Device and method for testing torsional or shear performance of recycled concrete beam test specimen

Abstract

The application discloses a device and method for testing the torsional performance or shearing performance of a recycled concrete beam test piece, which comprises a first jack, a force transmission gear is arranged on the piston rod of the first jack; a sleeve hoop is used for clamping the concrete test piece; a sleeve hoop gear is arranged on one side of the sleeve hoop, the force transmission gear and the sleeve hoop gear are engaged, the sleeve hoop is driven to rotate through the lifting of the first jack, and torsional damage of the concrete test piece is caused; a heating mechanism is used for heating the concrete test piece; a second jack is used for applying pressure to the shaft end of the concrete test piece, so that the concrete test piece is in the state of axial compression; and a third jack is used for applying pressure to the side of the sleeve hoop which is not provided with the sleeve hoop gear; the application can be used for testing the torsional and shearing strength of the concrete beam under the coupling action of high temperature and axial compression. The device tests the torsional and shearing strength of the structure under the coupling action of high temperature and axial compression.

Description

Technical Field

[0001] This invention relates to testing apparatus, specifically to an apparatus and method for testing the torsional or shear properties of recycled concrete beam specimens. Background Technology

[0002] Torsional and shear strengths of concrete beams are crucial mechanical parameters in engineering construction. Shear strength testing of concrete beams primarily focuses on assessing the beam's load-bearing capacity and failure mode under shear force. Currently, there are two main methods for measuring shear strength: three-point bending, where the beam is placed at two supports and the load is applied via a compression machine; and direct shear testing, where shear force is applied directly to a section of the beam by clamping both ends and applying forces in opposite directions. Torsional strength testing of concrete beams is mainly used to evaluate the beam's performance and torsional resistance under torsional loads. The most commonly used torsional strength test is the pure torsion test. This involves applying torques in opposite directions to both ends of the beam, typically using specialized clamps or torque application devices. This test directly determines the torsional strength and torsional stiffness of the concrete beam.

[0003] Currently, some researchers have made many improvements and innovations in order to directly obtain the shear and torsional properties of concrete beams.

[0004] Di Shengjie invented a shearing mechanism for multiple shear surfaces of undisturbed loess. In the device, the shearing unit is connected to the rotating unit and positioned within a test hole. Its extended end, in its extended state, contacts the surface of the annular soil mass, applying a vertical shear force to the annular soil mass subjected to a horizontal normal force. This method can obtain the shear properties of deep annular soil masses at different locations in loess regions.

[0005] Torsional and shear strengths of concrete beams are crucial mechanical parameters in engineering construction. Shear strength testing of concrete beams primarily focuses on assessing the beam's load-bearing capacity and failure mode under shear force. Currently, there are two main methods for measuring shear strength: three-point bending, where the beam is placed at two supports and the load is applied via a compression machine; and direct shear testing, where shear force is applied directly to a section of the beam by clamping both ends and applying forces in opposite directions. Torsional strength testing of concrete beams is mainly used to evaluate the beam's performance and torsional resistance under torsional loads. The most commonly used torsional strength test is the pure torsion test. This involves applying torques in opposite directions to both ends of the beam, typically using specialized clamps or torque application devices. This test directly determines the torsional strength and torsional stiffness of the concrete beam.

[0006] Currently, some researchers have made many improvements and innovations in order to directly obtain the shear and torsional properties of concrete beams.

[0007] Di Shengjie invented a shearing mechanism for multiple shear surfaces of undisturbed loess. In the device, a shearing unit is connected to a rotating unit and positioned within a test hole. Its extended end, in its extended state, contacts the surface of the annular soil mass, applying a vertical shear force to the annular soil mass subjected to a horizontal normal force. This invention can obtain the shear properties of deep annular soil masses at different locations in loess regions.

[0008] Patent document CN114235579A discloses a triaxial testing device for the compressive and shear strength of natural gas hydrate core samples. This device includes a pressure-resistant cylinder in which the core sample is placed; the pressure-resistant cylinder has a sealed pipeline connecting to an external tank; a confining pressure and temperature control unit is connected to the pipeline of a triaxial testing machine; and a data acquisition unit, located at the upper end of the pressure-resistant cylinder and fixedly connected to the triaxial testing machine, is used to record the changes in acoustic wave velocity before and after core fragmentation, and to record the transverse and longitudinal wave velocity time differences. This device can test the compressive and shear strength of core samples in a stable state of natural gas hydrates, obtain experimental data on the macroscopic mechanical properties of the core sample, and analyze the deformation mechanism of sedimentary layers.

