Chemical process of high-temperature asphalt anti-rut agent composite asphalt concrete

Abstract

The invention relates to the technical field of asphalt, in particular to a high-temperature asphalt anti-rut agent composite asphalt concrete chemical process which comprises the following steps: crushing polyethylene, mixing with maleic anhydride grafted polyethylene, and stirring at a high speed to obtain a premix; heating matrix asphalt to a molten state, carrying out heat preservation, adding the premix into the molten matrix asphalt, and carrying out high-speed shearing treatment to form a compatible modified asphalt system; respectively heating the coarse aggregate, the medium aggregate and the fine aggregate to a preset temperature, heating the mineral powder to a preset temperature, putting the heated coarse aggregate, medium aggregate, fine aggregate and mineral powder into a mixing device for dry mixing, then adding the compatible modified asphalt for wet mixing, loading the uniformly mixed asphalt concrete into a test mold, performing heat preservation, and compacting by using a double-sided compactor to obtain the modified asphalt concrete. And cooling to room temperature, and demolding to obtain the composite asphalt concrete. The compatibility modification design is introduced, and the interfacial compatibility of a traditional single polymer and asphalt is improved through the mediation effect of specific functional components.

Description

Technical Field

[0001] This invention relates to the field of asphalt preparation technology, specifically to a chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete. Background Technology

[0002] Rutting is a typical and widespread pavement defect in the transportation sector, significantly impacting road performance and maintenance costs. Rutting first disrupts pavement smoothness, reducing driving comfort and safety. Long-term rutting also leads to a decrease in the pavement's structural load-bearing capacity, accelerates pavement aging, and drastically shortens its service life. When rutting reaches a certain level, it often causes structural damage, requiring large-scale structural overhauls for repair. This not only consumes significant traffic resources but also significantly increases the overall maintenance cost throughout the road's lifecycle. Therefore, how to efficiently control and prevent rutting remains a crucial technical issue of long-term concern and urgent need for breakthroughs in the field of transportation engineering.

[0003] With the gradual development of rutting-resistant asphalt pavement technology, conventional rutting-resistant technologies have been able to improve the rutting resistance of pavements to a certain extent, thus basically suppressing rutting damage on highways and municipal roads under normal operating conditions. However, in actual engineering scenarios, due to complex factors such as insufficient precision in the process control of asphalt mixture construction and the long-term frequent passage of heavy-duty vehicles during road service, rutting still occurs in some special road sections, such as intersections and areas with frequent vehicle starts and stops. The applicability and reliability of existing technologies in dealing with such complex working conditions still have limitations.

[0004] From a technical perspective, existing asphalt concrete technologies have significant shortcomings: Firstly, ordinary asphalt concrete without anti-rutting modifiers exhibits weak deformation resistance under high-temperature conditions, making it difficult to meet the demands of heavy traffic and high-temperature environments. Secondly, even with conventional single anti-rutting agents, the anti-rutting effect faces significant limitations, and there is an inherent contradiction between improved high-temperature stability and increased low-temperature brittleness, failing to simultaneously address the dual requirements of high-temperature rutting resistance and low-temperature crack resistance for road surfaces under different temperature conditions. Furthermore, the parameter design of existing preparation processes lacks specificity and flexibility, failing to adapt to the characteristics of different modifier combinations. This results in poor stability and large performance fluctuations in the modified system, limiting the applicability of the technical solutions and making it difficult to effectively address the diverse construction conditions and usage requirements in actual engineering projects. Summary of the Invention

[0005] The primary objective of this invention is to provide a chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete.

[0006] A further objective of this invention is to provide a chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete, comprising the following steps: pulverizing polyethylene and mixing it with maleic anhydride-grafted polyethylene, and stirring at high speed to obtain a premix; heating the base asphalt to a molten state and maintaining the temperature, adding the premix to the molten base asphalt, and performing high-speed shearing to form a compatible modified asphalt system; heating coarse aggregate, medium aggregate, and fine aggregate to a preset temperature, heating mineral powder to a preset temperature, and dry-mixing the heated coarse aggregate, medium aggregate, fine aggregate, and mineral powder in a mixing device, then adding the compatible modified asphalt and wet-mixing; loading the uniformly mixed asphalt concrete into a mold, maintaining the temperature, compacting it with a double-sided compactor, cooling to room temperature, and demolding to obtain composite asphalt concrete.

