A torsional shear pull integrated detection device for detecting interlayer bonding strength of a road surface

Abstract

The application discloses a torsional shear and pull-out integrated detection device for detecting interlayer bonding strength of a road surface, and relates to the technical field of asphalt road surface bonding strength detection devices.The torsional shear and pull-out integrated detection device for detecting interlayer bonding strength of a road surface combines torsional shear detection and pull-out detection together, can effectively save manpower and resources, and only needs to be provided with a corresponding torsional shear detection device or a pull-out detection device when detecting the torsional shear strength and the pull-out strength of the interlayer of the road surface, and the whole device is detected by a detection personnel applying a torque to a hand wheel, the torque is amplified to a required torque through a torsional force multiplier, and therefore, only a small torque needs to be applied to the hand wheel to complete the torsional shear detection and the pull-out detection, so that the whole device does not need to be driven by a motor, the weight of the torsional shear and pull-out integrated detection device is greatly reduced, the device is convenient to carry, the operation method is simple, and the detection efficiency can be effectively improved.

Description

Technical Field

[0001] This invention relates to the technical field of asphalt pavement bonding strength testing equipment, and in particular to an integrated torsion-shear-pull-out testing device for testing the interlayer bonding strength of pavement. Background Technology

[0002] The quality of asphalt pavement in highway engineering is closely related to highway lifespan, driving safety, and driving comfort, and is therefore highly valued by highway builders. Currently, various testing methods and equipment exist to test various performance indicators of asphalt pavement. For example, the "Specifications for Field Testing of Highway Subgrade and Pavement" (JTG3450-2019), which came into effect on April 1, 2020, added the "Interlayer Bond Strength Test Method" (T0985-2019). This method mainly tests the interlayer bond strength of asphalt pavement structural layers, including tensile strength and torsional shear strength. If the interlayer bond strength (tensile strength and torsional shear strength) of asphalt pavement structural layers is insufficient, the internal stress state of the pavement will differ significantly from the design requirements, easily causing quality problems such as pavement shoving, peeling, and loosening, leading to a shortened pavement service life.

[0003] Currently, the pull-out strength and torsional shear strength between asphalt pavement structural layers are generally tested using two different devices: one to measure torque and the other to measure tensile force. Both devices are important equipment for testing pavement performance. However, it is inconvenient to carry both devices at the same time when testing pavement performance, which also leads to low testing efficiency. Moreover, existing devices for testing pull-out strength and torsional shear strength usually require motor drive, making the equipment complex, large in size and heavy. Summary of the Invention

[0004] The purpose of this invention is to propose an integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of pavement. The main body can switch between torque detection and tensile force detection, combining torsion-shear detection and pull-out detection. This device is easy to carry and can effectively save manpower and resources. It solves the problem that the current method of using two separate devices to detect the pull-out strength and torsion-shear strength of asphalt pavement structural layers is inconvenient to carry and has low detection efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] An integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces includes a main body, a torsion-shear testing device, and a pull-out testing device. The main body includes a fixed frame, a handwheel, a torque multiplier, a transmission mechanism, and a main shaft. The torque multiplier is mounted on the top surface of the fixed frame. The input shaft of the torque multiplier is connected to the handwheel, and the output shaft of the torque multiplier is connected to the main shaft. The transmission mechanism is drivenly connected to the main shaft.

[0007] The transmission mechanism is used to connect the torsion-shear detection device or the pull-out detection device. When the transmission mechanism and the torsion-shear detection device are connected, the integrated torsion-shear and pull-out detection device is in torsion-shear mode, used to detect the torsion-shear strength between pavement structural layers. The transmission mechanism drives the torsion-shear detection device to rotate synchronously with the main shaft. When the transmission mechanism and the pull-out detection device are connected, the integrated torsion-shear and pull-out detection device is in pull-out mode, used to detect the pull-out strength between pavement structural layers. The transmission mechanism drives the pull-out detection device to move up and down along the main shaft.

[0008] Further explanation: the transmission mechanism includes a spline nut, a lead screw nut, and a first flange. The spline nut and the lead screw nut are respectively connected to the main shaft for transmission, and the spline nut is located above the lead screw nut. The first flange is installed at the bottom of the lead screw nut and is used to connect the torsion shear detection device or the pull-out detection device.

[0009] When the first flange is connected to the torsion and shear detection device, the spline nut and the lead screw nut are connected as one unit and rotate synchronously with the main shaft; when the first flange is connected to the pull-out detection device, the spline nut and the lead screw nut are in a separated state, and the lead screw nut moves up and down along the main shaft.

[0010] To further explain, the main shaft is provided with a raceway and a slideway on its outside. The raceway is spirally arranged around the outside of the main shaft, and the slideway is vertically arranged on the outside of the main shaft.

[0011] The spline nut has a limiting member inside, which matches the slide rail. The limiting member is inserted into the slide rail, so that the spline nut can slide up and down along the main shaft, or the spline nut can rotate synchronously with the main shaft.

[0012] The steel ball inside the lead screw nut moves along the raceway, causing the lead screw nut to move up and down along the main shaft, or causing the lead screw nut and the main shaft to rotate relative to each other.

