Waste asphalt regenerant, large-proportion waste asphalt containing waste asphalt regenerant and preparation method of waste asphalt regenerant

Abstract

The invention relates to the technical field of waste asphalt regeneration, and particularly discloses a waste asphalt regenerant, large-proportion waste asphalt containing the waste asphalt regenerant and a preparation method of the waste asphalt regenerant and the large-proportion waste asphalt. The waste asphalt regenerant is prepared from the following raw materials: 45 to 55 percent of epoxidized illegal cooking oil, 15 to 20 percent of furfural refined oil, 8 to 12 percent of methyl carbamate, 3 to 5 percent of nano mica powder, 10 to 15 percent of desulfurized rubber powder and 5 to 8 percent of SEBS (Styrene-Ethylene-Butylene-Styrene) modifier. The waste asphalt regenerant has a three-dimensional network structure which is subjected to polar bonding; the large-proportion waste asphalt is prepared from the following components in parts by mass: 70 to 90 parts of waste asphalt, 15 to 25 parts of limestone sand, 10.5 to 18 parts of waste asphalt regenerant, 1 to 5 parts of new asphalt and 0.05 to 0.15 part of long-chain aliphatic hydrocarbon warm mixing agent. The regenerant can act in molecules of the waste asphalt, a stable space structure with elasticity and a three-dimensional network is formed through the synergistic effect of multiple components, and good low-temperature crack resistance and performance stability are kept after the waste asphalt is regenerated through the chemical bond effect among the components.

Description

Technical Field

[0001] The present invention relates to the technical field of regenerated waste asphalt, and in particular to a waste asphalt regeneration agent, a large proportion of waste asphalt containing the same, and a preparation method thereof. Background Art

[0002] High-proportion waste asphalt refers to asphalt in which recycled asphalt pavement (RAP) accounts for a high proportion of the fresh asphalt mix during the recycling process. Specifically, asphalt mixtures with RAP content of 20-50% or even higher are generally considered high-proportion waste asphalt. Recycled asphalt pavement (RAP) is an asphalt mixture made by reclaiming, recycling, crushing, and screening old asphalt pavement, then remixing it with a regeneration agent, new asphalt materials, and new aggregate in a specific proportion. The aged asphalt in waste asphalt has high hardness and viscosity, and its inclusion improves the mixture's rutting resistance. It is particularly suitable for use in hot climates or on heavily loaded roads, reducing the risk of summer pavement deformation. It also significantly reduces the use of new asphalt and aggregate, reduces mining and asphalt production, and lowers carbon emissions. It is a crucial asphalt production and use method under the current green development concept.

[0003] For example, patent publication number CN112456865A proposes a high-rutting-resistance, high-proportion recycled asphalt mixture and its preparation method. The mixture comprises the following components: 29-48 parts limestone, 1-2 parts filler, 50-70 parts recycled asphalt, 1.4-2.8 parts warm-mix asphalt, 0.05-0.15 parts modified regeneration agent, and 0.3-0.5 parts anti-rutting agent. The modified regeneration agent comprises base oil, a retarder, and a tackifying resin, with the weight ratio of base oil, retarder, and tackifying resin being 1:(0.08-0.1):(0.02-0.04). The warm-mix asphalt comprises asphalt and warm-mix agent in a weight ratio of 1:(0.1-0.12). By using a high content of waste asphalt (over 50%), combined with the regeneration agent and anti-rutting agent, the recycled asphalt mixture's plastic deformation capacity at high temperatures is reduced, thereby improving the high-temperature stability and rutting resistance of the recycled asphalt mixture.

[0004] The core function of the regeneration agent in high-proportion waste asphalt is to reverse and slow the aging process of asphalt, restoring the rheological properties of the waste asphalt through chemical or physical effects, thereby reducing the impact and limitations of high waste asphalt content on the performance of asphalt mixtures. However, in existing high-rutting-resistance, high-proportion recycled asphalt mixtures, such as the aforementioned, when the waste asphalt content exceeds 50wt%, the low-temperature cracking resistance of the asphalt mixture deteriorates significantly, resulting in severe freeze cracking and poor cold resistance in cold environments such as northern China. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that when the content of waste asphalt exceeds 50wt%, the low-temperature crack resistance of asphalt mixture decreases significantly and it is very easy to freeze and crack in cold environment.

