Water permeability detection device and method for detecting water permeability of asphalt pavement

Abstract

The invention relates to the technical field of engineering material water seepage performance testing, in particular to a water seepage performance detection device and a method for detecting the water seepage performance of an asphalt pavement. The water seepage performance detection device comprises a rack, a rectangular cylinder barrel and a test piece cavity which are communicated with each other are sequentially fixed to the rack from top to bottom, and a piston is in sliding fit in the rectangular cylinder barrel; a power driving device for driving the piston to move up and down is arranged on the rack; an air inlet pipe is fixed to the rectangular cylinder barrel, in the reciprocating motion process of the piston, external air is periodically sucked into the rectangular cylinder barrel through the air inlet pipe, and dynamic pressurization is formed on liquid in the rectangular cylinder barrel; according to the invention, the vertical dynamic pressure generated by the piston is coupled with the horizontal asymmetric surge excited by the plug flow plate, and the dynamic composite hydraulic load highly similar to the actual pavement can be reproduced in the surface and internal pores of the test piece, so that the dynamic water damage resistance of the asphalt pavement can be evaluated more truly and accurately.

Description

Technical Field

[0001] This invention relates to the field of engineering material permeability testing technology, specifically a permeability testing device and a method for testing the permeability of asphalt pavement. Background Technology

[0002] As a typical engineering material composite, the permeability of asphalt pavement is one of the key indicators for evaluating the durability and resistance to water damage of the engineering material. At present, the conventional method for testing permeability generally adopts the hydrostatic head permeability meter. Its basic operation is to fill the sealed test chamber with liquid, which relies on the liquid to naturally seep into the pavement under the action of fixed hydrostatic pressure. By observing and recording the height and time of the liquid level drop, the permeability coefficient is calculated.

[0003] However, the above methods have obvious limitations: in actual use environments, the water on the road surface is not in a static state, but is subjected to the rolling, squeezing and shearing action of vehicle tires, forming dynamic and instantaneous pressure impacts and water flow disturbances. This dynamic hydraulic load will accelerate the intrusion and migration of water into the interior of the asphalt mixture, thereby inducing water damage phenomena such as spalling and loosening. Traditional static water seepage test methods cannot simulate this real stress state, resulting in a weak correlation between the test results and the actual water damage resistance performance of the road surface under actual traffic loads, making it difficult to accurately reflect the water seepage behavior of the road surface under dynamic hydraulic coupling.

[0004] Therefore, there is an urgent need for a permeability testing device and method that can simulate the dynamic pressure and flow state of rainwater during actual road use, so as to more realistically and effectively evaluate the permeability and long-term service performance of asphalt pavement. To this end, we provide a permeability testing device and a method for testing the permeability of asphalt pavement to solve the above-mentioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a permeability testing device and a method for testing the permeability of asphalt pavement. This device and method can simulate the dynamic pressure and flow state of rainwater during actual pavement use, so as to more realistically and effectively evaluate the permeability and long-term service performance of asphalt pavement, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A water permeability testing device includes a frame, on which a rectangular cylinder and a specimen cavity are fixed sequentially from top to bottom. A piston is slidably fitted inside the rectangular cylinder, and a power drive device is provided on the frame to drive the piston to move up and down. An air intake pipe is fixed on the rectangular cylinder. During the reciprocating motion of the piston, external gas is periodically drawn into the rectangular cylinder through the air intake pipe, which dynamically pressurizes the liquid inside the rectangular cylinder. The two inner walls of the rectangular cylinder are slidably mounted on each side. The two pusher plates are connected to the piston through a linkage mechanism. When the piston moves up and down, it will drive the two pusher plates to move relative to each other or towards each other, thereby causing the liquid inside the rectangular cylinder to form a surge.

[0007] As described above, a water seepage performance testing device is provided with multiple mounting holes spaced at equal angles along the circumference of the frame. Anchor bolts are installed in the mounting holes, and the frame is fixed to the ground by the anchor bolts.