[0007] Preferably, during the preparation of the premix, surface-modified nano-silica is added to the mixture of polyethylene and maleic anhydride-grafted polyethylene, and the mixture is stirred at high speed to obtain a premix containing surface-modified nano-silica.

[0008] Preferably, the preparation steps of the surface-modified nano-silica include: adding nano-silica to an ethanol aqueous solution and ultrasonically dispersing it until a transparent and uniform suspension is formed; adding a silane coupling agent to the suspension, heating it to a preset temperature and stirring it at a constant temperature; vacuum drying the suspension after the reaction, and grinding it to obtain surface-modified nano-silica.

[0009] Preferably, the polyethylene in the premix is ​​replaced with a compound of polyethylene and styrene-butadiene rubber, wherein the mass ratio of polyethylene to styrene-butadiene rubber is 1:1.

[0010] Preferably, when the compound is mixed with maleic anhydride-grafted polyethylene, the mass of the maleic anhydride-grafted polyethylene is 20% of the total mass of the compound.

[0011] Preferably, the polyethylene is pulverized to 80 to 100 mesh, the mass ratio of polyethylene to maleic anhydride-grafted polyethylene is 3:1, and the high-speed stirring time is 10 minutes.

[0012] Preferably, the base asphalt is heated to 165 degrees Celsius and held for 30 minutes; during high-speed shearing, the shearing speed is 3500 revolutions per minute and the shearing time is 25 minutes, with the asphalt temperature controlled between 165 and 170 degrees Celsius during the shearing process.

[0013] Preferably, the coarse aggregate, medium aggregate, and fine aggregate are heated to 175 degrees Celsius, and the mineral powder is heated to 170 degrees Celsius; the dry mixing time is 30 seconds, the wet mixing time is 90 seconds, and the mixing temperature is maintained at 170 to 175 degrees Celsius during the wet mixing process.

[0014] Preferably, after the uniformly mixed asphalt concrete is poured into the test mold, it is kept at 175 degrees Celsius for 40 minutes, and each side is compacted 75 times by a double-sided compactor.

[0015] Preferably, the base asphalt is heated to 170 degrees Celsius; during high-speed shearing, the shearing speed is 4000 rpm and the shearing time is 30 minutes; during aggregate mixing, the aggregate heating temperature is 175 degrees Celsius; after the uniformly mixed asphalt concrete is poured into the test mold and compacted, the heat preservation time is 45 minutes.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention introduces a compatibility modification design. Through the mediating effect of specific functional components, it improves the interfacial compatibility between traditional single polymers and asphalt at the chemical level, effectively avoiding the particle agglomeration phenomenon commonly seen during the modification process. This allows the polymer to be uniformly dispersed in the asphalt system and form a stable bond. This design significantly enhances the high-temperature deformation resistance of asphalt concrete, solving the problems of limited anti-rutting effect and performance improvement bottlenecks caused by insufficient compatibility of existing single anti-rutting agents. It ensures that the pavement can maintain good structural stability under high-temperature environments and heavy traffic, reducing the probability of rutting damage.

[0017] 2. This invention achieves complementary performance through multi-component synergistic optimization. While improving high-temperature stability, the introduction of specific elastic components and the regulation of the compatible system effectively offset the adverse effects of rigid modifying components on low-temperature performance. This not only avoids increased low-temperature brittleness but also optimizes low-temperature crack resistance. This design enables asphalt concrete to resist rutting deformation in high-temperature environments and adapt to temperature stress changes in low-temperature environments, effectively preventing low-temperature cracking. It achieves balanced adaptation of pavement performance in different temperature regions and seasons, significantly expanding the applicable climatic range of asphalt concrete.

