Instantly-cured high-strength asphalt cold patch material and preparation method thereof

Abstract

The application provides a high-strength asphalt cold patching material and a preparation method thereof, belongs to the technical field of asphalt polymer materials, and the asphalt cold patching material comprises road petroleum asphalt, anionic emulsified asphalt, EAS-GMA, a core-shell structure composite modifier, epoxy soybean oil, basalt machine-made sand, limestone gravel, KH-550 and the like. The EAS-GMA is prepared by the reaction of polyamide resin, epoxy resin and stannous octoate, and then modified by KH-570. The core-shell structure composite modifier is prepared by the reaction of an isocyanate-terminated polyurethane prepolymer, epoxy resin and benzyl glycidyl ether, and then emulsified, and then MMA and KH-570 are added for adsorption, and then KPS is added for initiating reaction. The asphalt cold patching material is prepared by the synergy of multiple components and process optimization, breaks through the technical bottlenecks of long curing period, low initial strength, poor adhesion and insufficient durability of traditional cold patching materials, and realizes the unification of immediate compression and solidification and high strength and durability.

Description

Technical Field

[0001] This invention pertains to the field of asphalt polymer materials technology, specifically relating to a high-strength cold patching material that can be pressed and solidified immediately, and its preparation method. Background Technology

[0002] Asphalt pavements are widely used in highway and municipal transportation construction due to their advantages such as smoothness, wear resistance, and driving comfort. However, under the long-term effects of vehicle loads and climatic conditions, they are prone to potholes, cracks, and other defects. If not repaired in time, these defects will accelerate pavement damage, threaten driving safety, and shorten the service life of the road. Traditional pavement repair mainly relies on hot-mix asphalt mixtures. Although these mixtures have stable road performance, they require high-temperature heating, complex construction equipment, and are limited by low-temperature and humid environments, resulting in delayed traffic opening and making it difficult to meet the needs for rapid emergency repair of scattered potholes.

[0003] Therefore, cold patch asphalt has emerged as a material for room-temperature construction. Its core principle is to mix unheated aggregate with diluted asphalt or modified emulsified asphalt. It requires no heating equipment, is easy to apply, and is stable in storage. It can be used in a wide temperature range of -30℃ to 50℃ and in humid conditions, significantly reducing the construction threshold and environmental impact. Based on the binder formation mechanism, cold patch asphalt is mainly divided into three categories: solvent-based, emulsified, and reactive. Solvent-based asphalt reduces asphalt viscosity through a diluent to achieve room-temperature mixing, relying on the volatilization of the diluent to form strength. Emulsified asphalt utilizes the dispersion stability of emulsified asphalt, breaking down and solidifying after construction. Reactive asphalt improves performance through the chemical reaction between additives and the binder.

[0004] However, existing cold patch materials still face significant technical bottlenecks, as follows: Solvent-based materials rely on the volatilization of diluents for strength development, are highly susceptible to environmental impact, and are prone to VOC pollution; while emulsified and reactive materials offer improved environmental friendliness, their initial strength is insufficient, their curing period remains long, and they require prolonged traffic closure after compaction. Furthermore, traditional cold patch materials suffer from insufficient adhesion and durability, leading to loosening and peeling after repair, and exhibiting weak resistance to deformation under heavy traffic. In addition, the compaction degree is difficult to guarantee when using small compaction equipment, resulting in poor bonding between the repair layer and the original road surface, easily causing secondary damage.

[0005] Therefore, it is necessary to continuously optimize the binder modification technology and develop high-efficiency active additives and asphalt compatibility to create new cold patch materials that combine the characteristics of immediate compaction and solidification with strong bonding performance. This will enable the materials to achieve rapid molding after compaction, meet initial strength standards, and maintain stable long-term performance, thus addressing the current technical shortcomings of cold patch materials in emergency maintenance and heavy-load road applications. Summary of the Invention

[0006] To address the problems of long curing time, poor adhesion, insufficient initial strength, and unstable long-term performance of existing asphalt cold patch materials, this invention provides a high-strength asphalt cold patch material that cures upon pressure and its preparation method. A special process is used to prepare EAS-GMA and a core-shell structured composite modifier, which are then compounded with road petroleum asphalt, anionic emulsified asphalt, epoxidized soybean oil, basalt manufactured sand, limestone chips, KH-550, active fillers, lignin fibers, and other components in a specific ratio to prepare the cold patch material. Through multi-component synergy and process optimization, this invention overcomes the technical bottlenecks of traditional cold patch materials, such as long curing time, low initial strength, poor adhesion, and insufficient durability, achieving a balance between immediate curing and high strength and durability. This effectively solves the technical challenges of emergency repair of scattered potholes and maintenance of heavy-load road sections. The specific technical solution is as follows:

[0007] A high-strength cold-patch asphalt material that can be pressed and solidified immediately comprises the following raw materials in parts by weight: 7-10 parts road petroleum asphalt, 0.8-1.2 parts anionic emulsified asphalt, 1.5-2.5 parts EAS-GMA, 1.0-2.0 parts core-shell structure composite modifier, 0.3-0.5 parts epoxidized soybean oil, 95-105 parts basalt manufactured sand, 35-45 parts limestone chips, 0.1-0.2 parts KH-550, 5-7 parts active filler, 0.2-0.3 parts lignin fiber, 0.3-0.6 parts accelerator, 0.1-0.2 parts anti-aging agent, and 0.5-1.0 parts water loss resistant agent;

[0008] The EAS-GMA is obtained by reacting polyamide resin, epoxy resin, and stannous octoate in xylene at a mass ratio of (45-55):(35-45):(0.4-0.6) to obtain an epoxy-amide prepolymer, which is then modified with KH-570 and obtained by vacuum distillation.

