessively low temperatures, or oxidative polymerization of unsaturated fatty acid glycerides in the regenerated base oil and increased viscosity due to excessively high temperatures. This temperature also enhances the activity of plasticizer molecules, allowing them to quickly penetrate the swollen polymer molecular chains and the regenerated base oil system, fully exerting their isolating and lubricating effects. Soaking the polymer supplement for 8-12 minutes allows the regenerated base oil to gradually penetrate into the polymer supplement, ensuring the polymer molecular chains fully expand. This guarantees that the polymer can be uniformly dispersed to form a dense three-dimensional network structure during subsequent shearing, while reducing localized agglomeration after shearing due to insufficient soaking time, or prolonged preparation cycle and slight degradation of polymer molecular chains due to excessive soaking time. The strong shear force generated by a shearing speed of 2000 rpm to 3000 rpm and a shearing time of 10 min to 20 min can break the swollen polymer particles into micro-nano sizes, allowing them to be uniformly dispersed in the recycled base oil and plasticizer system, forming a continuous and stable polymer network. This avoids the problem of insufficient shear force due to too low a speed or insufficient shearing time, which would result in the formation of large agglomerates due to ineffective particle breaking, or the problem of energy waste and excessive polymer chain breakage due to too high a speed or too long shearing time. At the same time, the strong shear force can promote the deep integration of plasticizer with recycled base oil and polymer supplements, ensuring uniform distribution of plasticizer and fully exerting its role in improving the low-temperature flexibility of asphalt.

[0026] Furthermore, in step S3, the heating rate of the regenerated base oil is 5℃ / min to 10℃ / min. Controlling the heating rate effectively prevents the regenerated base oil from oxidizing and deteriorating due to local overheating, ensuring its stable performance. A heating rate of 5℃ / min to 10℃ / min ensures that the regenerated base oil can quickly reach the target temperature, improving preparation efficiency, while also ensuring that the temperature of the regenerated base oil rises uniformly, avoiding excessively high local temperatures that could lead to oxidative polymerization of the oil and affect its conditioning effect on the asphalt components. At the same time, the uniform heating process provides good conditions for the full soaking of the polymer supplement, allowing the polymer supplement to gradually swell and ensuring uniform dispersion during subsequent shearing, forming a continuous polymer network structure.

[0027] The present invention also provides an application of the above-mentioned SBS modified asphalt warm mix recycling agent in SBS modified asphalt.

[0028] The beneficial effects of this application are as follows: 1. The warm-mix regenerator provided by this invention uses recycled base oil to replenish the light oil lost in aged asphalt, adjust the asphalt component ratio, soften the aged asphalt matrix, and create a favorable environment for polymer network repair. The polymer supplement entangles with the polymer molecules remaining in the aged asphalt, reconstructs the three-dimensional network structure, and improves the elasticity and fatigue resistance of the asphalt. The two achieve asphalt regeneration from both component and structural levels, providing a performance basis for the realization of the warm-mix function.

[0029] 2. The lubricating and viscosity-reducing components reduce the viscosity of asphalt by forming a lubricating film, thus achieving a warm-mix effect; the plasticizer enhances plasticity by inserting itself between asphalt molecules, precisely compensating for the loss of performance at low temperatures. The two work synergistically to achieve "no reduction in efficiency during warm mixing", ensuring that recycled asphalt has both excellent warm-mix workability and low-temperature crack resistance.

[0030] 3. The lubricating and viscosity-reducing components directly reduce the viscosity of asphalt, providing favorable conditions for the penetration of the recycling agent; the asphalt dispersion components disperse asphalt aggregates, avoiding the asphalt aggregates' obstruction of penetration. The two work together to improve the penetration efficiency and uniformity of the recycling agent, ensuring that the recycling agent is evenly diffused throughout the entire asphalt system, achieving a uniform recycling effect. Detailed Implementation

[0031] The embodiments described in this invention are merely some, not all, of the embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are within the scope of protection of this application.

