Composite sealing method for enhancing durability of asphalt pavement of high and cold road

Abstract

The invention belongs to the technical field of asphalt pavement construction, and discloses a high and cold road asphalt pavement durability enhanced composite sealing method which comprises the following steps: S1, original pavement treatment and disease repair; s2, construction of a bonding layer; s3, construction of an anti-crack waterproof layer; s4, wearing layer construction; s5, performing quality detection and acceptance; and S6, environment adaptability adjustment. According to the invention, through inhibition of reflection crack propagation and composite design of a gravel seal three-dimensional interlocking framework and a micro-surfacing dense structure, the load distribution capability and anti-slide performance are enhanced, the track deformation risk is reduced, and an interlayer bonding system recovers the activity of old asphalt and strengthens the interface bonding strength through the dual effects of permeation regeneration and mechanical interlocking; and by means of construction process dynamic monitoring and a low-temperature adaptability adjusting mechanism, stable matching of material performance and process parameters in an extreme environment is guaranteed, and balance of rapid forming and long-acting protection is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt pavement construction, and specifically relates to a method for enhancing the durability of composite seal coats for asphalt pavements on alpine highways. Background Art

[0002] The composite seal coat method for asphalt pavements on alpine highways is a maintenance technology designed for highway pavements in cold regions, aiming to improve the durability, crack resistance, and skid resistance of the pavement. Due to the extremely cold climate and drastic temperature changes in alpine regions, asphalt pavements are prone to problems such as cracks and spalling, which affect the service life and safety of the road. The composite seal coat method forms a protective layer with excellent crack resistance by applying one or more layers of special seal coat materials on the original asphalt pavement. The seal coat materials are generally made of modified asphalt, polymers, fibers, or other high-performance materials to enhance their adaptability to temperature changes and improve the rutting resistance and water damage resistance of the pavement.

[0003] However, the extremely low temperatures (such as below -20°C) and frequent freeze-thaw cycles in alpine regions pose strict requirements on the performance of asphalt materials. Existing composite seal coat materials (such as ordinary emulsified asphalt or conventional modified asphalt) are prone to brittle fracture and creep deformation at low temperatures. Modified asphalt has poor fracture toughness at low temperatures and is prone to cracking due to temperature shrinkage stress. At the same time, insufficient low-temperature bending creep performance will cause irreversible deformation of the pavement under repeated frost heaving and vehicle loads, accelerating the loosening and peeling of the seal coat. Although some technologies use SBS modified asphalt or fiber-reinforced materials, the compatibility problem between the materials and the matrix asphalt still exists generally, resulting in uneven dispersion at low temperatures and difficulty in forming a stable crack-resistant structure.

[0004] The composite seal coat consists of multiple layers such as a chip seal and microsurfacing. However, in the alpine environment, the permeability and bonding strength of the interlayer bonding material are insufficient, which is prone to structural disconnection. When ordinary emulsified asphalt is used as the bonding layer, the demulsification speed is too fast at low temperatures, and it is difficult to penetrate into the cracks of the base layer to form an effective anchorage. The residual moisture between layers further weakens the bonding force after freeze-thaw. Shear cracks on the alpine highway pavement mostly originate from the interlayer shear stress exceeding the material limit. Especially in the braking areas of heavy vehicles, the seal coat is prone to slip and peel off after debonding from the base layer. In addition, in traditional chip seal construction, if high-polymer modified emulsified asphalt or special brushing equipment is not used, the interlocking density of the chips and asphalt is insufficient, and an anti-shear skeleton cannot be formed, increasing the risk of interlayer shear failure. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for enhancing the durability of composite seal coats for asphalt pavements on alpine highways to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A method for enhancing the durability of composite seal coats for asphalt pavements on alpine highways, comprising the following steps: S1: Original pavement treatment and disease repair; S2: Bonding layer construction; S3: Crack-resistant waterproof layer construction; S4: Wearing course construction; S5: Quality inspection and acceptance; S6: Environmental adaptability adjustment; The original pavement treatment and disease repair include milling and cleaning, crack and pothole repair. The bonding layer construction includes material selection and spraying, synchronous fiber reinforcement. The crack-resistant waterproof layer construction includes synchronous construction of chip seal, rolling and compaction. The wearing course construction includes preparation of micro-surfacing mixture, paving and curing. The quality inspection and acceptance include verification of material properties, monitoring of construction process. The environmental adaptability adjustment includes optimization of low-temperature construction, supplementary measures in plateau areas.

