Temperature-sensitive composite binder and method for repairing damaged asphalt pavement

Abstract

This invention relates to the field of road maintenance engineering technology, specifically disclosing a temperature-sensitive composite adhesive and a method for repairing damaged asphalt pavements. The temperature-sensitive composite adhesive uses ordinary emulsified asphalt as a base material, adding SBS modifier, styrene-butadiene rubber, a temperature-sensitive modifier, a stabilizer, and an antioxidant. The temperature-sensitive modifier is a melt blend of polyethylene glycol 4000 and polyethylene glycol 1000; the stabilizer is nano-montmorillonite; and the antioxidant is 2,6-di-tert-butyl-p-cresol. The proportions of the temperature-sensitive modifier and stabilizer are adjusted according to different climatic regions. The repair method using this adhesive includes the following steps: S1 gradient modification pretreatment of the bonding surface, S2 preparation and application of the temperature-sensitive composite adhesive, and S3 interface pressing and curing. The adhesive of this invention exhibits excellent high-temperature stability and low-temperature fluidity, resulting in high flexural and compressive strength of the repaired pavement. The interface is dense with no significant water seepage, meeting the needs for efficient and long-term repair of pavements with different climatic zones and varying degrees of damage, demonstrating good applicability.

Description

Technical Field

[0001] This invention relates to the field of road maintenance engineering technology, and more specifically, to a temperature-sensitive composite adhesive and a method for repairing damaged asphalt pavement. Background Technology

[0002] In my country's highway and municipal infrastructure construction, asphalt concrete pavement is widely used in various road projects, including high-grade highways, urban arterial roads, and secondary roads, due to its advantages such as good smoothness, high driving comfort, and convenient construction. However, under long-term traffic loads and environmental factors (temperature changes, rainwater erosion, etc.), asphalt pavement is prone to damage such as cracks, potholes, and loosening, affecting the quality of road traffic and its service life.

[0003] Currently, the industry mostly uses cold chiseling and hot patching techniques to repair damaged asphalt pavements. This method is efficient and cost-effective, but it has core technical flaws: In existing repair processes, the bonding surface is often left untreated or simply coated with ordinary emulsified asphalt, resulting in insufficient bonding strength, poor interfacial compatibility, and loose connection between the repair and the original pavement. Under repeated traffic loads, the repaired area is prone to secondary cracking and delamination, significantly shortening the repair life, increasing road maintenance costs, and failing to meet the long-term service requirements of high-grade highways. Furthermore, traditional adhesives and bonding surface treatments do not consider the impact of different climates and different degrees of damage on the bonding effect, resulting in poor versatility and difficulty in adapting to complex engineering scenarios.

[0004] Therefore, there is an urgent need to provide a temperature-sensitive composite adhesive and a method for repairing damaged asphalt pavements that can be adapted to multiple scenarios, has strong adhesion, and provides good repair quality. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of insufficient bonding strength, poor interface compatibility, poor climate adaptability, and poor versatility caused by the bonding surface treatment in the existing cold chiseling and hot repair process.

[0006] This invention is achieved through the following technical solution: This invention provides a temperature-sensitive composite adhesive, using ordinary emulsified asphalt as the base material, and adding SBS modifier, styrene-butadiene rubber, temperature-sensitive modifier, stabilizer and antioxidant. The temperature-sensitive modifier is a melt blend of polyethylene glycol 4000 and polyethylene glycol 1000, the stabilizer is nano-montmorillonite, and the antioxidant is 2,6-di-tert-butyl-p-cresol. The addition ratio of temperature-sensitive modifier and stabilizer is adjusted according to different climatic regions.

[0007] This temperature-sensitive composite adhesive uses ordinary emulsified asphalt as the base material and is prepared by adding specific proportions of SBS modifier, styrene-butadiene rubber, temperature-sensitive modifier, stabilizer, and antioxidant according to different climatic regions. This temperature-sensitive composite adhesive utilizes the temperature-sensitive response characteristics of the temperature-sensitive modifier to regulate the stretching and contraction state of the molecular chains in different climatic regions. Simultaneously, the components work synergistically to regulate the viscosity and curing rate of the adhesive, ensuring good flowability in different climatic regions, facilitating on-site application. Furthermore, it exhibits excellent curing performance, ensuring bond strength and adapting to the needs of road repair construction under diverse climatic conditions.