[0032] Example 1 An SBS-modified asphalt warm mix recycler, by weight percentage, is composed of 80% polymer composite recycler and 20% warm mix agent; wherein, by weight percentage, the polymer composite recycler contains 60% waste edible vegetable oil, 18% styrene-butadiene-styrene block copolymer, and 22% dioctyl adipate (DOA); the warm mix agent contains 65% vinyl bis-stearamide and 35% polyisobutylene succinimide.

[0033] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, dioctyl adipate, vinyl bis-stearamide, and polyisobutylene succinimide according to the above mass percentages, and set aside for later use; S2: Add vinyl bis-stearamide and polyisobutylene succinimide to a mixing tank, mix and stir evenly to obtain a warm mixing agent; S3: Heat waste edible vegetable oil to 140℃, add styrene-butadiene-styrene block copolymer and soak for 10 min, then add dioctyl adipate and shear at 2500 rpm for 15 min to obtain polymer composite regenerator. S4: Pour the warm mix agent obtained in step S2 into the polymer composite regenerator obtained in step S3, and shear at 500 rpm for 5 minutes to finally obtain the SBS modified asphalt warm mix regenerator.

[0034] Preparation of recycled asphalt: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 min and an aging container at 100℃ and 2.1MPa pressure for 20 h), add 5 parts of the above SBS modified asphalt warm mix recycling agent, and stir for 30 min at 140℃ and 1000 rpm to obtain recycled SBS modified asphalt.

[0035] Example 2 An SBS-modified asphalt warm mix recycler, by mass percentage, is composed of 67% polymer composite recycler and 33% warm mix agent; wherein, by mass percentage, the polymer composite recycler contains 60% waste edible vegetable oil, 18% styrene-butadiene-styrene block copolymer, and 22% dioctyl adipate (DOA); the warm mix agent contains 65% vinyl bis-stearamide and 35% polyisobutylene succinimide.

[0036] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, dioctyl adipate, vinyl bis-stearamide, and polyisobutylene succinimide according to the above mass percentages, and set aside for later use; S2: Add vinyl bis-stearamide and polyisobutylene succinimide to a mixing tank, mix and stir evenly to obtain a warm mixing agent; S3: Heat waste edible vegetable oil to 140℃, add styrene-butadiene-styrene block copolymer and soak for 10 min, then add dioctyl adipate and shear at 2500 rpm for 15 min to obtain polymer composite regenerator. S4: Pour the warm mix agent obtained in step S2 into the polymer composite regenerator obtained in step S3, and shear at 500 rpm for 5 minutes to finally obtain the SBS modified asphalt warm mix regenerator.

[0037] Preparation of recycled asphalt: Take 100 parts of aged SBS modified asphalt (preparation method is the same as in Example 1), add 6 parts of the above-mentioned SBS modified asphalt warm mix recycling agent, and stir for 30 minutes at 140℃ and 1000rpm to obtain recycled SBS modified asphalt.

[0038] Example 3 An SBS-modified asphalt warm mix recycler, by weight percentage, is composed of 57.1% polymer composite recycler and 42.9% warm mix agent; wherein, by weight percentage, the polymer composite recycler contains 60% waste edible vegetable oil, 18% styrene-butadiene-styrene block copolymer, and 22% dioctyl adipate (DOA); and the warm mix agent contains 65% vinyl bis-stearamide and 35% polyisobutylene succinimide.

[0039] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, dioctyl adipate, vinyl bis-stearamide, and polyisobutylene succinimide according to the above mass percentages, and set aside for later use; S2: Add vinyl bis-stearamide and polyisobutylene succinimide to a mixing tank, mix and stir evenly to obtain a warm mixing agent; S3: Heat waste edible vegetable oil to 140℃, add styrene-butadiene-styrene block copolymer and soak for 10 min, then add dioctyl adipate and shear at 2500 rpm for 15 min to obtain polymer composite regenerator. S4: Pour the warm mix agent obtained in step S2 into the polymer composite regenerator obtained in step S3, and shear at 500 rpm for 5 minutes to finally obtain the SBS modified asphalt warm mix regenerator.

[0040] Preparation of recycled asphalt: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 min and an aging container at 100℃ and 2.1MPa pressure for 20 h), add 7 parts of the above SBS modified asphalt warm mix recycling agent, and stir for 30 min at 140℃ and 1000 rpm to obtain recycled SBS modified asphalt.

