Thin-layer asphalt concrete construction method

Abstract

The invention relates to a thin-layer asphalt concrete construction method, and belongs to the technical field of asphalt concrete pavement in road engineering. In order to solve the technical problems that according to a traditional construction technology, the compactness at a joint is insufficient, interlayer bonding force is poor, and the compactness is not up to the standard due to unbalanced temperature control, a continuous bonding film is formed through base layer pretreatment and an accurate emulsified asphalt spraying technology, and structure densification is achieved through a temperature control paving and combined type compacting technology; wherein a double-steel-wheel road roller is used for performing static pressure twice in the initial pressing process, a high-frequency low-amplitude vibratory road roller is used for performing rolling compaction for three times in the re-pressing process, a pneumatic tire road roller is used for eliminating wheel marks in the final pressing process, the interface continuity is ensured through an innovative joint treatment technology, a slant joint crossing rolling compaction mode is adopted for longitudinal joints, and a precise cutting and lap joint process is implemented for transverse joints. The method can effectively improve the integrity, the skid resistance and the durability of the pavement structure, and is particularly suitable for thin overlays and preventive maintenance projects of municipal roads and expressways.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt concrete paving for road engineering. More specifically, the present invention relates to a construction method for thin-layer asphalt concrete. Background Art

[0002] In the technical field of thin-layer paving of asphalt concrete, there are several key problems in the actual application of traditional construction processes that affect the pavement quality. First of all, insufficient interlayer bonding performance is likely to cause the surface layer to separate from the base layer. The main reason is that the pretreatment of the base layer surface is not thorough or the emulsified asphalt spraying process control is improper. In the conventional spraying operation, the distribution uniformity of the emulsified asphalt is poor. Excessive spraying in local areas is likely to form flowing accumulations, while insufficient spraying is difficult to form a complete bonding film, resulting in an increase in the discreteness of the interfacial bonding force. At the same time, the demulsification time of the emulsified asphalt is closely related to the environmental temperature and humidity. If the static time is insufficient or too long, it may affect the synergistic effect between the bonding layer and the mixture, thereby triggering the risk of interfacial slip.

[0003] Secondly, the defects in the joint treatment process are the main inducement for the weak links in the thin-layer paving structure. Longitudinal joints often result in loose bonding of new and old mixtures due to the temperature difference between adjacent paving sections. The traditional rolling method is difficult to eliminate the sudden change in void ratio at the joint. When dealing with transverse joints, the conventional cutting method is likely to leave loose mixtures, and the deviation in the perpendicularity of the joint interface will cause the overlapping of new and old materials to be not tight. In addition, the compaction energy transfer efficiency in the joint area is low, and the conventional rolling path is likely to cause the mixture to be pushed, exacerbating the aggregate crushing and grading segregation at the interface. The root cause of these problems lies in the inaccurate control of the geometric shape of the joint interface and the insufficient management of the temperature gradient of the hot mixture.

[0004] Thirdly, the poor matching of the paving and compaction process parameters directly affects the density and uniformity of the thin-layer structure. The lack of coordination between the paving speed and temperature control is likely to cause uneven distribution of the internal temperature field of the mixture. When the paving speed is too fast, the temperature at the front end of the mixture drops suddenly, resulting in a delay in the initial compaction time and affecting the effective rolling time. In the traditional compaction process, the combination of rollers and compaction parameters (such as amplitude, frequency, and traveling speed) lack scientific adaptation. Excessive vibration of the single-drum roller is likely to cause damage to the surface texture of the thin layer, while improper final compaction timing of the tire roller may result in wheel marks that are difficult to eliminate. Especially for thin-layer structures with a thickness less than 3 cm, the existing processes are difficult to balance the contradiction between improving density and maintaining surface flatness.

[0005] In addition, the temperature sensitivity problem runs through the entire construction process. The temperature decay curve of the mixture from paving to final compaction is significantly affected by environmental factors. When the paving temperature is lower than the critical value, the compacting time window of the mixture shortens, resulting in both insufficient compaction passes and over-compaction. Especially in the recompaction stage, if the temperature of the mixture has dropped below the optimal compaction range, vibration compaction will instead damage the formed skeleton structure. The existing technology has limited real-time control capabilities for temperature monitoring and process connection, making it difficult to achieve dynamic matching between the temperature field and mechanical operations.

[0006] The breakthrough of these technical bottlenecks has long been limited by the insufficient precision of multi-process collaborative control: First, the interlayer bonding quality is affected by the coupling of multiple variables such as spraying process, base layer condition, and environmental conditions, and it is difficult for traditional single-factor control methods to achieve stable output; second, the state of the mixture at the joint has spatio-temporal differences, and conventional construction equipment lacks a dedicated joint treatment function module for the characteristics of thin layers; third, the heat dissipation rate of the thin-layer mixture is faster than that of conventional thickness pavements, and the existing temperature control system has insufficient adaptability to the construction rhythm. These problems jointly restrict the improvement of the overall performance of the thin-layer pavement structure, and there is an urgent need to achieve refined collaborative control of key technical parameters through process innovation. Summary of the Invention

[0007] The object of the present invention is to provide a construction method for thin-layer asphalt concrete to solve at least the above problems.

[0008] In order to achieve the objectives and other advantages of the present invention, a construction method for thin-layer asphalt concrete is provided, including: Step 1, pre-treat the surface of the base course, then evenly spray an emulsified asphalt bonding layer on the surface of the base course. The spraying amount of the emulsified asphalt is 0.3 - 0.4 kg / m². After spraying, let it stand for 30 - 40 minutes to form a continuous bonding film; Step 2, use a paver to pave the thin-layer asphalt concrete mixture. During paving, control the paving temperature of the mixture to be not lower than 155 °C, the walking speed of the paver is 2.5 - 3.5 m / min, and the paving thickness deviation does not exceed ±2 mm; Step 3, use a combined compaction process to densify the paved layer. In the initial compaction stage, use a 10-ton double-drum roller to roll along the paving direction in a static pressure mode for 2 passes. During rolling, spray atomized water on the surface of the steel wheels to prevent the mixture from sticking to the wheels. At the end of the initial compaction, the surface temperature of the mixture is not lower than 135 °C. In the re-compaction stage, use a 12-ton vibratory roller to roll in a high-frequency and low-amplitude mode for 3 passes. The vibration frequency is set at 40 Hz and the amplitude is set at 0.8 mm. In the final compaction stage, use a 16-ton tire roller to roll at a speed of 6 km / h for 2 passes. After the final compaction, detect the degree of compaction and control the degree of compaction to reach more than 97% of the maximum theoretical density; Step 4, reserve an uncompacted mixture width of 15 cm at the longitudinal joint. During subsequent paving, use the hot joint method to overlap the newly paved mixture with the reserved uncompacted mixture by 5 cm. The overlapping area is rolled across the joint at an angle of 45 degrees by a double-drum roller. At the transverse joint, use a cutting machine to vertically cut off the loose mixture at the end. After the cutting surface is coated with emulsified asphalt, then pave the new mixture. When paving the new mixture, it extends 20 cm beyond the cutting line and is trimmed to be flush by hand. Preferably, the pre-treatment of the surface of the base course includes: using a high-pressure water gun to remove the floating dust and loose particles on the surface of the base course, using a hot air device to dry the surface of the base course until the moisture content is less than 3%, using a 3-meter straightedge to detect the flatness of the surface of the base course and mark the sunken areas. The areas where the sunken depth exceeds 3 mm are filled with hot asphalt mixture until they are flush with the surrounding areas. After filling, use a double-drum roller to roll at a walking speed of 2 km / h for 3 passes.

[0009] Preferably, during paving, the paving temperature of the mixture is controlled to be not lower than 155 °C, including: after the mixture arrives at the construction site, an infrared thermometer is used to detect the temperature at three points, namely the front, middle, and rear of each truckload of the mixture before unloading. The front point is at the top of the material pile 0.8 - 1 m from the tail of the carriage, the middle point is in the middle of the material pile at half of the carriage length, and the rear point is at the bottom of the material pile 0.6 - 0.8 m from the front of the carriage; when the detected temperature at any one of the points is lower than 160 °C, the emergency paving procedure is started, the walking speed of the paver is increased to the upper limit value of 3.5 m / min, and the heating system of the paver is started to raise the temperature of the screed to 120 - 130 °C. At the same time, the vibration rammer frequency is increased from 25 Hz to 30 Hz; when the detected temperature at any one of the points is lower than 155 °C, it is determined as unqualified mixture and is discarded.