[0007] As a further technical solution of the present invention, the milling and cleaning include using a fine milling machine to perform depth-controlled milling on the original pavement, with a milling depth of 3 mm to 5 mm, a cutter spacing not exceeding 8 mm, and the texture depth after milling needs to reach more than 0.6 mm. The surface residual debris is washed with a high-pressure water gun to ensure no floating dust, oil stain and loose particles, and the moisture content is lower than 2%. The crack and pothole repair include for cracks with a width ≥ 2 mm, using epoxy resin grouting adhesive for perfusion, with a grouting pressure of 0.3 MPa to 0.5 MPa, a curing time ≤ 2 hours, a tensile strength ≥ 5 Mpa. Local potholes are filled with cold patch material, and 3% to 5% of rubber powder is incorporated into the cold patch material, with a compaction degree ≥ 95% and a flatness error ≤ 3 mm.

[0008] As a further technical solution of the present invention, the material selection and spraying include using SBS high-elastic modified emulsified asphalt for the bonding layer, with a softening point ≥ 85°C, a 5°C ductility ≥ 35 cm, a demulsification time ≤ 30 seconds, and a penetration depth ≥ 5 mm. The parameters of the spraying equipment are an asphalt temperature of 60°C to 70°C, a spraying amount of 1.2 kg / m² to 1.5 kg / m², a lateral overlap width ≤ 10 cm, and a longitudinal overlap error ≤ 5 cm. The synchronous fiber reinforcement includes evenly spreading basalt chopped fibers within 30 seconds after the emulsified asphalt is sprayed, with a fiber length of 60 mm, a diameter of 7 μm, a spreading amount of 80 g / m² to 100 g / m², and a coverage rate ≥ 95%.

[0009] As a further technical solution of the present invention, for the synchronous construction of the chip seal, the selected chips are 5 mm to 8 mm basalt chips, with a crushing value ≤ 15%, a water absorption rate ≤ 1%, a spreading amount of 8 kg / m² to 10 kg / m², a coverage rate ≥ 85%, and SBS modified asphalt is synchronously sprayed, with the asphalt temperature being 130°C to 150°C, a viscosity ≥ 2000 Pa·s, and the embedding depth of the chips ≥ 2 / 3 of the particle size. For the rolling and compaction, a pneumatic tired roller above 26 t is used for rolling, the initial rolling temperature ≥ 130°C, the rolling speed is 2 km / h to 3 km / h, the number of rolling passes is 2, and the void ratio ≤ 8%.

[0010] As a further technical solution of the present invention, for the preparation of the micro-surfacing mixture, the aggregate gradation is AC-10 gap-graded, the passing rate of the 4.75 mm sieve hole is 45% to 55%, the cement content of the filler is 1.5% to 2.0%, the residue content of the SBS modified emulsified asphalt ≥ 65%, the mixing time ≤ 30 seconds, and the discharge temperature is 10°C to 30°C. For the paving and curing, the paving thickness is 10 mm to 12 mm, the paving speed is 4 m / min to 6 m / min, and immediately after paving, it is statically rolled once with an 8 t double steel wheel roller, the final rolling temperature ≥ 80°C, the natural curing time ≥ 4 hours, and when the ambient temperature is lower than 5°C, a hot air blanket is used to assist in heating up, and the vehicle speed limit during the initial stage of opening to traffic ≤ 40 km / h.

[0011] As a further technical solution of the present invention, for the verification of the material properties, for each batch of SBS modified asphalt, the test indexes include softening point, ductility at 5°C, and freeze-thaw splitting strength ratio ≥ 80%. For the chips, the test indexes include Los Angeles abrasion value ≤ 20% and adhesion grade ≥ 4 levels.

[0012] As a further technical solution of the present invention, for the monitoring of the construction process, the interlayer bond strength is sampled and inspected once every 500 m², the pull-out strength ≥ 0.8 MPa, the shear strength at -20°C ≥ 0.6 Mpa, the sampling frequency of the permeability coefficient is once every 100 m, and the requirement is ≤ 50 mL / min, and the skid resistance pendulum value BPN ≥ 55.

