High-stability asphalt cold patch material prepared from oil-stone separation recycled material and preparation method of high-stability asphalt cold patch material

Abstract

The invention is suitable for the technical field of resource utilization of road engineering materials and solid wastes, and provides a high-stability asphalt cold patch material prepared from an oil-stone separation recycled material and a preparation method of the high-stability asphalt cold patch material. The cold patch material is prepared from the following components: an oilstone separation recycled material, an interfacial activator, self-repairing type regenerated reinforced slurry, a gradient deblocking type polyurethane-graphene composite skeleton component and mineral powder, according to the invention, the residual asphalt film is converted into an active coupling layer through synergistic treatment of the interfacial activator and microwaves; a Diels-Alder dynamic covalent bond is introduced to endow the regenerated enhanced slurry with a self-repairing function, and the repairing mechanism is based on reversible dissociation-recombination of a DA bond; by compounding closed polyurethane and carboxylated graphene at two deblocking temperatures of low temperature and high temperature, time sequence controllable release of strength is realized. The product is stable in storage, convenient to construct and suitable for long-acting repair of road pits and slots, and high-value utilization of oil-stone separation recycled materials is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of road engineering materials and solid waste resource utilization, and particularly relates to a high-stability asphalt cold patch material prepared from oil-stone separation and recovery materials and a preparation method thereof. BACKGROUND

[0002] The asphalt pavement cold patch material is widely used in the daily maintenance of road pits and grooves due to the advantages of convenient storage, quick construction and no restriction by low-temperature seasons; however, there are two technical bottlenecks in the use of waste asphalt mixture (RAP) in the existing cold patch material: Weak interface bonding: a small amount of aged asphalt film (usually 0.1-0.3mm thick) is left on the surface of the stone after oil-stone separation, the residual film layer has low polarity and poor activity, and it is difficult for the traditional cold patch material binder to form a firm chemical bond therewith, resulting in easy interface peeling and poor water stability of the cold patch material. The technical prejudice widely existing in the field is that the residual aged asphalt film is a weak interface defect and needs to be removed by water washing or high-temperature incineration. However, these methods have high energy consumption and are easy to damage the aggregate.

[0003] Strength and storage contradiction: the cold patch material needs to be stored for a long time without hardening at room temperature, and also needs to quickly form strength after construction, and has insufficient ability to resist micro-crack propagation in later use. The existing technology usually adds a large amount of diluent to ensure the fluidity during the storage period, but sacrifices the early strength and durability; or increases the resin content to improve the strength, but causes the storage to be easily hardened.

[0004] Therefore, it is of important engineering value to develop a cold patch material which can efficiently utilize oil-stone separation and recovery materials, has excellent interface bonding, controllable strength and self-repairing function. SUMMARY

[0005] The application provides a high-stability asphalt cold patch material prepared from oil-stone separation and recovery materials and a preparation method thereof, and aims to solve the technical problems of weak interface bonding, no self-repairing function and contradiction between strength and storage stability of the cold patch material prepared from oil-stone separation and recovery materials in the prior art.

[0006] The application is implemented in the following manner: a high-stability asphalt cold patch material prepared from oil-stone separation and recovery materials is prepared from the following raw materials by weight: oil-stone separation and recovery materials 75-85 parts; an interface activator 0.3-0.8 parts; a self-repairing type regenerated reinforcing paste 10-15 parts; a gradient unblocking type polyurethane-graphene composite skeleton component 6-10 parts; and mineral powder 3-6 parts. The interface activator is epoxy chloropropane modified tall oil, which contains epoxy groups and carboxyl groups at the same time, and can form chemical bonds with the polar groups in the residual asphalt and the surface of the stone; The self-repairing regeneration reinforced paste is made of waste asphalt separated and recovered from oil and stone, furan modified vegetable oil polyol and bismaleimide through ester exchange and Diels-Alder reaction, and contains reversible dynamic covalent bonds. The gradient deblocking type polyurethane-graphene composite framework component contains at least two types of blocked polyurethane prepolymer with different deblocking temperatures and edge carboxylated graphene.

[0007] Preferably, the oil and stone separated and recovered material used is coarse and fine aggregate obtained after oil and stone separation of waste asphalt mixture, and the old asphalt content is required to be 4.0%-5.5%, the gradation is 1:1-1.5:1 of the mass ratio of 0-5mm fine aggregate to 5-10mm coarse aggregate, and the surface residual aging asphalt film thickness is 0.1-0.3mm.

[0008] Preferably, the interface activator is prepared by reacting tall oil with epichlorohydrin at a molar ratio of 1:0.8-1.2 under the catalysis of tetrabutylammonium bromide with a mass fraction of 0.5%-1% of the tall oil at 80-90℃ for 3-4h, and then removing the excess epichlorohydrin by vacuum distillation, and the epoxy value of the interface activator is 0.2-0.4mol / 100g (GB / T 1677-2008), and the acid value is 30-50mgKOH / g (GB / T 1668-2008).

[0009] Preferably, in the self-repairing regeneration reinforced paste, the mass ratio of waste asphalt (separated and recovered from oil and stone, with a penetration of 15-30dmm) to furan modified vegetable oil polyol is 60:40-80:20, and the molar ratio of furan groups to maleimide groups in bismaleimide is 1:0.8-1.2; the Diels-Alder reaction temperature is 100-120℃, and the reaction time is 0.5-1.5h.