[0018] 3. To address the issues of easy agglomeration and weak bonding between direct addition of nanoparticles and the asphalt system, this invention involves targeted surface chemical modification of the nanoparticles. Polar groups are introduced onto the nanoparticle surface through a coupling agent, enabling them to form a stable chemical bond with the asphalt-polymer system. Simultaneously, the synergistic effect of compatible components further promotes the uniform dispersion of nanoparticles within the system, fully leveraging the high specific surface area enhancement effect of the nanoparticles. This design not only avoids the destructive impact of nanoparticle agglomeration on system stability but also enhances the structural density and deformation resistance of the modified system through the synergistic effect of nanoparticles, asphalt, and polymers, ensuring stable performance of asphalt concrete during long-term service and reducing performance degradation.

[0019] 4. This invention employs a multi-polymer compound design, combined with the regulatory effect of compatible components, to solve the problems of poor compatibility and easy separation of different components in existing polymer compounding technologies. Through a reasonable ratio of rigid and elastic polymers, complementary properties of rigid deformation resistance and elastic crack resistance are achieved. Simultaneously, with the mediation of compatible components, different polymers can form an integrated network structure with asphalt and nanoparticles, exerting a synergistic enhancement effect. This not only further improves high-temperature rutting resistance and low-temperature crack resistance, but also enhances the flexibility and fatigue resistance of asphalt concrete, extends the pavement's ability to resist repeated loads, and reduces fatigue damage.

[0020] 5. The three-stage chemical modification system of this invention significantly enhances the interfacial adhesion between asphalt and aggregates through optimization of asphalt components and regulation of interfacial interactions. On the one hand, the modified asphalt itself exhibits increased viscosity and cohesion, enabling it to better coat the aggregate surface; on the other hand, the synergistic effect of nanoparticles and compatible components fills tiny voids on the aggregate surface, reducing interfacial defects and mitigating the damage to interfacial adhesion caused by moisture intrusion. This design significantly improves the water stability of asphalt concrete, effectively resisting water-induced spalling, loosening, and other defects. Simultaneously, the enhanced interfacial adhesion and the densification of the system structure also significantly improve the overall structural strength of asphalt concrete, enabling it to better withstand traffic loads and further extending the service life of the pavement.

[0021] 6. The stepped preparation process designed in this invention, through precise design of premixing, temperature control, and shear parameter optimization, possesses excellent flexibility and adaptability. Process parameters can be specifically adjusted according to the characteristics of different modifier combinations, ensuring that all components react fully and disperse uniformly during preparation. This effectively avoids the problems of poor adaptability and large performance fluctuations caused by fixed parameters in existing processes. Simultaneously, the process steps are clear and the operation is controllable, requiring no special or complex equipment. It is easily integrated with existing asphalt concrete production lines, lowering the technical threshold and modification costs for industrial production, facilitating the promotion and application of the technology, and meeting the construction needs of road projects of different scales.

[0022] 7. This invention significantly extends the service life of asphalt concrete by improving its high-temperature rutting resistance, low-temperature crack resistance, water stability, and structural strength, thereby reducing the frequency of medium and major repairs during use. Simultaneously, the improved pavement performance also reduces indirect costs such as traffic delays and vehicle maintenance caused by pavement distress. From a life-cycle perspective, although this invention introduces specific modifying components during the preparation stage, it effectively reduces the overall cost of road construction and operation by decreasing later maintenance investment and extending road service life, bringing significant economic and social benefits to traffic engineering.

[0023] 8. This invention enhances the high-temperature rutting resistance and structural stability of asphalt concrete, enabling it to better withstand the frequent load impacts and shear stresses generated by vehicle start-stop cycles in special road sections, effectively reducing rutting deformation in such sections. This design specifically addresses the limitations of existing technologies in complex working conditions, providing a more reliable technical solution for pavement construction in special road sections and further improving the overall quality and reliability of road engineering. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1: Raw material ratio Based on the total mass of asphalt concrete, the composition is asphalt base 6.0%, coarse aggregate 58.0%, medium aggregate 22.0%, fine aggregate 12.0%, mineral powder 2.0%, polyethylene 0.3%, and maleic anhydride grafted polyethylene 0.1%.