[0013] As a further technical solution of the present invention, for the optimization of low-temperature construction, when the ambient temperature is lower than 0°C, 2% to 3% of a low-temperature demulsifier is added to the emulsified asphalt of the bonding layer, the spraying temperature is increased to 65°C to 75°C, and 0.3% to 0.5% of a Sasobit® warm mix agent is incorporated into the micro-surfacing mixture, reducing the construction temperature to 5°C to 10°C.

[0014] As a further technical solution of the present invention, for the supplementary measures in plateau areas, in areas with strong ultraviolet radiation, 1% to 2% of nano-TiO2 anti-aging agent is added to the wearing course to improve the weather resistance of the asphalt.

[0015] The beneficial effects of the present invention are as follows: (1) Through material modification synergism and process innovation, the present invention significantly improves the life-cycle performance of alpine highway pavements. The synergistic effect of highly elastic modified emulsified asphalt and fiber reinforcement forms a flexible anti-cracking interface, effectively absorbing low-temperature shrinkage stress and blocking the penetration of freeze-thaw moisture, inhibiting the propagation of reflective cracks. The composite design of the three-dimensional interlocking skeleton of the chip seal and the dense structure of the micro-surfacing enhances the load distribution capacity and anti-skid performance, reducing the risk of rutting deformation. The interlayer bonding system restores the activity of the old asphalt and strengthens the interface bonding strength through the dual effects of infiltration regeneration and mechanical interlocking, avoiding shear slip failure caused by interlayer debonding. The dynamic monitoring during the construction process and the low-temperature adaptability adjustment mechanism ensure the stable matching of material properties and process parameters in extreme environments, achieving the balance between rapid forming and long-term protection.

[0016] (2) By constructing multiple protection barriers targeting the characteristics of the alpine environment, the present invention greatly improves the environmental adaptability and functional durability of the pavement. The combination of nano anti-aging agents and warm mix technology delays the breakage of asphalt molecular chains and low-temperature embrittlement caused by ultraviolet irradiation, maintaining the continuity and elastic recovery ability of the seal layer structure. The composite effect of the fiber reinforcement network and the modified asphalt disperses dynamic load impacts and improves the anti-fatigue performance, inhibiting the structural looseness caused by repeated frost heaving. The closed waterproof layer and the water seepage monitoring and control form a three-dimensional protection, blocking the water migration path and reducing the erosion damage of the freeze-thaw cycle to the base layer. The overall technology realizes the integrated improvement of anti-cracking, waterproofing, anti-skid and noise reduction functions through the synergistic optimization of materials-structures-processes. Brief Description of the Drawings

[0017] Figure 1 is a schematic diagram of the overall process of the present invention; Figure 2 is a schematic diagram of the process of the original pavement treatment and disease repair of the present invention; Figure 3 is a schematic diagram of the process of the bonding layer construction of the present invention; Figure 4 is a schematic diagram of the process of the anti-cracking waterproof layer construction of the present invention; Figure 5 is a schematic diagram of the process of the wearing course construction of the present invention; Figure 6 is a schematic diagram of the process of the quality inspection and acceptance of the present invention; Figure 7 is a schematic diagram of the process of the environmental adaptability adjustment of the present invention. Detailed Description of the Invention

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] As Figures 1 to 7 shown, in the embodiment of the present invention, the method for enhancing the durability of the asphalt pavement of alpine highways includes the following steps: S1: Treatment of the original pavement and repair of diseases; S2: Construction of the bonding layer; S3: Construction of the crack-resistant waterproof layer; S4: Construction of the wearing course; S5: Quality inspection and acceptance; S6: Environmental adaptability adjustment; The treatment of the original pavement and repair of diseases include milling and cleaning, and repair of cracks and potholes. The construction of the bonding layer includes material selection and spraying, and synchronous fiber reinforcement. The construction of the crack-resistant waterproof layer includes synchronous construction of the chip seal, rolling and compaction. The construction of the wearing course includes preparation of the micro-surfacing mixture, paving and curing. The quality inspection and acceptance include verification of material properties and monitoring of the construction process. The environmental adaptability adjustment includes optimization of low-temperature construction and supplementary measures in plateau areas.