[0008] A water permeability testing device as described above: a liquid injection pipe for injecting liquid into the rectangular cylinder is fixedly installed on the rectangular cylinder, and a valve is fixedly installed on the liquid injection pipe.

[0009] A water permeability testing device as described above: the power drive device includes a hydraulic cylinder fixed on the frame, and a piston rod is provided at the output end of the hydraulic cylinder, and the piston rod is fixed to the piston.

[0010] As described above, a water seepage performance testing device is provided with a one-way valve installed on the air inlet pipe. The one-way valve only allows external gas to enter the rectangular cylinder through the air inlet pipe, while the gas inside the rectangular cylinder cannot leak out through the air inlet pipe.

[0011] A water seepage performance testing device as described above: the linkage mechanism includes a support base fixed on a rectangular cylinder, a bidirectional lead screw rotatably mounted on the support base, a drive block fixed on the push plate, the bidirectional lead screw passing through the drive block, the push plate, and the rectangular cylinder, and the drive block and the bidirectional lead screw being threadedly engaged; a limiting component for the movement of the push plate is provided on the support base; the bidirectional lead screw and the piston rod are engaged through a transmission mechanism, and the piston rod moving up and down will drive the bidirectional lead screw to rotate clockwise and counterclockwise.

[0012] As described above, a water seepage performance testing device includes a limiting component comprising two guide rods symmetrically distributed on both sides of a bidirectional lead screw and fixed on a support base. The guide rods pass through the drive block, the pusher plate, and the rectangular cylinder.

[0013] A water permeability testing device as described above: the transmission mechanism includes a mounting base fixed to the side wall of a rectangular cylinder, a transmission shaft sleeve rotatably mounted on the mounting base, the transmission shaft sleeve and a double-acting lead screw being engaged through a bevel gear mechanism, the rotation of the transmission shaft sleeve causing the double-acting lead screw to rotate synchronously, a lifting rod being movably inserted into the transmission shaft sleeve, the lifting rod being fixedly connected to a piston rod through a connecting rod, the lifting rod and the transmission shaft sleeve being engaged through a grooving mechanism, the lifting rod moving up and down within the transmission shaft sleeve causing the transmission shaft sleeve to rotate clockwise and counterclockwise.

[0014] As described above, a water permeability testing device includes a bevel gear mechanism comprising a driving bevel gear fixed on a transmission shaft sleeve and a driven bevel gear fixed on a bidirectional lead screw, wherein the driving bevel gear meshes with the driven bevel gear. The grooving mechanism includes a spiral groove formed on the lifting rod and balls embedded and engaged in the inner wall of the transmission shaft sleeve. The balls are movably engaged in the spiral groove and can roll along the groove.