[0010] The realization of the self-repairing function is based on the reversible characteristics of the low-energy-barrier furan-bismaleimide Diels-Alder (DA) dynamic covalent bond. When the cold patch material generates micro-cracks due to load or temperature shrinkage, under the combined action of natural sunlight irradiation (especially the ultraviolet band) and the friction heat generated by vehicle rolling (which can make the local temperature rise to 40-60℃), the DA bond at the crack reversibly dissociates and recombines, realizing the chemical rebonding of the crack interface, thereby restoring the material strength and integrity.

[0011] Preferably, the furan modified vegetable oil polyol is prepared by reacting epoxidized soybean oil with furfurylamine at a molar ratio of epoxy group to amine group of 1:1 at 60-80℃ for 2-4h, and the hydroxyl value is 160-200mgKOH / g (GB / T 12008.3-2009); and the bismaleimide is N,N'-4,4'-diphenylmethane bismaleimide or N,N'-m-phenylene bismaleimide.

[0012] Preferably, the internal composition of the gradient-desealing polyurethane-graphene composite framework component is as follows: 8-12 parts of low-temperature unblocking polyurethane prepolymer, with an unblocking temperature of 70-90℃, are produced by reacting polyether polyol N220 (hydroxyl value 56mgKOH / g) with MDI to generate terminal NCO prepolymer (NCO mass content 3%~5%), and then blocked with methyl ethyl ketone oxime; 5-8 parts of high-temperature deblocking polyurethane prepolymer, with a deblocking temperature of 110-130℃, are used. The prepolymer is also sealed with caprolactam. One to two parts of edge-carboxylated graphene, with a carboxyl content of 5-10 mmol / g; 70-80 parts of environmentally friendly solvent oil; 0.5-1 part of dispersant stabilizer; The edge-carboxylated graphene is obtained by ultrasonically exfoliating graphene oxide, mixing it with chloroacetic acid at a mass ratio of 1:5 to 1:8, reacting it under alkaline conditions (pH=9 to 11) at 60 to 70°C for 2 to 3 hours, filtering, washing, and drying, with a carboxyl content of 5-10 mmol / g (acid-base titration method); the dispersant stabilizer is polyhydroxy fatty acid ester; the environmentally friendly solvent oil is a mixture of 120# solvent oil and vegetable oil methyl ester at a mass ratio of 1:1.

[0013] Low-temperature polyurethane prepolymers preferentially de-encapsulate during the initial stage of construction and compaction (approximately 70-90℃ due to frictional heat), releasing isocyanate groups that react with hydroxyl groups in the regenerated slurry to form a polyurethane covalent network, imparting early strength. High-temperature polyurethane prepolymers gradually de-encapsulate during summer high temperatures or long-term service (110-130℃), continuously enhancing crosslinking density and achieving later strength growth. Simultaneously, edge-carboxylated graphene, on the one hand, prevents crack propagation through its nanosheet structure, and on the other hand, its surface carboxyl groups can form hydrogen bonds or ester bonds with hydroxyl groups in the regenerated slurry and furan groups in the DA network, becoming a "molecular bridge" connecting the dynamic and static networks. Bio-based PHA can simultaneously disperse graphene and stabilize polyurethane prepolymers, preventing sedimentation.

[0014] Preferably, the mineral powder is limestone mineral powder, and its fineness meets the requirements of road engineering.