[0041] Example 4 An SBS-modified asphalt warm mix recycler, by mass percentage, is composed of 75% polymer composite recycler and 25% warm mix agent; wherein, by mass percentage, the polymer composite recycler contains 62% waste edible vegetable oil, 17% styrene-butadiene-styrene block copolymer, and 21% diisooctyl adipate; the warm mix agent contains 68% vinyl bispalmitamide and 32% polyisobutylene succinic anhydride.

[0042] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, diisooctyl adipate, vinyl bispalmitamide, and polyisobutylene succinic anhydride according to the above mass percentages, and set aside for later use; S2: Add vinyl bispalmitamide to polyisobutylene succinic anhydride, mix and stir evenly to obtain a warm mix agent; S3: Heat waste edible vegetable oil to 140℃, then immerse the styrene-butadiene-styrene block copolymer in the waste edible vegetable oil for 10 minutes, then add diisooctyl adipate to the waste edible vegetable oil and shear at 2500 rpm for 15 minutes to obtain a polymer composite regenerator. S4: Pour the warm mix agent into the polymer composite recycling agent and shear at 500 rpm for 5 minutes to obtain the SBS modified asphalt warm mix recycling agent.

[0043] Preparation of recycled asphalt: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 min and an aging container at 100℃ and 2.1MPa pressure for 20 h), add 5.3 parts of the above SBS modified asphalt warm mix recycling agent, and stir for 30 min at 140℃ and 1000 rpm to obtain recycled SBS modified asphalt.

[0044] Comparative Example 1 Unaged SBS modified bitumen was used as a performance reference.

[0045] Comparative Example 2 A polymer composite regenerator, by mass percentage, comprises 60% waste edible vegetable oil, 18% styrene-butadiene-styrene block copolymer, and 22% dioctyl adipate (DOA).

[0046] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, and dioctyl adipate according to the above mass percentages, and set aside; S2: Heat waste edible vegetable oil to 140℃, add styrene-butadiene-styrene block copolymer and soak for 10 min, then add dioctyl adipate and shear at 2500 rpm for 15 min to obtain polymer composite regenerator. Preparation of recycled asphalt: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 min and an aging container at 100℃ and 2.1MPa pressure for 20 h), add 4 parts of the above polymer composite regenerator, and stir for 30 min at 140℃ and 1000 rpm to obtain recycled SBS modified asphalt.

[0047] Comparative Example 3 A mixed component for warm-mix recycling, by mass percentage, consists of 47.1% waste edible vegetable oil, 14.2% styrene-butadiene-styrene block copolymer, and 38.7% warm-mix agent; wherein the warm-mix agent, by mass percentage, contains 65% vinyl bis-stearamide and 35% polyisobutylene succinimide.

[0048] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, dioctyl adipate, vinyl bis-stearamide, and polyisobutylene succinimide according to the above mass percentages, and set aside. S2: Add vinyl bis-stearamide to polyisobutylene succinimide, mix and stir evenly to obtain a warm mix agent; S3: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 minutes and an aging container at 100℃ and 2.1MPa pressure for 20 hours), add 5.2 parts of the above mixed components (composed of waste edible vegetable oil, dioctyl adipate and the warm mix agent prepared in step S2), and stir at 140℃ and 1000rpm for 30 minutes to obtain warm mix recycled SBS modified asphalt.

[0049] Comparative Example 4 A mixed component for warm-mix recycling, by mass percentage, consists of 75.7% polymer composite regenerator and 24.3% vinyl bis-stearamide; wherein, the polymer composite regenerator, by mass percentage, contains 60% waste edible vegetable oil, 18% styrene-butadiene-styrene block copolymer, and 22% dioctyl adipate (DOA).

