Testing device and method for evaluating salt corrosion resistance of asphalt mixture

Abstract

The invention relates to the technical field of highway engineering test equipment, and discloses a test device and method for evaluating the salt corrosion resistance of an asphalt mixture, the test device comprises a test device shell, the interior of the test device shell is fixedly connected with a test platform, and the top of the test platform is fixedly connected with a fixed plate; a control device is fixedly connected to the side face of the testing device shell, a supporting device is fixedly connected to the top of the control device, a hydraulic device is movably connected to the bottom of the supporting device, a connecting rod is fixedly connected to the bottom of the hydraulic device, and a washing device and a separating device are fixedly connected to the connecting rod. A partition plate is fixedly connected in the test device shell, and a heating device is arranged in the test device shell; the detection device is arranged, so that the surface of the test piece before and after the test can be detected, and the state data of the test piece subjected to salt corrosion under different conditions can be obtained through comparison, so that the state of the test subjected to salt corrosion can be more clearly shown.

Description

Technical Field

[0001] The present invention relates to the technical field of highway engineering test equipment, and specifically provides a test device and method for evaluating the salt erosion resistance performance of asphalt mixtures. Background Art

[0002] An asphalt mixture is a composite material mainly composed of asphalt, coarse aggregates, fine aggregates, fillers, etc. Mixing these materials with different qualities and quantities can form different structures and have different mechanical properties. The water erosion of asphalt mixtures is an important cause of the damage to asphalt pavements. At present, asphalt mixtures are widely used in highway pavement paving projects, and water erosion has an important impact on the service performance and service life of pavement structures. Therefore, it is of great significance to comprehensively evaluate the water erosion of asphalt mixtures.

[0003] The patent with publication number CN107843723A discloses a multi-factor coupling test device for dynamic load - salt - water - temperature of asphalt mixtures, including a box body. A test bench is provided at the bottom of the box body, a frame plate is provided at the upper part of the box body, and a motor is provided at the top of the box body. The main shaft of the motor passes through the frame plate and extends downward into the box body; a test wheel set is located between the frame plate and the test bench. The test wheel set includes two cross-connected axle shafts and rubber rollers at both ends of the axle shafts. A rotating shaft is also provided at the cross-connection of the two axle shafts, and a pressure plate is sleeved on the rotating shaft; the upper end of the transmission sleeve is in transmission connection with the main shaft of the motor, and the lower end of the transmission sleeve is in transmission connection with the rotating shaft; hydraulic cylinders are distributed around the transmission sleeve. The cylinder body of the hydraulic cylinder is connected to the frame plate, and a disc pressure bearing is provided between the end of the piston rod of the hydraulic cylinder and the pressure plate. It also discloses a test method based on this device. This device and its test method can preferably simulate the performance damage and deterioration process of asphalt mixtures under the coupling action of multiple factors.

[0004] When the above device detects the salt erosion resistance performance of asphalt mixtures, the damage caused by the multi-factor coupling of asphalt mixtures is reflected by the distance of downward displacement at the bottom of the asphalt mixture in the salt erosion state. The displacement distance itself is relatively small during the test, and the detection result is not obvious when detected by a displacement sensor. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a test device and method for evaluating the salt erosion resistance performance of asphalt mixtures to solve the problems existing in the above background art.

[0006] The present invention provides the following technical solution: An experimental device for evaluating the anti-salt corrosion performance of asphalt mixtures, including an outer shell of the experimental device. Inside the outer shell of the experimental device, there is a fixed connection with an experimental platform. On the top of the experimental platform, there is a fixed connection with a fixing plate. Inside the fixing plate is used to store asphalt mixture specimens. On the side of the outer shell of the experimental device, there is a fixed connection with a control device. On the top of the control device, there is a fixed connection with a support device. At the bottom of the support device, there is a movable connection with a hydraulic device. At the bottom of the hydraulic device, there is a fixed connection with a connecting rod. On the connecting rod, there are fixed connections with a scouring device and a partitioning device. The scouring device is used to scour the specimens, and the partitioning device is used to partition the specimens into multiple areas. At the bottom of the outer shell of the experimental device, there is a storage box opened. Inside the outer shell of the experimental device, there is a fixed connection with a partition plate. The storage box is partitioned into multiple areas by the partition plate. Inside the outer shell of the experimental device, there is a heating device. The heating device is electrically connected to the control device. The heating device is used to heat the inside of the storage box. On the side of the outer shell of the experimental device, there is a fixed connection with a detection device for detecting the experimental results.

