A stress-strain detection device for a modified concrete pavement

Abstract

The application relates to the technical field of modified concrete detection, in particular to a stress and strain detection device for a modified concrete pavement, which is used for solving the problem of poor effect of an existing pavement testing device; the device comprises a base and a clamping table connected to the base, a sample is installed on the clamping table, a rotating shaft is rotatably connected to a support, the output ends of multiple hydraulic rods are rotatably connected with testing wheels, and the hydraulic rods can adjust the pressure of the testing wheels on the sample after synchronous extension and contraction; the testing device comprises a first detection state and a second detection state; in the first detection state, multiple testing wheels roll on the same point on the sample in sequence; in the second detection state, two testing wheels reciprocally roll on the sample; the combination of the two detection modes of the device can analyze the local stress concentration effect and evaluate the overall structural durability, and the device provides multi-dimensional experimental basis for material optimization and structural design of the modified concrete pavement.

Description

Technical Field

[0001] This invention relates to the technical field of modified concrete testing devices, specifically a stress-strain testing device for modified concrete pavements. Background Technology

[0002] With the rapid development of the transportation industry, the load intensity, frequency, and complexity of highway pavements are constantly increasing. Traditional concrete pavements, due to insufficient fatigue resistance, crack resistance, and wear resistance, are prone to cracking, spalling, and subsidence, seriously affecting pavement service life and driving safety. To solve this problem, modified concrete materials, with their optimized mechanical and durability properties, are widely used in highway pavement engineering. By adding admixtures, fibers, polymers, and other modifying components, the fatigue strength, deformation resistance, and erosion resistance of concrete are significantly improved, making it one of the core materials for ensuring the long-term stable operation of high-grade highways.

[0003] The mechanical performance evaluation of modified concrete pavements is a crucial step in pavement engineering design, construction, and maintenance. Stress-strain characteristics directly determine the pavement's load-bearing capacity, fatigue resistance, and durability during actual service. Pavements face complex and diverse stress environments in actual operation. On one hand, the contact area between tires and the pavement during vehicle movement creates localized concentrated loads, which, under long-term repeated action, can easily lead to localized fatigue damage and subsequent crack propagation. On the other hand, the alternating loads generated by continuous vehicle traffic subject the pavement to repeated compaction, testing the overall crack resistance and durability of the pavement structure. Therefore, accurately obtaining the stress-strain characteristics of modified concrete under different stress modes is an important prerequisite for optimizing material mix proportions, rationally designing pavement structures, and extending pavement service life.

[0004] Currently, most existing stress-strain testing devices and methods for modified concrete pavements are designed for single stress modes, making it difficult to comprehensively simulate the complex stress scenarios encountered during actual pavement service. Some testing devices can only perform single-point compression tests under concentrated loads, simulating local stress concentration effects, but cannot reproduce the dynamic reciprocating contact process between the tire and the pavement during vehicle movement, making it difficult to assess the overall crack resistance and durability of the pavement under alternating loads. Other devices focus on large-area compaction tests, which can simulate overall stress conditions, but lack the accuracy to detect fatigue damage caused by local stress concentrations, and cannot accurately capture the deformation patterns of local pavement areas under long-term repeated concentrated loads.

[0005] Furthermore, existing testing devices suffer from poor flexibility and adaptability. Most devices can only perform a single testing function. To complete tests under different stress modes, different equipment must be replaced or complex structural adjustments must be made, which not only increases testing costs and operational difficulty but may also lead to a decrease in the consistency and comparability of test data due to equipment switching. At the same time, some testing devices lack precise control over load application, making it difficult to flexibly adjust the pressure, frequency, and mode of application according to actual testing needs. This results in deviations between the test results and the actual service condition of the pavement, hindering the provision of reliable multi-dimensional experimental evidence for the optimization of modified concrete materials and pavement structure design. Summary of the Invention

[0006] This invention provides a stress-strain testing device for modified concrete pavement to solve the problem of poor performance of existing pavement testing devices.