[0006] The present invention is achieved through the following technical solutions: The present invention provides a waste asphalt regeneration agent. The raw materials for preparing the waste asphalt regeneration agent include the following components, calculated by mass fraction: 45-55% of epoxidized waste cooking oil, 15-20% of furfural refined oil, 8-12% of methyl carbamate, 3-5% of nano-mica powder, 10-15% of desulfurized rubber powder, and 5-8% of a SEBS modifier. Preferably, the particle size of the nano-mica powder is ≤5 μm.

[0007] The present invention provides a method for preparing the above-mentioned waste asphalt regeneration agent, comprising the following steps: S1: Epoxidized waste cooking oil is heated to 90±20°C to reduce its viscosity from approximately 850 mPa·s to 120 mPa·s, thereby reducing the steric hindrance of the epoxy groups and increasing their activity. In this state, furfural refined oil is added and stirred to form a base oil phase. The polar epoxy groups of the epoxidized waste cooking oil and the large π bonds of the aromatic hydrocarbons of the furfural refined oil interact through dipole-π interactions to form a stable composite carrier. S2: Add methyl carbamate to the base oil phase, heat to 130±20°C, and stir. The isocyanate groups in the methyl carbamate attack the epoxy groups of the epoxidized waste oil at high temperature, causing a ring-opening reaction to form an oxazolidinone structure, which gives the regeneration agent a strong polar interface. Then cool to 100±10°C, add the SEBS modifier, and stir to obtain a composite regeneration gel. The SEBS swells in the furfural refined oil, and the styrene blocks form physical crosslinking points, forming a spatial network structure. S3 The composite regeneration gel is kept warm at 100±10°C, and then desulfurized rubber powder is added and stirred. The composite regeneration gel and desulfurized rubber powder are in contact and bonded with each other, so that the pores on the surface of the desulfurized rubber powder are fully filled, and the thiol groups on the surface of the desulfurized rubber powder react and bond with the double bonds of the SEBS modifier to form an -S-CH2-CH2- structure, forming a highly stable elastic SEBS network structure, thereby improving the loss factor of the regeneration agent, extending the ductility of a large proportion of waste asphalt, and improving crack resistance; and nano-mica powder is added and stirred again to obtain the waste asphalt regeneration agent, in which the long-chain alkyl groups of the epoxidized waste oil are inserted between the mica layers, the interlayer spacing is expanded, the diffusion path of oxygen and the like can be extended, the oxidation induction period is extended, and a long-term anti-aging effect can be exerted.

[0008] Preferably, in step S2, after adding the desulfurized rubber powder and after adding the nano-mica powder, the stirring speed is 1000±100 rpm, and the stirring time is 30-60 min.

[0009] Preferably, in step S3, the desulfurized rubber powder is pretreated as follows before addition: the desulfurized rubber powder is heated to 120±20°C under nitrogen protection, kept warm for 15-30 minutes, and set aside. In a nitrogen environment, the high-temperature treatment of the desulfurized rubber powder increases the number of -C=O and -OH oxygen-containing groups on its surface, resulting in a large number of nano-scale pores on the surface, which can form a strong bond with the substrate.

[0010] Preferably, it is characterized in that, in step S3, the stirring process is accompanied by ultrasonic assisted dispersion, and the ultrasonic power is 800W and the frequency is 20kHz.

[0011] Preferably, it is characterized in that, in step S3, nano-mica powder is added in equal amounts in 2-5 times, and the interval between each addition is 3-8 minutes.

[0012] The present invention also provides a large proportion of waste asphalt, including the above-mentioned waste asphalt regeneration agent or the waste asphalt regeneration agent prepared by the above-mentioned preparation method.