[0009] Patent document CN116840074A discloses a device for testing the shear strength of concrete cube specimens. This device employs a horizontal pressure and vertical shearing method. A rectangular horizontal pressure frame is first fitted over the outside of the concrete specimen, and a normal pressure mechanism and roller array are positioned between the concrete specimen and the rectangular horizontal pressure frame. The shear strength of high-strength, high-performance concrete is tested by applying pressure to the right and left normal pressure sections on the side of the concrete specimen through the normal pressure mechanism and the rectangular horizontal pressure frame. The device has the advantages of simple structure, ease of operation, and wide applicability.

[0010] Patent document CN219512012U discloses a cable torsional stiffness testing device. The device fixes a specimen, corresponding to a torsion assembly, for clamping the other end of the cable under test; a torsional torque sensor is connected to the torsion assembly to test the torsional torque borne by the cable under test; an angle sensor is connected to the cable under test to test the torsion angle of the cable under test; the testing method includes the following steps: preparing a sample; installing the sample into the testing device; providing a test torsional force and collecting the torsional torque and torsional angle; analyzing the relationship between the torsional angle and the torsional torque; and calculating the torsional stiffness.

[0011] Patent document CN112067463A discloses a testing device for the torsional resistance of insulators. This device is mounted on a frame, with one end of a test sample rotatably mounted on the frame via a brake, and the rotation axis of the test sample is vertically positioned. An eccentric rotor is horizontally slidable on the frame, with the other end of the test sample inserted into the eccentric rotor, and the centerline of the test sample coaxial with the rotation axis of the eccentric rotor. A rotary drive mechanism has its output shaft inserted into the eccentric rotor, and the output shaft of the rotary drive mechanism is coaxial with the axis of the eccentric rotor. A linear drive mechanism drives the rotary drive mechanism to move up and down, allowing the output shaft of the rotary drive mechanism to be inserted into or separated from the eccentric rotor. This solution can automatically test the torsional resistance of insulators, with high testing efficiency and accurate results.

[0012] However, most of the aforementioned devices focus only on solving for a single mechanical parameter under shear or torsion conditions. Most cannot perform shear or torsion tests on experimental components under the coupled effects of high temperature and axial compression to obtain their corresponding mechanical properties. Most shear and torsion tests require precise alignment of the component with the experimental fixture to ensure the load is applied at the center of the specimen. High precision machining of the components is also required. Summary of the Invention

[0013] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for testing the torsional or shear properties of recycled concrete beam specimens, so as to simultaneously test the torsional or shear properties of concrete beam specimens under the coupled action of high temperature and axial compression.

[0014] To achieve the above objectives, the technical solution of the present invention is as follows:

[0015] In a first aspect, the present invention provides a testing device for the torsional or shear properties of recycled concrete beam specimens, comprising:

[0016] The first jack, the piston rod of the first jack is equipped with a force transmission gear;

[0017] A clamp is used to hold a concrete specimen; a clamp gear is provided on one side of the clamp, and the force transmission gear meshes with the clamp gear so that the clamp can be rotated by the lifting and lowering of the first jack, causing the concrete specimen to be torsionally destroyed.

[0018] The first force sensor is used to detect and record the force state of the first jack.

[0019] A heating mechanism used to heat concrete specimens.

[0020] The second jack is used to apply pressure to the axial end of the concrete specimen, so that the concrete specimen is under axial compression.

[0021] The third jack is used to apply pressure to the side of the clamp that does not have a clamp gear.

[0022] The third force sensor is used to detect and record the force state of the third jack.

[0023] Optionally, the heating mechanism includes two mullite bricks, with a mullite brick with a U-shaped groove between the two mullite bricks, and a U-shaped heat-conducting carbon rod disposed in the mullite brick with the U-shaped groove. The terminal of the U-shaped heat-conducting carbon rod passes through the first mullite brick or the second mullite brick and is connected to a three-phase high-current transformer to control the temperature.

[0024] Optionally, after the hoop clamps the concrete specimen, the hoop is placed on the mullite brick with U-shaped groove, and both ends of the concrete specimen are placed on the two mullite bricks of the heating mechanism.

