A recycled cold patch asphalt mixture and a method of making the same

Abstract

The application relates to the technical field of road pit repairing, in particular to a regenerated cold repairing asphalt mixture and a preparation method thereof. The regenerated cold repairing asphalt mixture comprises the following raw materials in parts by mass: asphalt pavement recycling material 92-98 parts, mineral powder 1-3 parts, basalt fiber 0.2-1.0 parts and cold repairing asphalt 4-8 parts. The cold repairing asphalt comprises the following raw materials in parts by mass: base asphalt 85-100 parts, compatibility agent 30-40 parts, diluent 20-30 parts, modified polyurethane prepolymer 25-40 parts, anti-rutting agent 0.2-1.5 parts and anti-stripping agent 0.3-3 parts. The regenerated cold repairing asphalt mixture prepared by the application has excellent comprehensive performance in dynamic stability, anti-freezing and thawing performance, Marshall stability and self-repairing capacity, and has good economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of road pothole repair technology, specifically to a recycled cold patch asphalt mixture and its preparation method. Background Technology

[0002] With the acceleration of urbanization and the increasing demand for road traffic, the problems of asphalt pavement defects during use are becoming increasingly prominent. Among them, potholes are one of the most common defects in asphalt pavements. If not repaired in time, they will not only shorten the service life of the pavement but may also pose a serious threat to driving safety. Therefore, timely and effective repair of potholes has become particularly important.

[0003] Recycled cold-patch asphalt mixture is a type of mixture made by mixing recycled asphalt pavement material (RAP) with new aggregates, recycling agents, and cold-patch asphalt under normal or low-temperature conditions. It can be used to repair potholes and other defects in asphalt pavements. Combining recycling and cold-patch technologies, it achieves resource recycling while also possessing the advantages of cold-patch asphalt mixtures, such as requiring no heating and being easy to apply.

[0004] The strength and durability of recycled cold-mix asphalt (RAP) mixtures are often lower than those of traditional hot-mix asphalt (HMA) mixtures. The compatibility issues between aged and new asphalt in RAP, as well as the impact of the amount and type of recycling agent on mixture performance, make the mixture prone to rutting, cracking, and loosening during long-term use. Furthermore, because RAP may contain more moisture and impurities, and the addition of recycling agents may affect the adhesion between asphalt and aggregates, recycled cold-mix asphalt mixtures have poor water stability, making them prone to spalling and pumping in humid environments.

[0005] Therefore, we propose a recycled cold patch asphalt mixture and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to provide a recycled cold patch asphalt mixture and its preparation method to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A recycled cold-patch asphalt mixture comprises the following raw materials in parts by weight: 92-98 parts recycled asphalt pavement material, 1-3 parts mineral powder, 0.2-1.0 parts basalt fiber, and 4-8 parts cold-patch asphalt.

[0009] Furthermore, the cold-mixed asphalt comprises the following raw materials in parts by weight: 85-100 parts of base asphalt, 30-40 parts of compatibilizer, 20-30 parts of diluent, 25-40 parts of modified polyurethane prepolymer, 0.2-1.5 parts of anti-rutting agent, and 0.3-3 parts of anti-stripping agent.

[0010] Furthermore, the preparation method of the modified polyurethane prepolymer is as follows:

[0011] Step 1: Under nitrogen protection, acrylic rosin is heated and melted, and butanediol diglycidyl ether is added under the catalysis of triethylamine. The reaction is carried out at 120-130℃ for 6-8 hours to obtain epoxy-terminated rosin.

[0012] Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride are added to a mixed solution of ethanol and tetrahydrofuran, and triethylamine is added and mixed evenly. The mixture is reacted at 40-60℃ for 10-12 hours. After washing and drying, disulfide-modified rosin is obtained.

[0013] Step 3: Mix disulfide-modified rosin, mercapto-containing organosilicon, and photoinitiator evenly, and then irradiate with ultraviolet light to obtain organosilicon-modified polyol;

[0014] Step 4: Dehydrate the polyether polyol and organosilicon-modified polyol under vacuum at 110-120℃ for 2-3 hours, cool down to 60-70℃, add isophorone diisocyanate and dibutyltin dilaurate under nitrogen protection, mix evenly, react for 1-3 hours, add 2,2-dimethylolbutyric acid, and react for 2-4 hours to obtain the modified polyurethane prepolymer.