[0007] To alleviate the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0008] A stress-strain testing device for modified concrete pavement includes a base and a clamping platform connected to the base. A sample is installed on the clamping platform. A bracket is slidably connected to the base. A rotating shaft is rotatably connected to the bracket. Multiple hydraulic rods are arranged in a ring array on the side wall of the rotating shaft. The output ends of the multiple hydraulic rods are rotatably connected to test wheels. The pressure applied to the sample by the test wheels can be adjusted by the synchronous extension and retraction of the hydraulic rods.

[0009] The testing device includes a first detection state and a second detection state. In the first detection state, the bracket is locked to the base, and the rotating shaft rotates, so that the multiple test wheels roll sequentially on the same point on the sample.

[0010] In the second testing state, the rotating shaft is locked to the bracket, and the two test wheels contact the sample. The bracket slides back and forth on the base, so that the two test wheels roll back and forth on the sample.

[0011] Furthermore, a common oil pipe is connected between the multiple hydraulic rods, the oil pipe is coaxially arranged through the rotating shaft, and a rotary joint valve is connected to the end of the oil pipe at the rotating shaft.

[0012] An annular cover is fixedly connected to the middle of the bracket. The annular cover has a notch on its side wall near the sample, and multiple test wheels can roll on the inner wall of the annular cover and the sample.

[0013] Furthermore, a piston cylinder is fixedly connected to the bracket, and the piston cylinder is connected to the oil pipe through a rotary joint valve;

[0014] A piston plate is slidably connected inside the piston cylinder, a threaded rod is fixedly connected to the piston plate, a nut is threadedly connected to the threaded rod, and a limiting bracket that abuts against the nut is fixedly connected to the bracket.

[0015] When the shaft rotates, one of the hydraulic rods swings from an inclined state to a state perpendicular to the sample surface, and the test wheels at the ends of the remaining hydraulic rods contact the inner wall of the annular cover. When the hydraulic rod swings from an inclined state to a state perpendicular to the sample surface, it can gradually shorten, thereby gradually transferring hydraulic oil into the piston cylinder. When the hydraulic rod swings to a state close to perpendicular to the sample surface, the nut abuts against the limiting frame, and the pressure applied to the sample by the test wheels is at its maximum.

[0016] Furthermore, a motor for driving the rotating shaft to rotate is fixedly connected to the bracket.

[0017] Furthermore, a cylinder is fixedly connected to the bracket, a limit block is fixedly connected to the output end of the cylinder, and multiple limit rods are arranged in a circular array on the rotating shaft, with the multiple limit rods located between two adjacent hydraulic rods on the axial projection line of the rotating shaft.

[0018] The limiting block has a groove that mates with the limiting rod. When the cylinder extends and the limiting rod is inserted into the groove of the limiting block, the rotating shaft is locked to the bracket, and two of the multiple test wheels can contact the sample together.

[0019] Furthermore, a gear is rotatably connected to the bottom of the bracket, and a rack that meshes with the gear is provided on the base. The gear is driven to rotate reciprocally by an external power, thereby causing the bracket to slide reciprocally on the base.

[0020] Furthermore, the clamping platform is provided with a rectangular groove for placing the sample, and the sample is placed in the rectangular groove on the clamping platform.

[0021] Furthermore, each of the four sides of the rectangular groove is provided with a clamping strip, and a pin is fixedly connected to the clamping strip. The pin is slidably connected to the clamping platform, and a tension spring is connected between the pin cap of the pin and the outer wall of the clamping platform. The distance between the two clamping strips can reflect the lateral strain of the sample.

[0022] Furthermore, a detection plate is hinged to one side of the base, and multiple distance sensors are arrayed on the detection plate. After the support is moved away from the top of the sample, the detection plate can swing and cover the top of the sample, thereby detecting the longitudinal strain of the sample.

