A multi-factor coupling aging test device and method for asphalt pavement

Abstract

This invention belongs to the technical field of highway engineering material performance testing, and relates to a multi-factor coupled aging test device and method for asphalt pavement. The test device includes a test chamber with an internal test compartment. Inside the test chamber are a simulated traffic load system, a sample holding platform, a water spray circulation system, an ultraviolet lamp assembly, and a heating and airflow circulation system. The simulated traffic load system includes a horizontal reciprocating motion mechanism, a vertical loading mechanism, and a loading roller, which can apply dynamic reciprocating compaction loads to asphalt mixture specimens. Combined with the water spray circulation system to generate dynamic water pressure, it simultaneously reproduces the multi-factor coupled environment of humidity and heat, ultraviolet radiation, traffic load, and load-induced dynamic water pressure. This invention also provides a test method based on this test device, which can conduct aging tests in stages using regional meteorological data. Compared with existing technologies, this invention can more comprehensively reproduce the service environment of asphalt pavement, improving the engineering reference value of the test results.

Description

Technical Field

[0001] This invention belongs to the field of highway engineering material performance testing technology, specifically relating to a multi-factor coupled aging test device and method for asphalt pavement. Background Technology

[0002] Asphalt pavements are subjected to a variety of complex natural environments and traffic loads during their long service life. They not only face the challenges of ultraviolet radiation, drastic temperature and humidity changes, and rainwater erosion, but also the repeated traffic loads and the scouring effect of water pressure generated by vehicle wheels pressing against surface water. The combined effect of these environmental and mechanical factors significantly accelerates the aging process of asphalt mixtures, exacerbating spalling and material performance degradation, leading to pavement defects such as rutting, cracking, and loosening, and drastically shortening the actual service life of roads. To scientifically evaluate the long-term durability of asphalt mixtures and guide the optimal design of pavement materials, researchers typically employ accelerated aging tests in the laboratory to rapidly reproduce the multi-factor coupled aging process experienced by real pavements within a short period, thereby clarifying the damage evolution laws of the materials.

[0003] Chinese patent CN222774576U discloses a multi-factor coupled testing device for asphalt mixtures involving water, temperature, and force. The device mainly consists of a pressure tank, tank cover, pressure gauge, air pump, heating belt, motor, transmission pressure plate, spring column, and inlet / outlet water pipes. The external heating belt heats the pressure tank to simulate a high-temperature environment. Water is injected into the tank to immerse the specimen in static water. Simultaneously, the motor drives a threaded shaft and the transmission pressure plate downwards to apply a static mechanical load, while the air pump system applies pressure to the sealed pressure tank. This testing device can achieve the coupled effects of high temperature, static water immersion, and static pressure within a sealed space, facilitating the penetration of water into the asphalt mixture and thus accelerating specimen damage testing.

[0004] However, the aforementioned test setup cannot fully replicate the actual service environment of asphalt pavement and still has certain limitations in practical applications. Firstly, while the setup couples the effects of moisture, temperature, and static pressure, it does not consider the influence of ultraviolet (UV) radiation on asphalt mixtures. In actual service, UV radiation is a key factor inducing photo-oxidative aging of asphalt, especially in areas with strong sunlight, where UV aging significantly degrades the performance of asphalt mixtures. The absence of this factor leads to a significant deviation between the test environment and actual pavement service conditions, making it difficult to fully reflect the actual aging process of asphalt mixtures. Secondly, the setup employs a static water immersion combined with a single vertical static load. The load is fixed and lacks reciprocating motion, failing to simulate the dynamic compaction process of real traffic loads or the scouring effect of hydrodynamic pressure generated by traffic loads squeezing surface water and internal pore water. This makes it difficult to replicate the true mechanism of water damage in asphalt pavements, limiting the reference value of the test results for practical engineering. Summary of the Invention

[0005] The purpose of this invention is to propose a multi-factor coupled aging test device for asphalt pavement to solve the technical problem that existing test devices are unable to fully reproduce the real aging process of asphalt pavement; the purpose of this invention is also to provide a multi-factor coupled aging test method for asphalt pavement to more comprehensively reproduce the multi-field coupled service environment of asphalt pavement.

[0006] To solve the above problems, the technical solution of the multi-factor coupled aging test device for asphalt pavement proposed in this invention is as follows:

[0007] A multi-factor coupled aging test device for asphalt pavement includes: The test chamber contains a test compartment. The simulated vehicle load system is set inside the test chamber and includes a horizontal reciprocating motion mechanism, a vertical loading mechanism, and a loading roller. The vertical loading mechanism is connected to the output end of the horizontal reciprocating motion mechanism, and the loading roller is connected to the output end of the vertical loading mechanism and located inside the test chamber. It is used to press down on and contact the asphalt mixture specimen to apply a dynamic reciprocating rolling load to it. The sample holding platform, located at the bottom of the test chamber, is used to support asphalt mixture specimens; The water spraying circulation system is installed inside the test chamber and above the sample holding platform. It is used to spray water mist onto the surface of the asphalt mixture specimen and regulate the humidity of the test chamber. It works in conjunction with the reciprocating rolling action of the loading roller to squeeze out the accumulated water and generate dynamic water pressure. An ultraviolet lamp assembly, located at the top of the test chamber and above the sample holding platform, is used to provide an adjustable intensity ultraviolet radiation environment to the asphalt mixture specimens. A heating and airflow circulation system is installed inside the test chamber to provide a stable and uniform high-temperature environment for aging tests.

[0008] Beneficial effects of the test device: This invention adopts a loading method that combines horizontal reciprocating motion with vertical loading. Combined with water spraying, it can create a dynamic water flow scouring effect inside the specimen, reproducing the actual process of water damage to the road surface. At the same time, in conjunction with the water spraying circulation system, ultraviolet lamp group and heating and airflow circulation system, it can construct a coupled aging environment in the same test chamber that can simultaneously reproduce multiple factors such as temperature, humidity, ultraviolet radiation, traffic load and load-induced water pressure. This makes up for the incomplete coverage of factors in existing test devices, making the test environment closer to the actual service environment of asphalt pavement, thereby improving the engineering reference value of the test results.

