Bending test device for asphalt concrete test block
By using components such as guide rods, bidirectional scale rods, and scale calibration plates in the asphalt concrete specimen bending test device, the measurement error problem caused by inaccurate specimen positioning was solved, achieving high-precision specimen calibration and simplifying operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2026-04-14
AI Technical Summary
The existing asphalt concrete specimen bending test device has shortcomings in terms of precise specimen positioning and load alignment, resulting in large errors in the test results.
The calibration components include a guide rod, a two-way scale rod, and a scale calibration plate. By sliding the scale calibration plate, the test block is pushed to ensure that the loading force is applied perpendicularly to the center of the test block. Combined with the reverse scale groove and detachable middle plate design, it can adapt to test blocks of different specifications and simplify the operation process.
It improves the accuracy of measurement results, reduces errors caused by off-center loading, adapts to test blocks of different specifications, simplifies the operation process, and expands the application of the device.
Smart Images
Figure CN224122346U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of asphalt concrete test block testing equipment, and in particular relates to an asphalt concrete test block bending test device. Background Technology
[0002] Bending performance testing of asphalt concrete specimens is an important means of evaluating their crack resistance and durability. The relevant testing equipment must meet the requirements of the three-point bending method in standards (such as DL / T5362-2018). In the prior art, bending testing equipment usually consists of a test frame, a load machine, and a specimen support structure, which simulates the actual stress state by applying concentrated loads.
[0003] However, in practice, the accurate positioning of the test block and the alignment of the load remain key factors affecting the test results. In traditional devices, the calibration of the test block often relies on manual visual adjustment or simple limiting blocks, which can easily lead to load eccentricity due to misalignment of the test block, resulting in data deviation. Summary of the Invention
[0004] The purpose of this invention is to address the problems existing in the prior art by providing an asphalt concrete specimen bending test device that can quickly calibrate the position of the asphalt concrete specimen and ensure the accuracy of the bending performance test results.
[0005] To achieve the above objectives, the present invention employs the following technical solution: an asphalt concrete specimen bending test device, comprising a test frame and a load machine assembled at the top of the test frame, wherein a placement platform is provided on the test frame, the center of which is aligned with the load machine, and a calibration component for calibrating the asphalt concrete specimen is provided on the test frame and on one side of the placement platform, the calibration component comprising a middle plate provided on the test frame, the middle plate being located in the same vertical section as the load machine, and a guide rod and a bidirectional scale rod in the same direction as the length of the placement platform provided on the middle plate, wherein slidable scale calibration plates are provided on the guide rod and the bidirectional scale rod on both sides of the middle plate.
[0006] In the above technical solution, by aligning the center of the placement platform with the load machine, the loading force is ensured to act perpendicularly on the center of the asphalt concrete specimen, avoiding measurement errors caused by off-center loading. By setting the center plate at the center of the placement platform along its length, combined with the guide rod, bidirectional scale rod, and scale calibration plate, the asphalt concrete specimen is pushed by sliding the scale calibration plate, thus achieving symmetrical calibration along the length of the asphalt concrete specimen. This further ensures that the loading force acts perpendicularly on the center of the asphalt concrete specimen, effectively improving the accuracy of the measurement results. In addition, the sliding scale calibration plate can be flexibly adjusted according to the size of the specimen to adapt to different specifications of specimens, such as standard small beam specimens or non-standard specimens. The bidirectional scale rod provides an intuitive symmetrical calibration function, simplifying the operation process.
[0007] Optionally, the output end of the load machine is connected to a contact platform, the contact platform includes a docking seat, the lower end of which is integrally formed with a triangular prism, one edge of the lower end of the triangular prism is aligned with the placement platform, and the length of the triangular prism is not less than 90% of the width of the asphalt concrete test block.
[0008] In the above technical solution, the edges of the triangular prism serve as the points of application of line loads, conforming to the asphalt concrete bending test standards (such as the three-point bending method), ensuring that the stress concentration distribution is consistent with the actual working conditions. The length of the triangular prism is consistent with the width of the test block, which can minimize the risk of local crushing or data deviation caused by uneven force application.
[0009] Optionally, the test frame has a central socket for inserting the middle plate, which allows the middle plate to be detached and facilitates the replacement of different functional modules, such as different range scales or calibration tools, thus expanding the uses of the device. In addition, the socket design ensures that the middle plate is accurately positioned in the center of the test frame, avoiding errors caused by manual adjustment.