[0015] A method for testing the permeability performance of asphalt pavement using the aforementioned permeability testing device includes the following steps: S1. Securely install the frame onto the asphalt pavement to be tested or the specimen support platform using the anchor bolts at its bottom, so that the asphalt pavement sample to be tested completely fills the inside of the specimen cavity and ensures that the bottom opening of the specimen cavity is in contact with the pavement or the specimen support platform. S2. Inject the test liquid into the rectangular cylinder through the injection pipe until the predetermined initial liquid level is reached; S3. Start the power drive device and drive the piston to move back and forth in the rectangular cylinder according to the preset pattern. During this process, external gas is periodically drawn in through the air intake pipe and dynamically pressurizes the liquid in the rectangular cylinder to simulate the pressure impact on the road surface. At the same time, the linkage mechanism drives the two pusher plates to move relative to or towards each other in the rectangular cylinder, thereby creating a surging effect in the liquid to simulate the combined effect of dynamic water flow on the road surface. S4. Within the preset test duration, the volume of liquid that seeps into the asphalt pavement from the bottom of the specimen cavity is measured and the corresponding test time is recorded. The permeability parameters of the asphalt pavement under dynamic water pressure and surge conditions are obtained by calculation.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention drives the piston to reciprocate in the rectangular cylinder through the driving device, and uses the linkage mechanism to synchronously convert the vertical reciprocating motion of the piston into the horizontal reciprocating motion of the pusher plates on both sides of the rectangular cylinder. This allows the piston to compress the gas drawn in through the air intake pipe and apply dynamic pulse pressure to the liquid in the rectangular cylinder, simulating the instantaneous vertical impact and squeezing of the vehicle tires on the road surface rainwater. The movement of the pusher plates can also generate horizontal surging waves and shear flow in the liquid. Thus, the dynamic and composite hydraulic load environment of the road surface water under actual driving load is reproduced, overcoming the fundamental limitation of the traditional static head infiltration instrument that can only simulate static water accumulation, and significantly improving the authenticity of the test conditions. (2) This invention uses a set of purely mechanical linkage and transmission mechanisms to realize the up and down movement of the piston driven by a single power source hydraulic cylinder. After transmission, it ultimately controls the two actions of vertical pressurization and horizontal surge generation in the rectangular cylinder at the same time. The up and down movement of the piston rod is converted into the forward and reverse rotation of the transmission shaft sleeve through the spiral groove and ball on the lifting rod that is fixedly connected to it. Then, the bidirectional screw is driven to rotate through the bevel gear pair. Finally, the push plate is driven to move horizontally through the threaded connection. This design is compact and reliable. It does not require a complex electrical control or hydraulic synchronization system, which reduces the complexity of the device and the manufacturing cost. At the same time, it ensures the strict synchronization of the two dynamic loads. By changing the operating power of the hydraulic cylinder, the impact frequency, pressure amplitude and surge intensity can be easily adjusted, which enhances the practicality of the device and the adaptability of the test scenario. (3) The detection method provided by the present invention measures the water permeability of the road surface by using the above-mentioned device to form dynamic pressurization and surging waves in a rectangular cylinder. It can reveal the potential water permeability defects of asphalt mixture under real dynamic load hydraulic action more sensitively and earlier. The dynamic water permeability parameters obtained by this method are more correlated with the risk of water damage to the road surface in actual traffic environment. It can provide a more scientific and accurate evaluation basis for asphalt pavement material design, mix ratio optimization and construction quality control, and help to improve the long-term durability and service performance of the road surface from the source. Attached Figure Description

[0017] Figure 1 A schematic diagram of the overall structure of a water permeability testing device from a first-view perspective; Figure 2 A schematic diagram of the overall structure of a water permeability testing device from a second perspective; Figure 3 A schematic diagram of the overall structure of a water permeability testing device from a third-view perspective; Figure 4 for Figure 2 A schematic diagram of the decomposed partial structure; Figure 5 for Figure 4A schematic diagram of the structure after partial sectional view of the rectangular cylinder; Figure 6 for Figure 5 A schematic diagram of the decomposed partial structure; Figure 7 for Figure 6 A schematic diagram of the decomposed partial structure; Figure 8 for Figure 7 A schematic diagram of the decomposed partial structure; Figure 9 for Figure 7 A schematic diagram of the decomposed partial structure; Figure 10 for Figure 9 A schematic diagram of the decomposed part of the structure.