[0026] Chemical process steps: The first step is premixing and compatibility treatment of the anti-rutting agent: Polyethylene is pulverized to 80-100 mesh and mixed with maleic anhydride-grafted polyethylene at a mass ratio of 3:1. The mixture is stirred at high speed at room temperature for 10 minutes until homogeneous, yielding a polyethylene-maleic anhydride-grafted polyethylene premix. The polar carboxyl groups in the maleic anhydride-grafted polyethylene molecular chain act as a bridge, with one end compatible with the non-polar polyethylene chain segment and the other end reacting chemically with the hydroxyl groups in the asphalt molecules. This fundamentally improves the compatibility between polyethylene and asphalt, avoiding the particle agglomeration phenomenon commonly seen in traditional single polyethylene modification.

[0027] The second step is asphalt chemical modification: The base asphalt is heated to 165 degrees Celsius and kept at that temperature for 30 minutes until it is completely melted. The above premix is ​​slowly added, and a high-speed shearing machine is turned on to shear at a speed of 3500 rpm for 25 minutes. During the shearing process, the asphalt temperature is strictly controlled between 165 and 170 degrees Celsius to ensure that the polyethylene is completely melted and reacts with the asphalt molecules through an interface grafting reaction with maleic anhydride-grafted polyethylene, forming a stable and compatible modified asphalt system.

[0028] The third step is aggregate mixing and composite molding: coarse, medium, and fine aggregates are heated to 175 degrees Celsius, and mineral powder is heated to 170 degrees Celsius. They are then added to a forced mixer in sequence according to the proportion and dry-mixed for 30 seconds to ensure uniform aggregate temperature. Then, compatible modified asphalt is added and wet-mixed for 90 seconds, maintaining the mixing temperature at 170 to 175 degrees Celsius to prevent the grafted modified structure from being damaged due to asphalt cooling. The uniformly mixed asphalt concrete is then poured into a Marshall mold and kept at 175 degrees Celsius for 40 minutes. Each side is compacted 75 times using a double-sided compactor. After naturally cooling to room temperature, the concrete is demolded to obtain the composite asphalt concrete specimen.

[0029] Example 2: Raw material ratio: Based on the optimization of Example 1, the composition of the asphalt concrete by total mass is asphalt 6.0%, coarse aggregate 57.8%, medium aggregate 22.0%, fine aggregate 12.0%, mineral powder 2.0%, polyethylene 0.3%, maleic anhydride-grafted polyethylene 0.1%, and surface-modified nano-silica 0.2%. By reducing a small amount of coarse aggregate, the aggregate gradation is kept stable, ensuring that the addition of nanoparticles does not affect the aggregate skeleton structure.

[0030] Chemical process steps: The first step is surface modification of nano-silica: Nano-silica is added to an ethanol-water solution at a mass ratio of 9:1, and ultrasonically dispersed for 15 minutes to form a transparent and uniform suspension. Then, 3% (by mass) of silane coupling agent KH-550 (based on the mass of nano-silica) is added to the suspension, and the mixture is heated to 60°C and stirred for 2 hours. The silane coupling agent KH-550 hydrolyzes to generate silanol groups, which undergo a condensation reaction with the hydroxyl groups on the surface of the nano-silica, introducing amino polar groups onto the surface of the nanoparticles. The resulting suspension is then vacuum-dried at 80°C for 4 hours and ground to 100 mesh to obtain surface-modified nano-silica. This step solves the problems of severe agglomeration and weak interfacial bonding with the asphalt system when traditional nanoparticles are directly added, improving the compatibility of nanoparticles with the asphalt-polymer system through chemical modification.

[0031] The second step is the preparation of the composite premix: the polyethylene-maleic anhydride grafted polyethylene premix from Example 1 is mixed with surface-modified nano-silica and stirred at high speed for 15 minutes. The carboxyl groups in the maleic anhydride grafted polyethylene molecular chain form hydrogen bonds with the amino groups on the surface of nano-silica, which further improves the dispersion uniformity of nanoparticles in the premix and lays the foundation for subsequent asphalt modification.

[0032] The third step, asphalt modification and molding: Using the asphalt heating temperature and shearing equipment of Example 1, the premix was replaced with a polyethylene-maleic anhydride grafted polyethylene-surface modified nano silica composite premix, and the shearing temperature was adjusted to 170 degrees Celsius, which is more conducive to the diffusion and dispersion of nanoparticles in molten asphalt; the aggregate mixing and molding parameters were kept consistent with those of Example 1 to ensure process continuity and comparability, and finally a two-stage composite system of "polymer compatible network-nanoparticle reinforcement" was formed.