[0013] Preferably, the mixture comprises, by mass, 70-90 parts of waste asphalt, 15-25 parts of limestone sand, 10.5-18 parts of the waste asphalt regeneration agent, 1-5 parts of new asphalt, and 0.05-0.15 parts of a long-chain aliphatic hydrocarbon warm-mixing agent.

[0014] The present invention also provides a method for preparing the above-mentioned large-scale waste asphalt, comprising the following steps: X1 Take solid waste asphalt, crush it, screen it, and take out fine material with particle size ≤4.75mm and coarse material with particle size 4.75-10mm; X2: Take the coarse material, heat it to 110-130℃, and set aside; take limestone sand, grind it to a particle size of ≤9.5mm, heat it to 190-210℃, and set aside; X3 Place the coarse material and fine material at 120-130°C and stir to mix them evenly to obtain a waste asphalt mixture; spray the waste asphalt regeneration agent on the surface of the waste asphalt mixture and stir; then add new asphalt and long-chain aliphatic hydrocarbon warm mix agent and stir again to obtain a large proportion of waste asphalt.

[0015] The technical solution of the present invention has the following beneficial effects: (1) The present invention uses epoxidized waste cooking oil and furfural refined oil as low surface tension carriers, which have deep penetration and the penetration depth in RAP can exceed 200 μm. Through diffusion, they enter the internal network of aged waste asphalt. Polycyclic aromatic hydrocarbons disassemble asphaltene aggregates through π-π conjugation, effectively destroying the oxidative cross-linking network, which can reduce the particle size and viscosity of waste asphalt. In addition, epoxidized waste cooking oil can be supplemented with long-chain ester colloid analogs containing polar end groups, which can increase the ratio of asphalt to colloid from the aged state and rebuild the sol-gel equilibrium system.

[0016] (2) The introduction of methyl carbamate into the base oil phase can act on the epoxidized waste cooking oil to form a highly polar oxazolidinone structure with excellent interfacial fusion properties, which can improve the adhesion between asphalt and siliceous aggregate. The asphalt after the above regeneration has a honeycomb structure, which significantly improves the nano-adhesion of asphalt. The -NHCOO- structure in methyl carbamate forms a hydrogen bond with the pyrrole nitrogen in the asphalt, which can enhance the cross-linking density and promote the adhesion between the various components in the regeneration agent and between the regeneration agent and the asphalt.

[0017] (3) Through the structural action of multiple raw material components, a multi-level reinforcement structure can be formed. In the above-mentioned oil phase system, SEBS forms a spatial network structure through swelling action, and through the modification action of desulfurized rubber powder and nano-mica powder, a spatial form with elasticity and strong network structure is formed, which can provide asphalt materials with stable low-temperature crack resistance and performance stability.

[0018] (4) The composite regenerated gel and the desulfurized rubber powder come into contact and bond with each other, so that the surface pores of the desulfurized rubber powder are fully filled, and the thiol groups on the surface of the desulfurized rubber powder react and bond with the double bonds of the SEBS modifier to form a -S-CH2-CH2- structure. The desulfurized rubber powder acts as a stress concentration point to induce silver streaks and absorb the energy of crack expansion, thereby increasing the bending strain energy of the asphalt material system at low temperatures, extending the ductility of a large proportion of waste asphalt, and improving the low-temperature crack resistance.

[0019] (5) The lamellar structure of nano-mica powder can extend the diffusion path of oxygen and other substances to achieve oxygen barrier effect, and prevent the aggregation of molecular chains. Combined with the capture of free radicals by epoxy groups, it can extend the aging induction period, that is, achieve long-term anti-aging effect.

[0020] Specific implementation content To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed; and where the manufacturers of the instruments, equipment, reagents, and raw materials used are not specified, they are all commercially available conventional products.

[0021] The present invention provides a waste asphalt regeneration agent and a large proportion of waste asphalt containing the same, as well as preparation methods of the waste asphalt regeneration agent and the large proportion of waste asphalt containing the same.