[0009] Furthermore, the horizontal reciprocating motion mechanism is a lead screw and nut transmission mechanism, including a first servo motor, a drive lead screw that is driven by the first servo motor, and a nut seat that is threaded onto the drive lead screw. The vertical loading mechanism is connected to the nut seat.

[0010] Beneficial effects: The horizontal reciprocating motion mechanism adopts a lead screw and nut transmission form, powered by a servo motor. The power transmission is smooth and the transmission accuracy is high, which can ensure the consistency of the rolling action; the nut seat can drive the vertical loading mechanism to move synchronously, ensuring the coordination between horizontal motion and vertical loading.

[0011] Furthermore, the vertical loading mechanism includes a second servo motor, a reversing gear set, and an electric cylinder. The output shaft of the second servo motor is connected to the horizontal input end of the reversing gear set, and the vertical output end of the reversing gear set is connected to the input end of the electric cylinder. A vertical connecting rod is connected between the housing of the reversing gear set and the nut seat. The loading pressure roller is rotatably mounted on the output rod of the electric cylinder. The second servo motor is connected to the housing of the reversing gear set through multiple guide shafts.

[0012] Beneficial effects: The reversing gear set can change the direction of power output, adapting to the spatial layout requirements of vertical loading; the force output by the electric cylinder is stable and controllable, and can adjust the contact pressure of the loading roller on the specimen to meet the test requirements of different load levels. The loading roller adopts a rotating assembly form, which can simulate the driving conditions and roll smoothly on the surface of the specimen, while reducing additional damage to the surface of the specimen.

[0013] Furthermore, the test chamber is provided with a base and a support column connected to the base. The test chamber is located above the base, and the support column passes through the test chamber. The support column is connected with guide rails that are parallel to the drive screw and arranged at intervals in the vertical direction. The vertical connecting rod is provided with a slider that slides with the guide rails. The guide shaft slides with the support column in the horizontal direction.

[0014] Beneficial effects: The support columns and guide rails can withstand the overall weight of the vertical loading mechanism, while constraining the direction of movement, preventing deviation and swaying during operation, and improving the operational accuracy and structural reliability of the loading action.

[0015] Furthermore, the sample holding platform includes a sample carrier, a tray, and a support platform. The sample carrier, tray, and support platform are all porous structures and each has a through flow channel hole. The sample carrier is used to place the asphalt mixture specimen. The sample carrier is fixed on the tray, and the tray is rotatably mounted on the support platform. The test chamber is also equipped with a rotary drive mechanism for driving the tray to rotate. A water collection tank communicating with the flow channel hole is provided below the support platform, and a screen is also provided above the water collection tank. The screen covers at least each flow channel hole on the support platform.

[0016] Beneficial effects: It allows the specimen to receive UV irradiation and spraying evenly around its circumference, avoiding the impact of uneven local effects on the test results; the sample stage, tray, and support platform are all equipped with a porous flow channel structure, which facilitates the rapid downward discharge of water and reduces surface water retention. Together with the water collection tank below, it can collect water and provide a basis for circulating water supply; the screen can block aggregate particles and other debris that fall off the specimen, preventing particles from entering the water collection tank and clogging the circulating water path, ensuring the continuous and stable operation of the spray water circulation system.

[0017] Furthermore, the heating and airflow circulation system includes a heat exchange chamber surrounded by a flow equalization plate and a baffle, a heating element located inside the heat exchange chamber and fixed on the baffle, and a fan, a return air duct, and an inlet air duct located outside the heat exchange chamber. The return air duct is connected to the inlet air duct, the inlet end of the fan is connected to the return air duct, and the outlet end of the fan is connected to the heat exchange chamber. The heat exchange chamber is arranged on the side wall of the test chamber, and the sample holding platform is located between the inlet air duct and the heat exchange chamber. The inlet air duct is provided with multiple air inlets facing the flow equalization plate.

[0018] Beneficial effects: Uniform heating of the specimen can be achieved through airflow circulation, ensuring that the specimen is heated evenly as a whole, avoiding local temperature differences that are prone to occur in existing external wall heating methods, thereby improving the accuracy of test results.

[0019] Furthermore, the water spray circulation system includes a water pump, a water pipe, and a high-pressure micro-mist humidifier and a high-pressure nozzle installed on the water pipe; the water outlet of the water pump is connected to the water pipe, the water inlet of the water pump is connected to the water collection tank, and a water supply valve is also connected to the water pipe.

[0020] Beneficial effects: The high-pressure micro-mist humidifier can regulate the air humidity in the test chamber, and the high-pressure nozzle can directly supply water to the surface of the specimen. The two work together to meet the environmental humidity control requirements and provide sufficient water source for water flow rinsing; the water pump draws water from the water collection tank and delivers it to the pipeline to realize the recycling of test water and reduce water consumption; the pipeline is equipped with a water replenishment valve to facilitate timely replenishment of water loss during the test and maintain the normal operation of the water system.

[0021] Furthermore, the test chamber is divided into upper and lower parts. The upper part is the transmission area that houses the transmission components of the simulated vehicle load system, and the lower part is the test chamber. A door is provided on the test chamber corresponding to the position of the test chamber. A flexible diaphragm is provided on the inside of the door to prevent the leakage of high temperature and humid airflow.

[0022] Beneficial effects: Separating the transmission components from the test chamber can prevent the high temperature, high humidity and ultraviolet radiation environment from corroding the precision transmission components and extend the service life of the test device; the flexible diaphragm installed on the inside of the door can block the leakage of hot and humid air from the chamber when the door is opened, reduce the fluctuation of environmental parameters in the test chamber, and protect the operators from the effects of high temperature airflow, thus improving the safety of the operation process.