[0008] SBS modifier, as the core framework for asphalt modification, can form a network structure with asphalt, enhancing strength, high-temperature resistance, and deformation resistance. Styrene-butadiene rubber (SBR) molecular chains have high flexibility and can intercalate between SBS segments, supplementing low-temperature toughness and enhancing the system's flexibility, ductility, and adhesion, thus compensating for the shortcomings of SBS's hardness and low-temperature brittleness. Together, they form an interpenetrating polymer network, achieving a synergistic effect of rigidity and flexibility, ensuring that the binder does not soften at high temperatures or become brittle at low temperatures.

[0009] However, while the aforementioned interpenetrating polymer networks exhibit high strength at room temperature, their excessive viscosity and insufficient flowability during construction make them ineffective at penetrating micro-cracks in existing pavements. Polyethylene glycol 4000 and 1000, as reversible phase-change materials, exhibit significant phase change and viscosity-regulating characteristics in different climatic regions when melt-blended, and can precisely couple with the SBS-SBR elastic network. During natural construction in different climatic regions, by adjusting the addition ratio of the temperature-sensitive modifier, the elastic networks of polyethylene glycol, SBS, and styrene-butadiene rubber can synergize, achieving a temperature-sensitive response that is easy to flow during construction and exhibits strong adhesion after molding.

[0010] The stabilizer nano-montmorillonite is a fine-particle layered silicate. Its layered structure can be uniformly dispersed in emulsified asphalt, adsorbing asphalt micelles and polymer segments. This avoids component stratification and segregation caused by adjusting the amount of temperature-sensitive modifier, ensuring the uniformity of binder performance in different areas. Furthermore, the nano-montmorillonite and the SBS-SBR network form an inorganic-organic composite reinforcement structure, which can improve high-temperature stiffness and compensate for the potential weakness at high temperatures caused by the temperature-sensitive modifier.

[0011] 2,6-Di-tert-butyl-p-cresol, an antioxidant, is a highly effective phenolic antioxidant that can capture free radicals, inhibit oxidative cross-linking, protect the organic polymer network from damage by high temperature and ultraviolet radiation, and delay the aging failure of SBS and styrene-butadiene rubber. Nano-montmorillonite inhibits free radical diffusion through physical barrier, assisting the antioxidant in enhancing its anti-aging effect.

[0012] Ordinary emulsified asphalt provides basic adhesion and fluidity, allowing various modifiers and additives to disperse evenly and form a stable system. Ultimately, the components work synergistically to form a temperature-sensitive, easy-to-apply, firmly bonded, and well-balanced high and low temperature performance, as well as being anti-aging and durable for long-term road repair. This adhesive is compatible with conventional asphalt pavement repair mixtures.

[0013] Preferably, the mass percentage of temperature-sensitive regulators and stabilizers added is adjusted according to different climate regions, which include low-temperature regions with an average maximum temperature of ≤45℃ in the hottest month, medium-temperature regions with an average maximum temperature of 45-55℃ in the hottest month, and high-temperature regions with an average maximum temperature of ≥55℃ in the hottest month. In the low-temperature range, the temperature-sensitive regulator is 1.3%-1.5%, and the stabilizer is 0.8%-1.0%, with the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator being 1:1.5-1:2; in the medium-temperature range, the temperature-sensitive regulator is 1.0%-1.3%, and the stabilizer is 0.7%-0.9%, with the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator being 1:1-1:1. 5. In high-temperature areas, the temperature-sensitive modifier is 0.9%-1.1%, and the stabilizer is 0.6%-0.8%. Among them, the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1.5:1-2:1. The mass percentages of SBS modifier, styrene-butadiene rubber and antioxidant remain unchanged in all climate zones, which are 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 0.5% antioxidant, and the balance is ordinary emulsified asphalt.

[0014] Polyethylene glycol 1000 has a phase transition temperature of 35-40℃. When the road surface temperature reaches this range, it melts first, absorbing latent heat and reducing the viscosity of the binder. This is beneficial for sealing micro-cracks in old road surfaces and improving the road surface's self-healing ability. Polyethylene glycol 4000 has a phase transition temperature of 53-62℃, and then melts, absorbing a large amount of latent heat and slowing down the rate of temperature rise of the asphalt binder. The sequential response and synergistic effect of these two materials endow the binder with graded temperature-sensitive control characteristics.

[0015] When the road surface temperature is below the melting point of polyethylene glycol 1000 (<35℃), polyethylene glycol exists in a microcrystalline form, acting as a rigid filler to improve the modulus and resistance to deformation of the binder. As the road surface temperature rises to 35-40℃, formulations with a higher proportion of polyethylene glycol 1000 soften first, providing a gradual transition to flexibility and preventing brittle cracking. Therefore, in low-temperature regions, a higher proportion of polyethylene glycol 1000 is used in temperature-sensitive modifiers.