[0018] In the diagram: 1. Frame; 2. Anchor bolts; 3. Rectangular cylinder; 4. Specimen cavity; 5. Injection pipe; 6. Piston; 7. Hydraulic cylinder; 8. Piston rod; 9. Air inlet pipe; 10. Pusher plate; 11. Support base; 12. Double-acting lead screw; 13. Drive block; 14. Guide rod; 15. Threaded hole; 16. Guide hole; 17. Mounting base; 18. Transmission shaft sleeve; 19. Lifting rod; 20. Connecting rod; 21. Spiral groove; 22. Ball bearing; 23. Driving bevel gear; 24. Driven bevel gear. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Please see Figure 1-10 As an embodiment of the present invention, a water permeability testing device includes a frame 1, on which a rectangular cylinder 3 and a specimen cavity 4 are fixed from top to bottom and communicate with each other. A piston 6 is slidably fitted inside the rectangular cylinder 3. A power drive device for driving the piston 6 to move up and down is provided on the frame 1. An intake pipe 9 is fixed on the rectangular cylinder 3. During the reciprocating movement of the piston 6, external gas is periodically drawn into the rectangular cylinder 3 through the intake pipe 9, and dynamic pressure is generated on the liquid inside the rectangular cylinder 3. Pusher plates 10 are slidably installed on the inner walls of both sides of the rectangular cylinder 3. The two pusher plates 10 are connected to the piston 6 through a linkage mechanism. When the piston 6 moves up and down, it will drive the two pusher plates 10 to move relative to each other or towards each other, thereby causing the liquid inside the rectangular cylinder 3 to form a surge.

[0021] In this embodiment, during use, the frame 1 is first securely installed on the asphalt pavement to be tested or on the specimen support platform, ensuring that the asphalt pavement specimen to be tested is filled inside the specimen cavity 4. The test liquid is injected into the device through the injection pipe 5 to the predetermined initial liquid level. The power drive device is then activated, driving the piston 6 to begin reciprocating up and down in a preset pattern within the rectangular cylinder 3. When the piston 6 moves upward, a negative pressure is created inside the rectangular cylinder 3. At this time, external gas is drawn into the rectangular cylinder 3 through the air inlet pipe 9. Subsequently, when the piston 6 moves downward, it compresses this portion of gas within the rectangular cylinder 3, thereby applying a periodic, dynamically changing pressure to the liquid on the surface of the asphalt pavement in the specimen cavity 4 connected below. This process simulates the transient vertical impact and compression experienced by the pavement water film. Simultaneously, the reciprocating motion of piston 6 is converted into the horizontal reciprocating movement of two pusher plates 10 within the rectangular cylinder 3 via a linkage mechanism. This periodic horizontal movement of the pusher plates 10 generates surging waves and horizontal shear flow in the liquid within the rectangular cylinder 3, simulating the pushing and agitating effect of dynamic water flow on the road surface. Through the synchronous coupling effect of the vertical pressurization of piston 6 and the horizontal surging waves of pusher plates 10, the device reproduces a dynamic, composite hydraulic load highly similar to the actual road surface environment on the surface of the specimen and in its internal pores. Under these conditions, by measuring the volume of liquid that seeps into the specimen from the bottom of the specimen cavity 4 within a specified time and recording the time, the permeability parameters of the asphalt mixture under a more realistic stress state can be calculated, thereby providing a more accurate assessment of its resistance to dynamic water damage.

[0022] Furthermore, the rectangular cylinder 3 is made of transparent plastic or glass, and its surface is marked with scale lines for easy and intuitive viewing of the internal liquid level.

[0023] As a further embodiment of the present invention, the frame 1 is provided with a plurality of mounting holes at equal angles along the circumference, and anchor bolts 2 are installed in the mounting holes, and the frame 1 is fixed to the ground by the anchor bolts 2.

[0024] In this embodiment, by setting multiple mounting holes and anchor bolts 2, the device can be firmly anchored to the ground or the specimen support platform, effectively preventing the device from shaking or shifting due to dynamic loads during the test, and ensuring the stability of the test and the repeatability of the results.

[0025] As a further embodiment of the present invention, a liquid injection pipe 5 for injecting liquid into the rectangular cylinder 3 is fixedly installed on the rectangular cylinder 3, and a valve is fixedly installed on the liquid injection pipe 5.

[0026] In this embodiment, the injection tube 5 is used to inject the test liquid into the rectangular cylinder 3. The valve constitutes the liquid injection and closing control path, which facilitates the convenient and controllable addition of the test liquid into the device before the test, and the valve is closed after the liquid is injected to form a closed test environment inside the rectangular cylinder 3.

