High-grade highway large-thickness asphalt pavement paving and compacting method and system

Abstract

This application discloses a method and integrated system for paving and compacting thick asphalt pavements on high-grade highways, belonging to the field of asphalt pavement construction technology in highway engineering. It is applicable to the construction of hot-mix asphalt pavements with a single-layer paving thickness of 16-20cm. This application utilizes a paver equipped with a reverse auger distributor and a double-layer composite screed to achieve anti-segregation paving and two-stage gradient pre-compaction, increasing the initial compaction degree to over 88%. Based on the viscosity-temperature characteristics of the mixture, three continuous temperature windows are defined, matching differentiated compaction processes. Static pressure kneading with a bump-type tire roller achieves full-depth compaction, balancing deep compaction degree and aggregate integrity. An infrared temperature sensor array enables intelligent closed-loop temperature control throughout the entire process, coupled with standardized joint treatment processes, ensuring uniform and controllable compaction quality across the entire pavement.

Description

Technical Field

[0001] This application belongs to the field of asphalt pavement construction technology for highway engineering, specifically relating to a method and system for paving and compacting thick asphalt pavement for high-grade highways. Background Technology

[0002] Currently, the construction of high-grade highways in my country is developing towards heavy-load traffic and long-life pavements. Asphalt pavement, as the mainstream pavement structure for high-grade highways, directly determines the service life and driving safety of the pavement through its construction quality. Paving and compaction are the core processes in asphalt pavement construction, directly determining key technical indicators such as pavement compaction degree, smoothness, and uniformity, and are also the core focus of industry technology research and development.

[0003] Currently, my country's "Technical Specifications for Construction of Highway Asphalt Pavement" recommends a single-layer paving thickness of no more than 10cm. For asphalt lower layers with a design thickness of 16-20cm, the industry mainstream adopts three types of construction techniques, all of which have insurmountable core defects: Traditional layered paving method: The designed thickness of 16-20cm is paved in two layers, each layer ≤8cm thick, using a conventional process of initial compaction with a double-drum roller, secondary compaction with a pneumatic tire roller, and final compaction with a static steel drum. This technology is mature, but layered construction requires spraying a tack coat, which can easily lead to interlayer adhesion attenuation and adhesion failure. Under heavy traffic, it is prone to interlayer shear cracks. It also has the disadvantages of multiple procedures, long construction period, and high overall cost.

[0004] Conventional thick single-layer paving method: A 12-15cm thick layer of asphalt mixture is paved in one go, using a heavy roller of 30t or more for high-frequency, high-amplitude compaction. This method reduces cold joints and simplifies the process, but with the increased single-layer thickness, it is difficult to guarantee the compaction of the bottom layer, easily leading to insufficient density of the bottom layer. Furthermore, the high-frequency, high-amplitude compaction used to improve the deep compaction will cause structural breakage of the surface aggregate, with the aggregate breakage rate generally reaching 8%-12% in the industry, seriously affecting the long-term skid resistance and durability of the pavement.

[0005] Warm-mix asphalt construction technology: By adding warm-mix additives to reduce the mixing and construction temperature of the mixture, the low-temperature construction window can be extended. However, it has the problems of slow initial strength development and insufficient early load-bearing capacity of the mixture. At the same time, the additives increase the material cost, which limits its large-scale promotion.

[0006] In summary, current asphalt pavement construction technologies consistently fail to simultaneously meet the demands of thick paving, high compaction, low aggregate breakage rate, and high uniformity. The core challenges are: First, layered paving leads to weakened interlayer adhesion, a primary cause of early pavement defects; second, conventional thick paving cannot balance deep compaction with aggregate integrity, easily resulting in a contradiction between insufficient compaction of the bottom layer and fragmented surface aggregate; third, large temperature gradients at joints and insufficient compaction easily lead to early defects such as cracking and loosening. Currently, no existing technology offers a construction solution that systematically addresses all of these challenges. Summary of the Invention

[0007] This application addresses the shortcomings of existing asphalt pavement construction techniques and mainly solves at least one or more of the following technical problems: 1. To address the issue that when the thickness of a single layer exceeds 15cm, the lower layer of the paving layer lacks sufficient density and fails to meet the requirements of standard construction specifications; 2. To solve the problem of aggregate breakage caused by heavy high-amplitude rolling, which reduces the anti-skid performance and structural durability of the road surface; 3. Solve the problem of uneven joint compaction and poor molding quality caused by large temperature gradient in the joint area.