[0015] Furthermore, in step 1, the molar ratio of rosin acrylate to butylene glycol diglycidyl ether is 1:2.

[0016] Furthermore, in step 1, the amount of triethylamine used is 1 to 3% of the total mass of rosin acrylate and butylene glycol diglycidyl ether.

[0017] Furthermore, in step 2, the molar ratio of epoxy-terminated rosin to cystamine dihydrochloride is 1:(1-2).

[0018] Furthermore, in step 2, the amount of triethylamine used is 3 to 5% of the total mass of epoxy-terminated rosin and cystamine dihydrochloride.

[0019] Furthermore, in the mixed solution, the mass ratio of ethanol to tetrahydrofuran is 1:1.

[0020] Furthermore, in step 3, the mass ratio of disulfide-modified rosin, mercapto-containing organosilicon, and photoinitiator is 1:(0.3-0.5):(0.1-0.3).

[0021] Furthermore, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0022] Furthermore, the process conditions for ultraviolet irradiation are: irradiation with 360–400 nm ultraviolet light for 30–60 min, with an irradiation intensity of 25–35 mW / cm². 2 .

[0023] Furthermore, the preparation method of the mercapto-containing organosilicon is as follows: under nitrogen protection, 3-mercaptopropylmethyldimethoxysilane, deionized water and isopropanol are mixed evenly, hydroxyl silicone oil and tetramethylammonium hydroxide are added, and the mixture is reacted at 60-70°C for 4-6 hours. After vacuum distillation, mercapto-containing organosilicon is obtained.

[0024] Further, the mass ratio of 3-mercaptopropylmethyldimethoxysilane, deionized water, isopropanol, hydroxyl silicone oil and tetramethylammonium hydroxide is 1:(2-3):(6-8):(64-66):(1.2-1.4).

[0025] Further, the modified polyurethane prepolymer comprises the following raw materials in parts by weight: 40-50 parts of polyether polyol, 10-20 parts of organosilicon modified polyol, 70-90 parts of isophorone diisocyanate, 1-3 parts of dibutyltin dilaurate, and 2-4 parts of 2,2-dimethylolbutyric acid.

[0026] Furthermore, the compatibilizer is maleic anhydride.

[0027] Furthermore, the diluent is one or a mixture of kerosene, diesel oil, and gasoline.

[0028] Furthermore, the anti-stripping agent is vinyl bis-stearamide.

[0029] A method for preparing recycled cold-patch asphalt mixture includes the following steps:

[0030] Step S1: Heat the base asphalt to 130-150°C, add the compatibilizer, stir for 5-10 minutes, then add the modified polyurethane prepolymer, stir for 30-40 minutes, then add the diluent, anti-rutting agent and anti-stripping agent, stir evenly until the temperature drops to 80-90°C to obtain cold patch asphalt.

[0031] Step S2: Heat the recycled asphalt pavement material to 70-80℃, add the cold patch asphalt prepared in step S1, stir for 90-120s, add mineral powder and basalt fiber, stir again for 90-120s, and obtain the recycled cold patch asphalt mixture.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. The present invention relates to a recycled cold patch asphalt mixture and its preparation method, wherein a cyclic terpene structure is introduced by reacting acrylic rosin with butanediol diglycidyl ether, which provides rigidity and heat resistance, to obtain epoxy-terminated rosin; dynamic disulfide bonds are introduced by the interaction of cystamine dihydrochloride with epoxy groups, to obtain disulfide-modified rosin, which endows polyurethane with excellent self-healing properties. The self-healing mechanism of its dynamic disulfide bonds promotes the inherent self-healing ability of asphalt and achieves synergistic repair.

[0034] In this scheme, to improve the water resistance and toughness of polyurethane, 3-mercaptopropylmethyldimethoxysilane is hydrolyzed and then dehydrated and condensed with hydroxyl silicone oil to introduce hydroxyl groups, resulting in mercapto-containing organosilicon. Mercapto-olefin click reaction is used to introduce organosilicon segments into disulfide-modified rosin, improving the material's water resistance and effectively blocking moisture erosion. Simultaneously, the silanol groups in the organosilicon can form a stronger bond with the surfaces of inorganic materials such as aggregates and cementitious matrices in the road surface, effectively enhancing the curing strength of the cold-mix asphalt system and significantly improving the interfacial adhesion between the cold-mix material and the roadbed. The synergistic effect of dynamic disulfide bonds and organosilicon segments enhances shear resistance while ensuring the material maintains structural integrity under extreme environments such as high pressure and humid heat, solving the technical bottleneck of traditional cold-mix materials being prone to loosening and peeling.