[0010] Preferably, an ultrasonic thickness sensor is installed under the screed of the paver. The ultrasonic thickness sensor collects paving thickness data every 1 m and compares it with the preset thickness data. When the deviation exceeds ±2 mm, the hydraulic servo mechanism is controlled by the paver control system to adjust the elevation angle of the screed at an angular velocity of 0.05° / s. At the same time, the impact force of the vibration rammer is adjusted to 105% - 120% of the set value.

[0011] Preferably, in the initial compaction stage, a atomized water spraying system is arranged along the length above the steel wheels of the tandem roller. The atomized water spraying system atomizes with a compressed air pressure of 0.25 - 0.35 MPa, the spraying flow rate is controlled at 0.8 - 1.2 L / min, the particle size of the atomized water droplets is 50 - 150 μm, and the spraying angle forms an angle of 45 - 60° with respect to the tangent direction of the steel wheel; the rolling speed gradient of the tandem roller is controlled within the range of 1.5 - 2.5 m / min, and the overlapping width of adjacent rolling belts is 1 / 3 - 1 / 2 of the steel wheel width; the Ra value of the steel wheel surface roughness is maintained within the range of 6.3 - 12.5 μm, and the surface void ratio of the mixture after initial compaction is controlled between 7.5% - 8.5%.

[0012] Preferably, the double-wheel roller is equipped with a temperature field uniformity control system, which includes an array of infrared temperature measurement modules symmetrically distributed along the axis of the steel wheel, each temperature measurement module includes multiple detection units, and the spacing between adjacent detection units is 15-20 cm. Each temperature measurement module collects the surface temperature data of the mixture in a grid of 0.5 m × 0.5 m in the width direction in real time; the temperature field uniformity control system has a built-in temperature difference gradient calculator. When the temperature difference gradient of three consecutive grid units along the rolling direction exceeds 2°C / m, the servo controller of the travel motor of the double-wheel roller is triggered, and the temperature is adjusted according to ΔV=0.1×(ΔT-15) The rolling speed of the double steel wheel roller is dynamically adjusted by 100m / min, where ΔT is the maximum temperature difference measured in three consecutive grid units. The spiral water channel cooling system inside the steel wheel is simultaneously activated during the adjustment process to maintain the working temperature of the steel wheel within the range of 50±3℃. The temperature field uniformity control system is also equipped with a temperature control compensation module. When the ambient temperature is greater than 35℃, the initial rolling speed reference value is automatically reduced by 0.2-0.5m / min and the atomized water spray flow rate is increased by 15%-20%.

[0013] Preferably, during the re-compacting stage, a 12-ton vibratory roller is used to roll the vibratory wheel at an offset angle of 5°-8° to the travel direction, the overlapping width of adjacent rolling belts is 1 / 4-1 / 3 of the width of the vibratory wheel, and the phase angle of the vibratory wheel is switched at 60° intervals during each rolling. During the re-compacting stage, an electromagnetic field generator is synchronously started, the electromagnetic field generator is fixed to the frame of the vibratory roller through a mounting bracket and is located 0.3-0.5 meters in front of the vibratory wheel, and a 50-100 Hz alternating magnetic field is applied in front of the vibratory wheel through the electromagnetic field generator, and the magnetic field strength is 0.3-0.5 T, so that the needle-like flake aggregates in the mixture are oriented along the rolling direction.

[0014] Preferably, in the final pressure stage, the dynamic control range of the internal pressure of the tire of the 16-ton tire roller is 0.5-0.8MPa, the control step is ≤0.02MPa, and the surface temperature of the mixture satisfies: P =0.7+0.015( T s -80), where P is the tire pressure in MPa, T s is the mixture surface temperature, T s ≥60℃, take the numerical value.

[0015] Preferably, in the longitudinal joint treatment, when paving the new mixture, the temperature of the mixture within 10 cm of the joint side is controlled at 155 - 160 °C during paving, and the surface of the reserved uncompacted mixture is preheated to 110 - 120 °C, with the temperature difference between the two ≤ 40 °C; during cross - joint rolling, the tandem roller operates in two stages. In the first stage, it statically compresses at a 45° oblique angle for 2 passes, with a rolling speed of 1.5 - 2.0 m / min. In the second stage, it switches to vibratory rolling at a 30° oblique angle for 1 pass, with a vibration frequency of 25 Hz and an amplitude of 0.4 mm; 0.6% - 0.8% of nano - montmorillonite modified asphalt is incorporated into the mixture within a depth of 3 cm from the surface layer of the reserved uncompacted mixture.

[0016] Preferably, in the transverse joint treatment, the cutting depth reaches 5 - 8 mm below the lower boundary of the loose layer, and the Ra value of the cutting surface roughness is controlled at 3.2 - 6.3 μm; the emulsified asphalt applied is mixed with 0.3% - 0.5% of carbon nanotube toughening agent, and the coating amount is calculated according to the formula: Q =0.4 + 0.02( T a - 20), where, Q is the coating amount, with the unit of kg / m 2 , T a is the ambient temperature, with the unit of °C, taking the numerical value.

[0017] The present invention has at least the following beneficial effects: First, by defining the base course pretreatment, precisely spraying the emulsified asphalt bonding layer and the combined compaction process parameters, the continuity of the interlayer bonding film and the density of the paving layer are ensured. Controlling the matching of the paving temperature and speed reduces the abnormal void ratio caused by temperature segregation; the innovative joint treatment process can effectively eliminate the concentration of interfacial shear stress. The oblique rolling of the longitudinal joint reduces the risk of aggregate misalignment, and the precise cutting of the transverse joint avoids the residue of loose materials. The synergistic effect of the technical parameters enables the thin - layer structure to reach more than 97% of the theoretical density, significantly improving the anti - skid performance and anti - fatigue characteristics. Second, through the combined pretreatment process of the high - pressure water gun and the hot - air equipment, the floating dust on the base course is thoroughly removed and the moisture content is controlled, eliminating the interference of the interfacial water film; the 3 - meter straightedge detection is combined with filling the depression with hot asphalt to ensure that the flatness of the base course ≤ 3 mm, avoiding the reflection cracks caused by stress concentration after thin - layer paving. The tandem roller slowly rolls the filling area to ensure that the repaired material is interlocked and compacted with the base course, creating an ideal base surface condition for the subsequent uniform spraying of the bonding layer. Third, through the three - point temperature detection strategy, the temperature gradient of the mixture is accurately identified to avoid the entry of locally low - temperature materials into the paving process; the emergency paving procedure maximizes the salvage of the compactability of the mixture at the critical temperature by increasing the paving speed, heating the screed plate and adjusting the rammer frequency, reducing the waste rate. The temperature threshold determination standard can prevent the unqualified mixture from damaging the interlayer thermal bond, ensuring the uniformity of the initial density of the paving layer. Fourth, the dynamic deviation correction of paving thickness is achieved through real-time monitoring and closed-loop control of ultrasonic thickness sensors, and the ±2mm precision control is superior to conventional manual detection methods. The hydraulic servo mechanism and the vibration rammer joint adjustment mechanism simultaneously optimize the paving layer thickness and initial density, reduce the thickness fluctuation caused by uneven base, and create a uniform compaction foundation for subsequent rolling processes. Fifth, the optimization of the parameters of the atomized water spray system can form a uniform water film to avoid the surface texture damage caused by the steel wheel sticking to the material; the rolling speed gradient and overlapping width control ensure the uniform transmission of the initial pressure energy, and the steel wheel roughness limit ensures effective shearing. The setting of the surface porosity of 7.5%-8.5% reserves reasonable space for the reconstruction of aggregates in the re-compacting stage to avoid aggregate crushing caused by excessive compaction. Sixth, the array-type infrared temperature measurement module is used to realize the digital analysis of the temperature field in the rolling area, and the temperature gradient feedback controls the rolling speed and steel wheel temperature to avoid local overpressure or underpressure. The temperature control compensation module dynamically adjusts the process parameters according to the ambient temperature, significantly reducing the risk of mixture sticking to the wheel and cold shrinkage cracking in high temperature environments, and improving the adaptability to complex working conditions. Seventh, the vibration energy propagation direction is optimized through the vibration wheel offset angle and phase angle switching technology to reduce the aggregate directional arrangement defects caused by unidirectional rolling; the alternating magnetic field induces the directional arrangement of needle-shaped aggregates, enhances the embedded skeleton structure of the mixture, makes the void distribution more uniform after re-compaction, and improves the anti-rutting ability and load transfer efficiency. Eighth, the dynamic correlation formula between tire pressure and mixture temperature (P=0.7+0.015 (Ts-80)) is used to scientifically match the viscoelasticity of the material at the final pressure stage, and the tire ground pressure is adaptively adjusted to eliminate wheel marks. The pressure control step length is ≤0.02MPa to ensure smooth transition of pressure changes and avoid secondary damage to surface texture caused by sudden pressure changes. Ninth, the interface between the new and old mixtures is effectively integrated through the temperature gradient control on the joint side (temperature difference ≤ 40°C) and the two-stage oblique rolling strategy. Nano-montmorillonite modified asphalt improves the thermal stability of the reserved mixture and prevents aggregate displacement during cross-joint rolling. The phased rolling parameter design balances the density requirements and interface shear protection to ensure that the shear strength of the joint area is ≥1.5MPa. Tenth, the weakened layer is completely removed by cutting to a depth of 5-8mm below the lower boundary of the loose layer, and the rough interface of Ra=3.2-6.3μm enhances the bonding effect of emulsified asphalt. The carbon nanotube toughening agent improves the crack resistance of the emulsified asphalt film, and the coating amount formula (Q=0.4+0.02(Ta-20)) realizes adaptive control of ambient temperature, ensuring that the joint bonding strength attenuation rate is ≤15% in the temperature range of -10℃ to 40℃.