[0013] Further explanation: the spline nut is a hollow cylindrical structure, the limiting member is provided on the inner surface of the spline nut, the bottom of the spline nut is provided with a retaining member, and the top of the lead screw nut is provided with a retaining groove. The retaining member and the retaining groove match. When the first flange is connected to the torsion and shear detection device, the retaining member is embedded in the retaining groove, so that the spline nut and the lead screw nut are connected.

[0014] Further explanation: the spline nut includes a connecting part and a base, the base is installed at the bottom of the connecting part, and the base is sleeved on the outside of the connecting part;

[0015] The connecting part is a hollow cylindrical structure, and the limiting member is provided on the inner surface of the connecting part;

[0016] The base has a locking device at its bottom and a slot at its top. The locking device and the slot are matched. When the first flange is connected to the torsion and shear detection device, the locking device is embedded in the slot, so that the spline nut and the lead screw nut are connected.

[0017] Further explanation: the pull-out detection device includes a second flange, a tension sensor, a pull-out rod, and a pull-out disc. The second flange is used to connect to the first flange, and the first flange, the tension sensor, the pull-out rod, and the pull-out disc are connected in sequence.

[0018] Further explanation: the mounting frame includes a mounting platform, the torque multiplier is mounted on the top surface of the mounting platform, and the output shaft of the torque multiplier passes through the mounting platform and is connected to the main shaft;

[0019] The main body also includes two limiting posts, which are respectively installed on the bottom surface of the mounting platform and located on the left and right sides of the transmission mechanism. The limiting post guide groove is vertically provided on the side of the transmission mechanism.

[0020] The second flange is provided with limiting sliders at its left and right ends respectively. The limiting sliders are matched with the guide groove. After the first flange is connected to the pull-out detection device, the limiting sliders are engaged in the guide groove.

[0021] Further explanation: the pull-out detection device also includes a universal joint and a positioning nut, the top end of the universal joint is connected to the second flange, and the bottom end of the universal joint is connected to the tension sensor;

[0022] The bottom of the tension sensor is provided with a connector, the connector is hollow inside and has an internal thread, the pull rod has an external thread, and the connector and the pull rod are threadedly connected.

[0023] The positioning nut is sleeved on the outside of the pull rod, and the positioning nut is used to fix the position of the pull rod.

[0024] To further explain, the bottom end of the pull rod is provided with a limiting ball, the diameter of which is larger than the diameter of the pull rod;

[0025] The top surface of the drawing disc is provided with a connecting mechanism, which is a cylinder, and the limiting ball is rotatably connected to the connecting mechanism.

[0026] Further explanation: the torque-shear detection device includes a third flange, a torque sensor, a universal coupling, and a torque-shear disc. The torque sensor is mounted on the third flange, which is used to connect to the first flange. One end of the universal coupling is connected to the torque sensor, and the other end is connected to the torque-shear disc.

[0027] To further explain, the torque multiplier is a planetary gear reducer.

[0028] Further explanation: the fixing frame includes at least three support columns, the top ends of which are mounted on the bottom surface of the mounting platform;

[0029] The mounting platform is circular, and the support columns are evenly distributed on the circumference of the mounting platform.

[0030] The above technical solution has the following beneficial effects: The integrated torsion-shear and pull-out testing equipment of this technical solution is an integrated setup that combines the two functions of torsion-shear testing and pull-out testing, which can effectively save manpower and resources. When testing the interlayer torsion-shear strength and pull-out strength of the road surface, only the corresponding torsion-shear testing device or the pull-out testing device needs to be installed. The entire device is operated by the testing personnel applying a torque to the handwheel, and this torque is amplified to the required torque by the torque multiplier. Therefore, only a small torque needs to be applied to the handwheel to complete the torsion-shear and pull-out testing, so that the entire device does not require motor drive. This greatly reduces the weight of the integrated torsion-shear and pull-out testing equipment, making it not only easy to carry, but also simple to operate, and can effectively improve the testing efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the main body of an integrated torsion-shear-pull-out testing device according to an embodiment of the present invention;

[0032] Figure 2 yes Figure 1 A magnified view of a portion at point T shown;

[0033] Figure 3 yes Figure 1 The diagram shown is a structural schematic of the integrated torsion-shear-pull-out testing device in torsion-shear mode.

[0034] Figure 4 yes Figure 3 A schematic diagram of the torsion shear detection device in the integrated torsion shear pull-out testing equipment shown;

[0035] Figure 5 yes Figure 1The diagram shown illustrates the structure of the integrated torsion-shear-pull-out testing device in pull-out mode.

[0036] Figure 6 yes Figure 5 A schematic diagram of the pull-out testing device in the integrated torsion-shear-pull-out testing equipment shown;

[0037] Figure 7 yes Figure 6 A schematic diagram of the connection between the pull rod and the pull disc in the pull-out testing device shown;

[0038] Figure 8 yes Figure 1 A schematic diagram showing the connection relationship between the transmission mechanism and the main shaft in an integrated torsion-shear-pull-out testing equipment.

[0039] Figure 9 yes Figure 8 The diagram shows the structure of the main shaft.