[0035] 2. This invention discloses a recycled cold-patch asphalt mixture and its preparation method. The introduction of polyurethane prepolymer significantly improves the cohesive properties of the cold-patch, resulting in stronger adhesion between the cold-patch and the pothole interface. This strong adhesion effectively prevents the asphalt mixture from becoming loose or breaking at the joints prematurely after filling potholes, thus significantly improving the durability of the cold-patch. After the polyurethane prepolymer is fully mixed and cured with liquid asphalt, the asphalt is uniformly distributed in the spatial network structure formed by the polyurethane prepolymer. This not only improves the strength of the cold-patch but also ensures that the cold-patch does not become sticky or soften under high-temperature conditions, thereby meeting the usage requirements under high-temperature climate conditions and further improving durability. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In this embodiment, the recycled asphalt pavement material is taken from milled material from a highway and milled to meet the technical requirements specified in the "Technical Specification for Recycling of Highway Asphalt Pavement" (JTG / T5521—2019); the base asphalt is 70# road petroleum asphalt; the basalt fiber is 6mm in length and 15μm in diameter, sourced from Taian Songze Composite Materials Co., Ltd.; the mineral powder is grade S95; the diluent is 0# diesel oil; the anti-rutting agent is model KCCJ001, sourced from Changzhou Bochao Engineering Materials Co., Ltd.; the anti-stripping agent is vinyl bis-stearamide; the polyether polyol is grade CP450, sourced from Dow Chemical; and the hydroxyl silicone oil has a viscosity of 70mPa·s at 25℃ and a hydroxyl content of 3%, sourced from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd.

[0038] Unless otherwise specified, all the following quantities are parts by weight.

[0039] Example 1: A method for preparing recycled cold patch asphalt mixture, comprising the following processes:

[0040] Step S1: Heat 85 parts of base asphalt to 130°C, add 30 parts of compatibilizer, stir for 5 minutes, then add 25 parts of modified polyurethane prepolymer, stir for 30 minutes, then add 20 parts of diluent, 0.2 parts of anti-rutting agent and 0.3 parts of anti-stripping agent, stir evenly until the temperature drops to 80°C to obtain cold patch asphalt.

[0041] Step S2: Heat 92 parts of recycled asphalt pavement material to 70°C, add 4 parts of cold patch asphalt prepared in step S1, stir for 90 seconds, then add 1 part of mineral powder and 0.2 parts of basalt fiber, stir again for 90 seconds, and obtain recycled cold patch asphalt mixture.

[0042] The preparation method of modified polyurethane prepolymer is as follows:

[0043] Step 1: Under nitrogen protection, rosin acrylic acid is heated and melted. Butylene glycol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 120°C for 6 hours to obtain epoxy-terminated rosin. The molar ratio of rosin acrylic acid to butylene glycol diglycidyl ether is 1:2. The amount of triethylamine used is 1% of the total mass of rosin acrylic acid and butylene glycol diglycidyl ether.

[0044] Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride were dissolved in a mixed solution of ethanol and tetrahydrofuran at a mass ratio of 1:1. Triethylamine was added and mixed thoroughly. The mixture was reacted at 40°C for 10 hours. After washing and drying, disulfide-modified rosin was obtained. The molar ratio of epoxy-terminated rosin to cystamine dihydrochloride was 1:1. The amount of triethylamine used was 3% of the total mass of epoxy-terminated rosin and cystamine dihydrochloride.

[0045] Step 3: Under nitrogen protection, 0.2 parts of 3-mercaptopropylmethyldimethoxysilane, 0.4 parts of deionized water and 1.2 parts of isopropanol were mixed evenly, and 12.8 parts of hydroxyl silicone oil and 0.24 parts of tetramethylammonium hydroxide were added. The mixture was reacted at 60°C for 4 hours. After vacuum distillation, mercapto-containing organosilicon was obtained.