[0016] In medium-temperature and high-temperature zones, as temperature rises, the viscosity of asphalt decreases and its fluidity improves, reducing its reliance on temperature-sensitive modifiers. Excessive use of temperature-sensitive modifiers can actually lead to excessive softening at high temperatures; therefore, the proportion of temperature-sensitive modifiers added is gradually reduced. In medium-temperature zones, the temperature-sensitive modifier uses a balanced ratio of polyethylene glycol 1000 and polyethylene glycol 4000, balancing self-healing capabilities with high-temperature reserves. In high-temperature zones, polyethylene glycol 4000 has a higher proportion, utilizing its higher melting point and larger latent heat of phase change to delay the peak temperature of the pavement, thereby mitigating the risk of high-temperature deformation.

[0017] In low-temperature regions, the average annual temperature is typically low, resulting in slower demulsification and water evaporation of emulsified asphalt. A higher proportion of temperature-sensitive modifiers is required, making the system more prone to stratification; therefore, the proportion of stabilizers should be increased. In medium- and high-temperature regions, the proportion of stabilizers should be gradually reduced. SBS modifiers and styrene-butadiene rubber primarily provide basic elasticity, cohesive strength, and fatigue durability, forming the system's framework. Their effects do not significantly change with short-term construction temperatures. Antioxidants have a weak temperature correlation. With a fixed framework component and antioxidant, temperature adaptability can be fine-tuned by adjusting the dosage of temperature-sensitive modifiers and stabilizers, ensuring both versatility and precise regional adaptation.

[0018] Preferably, in the low-temperature region, the temperature-sensitive modifier is 1.4% and the stabilizer is 0.9%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1:1.8; in the medium-temperature region, the temperature-sensitive modifier is 1.2% and the stabilizer is 0.8%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1:1.2; in the high-temperature region, the temperature-sensitive modifier is 1.0% and the stabilizer is 0.7%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1.8:1; the mass percentages of SBS modifier, styrene-butadiene rubber, and antioxidant remain unchanged in each climate region, namely 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 0.5% antioxidant, and the balance being ordinary emulsified asphalt.

[0019] Preferably, the temperature-sensitive composite adhesive is prepared by the following method: A temperature-sensitive modifier is prepared by mixing polyethylene glycol 4000 and polyethylene glycol 1000, heating to 60-70°C, and stirring until completely melted to obtain a clear liquid. Ordinary emulsified asphalt is heated to 65-75°C, stirred evenly, and then SBS modifier, styrene-butadiene rubber, temperature-sensitive modifier, stabilizer, and antioxidant are added sequentially. The system temperature is maintained at 70-75°C while stirring rapidly. The mixture is then ground using a colloid mill, finally cooled to room temperature, and sealed for later use.

[0020] Furthermore, the stirring rate of ordinary emulsified asphalt after heating is 300-400 r / min. After adding SBS modifier, styrene-butadiene rubber, temperature-sensitive regulator, stabilizer, and antioxidant, the stirring rate is 400-500 r / min, and the grinding time in the colloid mill is 10-15 min. SBS modifier is an elastomer particle, insoluble in water, and does not easily mix automatically with emulsified asphalt. Increasing the stirring rate enhances the shear dispersion effect, ensuring uniform dispersion of each component and preventing SBS modifier agglomeration. Too short a grinding time will not result in thorough grinding, while too long a time will damage its properties due to high-speed shear; 10-15 min is ideal.

[0021] This invention also provides a method for repairing damaged asphalt pavement, comprising the following steps: S1 Gradient modification pretreatment of bonding surface, S2 Preparation and application of temperature-sensitive composite adhesive, and S3 Interface pressing and curing; wherein, step S2 uses the temperature-sensitive composite adhesive as described in any one of claims 1-3 or the temperature-sensitive composite adhesive prepared by the preparation method of claim 4.

[0022] By introducing a gradient modification pretreatment process for the bonding surface, developing a temperature-sensitive composite adhesive and designing compatibility parameters, and combining it with an interface pressing and curing process, a complete differentiated treatment system is formed for asphalt pavements in different climate regions, which significantly improves the bonding strength, anti-aging ability and scene adaptability of the bonding surface.