[0008] To achieve the above objectives, In a first aspect, this application provides a method for paving and compacting thick asphalt pavements on high-grade highways, applicable to the construction of hot-mix asphalt pavements with a single-layer paving thickness of 16-20cm, wherein the hot-mix asphalt mixture is AC-25 or AC-30 dense-graded asphalt mixture, comprising the following steps: S1. Anti-segregation paving and two-stage gradient pre-compaction: A paver equipped with a spiral distributor with reverse spiral blades and a double-layer composite screed is used for continuous uniform paving. The double-layer composite screed applies two-stage vibration with differences in frequency and amplitude to the paved mixture, forming a paving layer with an initial compaction degree of not less than 88% based on the maximum theoretical density. S2. Differentiated compaction based on temperature windows: Based on the viscosity-temperature characteristics of asphalt mixtures, three continuous temperature windows are defined according to the measured internal temperature of the mixture at 1 / 2 of the paving layer thickness: high-temperature initial compaction, medium-temperature intermediate compaction, and low-temperature final compaction. Vibratory compaction is used in the high-temperature initial compaction window to form a stable aggregate skeleton. In the medium-temperature intermediate compaction window, a pneumatic tire roller with trapezoidal bumps is used for static compaction to achieve full-depth compaction of the paving layer. In the low-temperature final compaction window, oscillatory compaction is used to complete surface finishing and internal stress elimination. S3. Intelligent closed-loop temperature control: Real-time monitoring of the transverse temperature distribution of the paving layer along the paving width direction. When the temperature deviates from the preset threshold of the corresponding temperature window, the paver travel speed and / or the operating parameters of the compaction equipment are automatically adjusted to ensure that each compaction process is completed within the corresponding temperature window. S4. Synchronous compaction treatment of joints: For longitudinal joints and transverse construction joints, a special compaction process with matching temperature control is adopted to achieve the same compaction quality at the joints as that of the main road surface.

[0009] By adopting the above technical solutions, the bottleneck of deep compaction in thick paving can be overcome, increasing the initial compaction degree to over 88%. Combined with the deep static compaction of the pneumatic tire roller, the compaction degree of the bottom layer can be stably maintained at over 96% when the single-layer paving thickness is 16-20cm, solving the problem of "insufficient compaction of the bottom layer" in conventional thick paving. It also achieves protective compaction of aggregates, abandoning the process of relying on high-frequency, high-amplitude compaction with heavy rollers. While ensuring full-depth compaction, the aggregate breakage rate is stably controlled within 3%, guaranteeing the anti-skid performance and structural durability of the pavement. Furthermore, it achieves closed-loop temperature control throughout the entire process, stabilizing the lateral temperature difference of the paved layer. The temperature is controlled within 8℃ to solve the problem of uneven compaction caused by temperature segregation, ensuring uniform and controllable compaction quality across the entire road surface. Joint forming quality is significantly optimized, with joint flatness controlled within 2mm / 3m and joint density deviating from the main pavement by no more than 0.5%, reducing the probability of early joint defects. Simultaneously, construction efficiency and economy are improved; single-layer, one-time paving eliminates the need for layered or step-by-step operations, increasing overall construction efficiency by more than 30% compared to traditional layered paving, reducing roller fuel consumption by approximately 25%, and eliminating the need for interlayer tack coats, significantly shortening the construction period and reducing overall project costs. Furthermore, the process is highly adaptable and can be flexibly adapted to various working conditions.

[0010] Further, the double-layer composite screed in step S1 includes an upper reference screed and a lower high-frequency micro-amplitude vibration module; the vibration frequency of the upper reference screed is 20-30Hz and the amplitude is 0.8-1.2mm, the vibration frequency of the lower high-frequency micro-amplitude vibration module is 50-70Hz and the amplitude is 0.1-0.3mm; the continuous uniform paving speed of the paver is 2-4m / min, and the temperature of the hot-mix asphalt mixture entering the paving site is 160-180℃.

[0011] Furthermore, the specific steps of the differentiated compaction described in step S2 are as follows: Initial compaction process: In the high-temperature initial compaction window where the internal temperature of the mixture is not lower than 150℃, a double steel drum vibratory roller with a self-weight of 10-12t is used to statically compact or weakly vibrate for 1-3 passes with an amplitude of 0.3-0.8mm and a frequency of 30-40Hz, and the compaction speed is 2-3km / h. Secondary compaction process: In the medium-temperature secondary compaction window where the internal temperature of the mixture is 120-140℃, a block tire roller with a self-weight of 24-26t is used to statically compact the mixture 4-6 times with a tire inflation pressure of 300-500kPa and a compaction speed of 4-5km / h. Final compaction process: In the low-temperature final compaction window where the internal temperature of the mixture is 90-110℃, a vibratory roller with a self-weight of 10-13t is used to compact the mixture 2-3 times at a fixed angle of 10°-20° with the direction of travel until the wheel tracks are completely eliminated.

[0012] Furthermore, the bump-type tire roller used in the re-compaction process has bumps on the tire surface with an isosceles trapezoidal cross section, a top base width of 15-25mm, a bottom base width of 35-45mm, and a height of 25-35mm. The bumps are arranged in a staggered matrix on the tire surface, with a lateral spacing of 40-60mm and a longitudinal spacing of 70-90mm between adjacent bumps.

[0013] Furthermore, the specific logic of the intelligent closed-loop temperature control in step S3 is as follows: when the maximum lateral temperature difference of the paving layer is detected to exceed 10℃, the paver travel speed is automatically reduced by 0.5 to 1 m / min, while the speed of the auger distributor is increased by 10% to 20% until the maximum lateral temperature difference of the paving layer recovers to within 8℃; when the temperature of the mixture in the working section is detected to be close to the lower limit of the corresponding temperature window, the corresponding compaction equipment is automatically linked to increase the rolling speed to ensure that the compaction process is completed within the temperature window.