[0050] Its preparation method includes the following steps: S1: Weigh out the waste edible vegetable oil, styrene-butadiene-styrene block copolymer, dioctyl adipate, and vinyl bis-stearamide according to the above mass percentages, and set aside; S2: Heat waste edible vegetable oil to 140℃, add styrene-butadiene-styrene block copolymer and soak for 10 min, then add dioctyl adipate and shear at 2500 rpm for 15 min to obtain polymer composite regenerator. S3: Take 100 parts of aged SBS modified asphalt (prepared by heating in a rotating film oven at 163℃ for 85 minutes and an aging container at 100℃ and 2.1MPa pressure for 20 hours), add 5.3 parts of the above mixed components (composed of polymer composite regenerator and vinyl bis-stearamide), and stir at 140℃ and 1000rpm for 30 minutes to obtain warm-mix recycled SBS modified asphalt.

[0051] All performance tests involved in the embodiments and comparative examples were performed according to the following standards: Fatigue performance: The fatigue factor G at 25°C was tested using a dynamic shear rheometer (DSR) according to AASHTOT-315 standard. sinδ (MPa), G The smaller the sinδ value, the better the fatigue performance, indicating that the asphalt has a stronger ability to resist repeated loading. Low-temperature crack resistance: According to the AASHTOT-313 standard, the S / m value (MPa) at -18℃ was tested using a bending beam rheometer (BBR). The smaller the S / m value, the better the low-temperature crack resistance, indicating that the asphalt has better flexibility and stronger crack resistance in low-temperature environments. High-temperature rutting resistance: According to AASHTOT-350 standard, the non-recoverable creep compliance J at 65°C was tested using a dynamic shear rheometer (DSR). nr3.2 (kPa) -1 ), J nr3.2 The smaller the value, the better the high-temperature rutting resistance, indicating that the asphalt has a stronger resistance to deformation at high temperatures; Rotational viscosity: The rotational viscosity (mPa) at 140°C was tested using a rotational viscometer according to AASHTOT-316 standard. (s) The lower the viscosity value, the better the warm mix construction performance, indicating better asphalt fluidity, which is more conducive to mixing and paving construction; Preparation of aged SBS modified bitumen: It was prepared by heating in a 163℃ rotating thin film oven (RTFOT) for 85 min and then in a 100℃, 2.1MPa pressure aging vessel (PAV) for 20 h to simulate the severe aging state after long-term service, ensuring the rigor and authenticity of the regeneration performance test.

[0052] Performance Test Results and Analysis The performance test results of recycled SBS modified asphalt in Examples 1-4 and Comparative Examples 1-4 are shown in the table below: Table 1. Performance test results of recycled SBS modified asphalt in Examples 1-4 and Comparative Examples 1-4

[0053] Examples 1-4 exhibit excellent overall performance; the rotational viscosity of the recycled asphalt in all examples is ≤2100 mPa at 140°C. The S / m value at -18℃ is ≤460MPa, and the J at 65℃ is ≤460MPa. nr3.2 All values ​​are ≤1.2 kPa -1 Among them, Example 2 showed the best overall performance, with a fatigue factor G. The sinδ is 0.678 MPa, close to that of the unaged asphalt in Comparative Example 1; the low-temperature crack resistance S / m is 332.156 MPa, superior to the unaged asphalt in Comparative Example 1; and the high-temperature rutting resistance J... nr3.2 0.896 kPa -1 It is also superior to the unaged asphalt in Comparative Example 1, with a rotational viscosity of 1875 mPa. The performance of the styrene-butadiene-styrene block copolymer and diisooctyl adipate reached or exceeded the level of unaged asphalt, demonstrating the synergistic effect of styrene-butadiene-styrene block copolymer and diisooctyl adipate in terms of temperature resistance.