[0015] The present invention also provides a method for preparing the above-mentioned cold patching asphalt, characterized by comprising the following steps: (1) Surface activation treatment of recycled material: The oil-stone separation recycled material is fed into a continuous microwave drum activation chamber, and an interface activator (accounting for 0.3-0.8% of the recycled material mass) is sprayed through a nozzle. The material is treated for 3-8 minutes under microwave power density of 1.5-3.0kW / kg, and the material temperature is controlled at 100-130℃ to obtain surface activated recycled material. The residual asphalt film is selectively heated by microwave to soften it and react with the interface activator. At the same time, the carboxyl groups in the interface activator chelate with the calcium ions on the stone surface, transforming the inert asphalt film into a reactive flexible coupling layer. This coupling layer forms a strong anchor by forming ionic bonds with the calcium ions on the stone surface through the carboxyl groups. On the other hand, it forms a chemical bond interface by reacting with the hydroxyl and carboxyl groups in the subsequently added self-healing regenerated slurry through the epoxy groups. This provides a solid interface foundation for the entire system. (2) Preparation of self-healing regenerated reinforced slurry: The waste asphalt recovered from oilstone separation is heated to 120-140℃, furan-modified vegetable oil polyol and organotin catalyst are added, and the transesterification reaction is carried out at 160-180℃ for 1.5-3 hours. After natural cooling to 100-120℃, bismaleimide is added and the reaction is stirred for 0.5-1.5 hours to form a regenerated reinforced slurry containing Diels-Alder dynamic covalent bonds. After forming chemical bonds with the activated surface in the pre-coating stage, it can achieve self-healing of microcracks through reversible dissociation-reorganization of DA bonds at the service temperature (40-80℃). More importantly, the abundant hydroxyl and furan groups in the regenerated slurry provide sufficient reaction sites for subsequent chemical cross-linking with the gradient unsealing skeleton, realizing the fusion of "dynamic" and "static" networks. (3) Preparation of gradient unsealing polyurethane-graphene composite skeleton components: Low-temperature unsealing polyurethane prepolymer, high-temperature unsealing polyurethane prepolymer, edge carboxyl graphene, and dispersant stabilizer are added to environmentally friendly solvent oil, stirred and dissolved at 50-70℃ for 1-2 hours, and ultrasonically dispersed for 20-40 minutes to obtain composite skeleton components. (4) Stepwise agglomeration preparation of cold patching material: a. Pre-coating treatment: Add the surface-activated recycled material (temperature 100-130℃) into the mixing tank, add the regenerated reinforcing slurry preheated to 80-100℃, control the temperature difference between the regenerated reinforcing slurry and the surface-activated recycled material to ≤30℃, and mix for 30-60 seconds; during this stage, the furan groups in the regenerated reinforcing slurry chemically bond with the active sites on the activated layer to form a strong base coating. b. Activation: The mixed material is left to stand and age in a closed mixing tank for 5-10 minutes, with the aging temperature controlled at 60-80℃; during this process, the DA bonds in the regenerated reinforced slurry are partially reorganized to form a preliminary network, and at the same time, it further penetrates and reacts with the surface of the aggregate. c. Secondary film formation: Add the composite skeleton component and mineral powder to the mixing tank and continue mixing for 60-90 seconds until uniform; during the mixing process, the closed polyurethane prepolymer in the composite skeleton component has not yet been unsealed, and the solvent oil plays a diluting role to ensure uniform mixing; the graphene is uniformly dispersed. (5) Discharge the material and allow it to cool naturally to room temperature. Then seal it with moisture-proof packaging (such as a woven bag lined with a plastic bag) to obtain high-stability asphalt cold patching material.

[0016] Preferably, the organotin catalyst in step (2) is dibutyltin dilaurate, and the amount used is 0.1%-0.3% of the total mass of waste asphalt and furan-modified vegetable oil polyol.

[0017] Preferably, the ultrasonic dispersion frequency in step (3) is 20-40kHz and the power density is 0.3-0.5W / mL.

[0018] Preferably, the mixing tank in step (4) is a twin-shaft forced mixer with heat preservation function, which is kept sealed during the mixing process.

[0019] Compared with the prior art, the embodiments of this application have the following main advantages: The high-stability asphalt cold patch material prepared from oil-stone separation and recycling materials provided by this invention solves the problems of weak interfacial adhesion, lack of self-healing, and contradiction between strength and storage in existing recycled cold patch materials through the synergistic design of interface activation, dynamic self-healing, and gradient unsealing enhancement. It achieves a high utilization rate of over 75% of oil-stone separation and recycling materials. The product has excellent interfacial adhesion, storage stability, high and low temperature performance, and self-healing properties. It is suitable for long-term repair of potholes on heavy-duty roads and in low-temperature areas, and its service life is improved compared with existing cold patch materials. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for preparing asphalt cold patching material provided by the present invention.

[0021] Figure 2 This is a bar chart comparing the 24-hour Marshall stability and the peeling rate by boiling water for each sample. Detailed Implementation

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] Example 1 1. Raw material preparation (1) Preparation of interfacial activators: Take 100g of tall oil (acid value 165 mgKOH / g), add 35g of epichlorohydrin (molar ratio approximately 1:0.95), and then add 0.8g of tetrabutylammonium bromide as a catalyst. Stir the reaction at 85℃ for 3.5 hours. After the reaction is complete, remove excess epichlorohydrin by vacuum distillation to obtain the interface activator; its epoxy value is 0.31mol / 100g (GB / T 1677-2008), and its acid value is 41mgKOH / g (GB / T 1668-2008).

[0025] (2) Preparation of furan-modified vegetable oil polyols: Take 100g of epoxidized soybean oil (epoxidation value 6.2%), add 28g of furfurylamine (the molar ratio of epoxidized group to amino group is about 1:1), stir and react at 70℃ for 3 hours to obtain furan-modified epoxidized soybean oil; the hydroxyl value was tested to be 175mgKOH / g (GB / T12008.3-2009).

[0026] (3) Preparation of self-healing regenerated reinforced pulp: Take 70g of waste asphalt (penetration 25dmm) recovered from oilstone separation, add 30g of furan-modified epoxidized soybean oil obtained in step (2), and then add 0.2g of dibutyltin dilaurate (accounting for 0.2% of the total mass of the two), heat to 170℃, and perform transesterification reaction for 2 hours; then cool naturally to 110℃, add 12.5g of N,N'-4,4'-diphenylmethane bismaleimide (calculated according to the molar ratio of furan group to maleimide group 1:1), stir and react for 1 hour to obtain a self-healing regenerated reinforced slurry containing Diels-Alder dynamic covalent bonds; take 12 parts of this slurry (i.e. 12g, calculated as 1g per part) for cold patching preparation.