[0014] Furthermore, the specific process for the synchronous compaction treatment of the joint in step S4 is as follows: For longitudinal joints, a double-machine echelon paving is used to form a hot joint. The echelon paving spacing is controlled at 5-8m, and a 20cm wide uncompacted overlap strip is reserved. A road roller is used to compact the joint across the joint. When compacting, the already paved layer side is compacted 10-15cm wide first, and the newly paved layer side is compacted 10-15cm wide second. For transverse construction joints, vertical flat joints are used. Before paving, emulsified asphalt tack coat is applied to the joint section, and the mixture at the joint is preheated by a screed to ensure that the internal temperature of the mixture at the joint is not lower than 150℃. After paving, the mixture is first rolled transversely three times, and then transitioned to normal longitudinal rolling.

[0015] By adopting the above technical solutions, for longitudinal joints, the double-machine echelon paving forms a hot joint, and the echelon spacing is controlled, uncompacted overlap strips are reserved, and cross-joint compaction is carried out, which can ensure that the compaction quality of the joint is consistent with that of the main road surface. For transverse construction joints, the use of vertical flat joints, application of tack coat, preheating of the mixture at the joint, and compaction in a specific sequence can ensure that the internal temperature of the mixture at the joint is suitable and the compaction quality is consistent with that of the main road surface. This reduces the probability of early defects such as cracking, loosening, and water damage at the joint from the source, and controls the flatness of the joint to within 2mm / 3m, which is far better than the national standard requirement of ≤5mm / 3m. The joint density deviation from the main road surface does not exceed 0.5%.

[0016] Furthermore, when low-temperature construction is carried out at an ambient temperature below 5℃, the asphalt-aggregate ratio of the hot-mix asphalt mixture is 4.2% to 4.8%, and the paving entry temperature is not lower than 165℃; the internal temperature of the mixture in the initial compaction process is not lower than 135℃, the internal temperature of the mixture in the secondary compaction process is 105 to 125℃, and the internal temperature of the mixture in the final compaction process is 75 to 95℃. The final compaction uses a low-amplitude variable frequency vibratory roller with a frequency of 35 to 45Hz and an amplitude of 0.2 to 0.4mm.

[0017] Secondly, this application provides an integrated paving and compaction system for implementing the above-mentioned paving and compaction method, including an anti-segregation paving unit, a gradient compaction unit, and an intelligent monitoring and control unit that are interconnected in sequence. The anti-segregation paving unit includes a paver body, a auger distributor located at the rear of the paver body, and a double-layer composite screed; the auger distributor has reverse auger blades at both ends; the double-layer composite screed is configured to generate upper and lower layer vibrations with differences in frequency and amplitude. The gradient compaction unit includes a front-mounted double-drum vibratory roller, a central-mounted bump tire roller, and a rear-mounted vibratory roller that operate sequentially along the paving direction, respectively corresponding to the high-temperature initial compaction, medium-temperature secondary compaction, and low-temperature final compaction processes. The intelligent monitoring and control unit includes an array of infrared temperature sensors arranged along the paving width direction, and a main control PLC unit that is communicatively connected to the anti-segregation paving unit and the gradient compaction unit. The main control PLC unit is configured to send travel speed adjustment commands or compaction parameter adjustment commands to the anti-segregation paving unit and / or the gradient compaction unit based on the transverse temperature data of the paving layer collected by the infrared temperature sensor array, so as to ensure that each compaction process is completed within the corresponding temperature window.

[0018] By adopting the above technical solutions, anti-segregation paving and two-stage gradient pre-compaction are achieved, increasing the initial compaction degree of paving to over 88%. Combined with the deep static compaction of the pneumatic tire roller, the compaction degree of the bottom layer can be stably maintained at over 96% when the single-layer paving thickness is 16-20cm, solving the problem of "insufficient compaction of the bottom layer" in conventional large-thickness paving. The high-frequency, high-amplitude rolling of heavy rollers is abandoned; instead, pre-compaction improves the initial density. Combined with the static compaction process within a medium-temperature window, while ensuring full-depth compaction, the aggregate breakage rate is stably controlled below 3%, guaranteeing the road surface's anti-skid performance and structural durability. A full-width array of infrared temperature sensors monitors the lateral temperature distribution in real time, and adjusts the operating parameters of the paving and compaction equipment accordingly. The process effectively controls the lateral temperature difference of the paving layer to within 8℃, resolving the problem of uneven compaction caused by temperature segregation and achieving uniform and controllable compaction quality across the entire road surface. Through specialized techniques such as joint preheating and insulation, and gradient rolling across joints, the smoothness at the joints is controlled within 2mm / 3m, and the joint density deviation from the main pavement does not exceed 0.5%, reducing the probability of early-stage defects at the joints. Single-layer, one-time paving eliminates the need for layered or step-by-step operations, increasing overall construction efficiency by more than 30% compared to traditional layered paving, reducing roller fuel consumption by approximately 25%, and eliminating the need for interlayer tack coats, significantly shortening the construction period and reducing overall project costs. Furthermore, the process is highly adaptable, flexibly adapting to various working conditions such as wide / narrow road surfaces, normal / low-temperature construction, and substrate / modified asphalt mixtures.