[0022] Calculated by mass fraction, the raw materials for the preparation of waste asphalt regeneration agent include: 45-55% epoxidized waste cooking oil, 15-20% furfural refined oil, 8-12% methyl carbamate, 3-5% nano mica powder, 10-15% desulfurized rubber powder, and 5-8% SEBS modifier.

[0023] The present invention also provides a method for preparing the above-mentioned waste asphalt regeneration agent, comprising the following steps: (1) Preprocessing Take epoxidized waste oil and heat it to 90±20°C to reduce the viscosity of the epoxidized waste oil from about 850mPa·s to 120mPa·s, thereby reducing the steric hindrance of the epoxy groups and improving the activity. In this state, furfural refined oil is added in amount and stirred at 500rpm for 10 minutes to form a homogeneous base oil phase. During the above-mentioned hot mixing process, the polar epoxy groups of the epoxidized waste oil and the large π bonds of the aromatic hydrocarbons of the furfural refined oil form a stable composite carrier through dipole-π interaction. The binding energy of the composite carrier can reach about 15kJ / mol, the surface tension is as low as about 28mN / m, and the contact angle is less than 10°, which can ensure that the composite carrier remains stable in subsequent reactions and composite material systems and avoids phase separation.

[0024] Separately, heat the desulfurized rubber powder to 120±20°C under nitrogen protection for 15-30 minutes to remove volatile impurities and set aside. In a nitrogen atmosphere, the high-temperature treatment at 120°C increases the number of -C=O and -OH oxygen-containing groups on the surface of the desulfurized rubber powder, creating a large number of nanopores on the surface, which can form a strong bond with the substrate.

[0025] (2) Compounding Take the homogeneous base oil phase, add methyl carbamate according to the amount, heat to 130±20℃, and stir at 1000±100rpm for 30min. The isocyanate group (-N=C=O) in the methyl carbamate attacks the epoxy group of the epoxidized waste oil at high temperature, which can cause a ring-opening reaction to form an oxazolidone structure, giving the regeneration agent a strong polar interface; then cool to 100±10℃, add the SEBS modifier while hot, and continue stirring at high speed until a uniform gel state is formed, that is, the rotational viscosity reaches 2000-3000mPa·s, to obtain a composite regenerated gel. The SEBS modifier swells in the furfural refined oil, and the styrene block forms physical cross-linking points to form a spatial network structure.

[0026] Among them, the SEBS modifier is a linear triblock copolymer with polystyrene as the terminal segment and ethylene-butene copolymer obtained by hydrogenating polybutadiene as the middle elastic block.

[0027] (3) Decentralized processing Take the composite regeneration gel maintained at a temperature of 100±10℃, add the desulfurized rubber powder obtained after pretreatment under nitrogen protection, stir at 200rpm for 20min, and disperse with ultrasound assistance, and the ultrasonic power is 800W, the frequency is 20kHz, the composite regeneration gel and the desulfurized rubber powder are in contact and combined with each other, so that the pores on the surface of the desulfurized rubber powder are fully filled, and the thiol group on the surface of the desulfurized rubber powder reacts with the double bond of the SEBS modifier to form a -S-CH2-CH2- structure, forming a highly stable elastic SEBS network structure. Improving the loss factor of the regeneration agent can extend the ductility of a large proportion of waste asphalt and improve its crack resistance; maintaining the above-mentioned ultrasonic and stirring state, evenly distribute 2-5 times to add nano mica powder with a particle size of D90≤5μm, each time with an interval of 3-8min, and continue stirring for 20min to complete the addition. The long-chain alkyl groups of the epoxidized waste oil are inserted into the mica layers, and the interlayer spacing is expanded, which can extend the diffusion path of oxygen and other substances, extend the oxidation induction period, and exert a long-term anti-aging effect. After cooling, a brown viscous liquid is obtained, and the density at 25°C is 1.02-1.05g / cm 3 , which is the waste asphalt regeneration agent of the present invention.

[0028] The waste asphalt regeneration agent proposed in the present invention realizes the synergistic effects of small molecule penetration, polar bonding and elasticity enhancement through the ternary system of "epoxidized waste oil + methyl carbamate + desulfurized rubber powder", and the combination of the regeneration agent composite system is stable and the effect is obvious.