[0009] The core-shell structure composite modifier is prepared by reacting isocyanate-terminated polyurethane prepolymer, epoxy resin, benzyl glycidyl ether, and DBTDL in a mass ratio of (55-65):(30-40):(3-7):(0.1-0.3) to obtain the core liquid; then the core liquid is emulsified in deionized water containing SDS, and MMA and KH-570 are added for adsorption, and KPS is used to initiate the reaction. The product is then obtained by centrifugation, washing, vacuum drying, and sieving.

[0010] Among the above raw materials, the road petroleum asphalt is 70# road petroleum asphalt.

[0011] Of the above raw materials, the water-damage resistant agent is slaked lime.

[0012] The active filler in the above raw materials includes limestone powder and silica fume in a mass ratio of (4-6):(1-1.5).

[0013] The coagulant in the above raw materials includes triethyl citrate and nano-calcium carbonate in a mass ratio of 1:(1.5-2).

[0014] Among the above raw materials, the anti-aging agent includes antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:(0.8-1.2).

[0015] Furthermore, the preparation method of EAS-GMA includes the following steps: by mass, 45 to 55 parts of polyamide resin are added to 100 to 120 parts of xylene, stirred and dissolved, 35 to 45 parts of epoxy resin are added dropwise, 0.4 to 0.6 parts of stannous octoate are added, and the mixture is stirred and reacted in a temperature range of 85°C to 90°C to obtain an epoxy-amide prepolymer, 3 to 5 parts of KH-570 are added dropwise, and the reaction is continued at 100°C to 110°C, followed by vacuum distillation to obtain EAS-GMA.

[0016] In the above-mentioned preparation method of EAS-GMA, the stirring and dissolving is carried out at 100℃~110℃, and then the temperature is lowered to 85℃~90℃; the stirring reaction time is 2.5h~3.0h; the reaction time is continued for 1.5h~2h; and the vacuum distillation is carried out to recover all xylene.

[0017] Furthermore, the preparation method of the core-shell structure composite modifier includes the following steps: under nitrogen protection, isocyanate-terminated polyurethane prepolymer, epoxy resin, benzyl glycidyl ether, and DBTDL are reacted in a mass ratio of (55-65):(30-40):(3-7):(0.1-0.3) to obtain a core liquid; by mass fraction, 1.2-1.8 parts of SDS are added to 200-300 parts of deionized water and stirred to dissolve, 30-40 parts of the core liquid are added, and emulsification is carried out to obtain an emulsion; 5-8 parts of MMA and 0.5-1.0 parts of KH-570 are premixed and added dropwise to the emulsion, stirred and adsorbed, 0.2-0.4 parts of KPS are added, and the mixture is stirred and reacted at 70-75℃ for 3.5-4 hours. After cooling to room temperature, the mixture is centrifuged, the precipitate is collected, washed, vacuum dried, and sieved to obtain the core-shell structure composite modifier.

[0018] In the above-mentioned method for preparing the core-shell structure composite modifier, the core liquid is prepared by stirring and reacting at 60℃~65℃ for 2h~2.5h.

[0019] In the above-mentioned preparation method of core-shell structure composite modifier, the emulsification is carried out at 9000rpm to 11000rpm for 8min to 12min until the D90 is below 150μm; the stirring adsorption is carried out at 50℃ to 55℃ for 30min to 60min.

[0020] In the preparation method of the above-mentioned core-shell structure composite modifier, the KPS is pre-diluted with 10 to 12 parts of deionized water and then added; the centrifugation is carried out at 4000 rpm to 5000 rpm for 10 to 15 minutes; the washing is done with deionized water; the vacuum drying is carried out at 45℃ to 50℃ and -0.07 MPa to -0.08 MPa for 10 to 14 hours; and the sieve mesh size is 200 to 250 mesh.

[0021] The preparation method of the above-mentioned high-strength cold-applied asphalt patching material that can be pressed and solidified immediately includes the following steps:

[0022] S1: According to the formula, mix basalt manufactured sand, limestone rock chips and KH-550 evenly to obtain pre-activated aggregate;

[0023] S2: According to the formula, heat the road petroleum asphalt to 120℃~130℃, add EAS-GMA, mix evenly, cool to 70℃~80℃, add anionic emulsified asphalt and epoxidized soybean oil, mix evenly, and obtain composite binder;

[0024] S3: Add pre-activated aggregate to the mixer and stir at room temperature; add composite binder and stir; add active filler and lignin fiber and stir; add core-shell structure composite modifier and stir; finally add accelerator, anti-aging agent and anti-water loss agent and stir evenly to obtain asphalt cold patching material.

[0025] The present invention provides a high-strength cold-applied asphalt patching material that can be pressed and solidified immediately, and its preparation method, with the following beneficial effects:

[0026] I. This invention's cold patch material, through multi-component synergy and process optimization, overcomes the technical bottlenecks of traditional cold patch materials, such as long curing cycles, low initial strength, poor adhesion, and insufficient durability, achieving a balance between immediate curing and high strength and durability. After compaction, it can quickly form the initial strength required for traffic opening, while exhibiting excellent resistance to water damage, freeze-thaw cycles, aging, and deformation during long-term use. It can effectively solve the technical challenges of emergency repair of scattered potholes and maintenance of heavy-load road sections.

[0027] II. EAS-GMA rapidly increases the viscosity and cohesion of the binder through the physical entanglement of the epoxy-amide prepolymer and its reaction with the asphalt, laying the foundation for initial strength. The siloxane groups form chemical bonds with the aggregate, solving the problem of loosening and spalling. The PMMA shell of the core-shell structure modifier ruptures after compaction, and the -NCO groups in the core chemically cross-link with water and epoxy groups, becoming the core for long-term strength. The PMMA shell also improves interfacial compatibility and resistance to deformation.

[0028] Third, triethyl citrate and nano-calcium carbonate are compounded to precisely match the curing rate and strength formation rhythm; limestone powder and silica fume active filler, KH-550, and epoxidized soybean oil synergistically optimize the aggregate-asphalt interface, fill micropores, improve flexibility, and resist water erosion and aging; antioxidant 1010 and UV-531 anti-aging agent, and quicklime anti-water loss agent specifically enhance durability. The basalt manufactured sand and limestone chip aggregates are designed with a specific particle size range and low moisture content to ensure the adhesion and compaction density of the aggregate and binder, providing a physical basis for strength formation.