[0046] Ten parts of disulfide-modified rosin, three parts of mercapto-containing organosilicon, and one part of 2-hydroxy-2-methyl-1-phenyl-1-propanone were mixed evenly and then irradiated with 360 nm ultraviolet light for 30 min at an irradiation intensity of 35 mW / cm². 2 Organosilicon-modified polyols were obtained;

[0047] Step 4: Dehydrate 40 parts of polyether polyol and 10 parts of organosilicon modified polyol under vacuum at 110°C for 2 hours, cool down to 60°C, add 70 parts of isophorone diisocyanate and 1 part of dibutyltin dilaurate under nitrogen protection, mix evenly, react for 1 hour, add 2 parts of 2,2-dimethylolbutyric acid, react for 2 hours to obtain modified polyurethane prepolymer.

[0048] Example 2: A method for preparing recycled cold-patch asphalt mixture, comprising the following processes:

[0049] Step S1: Heat 90 parts of base asphalt to 140°C, add 35 parts of compatibilizer, stir for 8 minutes, then add 35 parts of modified polyurethane prepolymer, stir for 35 minutes, then add 25 parts of diluent, 1 part of anti-rutting agent and 2 parts of anti-stripping agent, stir evenly until the temperature drops to 85°C to obtain cold patch asphalt.

[0050] Step S2: Heat 96 parts of recycled asphalt pavement material to 75°C, add 6 parts of cold patch asphalt prepared in step S1, stir for 100s, add 2 parts of mineral powder and 0.8 parts of basalt fiber, stir again for 100s, and obtain recycled cold patch asphalt mixture.

[0051] The preparation method of modified polyurethane prepolymer is as follows:

[0052] Step 1: Under nitrogen protection, acrylic rosin was heated and melted. Butylene glycol diglycidyl ether was added under the catalysis of triethylamine, and the reaction was carried out at 125°C for 7 hours to obtain epoxy-terminated rosin. The molar ratio of acrylic rosin to butylene glycol diglycidyl ether was 1:2. The amount of triethylamine used was 2% of the total mass of acrylic rosin and butylene glycol diglycidyl ether.

[0053] Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride were dissolved in a mixed solution of ethanol and tetrahydrofuran at a mass ratio of 1:1. Triethylamine was added and mixed thoroughly. The mixture was reacted at 50°C for 11 hours. After washing and drying, disulfide-modified rosin was obtained. The molar ratio of epoxy-terminated rosin to cystamine dihydrochloride was 1:1.5. The amount of triethylamine used was 4% of the total mass of epoxy-terminated rosin and cystamine dihydrochloride.

[0054] Step 3: Under nitrogen protection, 0.2 parts of 3-mercaptopropylmethyldimethoxysilane, 0.5 parts of deionized water and 1.4 parts of isopropanol were mixed evenly, 13 parts of hydroxyl silicone oil and 0.26 parts of tetramethylammonium hydroxide were added, and the mixture was reacted at 65°C for 5 hours. After vacuum distillation, mercapto-containing organosilicon was obtained.

[0055] 15 parts of disulfide-modified rosin, 6 parts of mercapto-containing organosilicon, and 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone were mixed evenly and then irradiated with 380 nm ultraviolet light for 40 min at an irradiation intensity of 30 mW / cm². 2 Organosilicon-modified polyols were obtained;

[0056] Step 4: Dehydrate 45 parts of polyether polyol and 15 parts of organosilicon modified polyol under vacuum at 115°C for 2.5 h, cool down to 65°C, add 80 parts of isophorone diisocyanate and 2 parts of dibutyltin dilaurate under nitrogen protection, mix evenly, react for 2 h, add 3 parts of 2,2-dimethylolbutyric acid, react for 3 h to obtain modified polyurethane prepolymer.

[0057] Example 3: A method for preparing recycled cold-patch asphalt mixture, comprising the following processes:

[0058] Step S1: Heat 100 parts of base asphalt to 150°C, add 40 parts of compatibilizer, stir for 10 minutes, then add 40 parts of modified polyurethane prepolymer, stir for 40 minutes, then add 30 parts of diluent, 1.5 parts of anti-rutting agent and 3 parts of anti-stripping agent, stir evenly until the temperature drops to 90°C to obtain cold patch asphalt.