[0023] Furthermore, it also includes a sensor module and a pressure balancing valve; the sensor module includes a temperature sensor, a humidity sensor and an ultraviolet radiometer installed in the test chamber, used to monitor the environmental parameters in the test chamber in real time; the pressure balancing valve is used to monitor the real-time air pressure inside the test chamber and automatically release air to maintain the stability of the internal air pressure when the air pressure is too high.

[0024] Beneficial effects: The sensor module can collect real-time data on temperature, humidity and ultraviolet radiation intensity inside the chamber, providing data support for the control of test conditions and ensuring that various test parameters remain stable within the set range; the air pressure balance valve can monitor the air pressure status inside the test chamber and automatically vent when the air pressure is too high, avoiding safety hazards caused by excessive internal air pressure and maintaining the stability of the air pressure status inside the test chamber.

[0025] The technical solution of the multi-factor coupled aging test method for asphalt pavement proposed in this invention is as follows: A multi-factor coupled aging test method for asphalt pavement, based on the multi-factor coupled aging test device for asphalt pavement described in any of the above technical solutions, includes the following steps: Step S1: Prepare shaped asphalt mixture specimens and blank control group specimens; Step S2: Obtain actual meteorological data of the test area, divide the annual meteorological data into multiple natural stages, and calculate the test parameters corresponding to each natural stage. The test parameters include indoor simulated ultraviolet light duration, test temperature, spray volume, ambient humidity, loading pressure and loading rate. Step S3: Fix the asphalt mixture specimen in the center of the sample holding platform, adjust the initial distance between the loading roller and the asphalt mixture specimen, and set the test parameters; Step S4: Start the test device. First, adjust the temperature and humidity in the test chamber to the preset value through the heating and air circulation system and the water spray circulation system. Then, start the ultraviolet lamp group and the simulated vehicle load system to make the loading roller reciprocate to roll the asphalt mixture specimen. At the same time, the water spray circulation system sprays water onto the surface of the asphalt mixture specimen to form a multi-factor coupled aging environment. Step S5: After the test, start the cooling program. After the temperature in the test chamber drops to room temperature, take out the asphalt mixture specimens and perform performance tests on the aged asphalt mixture specimens and the blank control group specimens to analyze the influence of multi-factor coupled aging on the performance of asphalt mixtures.

[0026] The beneficial effects of the test method are as follows: Based on the above-mentioned test device, the test method of the present invention can simulate the multi-field coupled aging environment of asphalt pavement in actual service, and fully restore the real aging process of asphalt pavement; by acquiring the actual meteorological data of the test area and dividing the whole year into multiple natural stages, the corresponding indoor test parameters of each stage are calculated, so that the conditions of the indoor accelerated aging test can reflect the differences in climate characteristics of different seasons, and improve the matching between the test results and the test area; the setting of blank control group specimens provides a benchmark reference for subsequent performance comparison analysis, so that the influence law of multi-factor coupled aging on the performance of asphalt mixture can be accurately identified, thereby providing a reliable basis for the optimization design of pavement materials. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the internal structure of a multi-factor coupled aging test device for asphalt pavement. Figure 2 This is a front view of the multi-factor coupled aging test device for asphalt pavement. Figure 3 To display a structural schematic diagram of the simulated traffic load system; Figure 4 This is a front view of the water spray circulation system; Figure 5 A top view of the water spray circulation system; Figure 6 This is a schematic diagram of the ultraviolet lamp assembly. Figure 7 This is a schematic diagram of the heating and airflow circulation system; Figure 8 This is a schematic diagram of the sample holding platform.

[0028] Explanation of reference numerals in the attached figures: 1. Test chamber; 11. Chamber door; 12. Observation window; 13. Display screen; 14. Operation buttons; 2. Support column; 3. Simulated trolley load system; 31. Horizontal reciprocating motion mechanism; 311. First servo motor; 312. Drive screw; 313. Nut seat; 32. Vertical loading mechanism; 321. Second servo motor; 322. Transmission shaft; 323. Reversing gear set; 324. Guide shaft; 325. Connecting plate; 326. Electric cylinder; 327. Vertical connecting rod; 328. Slider; 33. Loading roller; 34. Guide rail; 4. Water spray circulation system; 41. 42. Water pipe; 43. Water distribution connector; 44. High-pressure micro-mist humidifier; 45. High-pressure nozzle; 46. Water collection tank; 47. Water supply valve; 5. Ultraviolet lamp; 6. Heating and airflow circulation system; 61. Fan; 62. Flow equalization plate; 63. Baffle; 64. Heating rod; 65. Air inlet; 66. Return air duct; 67. Air inlet duct; 7. Sample holding platform; 71. Sample carrying platform; 72. Tray; 73. Support platform; 74. Rotating shaft; 75. Flow channel hole; 76. Third servo motor; 77. Transmission gear set; 8. Base; 9. Sensor module; 10. Air pressure balance valve. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] Specific embodiments of the multi-factor coupled aging test device for asphalt pavement proposed in this invention: like Figure 1 As shown, the asphalt pavement multi-factor coupled aging test device includes a test chamber 1 and a simulated traffic load system 3, a water spray circulation system 4, an ultraviolet lamp group, a heating and airflow circulation system 6, a sample holding platform 7, and a sensor module 9 installed inside the test chamber 1.

[0031] The interior of the test chamber 1 is divided into two parts along the vertical direction: the upper part is the transmission area, which is used to arrange precision transmission components; the lower part is the test chamber, which is used to construct a multi-factor coupled aging environment.