[0027] (4) Preparation of edge-carboxylated graphene: 10 g of graphene oxide (GO, 1-5 layers) was added to 500 mL of deionized water and ultrasonically exfoliated for 30 minutes (frequency 30 kHz, power 300 W). Then, 60 g of chloroacetic acid was added (GO:chloroacetic acid mass ratio = 1:6), the pH was adjusted to 10 with NaOH, and the temperature was raised to 65 °C for 2.5 hours. After the reaction, the mixture was filtered, washed with deionized water until neutral, and vacuum dried at 60 °C for 24 hours to obtain edge-carboxylated graphene. The carboxyl content was determined to be 8.2 mmol / g by acid-base titration.

[0028] (5) Preparation of gradient-desealed polyurethane-graphene composite framework components: ① Low-temperature unblocking polyurethane prepolymer: Take 100g of polyether polyol N220 (hydroxyl value 56 mgKOH / g) and react it with 35g of MDI at 80℃ for 2 hours to generate an NCO-terminated prepolymer (NCO content 4.2%). Cool down to 50℃, add 12g of methyl ethyl ketone oxime, and react for 1 hour to obtain a blocked polyurethane prepolymer with an unblocking temperature of 80℃.

[0029] ② High-temperature deblocking polyurethane prepolymer: Take 100g of NCO-terminated prepolymer, add 18g of caprolactam, and react at 80℃ for 2 hours to obtain a closed polyurethane prepolymer with a deblocking temperature of 120℃.

[0030] ③ Composite skeleton component preparation: Take 10g of the low-temperature unsealing polyurethane prepolymer obtained in step ①, 6g of the high-temperature unsealing polyurethane prepolymer obtained in step ②, 1.5g of the edge carboxyl graphene obtained in step (4), 0.8g of polyhydroxy fatty acid ester (PHA, dispersion stabilizer), add 81.7g of environmentally friendly solvent oil (120# solvent oil and vegetable oil methyl ester mixed at a mass ratio of 1:1), stir and dissolve at 60℃ for 1.5 hours, and then ultrasonically disperse for 30 minutes (frequency 30kHz, power density 0.4 W / mL) to obtain a uniformly dispersed gradient unsealing polyurethane-graphene composite skeleton component; take 8 parts (i.e. 8g) of this mixture for cold patch preparation.

[0031] (6) Oil-stone separation and recovery materials: The coarse and fine aggregates obtained after separating waste asphalt mixture from asphalt and stone contain 4.8% old asphalt, and the mass ratio of 0-5mm fine aggregate to 5-10mm coarse aggregate is 45:35 (i.e., 45 parts fine aggregate and 35 parts coarse aggregate). The thickness of the residual aged asphalt film on the surface is about 0.2mm. A total of 80 parts are used for the preparation of cold patching material.

[0032] (7) Mineral powder: Take limestone ore powder with a fineness of ≥80% passing through a 0.075mm sieve, and take 5 portions for cold patching material preparation.

[0033] 2. Preparation of cold patching material (1) Surface activation treatment of recycled materials: 80 parts of the oilstone separation and recovery material from step 1 (6) were fed into a continuous microwave drum activation chamber, and 0.6 parts of the interface activator obtained in step 1 (1) were sprayed through a nozzle; the material was treated for 6 minutes under microwave power density of 2.2 kW / kg, and the material temperature was controlled at 115℃ to obtain surface activated recovery material.

[0034] (2) Stepwise polymerization preparation: ① Pre-coating treatment: The surface-activated recycled material (temperature 115℃) obtained in step (1) is put into a twin-shaft forced mixing tank with heat preservation function, and 12 parts of the self-healing regenerated reinforcing slurry prepared in step 1 (3) (preheated to 90℃) are added. The temperature difference between the two is 25℃, and they are mixed for 45 seconds.

[0035] ②Activation: After mixing, seal the mixing tank and let it stand for 8 minutes to age, keeping the material temperature at around 70℃.

[0036] ③ Secondary film formation: Add 8 parts of the gradient unsealing polyurethane-graphene composite skeleton component obtained in step 1 (5) and 5 parts of the mineral powder in step 1 (7) to the mixing tank, and continue to mix for 75 seconds until uniform.

[0037] (3) Discharge, cooling, and packaging: The mixed cold patch material is discharged and allowed to cool naturally to room temperature. It is then sealed in a woven bag lined with a plastic bag to obtain the finished product.

[0038] Example 2 1. Raw material preparation (1) Preparation of interfacial activators: Take 100g of tall oil, add 30g of epichlorohydrin (molar ratio approximately 1:0.82) and 0.6g of tetrabutylammonium bromide, react at 80℃ for 4 hours, and obtain the interface activator after vacuum distillation; epoxy value 0.22mol / 100g, acid value 32mgKOH / g.

[0039] (2) Preparation of furan-modified vegetable oil polyols: Take 100g of epoxidized soybean oil, add 26g of furfurylamine, and react at 60℃ for 4 hours to obtain furan-modified oil; hydroxyl value 162mgKOH / g.

[0040] (3) Preparation of self-healing regenerated reinforced pulp: Take 60g of waste asphalt (penetration 28dmm), add 40g of furan-modified oil obtained in step (2), and 0.1g of dibutyltin dilaurate (accounting for 0.1%), and perform transesterification at 160℃ for 3 hours; cool naturally to 100℃, add 10.2g of N,N'-m-phenylenebismaleimide (furan:maleimide molar ratio 1:0.8), and react for 0.5 hours to obtain regenerated reinforced slurry; take 10 parts of this slurry for cold patching.