[0007] Further, on the side of the experimental platform, there is a fixed connection with a drainage plate. The drainage plate has a structure with higher sides and a lower middle. At the center of the drainage plate, there is a water passing hole opened. The water passing hole communicates with the storage box arranged at the bottom, which is more convenient for collecting the sprayed brine. The brine flows into the inside of the storage box through the water passing hole.

[0008] Further, the storage box is arranged below the scouring nozzles. The number of partitions of the storage box is the same as the number of scouring devices. At the bottom of the storage box, there is a flowing water pipe opened. The flowing water pipe communicates with the control device. The heating device is arranged on the side of the storage box. At the flowing water pipe, there is a filter screen to avoid impurities entering and blocking the inside.

[0009] Further, on the bottom surface of the scouring device, there is a fixed connection with a scouring nozzle. The scouring nozzle is used for spraying brine.

[0010] Further, the partitioning device includes a connecting plate. On the top of the connecting plate, there is a fixed connection with a connecting block. Inside the connecting block, there is a suction and exhaust device arranged. On the bottom of the connecting plate, there is a connecting groove opened. On the connecting groove, there is a ventilation pipe opened. The suction and exhaust device communicates with the ventilation pipe. When the connecting plate contacts the specimen, the suction and exhaust device arranged inside the connecting block starts, inhaling air inward from the ventilation pipe opened at the bottom of the connecting block, so that a negative pressure is generated at the place where the connecting groove opened on the connecting plate contacts the specimen, and the connecting plate tightly adsorbs on the specimen, preventing the mixing of brines with different concentrations during the test and affecting the test results.

[0011] Further, a connecting shaft is fixedly connected to the bottom of the connecting rod. A connecting sleeve is fixedly connected to the bottom of the connecting shaft. A pressing block is fixedly connected to the bottom of the connecting sleeve. A roller is rotatably connected to the side of the connecting sleeve. A roller groove is formed in the roller. A motor is arranged inside the connecting shaft, and the motor drives the roller and the roller groove to rotate.

[0012] Further, a cover plate is arranged on the top of the test device housing. The cover plate is movably connected to the test device housing. A handle is fixedly connected to the top of the cover plate. An observation window is fixedly connected to the front side of the test device housing. Both the observation window and the cover plate are made of transparent materials.

[0013] The detection device includes a detection unit, a preprocessing unit, a processing unit, and a feedback unit.

[0014] A method for using a test device for evaluating the salt erosion resistance of asphalt mixtures, the method comprising:

[0015] S1: Place the prepared specimen in a fixed mold, detect the surface of the specimen through a detection device, and fix the specimen by moving downward through a hydraulic device;

[0016] S2: Change the temperature of the brine inside the device, adjust and control the concentration of the brine inside, and at the same time adjust the rotation speeds of the roller and the pressing block and the water flow rate, and conduct multiple tests;

[0017] S3: Detect the surface of the specimen again, and evaluate the salt erosion resistance of the specimen based on the detection results.

[0018] Beneficial effects:

[0019] 1. For the test device and method for evaluating the salt erosion resistance of asphalt mixtures, when in use, the motor drives the roller and the pressing block to rotate, simulating the friction of the vehicle on the bottom surface. At the same time, the brine flows from the roller groove on the roller to the specimen, which can better simulate the actual use situation during the test, and the test effect is better. There are also multiple detection areas, which is more convenient for conducting control tests.

[0020] 2. For the test device and method for evaluating the salt erosion resistance of asphalt mixtures, a detection device is provided, which can detect the surface of the specimen before and after the test. By comparison, the state data of the specimen being salt eroded under different conditions can be obtained, so as to more clearly show the state after the test specimen is salt eroded. Description of the drawings

[0021] Figure 1 It is a schematic structural diagram of a test device for evaluating the salt erosion resistance of asphalt mixtures proposed by the present invention;

[0022] Figure 2Schematic structural diagram of a test device for evaluating the salt corrosion resistance of asphalt mixtures proposed by the present invention;

[0023] Figure 3 Schematic structural diagram of the partition device and the scouring device of a test device for evaluating the salt corrosion resistance of asphalt mixtures proposed by the present invention;

[0024] Figure 4 Schematic structural diagram of the scouring device of a test device for evaluating the salt corrosion resistance of asphalt mixtures proposed by the present invention;

[0025] Figure 5 Schematic structural diagram of the connection structure between the roller and the pressing block of a test device for evaluating the salt corrosion resistance of asphalt mixtures proposed by the present invention.

