Testing device for simulating cement concrete pavement slab void damage

Abstract

The utility model discloses a test device for simulating a cement concrete pavement slab void disease, the device comprises a pavement slab model, a load model, a rainfall model and a monitoring device, the load model is arranged on a road model and can move back and forth on the road model; the rainfall model is used for rainfall above the road model; the monitoring equipment comprises a computer as well as a pressure sensor, a flow velocity sensor and a camera which are in communication connection with the computer, and the pressure sensor, the flow velocity sensor and the camera are all arranged in the pavement slab model; the device is used for simulating the formation and development process of the void under different working conditions, and test results can provide a basis for preventing the void of the concrete pavement, prolonging the service life of the pavement and guaranteeing the service performance of the pavement.

Description

Technical Field

[0001] This utility model relates to the field of research on void defects, and in particular to an experimental device for simulating void defects in cement concrete pavement slabs. Background Technology

[0002] Due to its advantages such as long service life, mature design and construction methods, and readily available materials, cement concrete pavement dominates the airport pavement market in my country. According to incomplete statistics, nearly 90% of the pavement types in China's existing airports are cement concrete pavements. Voiding is a common defect in airport cement concrete pavements. Statistics show that approximately 70% of airport pavements in my country have a voiding rate greater than 30%, and approximately 30% have a voiding rate greater than 60% (considered severe voiding). Voiding significantly increases pavement load stress, with a maximum increase of nearly 70% under adverse conditions. This significantly reduces the pavement's structural load-bearing capacity, shortens its service life, and increases the likelihood of structural defects (slab breakage, cracks).

[0003] Existing technologies related to airport pavement defects, such as the airport runway defect detection and early warning system in patent CN116242833A, achieve real-time detection and removal of airport runway defects, and provide functions for discovering, classifying, reporting, and issuing early warnings of potential threats to airport runway surfaces. It also proposes an efficient airport runway defect detection algorithm design to meet the requirements of real-time detection. In-depth research into the formation mechanism of voids in cement concrete pavements, especially revealing the aggravating effect of water accumulation on void defects, has important guiding significance for preventing and repairing voids, extending pavement service life, and ensuring pavement performance. Model testing is an important approach to studying the formation mechanism of voids in cement concrete pavements, but currently, complete experimental methods are lacking. Utility Model Content

[0004] The purpose of this utility model is to provide an experimental device for simulating voids in cement concrete pavement slabs, thus solving the problem of the lack of experimental models in the existing technology for studying the formation mechanism of voids in cement concrete pavement slabs.

[0005] This invention is achieved by providing an experimental device for simulating voids in cement concrete pavement slabs, comprising a pavement slab model, a load model, a rainfall model, and monitoring equipment.

[0006] The load model is placed on the road model and can move back and forth on the road model;

[0007] The rainfall model is used to generate rainfall over the road model;

[0008] The monitoring equipment includes a computer and pressure sensors, flow sensors, and cameras that are communicatively connected to the computer. The pressure sensors, flow sensors, and cameras are all placed inside the pavement panel model.

[0009] Practice shows that temperature changes causing concrete slab warping and the minute plastic deformation of the base layer under aircraft loads can lead to initial voids at the bottom of the slab. Subsequently, rainfall flows into the base layer and voided areas along the road joints. Stagnant water, under repeated loading, forms a high-speed flow and scours the base layer, causing fine aggregates to be passively carried out from the joints, resulting in pumping and grouting. This leads to the continuous expansion of the voided area and accelerates water damage to the concrete pavement. This invention provides a visual model test device that can simulate the formation and development mechanism of voids in cement concrete pavement slabs. The pavement slab model consists of multiple transparent surface layers and a roadbed. The load model can adjust its speed and load, and travels back and forth in a straight line on the surface layer. The rainfall model... This system can simulate rainfall of varying intensities and durations. The monitoring system includes a computer and pressure sensors, flow velocity sensors, and cameras connected to the computer. The pressure sensors monitor the pressure on the surface layer and subgrade, as well as the pressure changes caused by reduced contact area when voids occur. The flow velocity sensors monitor the velocity and direction of water within the voids. The computer calculates the dynamic water pressure within the voids based on the water flow velocity. By adjusting the speed and load of the load model, it can analyze how the dynamic water pressure within the voids changes with vehicle speed and weight, thereby assessing the scouring capacity of water flow on subgrade material particles under different working conditions. The camera monitors and records the initial formation and subsequent development of voids. This invention allows for the setting of different speeds and loads to conduct corresponding simulation tests, simulating the formation and development of voids under different working conditions. The test results can provide a basis for preventing concrete pavement voids, extending pavement service life, and ensuring pavement performance.