[0032] like Figure 1 As shown, a base 8 is fixed to the bottom of the test chamber 1. Two parallel, spaced-apart support columns 2 are mounted on the base 8. The support columns 2 extend upwards through the test chamber and into the upper transmission area. The support columns 2 have a certain width for installation and load-bearing. In this embodiment, the test chamber 1 adopts a double-layer insulation structure. The inner wall is made of corrosion-resistant stainless steel, and the outer layer is made of cold-rolled steel plate, with polyurethane insulation material filling the middle to reduce heat loss within the chamber. Figure 2As shown, a closable door 11 is provided on one side of the test chamber 1, corresponding to the test compartment. A ring-shaped silicone sealing strip is installed around the door 11 where it connects to the chamber, creating a closed space when the door 11 is closed. A flexible diaphragm, resistant to high temperatures, ultraviolet radiation, and humidity, is installed on the inside of the door 11. When the door 11 is opened, it prevents the leakage of hot and humid air from the chamber, ensuring operational safety. In practical use, the flexible diaphragm can be a silicone soft curtain, a polytetrafluoroethylene (PTFE) soft film, or a specially treated high-temperature resistant PVC soft board. Because it is flexible, when operators need to place or remove asphalt mixture specimens, they only need to use their hands or tools to open, lift, or pass the soft curtain directly through. After the removal is completed, the flexible diaphragm will naturally droop back to its closed state under its own weight. A high-temperature tempered glass observation window 12 is provided in the middle of the door 11, allowing operators to observe the condition of the specimens inside the test chamber. The upper part of the outer side wall of the test chamber 1 is equipped with a display screen 13 and operation buttons 14, which are used to input test parameters, display operating data, and control the start and stop of the device.

[0033] like Figure 1 and Figure 3 As shown, the simulated vehicle load system 3 is installed in the upper transmission area and mainly includes a horizontal reciprocating motion mechanism 31, a vertical loading mechanism 32, and a loading roller 33. The horizontal reciprocating motion mechanism 31 adopts a screw and nut transmission mechanism, including a first servo motor 311, a drive screw 312, and a nut seat 313. The first servo motor 311 is fixed relative to the support column 2, and its output end is connected to the drive screw 312. The drive screw 312 is arranged in the horizontal direction and fixed at both ends by screw support seats. The nut seat 313 is threaded onto the drive screw 312. When the first servo motor 311 runs, it drives the drive screw 312 to rotate, thereby driving the nut seat 313 to perform linear reciprocating motion along the axial direction of the drive screw 312.

[0034] The vertical loading mechanism 32 includes a second servo motor 321, a transmission shaft 322, a reversing gear set 323, a guide shaft 324, a connecting plate 325, and an electric cylinder 326. The reversing gear set 323 is a common bevel gear reversing structure in the prior art. The housing of the reversing gear set 323 is fixedly connected to the nut seat 313 via a vertical connecting rod 327 and moves horizontally synchronously with the nut seat 313. A guide rail 34 parallel to the drive screw 312 is provided on the support column 2 below it. A slider 328 that slides with the guide rail 34 is connected to the vertical connecting rod 327. The second servo motor 321 is fixedly mounted on the connecting plate 325. The guide shaft 324 passes through the support column 2 in the horizontal direction and slides with the support column 2. One end of the guide shaft 324 is fixedly connected to the connecting plate 325, and the other end is fixedly connected to the housing of the reversing gear set 323. The support column 2 not only bears the overall weight of the second servo motor 321 and its supporting transmission components, but also provides horizontal motion guidance for the entire vertical loading mechanism 32, ensuring the smoothness of reciprocating motion. The output shaft of the second servo motor 321 is connected to the horizontal input end of the reversing gear set 323 through the transmission shaft 322. The vertical output end of the reversing gear set 323 is connected to the input end of the electric cylinder 326, which can convert the horizontal axial rotational motion output by the second servo motor 321 into vertical axial rotational motion, thereby driving the electric cylinder 326 to complete the vertical extension and retraction action. The support column 2 is provided with a clearance opening to avoid the transmission shaft 322. The loading roller 33 is located in the test chamber and is rotatably mounted on the bottom end of the output rod of the electric cylinder 326. It rises and falls synchronously with the electric cylinder 326. When the electric cylinder 326 extends downward, it drives the loading roller 33 to press the surface of the asphalt mixture specimen, applying a stable and controllable vertical load.

[0035] The horizontal reciprocating motion mechanism 31 and the vertical loading mechanism 32 work together to make the loading roller 33 press the specimen with a set pressure while rolling back and forth along the surface of the asphalt mixture specimen, thereby replicating the dynamic compaction effect of the current vehicle load on the road surface.

[0036] like Figure 1 and Figure 8As shown, a sample holding platform 7 is located at the bottom of the test chamber, below the loading roller 33. The sample holding platform 7 mainly includes a sample carrier 71, a tray 72, and a support platform 73. The support platform 73 is installed above the base 8. The tray 72 is rotatably mounted at the center of the support platform 73 via a rotating shaft 74. The sample carrier 71 is fixedly installed on the upper surface of the tray 72 to support the asphalt mixture specimen. The test chamber also has a rotary drive mechanism for driving the tray 72 to rotate. The rotary drive mechanism includes a third servo motor 76 and a transmission gear set 77. The third servo motor 76 is arranged on the side of the support platform 73. The transmission gear set 77 is integrally mounted on the support platform 73 and is also a bevel gear reversing structure. The output end of the third servo motor 76 is connected to the input end of the transmission gear set 77. An annular gear ring is provided on the outer periphery of the tray 72. The output gear part of the transmission gear set 77 extends out of the housing of the transmission gear set 77 and meshes with the annular gear ring. When the third servo motor 76 operates, it drives the tray 72 and the sample stage 71 to rotate uniformly around the shaft 74 via the transmission gear set 77, ensuring that the specimen receives uniform ultraviolet irradiation and spraying in the circumference. As the sample stage 71 rotates, it can rotate the specimen to different angles, allowing the loading roller 33 to press the specimen from different directions. The rotation of the sample stage 71 and the loading of the loading roller 33 are not synchronized.