[0018] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. Detailed implementation manners

[0019] The following further describes the present invention in detail with reference to embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0020] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained from commercial channels.

[0021] An embodiment of the present invention provides a construction method for thin-layer asphalt concrete, including: Step 1, pretreat the surface of the base course, and then evenly spray an emulsified asphalt bonding layer on the surface of the base course. The spraying amount of the emulsified asphalt is 0.3 - 0.4 kg / m². After spraying, let it stand for 30 - 40 minutes to form a continuous bonding film; Step 2, use a paver to pave the thin-layer asphalt concrete mixture. During paving, control the paving temperature of the mixture to be not lower than 155 °C, the walking speed of the paver is 2.5 - 3.5 m / min, and the paving thickness deviation does not exceed ±2 mm; Step 3, use a combined compaction process to densify the paved layer. In the initial compaction stage, use a 10-ton double-drum roller to roll along the paving direction in a static pressure mode for 2 passes. When rolling, spray atomized water on the surface of the steel wheel to prevent the mixture from sticking to the wheel. The surface temperature of the mixture at the end of the initial compaction is not lower than 135 °C. In the re-compaction stage, use a 12-ton vibratory roller to roll in a high-frequency and low-amplitude mode for 3 passes. The vibration frequency is set to 40 Hz and the amplitude is set to 0.8 mm. In the final compaction stage, use a 16-ton tire roller to roll at a speed of 6 km / h for 2 passes. After the final compaction is completed, detect the degree of compaction and control the degree of compaction to reach more than 97% of the maximum theoretical density; Step 4, reserve an uncompacted mixture width of 15 cm at the longitudinal joint. During subsequent paving, use a hot joint method to overlap the newly paved mixture with the reserved uncompacted mixture by 5 cm. The overlapping area is rolled across the joint at an oblique angle of 45° with a double-drum roller. At the transverse joint, use a cutting machine to vertically cut off the loose mixture at the end. After the cutting surface is coated with emulsified asphalt, then pave the new mixture. When paving the new mixture, it extends 20 cm beyond the cutting line and is trimmed to be flush by hand. In the above embodiments, the spraying amount of emulsified asphalt can be selected as 0.3 kg / m², 0.35 kg / m² or 0.4 kg / m². The spraying equipment can be an asphalt distributor, such as the CCCC Xi'an Road Construction MS9B intelligent asphalt distributor, and the height of its spraying bar can be adjusted to 20 - 30 cm from the surface of the base course. The emulsified asphalt material can be selected as CRS-1 type cationic emulsified asphalt or CSS-1h type slow-setting and quick-hardening emulsified asphalt. The standing time can be selected as 30 minutes, 35 minutes or 40 minutes, and the specific duration is adjusted according to the ambient temperature. When the temperature is lower than 15°C, it is extended to 40 minutes, and when it is higher than 25°C, it is shortened to 30 minutes. During the construction process, before the spraying operation, a 3-meter straightedge is used to detect the flatness of the base course. The filling material for the sunken area can be selected as AC-10 type fine-grained hot mix asphalt mixture. In the above embodiments, the paving temperature is controlled to be not lower than 155°C. When detecting, a Raytek MI3 series infrared thermometer can be used, and the temperature measurement point is located on the surface of the mixture in the middle of the paver hopper. The walking speed of the paver can be selected as 2.5 m / min, 3.0 m / min or 3.5 m / min, and the specific speed is adjusted according to the supply amount of the mixture. For example, the Vögele SUPER 1880-3L paver can meet the above speed range. The thickness deviation control can be achieved through the automatic leveling system of the paver screed. For example, a MOBA company MMS 300E non-contact thickness sensor is used, which is installed on the rear bracket of the screed and feeds back data to the console in real time. The allowable deviation of the paving thickness is +2 mm or -2 mm. When the detected value exceeds the limit, the operator needs to manually fine-tune the elevation angle of the screed. In the above embodiments, in the initial compaction stage, a Dynapac CC6200 type double-drum roller can be selected, its drum width is 2130 mm, the number of static compaction passes is 2, and the compaction speed can be set as 1.8 m / min or 2.2 m / min. In the re-compaction stage, a XCMG XS223JE type vibratory roller can be selected, the vibration frequency is set as 40 Hz, the amplitude is 0.8 mm, and the compaction speed is controlled at 3.0 - 4.0 km / h. In the final compaction stage, a Sany SPR300-5 type pneumatic-tyred roller can be selected, the inner pressure of the tyre is set as 0.6 MPa, and the compaction speed is 6 km / h. In the temperature control, the surface temperature at the end of the initial compaction is not lower than 135°C, and a FLIR T540 infrared thermal imager can be used for multi-point detection, and the distance between the measurement points is 1.5 m × 1.5 m. For the compaction degree detection, a nuclear densitometer can be selected, such as the Troxler 3440 type, and the distance between the measurement points arranged longitudinally is 5 m and transversely 3 points. In the above embodiment, the width of the uncompacted mixture reserved in the longitudinal joint is 15 cm, and the width of the overlapping area is 5 cm. The Dynapac CC6200 double-wheel roller is used for rolling, the oblique rolling angle is 45°, and the rolling speed is controlled at 1.5-2.0 m / min. The cutting depth of the transverse joint is 5 mm or 8 mm below the lower limit of the loose layer. The cutting machine can be Wacker Neuson TS760, and the blade thickness is 3.2 mm. When the cutting surface is coated with emulsified asphalt, the coating amount is calculated according to the ambient temperature according to the formula Q=0.4+0.02 (Ta-20). For example, when Ta=25°C, the coating amount is 0.5 kg / m². After the new mixture is spread beyond the cutting line by 20 cm, a long-handled scraper and a hot tamping hammer combination tool are used for manual finishing, and the tamping hammer temperature is maintained at 120-130°C. By defining the technical details of base treatment, paving parameters, compaction process and joint treatment, it is possible to achieve uniform paving and high-density molding of thin-layer asphalt concrete. Limiting the spraying of emulsified asphalt and the control of the standing time can form a continuous bonding film and reduce the risk of interlayer peeling. The parameter matching of the combined compaction process can balance the density and surface flatness to avoid over-pressure or under-pressure. The joint treatment process effectively eliminates the problem of loose interface and improves the durability of the joint area through oblique rolling and precise cutting.

[0022] In another embodiment of the present invention, the surface of the base layer is pretreated, including: using a high-pressure water gun to remove floating dust and loose particles on the surface of the base layer, using hot air equipment to dry the surface of the base layer until the moisture content is less than 3%, using a 3-meter ruler to detect the flatness of the surface of the base layer and mark the depressed areas, and filling the depressed areas with a hot asphalt mixture until they are flush with the surrounding area. After filling, a double steel wheel roller is used to roll the area three times at a travel speed of 2 km / h.