[0029] IV. In the mixing preparation method, basalt manufactured sand, limestone rock chips, and KH-550 are mixed in advance. The amino groups of KH-550 react with the hydroxyl groups on the aggregate surface, activating the aggregate surface and creating conditions for subsequent chemical bonding with the binder, thus improving the interfacial bonding strength. EAS-GMA is added after the road petroleum asphalt is heated to ensure thorough mixing; after cooling, anionic emulsified asphalt and epoxidized soybean oil are added to avoid high-temperature damage to the stability of the emulsified asphalt. Simultaneously, the epoxidized soybean oil improves the flexibility of the binder, forming a high-strength and flexible composite binder system. The room-temperature mixing process leverages the core advantage of cold patching materials, which do not require heating, while also ensuring the workability of the mixture.

[0030] In summary, cold-applied filler material constructs an integrated system of physical curing, chemical curing, and interface strengthening: the immediate strengthening of EAS-GMA and the long-term enhancement of the core-shell modifier form a synergy in the time dimension, solving the problem of difficulty in achieving both initial strength and long-term strength; the accelerator accelerates curing, the active filler fills and densifies, and the interface modifier enhances adhesion, forming a synergy in the functional dimension, comprehensively improving adhesion, water stability, and anti-aging properties; the precise matching of the dosage of each component and the preparation parameters ensures that the effects of multiple components are superimposed rather than antagonistic, ultimately achieving the comprehensive advantages of immediate curing, high strength and durability, and convenient construction. Detailed Implementation

[0031] The present invention will be further described below with reference to specific implementation examples, but the present invention is not limited to these embodiments.

[0032] Definitions:

[0033] EAS-GMA is an epoxy-amide-siloxane ternary grafting modifier;

[0034] KH-550 is 3-aminopropyltriethoxysilane;

[0035] KH-570 is 3-methacryloyloxypropyltrimethoxysilane;

[0036] DBTDL is dibutyltin dilaurate;

[0037] SDS is sodium dodecyl sulfate;

[0038] MMA is a monomer of methyl methacrylate;

[0039] KPS stands for potassium persulfate.

[0040] Example 1

[0041] A high-strength cold-patch asphalt material that can be pressed and solidified immediately comprises the following raw materials in parts by weight: 8.5 parts road petroleum asphalt, 1 part anionic emulsified asphalt, 2 parts EAS-GMA, 1.5 parts core-shell structure composite modifier, 0.4 parts epoxidized soybean oil, 100 parts basalt manufactured sand, 40 parts limestone chips, 0.15 parts KH-550, 6 parts active filler, 0.25 parts lignin fiber, 0.5 parts accelerator, 0.15 parts anti-aging agent, and 0.8 parts water loss resistant agent. The road petroleum asphalt is 70# road petroleum asphalt; the water loss resistant agent is hydrated lime; the active filler includes limestone powder and silica fume in a mass ratio of 5:1.3; the accelerator includes triethyl citrate and nano-calcium carbonate in a mass ratio of 1:1.8; and the anti-aging agent includes antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1.

[0042] The preparation method of EAS-GMA includes the following steps: 50 parts by mass of polyamide resin (type 650) are added to 110 parts by xylene, and the mixture is refluxed and stirred at 105℃ and 350rpm for 25min to dissolve. The mixture is then cooled to 88℃, and 40 parts by mass of epoxy resin (type E-51) are added dropwise at a rate of 0.9mL / min. 0.5 parts by mass of stannous octoate are added, and the mixture is stirred at 350rpm for 2.5h in the temperature range of 85℃ to 90℃ to obtain an epoxy-amide prepolymer. 4 parts by mass of KH-570 are added dropwise, and the mixture is heated to 105℃ and stirred at 350rpm for 1.5h. All xylene is recovered by vacuum distillation at 85℃, and the mixture is cooled to room temperature to obtain an epoxy-amide-siloxane ternary graft modifier, named EAS-GMA.

[0043] The preparation method of the core-shell structure composite modifier includes the following steps: Under nitrogen protection, isocyanate-terminated polyurethane prepolymer, epoxy resin (E-44), benzyl glycidyl ether, and DBTDL are reacted at a mass ratio of 60:35:5:0.2 at a temperature range of 60℃~65℃ and stirred at 280rpm for 2h to obtain the core liquid; by mass, 1.5 parts of SDS are added to 250 parts of deionized water and stirred at 350rpm to dissolve, then 35 parts of the core liquid are added and emulsified at 10000rpm for 10min until the D90 is below 150μm to obtain the emulsion; 6.5 parts of MMA and 0.8 parts of KH- After premixing with 570, it was added dropwise to the emulsion and stirred at 52℃ and 350rpm for 45min for adsorption. Then, 0.3 parts of KPS (pre-diluted with 11 parts of deionized water) were added. The temperature was raised to 70℃~75℃ and stirred at 350rpm for 3.5h (to allow MMA to polymerize on the surface of the core droplet to form a PMMA shell, while KH-570 participated in the reaction to enhance interfacial bonding). The mixture was cooled to room temperature, centrifuged at 4500rpm for 12min, and the precipitate was collected. The precipitate was washed three times with deionized water to remove residual SDS and KPS. The mixture was then vacuum dried at 58℃ for 12h and passed through a 200-mesh sieve to obtain the core-shell structure composite modifier.