[0040] Figure 10 A schematic diagram of the connection relationship between the transmission mechanism and the main shaft in another embodiment of the present invention;

[0041] Figure 11 yes Figure 10 A cross-sectional view of the schematic diagram showing the connection relationship between the transmission mechanism and the main shaft;

[0042] Figure 12 yes Figure 10 Schematic diagram of the structure of a center spline nut;

[0043] Figure 13 yes Figure 12 Front view of the center spline nut;

[0044] The components include: main body 1, fixed frame 11, handwheel 12, torque multiplier 13, transmission mechanism 14, main shaft 15, limiting column 16, coupling 17, mounting platform 111, support column 112, spline nut 141, lead screw nut 142, first flange 143, raceway 151, slideway 152, clamp A 1411, limiting component 1412, connecting part 1413, base 1414, clamp B 1415, and slot 1421.

[0045] Torque-shear detection device 2, third flange 21, torque sensor 22, universal coupling 23, torsion-shear disc 24;

[0046] Pull-out detection device 3, second flange 31, tension sensor 32, pull-out rod 33, pull-out disc 34, universal joint 35, positioning nut 36, limit slider 311, connector 321, limit ball 331, connecting mechanism 341. Detailed Implementation

[0047] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of this invention, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, features defined with "first" and "second" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis.

[0049] In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] The following is combined Figures 1 to 7 This invention describes an integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces, according to an embodiment of the present invention.

[0052] An integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces includes a main body 1, a torsion-shear testing device 2, and a pull-out testing device 3. The main body 1 includes a fixed frame 11, a handwheel 12, a torque multiplier 13, a transmission mechanism 14, and a main shaft 15. The torque multiplier 13 is mounted on the top surface of the fixed frame 11. The input shaft of the torque multiplier 13 is connected to the handwheel 12, and the output shaft of the torque multiplier 13 is connected to the main shaft 15. The transmission mechanism 14 is connected to the main shaft 15 in a transmission manner.

[0053] The transmission mechanism 14 is used to connect the torsion-shear detection device 2 or the pull-out detection device 3. When the transmission mechanism 14 and the torsion-shear detection device 2 are connected, the integrated torsion-shear and pull-out detection device is in torsion-shear mode and is used to detect the torsion-shear strength between pavement structure layers. The transmission mechanism 14 drives the torsion-shear detection device 2 to rotate synchronously with the main shaft 15. When the transmission mechanism 14 and the pull-out detection device 3 are connected, the integrated torsion-shear and pull-out detection device is in pull-out mode and is used to detect the pull-out strength between pavement structure layers. The transmission mechanism 14 drives the pull-out detection device 3 to move up and down along the main shaft 15.

[0054] It is worth noting that the integrated torque-shear-pull testing equipment of this technical solution includes a main body 1, a torque-shear testing device 2, and a pull-out testing device 3. The handwheel 12 and the torque multiplier 13 are fixed by the fixing frame 11. The output shaft of the torque multiplier 13 is connected to the main shaft 15. The transmission mechanism 14 is connected to the main shaft 15. At the same time, the transmission mechanism 14 is used to connect the torque-shear testing device 2 or the pull-out testing device 3. When performing torque-shear testing or pull-out testing, the operator applies torque to the handwheel. Through the torque multiplier 13, the applied torque can be amplified by a specific factor and transmitted to the torque-shear testing device 2 or the pull-out testing device 3, which is connected to the transmission mechanism 14, so as to complete the torque-shear testing or pull-out testing.

[0055] The integrated torsion-shear and pull-out testing equipment of this technical solution is an integrated unit that combines the two functions of torsion-shear testing and pull-out testing. This effectively saves manpower and resources. When testing the interlayer torsion-shear strength and pull-out strength of the road surface, only the corresponding torsion-shear testing device 2 or the pull-out testing device 3 needs to be installed. The entire device is operated by the testing personnel applying a torque to the handwheel 12. This torque is amplified to the required torque by the torque multiplier 13. Therefore, only a small torque needs to be applied to the handwheel 12 to complete the torsion-shear and pull-out testing, so the entire device does not require a motor drive. This greatly reduces the weight of the integrated torsion-shear and pull-out testing equipment, making it not only easy to carry but also simple to operate, effectively improving testing efficiency.

[0056] Preferably, the main body 1 further includes a coupling 17, through which the output shaft of the torque multiplier 13 and the main shaft 15 are connected, enabling the torque and speed of the output shaft of the torque multiplier 13 and the main shaft 15 to be consistent.

[0057] Further explanation: The transmission mechanism 14 includes a spline nut 141, a lead screw nut 142, and a first flange 143. The spline nut 141 and the lead screw nut 142 are respectively connected to the main shaft 15 for transmission, and the spline nut 141 is located above the lead screw nut 142. The first flange 143 is installed at the bottom of the lead screw nut 142. The first flange 143 is used to connect the torsion shear detection device 2 or the pull-out detection device 3.

[0058] When the first flange 143 is connected to the torsion and shear detection device 2, the spline nut 141 and the lead screw nut 142 are connected as one unit and rotate synchronously with the main shaft 15; when the first flange 143 is connected to the pull-out detection device 3, the spline nut 141 and the lead screw nut 142 are in a separated state, and the lead screw nut 142 moves up and down along the main shaft 15.