[0025] Optionally, the torsional or shear performance testing device for the recycled concrete beam specimen further includes a platform with a cross-shaped groove. The horizontal groove of the cross-shaped groove is used to place the heating mechanism and the second jack, and the middle intersection of the cross-shaped groove is the placement position of the sleeve. One side of the vertical groove of the cross-shaped groove is used to place the third front jack, and the upper part of the other side of the vertical groove is used to install a frame, which is used to install the first jack.

[0026] Optionally, a loading plate is provided between the second jack and the axial end of the concrete specimen; the second jack, the loading plate, and the second force sensor constitute an axial compression mechanism.

[0027] Optionally, the first force sensor is disposed on the top of the first jack; the second force sensor is disposed on the top of the second jack; and the third force sensor is disposed on the top of the third front jack.

[0028] Optionally, the third jack is placed on a mullite brick; the third jack, the mullite brick, and the third force sensor constitute a shearing mechanism.

[0029] Optionally, the first jack, the second jack, and the third jack are all hydraulic jacks.

[0030] Optionally, a second force sensor is used to detect and record the force state of the second jack.

[0031] Secondly, the present invention provides a method for testing the torsional or shear properties of recycled concrete beam specimens, based on the aforementioned testing apparatus, comprising:

[0032] Step 1: Make a steel base with a cross-shaped groove;

[0033] Step 2: Make the clamp with the gear and the first jack with the force transmission gear, and assemble the two;

[0034] Step 3: Construct the heating mechanism;

[0035] Step 4: Combine the components from Step 2 and Step 3 and install the axial compression mechanism for the concrete specimen;

[0036] A frame with a first jack and a first force sensor is welded onto a pedestal with a cross-shaped groove. A hoop with a concrete specimen and a heating mechanism are placed into the groove of the pedestal. The terminals of a U-shaped heat-conducting carbon rod are connected to a three-phase high-current transformer through a mullite brick to control the temperature. An axial compression mechanism, namely a steel loading plate, a second force sensor, and a second jack, is placed on top of the concrete specimen to put the concrete specimen under axial compression.

[0037] Step 5: Construct a shearing mechanism, consisting of a mullite brick, a third force sensor, and a third jack; place the third force sensor on top of the third jack to record the force state of the third jack.

[0038] Step 6: Place the shearing mechanism from step 5 into the grooved base from step 4;

[0039] First, before conducting the shear test, retract the piston rod of the first jack.

[0040] Then, the prestressed tensioning oil pump controls the raising and lowering of the third jack. The piston rod of the third jack presses against the steel structure hoop. After the pressure is continued, shear failure occurs at the steel structure hoop of the concrete specimen.

[0041] Step 7: Calculate torsional stress;

[0042] According to the torsional stress calculation formula τ=T / A; where T is the torque, T=F×r1, F is the force value obtained through the first force sensor on the first jack, r1 is the lever arm; and A is the cross-sectional area of ​​the concrete specimen.

[0043] Step 8: Calculate the shear stress;

[0044] According to the formula for shear stress τ = F / A, where F is the force value obtained from the third force sensor on the third jack, and A is the cross-sectional area of ​​the concrete specimen.

[0045] Compared with the prior art, the advantages of this invention are as follows:

[0046] This invention can be used to test the torsional and shear strength of concrete beams under high temperature and axial compression coupling. Traditional structural testing often focuses only on torsional (torque) or shear (shear force) tests, while in practical applications, structures may be affected by both forces simultaneously, as well as environmental influences. This device tests the torsional and shear strength of a structure under high temperature and axial compression coupling. This device integrates the functions of torsional and shear resistance testing, rather than a single function, making it more suitable for testing a variety of structural mechanical properties. Attached Figure Description

[0047] Figure 1 A schematic diagram of the overall structure of the testing device for the torsional or shear properties of recycled concrete beam specimens provided in the embodiments of this application;

[0048] Figure 2 This is a schematic diagram of the pedestal structure;

[0049] Figure 3 This is a schematic diagram of the assembly of the first jack and the clamp.

[0050] Figure 4 This is a schematic diagram showing the installation of the first jack within the frame.

[0051] Figure 5 This is a schematic diagram of the heating mechanism;

[0052] Figure 6 This is a schematic diagram of a device for testing the torsional performance of concrete beam specimens under the coupled action of high temperature and axial compression.

[0053] Figure 7 This is a schematic diagram of the shearing mechanism.

[0054] Figure 8 This is a schematic diagram of a device for testing the shear performance of concrete beam specimens under the coupled action of high temperature and axial compression.