[0023] Furthermore, a hinge seat is fixedly connected to the side of the base, and a hinge shaft is fixedly connected to the detection plate, with the hinge shaft rotatably connected to the hinge seat.

[0024] The beneficial effects of this invention are analyzed as follows:

[0025] In the first testing state, the rotating shaft rotates, causing multiple test wheels to roll and apply pressure to the same testing point in sequence. In the second testing state, the rotating shaft stops rotating, and the support drives the test wheels to roll back and forth on the sample surface. By testing the sample through these two testing states, the stress-strain characteristics of modified concrete pavement under different stress modes can be better obtained. In the first testing state, since the test wheels act on the same point of the sample in sequence, the deformation of the pavement under long-term concentrated loads can be accurately simulated, such as fatigue damage caused by repeated rolling of the same area by vehicle tires. In the second testing state, the reciprocating rolling of the two test wheels can simulate the dynamic contact process between the tire and the pavement during vehicle driving, which is particularly suitable for evaluating the crack resistance of the pavement under alternating loads. The combined application of the two testing modes allows the device to analyze local stress concentration effects and evaluate the overall structural durability, providing multi-dimensional experimental evidence for the material optimization and structural design of modified concrete pavement. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the first detection state of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the second detection state of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure under the longitudinal stress-strain measurement state of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the detection station of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the gear in this invention;

[0031] Figure 6 This is a schematic diagram of the structure at the limiting block of the present invention;

[0032] Figure 7 This is a schematic diagram of the threaded rod of the present invention.

[0033] In the diagram: 100, base; 110, clamping platform; 120, clamping bar; 130, pin; 140, tension spring; 200, bracket; 210, annular cover; 220, rotating shaft; 221, motor; 230, oil pipe; 240, hydraulic rod; 250, test wheel; 260, piston cylinder; 270, piston plate; 271, threaded rod; 272, nut; 280, limit bracket; 300, cylinder; 310, limit block; 320, limit rod; 400, gear; 410, rack; 500, detection plate; 510, hinge shaft; 520, hinge seat. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Examples, such as Figures 1-7 As shown, a stress-strain testing device for modified concrete pavement includes a base 100 and a clamping platform 110 connected to the base 100. A sample is mounted on the clamping platform 110. A bracket 200 is slidably connected to the base 100, and a rotating shaft 220 is rotatably connected to the bracket 200. Multiple hydraulic rods 240 are arranged in a circular array on the side wall of the rotating shaft 220. Each output end of the hydraulic rods 240 is rotatably connected to a test wheel 250. The synchronous extension and retraction of the hydraulic rods 240 can adjust the pressure applied to the sample by the test wheel 250. The testing device includes a first testing state and a second testing state. In the first testing state, the bracket 200 is locked to the base 100, and the rotating shaft 220 rotates, causing the multiple test wheels 250 to roll sequentially on the same point on the sample. In the second testing state, the rotating shaft 220 is locked to the bracket 200, and two test wheels 250 contact the sample. The bracket 200 slides back and forth on the base 100, causing the two test wheels 250 to roll back and forth on the sample.

[0036] When conducting stress-strain tests on modified concrete pavement, the required test specimens are first prepared, and then the specimens are placed on the clamping table 110 to limit their position. The first and second detection states of the device are adjusted according to the test requirements.

[0037] In the first testing state, the relative positions of the lock bracket 200 and the base 100 are locked. First, one of the hydraulic rods 240 is controlled to be perpendicular to the sample surface. Then, the extension and retraction of the hydraulic rod 240 is adjusted so that the pressure applied to the sample by the test wheel 250 reaches the required level. After the adjustment is completed, the rotating shaft 220 is controlled to rotate so that multiple hydraulic rods 240 roll sequentially on the sample, which can continuously apply pressure to the same position of the sample. The time required to maintain the rotation of the rotating shaft 220 is maintained until the end of the experiment. The shape and size of the sample are then tested to obtain the stress and strain values.