[0026] Wherein: 1. Outer shell of the test device; 2. Observation window; 3. Partition device; 301. Connection plate; 302. Connection block; 303. Connection groove; 304. Vent pipe; 4. Scouring device; 5. Hydraulic device; 6. Control device; 7. Support device; 8. Handle; 9. Cover plate; 10. Fixed plate; 11. Scouring nozzle; 12. Heating device; 13. Partition board; 14. Drainage plate; 15. Test platform; 16. Storage tank; 17. Water pipe; 18. Connecting rod; 19. Connecting shaft; 20. Connecting sleeve; 21. Roller; 22. Pressing block; 23. Roller groove; 24. Detection device. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1

[0029] Please refer to Figures 1 - 5, a test device for evaluating the salt corrosion resistance of asphalt mixtures, comprising a test device housing 1. Inside the test device housing 1, a test platform 15 is fixedly connected. On the top of the test platform 15, a fixing plate 10 is fixedly connected. The inside of the fixing plate 10 is used to store asphalt mixture specimens. On the side of the test device housing 1, a control device 6 is fixedly connected. On the top of the control device 6, a support device 7 is fixedly connected. At the bottom of the support device 7, a hydraulic device 5 is movably connected. At the bottom of the hydraulic device 5, a connecting rod 18 is fixedly connected. On the connecting rod 18, a flushing device 4 and a partitioning device 3 are fixedly connected. The flushing device 4 is used to flush the specimens, and the partitioning device 3 is used to divide the specimens into multiple regions. At the bottom of the test device housing 1, a storage tank 16 is provided. Inside the test device housing 1, a partition plate 13 is fixedly connected. The storage tank 16 is divided into multiple regions by the partition plate 13. Inside the test device housing 1, a heating device 12 is provided. The heating device 12 is electrically connected to the control device 6 and is used to heat the inside of the storage tank 16. On the side of the test device housing 1, a detection device 24 is fixedly connected, which is used to detect the experimental results.

[0030] On the side of the test platform 15, a drainage plate 14 is fixedly connected. The drainage plate 14 has a structure with higher sides and a lower middle. At the center of the drainage plate 14, a water passing hole is provided, and the water passing hole communicates with the storage tank 16 provided at the bottom, which is more convenient for collecting the sprayed salt water. The salt water flows into the inside of the storage tank 16 through the water passing hole.

[0031] The storage tank 16 is arranged below the flushing nozzles 11. The number of partitions of the storage tank 16 is the same as the number of the flushing devices 4. At the bottom of the storage tank 16, a water pipe 17 is provided, and the water pipe 17 communicates with the control device 6. The heating device 12 is arranged on the side of the storage tank 16. A filter screen is provided at the water pipe 17 to prevent impurities from entering and blocking the inside.

[0032] On the bottom surface of the flushing device 4, a flushing nozzle 11 is fixedly connected, and the flushing nozzle 11 is used to spray salt water.

[0033] The partitioning device 3 includes a connecting plate 301. On the top of the connecting plate 301, a connecting block 302 is fixedly connected. Inside the connecting block 302, an air suction and exhaust device is provided. On the bottom of the connecting plate 301, a connecting groove 303 is provided. On the connecting groove 303, an air pipe 304 is provided, and the air suction and exhaust device communicates with the air pipe 304. When the connecting plate 301 contacts the specimen, the air suction and exhaust device provided inside the connecting block 302 starts to suck air inward from the air pipe 304 provided at the bottom of the connecting block 302, so that a negative pressure is generated at the place where the connecting groove 303 provided on the connecting plate 301 contacts the specimen, and the connecting plate 301 is tightly adsorbed on the specimen to prevent the mixing of salt water with different concentrations during the test and affect the test results.