[0029] Specifically, epoxidized waste cooking oil and furfural refined oil serve as low surface tension carriers with deep penetration, and the penetration depth in RAP can exceed 200μm; the addition of methyl carbamate can act on epoxidized waste cooking oil to form a highly polar oxazolidinone structure with excellent interfacial fusion properties, promoting the adhesion between the various components in the regeneration agent and between the regeneration agent and asphalt; in addition, SEBS forms a spatial network structure through swelling in the above-mentioned oil phase system, and through the modification of desulfurized rubber powder and nano-mica powder, forms a spatial form with elasticity and a strong network structure, which can provide asphalt materials with stable low-temperature crack resistance and performance stability; at the same time, the lamellar structure of nano-mica powder can bring oxygen barrier effect, combined with the capture of free radicals by epoxy groups, it can achieve long-term anti-aging effect.

[0030] When the waste asphalt regeneration agent of the present invention is used in a large proportion of waste asphalt, the preparation method of the large proportion of waste asphalt comprises the following steps: (1) Pretreatment of waste asphalt Solid waste asphalt is crushed until the particle size is ≤10mm, and sieved with a 4.75mm sieve to obtain fine RAP material ≤4.75mm and coarse RAP material 4.75-10mm.

[0031] (2) Compounding Take coarse RAP and heat it to 110-130°C, set aside. Grind limestone sand to a particle size of ≤9.5mm, heat it to 190-210°C, and set aside. Add the coarse RAP and fine RAP to a pot and stir at 120-130°C to obtain a waste asphalt mixture. Then, spray a waste asphalt regeneration agent (15-20wt% of the total mass of the waste asphalt mixture) and stir for 15-30 seconds. Finally, add new asphalt containing 3-8wt% of a long-chain aliphatic hydrocarbon warm mix agent and continue stirring for 30-60 seconds. Control the discharge temperature at 120-130°C to obtain a large proportion of waste asphalt.

[0032] Among them, by mass, waste asphalt is 70-90 parts, limestone sand is 15-25 parts, waste asphalt regeneration agent is 10.5-18 parts, new asphalt is 1-5 parts, and long-chain aliphatic hydrocarbon warm mix agent is 0.05-0.15 parts; among them, the mass ratio of coarse RAP and fine RAP in the waste asphalt is 4-5:3-4.

[0033] The regeneration agent proposed in this invention can regenerate and improve asphalt in large proportions of waste asphalt through the following processes: First, the epoxy waste oil and furfural refined oil in the regeneration agent diffuse into the internal network of aged waste asphalt. Polycyclic aromatic hydrocarbons disassemble asphaltene aggregates through π-π conjugation, effectively destroying the oxidative cross-linked network and reducing the particle size and viscosity of the waste asphalt. Second, the epoxy waste oil is supplemented with long-chain ester colloidal analogs containing polar end groups, which can increase the asphalt-to-colloid ratio from the aged state and restore the sol-gel equilibrium system. The -NHCOO- structure in the methyl carbamate forms hydrogen bonds with the pyrrolic nitrogen in the asphalt, enhancing the crosslink density. The nano-mica flakes, by intercalating between the asphalt layers, prevent molecular chain aggregation, thereby extending the aging induction period. Third, the polar components in the methyl carbamate increase the polar component of the asphalt's surface energy, improving the adhesion of the asphalt to siliceous aggregates. The asphalt after such regeneration has a honeycomb structure, which significantly improves the nanoscopic adhesion of the asphalt. Fourth, through the structural action of multiple raw material components, a multi-level reinforcement structure can be formed. SEBS swells in asphalt to form a three-dimensional physical cross-linked network, which significantly restores the elastic properties of waste asphalt. The desulfurized rubber powder acts as a stress concentration point to induce silver streaks and absorb crack expansion energy, thereby increasing the bending strain energy at low temperatures.