[0059] It is worth noting that the lead screw nut 142 and the main shaft 15 are connected in a transmission manner to form a ball screw structure, which can convert the rotational motion of the main shaft 15 into the axial motion of the lead screw nut 142. Through the cooperation of the lead screw nut 142 and the main shaft 15, the horizontal torque generated by the rotation of the handwheel 12 can be converted into a vertical pulling force, thereby realizing the pulling detection function of the integrated torque-shear-pull detection device. In the torque-shear mode, the horizontal torque provided by the handwheel 12 needs to be directly transmitted to the lower torque-shear detection device 2. At this time, the spline nut 141 is required. The spline nut 141 and the main shaft 15 cooperate to form a rectangular spline structure. The function of the rectangular spline is opposite to that of the ball screw. The rectangular spline can freely transmit torque but will not transmit tensile force in the axial direction. That is, the spline nut 141 can slide freely up and down along the main shaft 15 but cannot rotate relative to the shaft. Therefore, in the torque-shear mode, the spline nut 141 and the lead screw nut 142 need to be connected together. This combination structure can neither rotate relative to the main shaft 15 nor slide axially relative to the main shaft 15, which is equivalent to a completely fixed connection. At this time, the torque generated by the handwheel 12 can be amplified by the torque multiplier 13 and then transmitted downward to the road surface being tested, thereby realizing the torque-shear detection function.

[0060] The main shaft is provided with a raceway and a slideway on its outside. The raceway is spirally arranged around the outside of the main shaft, and the slideway is vertically arranged on the outside of the main shaft.

[0061] The spline nut has a limiting member inside, which matches the slide rail. The limiting member is inserted into the slide rail, so that the spline nut can slide up and down along the main shaft, or the spline nut can rotate synchronously with the main shaft.

[0062] The steel ball inside the lead screw nut moves along the raceway, causing the lead screw nut to move up and down along the main shaft, or causing the lead screw nut and the main shaft to rotate relative to each other.

[0063] Preferably, the slide rails are provided in multiple ways, and the multiple slide rails are evenly spaced on the outside of the main shaft. The limiting members are also provided in multiple ways, and the multiple limiting members are evenly spaced on the inside of the spline nut. The multiple limiting members and the multiple slide rails correspond one-to-one, which can make the connection between the spline nut and the main shaft more reliable, so that the spline nut can rotate synchronously with the main shaft and slide up and down along the main shaft more stably.

[0064] Preferably, the cross-section of the limiting component and the slide is rectangular, which makes the spline nut more resistant to torsion and prevents relative rotation between the spline nut and the main shaft, thereby making the data of torsional shear strength and tensile strength obtained by shearing more accurate.

[0065] Further explanation: the spline nut is a hollow cylindrical structure, the limiting member is provided on the inner surface of the spline nut, the bottom of the spline nut is provided with a locking member A, and the top of the lead screw nut is provided with a locking groove. The locking member and the locking groove match. When the first flange is connected to the torsion and shear detection device, the locking member is embedded in the locking groove, so that the spline nut and the lead screw nut are connected.

[0066] It is worth noting that in this technical solution, the spline nut 141 is a hollow cylindrical steel component with multiple clips A1411 at its bottom. At the same time, the spline nut 141 has multiple clips 1412 inside. The multiple clips A1412 inside the spline nut 141 are respectively embedded in multiple slides 152 inside the main shaft 15, so that the spline nut 141 will rotate with the main shaft 15 and the rotation speed is the same as that of the main shaft 15. At the same time, the spline nut 141 will also move up and down along the main shaft 15.

[0067] The lead screw nut 142 is a special component consisting of several steel balls. The steel balls move continuously along the raceway 151 on the main shaft 15, allowing the lead screw nut 142 to move up and down along the main shaft 15. Simultaneously, the lead screw nut 142 can rotate relative to the main shaft 15, meaning its rotational speed is different from that of the main shaft 15. The bottom of the lead screw nut 142 has multiple slots 1421, the dimensions of which match the dimensions of multiple retaining pieces A1411 below the spline nut 141. When the integrated torsion-shear-pull-out testing equipment is in torsion-shear mode, the retaining pieces 1411 and the slots 1421 work together to fix the spline nut 141 and the lead screw nut 142 together, preventing relative rotation or axial sliding between the combined structure and the main shaft 15, thus ensuring the torsion-shear test can proceed.

[0068] A first flange 143 is attached below the lead screw nut 142 to facilitate connection with the torsion shear detection device 2 and the pull-out detection device 3.

[0069] In another technical solution of the present invention, the spline nut 141 includes a connecting part 1413 and a base 1414. The base 1414 is installed on the bottom of the connecting part 1413 and is sleeved on the outside of the connecting part 1413.

[0070] The connecting part 1413 is a hollow cylindrical structure, and the limiting member 1412 is provided on the inner surface of the connecting part 1413;

[0071] The base 1414 has a retainer B1415 at its bottom and a retainer groove at its top. The retainer and the retainer groove match. When the first flange is connected to the torsion and shear detection device, the retainer is embedded in the retainer groove, so that the spline nut and the lead screw nut are connected.

[0072] Specifically, in the above technical solution, the spline nut 141 adopts a combination of connecting part 1413 and base 1414, which makes the overall structure of the spline nut 141 lighter and reduces the weight of the spline nut 141, while reducing the manufacturing cost of the spline nut 141, thereby further reducing the weight of the integrated torsion shearing and drawing testing equipment and making it easier to carry.