[0059] Step S2: Heat 98 parts of recycled asphalt pavement material to 80°C, add 8 parts of cold patch asphalt prepared in step S1, stir for 120 seconds, add 3 parts of mineral powder and 1.0 part of basalt fiber, stir again for 120 seconds, and obtain recycled cold patch asphalt mixture.

[0060] The preparation method of modified polyurethane prepolymer is as follows:

[0061] Step 1: Under nitrogen protection, rosin acrylic acid is heated and melted. Butylene glycol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 130°C for 8 hours to obtain epoxy-terminated rosin. The molar ratio of rosin acrylic acid to butylene glycol diglycidyl ether is 1:2. The amount of triethylamine used is 3% of the total mass of rosin acrylic acid and butylene glycol diglycidyl ether.

[0062] Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride were dissolved in a mixed solution of ethanol and tetrahydrofuran at a mass ratio of 1:1. Triethylamine was added and mixed thoroughly. The mixture was reacted at 60°C for 12 hours. After washing and drying, disulfide-modified rosin was obtained. The molar ratio of epoxy-terminated rosin to cystamine dihydrochloride was 1:2. The amount of triethylamine used was 5% of the total mass of epoxy-terminated rosin and cystamine dihydrochloride.

[0063] Step 3: Under nitrogen protection, 0.2 parts of 3-mercaptopropylmethyldimethoxysilane, 0.6 parts of deionized water and 1.6 parts of isopropanol were mixed evenly, and 13.2 parts of hydroxyl silicone oil and 0.28 parts of tetramethylammonium hydroxide were added. The mixture was reacted at 70°C for 6 hours. After vacuum distillation, mercapto-containing organosilicon was obtained.

[0064] 20 parts of disulfide-modified rosin, 10 parts of mercapto-containing organosilicon, and 6 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone were mixed evenly and irradiated with 400 nm ultraviolet light for 60 min at an irradiation intensity of 25 mW / cm². 2 Organosilicon-modified polyols were obtained;

[0065] Step 4: Dehydrate 50 parts of polyether polyol and 20 parts of organosilicon modified polyol under vacuum at 120°C for 3 hours, cool down to 70°C, add 90 parts of isophorone diisocyanate and 3 parts of dibutyltin dilaurate under nitrogen protection, mix evenly, react for 3 hours, add 4 parts of 2,2-dimethylolbutyric acid, react for 4 hours to obtain modified polyurethane prepolymer.

[0066] Comparative Example 1: A method for preparing recycled cold patch asphalt mixture, comprising the following processes:

[0067] Compared with Example 2, Comparative Example 1 replaced the organosilicon-modified polyol with the same mass of epoxy-terminated rosin, and the other steps were the same as in Example 2.

[0068] Comparative Example 2: A method for preparing recycled cold patch asphalt mixture, comprising the following processes:

[0069] The preparation method of modified polyurethane prepolymer is as follows:

[0070] Step 1: Under nitrogen protection, acrylic rosin was heated and melted. Butylene glycol diglycidyl ether was added under the catalysis of triethylamine, and the reaction was carried out at 125°C for 7 hours to obtain epoxy-terminated rosin. The molar ratio of acrylic rosin to butylene glycol diglycidyl ether was 1:2. The amount of triethylamine used was 2% of the total mass of acrylic rosin and butylene glycol diglycidyl ether.

[0071] Step 2: Under nitrogen protection, 0.2 parts of 3-mercaptopropylmethyldimethoxysilane, 0.5 parts of deionized water and 1.4 parts of isopropanol were mixed evenly, 13 parts of hydroxyl silicone oil and 0.26 parts of tetramethylammonium hydroxide were added, and the mixture was reacted at 65°C for 5 hours. After vacuum distillation, mercapto-containing organosilicon was obtained.

[0072] 15 parts of epoxy-terminated rosin, 6 parts of mercapto-containing organosilicon, and 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone were mixed evenly and then irradiated with 380 nm ultraviolet light for 40 min at an irradiation intensity of 30 mW / cm². 2 Organosilicon-modified polyols were obtained;

[0073] Step 3: Dehydrate 45 parts of polyether polyol and 15 parts of organosilicon modified polyol under vacuum at 115°C for 2.5 h, cool down to 65°C, add 80 parts of isophorone diisocyanate and 2 parts of dibutyltin dilaurate under nitrogen protection, mix evenly, react for 2 h, add 3 parts of 2,2-dimethylolbutyric acid, react for 3 h to obtain modified polyurethane prepolymer;

[0074] Compared with Example 2, Comparative Example 2 does not introduce cystamine dihydrochloride, replaces disulfide-modified rosin with epoxy-terminated rosin, and the other steps are the same as in Example 2.