[0019] Furthermore, the infrared temperature sensor array includes at least five sets of sensors, which are respectively arranged at the discharge port of the spiral distributor, the rear edge of the double-layer composite screed, the starting point of the initial pressing process, the starting point of the secondary pressing process, and the starting point of the final pressing process; the spacing between the measuring points of each set of sensors along the paving width direction is no more than 0.5m, the temperature measurement range is 50~200℃, and the detection accuracy is no less than ±1.5℃.

[0020] Furthermore, the rear-mounted vibratory roller can be replaced with a low-amplitude variable frequency vibratory roller, which has a vibration frequency of 35-45Hz and an amplitude of 0.2-0.4mm, and is used in low-temperature construction scenarios where the ambient temperature is below 5℃.

[0021] Furthermore, the double-layer composite ironing board includes an upper reference ironing board and a lower high-frequency micro-amplitude vibration module; the upper reference ironing board has a vibration frequency of 20-30Hz and an amplitude of 0.8-1.2mm, and the lower high-frequency micro-amplitude vibration module has a vibration frequency of 50-70Hz and an amplitude of 0.1-0.3mm; the double-layer composite ironing board is also equipped with a ceramic infrared heating module with a power density of not less than 15W / cm².

[0022] Furthermore, the self-weight of the centrally mounted bump-type tire roller is 24-26t, and the tire inflation pressure is adjustable within the range of 300-500kPa. The cross-section of the bumps on the tire surface is an isosceles trapezoid, with an upper base width of 15-25mm, a lower base width of 35-45mm, and a height of 25-35mm. The bumps are arranged in a staggered matrix on the tire surface. This application addresses the core pain points of existing technologies by providing an integrated technical solution of "dual-stage gradient pre-compaction, temperature window differentiated compaction, intelligent closed-loop temperature control, and standardized joint treatment," achieving at least the following technical effects: Breaking through the bottleneck of deep compaction in thick paving: By using a double-layer composite screed for two-stage gradient pre-compaction, the initial compaction degree of paving is increased to over 88%. Combined with the deep static pressure kneading of the bump-type tire roller, the compaction degree of the bottom layer of the paving can be stably maintained at over 96% when the single-layer paving thickness is 16-20cm. This solves the industry problem of "insufficient compaction of the bottom layer" in conventional thick paving and fully meets the requirements of high-grade highway construction specifications.

[0023] Achieving protective compaction of aggregates: This technology abandons the existing process logic that relies on high-frequency, high-amplitude compaction with heavy rollers. It improves the initial density through pre-compaction and combines it with a static pressure kneading process at a medium temperature window. While ensuring full-depth compaction meets the standards, it keeps the aggregate breakage rate stable at less than 3%, which is far lower than the industry average of 8% to 12% for traditional processes. This ensures the long-term anti-skid performance and structural durability of the road surface.

[0024] Closed-loop temperature control throughout the entire process significantly improves compaction uniformity: By monitoring the lateral temperature distribution in real time through an array of infrared temperature sensors deployed across the entire width, the operating parameters of the paving and compaction equipment are adjusted in conjunction with the paving and compaction equipment to keep the lateral temperature difference of the paving layer stable within 8℃, completely solving the problem of uneven compaction caused by temperature segregation and achieving uniform and controllable compaction quality across the entire road surface.

[0025] Significantly optimized joint forming quality: Through specialized processes such as joint preheating and insulation and gradient compaction across joints, the flatness of the joint is controlled within 2mm / 3m, which is far superior to the national standard requirement of ≤5mm / 3m. The joint density deviates from the main pavement by no more than 0.5%, which fundamentally reduces the probability of early defects such as cracking, loosening, and water damage at the joint.

[0026] Construction efficiency and economy are improved simultaneously: single-layer one-time paving eliminates the need for layered and step-by-step operations, improving overall construction efficiency by more than 30% compared to traditional layered paving, reducing roller fuel consumption by about 25%, and eliminating the need for interlayer tack coat, which significantly shortens the construction period and reduces the overall project cost; moreover, the process is highly adaptable and can be flexibly adapted to various working conditions such as wide / narrow road surfaces, normal / low temperature construction, and matrix / modified asphalt mixtures. Attached Figure Description

[0027] Figure 1This document presents a comprehensive flowchart of the application process for thick asphalt pavement paving and compaction. It illustrates the logical framework of the entire process, from construction preparation and working condition adaptation to the execution of core procedures and quality acceptance.

[0028] Figure 2 The application process includes an anti-segregation paving procedure and a closed-loop intelligent temperature control process for the paving phase. It demonstrates the paving technology with reverse spiral material distribution, the two-stage gradient pre-compaction process, and the intelligent closed-loop control logic for the lateral temperature difference of the paved layer.