[0073] Further explanation: The pull-out detection device 3 includes a second flange 31, a tension sensor 32, a pull-out rod 33, and a pull-out disc 34. The second flange 31 is used to connect with the first flange 143, and the first flange 143, the tension sensor 32, the pull-out rod 33, and the pull-out disc 34 are connected in sequence.

[0074] Further explanation: the mounting frame 11 includes a mounting platform 111, the torque multiplier 13 is mounted on the top surface of the mounting platform 111, and the output shaft of the torque multiplier 13 passes through the mounting platform 111 and is connected to the main shaft 15.

[0075] The main body 1 also includes two limiting posts 16, which are respectively installed on the bottom surface of the mounting platform 111 and located on the left and right sides of the transmission mechanism 14. The limiting posts 16 are provided with a guide groove on the side closer to the transmission mechanism 14.

[0076] The second flange 31 is provided with limiting sliders 311 at its left and right ends respectively. The limiting sliders 311 and the guide groove are matched. After the first flange 143 is connected to the pull-out detection device 3, the limiting sliders 311 are engaged in the guide groove.

[0077] It is worth noting that the pull-out testing device 3 includes a second flange 31, a tension sensor 32, a pull-out rod 33, and a pull-out disc 34. The pull-out testing device 3 is connected to the road surface specimen to be pulled out via the pull-out disc 34. The tension sensor 32 measures the tension force when the road surface fails under tension, thereby completing the pull-out test. The second flange 31 has the same dimensions as the first flange 143. When installing the pull-out testing device 3, the first flange 143 and the second flange 312 are connected with screws, thereby integrating the pull-out testing device 3 and the main body 1 into one unit.

[0078] The second flange 312 is provided with limiting sliders 311 on both sides. The limiting sliders 311 can be adapted to the guide groove in the limiting post 16, thereby restricting the rotation of the screw nut 142. That is, when the torsion shear pull-out integrated testing equipment is in the pull-out state, the screw nut 142 can only move up and down along the main shaft 15, so that pull-out testing can be performed. In addition, it should be noted that when using the pull-out testing device 3, the spline nut 141 and the screw nut 142 should be separated to prevent the pull-out testing device 3 from rotating along the main shaft, so as to better test the pull-out strength between road layers.

[0079] Further explanation: the pull-out detection device 3 also includes a universal joint 35 and a positioning nut 36. The top end of the universal joint 35 is connected to the second flange 31, and the bottom end of the universal joint 35 is connected to the tension sensor 32.

[0080] The bottom of the tension sensor 32 is provided with a connector 321. The connector 321 is hollow inside and has an internal thread. The pull rod 33 has an external thread. The connector 321 and the pull rod 33 are threadedly connected.

[0081] The positioning nut 36 is sleeved on the outside of the pull rod 33, and the positioning nut 36 is used to fix the position of the pull rod 33.

[0082] Specifically, the tension sensor 32 and the second flange 31 are connected by a universal joint 35, allowing the pull-out detection device 3 to better adapt to the road surface environment. A cylindrical connector 321 with internal threads is fixedly connected to the bottom of the tension sensor 32. The internal thread of the connector 321 matches the thread on the outer circumference of the pull rod 33. The pull rod 33 can be adjusted to a suitable height by screwing it in or out of the connector 321. After the height is adjusted, the positioning nut 36 is screwed to the top to hold the connector 321 in place, fixing the pull rod 33 through a self-locking effect. This makes the connection between the connector 321 and the pull rod 33 more secure. Furthermore, because the tension sensor 32 and the pull rod 33 are height-adjustable and fixed by the positioning nut 36 in this technical solution, the pull-out detection device 3 better adapts to the road surface environment and is more conducive to detecting the pull-out strength between road surface layers.

[0083] To further explain, the bottom end of the pull rod 33 is provided with a limiting ball 331, the diameter of which is larger than the diameter of the pull rod 33;

[0084] The top surface of the drawing plate 34 is provided with a connecting mechanism 341, which is a cylinder, and the limiting ball 331 is rotatably connected to the connecting mechanism 341.

[0085] Traditionally, the pull-out disc and pull-out rod are connected by a threaded connection. After connection, the pull-out rod is perpendicular to the pull-out disc, and the structure is fixed and cannot be moved. Therefore, when measuring the pull-out force, the point of application is not at the connection position. This can easily lead to bending moments due to inaccurate alignment of the pull-out part during pull-out force testing, resulting in inaccurate measurement results and a short service life. In this technical solution, the cooperation of the limiting ball 331 and the connecting mechanism 341 allows the pull-out rod 33 and the pull-out disc 34 to be movably connected, preventing bending moments from affecting the test results. This allows for more accurate measurement of the pull-out force of asphalt pavement and extends its service life.

[0086] Specifically, the connecting mechanism 341 has an annular groove at its center, an inlet on its outer side, and a limiting hole at its top. The inlet includes a round hole and a square hole. The bottom ends of the limiting ball 331 and the pull rod 33 pass through the inlet of the connecting mechanism 341 into the annular groove. The limiting hole is used to prevent the limiting ball 331 from coming out of the limiting hole (the diameter of the limiting hole is smaller than the diameter of the limiting ball 331, but larger than the diameter of the pull rod 33), thus restricting the limiting ball 331 to move only in the annular groove. In use, the limiting ball 331 part of the pull rod 33 is aligned with the inlet and inserted into the interior of the connecting mechanism. The pull rod 33 body can be inserted through the square hole and aligned to be perpendicular to the pull plate 34. Then the pull detection device is started. The limiting ball 331 (steel ball) of the pull rod cannot come out of the limiting hole because it is restricted by the limiting hole, so it does not affect the pull detection.