[0034] Example 1 (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 187.5g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0035] Take the base oil phase, add 141g of methyl carbamate, heat to 130℃, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100℃, and add 92g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100℃, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by ultrasonic assisted dispersion at 800W and 20kHz; under the above ultrasonic and stirring state, add nano mica powder with a particle size of ≤5μm in equal amounts of 30g / time three times, and wait 5min between each addition before the next addition. After the addition is completed, stir for 20min, cool, and obtain a regeneration agent.

[0036] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0037] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0038] Example 2 The difference between this embodiment and embodiment 1 is that the amount of regeneration agent in the asphalt material is different. The details are as follows: (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 187.5g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0039] Take the base oil phase, add 141g of methyl carbamate, heat to 130℃, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100℃, and add 92g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100℃, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by ultrasonic assisted dispersion at 800W and 20kHz; under the above ultrasonic and stirring state, add nano mica powder with a particle size of ≤5μm in equal amounts of 30g / time three times, and wait 5min between each addition before the next addition. After the addition is completed, stir for 20min, cool, and obtain a regeneration agent.

[0040] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0041] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 10g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0042] Example 3 The difference between this embodiment and embodiment 1 is that the amount of regeneration agent in the asphalt material is different. The details are as follows: (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 187.5g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0043] Take the base oil phase, add 141g of methyl carbamate, heat to 130℃, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100℃, and add 92g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100℃, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by ultrasonic assisted dispersion at 800W and 20kHz; under the above ultrasonic and stirring state, add nano mica powder with a particle size of ≤5μm in equal amounts of 30g / time three times, and wait 5min between each addition before the next addition. After the addition is completed, stir for 20min, cool, and obtain a regeneration agent.

[0044] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0045] Take the above-mentioned RAP coarse material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated RAP coarse material and RAP fine material to a feed pot and heat it to 125°C while stirring to form a waste asphalt mixture. Spray 18g of regeneration agent on the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Control the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0046] Example 4 The difference between this embodiment and embodiment 1 is that the raw materials used in the regeneration agent are different. The details are as follows: (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 152g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0047] Take the base oil phase, add 120g of methyl carbamate, heat to 130°C, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100°C, and add 75g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100°C, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by 800W, 20kHz ultrasonic assisted dispersion; under the above ultrasonic and stirring state, add nano mica powder with a particle size of ≤5μm in equal amounts of 25g / time in two times, and wait 5min between each addition before the next addition. After the addition is completed, stir continuously for 20min, cool, and obtain a regeneration agent.

[0048] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0049] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0050] Example 5 The difference between this embodiment and embodiment 1 is that the raw materials used in the regeneration agent are different. The details are as follows: (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 205g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0051] Take the base oil phase, add 155g of methyl carbamate, heat to 130°C, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100°C, and add 101g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100°C, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by ultrasonic assisted dispersion at 800W and 20kHz; under the above ultrasonic and stirring state, add nano mica powder with a particle size of ≤5μm in equal amounts of 18g / time in 5 times, and wait 5min between each addition before the next addition. After the addition is completed, stir continuously for 20min, cool, and obtain a regeneration agent.

[0052] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0053] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0054] Comparative Example 1 (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil, heat it evenly to about 90°C, add 225g of furfural refined oil, and stir at 500rpm for 10min to obtain a regeneration agent.

[0055] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0056] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0057] Comparative Example 2 (1) Preparation of regeneration agent Take 735g of epoxidized waste cooking oil and heat it evenly to approximately 90°C. Then add 225g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 50g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0058] Take the base oil phase, add 35g of methyl carbamate, heat to 130°C, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100°C, and add 20g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100°C, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by ultrasonic assisted dispersion at 800W and 20kHz; under the above ultrasonic and stirring state, add 10g of nano mica powder with a particle size of ≤5μm, and add the next addition after an interval of 5min after each addition. After the addition is completed, continue stirring for 20min, cool, and obtain a regeneration agent.