[0010] Further improved technical solution: The road model includes a surface layer and a roadbed set on top and bottom, and the pressure sensor, flow velocity sensor and camera are all placed between the surface layer and the roadbed.

[0011] A further improved technical solution: the surface layer is multiple and placed on the same plane, and the surface layer is transparent.

[0012] A further improved technical solution: The load model moves back and forth along the arrangement direction of the surface layer.

[0013] Further improved technical solution: The load model includes a traction end, a control end, a guide rail, and a load structure. The guide rail is placed between the traction end and the control end, and the load structure is communicatively connected to the control end. The load structure can move back and forth along the guide rail.

[0014] Further improved technical solution: The load structure includes a drive motor, a test wheel, a hydraulic system, and a speed sensor. The drive motor is connected to the test wheel for the test wheel to move back and forth along the track panel model. The hydraulic system is connected to the test wheel for adjusting the pressure of the test wheel on the track panel model. The speed sensor is used to detect the movement speed of the test wheel.

[0015] Further improved technical solution: The rainfall model includes a support, pipes, nozzles, a water pump, and a water storage tank. The support is placed above the road model, the pipes are placed on the support and connected to the water storage tank through the water pump, and the nozzles are placed on the pipes.

[0016] A further improved technical solution: The pipeline is equipped with a rotary control button for adjusting the water output and pressure of the nozzle.

[0017] This utility model also provides a method for simulating voids in cement concrete pavement slabs, including the following steps:

[0018] Step 1: The load model moves back and forth on the road model until the pressure sensor inside the road model detects that the pressure exceeds the threshold. The camera monitors and records the initial formation process of the void defect.

[0019] Step 2: The rainfall model experiences rainfall of different intensities and durations. The load model continues to move, and rainwater enters the void. The flow velocity sensor records the water flow velocity in the void area. The computer connected to the flow velocity sensor obtains the dynamic water pressure. The camera monitors and records the development process of the void.

[0020] Step 3: Monitor the surface layer failure in the road model and complete the simulation of voiding defects.

[0021] The beneficial effects of this utility model are as follows: This utility model provides a visual model test device that can simulate the formation and development mechanism of voids in cement concrete pavement panels. The pavement panel model consists of multiple transparent surface layers and a roadbed. The load model can adjust its speed and load, and travels back and forth in a straight line on the surface layer. The rainfall model can simulate rainfall of different intensities and durations. The monitoring system includes a computer and pressure sensors, flow velocity sensors, and cameras that are communicatively connected to the computer. The pressure sensors can monitor the pressure on the surface layer and the roadbed, as well as the pressure changes caused by the reduction of contact surface when voids occur. The flow velocity sensors can monitor the flow velocity and direction of water in the voids. The computer calculates the dynamic water pressure in the voids based on the water flow velocity. By adjusting the speed and load of the load model, it is possible to analyze how the dynamic water pressure in the voids changes with vehicle speed and weight, and thus evaluate the scouring ability of water flow on roadbed material particles under different working conditions. The camera can monitor and record the initial formation and subsequent development process of voids. This invention allows for the setting of different speeds and loads to conduct corresponding simulation tests, which are used to simulate the formation and development process of void defects under different working conditions. The test results can provide a basis for preventing void defects in concrete pavements, extending the service life of pavements, and ensuring the service performance of pavements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the test device for simulating voids in cement concrete pavement panels provided by this utility model.

[0023] Figure 2 This is a schematic diagram of the structure of the load model provided by this utility model acting on the pavement panel model;

[0024] Figure 3 This is a schematic diagram of the monitoring equipment provided by this utility model.

[0025] Attached reference numerals: 1. Pavement model, 11. Surface layer, 12. Subgrade.

[0026] 2. Load model, 21. Traction end, 22. Control end, 23. Guide rail, 24. Load structure, 241. Test wheel,

[0027] 3. Rainfall model; 31. Support frame; 32. Pipeline; 33. Sprinkler head; 34. Water pump; 35. Water storage tank; 36. Rotary control button.