[0054] Compared with Comparative Example 1, Comparative Example 2 has a rotational viscosity as high as 2870 mPa. Example 1 requires high-temperature mixing at 160℃ to ensure workability, which not only consumes a large amount of energy but also accelerates asphalt aging. Furthermore, its high-temperature rutting resistance is inferior to Example 1, demonstrating that the warm-mix admixture not only effectively reduces viscosity to achieve warm mixing but also synergistically improves the high-temperature performance of asphalt. Comparative Example 3, lacking a plasticizer, exhibits a significantly deteriorated fatigue factor, and its low-temperature crack resistance S / m value far exceeds 460MPa, proving that plasticizers are key to improving the low-temperature resistance and fatigue resistance of asphalt. Comparative Example 4, lacking polyisobutylene succinimide, has a higher fatigue factor than Example 1, but its low-temperature S / m value is slightly inferior, indicating that the dispersing component can promote the penetration of the regenerator, optimize the internal structure, and improve overall performance.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. An SBS-modified asphalt warm mix recycling agent, characterized in that, By mass percentage, it comprises 57% to 80% polymer composite regenerator and 20% to 43% warm mix agent, wherein the polymer composite regenerator contains regenerated base oil, polymer supplement and plasticizer, and the warm mix agent contains lubricating and viscosity-reducing components and asphaltenes dispersing components; When the warm-mix recycling agent is used for the recycling of SBS modified asphalt, it enables the recycled SBS modified asphalt to have a rotational viscosity ≤2100 mPa at 140°C. Low-temperature crack resistance (S / m value ≤ 460 MPa) at -18℃, and high-temperature rutting resistance (J) with irreversible creep compliance at 65℃. nr3.2 ≤1.2kPa -1 .

2. The SBS-modified asphalt warm mix recycling agent according to claim 1, characterized in that, The recycled base oil is at least one of waste edible vegetable oil, industrial vegetable oil residue, or animal and vegetable oil derivatives, and the mass percentage of the recycled base oil in the polymer composite regenerator is 55% to 65%.

3. The SBS-modified asphalt warm-mix recycling agent according to claim 1, characterized in that, The polymer supplement is at least one of styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, or hydrogenated styrene-butadiene block copolymer, and the polymer supplement accounts for 15% to 20% of the polymer composite regenerator by mass.

4. The SBS-modified asphalt warm-mix recycling agent according to claim 1, characterized in that, The plasticizer is at least one of adipate plasticizer, phthalate plasticizer or sebacic acid ester plasticizer, and the mass percentage of the plasticizer in the polymer composite regenerator is 20% to 25%.

5. The SBS-modified asphalt warm-mix recycling agent according to claim 4, characterized in that, The adipate ester plasticizer is at least one of dioctyl adipate, diisooctyl adipate, dibutyl adipate, or diisobutyl adipate.

6. The SBS-modified asphalt warm-mix recycling agent according to claim 1, characterized in that, The lubricating and viscosity-reducing component is at least one of vinyl bis-stearamide, vinyl bis-palmitamide, or long-chain fatty acid amide compounds, and the mass percentage of the lubricating and viscosity-reducing component in the warm mix agent is 60% to 70%.

7. The SBS-modified asphalt warm-mix recycling agent according to claim 1, characterized in that, The asphaltene dispersion component is at least one of polyisobutylene succinimide, polyisobutylene succinic anhydride, or polyolefin-based succinimide derivatives, and the mass percentage of the asphaltene dispersion component in the warm mix agent is 30% to 40%.

8. The SBS-modified asphalt warm-mix recycling agent according to any one of claims 1 to 7, characterized in that, It also includes functional additives, which are at least one of antioxidants, ultraviolet absorbers, or stabilizers, and the mass percentage of the functional additives does not exceed 5% of the total mass of the SBS modified asphalt warm mix recycling agent.

9. A method for preparing an SBS-modified asphalt warm-mix recycling agent, characterized in that, Includes the following steps S1: Weigh out the recycled base oil, polymer supplement, plasticizer, lubricating and viscosity-reducing components, asphaltene dispersing components, and functional additives according to the mass percentage and set aside; S2: Mix the lubricating and viscosity-reducing components with the asphalt dispersion components until homogeneous to obtain a warm mix admixture; S3: Heat the recycled base oil to 130℃~150℃, add polymer supplement and soak for 8min~12min, then add plasticizer and shear at 2000rpm~3000rpm for 10min~20min to obtain polymer composite regenerator; S4: Add the warm mix agent and functional additives to the polymer composite regenerator, and shear at a speed of 400 rpm to 600 rpm for 3 min to 8 min to obtain SBS modified asphalt warm mix regenerator.

10. The application of an SBS modified asphalt warm mix recycling agent as described in claims 1-8 or an SBS modified asphalt warm mix recycling agent prepared by the preparation method described in claim 9 in SBS modified asphalt.

Images