[0023] Preferably, in step S2, the application thickness of the temperature-sensitive composite adhesive is adjusted according to the degree of road surface damage: For minor road surface damage (crack width ≤ 5mm and / or pothole depth ≤ 2cm), the application thickness is 0.6-0.8mm; for moderate road surface damage (crack width 5-10mm and / or pothole depth 2-4cm), the application thickness is 0.8-1.0mm; for severe road surface damage (crack width > 10mm and / or pothole depth > 4cm), the application thickness is 1.0-1.2mm. The higher the degree of road surface damage, the larger the cracks and potholes, the more significant the interface stress concentration, and the worse the bonding interface conditions. Therefore, a thicker application of adhesive is required to achieve sufficient wetting, interlocking, and filling, ensuring an effective bonding area.

[0024] Preferably, step S1, the gradient modification pretreatment of the bonding surface, includes the following steps: S11 interface polishing, S12 interface modification treatment, and S13 interface drying control treatment; wherein, S12 interface modification treatment includes: uniformly spraying a silane coupling agent dilution onto the bonding surface, and then drying it at low temperature using an infrared drying device, wherein the silane coupling agent dilution is composed of vinyltrimethoxysilane and anhydrous ethanol in a volume ratio of 1:9-1:11; S13 drying control treatment includes: after drying, cooling to room temperature, detecting the moisture content of the bonding surface, and ensuring that the moisture content is ≤3%.

[0025] Vinyltrimethoxysilane is readily soluble in anhydrous ethanol. When diluted at a volume ratio of 1:9 to 1:11, the solution has a moderate viscosity and is easy to spray. Furthermore, no additional water needs to be added, as the trace amounts of moisture in the air are sufficient to meet its hydrolysis requirements, which is beneficial for subsequent drying control and is suitable for the pretreatment process of this method.

[0026] Further, after interface polishing, a silane coupling agent dilution solution with a volume ratio of vinyltrimethoxysilane to anhydrous ethanol of 1:10 is sprayed. The spraying rate of the silane coupling agent dilution solution is 0.2-0.3 L / m³. 2 It can evenly cover the bonding surface, and the ethanol is easily volatile, allowing for rapid drying at low temperatures without leaving any impurities, thus avoiding any impact on the adhesion between the adhesive and the bonding surface. The low-temperature drying temperature is 40-50℃, and the drying time is 10-15 minutes.

[0027] The surface of asphalt pavement contains a large number of hydroxyl groups. The siloxane groups of the silane coupling agent can undergo a condensation reaction with the hydroxyl groups to form stable Si-OC chemical bonds, forming a uniform and dense monomolecular-level siloxane film on the bonding surface, i.e., the interface modification layer. After applying the thermosensitive composite adhesive, the vinyl groups in vinyltrimethoxysilane can also undergo an addition reaction with the double bonds of the SBS modifier in the thermosensitive composite adhesive. At the same time, the ordinary emulsified asphalt base material in the adhesive undergoes physical adsorption and chemical wetting with the siloxane film, improving the interfacial bonding strength between the adhesive and the bonding surface. The silane coupling agent vinyltrimethoxysilane can optimize interfacial compatibility and structural density, and enhance waterproofness and structural stability.

[0028] Preferably, the S11 interface grinding is a gradient grinding method, specifically: first, a coarse grinding wheel is used to perform preliminary grinding on the bonding surface, then a fine grinding wheel is used to perform fine grinding on the bonding surface, and finally, a high-pressure airflow is used to blow it clean.

[0029] Specifically, the bonding surface is first initially ground using an 80-grit coarse grinding wheel, with a grinding depth controlled at 0.3-0.5 mm, to remove loose and aged layers. Then, a 120-grit fine grinding wheel is used for fine grinding, controlling the surface roughness Ra of the bonding surface to 4.0-5.5 μm. After grinding, existing conventional road repair equipment such as a small high-pressure air compressor is used to blow away surface dust and debris with a high-pressure airflow of 0.3-0.5 MPa. This gradient grinding treatment creates a uniformly rough surface structure, significantly increasing the contact area with the adhesive.

[0030] Preferably, the S3 interface pressing and curing includes the following steps: S31 interface pressing, S32 natural curing; wherein, step S31 is as follows: the repair mixture is laid on the bonding surface coated with adhesive, and the pressing pressure is adjusted according to the degree of pavement damage: for light pavement damage, the pressing pressure is 0.2-0.3 MPa; for moderate pavement damage, the pressing pressure is 0.3-0.4 MPa; for severe pavement damage, the pressing pressure is 0.4-0.5 MPa. The higher the degree of pavement damage, the more interface voids there are, requiring higher pressure to expel air and fill voids, forming a continuous and dense bonding interface. Low pressure is used for light damage to avoid the adhesive being squeezed out and resulting in insufficient adhesive; the pressing pressure is gradually increased for moderate and severe damage to ensure that the interface is fully saturated and firmly interlocked, so that the repair mixture and the original pavement form an integrated structure, effectively compensating for the defects of asphalt pavement damage, improving the repair quality, and achieving efficient and long-term repair of asphalt pavement damage.