[0044] The preparation method of the above-mentioned high-strength cold-applied asphalt patching material that can be pressed and solidified immediately includes the following steps:

[0045] S1: According to the formula, mix basalt manufactured sand, limestone rock chips and KH-550 evenly to obtain pre-activated aggregate;

[0046] S2: According to the formula, heat the road petroleum asphalt to 125℃, add EAS-GMA, mix evenly, cool to 75℃, add anionic emulsified asphalt and epoxidized soybean oil, mix evenly, and obtain composite binder;

[0047] S3: Add pre-activated aggregate to the mixer and stir at room temperature for 1 minute; add composite binder and continue stirring for 3 minutes; add active filler and lignin fiber and continue stirring for 2 minutes; add core-shell structure composite modifier and continue stirring for 1 minute; finally add accelerator, anti-aging agent and anti-water loss agent and continue stirring for 4 minutes until the mixture is uniform and free of white spots, thus obtaining asphalt cold patching material.

[0048] Example 2

[0049] A high-strength cold-patch asphalt material that can be pressed and solidified immediately comprises the following raw materials in parts by weight: 7 parts road petroleum asphalt, 1.2 parts anionic emulsified asphalt, 1.5 parts EAS-GMA, 2.0 parts core-shell structure composite modifier, 0.3 parts epoxidized soybean oil, 105 parts basalt manufactured sand, 35 parts limestone rock chips, 0.2 parts KH-550, 5 parts active filler, 0.3 parts lignin fiber, 0.3 parts accelerator, 0.2 parts anti-aging agent, and 0.5 parts water loss resistant agent. The road petroleum asphalt is 70# road petroleum asphalt; the water loss resistant agent is hydrated lime; the active filler includes limestone powder and silica fume in a 6:1 mass ratio; the accelerator includes triethyl citrate and nano-calcium carbonate in a 1:2 mass ratio; and the anti-aging agent includes antioxidant 1010 and ultraviolet absorber UV-531 in a 1:0.8 mass ratio.

[0050] The preparation method of EAS-GMA includes the following steps: 45 parts by mass of polyamide resin (type 650) are added to 120 parts by xylene, and the mixture is refluxed and stirred at 100℃ and 300rpm for 30min to dissolve. The mixture is then cooled to 85℃, and 35 parts by mass of epoxy resin (type E-51) are added dropwise at a rate of 1mL / min. 0.6 parts by mass of stannous octoate are added, and the mixture is stirred at 300rpm for 2.5h in the temperature range of 85℃ to 90℃ to obtain an epoxy-amide prepolymer. 5 parts by mass of KH-570 are added dropwise, and the mixture is heated to 100℃ and stirred at 300rpm for 2h. All xylene is recovered by vacuum distillation at 80℃, and the mixture is cooled to room temperature to obtain an epoxy-amide-siloxane ternary graft modifier, named EAS-GMA.

[0051] The preparation method of the core-shell structure composite modifier includes the following steps: Under nitrogen protection, isocyanate-terminated polyurethane prepolymer, epoxy resin (E-44), benzyl glycidyl ether, and DBTDL are reacted at a mass ratio of 55:40:3:0.3 at a temperature range of 60℃~65℃ and 250rpm for 2.5h to obtain the core liquid; by mass, 1.2 parts of SDS are added to 300 parts of deionized water and stirred at 300rpm to dissolve. 30 parts of the core liquid are added and emulsified at 11000rpm for 8min until the D90 is below 150μm to obtain the emulsion; 8 parts of MMA and 0.5 parts of KH are then added to the emulsion. After premixing with -570, it was added dropwise to the emulsion. The mixture was stirred at 55℃ and 300rpm for 30min for adsorption. Then, 0.4 parts of KPS (pre-diluted with 10 parts of deionized water) were added. The temperature was raised to 70℃~75℃ and stirred at 300rpm for 4h (to allow MMA to polymerize on the surface of the core droplet to form a PMMA shell, while KH-570 participated in the reaction to enhance interfacial bonding). The mixture was cooled to room temperature and centrifuged at 4000rpm for 15min. The precipitate was collected and washed three times with deionized water to remove residual SDS and KPS. The mixture was then vacuum dried at 45℃ for 14h and passed through a 200-mesh sieve to obtain the core-shell structure composite modifier.

[0052] The preparation method of the above-mentioned high-strength cold-applied asphalt patching material that can be pressed and solidified immediately includes the following steps:

[0053] S1: According to the formula, mix basalt manufactured sand, limestone rock chips and KH-550 evenly to obtain pre-activated aggregate;

[0054] S2: According to the formula, heat the road petroleum asphalt to 120°C, add EAS-GMA, mix evenly, cool to 80°C, add anionic emulsified asphalt and epoxidized soybean oil, mix evenly, and obtain the composite binder;

[0055] S3: Add pre-activated aggregate to the mixer and stir at room temperature for 1 minute; add composite binder and continue stirring for 3 minutes; add active filler and lignin fiber and continue stirring for 1 minute; add core-shell structure composite modifier and continue stirring for 2 minutes; finally add accelerator, anti-aging agent and anti-water loss agent and continue stirring for 3 minutes until the mixture is uniform and free of white spots, thus obtaining asphalt cold patching material.

[0056] Example 3

[0057] A high-strength cold-patch asphalt material that can be pressed and solidified immediately comprises the following raw materials in parts by weight: 10 parts road petroleum asphalt, 0.8 parts anionic emulsified asphalt, 2.5 parts EAS-GMA, 1.0 part core-shell structure composite modifier, 0.5 parts epoxidized soybean oil, 95 parts basalt manufactured sand, 45 parts limestone rock chips, 0.1 parts KH-550, 7 parts active filler, 0.2 parts lignin fiber, 0.6 parts accelerator, 0.1 part anti-aging agent, and 1.0 part water loss resistant agent. The road petroleum asphalt is 70# road petroleum asphalt; the water loss resistant agent is hydrated lime; the active filler includes limestone powder and silica fume in a mass ratio of 4:1.5; the accelerator includes triethyl citrate and nano-calcium carbonate in a mass ratio of 1:1.5; and the anti-aging agent includes antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1.2.