[0041] (4) Preparation of edge-carboxylated graphene: Take 10g of graphene oxide, ultrasonically exfoliate it, add 50g of chloroacetic acid (mass ratio 1:5), pH=9, react at 60℃ for 3 hours, wash and dry to obtain the product; carboxyl content 5.2 mmol / g.

[0042] (5) Preparation of gradient-desealed polyurethane-graphene composite framework components: ① Low-temperature unsealing type: Prepared according to the method of Example 1, with the NCO content adjusted to 3.5% and the unsealing temperature at 75°C.

[0043] ② High-temperature unsealing type: Prepared according to the method of Example 1, unsealing temperature is 115℃.

[0044] ③ Composite framework composition preparation: Take 8g of low temperature type, 5g of high temperature type, 1g of edge carboxyl graphene, 0.5g of PHA, and 70g of environmentally friendly solvent oil, stir at 50℃ for 2 hours, and ultrasonically disperse for 20 minutes (20kHz, 0.3 W / mL); take 6 parts of this mixture for cold replenishment.

[0045] (6) Oil-stone separation and recovery materials: The old asphalt content is 4.2%, with 35 parts of 0-5mm fine aggregate and 40 parts of 5-10mm coarse aggregate, totaling 75 parts.

[0046] (7) Mineral powder: 3 parts.

[0047] 2. Preparation of cold patching material (1) Surface activation treatment of recycled materials: 75 parts of the recycled material were fed into a microwave drum, 0.3 parts of an interface activator were sprayed on, the microwave power density was 1.5 kW / kg, the treatment lasted for 8 minutes, and the material temperature was 100℃ to obtain activated recycled material.

[0048] (2) Stepwise polymerization preparation: ① Pre-coating treatment: Add 10 parts of regenerated reinforced slurry preheated to 80℃ (temperature difference 20℃) to activated recycled material (100℃) and mix for 30 seconds.

[0049] ②Activation: Aging in a sealed environment for 5 minutes at 60℃.

[0050] ③ Secondary film formation: Add 6 parts of the composite skeleton component and 3 parts of mineral powder, and mix for 60 seconds.

[0051] (3) Discharge, cooling and packaging: Same as in Example 1.

[0052] Example 3 1. Raw material preparation (1) Preparation of interfacial activators: Take 100g of tall oil, add 40g of epichlorohydrin (molar ratio about 1:1.1) and 1.0g of tetrabutylammonium bromide, and react at 90℃ for 3 hours to obtain an interface activator; epoxy value 0.38mol / 100g, acid value 48mgKOH / g.

[0053] (2) Preparation of furan-modified vegetable oil polyols: Take 100g of epoxidized soybean oil, add 30g of furfurylamine, and react at 80℃ for 2 hours to obtain furan-modified oil; hydroxyl value 198mgKOH / g.

[0054] (3) Preparation of self-healing regenerated reinforced pulp: Take 80g of waste asphalt (penetration 18dmm), add 20g of furan-modified oil obtained in step (2), and 0.3g of dibutyltin dilaurate (accounting for 0.3%), and perform transesterification at 180℃ for 1.5 hours; cool naturally to 120℃, add 16.8g of N,N'-4,4'-diphenylmethane bismaleimide (furan:maleimide molar ratio 1:1.2), and react for 1.5 hours to obtain regenerated reinforced slurry; take 15 parts of this slurry for cold patching.

[0055] (4) Preparation of edge-carboxylated graphene: Take 10g of graphene oxide, ultrasonically exfoliate it, add 80g of chloroacetic acid (mass ratio 1:8), pH=11, react at 70℃ for 2 hours, wash and dry to obtain the product; carboxyl content 9.8 mmol / g.

[0056] (5) Preparation of gradient-desealed polyurethane-graphene composite framework components: ①Low-temperature unsealing type: NCO content 4.8%, unsealing temperature 88℃.

[0057] ②High-temperature unsealing type: unsealing temperature 128℃.

[0058] ③ Composite framework composition preparation: Take 12g of low temperature type, 8g of high temperature type, 2g of edge carboxyl graphene, 1g of PHA, and 80g of environmentally friendly solvent oil, stir at 70℃ for 1 hour, and ultrasonically disperse for 40 minutes (40kHz, 0.5 W / mL); take 10 parts of this mixture for cold replenishment.

[0059] (6) Oil-stone separation and recovery materials: The old asphalt content is 5.3%, with 50 parts of 0-5mm fine aggregate and 35 parts of 5-10mm coarse aggregate, for a total of 85 parts.

[0060] (7) Mineral powder: 6 parts.

[0061] 2. Preparation of cold patching material (1) Surface activation treatment of recycled materials: 85 parts of the recycled material were fed into a microwave drum, 0.8 parts of an interface activator were sprayed on, the microwave power density was 3.0 kW / kg, the treatment lasted for 3 minutes, and the material temperature was 130℃, to obtain activated recycled material.

[0062] (2) Stepwise polymerization preparation: ① Pre-coating treatment: Add 15 parts of regenerated reinforced slurry preheated to 100℃ (temperature difference 30℃) to activated recycled material (130℃) and mix for 60 seconds.