[0028] 4. Monitoring equipment; 41. Pressure sensor; 42. Computer; 43. Flow sensor; 44. Camera.

[0029] 5. Voided area. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0031] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0032] Example 1:

[0033] Figure 1-3 The experimental setup for simulating voids in cement concrete pavement slabs is shown, including pavement slab model 1, load model 2, rainfall model 3, and monitoring equipment 4.

[0034] The load model 2 is placed on the road model 1 and can move back and forth on the road model 2;

[0035] The rainfall model 3 is used to generate rainfall above the road model 1;

[0036] The monitoring device 4 includes a computer 42 and a pressure sensor 41, a flow velocity sensor 43 and a camera 44 that are communicatively connected to the computer 42. The pressure sensor 41, the flow velocity sensor 43 and the camera 44 are all placed inside the pavement panel model 1.

[0037] Practice shows that temperature changes causing concrete slab warping and the minute plastic deformation of the base layer under aircraft loads can lead to initial voids at the bottom of the slab. Subsequently, rainfall flows into the base layer and void area along the road joints. The stagnant water forms a high-speed water flow under repeated loads, which scours the base layer, causing fine aggregates in the base layer to be passively carried out from the joints, resulting in pumping and slurry discharge. This leads to the continuous expansion of the void area 5, accelerating water damage to the concrete pavement. This utility model provides a visual model test device that can simulate the formation and development mechanism of void defects in cement concrete pavement slabs. The pavement slab model consists of multiple transparent surface layers and a roadbed. The load model can adjust its speed and load, and travels back and forth in a straight line on the surface layer. The rainfall model can simulate different rainfall patterns. The monitoring system for rainfall of the same intensity and duration includes a computer 42 and pressure sensors 41, flow velocity sensors 43, and cameras 44, all communicatively connected to the computer 42. The pressure sensors monitor the pressure on the surface layer and subgrade, as well as the pressure changes caused by the reduced contact area when voiding occurs. The flow velocity sensors monitor the flow velocity and direction of water within the voids. The computer calculates the dynamic water pressure within the voids based on the water flow velocity. By adjusting the speed and load of the load model, the system can analyze how the dynamic water pressure within the voids changes with vehicle speed and weight, thereby assessing the scouring capacity of water flow on subgrade material particles under different working conditions. The camera monitors and records the initial formation and subsequent development of voiding. This invention allows for the setting of different speeds and loads to conduct corresponding simulation tests, simulating the formation and development of voiding under different working conditions. The test results can provide a basis for preventing voiding in concrete pavements, extending pavement service life, and ensuring pavement performance.

[0038] In this embodiment, the load model moves back and forth in a straight line on the road model.

[0039] In this embodiment, the flow velocity sensor is a thermal flow velocity sensor, which is embedded at the bottom of the surface layer and the top of the roadbed to monitor the speed and direction of water flow. This allows for the calculation of the dynamic water pressure within the gap based on the water flow velocity. By adjusting the speed and load of the load model, it is possible to analyze how the dynamic water pressure within the gap changes with vehicle speed and weight, thereby assessing the scouring capacity of the water flow on the roadbed material particles under different operating conditions.

[0040] In this embodiment, the pressure sensor is a thin-film pressure sensor, which is fixed to the bottom of the surface layer and the top of the roadbed. By setting different loads and moving speeds on the load model, the pressure on the surface layer and roadbed is monitored, as well as the pressure change caused by the reduction of contact surface when voiding occurs. The thin-film pressure sensor is wirelessly connected to a computer.

[0041] In this embodiment, the camera is a miniature camera embedded in the bottom of the surface layer to monitor and record the initial formation and subsequent development of voiding defects. The miniature camera is wirelessly connected to a computer.

[0042] In this embodiment, the road model 1 includes a surface layer 11 and a roadbed 12 disposed on the upper and lower sides, and the pressure sensor 41, flow velocity sensor 43 and camera 44 are all placed between the surface layer 11 and the roadbed 12.

[0043] In this embodiment, there are multiple surface layers 11 placed on the same plane, and the surface layers 11 are transparent.

[0044] In this embodiment, the load model 2 moves back and forth along the arrangement direction of the surface layer 11.

[0045] In this embodiment, the load model 2 includes a traction end 21, a control end 22, a guide rail 23, and a load structure 24. The guide rail 23 is placed between the traction end 21 and the control end 22. The load structure 24 is communicatively connected to the control end 22. The load structure 24 can move back and forth along the guide rail 23.