[0031] Furthermore, a small-scale pressing device is used for uniform pressing, with the pressing speed controlled at 0.5-1.0 m / min, to ensure that the adhesive flows slowly and is fully interlocked under pressure, and to continuously expel interfacial air bubbles; the pressing temperature is maintained at 25-30℃, and the temperature-sensitive composite adhesive has moderate viscosity, excellent flowability and wettability.

[0032] Preferably, in step S32, the curing time is adjusted according to the climate region to ensure complete curing of the adhesive: 20-25 minutes for low-temperature regions, 15-20 minutes for medium-temperature regions, and 10-15 minutes for high-temperature regions. The lower the ambient temperature, the slower the emulsified asphalt breaks down and forms a film; therefore, the curing time is extended accordingly in low-temperature regions, and gradually shortened in medium-temperature and high-temperature regions.

[0033] The technical solution of the present invention has the following beneficial effects: (1) By forming a rigid-flexible elastic network with SBS modifier and styrene-butadiene rubber, the adhesive is guaranteed to resist deformation at high temperature and brittleness at low temperature; by using a gradient compound of temperature-sensitive regulator and stabilizer nano-montmorillonite composed of polyethylene glycol 4000 and polyethylene glycol 1000 in a specific ratio, the differences in rheological properties caused by different climate zones divided according to the average maximum temperature of the hottest month are compensated; by providing physical barrier and structural reinforcement through nano-montmorillonite, and by effectively inhibiting polymer aging and degradation through antioxidant, the multi-component synergistic effect makes the adhesive easy to apply, while also being easy to flow at low temperature, resistant to excessive softening at high temperature, having high bonding strength, and being water-resistant and aging-resistant, thus adapting to the road repair needs under different climatic conditions.

[0034] (2) The silane coupling agent used is vinyltrimethoxysilane, which is easily soluble in anhydrous ethanol. After dilution at a volume ratio of 1:10, the solution has a moderate viscosity and is easy to spray. Moreover, no additional water needs to be added, as the trace amount of moisture in the air is sufficient to meet its hydrolysis requirements, which is beneficial for subsequent drying control and is suitable for the pretreatment process of this method. Vinyltrimethoxysilane forms a dense and continuous siloxane film modified layer on the bonding surface. Through Si-OC chemical bonding and vinyl addition reaction, chemical bridging and interfacial compatibility enhancement are achieved between the inorganic pavement and the organic adhesive, which significantly improves the interfacial bonding strength, water damage resistance and aging resistance.

[0035] (3) For asphalt pavements with different climate zones and different degrees of damage, the addition ratio of temperature-sensitive modifier and stabilizer in temperature-sensitive composite adhesive, the coating thickness of temperature-sensitive composite adhesive, and the interface pressing pressure are precisely adjusted to achieve matching control of interface bonding and interlocking density. This effectively solves the problems of coarse parameters, uneven interface bonding, and easy occurrence of weak bonding and debonding in traditional repair processes. At the same time, it improves the anti-aging ability and water damage resistance of the bonding surface, breaking through the limitations of poor universality and unstable bonding effect of existing technologies. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are performed according to conventional conditions or conditions recommended by the manufacturer; where the manufacturers of the instruments, equipment, reagents, or raw materials used are not specified, they are all conventional products that can be purchased commercially.

[0037] Example 1 Damaged road surface area: Main roads in the western Sichuan plateau (average maximum road surface temperature in the hottest month ≤ 45℃), with large areas of cracks and potholes. Cracks are 11-12mm wide and potholes are 5-7cm deep. The road surface temperature was 40 degrees during construction, which is a low temperature area and a severe damage situation.

[0038] A method for repairing damaged asphalt pavement includes the following steps: S1 bonding surface gradient modification pretreatment: S11 Gradient Grinding: First, use an 80-grit coarse grinding wheel to perform preliminary grinding on the bonding surface, with the grinding depth controlled at 0.4mm, to remove the loose and aged layers on the surface; then use a 120-grit fine grinding wheel for fine grinding, so that the surface roughness Ra of the bonding surface is controlled at 5.0μm; after grinding, use a small high-pressure air compressor to blow away surface dust and debris with a high-pressure airflow of 0.4MPa.