[0087] This technical solution allows the bottom of the pull rod to be directly inserted into the connecting mechanism 341 from the inlet, making installation and disassembly simple and avoiding excessive wear, thus extending its service life compared to traditional structures.

[0088] Further explanation: The torque-shear detection device 2 includes a third flange 21, a torque sensor 22, a universal coupling 23, and a torque-shear disc 24. The torque sensor 22 is mounted on the third flange 21, which is used to connect to the first flange 143. One end of the universal coupling 23 is connected to the torque sensor 22, and the other end is connected to the torque-shear disc 24.

[0089] It is worth noting that the torsion shear testing device 2 is connected to the road surface specimen to be torsion sheared via the torsion shear disc 24. The torque sensor 22 is used to measure the torque when the asphalt pavement is damaged by torsion shear, thereby obtaining the torsion shear strength between the pavement structural layers.

[0090] In the torsion-shear testing device 2, the third flange 21 has the same dimensions as the first flange connected below the lead screw nut. The third flange 21 and the first flange 143 are connected as a single unit using screws, putting the integrated torsion-shear and pull-out testing device into torsion-shear mode. A universal coupling 23 connects the main shaft 15 to the torsion-shear disc, ensuring identical torque for both. The main shaft 15 can move up and down along the universal coupling 23, which has universal joints at both the top and bottom, allowing the torsion-shear testing device to better adapt to road conditions. When using the torsion-shear device, the spline nut 141 and the lead screw nut 142 are connected by a clamp and slot, ensuring that both rotate only with the main shaft 15 at the same speed, without vertical movement, thus achieving torsion-shear testing.

[0091] Preferably, the universal coupling 23 in this technical solution is a telescopic universal coupling, allowing the main shaft 15 to move up and down along the universal coupling 23, thereby better adapting to the road surface environment. Specifically, the telescopic universal coupling has a telescopic function. By using the telescopic universal coupling to connect the torque sensor 22 and the torque shear disc 24, the entire torque shear detection device and the torque shear disc do not require height adjustment when connected, making operation simpler and faster. At the same time, by using the telescopic universal coupling as the connecting structure, the telescopic universal coupling only transmits torque, avoiding the generation of horizontal or vertical forces on the structure under test during the measurement process, ensuring more accurate measurement results.

[0092] Preferably, during torsion-shear testing, the integrated torsion-shear-pull-out testing equipment also includes an extension arm (not shown in the figure). In existing equipment, to balance the large torque during torsion-shear testing, the equipment is mainly fixed to the testing device using methods that damage the road surface, such as nailing. This technical solution uses an extension arm to utilize friction for fixing, thus avoiding additional damage to the road surface and reducing road surface damage. The main function of the extension arm is to balance the torque. During torsion-shear testing, the operator fixes the outer end of this arm to counteract the reverse torque transmitted from the road surface during torsion-shear. The specific shape of the extension arm resembles a "three-meter ruler." One end of the extension arm is connected to the fixing frame 11 of the integrated torsion-shear-pull-out testing equipment, and the other end is connected to a reliable structure (e.g., road crash barriers, corrugated beam guardrail posts, stably parked vehicles, etc.). During torsion-shear testing, when the handwheel is turned, the torque multiplier 13 generates a huge reverse torque, which can easily cause the integrated torsion-shear and pull-out testing equipment to lose balance. When searching for road structures with high torsion-shear strength, the self-weight of the integrated torsion-shear and pull-out testing equipment alone is insufficient to provide enough torque to counteract it. Therefore, an extension arm is set to maintain the overall stability of the equipment. According to the mechanical formula, when the required torque is constant, the longer the extension arm, the smaller the required force. After calculation, the length of the extension arm in this scheme is designed to be about 3 meters. Due to the long length of the extension arm, it is not shown in the figure.

[0093] Preferably, the torque multiplier 13 is a planetary gear reducer.

[0094] Planetary gear reducers, also known as planetary speed reducers or gear reducers, are power transmission mechanisms that utilize gear speed converters to reduce the rotational speed of an applied force to the desired speed while obtaining a larger torque. Planetary gear reducers have advantages such as small size, light weight, high load-bearing capacity, long service life, smooth operation, and low noise. This technical solution uses a planetary gear reducer as the torque multiplier 13, allowing the operator to apply torque to the handwheel. This torque is amplified to a specific factor and transmitted to the lower torsion-shear detection device 2 or pull-out detection device 3. The entire integrated torsion-shear-pull-out detection equipment operates by the operator applying a torque to the handwheel, which is then amplified to the required torque by the planetary gear reducer. Therefore, only a small torque needs to be applied to the handwheel to complete torsion-shear and pull-out tests. Consequently, this integrated torsion-shear-pull-out detection equipment does not require a motor drive, significantly reducing the overall weight of the equipment. This simplifies the equipment structure, makes it easy to carry, and can be well applied to road performance testing. Furthermore, this integrated torsion-shear-pull-out detection equipment is characterized by high efficiency and high economy.