[0038] In the second testing state, a new sample is prepared, and both test wheels 250 on the rotating shaft 220 are controlled to contact the sample surface. At this time, the midline of the angle between the two hydraulic rods 240 is perpendicular to the sample surface. The rotating shaft 220 is then locked so that it cannot rotate. Then, the two hydraulic rods 240 are controlled to extend synchronously so that the two test wheels 250 apply equal pressure to the sample. After adjustment, the support 200 is controlled to slide back and forth on the base 100, so that the two test wheels 250 repeatedly roll over a large area of ​​the sample surface. The support 200 is maintained for the time required for back and forth sliding until the end of the experiment. The shape and size polarity of the sample are then detected to obtain the stress and strain values.

[0039] The pressure between the test wheel 250 and the sample in the above two detection states can be obtained directly by using a sensor to detect the pressure between the two, or the pressure value can be obtained by detecting the pressure of the hydraulic oil.

[0040] The material of the test wheel 250 can be changed according to the simulation requirements, or the vehicle wheel can be used directly;

[0041] By testing the samples under the two aforementioned testing states, the stress-strain characteristics of modified concrete pavement under different stress modes can be better obtained. In the first testing state, since the test wheels 250 act on the same point of the sample sequentially, the deformation of the pavement under long-term concentrated loads can be accurately simulated, such as fatigue damage caused by repeated rolling of the same area by vehicle tires. In the second testing state, the reciprocating rolling of the two test wheels 250 can simulate the dynamic contact process between the tires and the pavement during vehicle operation, which is particularly suitable for evaluating the crack resistance of the pavement under alternating loads. The combined application of the two testing modes enables the device to analyze local stress concentration effects and evaluate the overall structural durability, providing multi-dimensional experimental evidence for the material optimization and structural design of modified concrete pavement.

[0042] Multiple hydraulic rods 240 are connected by an oil pipe 230, which is coaxially installed through a rotating shaft 220. A rotary joint valve is connected to the end of the oil pipe 230 on the rotating shaft 220. An annular cover 210 is fixedly connected to the middle of the bracket 200. The annular cover 210 has a notch on its side wall near the sample. Multiple test wheels 250 can roll on the inner wall of the annular cover 210 and the sample.

[0043] The test wheel 250 that applies pressure to the sample is in the working state, while the other test wheels 250 are in the idle state. The annular cover 210 is set to limit the extension of the hydraulic rod 240 corresponding to the test wheel 250 in the idle state, so as to prevent the hydraulic rod 240 corresponding to the test wheel 250 in the working state from depressurization and pressure reduction. At the same time, the annular cover 210 also serves as a protective function. In addition, it limits the extension and retraction of multiple hydraulic rods 240 to ensure that the dynamic balance of the rotating shaft 220 does not deviate significantly when rotating. The rotary joint valve on the oil pipe 230 ensures that the rotation of the rotating shaft 220 is not interfered with.

[0044] A piston cylinder 260 is fixedly connected to the bracket 200, and the piston cylinder 260 is connected to the oil pipe 230 through a rotary joint valve. A piston plate 270 is slidably connected inside the piston cylinder 260, and a threaded rod 271 is fixedly connected to the piston plate 270. A nut 272 is threadedly connected to the threaded rod 271. A limiting bracket 280 that abuts against the nut 272 is fixedly connected to the bracket 200. When the rotating shaft 220 rotates, one of the hydraulic rods 240 swings from an inclined state to a state perpendicular to the sample surface. The test wheels 250 at the ends of the other hydraulic rods 240 all contact the inner wall of the annular cover 210. When the hydraulic rod 240 swings from an inclined state to a state perpendicular to the sample surface, it can gradually shorten, thereby gradually transferring hydraulic oil into the piston cylinder 260. When the hydraulic rod 240 swings to a state close to perpendicular to the sample surface, the nut 272 abuts against the limiting bracket 280, and the pressure applied to the sample by the test wheel 250 is the maximum.