[0023] In the above embodiment, the working pressure of the high-pressure water gun can be selected to be 8-12MPa, the nozzle diameter can be selected to be 2.5-3.0mm, and the spray angle can be adjusted to 30°-45°. The equipment can be selected from the Karcher HD 5 / 15 C high-pressure cleaner, whose maximum pressure is 15MPa. During operation, the nozzle is kept 30-40cm away from the surface of the base layer, and moves at a uniform speed in the horizontal direction, with a moving speed of 0.5-1.0m / s. The particle size of the residual particles on the surface of the base layer after cleaning must be less than 2mm. A similar process includes the use of a rotating brush cleaning device instead of a high-pressure water gun, but it needs to be combined with a vacuum cleaning system to recover debris. After cleaning, the surface needs to be visually inspected for visible loose objects, and compressed air is used to assist in blowing if necessary.

[0024] In the above-described embodiment, the outlet temperature of the hot air device is set to 120 - 150 °C, and the wind speed is controlled to be 15 - 20 m / s. A Leister LE 5000 HT hot air gun equipped with a temperature feedback control system can be selected for the device. During the drying operation, the hot air gun is 20 - 30 cm away from the surface of the base layer and reciprocally moves longitudinally at a speed of 1.0 - 1.5 m / min. Moisture content detection can be carried out using a portable humidity meter (such as Testo 606 - 2 type), with one measurement point arranged per 10 ㎡, and the sampling depth is 5 mm. When the ambient humidity > 80%, the drying time is extended to 1.2 times the reference value. A similar process includes using an infrared heating panel for radiant drying, but the heating distance needs to be controlled ≥ 50 cm to avoid overheating of the base layer.

[0025] In the above-described embodiment, during the 3 - meter straightedge test, the area where the gap between the straightedge and the base layer exceeds 3 mm is marked as the sunken area. AC - 10 type hot mix asphalt mixture can be selected as the filling material, and the discharge temperature is not lower than 150 °C. Before filling, emulsified asphalt (CRS - 1 type) needs to be applied to the edge of the sunken area, and the coating amount is 0.2 kg / m². A Dynapac CC6200 type tandem roller can be selected, with a steel wheel width of 2130 mm, a fixed rolling speed of 2 km / h, and an overlap of 1 / 2 wheel width between adjacent rolling bands. After rolling, the 3 - meter straightedge is used for re - measurement, and the height difference between the filled area and the surrounding area needs to be ≤ 1 mm. A similar process includes using polymer - modified asphalt mortar for filling, but an additional 30 - minute curing time is required.

[0026] Cleaning with a high - pressure water gun can effectively remove the dust and loose particles attached to the surface of the base layer, avoiding the formation of an isolation layer of impurities between layers. After cleaning, the cleanliness of the base layer surface is improved, providing a uniform attachment base for subsequent spraying of emulsified asphalt and reducing the problem of local weakness of the bonding film caused by particle residue. The hot air drying process precisely controls the moisture content of the base layer, eliminating the adverse effects of moisture on the demulsification process of emulsified asphalt. A base layer with a moisture content lower than 3% can ensure full contact between the bonding layer and the base layer, avoiding the formation of air pockets or interfacial slippage after water evaporation. Through the 3 - meter straightedge test and the sunken area filling process, the flatness error of the base layer surface can be controlled within 3 mm, reducing the thickness deviation and stress concentration after thin - layer paving. The filling of hot asphalt mixture combined with the low - speed rolling process ensures the dense interlock of the repaired area with the surrounding base layer, avoiding early damage to the paving layer caused by local depressions. The requirement of re - measuring the flatness after filling further guarantees the overall uniformity of the base layer, providing a stable foundation for subsequent construction.

[0027] In another embodiment of the present invention, during paving, the paving temperature of the mixture is controlled to be not less than 155 degrees Celsius, including: after the mixture arrives at the construction site, an infrared thermometer is used to detect the temperature of three points at the front, middle and rear of each truck of the mixture before unloading, the front point is located at the top of the material pile 0.8-1m away from the rear of the car, the middle point is located in the middle of the material pile at 1 / 2 of the length of the car, and the rear point is located at the bottom of the material pile 0.6-0.8m away from the front of the car; when the detected temperature at any point is lower than 160 degrees Celsius, the emergency paving program is started, the travel speed of the paver is increased to the upper limit of 3.5 meters / minute, and the heating system of the paver is started to raise the temperature of the ironing plate to 120-130°C, and the frequency of the vibrating hammer is increased from 25Hz to 30Hz; when the detected temperature at any point is lower than 155 degrees Celsius, it is determined to be an unqualified mixture and is discarded.

[0028] In the above embodiment, the mixture temperature detection can use the Leitai MI3 series infrared thermometer, and the detection points include the top of the pile at 0.8m and 1.0m from the rear of the car, the middle of the pile at 1 / 2 of the length of the car, and the bottom of the pile at 0.6m and 0.7m from the front of the car. The detection time for each point does not exceed 3 seconds, and the thermometer is 10-15cm away from the surface of the pile. The equipment can be installed on the bracket above the discharge port, and the bracket height can be adjusted from 1.2 to 1.8m. A similar process includes the use of thermocouple insertion detection, but the sensor needs to be embedded before the mixture is discharged. The detection data is transmitted to the control terminal in real time, and an audible and visual alarm is triggered when the temperature at any point is lower than 160°C. In the above embodiment, when the emergency paving program is started, the travel speed of the paver can be increased to an upper limit of 3.0m / min, 3.3m / min or 3.5m / min. The heating temperature of the screed plate can be set to 120℃, 125℃ or 130℃, and the heating power is adjusted to 110%-120% of the rated value. The frequency of the vibrating hammer can be increased from 25Hz to 28Hz, 30Hz or 32Hz, and the impact force increase is controlled at 5%-10%. A similar process includes covering the hopper with an auxiliary heating blanket, but it is necessary to ensure that the distance between the heating blanket and the mixture is ≥20cm. The paver control system can use the Vögele SUPER 1880-3L model, which has a speed adjustment accuracy of ±0.1m / min and a temperature control error of ≤±2℃. In the above-described embodiment, the determination threshold for the temperature of the mixture is 155°C. When the temperature at any point is lower than this value, the operator needs to record the vehicle number, the detection time, and the temperature value. The unqualified mixture can be transported to the waste area, which is ≥50 m away from the paving operation surface and covered with heat-insulating tarpaulins. The disposal of the waste materials can be entrusted to a third-party recycling enterprise, and the transport vehicle needs to be equipped with a temperature monitoring device to ensure that the temperature of the materials during transportation is <90°C. A similar process includes using the mixture with the critical temperature for non-structural layer paving, but it needs to be approved in writing by the supervision unit. The temperature data record sheet needs to include the detection points, time, temperature values, and the signatures of the operators, and the filing period is not less than 3 years. Through the three-point temperature detection strategy, the problem of uneven temperature distribution of the mixture can be effectively identified, and the entry of locally low-temperature materials into the paving link can be avoided. The dynamic adjustment of the emergency procedure parameters maximally retains the compactability of the mixture and reduces material waste. The clear criteria for determining unqualified materials and the treatment process ensure the traceability of the construction quality and prevent the damage of low-temperature materials to the interlayer bonding performance. Finally, the paving temperature is stably higher than 155°C, ensuring the uniformity of the initial density of the thin-layer structure.

[0029] In another embodiment of the present invention, an ultrasonic thickness sensor is installed under the screed of the paver. The ultrasonic thickness sensor collects the paving thickness data every 1 meter and compares it with the preset thickness data. When the deviation exceeds ±2 mm, the hydraulic servo mechanism is controlled by the paver control system to adjust the elevation angle of the screed at an angular velocity of 0.05° / s. At the same time, the impact force of the vibrating rammer is adjusted to 105%-120% of the set value.