[0039] S12 Interface Modification Treatment: A silane coupling agent dilution solution of vinyltrimethoxysilane and anhydrous ethanol at a volume ratio of 1:10 was uniformly sprayed onto the bonding surface at a spraying rate of 0.3 L / m². After spraying, the surface was dried at low temperature using an infrared drying device at 50°C for 15 min.

[0040] S13 Drying Control Treatment: After drying, cool to room temperature and test the moisture content of the bonding surface to ensure that the moisture content is ≤3%.

[0041] Preparation and application of S2 temperature-sensitive composite adhesive: The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.4% thermosensitive modifier, 1.0% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the thermosensitive modifier is 1:1.8.

[0042] Ordinary emulsified asphalt is heated to 75°C and stirred evenly at a rate of 400 r / min. Then, SBS modifier, styrene-butadiene rubber, temperature-sensitive regulator, stabilizer and antioxidant are added in sequence. The system temperature is maintained at 75°C and stirred rapidly at a rate of 500 r / min. Then, it is ground in a colloid mill for 15 min. Finally, it is cooled to room temperature and sealed for storage.

[0043] The coating thickness is 1.2mm.

[0044] S3 interface bonding and curing: S31 Interface Pressing: The conventional emulsified asphalt cold-mix repair mixture is laid on the bonding surface coated with adhesive, and precise pressing is carried out using a small pressing device. For severely damaged pavement, the pressing pressure is 0.5MPa, and the pressing is carried out at a uniform speed of 0.5m / min, while the pressing temperature is maintained at 25℃.

[0045] S32 Natural Curing: After pressing, natural curing is carried out for 25 minutes to ensure that the adhesive is completely cured.

[0046] Example 2 Damaged road surface area: Secondary roads in western Sichuan Basin (average maximum temperature of 45-55℃ in the hottest month), with cracks and loosening of the road surface, crack width of 5-8mm and pothole depth of 3-4cm. The road surface temperature was 50 degrees during construction, which is a medium temperature zone and a moderate damage situation.

[0047] The difference between this embodiment and Embodiment 1 is that: Preparation and application of S2 temperature-sensitive composite adhesive: The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.2% thermosensitive modifier, 0.8% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The thermosensitive modifier is composed of polyethylene glycol 4000 and polyethylene glycol 1000 in a ratio of 1:1.2.

[0048] The coating thickness is 1.0mm.

[0049] S31 Interface Pressing: For moderate road surface damage, the pressing pressure is 0.4 MPa.

[0050] S32 Natural Curing: Curing time is 20 minutes to ensure the adhesive is fully cured.

[0051] Example 3 Damaged road surface area: Residential roads in southern Sichuan (average maximum temperature of the hottest month ≥55℃), with minor cracks and wear on the road surface, crack width ≤5mm, pothole depth ≤2cm, and road surface temperature of 60 degrees during construction, belonging to the high temperature zone and minor damage.

[0052] The difference between this embodiment and Embodiment 1 is that: Preparation and application of S2 temperature-sensitive composite adhesive: The composition includes 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.0% thermosensitive modifier, 0.6% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the thermosensitive modifier is 1.8:1.

[0053] The coating thickness is 0.8mm.

[0054] S31 Interface Pressing: For minor road surface damage, the pressing pressure is 0.3 MPa.

[0055] S32 Natural Curing: Curing time is 15 minutes to ensure the adhesive is fully cured.

[0056] Comparative Example 1 Damaged road surface area: Same as in Example 1.

[0057] The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.0% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. No temperature-sensitive modifier is used. The remaining steps are the same as in Example 1.

[0058] Comparative Example 2 Damaged road surface area: Same as in Example 1.

[0059] The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.4% temperature-sensitive modifier, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1:1.8. The remaining steps are the same as in Example 1.

[0060] Comparative Example 3 Damaged road surface area: Same as in Example 1.

[0061] The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.6% temperature-sensitive modifier, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive modifier is 1:2.5. The remaining steps are the same as in Example 1.

[0062] Comparative Example 4 Damaged road surface area: Same as in Example 1.

[0063] The composition includes 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.6% thermosensitive modifier, 0.6% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the thermosensitive modifier is 1:1.8.

[0064] The remaining steps are the same as in Example 1.

[0065] Comparative Example 5 Damaged road surface area: Same as in Example 1.

[0066] The composition consists of 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 1.4% thermosensitive modifier, 0.6% nano-montmorillonite stabilizer, 0.5% antioxidant, and the remainder is ordinary emulsified asphalt base material. The thermosensitive modifier is composed of polyethylene glycol 4000 and polyethylene glycol 1000 in a ratio of 1:2.5.