[0045] Adjust the position of nut 272 relative to threaded rod 271 according to the experimental requirements, thereby changing the relative position of piston plate 270 and piston cylinder 260. When the rotating shaft 220 rotates, when one of the test wheels 250 just disengages from the annular cover 210, the combined action of centrifugal force and gravity causes the hydraulic rod 240 corresponding to this test wheel 250 to extend. At this time, the hydraulic oil in the piston cylinder 260 enters the hydraulic rod 240. As the rotating shaft 220 continues to rotate, when the hydraulic rod 240 gradually changes from an inclined state to a state perpendicular to the sample surface, the hydraulic rod 240 gradually shortens. The hydraulic oil inside can be transferred to the piston cylinder 260, causing the piston plate 270 to slide. When the hydraulic rod 240 is close to vertical, the piston plate 270 slides until it drives nut 272 to abut against limit bracket 280. At this time, the sliding of piston plate 270 is blocked, so the hydraulic rod 240 will not shorten by a large amount, thus ensuring that the test wheel 250 can apply the required pressure to the sample.

[0046] In addition, since the pressure applied to the sample by the test wheel 250 is smaller when the hydraulic rod 240 is tilted, and the pressure applied to the sample is the greatest when the hydraulic rod 240 is perpendicular to the sample surface, it is possible to more accurately simulate the state of repeated rolling of the same area of ​​the road surface.

[0047] A motor 221 for driving the rotating shaft 220 to rotate is fixedly connected to the bracket 200.

[0048] Motor 221 is used to drive shaft 220 to rotate. A speed reducer can be set between the two to increase the torque output from motor 221 to shaft 220, ensuring that shaft 220 has enough power to rotate.

[0049] A cylinder 300 is fixedly connected to the support 200. A limit block 310 is fixedly connected to the output end of the cylinder 300. Multiple limit rods 320 are arranged in a ring array on the rotating shaft 220. The multiple limit rods 320 are located between two adjacent hydraulic rods 240 on the axial projection line of the rotating shaft 220. The limit block 310 has a groove that cooperates with the limit rod 320. When the cylinder 300 extends and the limit rod 320 is inserted into the groove of the limit block 310, the rotating shaft 220 is locked to the support 200, and two of the multiple test wheels 250 can contact the sample together.

[0050] In the second testing state, the rotation of the rotating shaft 220 needs to be locked. At this time, the rotating shaft 220 is controlled to rotate so that one of the limiting rods 320 is aligned with the limiting block 310. Then, the cylinder 300 is controlled to extend so that the limiting rod 320 is embedded in the groove of the limiting block 310, thereby locking the rotation of the rotating shaft 220. At this time, when the bracket 200 slides back and forth on the base 100, it will not cause the rotating shaft 220 to rotate, thus preventing a large deviation in the pressure applied to the sample by the two test wheels 250.

[0051] A gear 400 is rotatably connected to the bottom of the bracket 200, and a rack 410 that meshes with the gear 400 is provided on the base 100. The gear 400 is driven to rotate reciprocally by an external power, so that the bracket 200 slides back and forth on the base 100.

[0052] The bracket 200 and the base 100 can be locked together with screws, so that the device can operate in the first detection state when the two are locked. After the two are unlocked, the gear 400 is driven by external power to rotate back and forth, which in turn causes the gear 400 to roll back and forth on the rack 410, so that the bracket 200 slides back and forth on the base 100. At this time, the two test wheels 250 can repeatedly crush a large area of ​​the sample, simulating the dynamic contact process between the tire and the road surface during vehicle driving.

[0053] The clamping table 110 has a rectangular groove for placing the sample, and the sample is placed in the rectangular groove on the clamping table 110.

[0054] The sample is processed into a cuboid, and then the cuboid sample is placed in the rectangular groove on the clamping stage 110. The depth of the rectangular groove is matched with the thickness of the cuboid sample to avoid horizontal splashing when the sample breaks during testing.