[0029] Figure 3 The application requests a flowchart of the intelligent temperature control closed-loop process for differentiated compaction based on temperature windows and compaction stages. It demonstrates a three-stage compaction process that matches the viscosity-temperature characteristics of the mixture, a full-depth densification rolling process, and the intelligent temperature window control logic for the entire compaction process.

[0030] Figure 4 This document presents a flowchart for the application of simultaneous compaction treatment of joints and the acceptance of construction quality. It demonstrates the specific compaction techniques for longitudinal thermal joints and transverse construction joints, as well as the corresponding construction quality acceptance standards and judgment procedures. Detailed Implementation

[0031] The technical solution of this application is clearly and completely described below with reference to multiple sets of embodiments under different working conditions and comparative examples with existing technologies. The described embodiments are typical application conditions of this application and are not all embodiments. Based on the technical concept of this application, those skilled in the art can extend it to obtain other derivative embodiments without creative effort, all of which fall within the protection scope of this application.

[0032] Example 1: Construction of a 18cm thick asphalt base course under conventional climatic conditions This embodiment is applied to the construction of the asphalt lower layer of a two-way four-lane high-grade highway. The single-layer design paving thickness is 18cm, the single-width paving width is 11.25m, the continuous construction length is 3km, the on-site ambient temperature is 25℃, and the weather is windless and sunny.

[0033] Raw materials and mix proportions: AC-30 dense-graded hot-mix asphalt mixture is used for construction, with No. 70 Grade A road petroleum asphalt, an asphalt-aggregate ratio of 4.5%, a Marshall stability of ≥8kN, and a void ratio controlled between 3% and 6%. The mixing temperature of the mixture is 165-175℃, the paving temperature at the site is ≥155℃, and the entire transportation process is fully covered with thermal tarpaulin.

[0034] Construction equipment: The integrated paving and compaction system described in this application is used. The paving equipment is equipped with an adjustable auger distributor with a width of 6-12m. The distributor blades are made of HRC58-62 wear-resistant alloy steel, and both ends are equipped with 30cm long reverse auger blades. The upper reference screed of the double-layer composite screed has a vibration frequency of 25Hz and an amplitude of 1.0mm, while the lower high-frequency micro-vibration module has a frequency of 60Hz and an amplitude of 0.2mm. It is equipped with a 15W / cm² ceramic infrared heating module. The screed is preheated to a certain temperature before construction. Temperature ≥100℃; the compaction equipment is configured sequentially with a 12t double-drum vibratory roller, a 26t bump tire roller, and a 13t vibratory roller. The tire bumps have an isosceles trapezoidal cross section with an upper base width of 20mm, a lower base width of 40mm, a height of 30mm, a lateral spacing of 50mm, and a longitudinal spacing of 80mm, arranged in a staggered matrix. Five sets of infrared temperature sensor arrays are deployed along the entire line, with a temperature measurement range of 50~200℃ and a detection accuracy of ±1.5℃. All equipment is linked in real time through the main control PLC unit.

[0035] Base course pretreatment: Before construction, thoroughly clean the floating dust and loose debris from the cement-stabilized crushed stone base course. After the base course compaction, flatness, and deflection value are deemed qualified, evenly spray 0.3-0.5 L / m² of cationic emulsified asphalt tack coat. Allow it to stand for at least 2 hours until the emulsion is completely broken before proceeding with the paving operation.

[0036] Paving and pre-compaction: The paver moves continuously at a constant speed of 3m / min without stopping or changing speed at will. The auger distributor is always full of material. A material level sensor is placed every 1m in the transverse direction to adjust the material distribution speed in real time to ensure that the material level is uniform throughout the width. Gradient pre-compaction is completed by the two-stage vibration of the double-layer composite screed. After paving, the initial compaction degree of the mixture is ≥88%, and the transverse temperature difference is stably controlled within 8℃ throughout the width.

[0037] Differentiated grading and compaction: Strictly matching corresponding temperature windows for orderly operation: Initial compaction: When the internal temperature of the mixture is ≥150℃, a 12t double-drum vibratory roller is used with a 0.5mm amplitude and a 35Hz frequency, in a static pressure combined with a weak vibration mode for two passes, at a rolling speed of 3km / h, proceeding from the outer side of the road surface to the center, with adjacent wheel tracks overlapping by 1 / 3 of the wheel width. After the initial compaction, the compaction degree is ≥90%. Secondary compaction: When the internal temperature of the mixture is 120-140℃, a 26t block tire roller is used, the tire pressure is adjusted to 400kPa, and static compaction is performed 5 times at a speed of 4.5km / h. The spacing between the rollers should not exceed 10cm each time. After secondary compaction, the compaction degree of the bottom core sample should be ≥95%. Final compaction: When the internal temperature of the mixture is 90-110℃, a 13t vibratory roller is used with the vibratory wheel at a fixed angle of 15° to the direction of travel, and the roller is compacted twice at a frequency of 40Hz until the wheel tracks are completely eliminated. The final compaction temperature is ≥80℃.