[0063] ②Activation: Aging in a sealed environment for 10 minutes at 80℃.

[0064] ③ Secondary film formation: Add 10 parts of the composite skeleton component and 6 parts of mineral powder, and mix for 90 seconds.

[0065] (3) Discharge, cooling and packaging: Same as in Example 1.

[0066] Example 4 1. Raw material preparation (1) Preparation of interfacial activators: Take 100g of tall oil, add 36g of epichlorohydrin and 0.7g of tetrabutylammonium bromide, and react at 82℃ for 3.8 hours to obtain an interface activator; epoxy value 0.28mol / 100g, acid value 38mgKOH / g.

[0067] (2) Preparation of furan-modified vegetable oil polyols: Take 100g of epoxidized soybean oil, add 27g of furfurylamine, and react at 65℃ for 3.5 hours to obtain furan-modified oil. Hydroxyl value: 182mgKOH / g.

[0068] (3) Preparation of self-healing regenerated reinforced pulp: Take 75g of waste asphalt (penetration 22dmm), add 25g of furan-modified oil obtained in step (2), and 0.25g of dibutyltin dilaurate (accounting for 0.25%), and perform transesterification at 165℃ for 2.5 hours; cool naturally to 105℃, add 14.5g of N,N'-4,4'-diphenylmethane bismaleimide (furan:maleimide molar ratio 1:1), and react for 1.2 hours to obtain regenerated reinforced slurry; take 13 parts of this slurry for cold patching.

[0069] (4) Preparation of edge-carboxylated graphene: Take 10g of graphene oxide, ultrasonically exfoliate it, then add 70g of chloroacetic acid (mass ratio 1:7), pH=10.5, react at 68℃ for 2.2 hours, wash and dry to obtain the product. Carboxyl content 7.5mmol / g.

[0070] (5) Preparation of gradient-desealed polyurethane-graphene composite framework components: ①Low-temperature unsealing type: NCO content 4.0%, unsealing temperature 82℃.

[0071] ②High-temperature unsealing type: unsealing temperature 122℃.

[0072] ③ Composite framework composition preparation: Take 11g of low temperature type, 7g of high temperature type, 1.8g of edge carboxyl graphene, 0.8g of PHA, and 75g of environmentally friendly solvent oil, stir at 65℃ for 1.5 hours, and ultrasonically disperse for 35 minutes (35kHz, 0.45 W / mL); take 9 parts of this mixture for cold replenishment.

[0073] (6) Oil-stone separation and recovery materials: The old asphalt content is 5.0%, with 42 parts of 0-5mm fine aggregate and 36 parts of 5-10mm coarse aggregate, for a total of 78 parts.

[0074] (7) Mineral powder: 4 parts.

[0075] 2. Preparation of cold patching material (1) Surface activation treatment of recycled materials: 78 parts of the recycled material were fed into a microwave drum, 0.5 parts of an interface activator were sprayed on, the microwave power density was 2.5 kW / kg, and the treatment lasted for 5 minutes at a material temperature of 120℃ to obtain activated recycled material.

[0076] (2) Stepwise polymerization preparation: ① Pre-coating treatment: Add 13 parts of regenerated reinforced slurry preheated to 95℃ (temperature difference 25℃) to activated recycled material (120℃) and mix for 50 seconds.

[0077] ②Activation: Aging in a sealed environment for 7 minutes at 72℃.

[0078] ③ Secondary film formation: Add 9 parts of composite skeleton component and 4 parts of mineral powder, and mix for 80 seconds.

[0079] (3) Discharge, cooling and packaging: Same as in Example 1.

[0080] Comparative Example 0: 1. Raw material preparation: Ordinary recycled reinforced slurry: Take 70g of waste asphalt, add 30g of ordinary epoxidized soybean oil (unmodified with furan) and 0.2g of dibutyltin dilaurate, and perform transesterification at 170℃ for 2 hours to obtain ordinary recycled slurry; take 12 parts for cold patching.

[0081] Ordinary polyurethane components: Take 15g of ordinary polyurethane prepolymer (unclosed), add 85g of environmentally friendly solvent oil, stir to dissolve, without adding graphene; take 8 parts for cold patching material.

[0082] The remaining raw materials are the same as in Example 1: 80 parts of oilstone separation and recovery material and 5 parts of mineral powder, without the addition of interface activator.

[0083] 2. Preparation process: The conventional one-time mixing method is adopted. The recycled material, ordinary recycled slurry, ordinary polyurethane components and mineral powder are put into the mixing tank at one time, mixed for 120 seconds, and then discharged.

[0084] Comparative Example 1 (without surface activation): It is basically the same as Example 1, except that no interface activator is added in step 2 (1), and the oilstone separation and recovery material is directly mixed in the subsequent process.

[0085] Comparative Example 2 (without DA self-healing): It is basically the same as Example 1, except that bismaleimide is not added when preparing the regenerated reinforced slurry in step 1 (3), that is, ordinary ester exchange products are used, without DA dynamic covalent bonds.

[0086] Comparative Example 3 (without gradient unsealing): It is basically the same as Example 1, except that in step 1 (5) when preparing the composite skeleton component, only the high-temperature unsealing polyurethane prepolymer (15g) is used, the low-temperature unsealing type is not used, and no graphene is added.