[0027] As a further embodiment of the present invention, the power drive device includes a hydraulic cylinder 7 fixed on the frame 1, and a piston rod 8 is provided at the output end of the hydraulic cylinder 7, with the piston rod 8 fixed to the piston 6.

[0028] In this embodiment, the power drive device is specifically composed of a hydraulic cylinder 7 and a piston rod 8 at its output end. The hydraulic cylinder 7 serves as a power source, directly driving the piston 6 to perform precise up-and-down reciprocating linear motion through the piston rod 8, providing controllable and stable core motion input for the entire test.

[0029] As a further embodiment of the present invention, a one-way valve is installed on the intake pipe 9. The one-way valve only allows external gas to enter the rectangular cylinder 3 through the intake pipe 9, while the gas inside the rectangular cylinder 3 cannot leak out through the intake pipe 9.

[0030] In this embodiment, the one-way valve installed on the intake pipe 9 ensures the one-way flow of gas. When the piston 6 moves upward to generate negative pressure, external air can be drawn into the rectangular cylinder 3. When the piston 6 moves downward to compress the gas, the high-pressure gas cannot escape from here and can only act on the liquid, thereby effectively converting the mechanical energy of the piston 6 into periodic gas pressure pulses on the liquid.

[0031] As a further embodiment of the present invention, the linkage mechanism includes a support base 11 fixed on a rectangular cylinder 3, a bidirectional lead screw 12 rotatably mounted on the support base 11, a drive block 13 fixed on the push plate 10, the bidirectional lead screw 12 passing through the drive block 13, the push plate 10, and the rectangular cylinder 3, and the drive block 13 and the bidirectional lead screw 12 are threadedly engaged. The support base 11 is provided with a limiting component when the push plate 10 moves. The bidirectional lead screw 12 and the piston rod 8 are engaged through a transmission mechanism. When the piston rod 8 moves up and down, it will drive the bidirectional lead screw 12 to rotate clockwise and counterclockwise.

[0032] In this embodiment, the drive block 13 has a threaded hole 15, and the drive block 13 is threadedly connected to the bidirectional lead screw 12 through the threaded hole 15. The core of the linkage mechanism is the threaded pair between the bidirectional lead screw 12 and the drive block 13. When the bidirectional lead screw 12 rotates in both directions under the drive of the transmission mechanism, since the drive block 13 is fixed to the pusher plate 10, and the movement of the pusher plate 10 is constrained by the limiting component to only be horizontal, the rotational motion of the bidirectional lead screw 12 is precisely converted into the horizontal reciprocating linear motion of the two pusher plates 10. In particular, The left and right threads of the bidirectional lead screw 12 are designed with different specifications, i.e., different leads, so that the two pusher plates 10 have different moving speeds. Through this design, the right pusher plate 10 moves faster than the left, or vice versa. The speed difference effectively avoids the situation where the liquid flow disturbance cancels each other out due to the synchronous symmetrical movement of the two pusher plates. This allows for the continuous generation of asymmetrical agitation and shearing in the liquid in the rectangular cylinder 3, significantly enhancing the generation effect of surging waves and making the simulation of dynamic hydraulic loads more realistic and intense.

[0033] As a further embodiment of the present invention, the limiting component includes two guide rods 14 symmetrically distributed on both sides of the bidirectional lead screw 12 and fixed on the support base 11. The guide rods 14 pass through the drive block 13, the pusher plate 10, and the rectangular cylinder 3.

[0034] In this embodiment, the limiting component is composed of a guide rod 14. The drive block 13 has a threaded hole 15 with an inner diameter that matches the outer diameter of the guide rod 14. The guide rod 14 is inserted into the guide hole 16. The guide rod 14 passes through the rectangular cylinder 3, the pusher plate 10, and the drive block 13 in sequence, providing precise sliding guidance for the movement of the pusher plate 10 and the drive block 13. It strictly limits the movement to the axial direction of the guide rod 14 and prevents the pusher plate 10 from rotating with the bidirectional lead screw 12, thereby ensuring the accuracy and reliability of the pusher plate 10 when it moves.