[0058] The preparation method of EAS-GMA includes the following steps: 55 parts by mass of polyamide resin (type 650) are added to 100 parts by xylene, and the mixture is refluxed and stirred at 110℃ and 400rpm for 20min to dissolve. The mixture is then cooled to 90℃, and 45 parts by mass of epoxy resin (type E-51) are added dropwise at a rate of 0.8mL / min. 0.4 parts by mass of stannous octoate are added, and the mixture is stirred at 400rpm for 3.0h in the temperature range of 85℃ to 90℃ to obtain epoxy-amide prepolymer. 3 parts by mass of KH-570 are added dropwise, and the mixture is heated to 110℃ and stirred at 400rpm for 1.5h. All xylene is recovered by vacuum distillation at 90℃, and the mixture is cooled to room temperature to obtain epoxy-amide-siloxane ternary graft modifier, named EAS-GMA.

[0059] The preparation method of the core-shell structure composite modifier includes the following steps: Under nitrogen protection, isocyanate-terminated polyurethane prepolymer, epoxy resin (E-44), benzyl glycidyl ether, and DBTDL are reacted at a mass ratio of 65:30:7:0.1 at 60℃~65℃ and stirred at 300rpm for 2h to obtain the core liquid; by mass, 1.8 parts of SDS are added to 200 parts of deionized water and stirred at 400rpm to dissolve. 40 parts of the core liquid are added and emulsified at 9000rpm for 12min until the D90 is below 150μm to obtain the emulsion; 5 parts of MMA and 1.0 parts of KH-5 are then reacted. After premixing with 70, the mixture was added dropwise to the emulsion. The mixture was stirred at 50°C and 400 rpm for 60 min to adsorb the contents. Then, 0.2 parts of KPS (pre-diluted with 12 parts of deionized water) were added. The mixture was heated to 70°C–75°C and stirred at 400 rpm for 3.5 h (to allow MMA to polymerize on the surface of the core droplet to form a PMMA shell, while KH-570 participates in the reaction to enhance interfacial bonding). The mixture was cooled to room temperature and centrifuged at 5000 rpm for 10 min. The precipitate was collected and washed four times with deionized water to remove residual SDS and KPS. The mixture was then vacuum dried at 50°C for 10 h and passed through a 250-mesh sieve to obtain the core-shell structure composite modifier.

[0060] The preparation method of the above-mentioned high-strength cold-applied asphalt patching material that can be pressed and solidified immediately includes the following steps:

[0061] S1: According to the formula, mix basalt manufactured sand, limestone rock chips and KH-550 evenly to obtain pre-activated aggregate;

[0062] S2: According to the formula, heat the road petroleum asphalt to 130℃, add EAS-GMA, mix evenly, reduce the temperature to 70℃, add anionic emulsified asphalt and epoxidized soybean oil, mix evenly, and obtain the composite binder;

[0063] S3: Add pre-activated aggregate to the mixer and stir at room temperature for 2 minutes; add composite binder and continue stirring for 2 minutes; add active filler and lignin fiber and continue stirring for 2 minutes; add core-shell structure composite modifier and continue stirring for 1 minute; finally add accelerator, anti-aging agent and anti-water loss agent and continue stirring for 5 minutes until the mixture is uniform and free of white spots, thus obtaining asphalt cold patching material.

[0064] Recommended application method for the asphalt cold patch material in the above embodiments: After cleaning the pothole to be repaired, fill it with asphalt cold patch material, slightly higher than the original road surface, and compact it with a plate compactor or small roller until the surface is flat and dense. After compaction, a small amount of water mist can be sprayed on the repair surface to promote the demulsification of the slow-cracking, fast-setting emulsified asphalt and the reaction of the components within the core-shell structure. Traffic can be opened immediately after compaction.

[0065] The raw material specifications and sources involved in the above embodiments are as follows: 70# road petroleum asphalt is from Foshan Nanhai Hongxian Municipal Engineering Co., Ltd.; anionic emulsified asphalt is distributed by Zibo Baigui Trade Co., Ltd., and manufactured by Qilu Petrochemical; epoxidized soybean oil is from Shandong Xinheng Chemical Co., Ltd.; basalt manufactured sand has a particle size range of 4-8 mesh and a moisture content ≤0.3%; limestone chips have a particle size range of 8-150 mesh and a moisture content ≤0.3%; KH-550 is 3-aminopropyltriethoxysilane, sourced from Wuhan Jiyesheng Chemical Co., Ltd.; limestone powder is from Shijiazhuang Jinming Mining Development Co., Ltd., 325 mesh desulfurized quicklime; silica fume is from Hebei Yousheng Refractory Materials Co., Ltd., sieved through a 200 mesh sieve; lignin fiber is from Changzhou Bochao Engineering Materials Co., Ltd.; triethyl citrate is from Hubei Shishun Biotechnology Co., Ltd.; and nano-calcium carbonate is from Forsmann Technology (Beijing) Co., Ltd., with a median particle size of 50nm-80nm. Antioxidant 1010 is sourced from Hubei Shishun Biotechnology Co., Ltd. UV absorber UV-531 is sourced from Hangzhou Jingyou Chemical Co., Ltd. Slaked lime is sourced from Wuhan Jiyesheng Chemical Co., Ltd., and passed through a 200-mesh sieve. Polyamide resin (type 650) is sourced from Hubei Xinmingtai Chemical Co., Ltd. Xylene purity is above 98%. Epoxy resin (type E-51) is sourced from Jinan Jingsheng Chemical Co., Ltd. Stannous octoate purity is above 98%. KH-570 is 3-methacryloyloxypropyltrimethoxysilane, sourced from Hubei Shishun Biotechnology Co., Ltd. Isocyanate-terminated polyurethane prepolymer is sourced from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., isocyanate-terminated prepolymer 103837-45-2 polyurethane prepolymer. Epoxy resin (E-44) is sourced from Jinan Jingsheng Chemical Co., Ltd. Benzyl glycidyl ether is sourced from Shaoguan Yang'an Chemical Co., Ltd. DBTDL is dibutyltin dilaurate, purity above 99%. SDS is sodium dodecyl sulfate, with a purity of over 99%. MMA is methyl methacrylate monomer, sourced from Shandong Shuojia Chemical Co., Ltd. KPS is potassium persulfate, with a purity of over 99%.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that the anionic emulsified asphalt in the cold patch is changed to 4.5 parts, and EAS-GMA and core-shell structure composite modifier are not added.