[0095] Further explanation: the fixing frame 11 includes at least three support columns 112, the top ends of which are mounted on the bottom surface of the mounting platform 111;

[0096] The mounting platform 111 is circular, and the support columns 112 are evenly distributed on the circumference of the mounting platform 111.

[0097] Specifically, the mounting platform 111 is fixed by the support column 112, which facilitates the installation of the torque multiplier 13, the transmission mechanism 14, the main shaft 15, the torque shear detection device 2, and the pull-out detection device 3.

[0098] It is worth noting that, traditionally, torsion shear testing and tensile testing are performed by two separate and different devices. This technical solution combines torsion shear testing and tensile testing through the principle of ball screws. The main body 1 can convert between torque and tensile testing, and combining torsion shear testing and tensile testing can effectively save manpower and resources.

[0099] Specifically, the pavement structure is a discontinuous layered structure, with the surface layer and the underlying structural layers bonded together by asphalt. This asphalt layer is called the bonding layer. After pavement construction is completed, the bonding strength of the bonding layer needs to be tested to check the construction quality. Currently, the main testing indicators are torsional shear strength and tensile strength. The method for testing the interlayer bond strength of pavement using the integrated torsional shear and pull-out testing equipment of this technical solution is as follows:

[0100] Before testing, a circular groove is drilled into the road surface using a core drill. When the depth of the downward cut is greater than the thickness of the surface layer, the surface layer cylinder inside the drill bit is connected to the lower road surface only through the adhesive layer. At this point, the stress resistance of the adhesive layer can be tested.

[0101] Torque-shear test: according to Figure 3 The "torsion-shear mode" assembly device is then connected and extended, the distal end of the lever arm is fixed, the torsion-shear disc is adhered to the surface of the structure to be tested, and then the handwheel is rotated. The torque generated by rotating the handwheel is amplified by the torque multiplier 13 and then transmitted sequentially along the main shaft, the first flange, the third flange 21, the torque sensor, the universal coupling, the torsion-shear disc, and the surface layer, finally reaching the adhesive layer. When the adhesive layer is damaged by torsion-shear, the torsion-shear strength can be read by the torque sensor.

[0102] Pull-out test: Similar to the torsion-shear test, according to... Figure 5 The "pull-out mode" assembly device is then used. The handwheel is turned until the adhesive layer is broken by the pull force, and the pull-out strength can be read by the pull force sensor.

[0103] The force checks for the torque multiplier, lead screw nut, and spline nut in this technical solution are as follows:

[0104] 1. Regarding the force verification of the torque multiplier:

[0105] A torque multiplier (planetary gear reducer) is a device that increases torque for the operator. Since the output power does not exceed the input power, the output speed is lower than the input speed. The torque multiplier conforms to the formula: Power = Torque × Speed. With small power changes, the speed of the planetary gear reducer decreases significantly, effectively increasing torque. Therefore, a torque multiplication can be achieved through a planetary gear reducer, amplifying it by 5 to 125 times, with a maximum output torque of approximately 50,000 Nm. Table 1 below shows the parameter information for some commonly used planetary gear reducer models:

[0106] Table 1. Parameter information of commonly used planetary gear reducers

[0107]

[0108] The maximum output torque of the integrated torsion-shear and pull-out testing equipment in this technical solution is designed to be 500 N·m. When using a model 35 planetary gear reducer, only 25 N·m of torque is required at the input end. When the handwheel diameter is 0.5 m, only 50 N of force is required at both ends. Therefore, the testing personnel only need to apply a small torque to the handwheel to complete the torsion-shear and pull-out tests.

[0109] 2. Force verification of the lead screw nut and rectangular spline:

[0110] The lead screw nut is designed as a hollow circular cross-section shaft. For shafts with thin-walled characteristics, the torsional section modulus is calculated using the following formula:

[0111] Among them, W p Torsional section modulus (m) 3 D is the outer diameter (m), and d is the inner diameter (m).

[0112] When a hollow circular cross-section shaft is subjected to torsion, the maximum shear stress at its outer edge conforms to the following formula:

[0113] Where, τ mαx M represents the maximum shear stress (Pa) at the outer edge, and M represents the torque (N·m).

[0114] When M = 500 N·m, and the hollow circular cross-section shaft is designed with D = 4 cm and d = 3 cm, W p ≈8.590cm 3 , τ mαx ≈58.2MPa.

[0115] The allowable normal stress for ductile materials is the yield strength divided by a safety factor (generally 1.5-2). The allowable shear stress is 0.5-0.6 times the allowable normal stress. The yield strength of 45# steel, widely used in machinery, is 353 MPa. Taking a safety factor of 2 and a multiple of 0.5, the allowable shear stress [τ] = 88.25 MPa, which satisfies τ. mαx The requirement of <[τ].

[0116] Other components and operations of the integrated torsion-shear-pull-out testing device according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0117] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0118] Although embodiments of the invention have been shown and described, those skilled in the art will understand 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 claims and their equivalents.