[0038] Intelligent closed-loop temperature control: The main control PLC unit collects real-time transverse temperature data throughout the construction process. When the transverse temperature difference is detected to be greater than 10℃, the paver travel speed is automatically reduced by 0.5m / min, and the auger distributor speed is simultaneously increased by 15% until the transverse temperature difference is restored to within 8℃. When the temperature of the working section approaches the lower limit of the process, the corresponding roller is automatically linked to increase its travel speed to ensure that all compaction processes are completed within the standard temperature window.

[0039] Joint treatment: Longitudinal joints are paved using a double-machine echelon system with a 6m spacing between the front and rear pavers and a 20cm uncompacted overlap strip. When compacting across the joint, first compact the 15cm side of the already paved layer, then compact the 15cm side of the newly paved layer, repeating this process twice before merging into the main line compaction process. Transverse construction joints are cut into vertical and flat sections. After applying a tack coat of emulsified asphalt, the screed is preheated across the joint for 12 minutes to ensure that the internal temperature of the mixture at the joint is ≥150℃. After paving, the screed is compacted transversely three times before transitioning to longitudinal compaction.

[0040] Construction control: Throughout the entire process, road rollers are strictly prohibited from turning, making U-turns, or braking suddenly on hot, uncooled road surfaces. The emergency braking distance of the road roller must be ≥5m to avoid wavy deformation of the road surface.

[0041] After completion, the core sampling test results of this embodiment are as follows: the average compaction degree of the entire road surface is 97.1%, the minimum compaction degree of the bottom layer is 96.8%, the aggregate crushing rate is 2.6%, the maximum deviation of road surface smoothness is 1.8mm / 3m, and the structural depth, dynamic stability and residual stability are all better than the standard limits.

[0042] Example 2: Construction of a 16cm thick asphalt pavement under low temperature conditions This embodiment is applied to the construction of asphalt pavement on a first-class highway. The ambient temperature on site is 3℃ (low-temperature construction conditions below 5℃). The single-layer design paving thickness is 16cm, the paving width is 8m, and the construction length is 2km.

[0043] Raw materials and mix proportions: The mixture uses AC-25 dense grade SBS modified asphalt mixture with an asphalt-aggregate ratio of 4.6%. The mixing temperature of the mixture at the plant is 170-180℃, and the paving temperature at the site is ≥165℃. Equipment adaptation: The overall equipment layout is the same as in Example 1. The conventional vibratory roller is replaced with a 35-45Hz adjustable low-amplitude variable frequency vibratory roller with an amplitude of 0.2-0.4mm. Before construction, the preheating temperature of the screed is increased to 120℃, and the demulsification and standing time of the tack coat is appropriately extended to 3 hours. Construction parameter adjustments: The paver travel speed is adjusted to 2.5m / min, and the overall compaction temperature window is lowered by 20℃: the initial compaction window has an internal temperature of ≥135℃ for the mixture, the secondary compaction window has an internal temperature of 105~125℃ for the mixture, and the final compaction window has an internal temperature of 75~95℃ for the mixture. The remaining construction process, intelligent temperature control logic, and joint treatment process are consistent with those in Example 1.

[0044] The completion test results of this embodiment are as follows: the overall average compaction degree of the road surface is 97.0%, the minimum compaction degree of the bottom core sample is 96.5%, the aggregate breakage rate is 2.8%, the maximum deviation of flatness is 2.0mm / 3m, all indicators meet the requirements of the high-grade highway construction specifications, and the construction quality is stable and controllable under low temperature conditions.

[0045] Example 3: Construction of 20cm Thick Asphalt Pavement on Narrow Municipal Roads This embodiment is applied to the construction of a narrow municipal road with a paving width of 6m, a single-layer paving thickness of 20cm, an ambient temperature of 18℃, and the mixture is AC-30 dense-graded matrix asphalt mixture with an asphalt-aggregate ratio of 4.4%.

[0046] Equipment compatibility: The front-mounted double-drum vibratory roller is replaced with a front-steel and rear-rubber combined roller to adapt to the needs of narrow road sections, turns, and close-range construction operations; the parameters of the double-layer composite screed are set at the following range endpoints: the upper reference screed has a vibration frequency of 30Hz and an amplitude of 1.2mm, and the lower high-frequency micro-vibration module has a frequency of 70Hz and an amplitude of 0.3mm. Construction parameter adjustments: Paver travel speed 2m / min, initial compaction using a 10t front steel and rear rubber roller, amplitude 0.8mm, frequency 40Hz, 3 passes; secondary compaction using a 24t block tire roller, tire pressure 500kPa, 6 passes; final compaction using a 10t vibratory roller, vibratory wheel at a 20° angle to the travel direction, 3 passes; other intelligent temperature control and joint treatment processes remain consistent with Example 1.

[0047] The completion test results of this embodiment are as follows: the average compaction degree of the road surface is 96.9%, the minimum compaction degree of the bottom layer is 96.3%, the aggregate breakage rate is 2.9%, and the maximum deviation of the smoothness is 1.9mm / 3m, which verifies the good adaptability of this application to the upper limit of paving thickness and narrow construction scenarios.