[0034] The bottom of the connecting rod 18 is fixedly connected with a connecting shaft 19. The bottom of the connecting shaft 19 is fixedly connected with a connecting sleeve 20. The bottom of the connecting sleeve 20 is fixedly connected with a pressing block 22. The side of the connecting sleeve 20 is rotatably connected with a roller 21. A roller groove 23 is provided on the roller 21. A motor is arranged inside the connecting shaft 19, and the motor drives the roller 21 and the roller groove 22 to rotate.

[0035] A cover plate 9 is arranged on the top of the test device housing 1. The cover plate 9 is movably connected with the test device housing 1. A handle 8 is fixedly connected to the top of the cover plate 9. An observation window 2 is fixedly connected to the front side of the test device housing 1. Both the observation window 2 and the cover plate 9 are made of transparent materials.

[0036] The detection device 24 includes a detection unit, a preprocessing unit, a processing unit and a feedback unit.

[0037] Embodiment 2

[0038] Please refer to Figures 1 - 5 , a method for using a test device for evaluating the salt corrosion resistance of asphalt mixtures, the method comprising:

[0039] S1: Place the prepared specimen in a fixed mold, detect the surface of the specimen through the detection device 24, and fix the specimen by moving downward through the hydraulic device 5;

[0040] S2: Change the temperature of the brine, adjust and control the internal brine concentration, and at the same time adjust the rotation speeds of the roller 21 and the pressing block 22 and the water flow rate, and conduct multiple tests;

[0041] S3: Detect the surface of the specimen again, and evaluate the salt corrosion resistance of the specimen based on the detection results.

[0042] Before the test, the detection unit captures the deformed fringe pattern on the surface of the object by the four-step phase-shifting method. Four pictures are taken at different phases, and each picture corresponds to a different grating phase shift. For each group of phase-shifted images, the phase value at each pixel position is calculated to determine the height information of that point. The phase unwrapping algorithm is applied to remove the 2π discontinuity in the phase, and the phase information is converted into the actual height value. The two-dimensional phase diagram is converted into point cloud data in a three-dimensional coordinate system by using the principle of triangulation.

[0043] After the test, the detection unit captures the deformed fringe pattern on the surface of the object by the four-step phase-shifting method, takes four pictures at different phases, and converts the two-dimensional phase diagram into point cloud data in a three-dimensional coordinate system.

[0044] After obtaining the point cloud data at two time points, the analysis unit performs smoothing processing using non-local mean filtering, precisely aligns the data at different time points using the ICP algorithm, calculates the average height deviation and root mean square height of the surface using the roughness parameters defined by the ISO standard, and obtains the texture features of contrast, correlation, energy, and entropy by calculating the gray-level co-occurrence matrix (GLCM).

[0045] The mathematical expression of the gray-level co-occurrence matrix is as follows:

[0046] P(i,j|d,θ) = {(x,y)|f(x,y) = i, f(x + dx, y + dy) = j; x,y = 0,1,2,...,N - 1} where:

[0047] P(i,j|d,θ) represents the probability of the occurrence of pixel pairs with gray levels i and j at a distance d and direction θ;

[0048] f(x,y) represents the gray value of the point (x,y) in the image;

[0049] d is the relative distance expressed in the number of pixels;

[0050] θ is the direction angle, and generally four directions of 0°, 45°, 90°, and 135° are considered;

[0051] i,j = 0,1,2,...,L - 1, where L is the number of gray levels of the image;

[0052] (x,y) are the pixel coordinates in the image.

[0053] Select an appropriate voxel size according to the required analysis accuracy. During the detection, the test piece is split into four hundred to nine hundred grids, and the voxel states in the two scanning results before and after are compared. For each voxel position, check whether its state has changed at two time points. For example, if a certain voxel is "filled" in the initial state and becomes "empty" in the subsequent scan, it indicates that material loss has occurred in this area. Based on the above differences, the total volume loss can be calculated. Count the number of voxels that change from "filled" to "empty" and multiply by the volume of a single voxel to obtain the total volume loss, so as to quickly determine the surface erosion state of the asphalt mixture during the test.

[0054] In the study of the salt erosion resistance performance of asphalt mixtures, this device can well simulate the performance of asphalt mixtures under the simultaneous action of vehicle wheels and salt erosion during road use during the process of repeatedly eroding the test piece with salt water. Combining the physical test results and analysis results, comprehensively evaluate the durability and erosion resistance of asphalt mixtures, and establish a regression model or survival analysis model to predict the service life of the material.