[0067] The remaining steps are the same as in Example 1.

[0068] The properties of the adhesives in Examples 1-4 and Comparative Examples 1-5, including bond strength, softening point, viscosity, flexural strength, and compressive strength of the repaired pavement, were tested, and the pavement water seepage was observed.

[0069] The bond strength test method adopted standard JTG 3410-2025 T0773 Interlayer Bond Strength Test (Pull-out Method); the softening point test method adopted standard JTG 3410-2025 T0606 Asphalt Softening Point Test (Ring and Ball Method); the viscosity test method at 5℃ adopted standard JTG 3410-2025 T0621 Asphalt Standard Viscosity Test (Asphalt Standard Viscometer Method); the flexural strength and compressive strength of the repaired pavement were tested according to JTG 3410-2025 T0715 (Asphalt Mixture Flexural Test) and T0713 (Asphalt Mixture Compressive Strength Test), respectively. The performance test results are shown in Table 1. Table 1 Comparison of Performance Test Results

[0070] Results analysis: The temperature-sensitive composite adhesives used in Examples 1-4 are all high-adhesion modified emulsified asphalts. Their bond strength (1.18-1.36MPa) and softening point (72.1-76.3℃) are significantly higher than those of Comparative Example 1 (without temperature-sensitive modifier, 0.57MPa, 48.1℃). They have strong high-temperature stability and rutting resistance. Moreover, their low-temperature viscosity (19-28s) is lower than that of Comparative Example 1 (35s). The low low-temperature viscosity and good fluidity make them easy to apply.

[0071] Examples 1-4 demonstrate that through gradient modification pretreatment of the bonding surface, temperature-sensitive composite adhesive, and differentiated synergistic effects of interfacial compression curing, the performance of repaired pavements can be significantly improved under different temperature ranges and varying degrees of pavement damage. The flexural strength (2.2-3.2 MPa) and compressive strength (10.0-12.2 MPa) of the repaired pavement are significantly superior to those of Comparative Example 1 (1.6 MPa, 7.0 MPa) and Comparative Example 2 (1.9 MPa, 8.5 MPa), and the interface is dense with no significant water seepage, meeting the requirements for road seepage prevention.

[0072] Comparative Example 2 resulted in system stratification due to the lack of stabilizer, leading to decreased bonding performance (bonding strength 0.89 MPa, lower than 1.36 MPa in Example 1). Comparative Example 3 had an excessive amount of temperature-sensitive modifier (1.6%), and the ratio of polyethylene glycol 4000 to polyethylene glycol 1000 in the temperature-sensitive modifier was inappropriate (1:2.5), resulting in insufficient high-temperature performance. Comparative Example 4 had only an excessive amount of temperature-sensitive modifier, and Comparative Example 5 had only an improper ratio of polyethylene glycol 4000 to polyethylene glycol 1000 in the temperature-sensitive modifier. The adhesives and pavement repair performance of both were slightly better than those of Comparative Example 3, but significantly weaker than those of Examples 1-4.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A temperature-sensitive composite adhesive, characterized in that, Using ordinary emulsified asphalt as the base material, SBS modifier, styrene-butadiene rubber, temperature-sensitive modifier, stabilizer and antioxidant are added. The temperature-sensitive modifier is a melt blend of polyethylene glycol 4000 and polyethylene glycol 1000, the stabilizer is nano-montmorillonite, and the antioxidant is 2,6-di-tert-butyl-p-cresol. The addition ratio of temperature-sensitive modifier and stabilizer is adjusted according to different climate regions.

2. The temperature-sensitive composite adhesive according to claim 1, characterized in that, The mass percentage of temperature-sensitive regulators and stabilizers added is adjusted according to different climate regions. The climate regions include low-temperature regions where the average maximum temperature of the hottest month is ≤45℃, medium-temperature regions where the average maximum temperature of the hottest month is 45-55℃, and high-temperature regions where the average maximum temperature of the hottest month is ≥55℃. In the low-temperature region, the temperature-sensitive regulator is 1.3%-1.5%, and the stabilizer is 0.8%-1.0%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1:1.5-1:2; In the medium temperature range, the temperature-sensitive regulator is 1.0%-1.3%, and the stabilizer is 0.7%-0.9%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1:1-1:1.5; In high-temperature areas, the temperature-sensitive regulator is 0.9%-1.1%, and the stabilizer is 0.6%-0.8%. The mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1.5:1-2:

1. The mass percentages of SBS modifier, styrene-butadiene rubber, and antioxidant remained unchanged in all climate regions, namely 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 0.5% antioxidant, and the remainder being ordinary emulsified asphalt.