[0059] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0060] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0061] Comparative Example 3 (1) Preparation of regeneration agent Take 100g of epoxidized waste cooking oil and heat it evenly to about 90°C. Then add 50g of furfural refined oil and stir at 500rpm for 10 minutes to obtain the base oil phase, which is set aside. Separately, take 120g of desulfurized rubber powder and place it in a nitrogen atmosphere. Heat it to 120°C and keep it warm for 20 minutes. Cool it and set aside.

[0062] Take the base oil phase, add 100g of methyl carbamate, heat to 130°C, and stir at 1000rpm for 30min. After testing, the transmittance (550nm) of the material system reaches 90% or above; then cool to about 100°C, and add 85g of SEBS while hot at this temperature, and maintain high-speed stirring at 1000rpm until the material system forms a gel state. The rotational viscosity is measured to be in the range of 2000-3000mPa·s, thereby obtaining a composite regeneration gel; when the temperature of the composite regeneration gel is maintained in the range of 90-100°C, place it in a nitrogen protective atmosphere, add desulfurized rubber powder, and stir at 200rpm for 20min, during which time it is accompanied by 800W, 20kHz ultrasonic assisted dispersion; under the above ultrasonic and stirring state, add 80g of nano mica powder with a particle size of ≤5μm, and add the next addition after an interval of 5min after each addition. After the addition is completed, continue stirring for 20min, cool, and obtain a regeneration agent.

[0063] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0064] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0065] Comparative Example 4 (1) Preparation of regeneration agent Take 735g of epoxidized waste oil, 225g of furfural refined oil, 187.5g of desulfurized rubber powder, 141g of methyl carbamate, 92g of SEBS, and 90g of nano-mica powder, place them in a nitrogen protective atmosphere, heat to 100°C, and stir at 200rpm for 50min to obtain a regeneration agent.

[0066] (2) Preparation of asphalt containing a large proportion of waste asphalt Take enough solid waste asphalt, crush it, and sieve it through 10mm and 4.75mm sieves in turn to obtain RAP fine material ≤4.75mm and RAP coarse material 4.75-10mm. Take 44g RAP fine material and 36g RAP coarse material respectively for use.

[0067] Take the aforementioned coarse RAP material, heat it to 125°C, and set aside. Grind 20.5g of limestone sand to a particle size of ≤9.5mm, heat it to 195°C, and set aside. Add the heated coarse and fine RAP materials to a pot and heat to 125°C while stirring to form a waste asphalt mixture. Spray 14.3g of regeneration agent onto the surface of the waste asphalt mixture and stir for 20 seconds. Finally, add 0.1g of a long-chain aliphatic hydrocarbon warm mix agent and 3g of new asphalt. Maintain the temperature between 120-130°C, stir for another 45 seconds, and discharge the mixture to obtain an asphalt mixture containing a large proportion of waste asphalt.

[0068] Test example Samples: Raw materials and prepared asphalt materials in Examples 1-5 and Comparative Examples 1-4 The above samples were taken separately to measure the material properties of different samples, especially the performance characteristics such as fracture resistance under low temperature conditions. The specific measurement methods and results are summarized in Table 1 below: Table 1 Material performance test results of different samples

[0069] Among them, the creep stiffness of asphalt is a key indicator of its low-temperature crack resistance. Creep stiffness refers to the ratio of applied stress to resulting strain at a specific test time and temperature, reflecting the asphalt's ability to resist deformation at that low temperature. Asphalt becomes harder and more brittle as the temperature decreases. If the asphalt is too hard, the measured creep stiffness will be too high. When the creep stiffness of asphalt at a certain temperature exceeds a critical value, the risk of low-temperature cracking of the asphalt pavement at that temperature becomes very high. Therefore, the low-temperature crack resistance of asphalt can be compared based on the principle that lower creep stiffness indicates higher low-temperature crack resistance.