[0030] In the above-described embodiment, the ultrasonic thickness sensor can select the MMS 300E non-contact sensor of MOBA Company and is installed on the rear bracket of the paver screed, 30-50 cm away from the end of the screed. The sensor is vertically pointed at the surface of the paving layer, and the installation height adjustment range is 10-20 cm. The data collection frequency can be set to 1 time per second or once every 1 meter. The device is powered by a 24V DC power supply, and the signal is transmitted to the console through a shielded cable. A similar process includes using a laser distance sensor to replace the ultrasonic sensor, but data drift in a strong light environment needs to be avoided. The sensor bracket can be equipped with a shock-absorbing device to reduce the impact of the paver vibration on the measurement accuracy. In the above embodiment, the preset thickness data can be input as the design value ±2mm deviation threshold set to +2mm or -2mm. When the detected thickness exceeds the threshold, the paver control system can control the hydraulic servo mechanism to adjust the screed elevation angle at an angular velocity of 0.03° / s, 0.05° / s or 0.07° / s. The impact force of the vibrating hammer can be adjusted to 105%, 110% or 120% of the set value, and the impact force setting value is set to 5kN-8kN according to the type of mixture. A similar process includes using a PID algorithm to optimize the elevation adjustment response speed, but the relationship between the hydraulic cylinder stroke and the elevation change needs to be calibrated in advance. The control signal transmission delay needs to be less than 0.5 seconds to ensure the effectiveness of real-time correction. In the above implementation, sensor calibration is required before paving: place a standard thickness block (10mm, 20mm, 30mm) on a flat steel plate, and adjust the sensor output value to a value ≤±0.5mm from the actual thickness. The hydraulic servo mechanism can use the Bosch Rexroth series, with a position repeatability of ±0.1mm. Dynamic testing is required after calibration: the paver travels 5m without load, and the detection system's correction response time for the simulated thickness deviation (±3mm) is ≤3 seconds. A similar process includes manually checking the paving thickness with a micrometer, but only as an emergency verification method. The calibration record must include the date, operator, calibration result and equipment number, and be archived for future reference. Through real-time monitoring and closed-loop control of ultrasonic thickness sensors, the paving thickness deviation can be stably controlled within ±2mm, reducing the lag and subjective errors of manual detection. The joint adjustment mechanism of the hydraulic servo mechanism and the vibrating rammer can dynamically compensate for the thickness fluctuation caused by uneven base and improve the uniformity of the paving layer. The calibration process ensures the long-term stability of the measurement system, provides the basic conditions for consistent thickness in the subsequent rolling process, and reduces the risk of local insufficient compaction caused by thickness deviation.

[0031] In another embodiment of the present invention, during the initial compaction stage, an atomized water spraying system is arranged above the steel wheel of the double steel wheel roller along its length, and the atomized water spraying system uses a compressed air pressure of 0.25-0.35MPa for atomization, and the spraying flow rate is controlled at 0.8-1.2L / min. The particle size of the atomized water droplets is 50-150μm, and the spraying angle is 45-60° relative to the tangent direction of the steel wheel; the rolling speed gradient of the double steel wheel roller is controlled within the range of 1.5-2.5m / min, and the overlapping width of adjacent rolling belts is 1 / 3-1 / 2 of the width of the steel wheel; the surface roughness Ra value of the steel wheel is maintained within the range of 6.3-12.5μm, and the surface porosity of the mixture is controlled between 7.5%-8.5% after the initial compaction is completed.

[0032] In the above embodiment, the compressed air pressure can be selected as 0.25MPa, 0.30MPa or 0.35MPa, and the spray flow rate can be adjusted to 0.8L / min, 1.0L / min or 1.2L / min. The particle size of the atomized water droplets is controlled to 50-150μm, and the spray angle can be set to 45°, 50° or 60° (relative to the tangent direction of the steel wheel). The equipment can use the Lechler 136.304 fan nozzle, and its atomization uniformity error is ≤±5%. The nozzle can be installed on a transverse bracket 30-50cm above the steel wheel of a double steel wheel roller, and the bracket spacing matches the width of the steel wheel. A similar process includes using a centrifugal atomizing disk instead of a nozzle, but a speed monitoring device needs to be added to avoid atomization failure. The water source can be a deionized water storage tank connected to the roller's own water pump system, and the water pump flow accuracy is controlled to ±0.05L / min. In the above embodiment, the rolling speed of the double steel wheel roller can be set to 1.5m / min, 2.0m / min or 2.5m / min, and the overlapping width of adjacent rolling belts is 1 / 3 of the steel wheel width (such as 710mm overlap when the steel wheel width is 2130mm) or 1 / 2 (1065mm). The surface roughness Ra value of the steel wheel can be maintained at 6.3μm, 9.4μm or 12.5μm by sandblasting, and the sandblasting material can be steel shot with a particle size of 0.3-0.6mm. A similar process includes using laser engraving to increase the texture of the steel wheel, but the texture depth needs to be tested regularly. After the rolling is completed, the vacuum sealing method can be used to detect the surface porosity of the mixture. The sampling positions are arranged every 5m in the longitudinal direction and 3 points in the transverse direction, and the porosity threshold is set to 7.5%-8.5%. In the above embodiment, the atomized water system needs to clean the filter every 4 hours, the filter aperture is ≤100μm, and the blockage alarm pressure is set to 0.4MPa. The steel wheel temperature monitoring can use a PT100 temperature sensor, which is installed at the axial center position inside the steel wheel to transmit data to the cab display in real time. When the steel wheel temperature is greater than 53°C, the built-in spiral water channel cooling system is automatically started, and the water flow rate is controlled to 5-8L / min. A similar process includes the use of external spray cooling, but the water volume needs to be controlled to avoid a sudden drop in the surface temperature of the mixture. After the operation is completed, the water tank needs to be emptied to prevent the pipes from freezing and cracking in low temperature environments. The drain valve can be installed at the lowest point at the bottom of the tank. Through the coordinated control of atomized water parameters and steel wheel roughness, a uniform water film can be formed in the initial compaction stage, effectively preventing the mixture from adhering to the steel wheel and causing damage to the surface texture. The limitation of rolling speed and overlapping width ensures uniform distribution of compaction energy and avoids local under- or over-pressure. The threshold setting of surface porosity of 7.5%-8.5% provides reasonable space for aggregate reconstruction in the re-compaction stage and reduces the risk of aggregate crushing. The real-time monitoring and maintenance mechanism ensures the long-term stable operation of the system and adapts to the needs of high-frequency construction conditions.

[0033] In another embodiment of the present invention, the double steel wheel roller is equipped with a temperature field uniformity control system, which includes an array of infrared temperature measurement modules symmetrically distributed along the steel wheel axis, each temperature measurement module includes multiple detection units, and the spacing between adjacent detection units is 15-20 cm. Each temperature measurement module collects the surface temperature data of the mixture within each 0.5 m × 0.5 m grid in the width direction in real time; the temperature field uniformity control system has a built-in temperature difference gradient calculator. When the temperature difference gradient of three consecutive grid units along the rolling direction exceeds 2°C / m, the servo controller of the travel motor of the double steel wheel roller is triggered, and the temperature is adjusted according to ΔV=0.1×(ΔT-15) The rolling speed of the double steel wheel roller is dynamically adjusted by 100m / min, where ΔT is the maximum temperature difference measured in three consecutive grid units. The spiral water channel cooling system inside the steel wheel is simultaneously activated during the adjustment process to maintain the working temperature of the steel wheel within the range of 50±3℃. The temperature field uniformity control system is also equipped with a temperature control compensation module. When the ambient temperature is greater than 35℃, the initial rolling speed reference value is automatically reduced by 0.2-0.5m / min and the atomized water spray flow rate is increased by 15%-20%.