[0055] Clamping bars 120 are provided on all four sides of the rectangular groove. Pins 130 are fixedly connected to the clamping bars 120. Pins 130 are slidably connected to the clamping table 110. A tension spring 140 is connected between the pin cap of the pin 130 and the outer wall of the clamping table 110. The distance between the two clamping bars 120 can reflect the transverse strain of the sample.

[0056] Four clamping bars 120 in the rectangular groove limit the rectangular specimen around its perimeter. A tension spring 140 provides power for the clamping bars 120 to clamp the specimen, ensuring that the four clamping bars 120 can stably limit the specimen. Before the test, the distance between two oppositely arranged clamping bars 120 is measured. After the test, the distance between the two oppositely arranged clamping bars 120 is measured again. By calculating the difference between the two measured values, the transverse stress and strain value of the specimen is obtained.

[0057] A detection plate 500 is hinged to one side of the base 100. Multiple distance sensors are arrayed on the detection plate 500. After the support 200 is moved away from the top of the sample, the detection plate 500 can swing and cover the top of the sample, thereby detecting the longitudinal strain of the sample.

[0058] After the test is completed, the support 200 is removed from the top of the sample. Then, the detection plate 500 is manually flipped and placed on the upper surface of the clamping table 110. The detection plate 500 first calibrates the position of the test and presses the test onto the clamping table 110 so that the lower surface of the sample is in contact with the bottom wall of the groove of the clamping table 110. Then, the distance sensor on the detection plate 500 is activated to measure the distance between the detection plate 500 and the upper surface of the sample. The distance sensor can be a light source type or an acoustic wave type. By processing the values ​​measured by multiple distance sensors, the longitudinal stress and strain values ​​of the sample are obtained.

[0059] In this process, the distance between the pressure-bearing part of the sample and the distance sensor is relatively long, while the distance between the non-pressure-bearing part and the distance sensor is relatively short. By obtaining multiple close distance values ​​measured by the distance sensors of multiple non-pressure-bearing parts, a reference value (which can be the average value) is confirmed. Then, multiple distance values ​​measured by the distance sensors of multiple pressure-bearing parts are obtained as deformation values. The data of multiple deformation values ​​and the corresponding orientation of the distance sensors are arranged, and the absolute value of the difference between each of the multiple distance values ​​and the reference value is calculated to obtain the longitudinal stress and strain values.

[0060] A hinge seat 520 is fixedly connected to the side of the base 100, and a hinge shaft 510 is fixedly connected to the detection plate 500. The hinge shaft 510 is rotatably connected to the hinge seat 520.