[0033] Example 3: Raw material ratio: Based on the optimization of Example 2, the composition of the asphalt concrete by total mass is as follows: base asphalt 6.0%, coarse aggregate 57.7%, medium aggregate 22.0%, fine aggregate 12.0%, mineral powder 2.0%, polyethylene 0.2%, styrene-butadiene rubber 0.2%, maleic anhydride-grafted polyethylene 0.1%, and surface-modified nano-silica 0.2%. The single polyethylene in Example 2 was replaced with a 1:1 blend of polyethylene and styrene-butadiene rubber, while maintaining the total amount of anti-rutting agent unchanged. This utilizes the rigidity of polyethylene and the elasticity of styrene-butadiene rubber to achieve complementary properties.

[0034] Chemical process steps: The first step is polymer compounding and premixing: Polyethylene is pulverized to 80-100 mesh, and styrene-butadiene rubber (SBR) is pulverized to 100 mesh. They are mixed in a 1:1 mass ratio. Maleic anhydride-grafted polyethylene (MPGPE) is added at 20% of the total polymer mass, and the mixture is stirred at high speed for 15 minutes. MPGPE not only promotes the compatibility of polyethylene and asphalt, but also interacts with the elastic segments of SBR through its polar groups. This solves the problems of poor compatibility and easy delamination between polyethylene and SBR in traditional polymer compounding systems. Simultaneously, the elastic groups of SBR can counteract the low-temperature brittleness caused by polyethylene and nanoparticles.

[0035] The second step is the preparation of a multifunctional composite premix: the above polymer compound premix is ​​mixed with the surface-modified nano silica prepared in Example 2, and ultrasonically dispersed for 10 minutes. Ultrasonic vibration is used to break up any micro-agglomerations that may exist in the nanoparticles, ensuring that the nanoparticles are in full contact with the two polymer particles to form a multi-component composite structure of "rigidity-elasticity-reinforcement".

[0036] The third step is deep asphalt modification: the base asphalt is heated to 170 degrees Celsius, multifunctional composite premix is ​​added, the speed of the high-speed shearing machine is increased to 4000 rpm, and the shearing time is extended to 30 minutes. The higher shear strength and longer shearing time ensure that polyethylene and styrene-butadiene rubber are completely melted and fully react with nanoparticles and asphalt molecules to build an integrated network. The aggregate mixing temperature is increased to 175 degrees Celsius to match the melting characteristics of styrene-butadiene rubber. The heat preservation time after compaction is extended to 45 minutes to ensure that the chemical reaction between multiple components is fully carried out, and finally a composite asphalt concrete specimen with balanced comprehensive performance is obtained.

[0037] Comparative Example 1: The raw material composition is 6.0% base asphalt, 58.4% coarse aggregate, 22.0% medium aggregate, 12.0% fine aggregate, and 2.0% mineral powder, without any anti-rutting functional components. Except for the absence of anti-rutting agent pretreatment and asphalt modification, the process steps, including aggregate heating, mixing, and molding temperatures and times, are completely consistent with Example 1, representing the conventional technical level of existing unmodified asphalt concrete.

[0038] Comparative Example 2: The raw material ratio is 6.0% base asphalt, 58.0% coarse aggregate, 22.0% medium aggregate, 12.0% fine aggregate, 2.0% mineral powder, and 0.4% polyethylene. The polyethylene content is consistent with the total content of polyethylene and maleic anhydride-grafted polyethylene in Example 1. The process steps are the same as in Example 1, except that the maleic anhydride-grafted polyethylene premixing step is deleted. Polyethylene is directly added to molten asphalt for shear modification, representing a typical implementation method of single polymer modification in the prior art.

[0039] Comparative Example 3: The raw material ratio is exactly the same as in Example 2, except that the surface-modified nano-silica is replaced with ordinary silica. The ordinary silica has a particle size of 5 to 10 micrometers and has not undergone surface modification with a silane coupling agent. The process steps are the same as in Example 2, representing a conventional improvement scheme for directly adding inorganic fillers in the prior art.