[0020] The comprehensive performance of the asphalt pavement of alpine highways is significantly improved through the multi-layer synergistic effect. The use of highly elastic modified asphalt and fiber toughening technology realizes the deep penetration and regeneration repair of the cracks in the original pavement by the bonding layer, forming a continuous crack-resistant interface. The crack-resistant waterproof layer inhibits the transmission of thermal contraction stress and blocks the erosion of freeze-thaw water through the interlocking and compact structure of the modified asphalt and single-sized aggregates. The wearing course combines the gap-graded and mineral composite fiber reinforcement process to improve the surface anti-skid performance and low-temperature anti-fatigue ability. The dynamic temperature control and anti-ultraviolet measures during construction ensure the stability of materials under extreme temperature differences and strong radiation conditions, forming a full-section closed protection system. The systematic quality monitoring and interlayer bonding strengthening process ensure the integrity and durability of the structure, effectively extending the service life of the pavement and reducing the maintenance cost in the whole life cycle.

[0021] As Figure 2As shown in the figure, milling and cleaning include using a fine milling machine to perform depth-controlled milling on the original road surface. The milling depth is 3 mm to 5 mm, the cutter spacing does not exceed 8 mm, and the texture depth after milling needs to reach more than 0.6 mm. Use a high-pressure water gun to wash the residual debris on the surface to ensure no floating dust, oil stains, and loose particles, with a moisture content lower than 2%. Crack and pothole repair include for cracks with a width ≥ 2 mm, using epoxy resin grouting adhesive for perfusion, with a grouting pressure of 0.3 MPa to 0.5 MPa, a curing time ≤ 2 hours, a tensile strength ≥ 5 Mpa. Locally potholes are filled with cold patch material, and 3% to 5% of rubber powder is incorporated into the cold patch material, with a compaction degree ≥ 95% and a flatness error ≤ 3 mm.

[0022] Through the refined milling and cleaning technology, the road surface flatness is effectively restored and the surface anti-skid performance is enhanced, providing a uniform and stable base surface for subsequent repairs. The milling depth control is combined with the high-pressure cleaning process to thoroughly remove loose particles and pollutants, improve the bonding force between the new and old material layers, and prevent interface peeling. The crack repair uses a high-permeability grouting material to seal the internal voids, block the intrusion of moisture, and inhibit the erosion and damage of the base layer caused by freeze-thaw cycles; the pothole filling is achieved through elastic modified cold patch material to achieve rapid compaction and durable reinforcement, reducing the risk of secondary cracking caused by temperature shrinkage. The overall process strengthens the structural continuity and load transfer efficiency of the road surface, significantly improves the rutting resistance, crack resistance, and waterproof performance in the alpine environment, extends the stability of the entire life cycle of the road, and ensures the driving safety and comfort.

[0023] As Figure 3 shown in the figure, material selection and spraying include using SBS high-elastic modified emulsified asphalt for the bonding layer, with a softening point ≥ 85°C, a ductility at 5°C ≥ 35 cm, a demulsification time ≤ 30 seconds, and a penetration depth ≥ 5 mm. The parameters of the spraying equipment are an asphalt temperature of 60°C to 70°C, a spraying amount of 1.2 kg / m² to 1.5 kg / m², a lateral lap width ≤ 10 cm, and a longitudinal overlap error ≤ 5 cm. Synchronous fiber reinforcement includes evenly spreading basalt chopped fibers within 30 seconds after the emulsified asphalt is sprayed. The fiber length is 60 mm, the diameter is 7 μm, the spreading amount is 80 g / m² to 100 g / m², and the coverage rate ≥ 95%.

[0024] Through the synergistic effect of highly elastic modified asphalt and fibers, the adaptability of the bonding layer to the original road surface is significantly improved. The high softening point asphalt combines with the deep penetration characteristics to effectively seal the micro-cracks in the base course and restore the activity of the aged asphalt, forming a continuous interface with shear resistance and fatigue resistance; precise temperature-controlled spraying ensures uniform coverage of the material, enhancing the interlayer bonding strength and waterproof sealing performance. The synchronous fiber spreading process forms a three-dimensional network reinforcement structure before the asphalt demulsifies, dispersing the temperature stress and inhibiting the propagation of reflection cracks, and enhancing the anti-deformation ability under dynamic loads. The composite effect of fibers and asphalt blocks the moisture migration path, reducing the risk of damage to the interlayer structure caused by freeze-thaw cycles, and achieving long-term anti-stripping and overall stability. The process as a whole strengthens the toughness and durability of the sealing layer system, providing reliable crack resistance protection and dynamic load adaptability for alpine highways.