[0068] Comparative Example 2

[0069] The difference from Example 1 is that in the cold patching material, EAS-GMA is changed to 0.3 parts and the core-shell structure composite modifier is changed to 3.2 parts.

[0070] Comparative Example 3

[0071] The difference from Example 1 is that in the cold patching material, EAS-GMA is changed to 3.2 parts and the core-shell structure composite modifier is changed to 0.3 parts.

[0072] Comparative Example 4

[0073] The difference from Example 1 is that the accelerator in the cold-mixed material is entirely nano-calcium carbonate.

[0074] Comparative Example 5

[0075] The difference from Example 1 is that epoxy resin (E-51 type) is not added in the preparation of EAS-GMA, that is, the step of "adding 40 parts of epoxy resin (E-51 type) at a rate of 0.9 mL / min, adding 0.5 parts of stannous octoate, stirring at 350 rpm for 2.5 h in the temperature range of 85℃~90℃ to obtain epoxy-amide prepolymer" is omitted.

[0076] Comparative Example 6

[0077] The difference from Example 1 is that the step of "adding 4 parts of KH-570 dropwise, heating to 105°C, and stirring at 350 rpm for 1.5 h" is omitted in the preparation of EAS-GMA.

[0078] Comparative Example 7

[0079] The difference from Example 1 is that in the preparation of the core-shell structure composite modifier, the mass ratio of terminal isocyanate polyurethane prepolymer, epoxy resin (E-44), benzyl glycidyl ether, and DBTDL is changed to 35:60:5:0.2; and KH-570 is not added.

[0080] I. Initial compressive strength at room temperature:

[0081] Specimen preparation: Following JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0702 (compaction method), each side was compacted 75 times to form cylindrical specimens with a diameter of 101.6 mm × 63.5 mm. Five valid parallel specimens were prepared for each group. The specimens were tested immediately after being allowed to stand at room temperature (25℃) for 5 minutes.

[0082] Test method: Place the specimen in the center of the pressure plate of the compression testing machine and continuously load it at a loading rate of 1 mm / min until failure. Record the maximum load (N). Compressive strength Rc (MPa) = maximum load / specimen cross-sectional area. Take the average value.

[0083] II. Long-term compressive strength development:

[0084] Sample preparation: Same as "I. Initial compressive strength at room temperature" sample, with 5 effective parallel samples per group.

[0085] Curing and Testing: After molding, the specimens were cured for 7 days under standard curing conditions (temperature 23±2℃, relative humidity 50±5%). The compressive strength was tested according to the method described in "I. Initial Compressive Strength at Room Temperature". The average value was taken.

[0086] III. Interlayer bond strength:

[0087] Specimen preparation: C50 grade cement concrete was used as the matrix (100mm × 50mm). After cleaning and drying the matrix surface, loose cold-mixed material was filled in and compacted 50 times on each side using a Marshall compactor to achieve a compacted layer thickness of 20±2mm, forming a composite specimen. Five valid parallel specimens were prepared for each group.

[0088] Testing method: 24 hours after molding, a Φ50mm steel pull-out head was vertically bonded to the center of the cold-applied filler layer surface using high-strength epoxy structural adhesive. After curing for 24 hours under standard conditions (temperature 23±2℃, relative humidity 50±5%), a pull-out tester was used to apply a uniform displacement rate of 50mm / min until interface failure. Bond strength (MPa) = maximum load / pull-out head area. The average value was taken.

[0089] IV. Residual stability after immersion in water:

[0090] Specimen preparation: Marshall specimens were formed by compaction of both sides 75 times according to JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0702 (compaction method). The specimens were cured for 72 hours under standard conditions (temperature 23±2℃, relative humidity 50±5%) before testing. Six valid parallel specimens were prepared for each group.

[0091] Test method: According to JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0709 (Marshall Stability Test of Asphalt Mixtures), the specimens were divided into two groups, A and B, with three specimens in each group. Group A: The stability MS was measured after being kept in a constant temperature water bath at 60℃ for 30 min. Group B: The stability MS1 was measured after being kept in a constant temperature water bath at 60℃ for 48 h. Residual stability MS0 (%) after immersion = (MS1 / MS) × 100%. The average value was taken.

[0092] V. Freeze-thaw splitting strength ratio:

[0093] Sample preparation: Cylindrical specimens were formed by compaction of both sides 50 times according to JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0702 (compaction method). Six valid parallel specimens were prepared for each group.

[0094] Test method: According to JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0729 (Freeze-thaw Splitting Test of Asphalt Mixtures), valid specimens were randomly divided into a control group and a freeze-thaw group, with 3 specimens in each group. The control group specimens were directly tested for splitting strength R1. The freeze-thaw group specimens underwent one cycle of vacuum saturation (vacuum degree 97.3 kPa, maintained for 15 min), freezing at -20℃ for 16 h, and immersion in a 60℃ water bath for 24 h, and then the splitting strength R2 was tested. The freeze-thaw splitting strength ratio (TSR) (%) = (R2 / R1) × 100%. The average value was taken.

[0095] VI. Anti-aging properties:

[0096] Sample preparation: Following JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", cylindrical specimens were formed by compacting both sides 75 times each using the T 0702 (compaction method) method. The specimens were then cured for 7 days under standard curing conditions (temperature 23±2℃, relative humidity 50±5%). Six valid parallel specimens were prepared for each group; three were aged, and the other three served as a control group for direct testing of unaged compressive strength.

[0097] Aging method: After curing, the specimens were placed in a short-term aging oven and aged at 135℃ for 4 hours, and then placed in a long-term aging oven and aged at 85℃ for 120 hours.