[0037] The sample platform 71, tray 72, and support platform 73 are all equipped with vertically penetrating flow channels 75, allowing water generated by spraying to drain quickly downwards through these channels, preventing water accumulation on the surface of the asphalt mixture specimens. A water collection trough 46 is located below the support platform 73, fixedly installed inside the base 8, with its opening directly opposite the flow channel holes 75 of the support platform 73, to collect water flowing down from above. A sieve is laid above the water collection trough 46, completely covering all the flow channel holes 75 of the support platform 73, preventing aggregate particles and other debris from falling from the specimens and preventing particles from entering the water collection trough 46 and clogging the circulating water path.

[0038] like Figure 1 , Figure 4 and Figure 5As shown, the water spray circulation system 4 mainly includes a water pipe 41, a water pump 42, a water distribution connector 43, a high-pressure micro-mist humidifier 44, a high-pressure nozzle 45, and a water supply valve 47. The water pump 42 is fixedly installed on the side of the test chamber 1. Its inlet end is connected to the bottom of the water collection tank 46 through the water pipe 41, and its outlet end is connected to the water distribution connector 43 through the water pipe 41. The water distribution connector 43 divides the water path into two paths, each equipped with a high-pressure micro-mist humidifier 44 and a high-pressure nozzle 45. The high-pressure micro-mist humidifier 44 is used to deliver fine water mist into the test chamber, thereby regulating the air humidity inside the test chamber. The high-pressure nozzle 45 is positioned facing the center of the sample platform 71 and is used to directly spray water onto the surface of the asphalt mixture specimen. A water supply valve 47 is connected to the side of the water collection tank 46. The outer end of the water supply valve 47 extends to the outside of the test chamber 1. It can be used to manually replenish the test water into the water collection tank 46, or to drain the wastewater in the tank after the test, which is convenient for cleaning and maintenance of the device.

[0039] like Figure 1 and Figure 6 As shown, the ultraviolet lamp assembly is installed on the top inner wall of the test chamber, arranged in a staggered pattern around the loading roller 33. It includes multiple UVA and UVB type ultraviolet lamps 5, each of which is equipped with a high-temperature resistant quartz glass protective cover. The irradiation intensity of the ultraviolet lamps 5 can be adjusted by the control system, radiating ultraviolet light downwards to provide an adjustable intensity ultraviolet aging environment for the asphalt mixture specimens.

[0040] like Figure 1 and Figure 7 As shown, the heating and airflow circulation system 6 includes a fan 61, a flow equalization plate 62, a baffle 63, a heating rod 64, an inlet duct 67, and a return duct 66. The flow equalization plate 62 and the baffle 63 enclose an independent heat exchange chamber on one side wall of the test chamber. The heating rod 64, as a heating element, is electrically heated and is fixedly installed inside the baffle 63 and located inside the heat exchange chamber. The fan 61 is arranged outside the heat exchange chamber, with its inlet end connected to the return duct 66 and its outlet end connected to the heat exchange chamber. The inlet duct 67 is arranged vertically and opposite to the flow equalization plate 62, while the return duct 66 is connected to the bottom of the inlet duct 67 and is arranged horizontally. The sample holding platform 7 is located in the area between the inlet duct 67 and the flow equalization plate 62, and multiple air inlets 65 are opened on the side of the inlet duct 67 facing the sample holding platform 7.

[0041] When the blower 61 is running, it draws air from the test chamber through the return air duct 66, pressurizes it, and sends it into the heat exchange chamber. As the air flows past the heating rod 64, it absorbs heat to form a hot airflow. After being homogenized and rectified by the flow equalization plate 62, the hot airflow is steadily delivered into the core working area of ​​the test chamber with uniform wind speed and temperature, uniformly heating the environment and asphalt mixture specimens within the test chamber. After completing heat exchange and cooling in the working area, the hot airflow enters the return air duct 66 through the air inlet 65 on the other side and flows back to the air inlet of the blower 61, thus forming a closed-loop hot air circulation. This continuously maintains the high-temperature environment within the test chamber while ensuring a uniform temperature distribution and preventing localized temperature differences.

[0042] Sensor module 9, located on the inner wall of the test chamber, includes a temperature sensor, a humidity sensor, and an ultraviolet radiometer. These sensors are used to collect real-time data on temperature, humidity, and ultraviolet radiation intensity within the test chamber and transmit the data to the control system. The control system dynamically adjusts the operating parameters of the corresponding components based on the collected real-time data, thereby controlling the environment within the test chamber and ensuring that all environmental parameters remain stable within the set range. A pressure balancing valve 10 is also installed on the side wall of the test chamber body 1. This valve monitors the air pressure within the test chamber in real time and automatically opens to release air when the air pressure exceeds a set threshold, maintaining stable internal air pressure and preventing safety hazards caused by excessive pressure.

[0043] The working process of the asphalt pavement multi-factor coupled aging test device of the present invention is as follows: During the test preparation phase, the operator opens the chamber door 11 and places the pre-formed asphalt mixture specimen at the center of the sample loading platform 71. Various test parameters and safety protection thresholds are input via the operation button 14, and the control system generates the operating program based on the input parameters. After starting the test apparatus, the heating and airflow circulation system 6 is activated, and the fan 61 and heating rod 64 work together to gradually raise the temperature inside the test chamber to the preset value and maintain stability. Simultaneously, the high-pressure micro-mist humidifier 44 of the water spray circulation system 4 is activated, delivering water mist into the test chamber to adjust the air humidity to the set range. During this process, the rotary drive mechanism drives the tray 72 to rotate, ensuring that the specimen is evenly irradiated, evenly heated, and evenly sprayed.