[0025] As Figure 4 shown, the synchronous construction of the chip seal includes selecting 5mm to 8mm basalt chips for the chips, with a crushing value ≤ 15% and a water absorption rate ≤ 1%, a spreading amount of 8 kg / m² to 10 kg / m², a coverage rate ≥ 85%, synchronously spraying SBS modified asphalt, with the asphalt temperature of 130°C to 150°C, a viscosity ≥ 2000 Pa·s, the embedding depth of the chips ≥ 2 / 3 of the particle size, and the rolling and compaction including rolling with a rubber-tyred roller of more than 26 t, the initial rolling temperature ≥ 130°C, a rolling speed of 2 km / h to 3 km / h, 2 rolling passes, and a void ratio ≤ 8%.

[0026] Through the synchronous interlocking structure and high-temperature film-forming bonding technology, the comprehensive protection efficiency of the sealing layer system is significantly improved. The basalt chips and the modified asphalt form a three-dimensional interlocking skeleton at high temperatures, effectively dispersing the vehicle load stress and blocking the erosion of the freeze-thaw moisture to the base course, preventing the occurrence of crack propagation and loosening diseases. The directional rolling of the rubber-tyred roller promotes the deep embedding of the chips into the asphalt film, forming a dense waterproof barrier and enhancing the interlayer shear resistance and rutting resistance. The process as a whole constructs a composite functional layer with both flexibility and stiffness, improving the anti-skid performance of the road surface and the driving comfort, achieving the synergistic protection effect of long-term anti-seepage, anti-low-temperature shrinkage and dynamic load adaptability in alpine environments, and extending the service life of the road.

[0027] As Figure 5 shown, the preparation of the micro-surfacing mixture includes an aggregate gradation of AC-10 discontinuous gradation, the passing rate of the 4.75 mm sieve hole is 45% to 55%, the cement content of the filler is 1.5% to 2.0%, the residue content of the SBS modified emulsified asphalt ≥ 65%, the mixing time ≤ 30 seconds, the discharge temperature is 10°C to 30°C, the paving and curing include a paving thickness of 10 mm to 12 mm, a paving speed of 4 m / min to 6 m / min, immediately statically rolling 1 pass with an 8 t double-drum roller after paving, the final rolling temperature ≥ 80°C, the natural curing time ≥ 4 hours, using a hot air blanket to assist in heating when the ambient temperature is lower than 5°C, and the vehicle speed limit during the initial stage of opening to traffic ≤ 40 km / h.

[0028] Through material modification, gradation optimization and process coordination, the comprehensive protection efficiency of the micro-surfacing wearing course is significantly improved. The gap-graded design forms a framework dense structure, enhancing rutting resistance and skid resistance; the high-residue modified emulsified asphalt combined with fiber toughening technology forms a flexible anti-cracking interface to block the penetration of freeze-thaw moisture. The synchronous temperature-controlled paving process ensures the uniform distribution and rapid forming of the mixture, and the rubber-tyred rolling strengthens the embedding depth of the crushed stones to construct a continuous waterproof barrier. The hot air-assisted curing measure under low-temperature environment maintains the activity of the material, accelerates the strength formation and inhibits the temperature shrinkage cracks. The overall process achieves the balance between rapid traffic opening and long-term protection, improves the adaptability of the road surface in alpine regions to dynamic loads and anti-fatigue ability, and effectively delays the propagation of reflective cracks and surface loose spalling.

[0029] As Figure 6 shown, the verification of material properties includes the detection indexes of SBS modified asphalt for each batch, softening point, ductility at 5°C, freeze-thaw splitting strength ratio ≥ 80%, the detection indexes of crushed stones, Los Angeles abrasion value ≤ 20%, adhesion grade ≥ 4 levels. The construction process monitoring includes spot-checking the interlayer bonding strength once every 500 m², pull-out strength ≥ 0.8 MPa, shear strength at -20°C ≥ 0.6 Mpa, the spot-checking frequency of the water permeability coefficient is once every 100 m, and the requirement is ≤ 50 mL / min, skid resistance pendulum value BPN ≥ 55.