[0098] Performance testing and retention rate calculation: After aging, the specimens are compared with the test results of the control group according to "I. Initial compressive strength at room temperature". The performance retention rate (%) is calculated as follows: (Performance value after aging / Performance value before aging) × 100%. The average value is taken.

[0099] Table 1. Test Results (Average Values)

[0100]

[0101] The cold patching materials in Examples 1 to 3 are multi-component synergistically constructed integrated systems of physical curing, chemical curing, and interface strengthening, achieving immediate curing and high strength and durability upon compaction. EAS-GMA provides immediate strengthening and adhesion; the epoxy-amide prepolymer reacts with the asphalt active components through physical entanglement, rapidly increasing the binder viscosity and cohesion, laying the foundation for initial strength. Siloxane groups hydrolyze and condense with hydroxyl groups on the aggregate surface to form -Si-O- chemical bonds, while self-crosslinking forms micro-crosslinking points, solving the problem of loosening and peeling in traditional cold patching materials. The core-shell structure composite modifier provides long-term strengthening; the core is encased in a PMMA shell in a dormant state. Upon compaction, the shell ruptures, and the -NCO groups in the core chemically crosslink with water and epoxy groups, becoming the main source of long-term strength. The PMMA shell also protects the core, improves interfacial compatibility, and, as micron-sized reinforcing particles, directly improves resistance to deformation. Triethyl citrate accelerates the demulsification of emulsified asphalt and epoxy curing, while nano-calcium carbonate adsorbs asphalt components through its high specific surface area and acts as a crystallization nucleus. The combination of the two achieves a precise match between curing rate and strength formation. Components such as active filler, KH-550, and epoxidized soybean oil synergistically optimize the aggregate-asphalt interface, fill micropores, improve flexibility, resist water erosion and aging, and jointly construct a stable mixture system.

[0102] Comparative Example 1 contained no EAS-GMA, no core-shell modifier, and excessive emulsified asphalt. The system degenerated into a traditional single emulsified asphalt cold patch mix, lacking the physical crosslinking and strong adhesion of EAS-GMA, as well as the chemical curing mechanism of the core-shell modifier. Its strength depended entirely on the physical bonding and aggregate adsorption after the emulsified asphalt demulsified, a slow process with a low upper limit of strength. There was no chemical bonding at the interface, making it susceptible to water and freeze-thaw cycles, resulting in comprehensive deterioration of adhesion, water stability, and aging resistance. All performance indicators were at a low level.

[0103] In Comparative Example 2, there was insufficient EAS-GMA and excessive core-shell structure. Insufficient EAS-GMA led to a decrease in initial adhesion and chemical bonding ability at the aggregate interface, making it impossible to form a complete physical reinforcement network. In the case of excessive core-shell modifier, the rigid PMMA particles hindered the tight interlocking of aggregates in the initial stage, slightly reducing the initial density. Moreover, the simultaneous reaction of a large number of cores easily generated internal stress, resulting in low initial strength and interlayer bond strength. Although the long-term strength still developed due to the large amount of cured components, the water stability and anti-aging properties were weakened due to insufficient interface protection.

[0104] In Comparative Example 3, there was an excess of EAS-GMA and an insufficient core-shell structure. The excess EAS-GMA resulted in a higher initial viscosity of the binder, affecting workability and initial compaction. Although the initial bond strength was slightly improved, the insufficient core-shell structure led to fewer chemical curing reaction points, resulting in a lack of momentum for long-term strength development. The overall strength relied on the properties of the asphalt itself, and the upper limit of strength was reduced. At the same time, the system was too rigid and lacked flexibility, resulting in a decrease in high-temperature deformation resistance and freeze-thaw stability, and low freeze-thaw splitting strength.

[0105] In Comparative Example 4, the accelerator was solely nano-calcium carbonate. Nano-calcium carbonate can only provide early support through physical filling and adsorption, but it cannot accelerate the demulsification of emulsified asphalt and the ring-opening of epoxy groups. This results in a prolonged curing cycle, slow initial strength formation, and an inability to achieve good immediate curing upon pressing. Furthermore, the lack of an organic accelerator leads to insufficient chemical crosslinking density, resulting in low long-term strength and interlayer bond strength. Additionally, the poor compatibility between organic and inorganic components makes component separation prone to occur, affecting long-term stability.

[0106] In Comparative Example 5, EAS-GMA was not epoxy-grafted. After losing the epoxy groups, EAS-GMA only retained the adhesive properties of amides and the coupling properties of siloxanes, and could not form a strong chemical cross-linking network with asphalt and core-shell modifiers, thus greatly reducing the toughening and strengthening effect; the overall modulus of the system decreased, and the strength and high-temperature stability also decreased; the interfacial bonding strength was insufficient, and the water stability and anti-aging properties were impaired due to the weak structure.

[0107] In Comparative Example 6, EAS-GMA was not grafted with siloxane. The absence of siloxane groups prevented EAS-GMA from forming chemical bonds with the aggregates. It could only rely on the physical adhesion and limited polarity of the epoxy-amide resin to bond the aggregates, resulting in a fundamental weakening of interfacial adhesion and a significant decrease in interlayer bond strength. Water easily penetrated and damaged the fragile physical bonding interface, leading to a significant reduction in water immersion residual stability and freeze-thaw splitting strength ratio. Other properties also declined overall due to the interface weakness.

[0108] In Comparative Example 7, the core-shell structure ratio was changed, and KH-570 was omitted. The epoxy resin proportion in the core exceeded that of the polyurethane prepolymer, leading to a more rigid and brittle core after curing, and a decrease in flexibility. An excessively high epoxy resin content directly reduces the relative content of terminal isocyanate (-NCO) groups in the core, thereby weakening the cross-linking reaction between the polyurethane prepolymer and epoxy resin. This results in insufficient cross-linking density and decreased compatibility in the core structure, ultimately leading to a deterioration in the modification effect. The absence of KH-570 worsened the interfacial compatibility between the PMMA shell and the asphalt and EAS-GMA phases, making the core-shell particles prone to agglomeration, becoming a system defect. This not only affected the compaction effect, leading to insufficient initial strength, but also caused the brittle core and weak interface to fail under high-temperature shear, resulting in a comprehensive deterioration of long-term strength, high-temperature stability, and adhesion.