[0087] Comparative Example 4 (Prior Technology): A commercially available conventional cold patch material formula was used, which was a cold patch binder made by diluting new aggregate (45 parts of 0-5mm fine aggregate and 35 parts of 5-10mm coarse aggregate), 90# base asphalt and diesel at a ratio of 85:15, and then adding 30% untreated oil-stone separation and recovery material. It was prepared by conventional one-time mixing method.

[0088] Comparative Example 5 (without graphene): It is basically the same as Example 1, except that edge carboxyl graphene is not added when preparing the composite framework component in step 1 (5), otherwise it is exactly the same.

[0089] Performance testing Performance tests were conducted on each example and comparative example in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) and related standards. The results are shown in Table 1.

[0090] Table 1 Performance data of each embodiment and comparative example Note: Self-healing performance test method: The formed Marshall specimen is pre-cut to half its depth (cut width 0.1mm), placed at a constant temperature of 40℃ for 24 hours, and its Marshall stability is tested. The ratio of its strength to that of the uncut specimen is the strength recovery rate. "None" indicates no self-healing function, and "—" indicates not tested (because other properties have failed).

[0091] Results Analysis As can be seen from the data in Table 1: Examples 1-4 demonstrate excellent overall performance, with all indicators significantly superior to those of the comparative examples. Furthermore, the performance of the examples is stable, indicating that the technical solutions of this invention can achieve the expected effects within the scope of the claims and have broad applicability.

[0092] The necessity of surface activation treatment: Comparative Example 1 (without interface activation) had a peeling rate as high as 21%, a 24-hour stability of only 2.9 kN, and a residual stability of only 75.2%, with all properties deteriorating, proving that surface activation treatment is the basis for interfacial adhesion and overall performance.

[0093] The irreplaceable nature of DA self-healing function: Comparative Example 2 (without DA bond) completely lost its self-healing function, and its water stability (82.1%) and freeze-thaw strength (78.5%) were significantly lower than those of Example 1, proving that the dynamic covalent bond of DA is the source of the self-healing function and also makes an important contribution to water stability.

[0094] The necessity of gradient unsealing design: The early strength of Comparative Example 3 (high temperature unsealing only) was only 4.0 kN, which was significantly lower than the 5.0 kN of Example 1, demonstrating the key role of low temperature unsealing polyurethane in early strength.

[0095] The reinforcing effect of graphene: The 24h stability (4.3kN) and freeze-thaw strength (83.2%) of Comparative Example 5 (without graphene) were lower than those of Example 1, and the self-healing rate (76%) was also slightly lower, demonstrating the nano-reinforcing and self-healing effects of graphene.

[0096] Comparison with existing technologies: Comparative Example 4 represents existing technologies, and all indicators are far lower than those of the embodiments of the present invention, demonstrating the significant progress of the present invention.

[0097] Real-world operating condition simulation and long-term storage verification: To further verify the self-healing efficiency and long-term storage stability of the present invention under actual service conditions, supplementary tests were conducted on Examples 1-4: (1) Self-healing test under simulated road conditions: At an ambient temperature of 40℃, a dynamic rolling load of 0.8MPa (simulating traffic action) was applied to the pre-cut Marshall specimen for 24 hours; the results showed that the strength recovery rate of Examples 1-4 could still reach 78%-83% (see note in Table 1), which was highly consistent with the test results of static 40℃ / 24h (78%-83%); this indicates that under the synergistic effect of dynamic load and temperature, the reversible recombination process of DA bonds was promoted, ensuring that the self-healing function under actual working conditions was effectively exerted.

[0098] (2) Long-term storage stability test: After the sealed samples of Examples 1-4 were stored at room temperature (25℃±5℃) for 6 months, appearance inspection and performance test were carried out. The results showed that all samples were free of caking and had qualified looseness. Their 24h Marshall stability retention rate was ≥93% (for example, Example 1 changed from 5.0kN to 4.65kN), and no significant decay of core performance indicators was observed. This fully proves the stability of the closed polyurethane system of the present invention in long-term storage, and fully meets the strict requirements of engineering practice for cold patching materials to be "stored in winter and used in summer".

[0099] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0100] It should be understood that the disclosed apparatus can be implemented in other ways, as illustrated in the embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative; the division of units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or communication connections shown or discussed may be through some interfaces; the indirect coupling or communication connections between devices or units may be telecommunications or other forms.

[0101] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0102] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery materials, characterized in that, It is made from the following raw materials in parts by weight: 75-85 parts of oilstone separation and recovery material; 0.3-0.8 parts of interface activator; 10-15 parts of self-healing regenerated reinforcing slurry; 6-10 parts of gradient desealing polyurethane-graphene composite skeleton component; and 3-6 parts of mineral powder. The interface activator is epichlorohydrin-modified tall oil; the self-healing regenerated reinforced slurry is made from waste asphalt recovered from oilstone separation, furan-modified vegetable oil polyol and bismaleimide through transesterification and Diels-Alder reaction, and contains reversible dynamic covalent bonds; the gradient desealing polyurethane-graphene composite framework component contains at least two closed polyurethane prepolymers with different desealing temperatures and edge carboxylated graphene.

2. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery material as described in claim 1, characterized in that, The interface activator is prepared by reacting tall oil and epichlorohydrin in a molar ratio of 1:0.8~1.2 at 80~90℃ for 3~4h under the catalysis of tetrabutylammonium bromide. Its epoxy value is 0.2-0.4mol / 100g and its acid value is 30-50mgKOH / g.

3. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery material as described in claim 1, characterized in that, In the self-healing regenerated reinforced slurry, the mass ratio of waste asphalt to furan-modified vegetable oil polyol is 60:40~80:20, and the molar ratio of furan groups to maleimide groups in bismaleimide is 1:0.8~1.2; the Diels-Alder reaction temperature is 100-120℃, and the reaction time is 0.5-1.5 hours.

4. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery material as described in claim 1, characterized in that, The furan-modified vegetable oil polyol is prepared by reacting epoxidized soybean oil and furfurylamine at a molar ratio of epoxy groups to amino groups of 1:1 at 60-80°C for 2-4 hours, and its hydroxyl value is 160-200 mg KOH / g; the bismaleimide is N,N'-4,4'-diphenylmethane bismaleimide or N,N'-m-phenylene bismaleimide.

5. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery material as described in claim 1, characterized in that, The internal composition of the gradient-desealed polyurethane-graphene composite framework component is as follows: 8-12 parts of low-temperature unblocking polyurethane prepolymer, with an unblocking temperature of 70-90℃; 5-8 parts of high-temperature deblocking polyurethane prepolymer, with a deblocking temperature of 110-130℃; One to two parts of edge-carboxylated graphene, with a carboxyl content of 5-10 mmol / g; 70-80 parts of environmentally friendly solvent oil; 0.5-1 part of dispersant stabilizer; The blocked polyurethane prepolymer is obtained by blocking the NCO-terminated prepolymer generated by the reaction of polyether polyol N220 and MDI with a blocking agent, wherein the NCO content is 3%~5% by mass, and the blocking agents are methyl ethyl ketone oxime and caprolactam, respectively; the edge-carboxylated graphene is obtained by ultrasonically exfoliating graphene oxide and mixing it with chloroacetic acid at a mass ratio of 1:5~1:8, reacting it under alkaline conditions (pH=9~11) at 60~70℃ for 2~3 hours, and then filtering, washing and drying; the dispersion stabilizer is polyhydroxyalkanoate; the environmentally friendly solvent oil is a mixture of 120# solvent oil and vegetable oil methyl ester at a mass ratio of 1:

1.

6. A method for preparing asphalt cold patching material as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Surface activation treatment of recycled material: The oilstone separation recycled material is fed into a continuous microwave drum activation chamber, and an interface activator is sprayed. It is treated for 3-8 minutes under microwave power density of 1.5-3.0kW / kg, and the material temperature is controlled at 100-130℃ to obtain surface activated recycled material. (2) Preparation of self-healing regenerated reinforced slurry: The waste asphalt recovered from oilstone separation is heated to 120-140℃, furan-modified vegetable oil polyol and organotin catalyst are added, and the transesterification reaction is carried out at 160-180℃ for 1.5-3 hours. The temperature is naturally cooled to 100-120℃, bismaleimide is added, and the reaction is stirred for 0.5-1.5 hours to form a regenerated reinforced slurry containing Diels-Alder dynamic covalent bonds; (3) Preparation of gradient unsealing polyurethane-graphene composite skeleton components: Low-temperature unsealing polyurethane prepolymer, high-temperature unsealing polyurethane prepolymer, edge carboxyl graphene, and dispersant stabilizer are added to environmentally friendly solvent oil, stirred and dissolved at 50-70℃ for 1-2 hours, and ultrasonically dispersed for 20-40 minutes to obtain composite skeleton components. (4) Stepwise agglomeration preparation of cold patching material: a. Pre-coating treatment: Put the surface-activated recycled material into the mixing tank, add the recycled reinforcing slurry preheated to 80-100℃, control the temperature difference between the recycled reinforcing slurry and the surface-activated recycled material to ≤30℃, and mix for 30-60 seconds; b. Activation: Let the mixed material stand and age in a closed mixing tank for 5-10 minutes, and control the aging temperature at 60-80℃; c. Secondary film formation: Add the composite skeleton components and mineral powder to the mixing tank, and continue mixing for 60-90 seconds until uniform; (5) Discharge the material, allow it to cool naturally to room temperature, and package it to obtain high-stability asphalt cold patching material.

7. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery materials as described in claim 6, characterized in that, The organotin catalyst mentioned in step (2) is dibutyltin dilaurate, and the amount used is 0.1%-0.3% of the total mass of waste asphalt and furan-modified vegetable oil polyol.

8. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery materials as described in claim 6, characterized in that, The ultrasonic dispersion frequency in step (3) is 20-40kHz, and the power density is 0.3-0.5W / mL.

9. The method for preparing high-stability asphalt cold patching material from oil-stone separation and recovery materials as described in claim 6, characterized in that, The mixing tank mentioned in step (4) is a twin-shaft forced mixer with heat preservation function, which is kept sealed during the mixing process.

10. The application of asphalt cold patch material as described in any one of claims 1-5 in the long-term repair of potholes on heavy-duty roads and roads in low-temperature areas.

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