[0035] As a further embodiment of the present invention, the transmission mechanism includes a mounting base 17 fixed to the side wall of the rectangular cylinder 3. A transmission shaft sleeve 18 is rotatably mounted on the mounting base 17. The transmission shaft sleeve 18 and the double-acting lead screw 12 are connected through a bevel gear mechanism. When the transmission shaft sleeve 18 rotates, it will drive the double-acting lead screw 12 to rotate synchronously. A lifting rod 19 is movably inserted into the transmission shaft sleeve 18. The lifting rod 19 is fixedly connected to the piston rod 8 through a connecting rod 20. The lifting rod 19 and the transmission shaft sleeve 18 are connected through a grooving mechanism. When the lifting rod 19 moves up and down in the transmission shaft sleeve 18, it will drive the transmission shaft sleeve 18 to rotate clockwise and counterclockwise.

[0036] In this embodiment, the transmission mechanism can convert the vertical reciprocating motion of the piston rod 8 into the forward and reverse rotational motion of the bidirectional lead screw 12. The lifting rod 19 moves up and down with the piston rod 8, and interacts with the transmission shaft sleeve 18 through the rolling groove mechanism on it, forcing the transmission shaft sleeve 18 to reciprocate. The rotational motion of the transmission shaft sleeve 18 then changes the transmission direction through the bevel gear mechanism, and finally drives the bidirectional lead screw 12 to rotate synchronously, so that when the piston rod 8 moves up and down, it can drive the bidirectional lead screw 12 to rotate clockwise and counterclockwise.

[0037] As a further embodiment of the present invention, the bevel gear mechanism includes a driving bevel gear 23 fixed on the transmission shaft sleeve 18 and a driven bevel gear 24 fixed on the bidirectional lead screw 12, wherein the driving bevel gear 23 meshes with the driven bevel gear 24. The grooving mechanism includes a spiral groove 21 formed on the lifting rod 19 and balls 22 embedded and engaged in the inner wall of the transmission shaft sleeve 18. The balls 22 are movably engaged in the spiral groove 21 and can roll along the groove where the spiral groove 21 is located.

[0038] In this embodiment, the bevel gear mechanism consists of a driving bevel gear 23 and a driven bevel gear 24 meshing with each other. The bevel gear mechanism can convert the rotation of the transmission shaft sleeve 18 around the vertical axis into the rotation of the bidirectional lead screw 12 around the horizontal axis. The grooving mechanism is specifically composed of the spiral groove 21 on the lifting rod 19 and the ball bearings 22 on the inner wall of the transmission shaft sleeve 18. When the lifting rod 19 moves up and down, the ball bearings 22 roll along the spiral groove 21, thereby converting the linear motion of the lifting rod 19 into the rotational motion of the transmission shaft sleeve 18. The rotation angle, speed and direction of the transmission shaft sleeve 18 can be adjusted by changing the specific shape of the spiral groove 21 on the lifting rod 19.