[0048] Comparative example: Existing conventional thick single-layer paving process This comparative example uses the same construction section, the same raw materials, and the same 18cm design paving thickness as Example 1. It adopts the industry's conventional large-thickness paving process: single-layer paving with a regular paver, equipped with a 32t heavy-duty double steel wheel roller, high-frequency high-amplitude rolling process, no layered temperature matching process, no protrusion deep compaction structure, and no full-width real-time temperature closed-loop control.

[0049] The results of the comparative test upon completion showed that the highest compaction degree of the roadbed was only 94.2%, which could not meet the requirements of the high-grade highway specifications. The aggregate breakage rate was as high as 9.7%. The anti-skid structure depth of the road was insufficient. The maximum deviation of the flatness with a 3m straightedge was 4.2mm / 3m. The density of the joints was 2.1% lower than that of the main road surface. The overall construction period was 28% longer than that of Example 1, and the fuel consumption of the road roller was 26% higher.

[0050] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for paving and compacting thick asphalt pavement on high-grade highways, applicable to the construction of hot-mix asphalt pavement with a single-layer paving thickness of 16-20cm, wherein the hot-mix asphalt mixture is AC-25 or AC-30 dense-graded asphalt mixture, comprising the construction steps of hot-mix asphalt mixture paving and staged compaction, characterized in that... Includes the following steps: S1. Anti-segregation paving and two-stage gradient pre-compaction: A paver with a spiral distributor and a double-layer composite screed is used for continuous and uniform paving. The double-layer composite screed applies two-stage vibration with differences in frequency and amplitude to the paved mixture, forming a paving layer with an initial compaction degree of not less than 88% based on the maximum theoretical density. S2. Differentiated compaction based on temperature windows: Based on the viscosity-temperature characteristics of asphalt mixtures, three continuous temperature windows are divided according to the measured internal temperature of the mixture at 1 / 2 of the paving layer thickness: high-temperature initial compaction, medium-temperature intermediate compaction, and low-temperature final compaction. Vibratory compaction is used in the high-temperature initial compaction window to form a stable aggregate skeleton. In the medium-temperature intermediate compaction window, a pneumatic tire roller with trapezoidal protrusions is used to perform static compaction to achieve full-depth compaction of the paving layer. In the low-temperature final compaction window, oscillatory compaction is used to complete surface finishing and internal stress elimination. S3. Intelligent closed-loop temperature control: Real-time monitoring of the transverse temperature distribution of the paving layer along the paving width direction. When the temperature deviates from the preset threshold of the corresponding temperature window, the paver travel speed and / or the operating parameters of the compaction equipment are automatically adjusted to ensure that each compaction process is completed within the corresponding temperature window. S4. Synchronous compaction treatment of joints: For longitudinal joints and transverse construction joints, a special compaction process with matching temperature control is adopted to achieve the same compaction quality at the joints as that of the main road surface.

2. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 1, characterized in that, The double-layer composite screed in step S1 includes an upper reference screed and a lower high-frequency micro-amplitude vibration module; the vibration frequency of the upper reference screed is 20-30Hz and the amplitude is 0.8-1.2mm, and the vibration frequency of the lower high-frequency micro-amplitude vibration module is 50-70Hz and the amplitude is 0.1-0.3mm; the continuous uniform paving speed of the paver is 2-4m / min, and the temperature of the hot-mix asphalt mixture entering the paving site is 160-180℃.

3. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 1, characterized in that, The specific steps of differentiated compaction described in step S2 are as follows: Initial compaction process: In the high-temperature initial compaction window where the internal temperature of the mixture is not lower than 150℃, a double steel drum vibratory roller with a self-weight of 10-12t is used to statically compact or weakly vibrate for 1-3 passes with an amplitude of 0.3-0.8mm and a frequency of 30-40Hz, and the compaction speed is 2-3km / h. Secondary compaction process: In the medium-temperature secondary compaction window where the internal temperature of the mixture is 120-140℃, a block tire roller with a self-weight of 24-26t is used to statically compact the mixture 4-6 times with a tire inflation pressure of 300-500kPa and a compaction speed of 4-5km / h. Final compaction process: In the low-temperature final compaction window where the internal temperature of the mixture is 90-110℃, a vibratory roller with a self-weight of 10-13t is used to compact the mixture 2-3 times at a fixed angle of 10°-20° with the direction of travel until the wheel tracks are completely eliminated.

4. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 3, characterized in that, The bump-type tire roller used in the re-compaction process has bumps on the tire surface with an isosceles trapezoidal cross section. The bumps have an upper base width of 15-25mm, a lower base width of 35-45mm, and a height of 25-35mm. The bumps are arranged in a staggered matrix on the tire surface, with a lateral spacing of 40-60mm and a longitudinal spacing of 70-90mm between adjacent bumps.

5. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 1, characterized in that, The specific logic of the intelligent closed-loop temperature control in step S3 is as follows: when the maximum lateral temperature difference of the paving layer is detected to exceed 10℃, the paver travel speed is automatically reduced by 0.5 to 1 m / min, while the speed of the auger distributor is increased by 10% to 20% until the maximum lateral temperature difference of the paving layer recovers to within 8℃; when the temperature of the mixture in the working section is detected to be close to the lower limit of the corresponding temperature window, the corresponding compaction equipment is automatically linked to increase the rolling speed to ensure that the compaction process is completed within the temperature window.

6. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 1, characterized in that, The specific process for the synchronous compaction treatment of the joint in step S4 is as follows: For longitudinal joints, a double-machine echelon paving is used to form a hot joint. The echelon paving spacing is controlled at 5-8m, and a 20cm wide uncompacted overlap strip is reserved. A road roller is used to compact the joint across the joint. When compacting, the already paved layer side is compacted 10-15cm wide first, and the newly paved layer side is compacted 10-15cm wide second. For transverse construction joints, vertical flat joints are used. Before paving, emulsified asphalt tack coat is applied to the joint section, and the mixture at the joint is preheated by a screed to ensure that the internal temperature of the mixture at the joint is not lower than 150℃. After paving, the mixture is first rolled transversely three times, and then transitioned to normal longitudinal rolling.

7. The method for paving and compacting thick asphalt pavement on high-grade highways according to claim 3, characterized in that, When low-temperature construction is carried out at an ambient temperature below 5℃, the asphalt-aggregate ratio of the hot-mix asphalt mixture is 4.2% to 4.8%, and the paving entry temperature is not lower than 165℃; the internal temperature of the mixture in the initial compaction process is not lower than 135℃, the internal temperature of the mixture in the secondary compaction process is 105 to 125℃, and the internal temperature of the mixture in the final compaction process is 75 to 95℃. The final compaction uses a low-amplitude variable frequency vibratory roller with a frequency of 35 to 45Hz and an amplitude of 0.2 to 0.4mm.

8. An integrated paving and compaction system for implementing the paving and compaction method for thick asphalt pavement of high-grade highways as described in any one of claims 1 to 7, characterized in that, It includes a sequentially interconnected anti-segregation paving unit, a gradient compaction unit, and an intelligent monitoring and control unit; The anti-segregation paving unit includes a paver body, a auger distributor located at the rear of the paver body, and a double-layer composite screed. The auger distributor has reverse auger blades at both ends. The double-layer composite screed is configured to generate upper and lower layer vibrations with different frequencies and amplitudes to achieve two-stage gradient precompaction of the paving layer. The gradient compaction unit includes a front-mounted double-drum vibratory roller, a middle-mounted bump tire roller, and a rear-mounted vibratory roller that operate sequentially along the paving direction, respectively corresponding to the high-temperature initial compaction, medium-temperature secondary compaction, and low-temperature final compaction processes, and is used to achieve differentiated compaction based on temperature windows. The intelligent monitoring and control unit includes an array of infrared temperature sensors arranged along the paving width direction, and a main control PLC unit that is communicatively connected to the anti-segregation paving unit and the gradient compaction unit. The main control PLC unit has preset control logic, which is configured to generate and send a travel speed adjustment command or a compaction parameter adjustment command to the anti-segregation paving unit and / or the gradient compaction unit when it is determined that adjustment is required based on the transverse temperature data of the paving layer collected by the infrared temperature sensor array.

9. The integrated paving and compaction system according to claim 8, characterized in that, The infrared temperature sensor array includes at least five sets of sensors, which are respectively arranged at the discharge port of the spiral distributor, the rear edge of the double-layer composite screed, the starting point of the initial pressing process, the starting point of the secondary pressing process, and the starting point of the final pressing process; the spacing between the measuring points of each set of sensors along the paving width direction is no more than 0.5m, the temperature measurement range is 50~200℃, and the detection accuracy is no less than ±1.5℃; The rear-mounted vibratory roller can be replaced by a low-amplitude variable frequency vibratory roller. The low-amplitude variable frequency vibratory roller has a vibration frequency of 35-45Hz and an amplitude of 0.2-0.4mm, and is used in low-temperature construction scenarios where the ambient temperature is below 5℃. The self-weight of the centrally mounted bump tire roller is 24-26t, and the tire inflation pressure is adjustable from 300 to 500kPa. The cross-section of the bumps on the tire surface is an isosceles trapezoid with an upper base width of 15-25mm, a lower base width of 35-45mm, and a height of 25-35mm. The bumps are arranged in a staggered matrix on the tire surface.

10. The integrated paving and compaction system according to claim 8, characterized in that, The double-layer composite ironing board includes an upper reference ironing board and a lower high-frequency micro-amplitude vibration module; the upper reference ironing board has a vibration frequency of 20-30Hz and an amplitude of 0.8-1.2mm, and the lower high-frequency micro-amplitude vibration module has a vibration frequency of 50-70Hz and an amplitude of 0.1-0.3mm; the double-layer composite ironing board is also equipped with a ceramic infrared heating module with a power density of not less than 15W / cm².

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