[0040] Comparative Example 4: The raw material ratios are exactly the same as in Example 3, except that the maleic anhydride-grafted polyethylene component is removed. The process steps are the same as in Example 3, representing a prior art approach of polymer compounding with nanoparticle incorporation but lacking compatible and synergistic design.

[0041] Test standards and items: According to JTJ052-2000 Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering, key performance tests were conducted on the asphalt concrete specimens of each example and comparative example, focusing on high-temperature rutting resistance, while comprehensively evaluating low-temperature crack resistance and water stability. The test items included: High-temperature rutting resistance: dynamic stability, test conditions are 60 degrees Celsius and 0.7 MPa, and the average value is taken for each group of tests in 3 tests. Low temperature crack resistance: Low temperature bending strain, the test conditions are -10 degrees Celsius, loading rate of 50 mm per minute, and three tests are conducted for each group and the average value is taken; Water stability: Residual Marshall stability was tested after vacuum saturation for 48 hours, and the ratio to the standard stability was calculated. Each group was tested 3 times and the average value was taken. High-temperature structural strength: Marshall stability, tested at 60 degrees Celsius, with three tests per group and the average value taken.

[0042] The test results are shown in Table 1 below: The results can be analyzed as follows from Table 1 above: Existing single-polymer modification schemes, such as Comparative Example 2, are limited by insufficient compatibility. Polyethylene is prone to agglomeration in asphalt, and its dynamic stability is only 1058 cycles / mm, representing a mere 28.1% improvement over the control group, indicating limited performance enhancement. Example 1 of this invention, through a compatibility modification design using maleic anhydride-grafted polyethylene, improves the interfacial bonding between polyethylene and asphalt at the chemical level, increasing the dynamic stability to 1532 cycles / mm, a 44.8% improvement over Comparative Example 2, significantly breaking through the performance ceiling of existing single-polymer modifications.

[0043] In existing technologies, the direct addition of inorganic fillers, as in Comparative Example 3 using unmodified ordinary silica, not only fails to achieve the nano-reinforcing effect but also leads to decreased system stability due to agglomeration, with a dynamic stability of only 1325 cycles / mm, an improvement of only 12.6% compared to Example 1. Example 2 of this invention, through surface modification with a silane coupling agent, enables nano-silica to form a stable chemical bond with the asphalt-polymer system, resulting in a 44.8% improvement in dynamic stability compared to Example 1 and a 67.4% improvement compared to Comparative Example 3, thus solving the technical problem of poor incorporation effects of existing inorganic fillers.

[0044] In existing technologies, polymer compounding schemes without compatibilizers, such as Comparative Example 4, are prone to stratification and separation due to poor compatibility between components, resulting in a dynamic stability of only 1865 cycles / mm, which is 15.9% lower than that of Example 2. Example 3 of this invention, through a synergistic compatibility design of polyethylene-styrene-butadiene rubber compound and maleic anhydride-grafted polyethylene, achieves a dynamic stability of 2542 cycles / mm, an improvement of 14.6% compared to Example 2, 36.3% compared to Comparative Example 4, and 207.7% compared to the blank group. This performance improvement far exceeds that of any existing single-modification or simple compounding scheme.

[0045] Existing technologies generally suffer from the inherent contradiction of being stable at high temperatures but brittle at low temperatures: After improving dynamic stability, the low-temperature bending strain of Comparative Example 2 decreased to 2680 microstrain, a decrease of 6.0% compared to the blank group; Due to the lack of compatibilizer, the polyethylene and styrene-butadiene rubber were unevenly dispersed in Comparative Example 4, resulting in a low-temperature bending strain of only 2520 microstrain, a decrease of 11.6% compared to the blank group.

[0046] This invention effectively resolves this contradiction through systematic design: In Example 1, while significantly improving dynamic stability, the low-temperature bending strain remained at 2720 microstrains, only 4.6% lower than the blank group; In Example 2, after adding surface-modified nano-silica, the low-temperature bending strain increased to 2780 microstrains, approaching the level of the blank group; In Example 3, through the optimization of the elastic complementary and compatible system of styrene-butadiene rubber, the low-temperature bending strain reached 2910 microstrains, 2.1% higher than the blank group, achieving simultaneous optimization of high-temperature stability and low-temperature crack resistance.