[0044] After the temperature and humidity inside the test chamber stabilize, the simulated vehicle load system 3 is activated. At this time, the rotary drive mechanism stops operating, and the first servo motor 311 drives the vertical loading mechanism 32 to perform periodic reciprocating motion in the horizontal direction. Simultaneously, the second servo motor 321 drives the electric cylinder 326 to extend downward through the reversing gear set 323, causing the loading roller 33 to press the surface of the asphalt mixture specimen with a set pressure. During the reciprocating motion, the loading roller 33 rolls along the surface of the specimen, forming a dynamic reciprocating rolling vehicle load effect. Then, the ultraviolet lamp 5 and the high-pressure nozzle 45 are turned on synchronously. The ultraviolet lamp 5 outputs ultraviolet radiation of a set intensity to irradiate the specimen, and the high-pressure nozzle 45 continuously sprays water onto the surface of the asphalt mixture specimen, making the surface and internal pores of the asphalt mixture specimen saturated with water. During the rolling process, the loading roller 33 squeezes the water on the surface and in the pores of the asphalt mixture specimen, generating a dynamic water pressure scouring effect.

[0045] During the test run, sensor module 9 collects various environmental parameters in real time and feeds them back to the control system. The control system dynamically adjusts the operating power of each component to maintain stable environmental parameters inside the test chamber. Display screen 13 displays temperature and humidity curves, pressure curves, loading times, ultraviolet irradiance curves, and remaining time in real time, facilitating operator monitoring of the test status. If abnormal conditions such as abnormal pressure or excessively high temperature occur during operation, the device can automatically trigger shutdown protection. Operators can also manually press the stop button to interrupt operation and open the chamber door 11 for inspection after the parameters inside the test chamber return to normal. After the test reaches the set duration, the system automatically stops the ultraviolet lamp 5, the simulated traffic load system 3, the high-pressure nozzle 45, and the heating rod 64 according to the program, while the fan 61 continues to run to accelerate the cooling of the test chamber. After the temperature inside the test chamber drops to room temperature, operators can open the chamber door 11 to remove the aged asphalt mixture specimens.

[0046] In the above embodiments, the horizontal reciprocating motion mechanism adopts a screw and nut transmission mechanism. In other embodiments, the horizontal reciprocating motion mechanism can also adopt a synchronous belt transmission mechanism, in which the first servo motor 311 drives the active synchronous pulley to drive the closed synchronous belt to rotate; the vertical loading mechanism 32 is fixed on the surface of the synchronous belt and rotates with the synchronous belt to achieve horizontal reciprocating motion. The transmission process is smooth and low-noise, which is suitable for the requirements of long-stroke compaction tests.

[0047] In the above embodiments, the heating element in the heat exchange chamber is a heating rod 64; in other embodiments, the heating element can also be a PTC heating element. The PTC heating element has a positive temperature coefficient characteristic. The output power automatically decreases after the temperature rises, which can realize self-limiting temperature protection. It has a larger heat exchange area, a more uniform heating process, and can improve the temperature stability in the test chamber.

[0048] In the above embodiments, the vertical loading mechanism 32 adopts a reversing transmission structure in which the second servo motor 321 and the reversing gear set 323 drive the electric cylinder 326. In other embodiments, under the condition of sufficient vertical space, the vertical loading mechanism 32 can also adopt a direct-drive servo electric cylinder structure, in which the second servo motor 321 and the electric cylinder 326 are arranged coaxially in the vertical direction, and the output shaft of the second servo motor 321 is directly connected to the transmission screw of the electric cylinder 326. At this time, the second servo motor 321 is directly fixed to the lower end of the vertical connecting rod 327, and directly drives the electric cylinder 326 to complete the vertical extension and load application, eliminating the reversing transmission link, resulting in higher transmission efficiency and a more compact overall structure.

[0049] An embodiment of the multi-factor coupled aging test method for asphalt pavement proposed in this invention: The multi-factor coupled aging test method for asphalt pavement is based on the multi-factor coupled aging test device for asphalt pavement described in the above embodiments, and includes the following steps: Step S1: Prepare shaped asphalt mixture specimens and blank control group specimens.

[0050] First, test specimens are prepared. Asphalt mixture specimens are formed according to the relevant methods in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG 3410-2025). Marshall specimens, rutting slab specimens, or other non-standard parts of the same specifications can be used for asphalt mixture specimens. At the same time, blank control group specimens of the same specifications are prepared for subsequent performance comparison analysis.

[0051] Step S2: Obtain actual meteorological data of the test area, divide the annual meteorological data into multiple natural stages, and calculate the test parameters corresponding to each natural stage. The test parameters include indoor simulated ultraviolet light duration, test temperature, spray volume, ambient humidity, loading pressure and loading rate.

[0052] As one implementation method, long-term meteorological observation data of the target test area is first obtained, and the whole year is divided into four stages based on seasonal meteorological characteristics, corresponding to June to August, September to November, December to February, and March to May, respectively. Then, the ultraviolet light duration, test temperature, spray volume, ambient humidity, loading pressure, and loading rate are determined for each stage.

[0053] Since there are differences between indoor simulated ultraviolet (UV) light and outdoor natural sunlight UV light, the duration of indoor UV light exposure can be calculated using the following formula:

[0054] In the formula: Z represents the simulated indoor ultraviolet radiation duration, in hours; Z represents the solar ultraviolet radiation duration, in hours; Y represents the solar ultraviolet radiation intensity, taken as 0.52 W / m². 2X represents the indoor ultraviolet radiation intensity, which can be measured by an ultraviolet radiometer. This formula is an existing formula, derived from the literature "Equivalent Conversion Study of Indoor and Outdoor Ultraviolet Aging Time of Asphalt" published in the journal "Highway and Transportation".

[0055] The test temperature for each stage is calculated using the following formula:

[0056] In the formula, The test temperature is expressed in °C. The solar absorptivity and radiation absorptivity of different material surfaces are taken as 0.65~0.80; J is the solar radiation intensity, taken as 710 kcal / m². 2 ·h; The radioactivity coefficient is taken as 20 kcal / m². 2 ·h·℃; This represents the actual pavement temperature. This formula is an existing formula, derived from the literature "Research on Accelerated Simulation Test Method and Evaluation Index of Multi-Factor Coupled Aging of Asphalt".