[0061] The engagement of the hinge base 520 and the hinge shaft 510 allows the detection plate 500 to swing freely relative to the base 100.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled 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 invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A stress-strain testing device for modified concrete pavement, characterized in that: The system includes a base (100) and a clamping platform (110) connected to the base (100). The sample is mounted on the clamping platform (110). A bracket (200) is slidably connected to the base (100). A rotating shaft (220) is rotatably connected to the bracket (200). Multiple hydraulic rods (240) are arranged in a ring array on the side wall of the rotating shaft (220). The output ends of the multiple hydraulic rods (240) are rotatably connected to a test wheel (250). The pressure applied to the sample by the test wheel (250) can be adjusted by the synchronous extension and retraction of the hydraulic rods (240). The detection device includes a first detection state and a second detection state. In the first detection state, the bracket (200) is locked to the base (100), and the rotating shaft (220) rotates, so that multiple test wheels (250) roll sequentially on the same point on the sample. In the second detection state, the rotating shaft (220) is locked to the bracket (200), and the two test wheels (250) contact the sample. The bracket (200) slides back and forth on the base (100), so that the two test wheels (250) roll back and forth on the sample. A common oil pipe (230) is connected between multiple hydraulic rods (240), and the oil pipe (230) is coaxially installed through the rotating shaft (220). A rotary joint valve is connected to the end of the oil pipe (230) of the rotating shaft (220). The bracket (200) is fixedly connected to the middle of an annular cover (210). The annular cover (210) has a notch on the side wall near the sample. Multiple test wheels (250) can roll on the inner wall of the annular cover (210) and the sample. A piston cylinder (260) is fixedly connected to the bracket (200), and the piston cylinder (260) is connected to the oil pipe (230) through a rotary joint valve. A piston plate (270) is slidably connected inside the piston cylinder (260), a threaded rod (271) is fixedly connected to the piston plate (270), a nut (272) is threadedly connected to the threaded rod (271), and a limiting bracket (280) that abuts against the nut (272) is fixedly connected to the bracket (200). When the shaft (220) rotates, one of the hydraulic rods (240) swings from an inclined state to a state perpendicular to the sample surface, and the test wheels (250) at the ends of the other hydraulic rods (240) all contact the inner wall of the annular cover (210). When the hydraulic rod (240) swings from an inclined state to a state perpendicular to the sample surface, it can gradually shorten, so that the hydraulic oil gradually transfers into the piston cylinder (260). When the hydraulic rod (240) swings to a state close to perpendicular to the sample surface, the nut (272) abuts against the limit frame (280), and the pressure applied to the sample by the test wheel (250) is the maximum.

2. The stress-strain detection device for modified concrete pavement according to claim 1, characterized in that: A motor (221) for driving the rotating shaft (220) to rotate is fixedly connected to the bracket (200).

3. The stress-strain detection device for modified concrete pavement according to claim 1, characterized in that: A cylinder (300) is fixedly connected to the bracket (200), and a limit block (310) is fixedly connected to the output end of the cylinder (300). A plurality of limit rods (320) are arranged in a ring array on the rotating shaft (220). The plurality of limit rods (320) are respectively located between two adjacent hydraulic rods (240) on the axial projection line of the rotating shaft (220). The limiting block (310) has a groove that cooperates with the limiting rod (320). When the cylinder (300) extends and the limiting rod (320) is embedded in the groove of the limiting block (310), the rotating shaft (220) is locked to the bracket (200), and two of the multiple test wheels (250) can contact the sample together.

4. The stress-strain detection device for modified concrete pavement according to claim 3, characterized in that: The bottom of the bracket (200) is rotatably connected to a gear (400), and the base (100) is provided with a rack (410) that meshes with the gear (400). The gear (400) is driven to rotate back and forth by an external power, so that the bracket (200) slides back and forth on the base (100).

5. The stress-strain detection device for modified concrete pavement according to claim 1, characterized in that: The clamping platform (110) has a rectangular groove for placing the sample, and the sample is placed in the rectangular groove on the clamping platform (110).

6. The stress-strain detection device for modified concrete pavement according to claim 5, characterized in that: Clamping strips (120) are provided on all four sides of the rectangular groove. Pins (130) are fixedly connected to the clamping strips (120). The pins (130) are slidably connected to the clamping platform (110). A tension spring (140) is connected between the pin cap of the pins (130) and the outer wall of the clamping platform (110). The distance between the two clamping strips (120) can reflect the transverse strain of the sample.

7. The stress-strain detection device for modified concrete pavement according to claim 6, characterized in that: A detection plate (500) is hinged to one side of the base (100). Multiple distance sensors are arrayed on the detection plate (500). After the support (200) is moved away from the upper part of the sample, the detection plate (500) can swing and cover the upper part of the sample, thereby detecting the longitudinal strain of the sample.

8. The stress-strain detection device for modified concrete pavement according to claim 7, characterized in that: A hinge seat (520) is fixedly connected to the side of the base (100), and a hinge shaft (510) is fixedly connected to the detection plate (500). The hinge shaft (510) is rotatably connected to the hinge seat (520).

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