[0055] Figure 9 A schematic diagram for solving torsional stress;

[0056] Figure 10 Schematic diagram for solving shear stress

[0057] In the diagram: 1. Base; 2. Second jack; 3. First jack; 4. First force sensor; 5. Frame; 6. Mullite brick; 7. Thermally conductive carbon rod; 8. Concrete specimen; 9. Oil pipe; 10. Hoop; 11. Loading plate; 12. Mullite brick with U-groove; 13. Third jack; 14. Second force sensor; 15. Third force sensor. Detailed Implementation

[0058] Example:

[0059] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0060] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0061] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can be a mechanical connection or an electrical connection; they can be a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0063] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact, or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0065] See Figure 1 As shown, the torsional or shear performance testing device for recycled concrete beam specimens provided in this embodiment mainly includes a first jack 2, a sleeve 10, a first force sensor 4, a heating mechanism, a second jack 2, a second force sensor 14, a third jack 13, and a third force sensor 15.

[0066] Among them, such as Figure 2 As shown, the piston rod of the first jack 2 is equipped with a force-transmitting gear; the clamp 2 is used to clamp the concrete specimen 8, and a clamp gear is provided on one side of the clamp 8. The force-transmitting gear and the clamp gear mesh with each other so that the clamp 8 is rotated by the lifting and lowering of the first jack 2, thereby causing the concrete specimen 8 to undergo torsional failure; the first force sensor 4 is used to detect and record the force state of the first jack 2, thereby obtaining the force value required for rotation. Specifically, the first force sensor 4 is set on the top of the first jack 2 to record the force state of the jack. The data of the first force sensor 4 is collected by the Donghua data acquisition system. The lifting and lowering of the first jack 2 is achieved by connecting the prestressed tensioning oil pump to the first jack through the oil pipe 9.

[0067] The heating mechanism is used to heat concrete specimens, and the heating temperature is adjustable.

[0068] The second jack 2 is used to apply pressure to the axial end of the concrete specimen 8, so that the concrete specimen is in an axial compression state, and the second force sensor 14 is used to detect and record the force state of the second jack.

[0069] The third jack 13 is used to apply pressure to the side of the clamp 10 that does not have a clamp gear; the third force sensor 15 is used to detect and record the force state of the third jack 13.

[0070] Therefore, it can be seen that the torsional or shear performance testing device for recycled concrete beam specimens provided in this embodiment can simultaneously test the torsional or shear performance of concrete beam specimens under high temperature and axial compression coupling under the synergistic effect of the first jack, the second jack, the third jack and the heating mechanism.

[0071] In one specific embodiment, such as Figure 5 As shown, the heating mechanism includes two mullite bricks 6, with a mullite brick 12 with a U-shaped groove between them. A U-shaped heat-conducting carbon rod 7 is installed in the mullite brick 12 with the U-shaped groove. The terminals of the U-shaped heat-conducting carbon rod pass through the mullite brick 6 and are connected to a three-phase high-current transformer to control the temperature. When the clamp 10 clamps the concrete specimen 8, since the clamp 10 protrudes from the surface of the concrete specimen 8, it is placed on the mullite brick 12 with the U-shaped groove to heat the concrete specimen 8. The two ends of the concrete specimen 8 are placed on the two mullite bricks 6 of the heating mechanism.

[0072] Most existing shear and torsional tests require precise alignment of the component with the test fixture to ensure that the load is applied at the center of the specimen, which places high demands on the component's machining accuracy. Therefore, in a preferred embodiment, the torsional or shear performance testing fixture for the recycled concrete beam specimen further includes a pedestal 1, such as... Figure 2 As shown, the pedestal is provided with a cross-shaped groove; as Figure 7 As shown, the horizontal groove of the cross-shaped groove is used to place the heating mechanism and the second jack 2. The middle intersection of the cross-shaped groove is the placement position of the hoop 10. One end of the concrete specimen 8 abuts against the inner wall of one end of the horizontal groove, and the other end of the concrete specimen 8 is where the second jack 2 is placed. One side of the vertical groove of the cross-shaped groove is used to place the third front jack, as shown. Figure 1 and 4 As shown, the frame 5 is installed on the upper side of the other side of the vertical groove, and the first jack 3 is installed on the frame 5. In this way, the first jack 3, the second jack 2, the third jack 13 and the heating mechanism and other components are placed on the platform without the need for alignment with the experimental fixture. The entire device has low machining precision and is more convenient for testing.