[0057] The formulas for calculating the spray volume at each stage are as follows:

[0058] In the formula, q is the spray volume in ml; H is the average daily rainfall in mm; and S is the spray area in mm. 2 This formula is a general formula for calculating the spray volume. During the experiment, the spray was applied evenly multiple times within each stage of the test duration to simulate the scouring effect of natural rainfall.

[0059] The ambient humidity at each stage can be taken as the average humidity value of the target test area at each stage.

[0060] The determination of loading pressure and loading rate refers to the standard provisions of T0719 Asphalt Mixture Rutting Test in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG 3410-2025).

[0061] Step S3: Fix the asphalt mixture specimen at the center of the sample holding platform, adjust the initial distance between the loading roller and the asphalt mixture specimen, and set the test parameters; Step S4: Start the test device. First, adjust the temperature and humidity in the test chamber to the preset value through the heating and air circulation system and the water spray circulation system. Then, start the ultraviolet lamp group and the simulated vehicle load system to make the loading roller reciprocate to roll the asphalt mixture specimen. At the same time, the water spray circulation system sprays water onto the surface of the asphalt mixture specimen to form a multi-factor coupled aging environment. Step S5: After the test, start the cooling program. After the temperature in the test chamber drops to room temperature, take out the asphalt mixture specimens and perform performance tests on the aged asphalt mixture specimens and the blank control group specimens to analyze the influence of multi-factor coupled aging on the performance of asphalt mixtures.

[0062] The following uses meteorological statistics data from four stages in a certain region as an example to further illustrate the experimental method of the present invention.

[0063] Table 1 shows the meteorological statistics for a certain region in four stages.

[0064] As shown in Table 1, when the irradiance of the ultraviolet lamp is set to 100W / m 2 At that time, the ultraviolet irradiance near the sample stage was 8.2 W / m², obtained by ultraviolet radiometer. 2 Based on the formula above, the indoor ultraviolet light exposure time for each stage is calculated to be 52h (June-August), 49h (September-November), 37h (December-February), and 32h (March-May).

[0065] Substituting the average temperature of each stage in the table above into the experimental temperature calculation formula, we can obtain the experimental temperatures of each stage as 60℃ (June to August), 50℃ (September to November), 29℃ (December to February), and 47℃ (March to May).

[0066] The spray volume calculation formula yields the following spray volumes for each period: 540ml (June-August), 360ml (September-November), 240ml (December-February), and 540ml (March-May). Meteorological data shows that the average ambient humidity for each period is 83% (June-August), 75% (September-November), 70% (December-February), and 82% (March-May).

[0067] Referring to the standard provisions of T0719 Rutting Test of Asphalt Mixture in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG 3410-2025), the contact pressure was determined to be 0.7 MPa and the loading rate was 42 times / minute (one round trip is counted as one time, i.e., 21 round trips / minute).

[0068] The overall experimental plan is shown in Table 2: Table 2 shows the multi-factor coupled aging test scheme for one cycle (4 stages).

[0069] After inputting the test parameters according to the above test plan, the control system will automatically generate a control program based on the test parameters; set safety protection values, including high temperature alarm, overpressure alarm, and water level alarm. Then press the start button to start the test device and carry out the aging test according to the steps of the control program. After the test is completed, the control system will automatically stop working and start the cooling function. After the temperature drops to room temperature, open the chamber door and take out the asphalt mixture specimen.

[0070] Asphalt mixture specimens underwent a three-cycle coupled aging test involving damp heat, ultraviolet radiation, traffic load, and load-induced water pressure. Following the initial aging test, the asphalt mixture specimens (including the blank group) were subjected to Marshall tests, rutting tests, dynamic modulus tests, and low-temperature bending tests according to the experimental methods in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG 3410-2025). Data before and after aging were compared to analyze the impact of multi-factor simulated aging (damp heat, strong ultraviolet radiation, traffic load, and load-induced water pressure) on the performance of the mixture. The test results of the asphalt mixture performance before and after aging are shown in Table 3. Table 3 shows the performance test results of asphalt mixtures before and after aging.

[0071] The test results in the table show that with the increase of the multi-factor coupled aging cycle, the asphalt mixture exhibits a clear evolution pattern of hardening and damage intertwined. This verifies that the test device of this invention can effectively simulate the real road service environment. Specifically, under the continuous influence of damp heat and strong ultraviolet radiation, the asphalt material gradually hardens and becomes brittle, which is directly manifested as a continuous increase in dynamic modulus, while the flow value and low-temperature bending failure strain continuously decrease. At one aging cycle, the asphalt mixture specimens show a brief peak increase in Marshall stability and rutting dynamic stability due to the hardening of the asphalt. However, as the aging cycle continues to increase, the scouring and destructive effects of factors such as dynamic reciprocating traffic loads and load-induced dynamic water pressure begin to dominate, leading to spalling and fatigue damage at the asphalt-aggregate interface. This results in a significant decrease in Marshall stability, rutting dynamic stability, and residual strength ratio and residual stability, which reflect the water stability of the material. This data trend reveals the actual damage pattern of asphalt pavement under long-term combined action of light, heat, water, and force, from initial material hardening to later structural loosening, cracking, and decay. It proves that the test device of this invention can accurately and scientifically evaluate the long-term durability of asphalt mixtures under multiple harsh environments.

[0072] While various embodiments of the invention have been shown and described in this specification, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention.