[0075] Comparative Example 3: A method for preparing recycled cold patch asphalt mixture, comprising the following processes:

[0076] The preparation method of modified polyurethane prepolymer is as follows:

[0077] Step 1: Under nitrogen protection, acrylic rosin was heated and melted. Butylene glycol diglycidyl ether was added under the catalysis of triethylamine, and the reaction was carried out at 125°C for 7 hours to obtain epoxy-terminated rosin. The molar ratio of acrylic rosin to butylene glycol diglycidyl ether was 1:2. The amount of triethylamine used was 2% of the total mass of acrylic rosin and butylene glycol diglycidyl ether.

[0078] Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride were dissolved in a mixed solution of ethanol and tetrahydrofuran at a mass ratio of 1:1. Triethylamine was added and mixed thoroughly. The mixture was reacted at 50°C for 11 hours. After washing and drying, disulfide-modified rosin was obtained. The molar ratio of epoxy-terminated rosin to cystamine dihydrochloride was 1:1.5. The amount of triethylamine used was 4% of the total mass of epoxy-terminated rosin and cystamine dihydrochloride.

[0079] Step 3: Dehydrate 45 parts of polyether polyol and 15 parts of disulfide-modified rosin under vacuum at 115°C for 2.5 h, cool down to 65°C, add 80 parts of isophorone diisocyanate and 2 parts of dibutyltin dilaurate under nitrogen protection, mix evenly, react for 2 h, add 3 parts of 2,2-dimethylolbutyric acid, react for 3 h to obtain modified polyurethane prepolymer.

[0080] Compared with Example 2, Comparative Example 3 does not introduce mercapto-containing organosilicon, but replaces the organosilicon-modified polyol with disulfide-modified rosin, and the other steps are the same as in Example 2.

[0081] experiment:

[0082] 1. Dynamic stability test: Take the recycled cold patch asphalt mixtures obtained in Examples 1 to 3 and Comparative Examples 1 to 3, and test them according to JTG E20-2011. The specimen size is 300mm×300mm×50mm, the test temperature is 60℃, and the loading wheel is rolled back and forth at a frequency of 42 times / min and a pressure of 0.7MPa for 60min.

[0083] 2. Freeze-thaw splitting strength ratio test: The recycled cold patch asphalt mixtures obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to freeze-thaw cycles under the conditions specified in JTG E20-2011 to determine the splitting strength ratio of the specimens before and after water damage, thereby evaluating the water stability of the asphalt mixture. The test temperature was 25℃ and the loading rate was 50mm / min.

[0084] 3. Marshall stability test: Take the recycled cold patch asphalt mixtures obtained in Examples 1-3 and Comparative Examples 1-3, and the Marshall specimen size is Φ101.6mm×63.5mm. Put them into the mold at room temperature, compact them on both sides 75 times at -5℃, demold them, and conduct the Marshall strength test according to the provisions of JTGE20-2011. Record the data.

[0085] 4. Self-healing performance test: Cold-patch asphalt obtained in Examples 1-3 and Comparative Examples 1-3 was used to evaluate the self-healing ability of cold-patch asphalt for macroscopic cracks using a fracture-repair-fracture test. The specimens were divided into two groups: Group 1 consisted of uncut specimens, which underwent a ductility test immediately at 10°C; the ductility data for this group was recorded as L1. Group 2 consisted of cracked specimens, in which a crack of a certain depth was cut in the middle of the specimen, leaving a 4.5 mm uncut section. After being placed at 25°C for 8 hours, a ductility test was conducted at 10°C; the ductility data for this group was recorded as L2. The self-healing efficiency was L2 / L1×100%.

[0086] The test results are as follows:

[0087]

[0088] Based on the data in the table above, the following conclusions can be clearly drawn:

[0089] Based on Examples 1-3 and Comparative Examples 1-3, it can be seen that the recycled cold-patch asphalt mixture prepared by this invention exhibits excellent comprehensive performance in terms of dynamic stability, freeze-thaw resistance, Marshall stability, and self-healing ability, demonstrating good economic and environmental benefits. This material can not only effectively extend the service life of roads and reduce maintenance frequency, thereby lowering maintenance costs, but also reduce resource waste and environmental pollution through the recycling of waste asphalt materials, aligning with the concept of sustainable development.