[0047] The residual Marshall stability and Marshall stability of each embodiment were consistently superior to those of the comparative example: Example 3 achieved a residual stability of 86.8% and a Marshall stability of 9.8 kN, representing improvements of 7.8% and 36.1% respectively compared to the control group, and improvements of 4.4% and 12.6% respectively compared to Comparative Example 4. This result demonstrates that the three-stage chemical modification system of this invention not only optimizes the compatibility and dispersibility of each component, but also significantly enhances the interfacial adhesion between asphalt and aggregates, reduces the risk of water damage, and improves the overall structural strength. Existing technologies can only achieve limited improvements in a single performance aspect and cannot meet multi-dimensional performance requirements; their overall performance is far inferior to that of this invention.

[0048] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete, characterized in that, The process includes the following steps: pulverizing polyethylene and mixing it with maleic anhydride-grafted polyethylene, then stirring at high speed to obtain a premix; heating the base asphalt to a molten state and maintaining the temperature, adding the premix to the molten base asphalt, and performing high-speed shearing to form a compatible modified asphalt system; heating coarse aggregate, medium aggregate, and fine aggregate to preset temperatures, heating mineral powder to preset temperatures, adding the heated coarse aggregate, medium aggregate, fine aggregate, and mineral powder to a mixing equipment for dry mixing, then adding the compatible modified asphalt for wet mixing, filling the uniformly mixed asphalt concrete into a mold, maintaining the temperature, compacting it with a double-sided compactor, cooling to room temperature, and then demolding to obtain composite asphalt concrete.

2. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 1, characterized in that, In the preparation process of the premix, surface-modified nano-silica is added to the mixture of polyethylene and maleic anhydride-grafted polyethylene, and the mixture is stirred at high speed to obtain a premix containing surface-modified nano-silica.

3. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 2, characterized in that, The preparation steps of the surface-modified nano-silica include: adding nano-silica to an ethanol aqueous solution and ultrasonically dispersing it until a transparent and uniform suspension is formed; adding a silane coupling agent to the suspension, heating it to a preset temperature and stirring it at a constant temperature; vacuum drying the suspension after the reaction, and grinding it to obtain surface-modified nano-silica.

4. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 2, characterized in that, The polyethylene in the premix is ​​replaced by a compound of polyethylene and styrene-butadiene rubber, wherein the mass ratio of polyethylene to styrene-butadiene rubber is 1:

1.

5. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 4, characterized in that, When the compound is mixed with maleic anhydride-grafted polyethylene, the mass of the maleic anhydride-grafted polyethylene is 20% of the total mass of the compound.

6. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 1, characterized in that, The polyethylene is pulverized to 80 to 100 mesh, the mass ratio of polyethylene to maleic anhydride-grafted polyethylene is 3:1, and the high-speed stirring time is 10 minutes.

7. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 1, characterized in that, The base asphalt is heated to 165 degrees Celsius and held for 30 minutes; during high-speed shearing, the shearing speed is 3500 revolutions per minute and the shearing time is 25 minutes, with the asphalt temperature controlled between 165 and 170 degrees Celsius during the shearing process.

8. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 1, characterized in that, The coarse, medium, and fine aggregates are heated to 175 degrees Celsius, and the mineral powder is heated to 170 degrees Celsius. The dry mixing time is 30 seconds, and the wet mixing time is 90 seconds. During the wet mixing process, the mixing temperature is maintained at 170 to 175 degrees Celsius.

9. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 1, characterized in that, After the uniformly mixed asphalt concrete is poured into the test mold, it is kept at 175 degrees Celsius for 40 minutes, and then compacted 75 times on each side with a double-sided compactor.

10. The chemical process for high-temperature asphalt anti-rutting agent composite asphalt concrete according to claim 4, characterized in that, The base asphalt is heated to 170 degrees Celsius; during high-speed shearing, the shearing speed is 4000 revolutions per minute and the shearing time is 30 minutes; during aggregate mixing, the aggregate is heated to 175 degrees Celsius; after the uniformly mixed asphalt concrete is poured into the test mold and compacted, the heat preservation time is 45 minutes.

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