Claims

1. An integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces, characterized in that, The device includes a main body, a torque-shear detection device, and a pull-out detection device. The main body includes a fixed frame, a handwheel, a torque multiplier, a transmission mechanism, and a main shaft. The torque multiplier is mounted on the top surface of the fixed frame. The input shaft of the torque multiplier is connected to the handwheel, and the output shaft of the torque multiplier is connected to the main shaft. The transmission mechanism is connected to the main shaft. The transmission mechanism is used to connect the torsion-shear detection device or the pull-out detection device. When the transmission mechanism and the torsion-shear detection device are connected, the integrated torsion-shear and pull-out detection device is in torsion-shear mode, used to detect the torsion-shear strength between pavement structural layers. The transmission mechanism drives the torsion-shear detection device to rotate synchronously with the main shaft. When the transmission mechanism and the pull-out detection device are connected, the integrated torsion-shear and pull-out detection device is in pull-out mode, used to detect the pull-out strength between pavement structural layers. The transmission mechanism drives the pull-out detection device to move up and down along the main shaft. The transmission mechanism includes a spline nut, a lead screw nut, and a first flange. The spline nut and the lead screw nut are respectively connected to the main shaft for transmission, and the spline nut is located above the lead screw nut. The first flange is installed at the bottom of the lead screw nut and is used to connect the torsion shear detection device or the pull-out detection device. When the first flange is connected to the torsion and shear detection device, the spline nut and the lead screw nut are connected as one unit and rotate synchronously with the main shaft; when the first flange is connected to the pull-out detection device, the spline nut and the lead screw nut are in a separated state, and the lead screw nut moves up and down along the main shaft.

2. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 1, characterized in that, The main shaft is provided with a raceway and a slideway on its outside. The raceway is spirally arranged around the outside of the main shaft, and the slideway is vertically arranged on the outside of the main shaft. The spline nut has a limiting member inside, which matches the slide rail. The limiting member is inserted into the slide rail, so that the spline nut can slide up and down along the main shaft, or the spline nut can rotate synchronously with the main shaft. The steel ball inside the lead screw nut moves along the raceway, causing the lead screw nut to move up and down along the main shaft, or causing the lead screw nut and the main shaft to rotate relative to each other.

3. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 2, characterized in that, The spline nut is a hollow cylindrical structure. The limiting member is provided on the inner surface of the spline nut. The bottom of the spline nut is provided with a locking member A, and the top of the lead screw nut is provided with a locking groove. The locking member and the locking groove are matched. When the first flange is connected to the torsion and shear detection device, the locking member is embedded in the locking groove to connect the spline nut and the lead screw nut.

4. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 2, characterized in that, The spline nut includes a connecting part and a base, the base is installed at the bottom of the connecting part, and the base is sleeved on the outside of the connecting part; The connecting part is a hollow cylindrical structure, and the limiting member is provided on the inner surface of the connecting part; The base has a locking piece B at its bottom and a locking groove at its top. The locking piece and the locking groove match. When the first flange is connected to the torsion and shear detection device, the locking piece is embedded in the locking groove, so that the spline nut and the lead screw nut are connected.

5. A torsion-shear-pull-out integrated testing device for detecting the interlayer bond strength of road surfaces according to claim 3 or 4, characterized in that, The pull-out detection device includes a second flange, a tension sensor, a pull-out rod, and a pull-out disc. The second flange is used to connect to the first flange, and the first flange, the tension sensor, the pull-out rod, and the pull-out disc are connected in sequence.

6. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 5, characterized in that, The mounting frame includes a mounting platform, the torque multiplier is mounted on the top surface of the mounting platform, and the output shaft of the torque multiplier passes through the mounting platform and is connected to the main shaft; The main body also includes two limiting posts, which are respectively installed on the bottom surface of the mounting platform and located on the left and right sides of the transmission mechanism. The limiting post guide groove is vertically provided on the side of the transmission mechanism. The second flange is provided with limiting sliders at its left and right ends respectively. The limiting sliders are matched with the guide groove. After the first flange is connected to the pull-out detection device, the limiting sliders are engaged in the guide groove.

7. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 6, characterized in that, The pull-out detection device also includes a universal joint and a positioning nut. The top end of the universal joint is connected to the second flange, and the bottom end of the universal joint is connected to the tension sensor. The bottom of the tension sensor is provided with a connector, the connector is hollow inside and has an internal thread, the pull rod has an external thread, and the connector and the pull rod are threadedly connected. The positioning nut is sleeved on the outside of the pull rod, and the positioning nut is used to fix the position of the pull rod.

8. The integrated torsion-shear-pull-out testing device for detecting the interlayer bond strength of road surfaces according to claim 7, characterized in that, The bottom end of the pull rod is provided with a limiting ball, the diameter of which is larger than the diameter of the pull rod; The top surface of the drawing disc is provided with a connecting mechanism, which is a cylinder, and the limiting ball is rotatably connected to the connecting mechanism.

9. A torsion-shear-pull-out integrated testing device for detecting the interlayer bond strength of road surfaces according to claim 3 or 4, characterized in that, The torque-shear detection device includes a third flange, a torque sensor, a universal coupling, and a torque-shear disc. The torque sensor is mounted on the third flange, which is used to connect to the first flange. One end of the universal coupling is connected to the torque sensor, and the other end is connected to the torque-shear disc.

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