[0039] The working principle of this invention is as follows: The hydraulic cylinder 7 is the core drive source. Its output end drives the piston 6 to perform precise up-and-down reciprocating motion within the rectangular cylinder 3 via the piston rod 8. When the piston 6 moves upward, a negative pressure is created within the rectangular cylinder 3. At this time, the one-way valve in the air intake pipe 9 mounted on the cavity opens, drawing external air into the cavity. Subsequently, when the piston 6 moves downward, the air within the rectangular cylinder 3 is compressed, thereby applying a periodic, dynamically changing pressure pulse to the liquid within the rectangular cylinder 3. This process continues in a cycle, simulating the instantaneous pressure pulse experienced by the water film on a real road surface. The vertical impact and compression action; in addition, the reciprocating motion of piston 6 is synchronously converted into horizontal fluid flow disturbance through a mechanical linkage system. When piston 6 moves up and down, it drives piston rod 8 to move up and down linearly, which first drives the lifting rod 19 fixed to it to move synchronously. The spiral groove 21 opened on the surface of lifting rod 19 and the ball 22 embedded in the inner wall of transmission shaft sleeve 18 form a grooving mechanism. This mechanism converts the vertical linear motion of lifting rod 19 into the reciprocating rotational motion of transmission shaft sleeve 18. The rotation of transmission shaft sleeve 18 is achieved through a bevel gear mechanism composed of driving bevel gear 23 and driven bevel gear 24. The transmission direction is changed, driving the horizontally positioned bidirectional lead screw 12 to rotate alternately in the forward and reverse directions. The left and right threads of the bidirectional lead screw 12 are set with different leads. When the bidirectional lead screw 12 rotates, through the threaded engagement with the left and right drive blocks 13 and under the limiting of the guide rod 14, the rotational motion is converted into the horizontal reciprocating linear motion of two pusher plates 10 installed on the inner walls of both sides of the rectangular cylinder 3. Due to the different thread leads, the motion speed of the two pusher plates 10 is different, so they do not push synchronously and symmetrically in the liquid, but generate asymmetrical shear force and flow. The velocity field effectively avoids the mutual cancellation of symmetrical disturbances, thereby continuously and efficiently generating strong, asymmetrical surges and horizontal shear flows in the liquid in the specimen cavity 4. This realistically simulates the lateral pushing, scouring, and agitation effects of dynamic water flow in the road surface voids. Ultimately, the vertical dynamic pulsating pressure on the liquid in the rectangular cylinder 3 and the horizontal asymmetrical surges and shear flows of the liquid are synchronously coupled in time and space, jointly applying a highly simulated dynamic composite hydraulic load generated under actual road conditions to the surface of the asphalt mixture specimen placed in the specimen cavity 4 and its internal pore network.

[0040] The above embodiments are exemplary and not restrictive. Therefore, any technical solutions that can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention are included within the scope of the present invention.

Claims

1. A permeability testing device, comprising a frame (1), characterized in that, The frame (1) is fixed with a rectangular cylinder (3) and a specimen cavity (4) connected to each other from top to bottom. A piston (6) is slidably fitted inside the rectangular cylinder (3). The frame (1) is provided with a power drive device to drive the piston (6) to move up and down. An air inlet pipe (9) is fixed on the rectangular cylinder (3). During the reciprocating motion of the piston (6), external gas is periodically drawn into the rectangular cylinder (3) through the air inlet pipe (9), and dynamic pressure is generated on the liquid in the rectangular cylinder (3). The rectangular cylinder (3) has two pusher plates (10) slidably installed on the inner walls of its two sides. The two pusher plates (10) are connected to the piston (6) through a linkage mechanism. When the piston (6) moves up and down, it will drive the two pusher plates (10) to move relative to each other or towards each other, thereby causing the liquid inside the rectangular cylinder (3) to form a surge.

2. The water permeability testing device according to claim 1, characterized in that, The frame (1) has multiple mounting holes spaced at equal angles along its circumference. Anchor bolts (2) are installed in the mounting holes, and the frame (1) is fixed to the ground by the anchor bolts (2).

3. The water permeability testing device according to claim 1, characterized in that, A liquid injection pipe (5) for injecting liquid into the rectangular cylinder (3) is fixedly installed on the rectangular cylinder (3), and a valve is fixedly installed on the liquid injection pipe (5).

4. The water permeability testing device according to claim 1, characterized in that, The power drive device includes a hydraulic cylinder (7) fixed on the frame (1), and a piston rod (8) is provided at the output end of the hydraulic cylinder (7), and the piston rod (8) is fixed to the piston (6).