[0073] In one specific embodiment, in order to avoid damage to the shaft end of the concrete specimen 8 by the second jack 2, a loading plate 11 is provided between the second jack 2 and the shaft end of the concrete specimen 8.

[0074] In one specific embodiment, the second force sensor 14 is disposed on the top of the second jack 2; the third force sensor 15 is disposed on the top of the third front jack 13. The third jack 13 is placed on the mullite brick 6. The first jack 3, the second jack 2, and the third jack 13 are all hydraulic jacks. The platform 1 is a steel platform, the frame is a high-temperature alloy steel frame, the sleeve is a steel structure sleeve, and the loading plate is a steel loading plate.

[0075] Accordingly, this embodiment also provides a method for manufacturing a testing device for the torsional or shear properties of recycled concrete beam specimens, specifically including the following steps:

[0076] Step 1: Fabricate a steel base with a cross-shaped groove. This configuration is achieved using laser cutting and welding techniques on steel plates, such as... Figure 2 As shown.

[0077] Step 2: Construct a steel structure with a locally fitted gear and a first jack with a force-transmitting gear. The gears of these two components mesh together, causing the jack to lift and rotate, thus inducing torsional failure in the concrete specimen. To obtain the required force value for torsion, the first jack with the force-transmitting gear and a first force sensor are fixed within a high-temperature alloy steel frame. The first force sensor is placed on top of the first jack to record the force state of the jack; the data from the force sensor is collected by the Donghua data acquisition system. The lifting and lowering of the first jack is achieved by connecting a prestressing tensioning oil pump to the first jack via an oil pipe, as shown below. Figure 3-4 As shown.

[0078] Step 3: Construct a high-temperature heating mechanism. For example... Figure 5 As shown, it consists of two mullite bricks, a mullite brick with a U-shaped groove, and a U-shaped thermally conductive carbon rod. The U-shaped thermally conductive carbon rod is placed on the mullite brick with the U-shaped groove, and the terminal of the U-shaped thermally conductive carbon rod passes through the mullite brick to connect to a three-phase high-current transformer to achieve temperature control.

[0079] Step 4: Assemble the components from steps 2 and 3 and install the axial compression mechanism for the concrete specimen. Weld a high-temperature alloy steel frame with a first jack and force sensor onto a grooved high-temperature alloy steel pedestal. Place the steel structure hoop with the concrete specimen and the high-temperature heating mechanism into the groove of the high-temperature alloy steel pedestal. The U-shaped heat-conducting carbon rod's terminals pass through mullite bricks and are connected to a three-phase high-current transformer to control the temperature. Place the axial compression mechanism—a steel loading plate, a second force sensor, and a second jack—on top of the concrete specimen, thus placing the concrete specimen under axial compression. Figure 6 As shown.

[0080] Step 5: Create the cutting mechanism. For example... Figure 7As shown, it consists of a mullite brick, a third force sensor, and a third jack. The third force sensor is placed on top of the third jack to record the force state of the third jack.

[0081] Step 6: Place the shearing mechanism from Step 5 onto the grooved high-temperature alloy steel platform from Step 4. First, before conducting the shear test, retract the piston rod of the first jack. Then, the prestressed tensioning pump controls the raising and lowering of the third jack. The piston rod of the third jack presses against the steel structure clamp. After further pressurization, shear failure occurs at the steel structure clamp of the concrete specimen, thus realizing the shear failure of the concrete component under the coupled action of high temperature and axial compression. Figure 8 As shown

[0082] Step 7: Calculate torsional stress. The torsional stress is calculated using the formula τ = T / A. Where T is the torque, T = F × r1, F is the force value (obtainable from the first force sensor on the first jack), r1 is the lever arm, and A is the cross-sectional area of ​​the concrete specimen. Figure 9 As shown.

[0083] Step 8: Calculate the shear stress. According to the formula for shear stress τ = F / A, where F is the force value (obtainable from the third force sensor on the third jack) and A is the cross-sectional area of ​​the concrete specimen, the shear stress can be derived from the formula. For example... Figure 10 As shown.