[0070] The above-mentioned test and measurement results indicate that the asphalt materials of the above-mentioned samples all contain significantly more than 50wt% waste asphalt. The asphalt materials of Examples 1 to 5 exhibit significantly lower low-temperature creep stiffness than the asphalt materials of Comparative Examples 1 to 4, and exhibit superior performance in terms of penetration, ductility, rutting factor, and adhesion work. This demonstrates that the waste asphalt regeneration agent and the high-proportion waste asphalt containing it proposed by the present invention can address the problem of poor low-temperature crack resistance in asphalt mixtures with excessively high waste asphalt content, which exists in existing high-proportion waste asphalt solutions. Specifically, by promptly incorporating a large amount of waste asphalt, the resulting asphalt mixture can also exhibit excellent low-temperature crack resistance and performance stability.

[0071] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A waste asphalt regeneration agent, characterized in that: The raw materials for preparing the waste asphalt regeneration agent include the following components by mass fraction: 45-55% epoxidized waste cooking oil, 15-20% furfural refined oil, 8-12% methyl carbamate, 3-5% nano mica powder, 10-15% desulfurized rubber powder, and 5-8% SEBS modifier; Furthermore, the waste asphalt regeneration agent has a three-dimensional network structure bonded by polarity.

2. The waste asphalt regeneration agent according to claim 1, characterized in that: The particle size of nano mica powder is ≤5μm.

3. A method for preparing the waste asphalt regeneration agent according to claim 1, characterized in that: The steps include: S1: Take epoxidized waste cooking oil, heat it to 90±20℃, then add furfural refined oil and stir to form a base oil phase; S2: Add methyl carbamate to the base oil phase, heat to 130±20°C, and stir; then cool to 100±10°C, add SEBS modifier, and stir to obtain a composite regenerated gel; S3: The composite regeneration gel is kept warm at 100±10° C., desulfurized rubber powder is added, and the mixture is stirred. Nano-mica powder is also added, and the mixture is stirred again to obtain the waste asphalt regeneration agent.

4. The method for preparing the waste asphalt regeneration agent according to claim 3, characterized in that: In step S2, after adding the desulfurized rubber powder and after adding the nano-mica powder, the stirring speed is 1000±100 rpm and the stirring time is 30-60 min.

5. The method for preparing the waste asphalt regeneration agent according to claim 3, characterized in that: In step S3, the desulfurized rubber powder is pretreated as follows before being added: Take the desulfurized rubber powder, heat it to 120±20℃ under nitrogen protection, keep it warm for 15-30 minutes, and set aside.

6. The method for preparing the waste asphalt regeneration agent according to claim 3, characterized in that: In step S3, the stirring process is accompanied by ultrasonic-assisted dispersion, and the ultrasonic power is 800 W and the frequency is 20 kHz.

7. The method for preparing the waste asphalt regeneration agent according to claim 3, characterized in that: In step S3, nano-mica powder is added in equal amounts in 2-5 times, with an interval of 3-8 minutes between each addition.

8. A large proportion of waste asphalt, characterized in that: include: The waste asphalt regeneration agent according to claim 1 or 2, or the waste asphalt regeneration agent prepared by the preparation method according to any one of claims 3 to 7.

9. The large proportion of waste asphalt according to claim 8, characterized in that: Calculated by mass, it includes 70-90 parts of waste asphalt, 15-25 parts of limestone sand, 10.5-18 parts of the waste asphalt regeneration agent, 1-5 parts of new asphalt, and 0.05-0.15 parts of a long-chain aliphatic hydrocarbon warm-mix agent.

10. A method for preparing a large proportion of waste asphalt according to claim 8, characterized in that: The steps include: X1 Take solid waste asphalt, crush it, screen it, and take out fine material with particle size ≤4.75mm and coarse material with particle size 4.75-10mm; X2: Take the coarse material, heat it to 110-130℃, and set aside; take limestone sand, grind it to a particle size of ≤9.5mm, heat it to 190-210℃, and set aside; X3 Place the coarse material and fine material at 120-130°C and stir to mix them evenly to obtain a waste asphalt mixture; spray the waste asphalt regeneration agent on the surface of the waste asphalt mixture and stir; then add new asphalt and long-chain aliphatic hydrocarbon warm mix agent and stir again to obtain a large proportion of waste asphalt.

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