5. The water permeability testing device according to claim 1, characterized in that, A one-way valve is installed on the intake pipe (9). The one-way valve only allows external gas to enter the rectangular cylinder (3) through the intake pipe (9), while the gas inside the rectangular cylinder (3) cannot leak out through the intake pipe (9).

6. The water permeability testing device according to claim 4, characterized in that, The linkage mechanism includes a support base (11) fixed on a rectangular cylinder (3), a bidirectional lead screw (12) rotatably mounted on the support base (11), a drive block (13) fixed on the push plate (10), the bidirectional lead screw (12) passing through the drive block (13), the push plate (10) and the rectangular cylinder (3), and the drive block (13) and the bidirectional lead screw (12) are threaded together. The support base (11) is provided with a limiting component when the push plate (10) moves. The bidirectional lead screw (12) and the piston rod (8) are connected through a transmission mechanism. When the piston rod (8) moves up and down, it will drive the bidirectional lead screw (12) to rotate clockwise and counterclockwise.

7. The water permeability testing device according to claim 6, characterized in that, The limiting component includes two guide rods (14) fixed on the support base (11) and symmetrically distributed on both sides of the bidirectional lead screw (12). The guide rods (14) pass through the drive block (13), the pusher plate (10), and the rectangular cylinder (3).

8. The water permeability testing device according to claim 6, characterized in that, The transmission mechanism includes a mounting base (17) fixed to the side wall of a rectangular cylinder (3). A transmission shaft sleeve (18) is rotatably mounted on the mounting base (17). The transmission shaft sleeve (18) and the double-acting lead screw (12) are connected through a bevel gear mechanism. When the transmission shaft sleeve (18) rotates, it will drive the double-acting lead screw (12) to rotate synchronously. A lifting rod (19) is movably inserted into the transmission shaft sleeve (18). The lifting rod (19) is fixedly connected to the piston rod (8) through a connecting rod (20). The lifting rod (19) and the transmission shaft sleeve (18) are connected through a grooving mechanism. When the lifting rod (19) moves up and down inside the transmission shaft sleeve (18), it will drive the transmission shaft sleeve (18) to rotate clockwise and counterclockwise.

9. The water permeability testing device according to claim 8, characterized in that, The bevel gear mechanism includes a driving bevel gear (23) fixed on a transmission shaft sleeve (18) and a driven bevel gear (24) fixed on a double-acting lead screw (12), wherein the driving bevel gear (23) meshes with the driven bevel gear (24); The grooving mechanism includes a spiral groove (21) formed on the lifting rod (19) and a ball (22) embedded and engaged in the inner wall of the transmission shaft sleeve (18). The ball (22) is movably engaged in the spiral groove (21) and can roll along the groove where the spiral groove (21) is located.

10. A method for testing the permeability performance of asphalt pavement using the permeability testing device as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Securely install the frame (1) onto the asphalt pavement to be tested or the specimen support platform using the anchor bolts (2) at its bottom, so that the asphalt pavement specimen to be tested is completely filled inside the specimen cavity (4) and the bottom opening of the specimen cavity (4) is in contact with the pavement or the specimen support platform. S2. Inject the test liquid into the rectangular cylinder (3) through the injection pipe (5) to the predetermined initial liquid level; S3. Start the power drive device and drive the piston (6) to move back and forth in the rectangular cylinder (3) according to the preset pattern. During this process, external gas is periodically drawn in through the air intake pipe (9) and the liquid in the rectangular cylinder (3) is dynamically pressurized to simulate the pressure impact on the road surface. At the same time, the two pusher plates (10) are driven to move relative to each other or towards each other in the rectangular cylinder (3) through the linkage mechanism, thereby forming a surging effect in the liquid to simulate the comprehensive effect of dynamic water flow on the road surface. S4. Within the preset test duration, the volume of liquid that seeps into the asphalt pavement from the bottom of the specimen cavity (4) is measured and the corresponding test time is recorded. The permeability performance parameters of the asphalt pavement under dynamic water pressure and surging wave conditions are obtained by calculation.

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