[0046] In this embodiment, the load structure 24 includes a drive motor, a test wheel 241, a hydraulic system, and a speed sensor. The drive motor is connected to the test wheel 241 for the test wheel 241 to move back and forth along the track panel model 1. The hydraulic system is connected to the test wheel 241 for adjusting the pressure of the test wheel 241 on the track panel model 1. The speed sensor is used to detect the movement speed of the test wheel 241.

[0047] In this embodiment, both the traction end and the control end include frame structures connected to the guide rail, located at the front and rear ends of the load model, respectively.

[0048] In this embodiment, the frame outside the traction end consists of a rectangular frame structure located at the front end of the load structure, while the frame outside the control end consists of a rectangular tubular frame structure located at the rear end of the load structure. A guide rail connects the frames of the traction end and the control end, and the guide rail is arranged longitudinally along the pavement panel. The load structure travels back and forth in a straight line along the guide rail. The frames of the traction end and the control end provide a stable foundation for the load model, supporting the weight and movement of the load structure and ensuring stability and safety during pavement testing.

[0049] In this embodiment, the traction end includes an auxiliary power supply box connected to the load structure, and the control end includes a main power supply box, a vehicle signal distribution box, and a vehicle control system. The power supply box provides power support to the load structure, the vehicle signal distribution box is used to manage and distribute signals collected from the speed sensor and control unit, and the vehicle control system can control the speed and direction of the load structure.

[0050] In this embodiment, the drive motor is a reversible motor that provides power output for the movement of the test wheel. The test wheel acts directly on the surface layer, simulating the pressure exerted by actual vehicle tires on the road surface. The hydraulic system can adjust the simulated vehicle weight by changing its pressure, thereby accurately simulating the impact of different types of vehicles on the road surface. Photoelectric sensors are installed at both ends of the guide rail. When the load structure reaches the end of the guide rail, the position of the load structure is sensed by the blocking of the light beam. The photoelectric sensors send signals to the vehicle control system, instructing the load structure to change direction.

[0051] In this embodiment, the rainfall model 3 includes a support 31, a pipe 32, a nozzle 33, a water pump 34, and a water storage tank 35. The support 31 is placed above the road model 1, the pipe 32 is placed on the support 31 and connected to the water storage tank 35 through the water pump 34, and the nozzle 33 is placed on the pipe 32.

[0052] In this embodiment, one end of the pipe is fixed to a bracket, and nozzles are evenly distributed on the pipe. The water pump is installed on a water storage tank. The rotary control button can adjust the water output and pressure of the nozzles, thereby simulating rainfall of different intensities and durations.

[0053] In this embodiment, the pipe 32 is provided with a rotary control button 36 for adjusting the water output and pressure of the nozzle 33.

[0054] Example 2:

[0055] The simulation method for voids in cement concrete pavement slabs includes the following steps:

[0056] Step 1: Load model 2 moves back and forth on road model 1 until pressure sensor 41 in road model 1 detects that the pressure exceeds the threshold, and camera 42 monitors and records the initial formation process of voiding disease.

[0057] Step 2: Rainfall model 3 experiences rainfall of different intensities and durations, load model 2 continues to move, rainwater enters the voiding zone, flow velocity sensor 43 records the water flow velocity in the voiding zone 5, computer 42 connected to flow velocity sensor 43 obtains the dynamic water pressure, and camera 42 monitors and records the development process of the voiding zone.

[0058] Step 3: The failure of surface layer 11 in road model 1 was detected, and the simulation of voiding disease was completed.

[0059] In this embodiment, in step one, initially, a load model is applied to the pavement panel model, with the load structure located at one end of the guide rail. The driving speed and load are set, causing it to travel linearly back and forth on the surface layer. Due to the repeated action of the traffic load, the surface layer is in the elastic deformation stage, and the deformation caused by the load can be largely recovered. However, the base material, due to its viscoelastic-plastic properties, cannot fully recover its deformation. Pressure sensors on the surface layer and the roadbed can monitor changes in interlayer pressure. Combined with a camera, the formation process of voids is monitored and recorded, initially manifesting as interlayer discontinuity or interlayer peeling.