[0030] Through systematic quality control, the overall service performance of the sealing layer structure of alpine highways is significantly improved. The performance verification of SBS modified asphalt ensures that the material has excellent synergistic effects of high-temperature anti-deformation and low-temperature anti-cracking. Combined with the interlocking effect of low-abrasion basalt crushed stones, it enhances rutting resistance and skid resistance. The adhesion index strengthens the bonding of the asphalt-aggregate interface and effectively blocks the erosion of freeze-thaw moisture to the base layer. The interlayer strength monitoring during the construction process ensures the integrity of the composite sealing layer structure and inhibits the interlayer peeling caused by temperature stress; the control of the water permeability coefficient and skid resistance value forms a continuous waterproof barrier and optimizes the driving safety. Through the whole-process dynamic quality feedback mechanism, the best matching of material properties and construction technology is achieved, significantly improving the anti-ultraviolet aging, anti-low-temperature shrinkage and anti-fatigue damage abilities of the road surface in alpine environments and extending the full life cycle of the road.

[0031] As Figure 7 shown, the optimization of low-temperature construction includes adding 2% to 3% of low-temperature demulsifier to the emulsified asphalt of the bonding layer and increasing the spraying temperature to 65°C to 75°C when the ambient temperature is lower than 0°C, adding 0.3% to 0.5% of Sasobit® warm mix agent to the micro-surfacing mixture to reduce the construction temperature to 5°C to 10°C. The supplementary measures in plateau areas include adding 1% to 2% of nano-TiO2 anti-aging agent to the wearing course in areas with strong ultraviolet radiation to improve the weather resistance of asphalt.

[0032] Through the collaborative optimization of low-temperature adaptable materials and processes, the construction efficiency and service performance of cold-region pavements are significantly improved. The demulsifier composite modification technology enhances the interfacial penetration and bonding strength of emulsified asphalt at low temperatures, effectively inhibits the retention of interlayer moisture, and improves the interlayer stress transfer efficiency. The warm mix additive reduces the viscosity of the mixture, improves the compaction density and crack resistance of low-temperature paving, while reducing construction energy consumption and harmful gas emissions. The nano anti-aging agent delays the oxidative fracture of asphalt molecular chains through photocatalysis and ultraviolet shielding effects, enhancing the ultraviolet irradiation resistance and thermal shrinkage fatigue resistance of the wearing course. The process as a whole constructs a rapid consolidation and long-term protection system under low-temperature environments, achieving a balance between the low-temperature adaptability and the full-life cycle durability of pavements in cold and plateau regions, and ensuring the stable quality of winter construction and the safe operation of roads.

[0033] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Method for enhancing durability of asphalt pavement of alpine highway by composite seal coat, characterized in that: It includes the following steps: S1: Treatment of the original road surface and repair of diseases; S2: Construction of the bonding layer; S3: Construction of the crack-resistant waterproof layer; S4: Construction of the wearing course; S5: Quality inspection and acceptance; S6: Environmental adaptability adjustment; The treatment of the original road surface and repair of diseases include milling and cleaning, repair of cracks and potholes. The construction of the bonding layer includes material selection and spraying, and synchronous fiber reinforcement. The construction of the crack-resistant waterproof layer includes synchronous construction of the chip seal, rolling and compaction. The construction of the wearing course includes preparation of the micro-surfacing mixture, paving and curing. The quality inspection and acceptance include verification of material properties and monitoring of the construction process. The environmental adaptability adjustment includes optimization of low-temperature construction and supplementary measures in plateau areas.

2. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The milling and cleaning include using a precision milling machine to mill the original road surface with depth control, the milling depth is 3 mm to 5 mm, the cutter spacing does not exceed 8 mm, and the texture depth after milling needs to reach more than 0.6 mm. The surface residual debris is washed with a high-pressure water gun to ensure no floating dust, oil stains and loose particles, the moisture content is less than 2%. The repair of cracks and potholes includes for cracks with a width ≥ 2 mm, using epoxy resin grouting adhesive for perfusion, the grouting pressure is 0.3 MPa to 0.5 MPa, the curing time ≤ 2 hours, the tensile strength ≥ 5 Mpa. Local potholes are filled with cold patch material, and 3% to 5% of rubber powder is incorporated into the cold patch material, the compaction degree ≥ 95%, and the flatness error ≤ 3 mm.

3. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The material selection and spraying include using SBS high-elastic modified emulsified asphalt for the bonding layer, the softening point ≥ 85°C, the ductility at 5°C ≥ 35 cm, the demulsification time ≤ 30 seconds, the penetration depth ≥ 5 mm. The parameters of the spraying equipment are the asphalt temperature of 60°C to 70°C, the spraying amount of 1.2 kg / m² to 1.5 kg / m², the transverse overlap width ≤ 10 cm, and the longitudinal overlap error ≤ 5 cm. The synchronous fiber reinforcement includes evenly spreading basalt chopped fibers within 30 seconds after the emulsified asphalt is sprayed, the fiber length is 60 mm, the diameter is 7 μm, the spreading amount is 80 g / m² to 100 g / m², and the coverage rate ≥ 95%.

4. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The synchronous construction of the chip seal includes using 5 mm to 8 mm basalt chips, the crushing value ≤ 15%, the water absorption rate ≤ 1%, the spreading amount is 8 kg / m² to 10 kg / m², the coverage rate ≥ 85%. SBS modified asphalt is synchronously spread, the asphalt temperature is 130°C to 150°C, the viscosity ≥ 2000 Pa·s, and the embedding depth of the chips ≥ 2 / 3 of the particle size. The rolling and compaction include using a rubber-tyred roller with a weight of more than 26 t for rolling, the initial rolling temperature ≥ 130°C, the rolling speed is 2 km / h to 3 km / h, the number of rolling passes is 2, and the void ratio ≤ 8%.

5. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The preparation of the micro-surfacing mixture includes that the aggregate gradation is AC-10 gap gradation, the passing rate of the 4.75 mm sieve hole is 45% to 55%, the cement content of the filler is 1.5% to 2.0%, the residue content of the SBS modified emulsified asphalt is ≥65%, the mixing time is ≤30 seconds, the discharge temperature is 10°C to 30°C. The paving and curing include that the paving thickness is 10 mm to 12 mm, the paving speed is 4 m / min to 6 m / min, immediately after paving, it is statically pressed once with an 8 t double-drum roller, the final pressing temperature is ≥80°C, the natural curing time is ≥4 hours, when the ambient temperature is lower than 5°C, a hot air blanket is used to assist in temperature increase, and the vehicle speed limit during the initial stage of opening to traffic is ≤40 km / h.

6. The method for enhancing the durability composite seal coat of the asphalt pavement on alpine highway according to claim 1, characterized in that: The verification of the material performance includes that for each batch of SBS modified asphalt, the test indexes are softening point, ductility at 5°C, freeze-thaw splitting strength ratio ≥80%, and for the crushed stone, the test indexes are Los Angeles abrasion value ≤20%, adhesion grade ≥4.

7. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The monitoring of the construction process includes that the interlayer bond strength is sampled and inspected once every 500 m², the pull-out strength ≥0.8 MPa, the shear strength at -20°C ≥0.6 Mpa, the sampling frequency of the water permeability coefficient is once every 100 m, and the requirement is ≤50 mL / min, the skid resistance pendulum value BPN ≥55.

8. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, characterized in that: The optimization of low-temperature construction includes that when the ambient temperature is lower than 0°C, 2% to 3% of low-temperature demulsifier is added to the bonding layer emulsified asphalt, the spraying temperature is increased to 65°C to 75°C, and 0.3% to 0.5% of Sasobit® warm mix agent is incorporated into the micro-surfacing mixture to reduce the construction temperature to 5°C to 10°C.

9. The method for enhancing the durability of the asphalt pavement of alpine highways according to claim 1, wherein: The supplementary measures in plateau areas include that in areas with strong ultraviolet radiation, 1% to 2% of nano-TiO2 anti-aging agent is added to the wearing course to improve the weather resistance of the asphalt.

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