[0084] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A testing device for the torsional or shear properties of recycled concrete beam specimens, characterized in that, include: The first jack, the piston rod of the first jack is equipped with a force transmission gear; A clamp is used to hold a concrete specimen; a clamp gear is provided on one side of the clamp, and the force transmission gear meshes with the clamp gear so that the clamp can be rotated by the lifting and lowering of the first jack, causing the concrete specimen to be torsionally destroyed. The first force sensor is used to detect and record the force state of the first jack. A heating mechanism used to heat concrete specimens. The second jack is used to apply pressure to the axial end of the concrete specimen, so that the concrete specimen is under axial compression. The third jack is used to apply pressure to the side of the clamp that does not have a clamp gear. The third force sensor is used to detect and record the force state of the third jack. The heating mechanism includes two mullite bricks, with a mullite brick with a U-shaped groove between the two mullite bricks. A U-shaped heat-conducting carbon rod is placed in the mullite brick with the U-shaped groove. The terminal of the U-shaped heat-conducting carbon rod passes through the first mullite brick or the second mullite brick and is connected to a three-phase high-current transformer to control the temperature. After the hoop clamps the concrete specimen, the hoop is placed on the mullite brick with U-shaped groove, and both ends of the concrete specimen are placed on the two mullite bricks of the heating mechanism. It also includes a base, which is provided with a cross-shaped groove; the horizontal groove of the cross-shaped groove is used to place the heating mechanism and the second jack, and the middle intersection of the cross-shaped groove is the placement position of the sleeve; one side of the vertical groove of the cross-shaped groove is used to place the third jack, and the upper part of the other side of the vertical groove is used to install a frame, which is used to install the first jack. The third jack is placed on the mullite brick; the third jack, the mullite brick, and the third force sensor constitute a shearing mechanism.

2. The testing device for the torsional or shear properties of recycled concrete beam specimens as described in claim 1, characterized in that, A loading plate is provided between the second jack and the axial end of the concrete specimen; the second jack, the loading plate, and the second force sensor constitute an axial compression mechanism.

3. The testing device for the torsional or shear properties of recycled concrete beam specimens as described in claim 2, characterized in that, The first force sensor is disposed on the top of the first jack; the second force sensor is disposed on the top of the second jack; and the third force sensor is disposed on the top of the third jack.

4. The testing device for the torsional or shear properties of recycled concrete beam specimens as described in claim 3, characterized in that, The first, second, and third jacks are all hydraulic jacks.

5. The testing device for the torsional or shear properties of recycled concrete beam specimens as described in claim 4, characterized in that, The second force sensor is used to detect and record the force state of the second jack.

6. A method for testing the torsional or shear properties of recycled concrete beam specimens, based on the testing apparatus described in claim 5, characterized in that, include: Step 1: Make a steel base with a cross-shaped groove; Step 2: Make a sleeve with a gear and a first jack with a force transmission gear, and assemble the two; the gears between the sleeve with a gear and the first jack with a force transmission gear mesh with each other, so that the first jack lifts and drives the steel structure sleeve to rotate, causing the concrete specimen to be torsionally damaged. Step 3: Construct the heating mechanism; Step 4: Combine the clamp with gear in step 2 and the first jack with force transmission gear in step 3 with the heating mechanism, and install the axial compression mechanism for the concrete specimen. A frame with a first jack and a first force sensor is welded onto a pedestal with a cross-shaped groove. A hoop with a concrete specimen and a heating mechanism are placed into the groove of the pedestal. The terminals of a U-shaped heat-conducting carbon rod are connected to a three-phase high-current transformer through a mullite brick to control the temperature. An axial compression mechanism, namely a steel loading plate, a second force sensor, and a second jack, is placed on top of the concrete specimen to put the concrete specimen under axial compression. Step 5: Construct a shearing mechanism, consisting of a mullite brick, a third force sensor, and a third jack; place the third force sensor on top of the third jack to record the force state of the third jack; Step 6: Place the shearing mechanism from step 5 into the grooved base from step 4; First, before conducting the shear test, retract the piston rod of the first jack. Then, the prestressed tensioning oil pump controls the lifting and lowering of the third jack. The piston rod of the third jack presses against the steel structure sleeve. After the pressure is continued, shear failure occurs at the steel structure sleeve of the concrete specimen, thus realizing the shear failure of the concrete component under the coupling action of high temperature and axial compression. Step 7: Calculate the torsional stress; According to the torsional stress calculation formula, τ1 = T / A; Where T is the torque, T=F1×r1, F1 is the force value obtained by the first force sensor on the first jack, r1 is the lever arm; A is the cross-sectional area of ​​the concrete specimen. Step 8: Calculate the shear stress; According to the formula for shear stress τ2= F2 / A, F2 is the force value obtained by the third force sensor on the third jack, and A is the cross-sectional area of ​​the concrete specimen.

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