Claims

1. A high-strength cold-patch asphalt material that can be pressed and solidified immediately, characterized in that, The raw materials include the following parts by weight: 7-10 parts road petroleum asphalt, 0.8-1.2 parts anionic emulsified asphalt, 1.5-2.5 parts EAS-GMA, 1.0-2.0 parts core-shell structure composite modifier, 0.3-0.5 parts epoxidized soybean oil, 95-105 parts basalt manufactured sand, 35-45 parts limestone chips, 0.1-0.2 parts KH-550, 5-7 parts active filler, 0.2-0.3 parts lignin fiber, 0.3-0.6 parts coagulant accelerator, 0.1-0.2 parts anti-aging agent, and 0.5-1.0 parts water loss resistant agent; The EAS-GMA is obtained by reacting polyamide resin, epoxy resin, and stannous octoate in xylene at a mass ratio of (45-55):(35-45):(0.4-0.6) to obtain an epoxy-amide prepolymer, which is then modified with KH-570 and obtained by vacuum distillation. The core-shell structure composite modifier is prepared by reacting isocyanate-terminated polyurethane prepolymer, epoxy resin, benzyl glycidyl ether, and DBTDL in a mass ratio of (55-65):(30-40):(3-7):(0.1-0.3) to obtain the core liquid; then the core liquid is emulsified in deionized water containing SDS, and MMA and KH-570 are added for adsorption, and KPS is used to initiate the reaction. The product is then obtained by centrifugation, washing, vacuum drying, and sieving.

2. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 1, characterized in that, The road petroleum asphalt is 70# road petroleum asphalt; the water-resistant agent is slaked lime.

3. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 1, characterized in that, The active filler comprises limestone powder and silica fume in a mass ratio of (4-6):(1-1.5); the coagulant comprises triethyl citrate and nano-calcium carbonate in a mass ratio of 1:(1.5-2); and the anti-aging agent comprises antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:(0.8-1.2).

4. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 1, characterized in that, The preparation method of EAS-GMA includes the following steps: by mass, 45 to 55 parts of polyamide resin are added to 100 to 120 parts of xylene, stirred and dissolved, 35 to 45 parts of epoxy resin are added dropwise, 0.4 to 0.6 parts of stannous octoate are added, and the mixture is stirred and reacted in a temperature range of 85°C to 90°C to obtain an epoxy-amide prepolymer. 3 to 5 parts of KH-570 are added dropwise, and the reaction is continued at 100°C to 110°C. The mixture is then distilled under reduced pressure to obtain EAS-GMA.

5. The high-strength cold patching material for asphalt that can be pressed and solidified immediately according to claim 4, characterized in that, The stirring and dissolving process is carried out at 100℃~110℃, and then cooled to 85℃~90℃; the stirring reaction time is 2.5h~3.0h; the continued reaction time is 1.5h~2h; and the vacuum distillation is carried out to recover all xylene.

6. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 1, characterized in that, The preparation method of the core-shell structure composite modifier includes the following steps: Under nitrogen protection, isocyanate-terminated polyurethane prepolymer, epoxy resin, benzyl glycidyl ether, and DBTDL are reacted by stirring at a mass ratio of (55-65):(30-40):(3-7):(0.1-0.3) to obtain a core liquid; 1.2-1.8 parts by mass of SDS are added to 200-300 parts by mass of deionized water and stirred to dissolve, 30-40 parts by mass of the core liquid are added and emulsified to obtain an emulsion; 5-8 parts by mass of MMA and 0.5-1.0 parts by mass of KH-570 are premixed and added dropwise to the emulsion, stirred and adsorbed, 0.2-0.4 parts by mass of KPS are added, and the mixture is stirred and reacted at 70-75℃ for 3.5-4 hours. After cooling to room temperature, the mixture is centrifuged, the precipitate is collected, washed, vacuum dried, and sieved to obtain the core-shell structure composite modifier.

7. The high-strength cold patching material for asphalt that can be pressed and solidified immediately according to claim 6, characterized in that, The core liquid is prepared by stirring at 60℃~65℃ for 2h~2.5h.

8. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 6, characterized in that, The emulsification is carried out at 9000 rpm to 11000 rpm for 8 min to 12 min until the D90 is below 150 μm; the stirring adsorption is carried out at 50℃ to 55℃ for 30 min to 60 min.

9. The high-strength cold-patch asphalt material that can be pressed and solidified immediately according to claim 6, characterized in that, The KPS is pre-diluted with 10 to 12 parts of deionized water before being added; the centrifugation is performed at 4000 to 5000 rpm for 10 to 15 minutes; the washing is performed with deionized water; the vacuum drying is performed at 45°C to 50°C and -0.07 MPa to -0.08 MPa for 10 to 14 hours; and the sieve mesh size is 200 to 250 mesh.

10. The method for preparing a high-strength cold-applied asphalt patching material that can be pressed and solidified immediately according to claim 1, characterized in that, Includes the following steps: S1: According to the formula, basalt manufactured sand, limestone rock chips and KH-550 are mixed evenly to obtain pre-activated aggregate; S2: According to the formula, heat the road petroleum asphalt to 120℃~130℃, add EAS-GMA, mix evenly, cool to 70℃~80℃, add anionic emulsified asphalt and epoxidized soybean oil, mix evenly, and obtain composite binder; S3: Add pre-activated aggregate to the mixer and stir at room temperature; add composite binder and stir; add active filler and lignin fiber and stir; add core-shell structure composite modifier and stir; finally add accelerator, anti-aging agent and anti-water loss agent and stir evenly to obtain asphalt cold patching material.

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