3. The temperature-sensitive composite adhesive according to claim 2, characterized in that, In the low-temperature region, the temperature-sensitive regulator is 1.4% and the stabilizer is 0.9%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1:1.8; In the medium temperature range, the temperature-sensitive regulator is 1.2% and the stabilizer is 0.8%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1:1.2; In the high-temperature region, the temperature-sensitive regulator is 1.0% and the stabilizer is 0.7%, wherein the mixing ratio of polyethylene glycol 4000 and polyethylene glycol 1000 in the temperature-sensitive regulator is 1.8:1; The mass percentages of SBS modifier, styrene-butadiene rubber, and antioxidant remained unchanged in all climate regions, namely 5.0% SBS modifier, 2.0% styrene-butadiene rubber, 0.5% antioxidant, and the remainder being ordinary emulsified asphalt.

4. The temperature-sensitive composite adhesive according to any one of claims 1 to 3, characterized in that, Prepared using the following method: Prepare the temperature-sensitive regulator for later use: Mix polyethylene glycol 4000 and polyethylene glycol 1000, heat to 60-70℃, and stir until completely melted to obtain a clear liquid; Heat ordinary emulsified asphalt to 65-75℃, stir evenly, and then add SBS modifier, styrene-butadiene rubber, temperature-sensitive regulator, stabilizer and antioxidant in sequence. Maintain the system temperature at 70-75℃ and stir rapidly. Then grind it with a colloid mill, and finally cool it to room temperature and seal it for later use.

5. A method for repairing damaged asphalt pavement, characterized in that, Includes the following steps: S1 Gradient modification pretreatment of bonding surface, S2 Preparation and application of temperature-sensitive composite adhesive, and S3 Interface pressing and curing; In step S2, the temperature-sensitive composite adhesive is prepared using the temperature-sensitive composite adhesive as described in any one of claims 1-3 or the preparation method of claim 4.

6. A method for repairing damaged asphalt pavement according to claim 5, characterized in that, In step S2, the application thickness of the temperature-sensitive composite adhesive is adjusted according to the degree of road surface damage: Minor road surface damage: Crack width ≤ 5mm and / or pothole depth ≤ 2cm, coating thickness 0.6-0.8mm; Moderate road surface damage: Crack width 5-10mm and / or pothole depth 2-4cm, coating thickness 0.8-1.0mm; Severe road surface damage: Crack width > 10mm and / or pothole depth > 4cm, coating thickness 1.0-1.2mm.

7. A method for repairing damaged asphalt pavement according to claim 5, characterized in that, Step S1, the gradient modification pretreatment of the bonding surface, includes the following steps: S11 interface polishing, S12 interface modification treatment, and S13 interface drying control treatment; The S12 interface modification treatment includes: uniformly spraying a silane coupling agent dilution onto the bonding surface, and then drying it at low temperature using an infrared drying device. The silane coupling agent dilution is composed of vinyltrimethoxysilane and anhydrous ethanol in a volume ratio of 1:9-1:

11. The S13 drying control process includes: after drying, cooling to room temperature, and testing the moisture content of the bonding surface to ensure that the moisture content is ≤3%.

8. A method for repairing damaged asphalt pavement according to claim 7, characterized in that, The S11 interface is polished using a gradient polishing method. The specific method is as follows: first, a coarse grinding wheel is used to perform preliminary polishing on the bonding surface, then a fine grinding wheel is used to perform fine polishing on the bonding surface, and finally, a high-pressure airflow is used to blow it clean.

9. A method for repairing damaged asphalt pavement according to claim 6, characterized in that, S3 interface bonding and curing includes the following steps: S31 interface pressing, S32 natural curing and solidification; Step S31 involves laying the repair mixture on the bonding surface coated with adhesive, and adjusting the compaction pressure according to the degree of road damage. The road surface is slightly damaged, and the compaction pressure is 0.2-0.3 MPa; The road surface is moderately damaged, and the compaction pressure is 0.3-0.4 MPa; The road surface is severely damaged, and the compaction pressure is 0.4-0.5 MPa.

10. A method for repairing damaged asphalt pavement according to claim 9, characterized in that, In step S32, adjust the curing time according to the climate zone to ensure that the adhesive is fully cured: 20-25 min for low temperature zone, 15-20 min for medium temperature zone, and 10-15 min for high temperature zone.

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