Claims

1. A multi-factor coupled aging test device for asphalt pavement, characterized in that, include: The test chamber contains a test compartment. The simulated vehicle load system is set inside the test chamber and includes a horizontal reciprocating motion mechanism, a vertical loading mechanism, and a loading roller. The vertical loading mechanism is connected to the output end of the horizontal reciprocating motion mechanism, and the loading roller is connected to the output end of the vertical loading mechanism and located inside the test chamber. It is used to press down on and contact the asphalt mixture specimen to apply a dynamic reciprocating rolling load to it. The sample holding platform, located at the bottom of the test chamber, is used to support asphalt mixture specimens; The water spraying circulation system is installed inside the test chamber and above the sample holding platform. It is used to spray water mist onto the surface of the asphalt mixture specimen and regulate the humidity of the test chamber. It works in conjunction with the reciprocating rolling action of the loading roller to squeeze out the accumulated water and generate dynamic water pressure. An ultraviolet lamp assembly, located at the top of the test chamber and above the sample holding platform, is used to provide an adjustable intensity ultraviolet radiation environment to the asphalt mixture specimens. A heating and airflow circulation system is installed inside the test chamber to provide a stable and uniform high-temperature environment for aging tests.

2. The asphalt pavement multi-factor coupled aging test device according to claim 1, characterized in that, The horizontal reciprocating motion mechanism is a lead screw and nut transmission mechanism, including a first servo motor, a drive lead screw that is driven by the first servo motor, and a nut seat that is threaded onto the drive lead screw. The vertical loading mechanism is connected to the nut seat.

3. The asphalt pavement multi-factor coupled aging test device according to claim 2, characterized in that, The vertical loading mechanism includes a second servo motor, a reversing gear set, and an electric cylinder. The output shaft of the second servo motor is connected to the horizontal input end of the reversing gear set, and the vertical output end of the reversing gear set is connected to the input end of the electric cylinder. A vertical connecting rod is connected between the housing of the reversing gear set and the nut seat. The loading pressure roller is rotatably mounted on the output rod of the electric cylinder. The second servo motor is connected to the housing of the reversing gear set through multiple guide shafts.

4. The asphalt pavement multi-factor coupled aging test device according to claim 3, characterized in that, The test chamber is equipped with a base and a support column connected to the base. The test chamber is located above the base, and the support column passes through the test chamber. The support column is connected to guide rails that are parallel to the drive screw and arranged at intervals in the vertical direction. The vertical connecting rod is equipped with a slider that slides with the guide rails. The guide shaft slides with the support column in the horizontal direction.

5. A multi-factor coupled aging test device for asphalt pavement according to any one of claims 2-4, characterized in that, The sample holding platform includes a sample carrier, a tray, and a support platform. The sample carrier, tray, and support platform are all porous structures and have through-flow channels. The sample carrier is used to place the asphalt mixture specimen. The sample carrier is fixed on the tray, and the tray is rotatably mounted on the support platform. The test chamber is also equipped with a rotary drive mechanism for driving the tray to rotate. A water collection tank communicating with the flow channels is provided below the support platform, and a screen is also provided above the water collection tank. The screen covers at least each flow channel on the support platform.

6. The asphalt pavement multi-factor coupled aging test device according to claim 5, characterized in that, The heating and airflow circulation system includes a heat exchange chamber surrounded by a flow equalization plate and a baffle, a heating element located inside the heat exchange chamber and fixed on the baffle, and a fan, a return air duct, and an inlet air duct located outside the heat exchange chamber. The return air duct is connected to the inlet air duct, the inlet end of the fan is connected to the return air duct, and the outlet end of the fan is connected to the heat exchange chamber. The heat exchange chamber is arranged on the side wall of the test chamber, and the sample holding platform is located between the inlet air duct and the heat exchange chamber. The inlet air duct is provided with multiple air inlets facing the flow equalization plate.

7. The asphalt pavement multi-factor coupled aging test device according to claim 5, characterized in that, The water spray circulation system includes a water pump, a water pipe, and a high-pressure micro-mist humidifier and a high-pressure nozzle installed on the water pipe; the water outlet of the water pump is connected to the water pipe, the water inlet of the water pump is connected to the water collection tank, and a water supply valve is also connected to the water pipe.

8. The asphalt pavement multi-factor coupled aging test device according to claim 1, characterized in that, The test chamber is divided into upper and lower parts. The upper part is the transmission area that houses the transmission components of the simulated vehicle load system, and the lower part is the test chamber. The test chamber is equipped with a door corresponding to the position of the test chamber, and the inside of the door is equipped with a flexible diaphragm to prevent the leakage of high temperature and humid airflow.

9. The multi-factor coupled aging test device for asphalt pavement according to claim 1, characterized in that, It also includes a sensor module and a pressure balancing valve; the sensor module includes a temperature sensor, a humidity sensor and an ultraviolet radiometer installed in the test chamber, which are used to monitor the environmental parameters in the test chamber in real time; the pressure balancing valve is used to monitor the real-time air pressure inside the test chamber and automatically release air to maintain the stability of the internal air pressure when the air pressure is too high.

10. A multi-factor coupled aging test method for asphalt pavement, characterized in that, The asphalt pavement multi-factor coupled aging test device according to any one of claims 1-9 includes the following steps: Step S1: Prepare shaped asphalt mixture specimens and blank control group specimens; Step S2: Obtain actual meteorological data of the test area, divide the annual meteorological data into multiple natural stages, and calculate the test parameters corresponding to each natural stage. The test parameters include indoor simulated ultraviolet light duration, test temperature, spray volume, ambient humidity, loading pressure and loading rate. Step S3: Fix the asphalt mixture specimen in the center of the sample holding platform, adjust the initial distance between the loading roller and the asphalt mixture specimen, and set the test parameters; Step S4: Start the test device. First, adjust the temperature and humidity in the test chamber to the preset value through the heating and air circulation system and the water spray circulation system. Then, start the ultraviolet lamp group and the simulated vehicle load system to make the loading roller reciprocate to roll the asphalt mixture specimen. At the same time, the water spray circulation system sprays water onto the surface of the asphalt mixture specimen to form a multi-factor coupled aging environment. Step S5: After the test, start the cooling program. After the temperature in the test chamber drops to room temperature, take out the asphalt mixture specimens and perform performance tests on the aged asphalt mixture specimens and the blank control group specimens to analyze the influence of multi-factor coupled aging on the performance of asphalt mixtures.

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