[0034] In the above embodiment, the array infrared temperature measurement module can use a FLIR A615 thermal imager, each module contains 8 detection units, and the spacing between adjacent units can be set to 15cm, 17cm or 20cm. The module can be installed in the axially symmetrical position of the steel wheel of the double-wheel roller, 30-50cm away from the surface of the steel wheel, and fixed to the roller frame through a universal bracket. Data acquisition is divided into 0.5m×0.5m grids, and the temperature data in each grid is updated twice per second. A similar process includes the use of a thermocouple array instead of infrared temperature measurement, but the sensor needs to be embedded in the mixture. The thermal imager is powered by a 24V vehicle power supply, and the data is transmitted to the control terminal via the CAN bus. In the above embodiment, the temperature difference gradient threshold is set to 2°C / m. When the temperature difference gradient of three consecutive grid units exceeds this value, the walking motor servo controller can adjust the rolling speed according to the formula ΔV=0.1×(ΔT-15). The speed adjustment step can be set to 0.1m / min, 0.2m / min or 0.3m / min, where ΔT is the measured maximum temperature difference value (for example, when ΔT=20°C, ΔV=0.5m / min). The servo controller can use Siemens S7-1200 series PLC, whose response time is ≤0.3 seconds. Similar processes include using fuzzy logic algorithms to optimize the adjustment amount, but a temperature difference-speed mapping relationship database needs to be established in advance. During the adjustment process, the working temperature of the steel wheel needs to be maintained at 47°C, 50°C or 53°C through the spiral water channel cooling system. In the above embodiments, when the ambient temperature > 35°C, the initial rolling speed reference value can be reduced by 0.2 m / min, 0.3 m / min or 0.5 m / min, and the atomized water spraying flow rate can be increased by 15%, 17% or 20%. For ambient temperature detection, a Testo 635-1 type temperature and humidity meter can be selected and installed at the ventilation location on the top of the roller cab. The water pump for the cooling system can be a Grundfos CRN1-7 type, with a flow rate adjustment range of 3 - 10 L / min and the water temperature controlled at 15 - 25°C. Similar processes include using a sunshade to reduce the radiant heat of the steel wheel, but it is necessary to ensure that the rolling operation space is not affected. The compensation parameters can be manually overridden through the human-machine interface, and in case of emergency, it can be switched to the preset safety mode. Through real-time monitoring of the grid temperature field and dynamic speed adjustment, the compaction differences caused by uneven surface temperature distribution of the mixture can be effectively suppressed. The temperature difference gradient feedback mechanism precisely matches the input of rolling energy and reduces the risk of aggregate crushing caused by local overpressure. The environmental temperature control compensation strategy enhances the adaptability of the system under high-temperature conditions and avoids the problems of mixture sticking to the steel wheel or cold shrinkage cracking caused by overheating of the steel wheel. Ultimately, the temperature uniformity control of the rolling area is achieved, improving the overall density and durability of the thin-layer structure.

[0035] In another embodiment of the present invention, during the recompaction stage, when using a 12-ton vibratory roller for rolling, the offset angle between the vibrating wheel and the traveling direction is maintained at 5° - 8°, and the overlapping width of adjacent rolling belts is 1 / 4 - 1 / 3 of the width of the vibrating wheel. During each pass of rolling, the phase angle of the vibrating wheel is switched at 60° intervals; during the recompaction stage, the electromagnetic field generator is started synchronously. The electromagnetic field generator is fixed to the frame of the vibratory roller through a mounting bracket and is located 0.3 - 0.5 meters in front of the vibrating wheel. A 50 - 100 Hz alternating magnetic field is applied in front of the vibrating wheel through the electromagnetic field generator, and the magnetic field intensity is 0.3 - 0.5 T, so that the flaky and needle-shaped aggregates in the mixture are oriented along the rolling direction.

[0036] In the above embodiments, the offset angle between the vibrating wheel and the traveling direction can be set at 5°, 6° or 8°, and the phase angle switching interval is 60°, 120° or 180°. A XCMG XS223JE type vibratory roller can be selected as the roller, with a vibrating wheel diameter of 1200 mm and a width of 2130 mm. The phase angle switching mechanism can be integrated at the end of the vibrating shaft, and the angle positioning is achieved by driving a gear set through a servo motor, with a positioning accuracy ≤ ±0.5°. Similar processes include using a hydraulic motor to drive the phase adjustment, but a pressure compensation valve needs to be added to maintain the angle stability. When assembling the vibrating wheel, the offset angle adjustment mechanism can be installed at the connection between the vibrating box and the frame, and an angle scale is equipped to assist manual fine-tuning. In the above embodiment, the electromagnetic field generator can use Nanyang explosion-proof GBB10-100 alternating magnetic field device, which is installed 0.3m, 0.4m or 0.5m in front of the vibrating wheel and fixed to the side of the roller frame through an L-shaped bracket. The magnetic field frequency can be adjusted to 50Hz, 75Hz or 100Hz, and the magnetic field strength is set to 0.3T, 0.4T or 0.5T. The coil winding can use copper core electromagnetic wire with a cross-sectional area of ​​4mm² and an outer layer wrapped with a high-temperature resistant silicone insulation layer. A similar process includes the use of a permanent magnet array to generate a static magnetic field, but regular demagnetization and maintenance are required. The power supply system can be connected to the roller battery, the voltage fluctuation is controlled within ±5%, and the overload protection threshold is set to 110% of the rated current. In the above embodiment, the overlapping width of adjacent rolling belts can be controlled to be 1 / 4 (533mm) or 1 / 3 (710mm) of the width of the vibrating wheel. After the operation, the arrangement direction of the aggregate can be detected by X-ray tomography. The sampling area takes one section every 10m in the longitudinal direction to detect the ratio of the angle between the long axis of the aggregate and the rolling direction ≤15°. A similar process includes visual inspection using an industrial endoscope, but it is necessary to cooperate with image analysis software to quantify the degree of orientation. The detection equipment can use a Nikon XT H 450 CT scanner with a resolution of ≤20μm. During verification, the sample size is 100mm×100mm×50mm, and it is taken from the middle of the rolling layer to avoid interference from edge effects. By switching between the offset angle and the phase angle, the vibration energy propagation path is optimized to reduce the unidirectional arrangement defects of aggregates caused by rolling in the same direction. The alternating magnetic field induces the needle-shaped aggregates to be oriented along the rolling direction, enhancing the interlocking effect of the mixture skeleton. The clear rolling belt overlap control and detection method ensures the uniform distribution of compaction energy and improves the road surface's anti-rutting ability and load transfer efficiency. The synergistic effect of the electromagnetic field parameters and the vibration process makes the void distribution more uniform after re-compaction, reducing the risk of local stress concentration.

[0037] In another embodiment of the present invention, in the final pressure stage, the dynamic control range of the internal pressure of the tire of the 16-ton tire roller is 0.5-0.8 MPa, the control step is ≤0.02 MPa, and the surface temperature of the mixture satisfies: P =0.7+0.015( T s -80), where P is the tire pressure in MPa, T s is the mixture surface temperature, T s ≥60℃, take the numerical value.

[0038] In the above embodiment, the tire pressure regulation system may select the intelligent air pressure control module equipped on the XCMG XP302 tire roller. This module realizes pressure regulation through an electric control air pump and a pressure sensor. The dynamic regulation range is set to four preset gears of 0.5 MPa, 0.6 MPa, 0.7 MPa, and 0.8 MPa, and fine-tuning is performed in the range of 0.55 - 0.75 MPa according to the working conditions during actual construction. The regulation step length can be set to three modes of 0.01 MPa, 0.015 MPa, or 0.02 MPa. The pressure sensor is installed on the tee joint at the tire valve core to monitor the pressure fluctuation in real time. The air pressure regulation actuator can select the SMC ITV2050 type electro-pneumatic proportional valve, whose response time ≤ 0.5 seconds and control accuracy is ±0.005 MPa.

[0039] In the above embodiment, for temperature detection, a Fluke 62 Max infrared thermometer can be selected and installed on the bracket 0.3 meters in front of the tire ground contact at the front of the roller. The measurement point is on the surface of the mixture 1.2 meters in front of the tire traveling direction. In the formula, the temperature value Ts takes the average value of three consecutive samples at the measurement point, and the sampling interval is 10 seconds. When the ambient temperature is lower than 5°C, the formula is corrected to P = 0.7 + 0.015(Ts - 80) + 0.02(5 - Ta), where Ta is the ambient temperature. The pressure calculation module can be integrated in the LC5-2D type controller in the cab of the roller, and the calculation result is transmitted to the air pressure regulation system through the CAN bus.

[0040] For assembly and implementation, the intelligent air pressure control module is installed in the equipment compartment near the rear axle of the roller and is connected to each tire air chamber through a high-pressure air pipe. The temperature sensor bracket adopts an adjustable angle design, and the installation height is 0.8 - 1.0 meters from the ground to ensure that the measurement spot diameter ≤ 50 mm. After the air pressure regulation command is generated, the system preferentially regulates the pressure of the front wheel group and then the pressure of the rear wheel group, and the pressure difference between the front and rear wheels is controlled within ±0.03 MPa. During the implementation process, the tire pressure is automatically checked once every 10 meters of rolling length. When the check deviation exceeds 0.01 MPa, an alarm is triggered and the operation is paused.

[0041] By dynamically regulating the tire pressure and establishing a functional relationship with the mixture temperature, the ground contact pressure in the final compaction stage is adapted to the viscoelastic change of the material, effectively eliminating the wheel track imprints. Precise step length control ensures a smooth transition of pressure adjustment and avoids surface texture damage caused by sudden pressure changes. The temperature compensation mechanism improves the pressure regulation accuracy in low-temperature environments and ensures the uniformity of the final compaction density. The systematic assembly scheme realizes the real-time linkage of pressure and temperature parameters, makes the compaction work distribution more reasonable, and effectively stabilizes the mixture skeleton structure.