[0055] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A test device for evaluating the salt corrosion resistance of asphalt mixture, comprising a test device housing (1), characterized in that: A test platform (15) is fixedly connected to the inside of the test device housing (1), a fixed plate (10) is fixedly connected to the top of the test platform (15), the inside of the fixed plate (10) is used to store asphalt mixture test pieces, a control device (6) is fixedly connected to the side of the test device housing (1), a support device (7) is fixedly connected to the top of the control device (6), a hydraulic device (5) is movably connected to the bottom of the support device (7), a connecting rod (18) is fixedly connected to the bottom of the hydraulic device (5), a flushing device (4) and a partition device (3) are fixedly connected to the connecting rod (18), and the flushing device (4) is used to flush the hydraulic device (5) and the partition device (3). The test piece is flushed, the partition device (3) is used to divide the test piece into multiple areas, a storage box (16) is provided at the bottom of the test device shell (1), a partition plate (13) is fixedly connected to the inside of the test device shell (1), and the storage box (16) is divided into multiple areas by the partition plate (13), a heating device (12) is provided inside the test device shell (1), the heating device (12) is electrically connected to the control device (6), and the heating device (12) is used to heat the inside of the storage box (16), and a detection device (24) is fixedly connected to the side of the test device shell (1) for detecting the experimental results.

2. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 1, characterized in that: A drainage plate (14) is fixedly connected to the side of the test platform (15), and the drainage plate (14) is a structure with high sides and a low middle. A water hole is opened at the center of the drainage plate (14), and the water hole is connected to a storage box (16) arranged at the bottom.

3. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 2, characterized in that: The storage box (16) is arranged below the flushing nozzle (11); the number of partitions of the storage box (16) is the same as the number of the flushing device (4); a water flow pipe (17) is provided at the bottom of the storage box (16); the water flow pipe (17) is communicated with the control device (6); the heating device (12) is arranged on the side of the storage box (16); and a filter is provided at the water flow pipe (17).

4. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 3, characterized in that: A flushing nozzle (11) is fixedly connected to the bottom surface of the flushing device (4).

5. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 4, characterized in that: The partition device (3) comprises a connecting plate (301), the top of the connecting plate (301) is fixedly connected to a connecting block (302), an exhaust and intake device is arranged inside the connecting block (302), a connecting groove (303) is provided on the bottom of the connecting plate (301), and a ventilation pipe (304) is provided on the connecting groove (303).

6. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 5, characterized in that: The bottom of the connecting rod (18) is fixedly connected to a connecting shaft (19), the bottom of the connecting shaft (19) is fixedly connected to a connecting sleeve (20), the bottom of the connecting sleeve (20) is fixedly connected to a pressing block (22), the side of the connecting sleeve (20) is rotatably connected to a roller (21), the roller (21) is provided with a roller groove (23), and a motor is arranged inside the connecting shaft (19), and the motor drives the roller (21) and the roller groove (22) to rotate.

7. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 6, characterized in that: A cover plate (9) is provided on the top of the test device housing (1), the cover plate (9) is movably connected to the test device housing (1), a handle (8) is fixedly connected to the top of the cover plate (9), and an observation window (2) is fixedly connected to the front side of the test device housing (1).

8. A test device for evaluating the salt corrosion resistance of asphalt mixture according to claim 7, characterized in that: The detection device (24) comprises a detection unit, a preprocessing unit, a processing unit and a feedback unit.

9. A method for using a test device for evaluating the anti-salt corrosion performance of asphalt mixtures, wherein the test device for evaluating the anti-salt corrosion performance of asphalt mixtures according to claim 8 is characterized in that: The method includes: S1: placing the prepared test piece in a fixed mold, inspecting the surface of the test piece through a detection device (24), and fixing the test piece by moving downwards through a hydraulic device (5); S2: changing the temperature of the brine inside the device, adjusting and controlling the concentration of the brine inside, and adjusting the rotation speed of the roller (21) and the pressing block (22) as well as the water flow rate, and performing multiple tests; S3: Test the surface of the specimen again and evaluate the salt corrosion resistance of the specimen based on the test results.

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