[0060] In this embodiment, in step two, rainfall of different intensities and durations is adjusted by a rainfall model. Rainwater will seep through the joints of the surface layer and accumulate in the gap between the surface layer and the roadbed. Based on the water flow velocity measured by the flow velocity sensor, the dynamic water pressure of the load model under different loads or driving speeds is calculated. With the help of a camera, the scouring behavior of the water flow on the roadbed granular material is determined.

[0061] As water erodes the subgrade material and traffic loads repeatedly apply, subgrade material particles are stripped away. Because the water flow velocity is fastest at the surface layer joints, and areas near the edges of the slabs are more susceptible to concentrated loads, subgrade material particles in these areas are more prone to stripping, leading to voiding primarily developing longitudinally and increasing the thickness of the voids. Pressure sensors can monitor the pressure on the underlying layers and subgrade under different load models. The extent of voiding can be determined by the interlayer pressure difference, and cameras monitor and record the development process of the voiding.

[0062] As the void expands longitudinally, only under heavier loads can the surface layer deform and reach the bottom of the void. Under normal loads, the surface layer deformation cannot reach the bottom of the void, causing the subgrade area bearing concentrated loads to move from the edge of the slab towards the inside of the void. As a result, the void at this stage mainly expands laterally, and the area of ​​the void continuously increases.

[0063] In this embodiment, in step three, the longitudinal and lateral expansion of the void defect alternates over time. When the void area and gap thickness become sufficiently large, the surface layer is under full tension due to increased load. If its maximum bending tensile stress exceeds the tensile strength, it will lead to surface layer failure. The simulation of the void defect is thus completed.

[0064] In this embodiment, the failure of the panel can be observed by a camera or by manual observation.

[0065] In this embodiment, Bernoulli's equation can be used to calculate the dynamic water pressure.

[0066] This device allows for simulation experiments with varying speeds and loads, simulating the formation and development of voids in concrete pavements under different working conditions. This helps analyze how loads and water erosion affect the formation, evolution, and expansion of voids. The experimental results will provide important evidence for preventing concrete pavement voids, extending pavement service life, and ensuring pavement performance.

[0067] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An experimental apparatus for simulating voids in cement concrete pavement slabs, characterized in that, It includes a pavement panel model (1), a load model (2), a rainfall model (3), and monitoring equipment (4). The load model (2) moves along the road panel model (1); The rainfall model (3) is used to generate rainfall above the road panel model (1); The monitoring device (4) includes a computer (42) and a pressure sensor (41), a flow rate sensor (43) and a camera (44) that are connected to the computer (42). The pressure sensor (41), the flow rate sensor (43) and the camera (44) are all placed inside the pavement model (1).

2. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 1, characterized in that, The road panel model (1) includes a surface layer (11) and a roadbed (12) set on the top and bottom, and the pressure sensor (41), flow velocity sensor (43) and camera (44) are all placed between the surface layer (11) and the roadbed (12).

3. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 2, characterized in that, The surface layer (11) is multiple and placed on the same plane, and the surface layer (11) is transparent.

4. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 3, characterized in that, The load model (2) moves back and forth along the arrangement direction of the surface layer (11).

5. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 1, characterized in that, The load model (2) includes a traction end (21), a control end (22), a guide rail (23), and a load structure (24). The guide rail (23) is placed between the traction end (21) and the control end (22). The load structure (24) is connected to the control end (22) in communication. The load structure (24) can move back and forth along the guide rail (23).

6. The experimental apparatus for simulating voids in cement concrete pavement panels according to claim 5, characterized in that, The load structure (24) includes a drive motor, a test wheel (241), a hydraulic system and a speed sensor. The drive motor is connected to the test wheel (241) for the test wheel (241) to move back and forth along the track panel model (1). The hydraulic system is connected to the test wheel (241) for adjusting the pressure of the test wheel (241) on the track panel model (1). The speed sensor is used to detect the movement speed of the test wheel (241).

7. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 1, characterized in that, The rainfall model (3) includes a support (31), a pipe (32), a nozzle (33), a water pump (34), and a water storage tank (35). The support (31) is placed above the pavement panel model (1). The pipe (32) is placed on the support (31) and connected to the water storage tank (35) through the water pump (34). The nozzle (33) is placed on the pipe (32).

8. The experimental apparatus for simulating voids in cement concrete pavement slabs according to claim 7, characterized in that, The pipe (32) is equipped with a rotary control button (36) for adjusting the water output and pressure of the nozzle (33).

Images