[0042] In another embodiment of the present invention, during the longitudinal joint treatment, when paving the new mixture, the temperature of the mixture within 10 cm on the joint side is controlled to be 155 - 160 °C, and the surface of the reserved uncompacted mixture is preheated to 110 - 120 °C, with the temperature difference between the two ≤ 40 °C; during cross - joint rolling, the tandem roller operates in two stages. In the first stage, it statically compresses at a 45° oblique angle for 2 passes, with a rolling speed of 1.5 - 2.0 m / min. In the second stage, it switches to vibratory rolling at a 30° oblique angle for 1 pass, with a vibration frequency of 25 Hz and an amplitude of 0.4 mm; 0.6% - 0.8% of nano - montmorillonite modified asphalt is incorporated into the mixture within a depth of 3 cm on the surface of the reserved uncompacted mixture.

[0043] In the above - mentioned embodiment, for temperature control, a Fluke 568 infrared thermometer can be used for multi - point monitoring. The temperature detection points on the joint side are arranged at 5 cm, 10 cm, and 15 cm away from the joint line, and are longitudinally arranged at intervals of 2 meters for each point. For the preheating operation, a Wirtgen HE50 hot - air heating machine can be selected, with the width of the heating plate adjusted to 12 cm and moving parallel to the joint at a distance of 10 cm. The temperature - difference threshold can be set at three levels: 35 °C, 40 °C, and 45 °C. During actual construction, when the detected temperature difference reaches 38 °C, auxiliary heating is started, and when the temperature difference exceeds 42 °C, construction is suspended. For temperature data acquisition, an Advantech ADAM - 4017 thermocouple module can be selected and installed on the detection bracket on the joint side of the paver, with the height of the bracket from the ground being 0.7 meters.

[0044] In the above - mentioned embodiment, for the first - stage static compaction, a Dynapac CC624 tandem roller can be selected, with a steel - wheel width of 2130 mm and a working mass of 12.8 tons. For angle positioning, a Prometheus PM - A300 angle sensor can be installed on the steering mechanism of the roller to display the rolling angle in real time. During the second - stage vibratory rolling, the vibration system of a Hamm HD128 roller can be enabled, with the adjustable range of the vibration frequency being 25 - 35 Hz and the amplitude adjustment accuracy being 0.1 mm. For rolling - speed control, a Bonfiglioli GPG gearbox can be combined with a Danfoss MCO305 frequency converter, with the speed - adjustment step being 0.1 m / min. The overlapping width of adjacent rolling bands can be set in three modes: 30%, 35%, and 40% of the steel - wheel width.

[0045] In the above embodiments, the nano-montmorillonite modified asphalt can be selected from Jiangsu Xianke NMT-3 type modifier, and the dosage can be implemented in three gradients of 0.65%, 0.7%, and 0.75%. The addition of the modifier can use the Nanfang Road Machinery GLB-3000 type asphalt modification equipment, and it is mixed with the matrix asphalt at a temperature of 160-170 °C through a twin-screw extruder. The secondary feeding device of the XCMG XP303 paver can be selected for the surface treatment of the reserved mixture, and the depth adjustment accuracy of the feeding scraper is ±2 mm. During the addition operation, the modified asphalt spraying pipe can be installed at the middle position of the paver, 1.2 meters from the front edge of the feeding bottom plate, and the spraying pressure is maintained at 0.3-0.5 MPa.

[0046] The fusion of the new and old mixture interfaces is achieved through precise temperature gradient control, and the two-stage variable parameter rolling strategy balances the requirements of density and interface protection. The nano-modified material improves the thermal stability of the reserved mixture and prevents the destruction of the aggregate structure during rolling. The combined use of the angle sensor and the speed control system ensures the accuracy of the rolling track and reduces the risk of step difference at the joint. The temperature-rolling parameter linkage mechanism effectively controls the distribution of interface shear stress and guarantees the structural integrity of the joint area. The synergistic effect of the material modification process and construction parameters enhances the interlayer bonding strength and extends the service life of the road surface.

[0047] In another embodiment of the present invention, in the transverse joint treatment, the cutting depth is 5-8 mm below the lower bound of the loose layer, and the Ra value of the cutting surface roughness is controlled to be 3.2-6.3 μm; the emulsified asphalt applied is mixed with 0.3%-0.5% carbon nanotube toughening agent, and the coating amount is calculated according to the formula: Q =0.4 + 0.02 ( T a -20), where, Q is the coating amount, with the unit of kg / m 2 , T a is the ambient temperature, with the unit of °C, and the numerical value is taken.

[0048] In the above embodiments, during cutting, a Wirtgen SW16 type cutting machine equipped with tungsten carbide blades can be used, and the blade thickness is 12 mm. The cutting depth can be set in three gears of 5 mm, 6 mm, and 7 mm, and 1-3 mm is automatically compensated according to the thickness of the loose layer during actual construction. The roughness control can be achieved by adjusting the sawtooth angle of the blade, and the angle can be set in three modes of 30°, 45°, and 60°. The cutting speed can be set in three gears of 1.0 m / min, 1.5 m / min, and 2.0 m / min. The guide rail of the cutting machine can be installed with a Leica TS16 total station for path calibration. The blade is assembled on the front tool holder of the cutting machine, and the height adjustment range from the ground is 50-150 mm. The loose layer detection can use the Concreye LTD-2100 ground penetrating radar, and the antenna is installed on the bracket 0.5 meters behind the cutting machine.

[0049] In the above embodiments, the carbon nanotube toughening agent can be the multi-walled carbon nanotubes of Jiangsu Xianke CNT-200 type, with a tube diameter of 20 - 30 nm and a length of 10 - 20 μm. The blending operation can use the GLB-500 type modified asphalt mixing equipment of Nanfang Road Machinery, and be dispersed and processed at a speed of 3000 rpm for 30 minutes by a high-speed shearing machine. The emulsified asphalt can be the Shell CSS-1h type cationic emulsified asphalt, and the addition amount of the modifier can be implemented in three gradients of 0.35%, 0.4%, and 0.45%. The temperature of the mixing tank is controlled within the range of 55 - 65 °C, and the linear velocity of the mixing paddle is maintained at 8 - 10 m / s. The modified emulsified asphalt storage tank can be equipped with a double-screw stirrer, and the rotation speed is set at 15 - 20 rpm to prevent the settlement of carbon nanotubes.

[0050] In the above embodiments, for the environmental temperature detection, a Testo 635-1 type temperature and humidity meter can be selected and installed on the bracket 1.2 meters behind the cutting surface, and the measurement height is 1.5 meters from the ground. The coating equipment can be the GSA-12 type asphalt spraying truck of Greno, and the nozzle type can be the Spraymation 3050 fan-shaped nozzle, and the spraying pressure adjustment range is 0.2 - 0.6 MPa. The formula calculation can be integrated in the Siemens S7-1200 PLC of the spraying truck control system. When the environmental temperature is lower than 0 °C, the formula is automatically corrected to Q = 0.4 + 0.02(Ta - 20) + 0.05×|Ta / 10|. The spraying pipe can be installed on the adjustable bracket 0.8 meters behind the cutting machine, and the vertical distance between the nozzle and the cutting surface is maintained at 200 - 300 mm. For the verification of the coating amount, a Mettler-Toledo MS304TS weighing sensor can be selected, and samples are taken and detected every 20 meters in length, and the allowable deviation is ±0.05 kg / m².

[0051] The weakening layer is completely removed through precise cutting depth control, and the reasonable roughness interface enhances the penetration and anchoring effect of the emulsified asphalt. The modification of carbon nanotubes improves the flexibility and crack resistance of the asphalt film, and the temperature-adaptive coating formula ensures the stability of the bonding strength under different climate conditions. The automated cutting and spraying systems cooperate to standardize the joint treatment and reduce the parameter fluctuations caused by manual operation. The synergistic effect of the modified materials and process parameters effectively inhibits the joint cracking caused by temperature stress and extends the service life of the transverse joints. The systematic quality inspection mechanism ensures the uniformity of the interface treatment and improves the overall flatness of the road surface and the driving comfort.

[0052] The equipment quantity and processing scale described here are used to simplify the description of the present invention. The application, modification, and variation of the construction method of the thin-layer asphalt concrete of the present invention are obvious to those skilled in the art.