[0090] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A recycled cold-patch asphalt mixture, characterized in that: The raw materials include the following parts by weight: 92-98 parts recycled asphalt pavement material, 1-3 parts mineral powder, 0.2-1.0 parts basalt fiber, and 4-8 parts cold patch asphalt; The composition includes 85-100 parts base asphalt, 30-40 parts compatibilizer, 20-30 parts diluent, 25-40 parts modified polyurethane prepolymer, 0.2-1.5 parts anti-rutting agent, and 0.3-3 parts anti-stripping agent. The preparation method of the modified polyurethane prepolymer is as follows: Step 1: Under nitrogen protection, acrylic rosin is heated and melted, and butanediol diglycidyl ether is added under the catalysis of triethylamine. The reaction is carried out at 120-130℃ for 6-8 hours to obtain epoxy-terminated rosin. Step 2: Under nitrogen protection, epoxy-terminated rosin and cystamine dihydrochloride are added to a mixed solution of ethanol and tetrahydrofuran, and triethylamine is added and mixed evenly. The mixture is reacted at 40-60℃ for 10-12 hours. After washing and drying, disulfide-modified rosin is obtained. Step 3: Mix disulfide bond modified rosin, mercapto-containing organosilicon and photoinitiator evenly, and then irradiate with ultraviolet light to obtain organosilicon modified polyol; Step 4: Dehydrate the polyether polyol and organosilicon-modified polyol under vacuum at 110-120℃ for 2-3 hours, cool down to 60-70℃, add isophorone diisocyanate and dibutyltin dilaurate under nitrogen protection, mix evenly, react for 1-3 hours, add 2,2-dimethylolbutyric acid, and react for 2-4 hours to obtain the modified polyurethane prepolymer.

2. The recycled cold-patch asphalt mixture according to claim 1, characterized in that: In step 1, the molar ratio of acrylic rosin to butylene glycol diglycidyl ether is 1:

2.

3. The recycled cold-patch asphalt mixture according to claim 1, characterized in that: In step 2, the molar ratio of epoxy-terminated rosin to cystamine dihydrochloride is 1:(1-2).

4. The recycled cold-patch asphalt mixture according to claim 1, characterized in that: In step 3, the mass ratio of disulfide bond modified rosin, mercapto-containing organosilicon and photoinitiator is 1:(0.3-0.5):(0.1-0.3).

5. The recycled cold-patch asphalt mixture according to claim 1, characterized in that: The preparation method of the mercapto-containing organosilicon is as follows: under nitrogen protection, 3-mercaptopropylmethyldimethoxysilane, deionized water and isopropanol are mixed evenly, hydroxyl silicone oil and tetramethylammonium hydroxide are added, and the mixture is reacted at 60-70°C for 4-6 hours. After vacuum distillation, the mercapto-containing organosilicon is obtained.

6. The recycled cold-patch asphalt mixture according to claim 1, characterized in that: The modified polyurethane prepolymer comprises the following raw materials in parts by weight: 40-50 parts of polyether polyol, 10-20 parts of organosilicon modified polyol, 70-90 parts of isophorone diisocyanate, 1-3 parts of dibutyltin dilaurate, and 2-4 parts of 2,2-dimethylolbutyric acid.

7. A recycled cold-patch asphalt mixture according to claim 1, characterized in that: The diluent is one or a mixture of kerosene, diesel, and gasoline.

8. A method for preparing a recycled cold-patch asphalt mixture according to any one of claims 1 to 7, characterized in that: Includes the following steps: Step S1: Heat the base asphalt to 130-150°C, add the compatibilizer, stir for 5-10 minutes, then add the modified polyurethane prepolymer, stir for 30-40 minutes, then add the diluent, anti-rutting agent and anti-stripping agent, stir evenly until the temperature drops to 80-90°C to obtain cold patch asphalt. Step S2: Heat the recycled asphalt pavement material to 70-80℃, add the cold patch asphalt prepared in step S1, stir for 90-120s, then add mineral powder and basalt fiber, stir again for 90-120s, and obtain the recycled cold patch asphalt mixture.

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