[0053] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A construction method for thin-layer asphalt concrete, characterized in that, Including: Step 1: Pretreat the surface of the base course, and then evenly spray an emulsified asphalt bonding layer on the surface of the base course. The spraying amount of the emulsified asphalt is 0.3 - 0.4 kg / m². After spraying, let it stand for 30 - 40 minutes to form a continuous bonding film; Step 2: Use a paver to pave the thin-layer asphalt concrete mixture. During paving, control the paving temperature of the mixture not to be lower than 155 °C, the walking speed of the paver is 2.5 - 3.5 m / min, and the paving thickness deviation does not exceed ±2 mm; Step 3: Use a combined compaction process to compact the paved layer. In the initial compaction stage, use a 10-ton double-drum roller to roll along the paving direction in a static pressure mode for 2 passes. During rolling, spray atomized water on the surface of the steel wheel to prevent the mixture from sticking to the wheel. When the initial compaction ends, the surface temperature of the mixture is not lower than 135 °C. In the recompaction stage, use a 12-ton vibrating roller to roll in a high-frequency and low-amplitude mode for 3 passes. The vibration frequency is set to 40 Hz and the amplitude is set to 0.8 mm. In the final compaction stage, use a 16-ton tire roller to roll at a speed of 6 km / h for 2 passes. After the final compaction, detect the compaction degree and control the compaction degree to reach more than 97% of the maximum theoretical density; Step 4: Reserve an uncompacted mixture width of 15 cm at the longitudinal joint. During subsequent paving, use a hot joint method to overlap the newly paved mixture with the reserved uncompacted mixture by 5 cm. The overlapping area is rolled across the joint at an angle of 45 degrees with a double-drum roller. At the transverse joint, use a cutting machine to vertically cut off the loose mixture at the end. After the cutting surface is coated with emulsified asphalt, then pave the new mixture. When paving the new mixture, it extends 20 cm beyond the cutting line and is trimmed to be flush by hand.

2. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, Pretreat the surface of the base course, including: use a high-pressure water gun to remove the floating dust and loose particles on the surface of the base course, use a hot air device to dry the surface of the base course until the moisture content is less than 3%, use a 3-meter straightedge to detect the flatness of the surface of the base course and mark the sunken areas. The areas where the sunken depth exceeds 3 mm are filled with hot asphalt mixture to be flush with the surrounding area. After filling, use a double-drum roller to roll at a walking speed of 2 km / h for 3 passes.

3. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, During paving, control the paving temperature of the mixture not to be lower than 155 °C, including: after the mixture arrives at the construction site, use an infrared thermometer to detect the temperature at three points, namely the front, middle, and rear of each truckload of the mixture before unloading. The front point is at the top of the material pile 0.8 - 1 m away from the tail of the carriage, the middle point is in the middle of the material pile at half of the carriage length, and the rear point is at the bottom of the material pile 0.6 - 0.8 m away from the front of the carriage; when the detected temperature at any one point is lower than 160 °C, start the emergency paving procedure, increase the walking speed of the paver to the upper limit value of 3.5 m / min, and start the heating system of the paver to raise the temperature of the screed to 120 - 130 °C. At the same time, increase the vibration rammer frequency from 25 Hz to 30 Hz; when the detected temperature at any one point is lower than 155 °C, it is determined as unqualified mixture and is discarded.

4. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, An ultrasonic thickness sensor is installed under the screed plate of the paver. The ultrasonic thickness sensor collects paving thickness data every 1 meter and compares it with the preset thickness data. When the deviation exceeds ±2 mm, the hydraulic servo mechanism is controlled by the paver control system to adjust the screed plate inclination angle at an angular velocity of 0.05° / s. At the same time, the impact force of the vibrating rammer is adjusted to 105%-120% of the set value.

5. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, During the initial compaction stage, an atomized water spray system is set above the steel wheel of the double steel wheel roller along its length. The atomized water spray system uses a compressed air pressure of 0.25-0.35MPa for atomization, the spraying flow rate is controlled at 0.8-1.2L / min, the particle size of the atomized water droplets is 50-150μm, and the spraying angle is 45-60° relative to the tangent direction of the steel wheel; the rolling speed gradient of the double steel wheel roller is controlled within the range of 1.5-2.5m / min, and the overlapping width of adjacent rolling belts is 1 / 3-1 / 2 of the steel wheel width; the surface roughness Ra value of the steel wheel is maintained in the range of 6.3-12.5μm, and the surface porosity of the mixture is controlled between 7.5%-8.5% after the initial compaction is completed.

6. The construction method of thin-layer asphalt concrete according to claim 5, characterized in that, The double-wheel roller is equipped with a temperature field uniformity control system, which includes an array of infrared temperature measurement modules symmetrically distributed along the axis of the steel wheel. Each temperature measurement module contains multiple detection units, and the spacing between adjacent detection units is 15-20 cm. Each temperature measurement module collects real-time surface temperature data of the mixture in a grid of 0.5 m × 0.5 m in the width direction (perpendicular to the rolling direction); the temperature field uniformity control system has a built-in temperature gradient calculator. When the temperature gradient of three consecutive grid units along the rolling direction exceeds 2°C / m, the servo controller of the double-wheel roller travel motor is triggered, and the temperature is calculated according to ΔV=0.1×(ΔT-15). The rolling speed of the double steel wheel roller is dynamically adjusted by 100m / min, where ΔT is the maximum temperature difference measured in three consecutive grid units. The spiral water channel cooling system inside the steel wheel is simultaneously activated during the adjustment process to maintain the working temperature of the steel wheel within the range of 50±3℃. The temperature field uniformity control system is also equipped with a temperature control compensation module. When the ambient temperature is greater than 35℃, the initial rolling speed reference value is automatically reduced by 0.2-0.5m / min and the atomized water spray flow rate is increased by 15%-20%.

7. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, During the re-compacting stage, a 12-ton vibratory roller is used, and the vibratory wheel maintains an offset angle of 5°-8° with the travel direction during the rolling process. The overlapping width of adjacent rolling belts is 1 / 4-1 / 3 of the width of the vibratory wheel, and the phase angle of the vibratory wheel is switched at 60° intervals during each rolling. During the re-compacting stage, the electromagnetic field generator is started synchronously. The electromagnetic field generator is fixed to the frame of the vibratory roller through a mounting bracket and is located 0.3-0.5 meters in front of the vibratory wheel. The electromagnetic field generator applies a 50-100Hz alternating magnetic field in front of the vibratory wheel with a magnetic field strength of 0.3-0.5T, so that the needle-like flake aggregate in the mixture is oriented along the rolling direction.

8. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, During the final compaction stage, the dynamic regulation range of the inner pressure of the tires of the 16-ton pneumatic roller is 0.5 - 0.8 MPa, the regulation step size ≤ 0.02 MPa, and it satisfies the following with the surface temperature of the mixture: P = 0.7 + 0.015( T s - 80), where P is the tire pressure, in MPa T s is the surface temperature of the mixture T s ≥ 60 °C, take the value 9. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that During the longitudinal joint treatment, when paving the new mixture, control the temperature of the mixture within 10 cm of the joint side to be 155 - 160 °C, and preheat the surface of the reserved uncompacted mixture to 110 - 120 °C, with the temperature difference between the two ≤ 40 °C; during the cross-seam rolling, the double-drum roller operates in two stages. In the first stage, statically roll 2 times at a 45° oblique angle, with a rolling speed of 1.5 - 2.0 m / min. In the second stage, switch to vibratory rolling 1 time at a 30° oblique angle, with a vibration frequency of 25 Hz and an amplitude of 0.4 mm; incorporate 0.6% - 0.8% of nano-montmorillonite modified asphalt into the mixture within a depth of 3 cm from the surface of the reserved uncompacted mixture.

10. The construction method of thin-layer asphalt concrete according to claim 1, characterized in that, In the treatment of transverse joints, the cutting depth reaches 5 - 8 mm below the lower boundary of the loose layer, and the Ra value of the cutting surface roughness is controlled to be 3.2 - 6.3 μm; the emulsified asphalt applied is mixed with 0.3% - 0.5% carbon nanotube toughening agent, and the coating amount is calculated according to the formula: Q = 0.4 + 0.02( T a - 20), where, Q is the coating amount, with the unit of kg / m 2 , T a is the ambient temperature, with the unit of °C, taking the numerical value.