[0010] Optionally, the bottom end of the middle plate is wrapped with a resistance-increasing sleeve, which is a rubber sleeve. The resistance-increasing sleeve is inserted into the central socket. The rubber sleeve increases the friction and enhances the installation tightness between the middle plate and the test frame, ensuring calibration stability.
[0011] Optionally, the lengths of the guide rod and the bidirectional ruler rod are both greater than the length of the asphalt concrete test block. The surface of the bidirectional ruler rod and both sides of the middle plate are engraved with scale grooves extending from the middle plate toward the end of the bidirectional ruler rod, with the scale grooves on both sides facing opposite directions.
[0012] In the above technical solution, the reverse scale grooves allow for bidirectional symmetrical adjustment of the scale calibration plate position from the center zero point, quickly achieving centering of the test block. For example, when the test block length is 300mm, the scales on both sides are simultaneously adjusted to 150mm. Moreover, the scale grooves are physically engraved, avoiding the problem of blurred readings caused by wear or contamination in traditional scales.
[0013] Optionally, extension tubes are fixedly installed on both sides of the middle plate and on the outer periphery of the guide rod or bidirectional scale rod to increase the contact surface with the guide rod or bidirectional scale rod, making the installation of the middle plate and the guide rod or bidirectional scale rod more stable.
[0014] Optionally, the scale calibration plate has through holes adapted to the guide rod and the bidirectional scale rod. The height of the scale calibration plate is the same as the placement height of the asphalt concrete test block, and the scale calibration plate can contact the end face of the asphalt concrete test block.
[0015] In the above technical solution, the perforation and guide rod / scale rod are precisely matched to ensure that the sliding trajectory of the scale calibration plate is strictly linear, avoiding lateral offset from affecting the calibration accuracy. In addition, the height of the scale calibration plate is level with the test block placement surface, ensuring that the thrust of the scale calibration plate can be directly applied to the end face of the asphalt concrete test block when it moves.
[0016] Compared with the prior art, the beneficial effects of this utility model are: 1. By aligning the center of the placement platform with the load machine, the loading force is ensured to act perpendicularly on the center of the asphalt concrete test block, thus avoiding measurement errors caused by off-center loading. By setting the center plate at the center of the placement platform along its length, combined with the guide rod, bidirectional scale rod, and scale calibration plate, and by sliding the scale calibration plate to push the asphalt concrete specimen, symmetrical calibration along the length of the asphalt concrete specimen can be achieved. This further ensures that the loading force acts perpendicularly to the center of the asphalt concrete specimen, effectively improving the accuracy of the measurement results. 2. The sliding scale calibration plate can be flexibly adjusted according to the size of the specimen to adapt to different specifications of specimens, such as standard small beam specimens or non-standard specimens. The bidirectional scale rod provides an intuitive symmetrical calibration function, simplifying the operation process. 3. The design of the center socket allows the center plate to be disassembled, facilitating the replacement of different functional modules, such as different range scales or calibration tools, expanding the application of the device. In addition, the socket design ensures that the center plate is accurately positioned to the center of the test frame, avoiding manual adjustment errors. 4. The reverse scale grooves allow bidirectional symmetrical adjustment of the scale calibration plate position from the center zero point, quickly achieving specimen centering. For example, when the specimen length is 300mm, the scales on both sides are simultaneously adjusted to 150mm. Moreover, the scale grooves are physically engraved, avoiding the problem of blurred readings caused by wear or contamination in traditional rulers. Attached Figure Description
[0017] Figure 1 A front view schematic diagram of an asphalt concrete specimen block bending test device provided in this embodiment of the present invention;
[0018] Figure 2 A rear three-dimensional schematic diagram of an asphalt concrete specimen block bending test device provided for an embodiment of this utility model;
[0019] Figure 3 This is a three-dimensional schematic diagram of the calibration component of this utility model.
[0020] In the figure: 100, asphalt concrete test block; 1, test frame; 2, placement platform; 3, load machine; 4, contact platform; 5, center socket; 6, calibration piece; 61, middle plate; 611, extension tube; 612, resistance-increasing sleeve; 62, guide rod; 63, bidirectional scale rod; 64, scale calibration plate. Detailed Implementation
[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0022] In the description of this utility model, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.
[0023] like Figure 1 As shown, the specific solution of the embodiment is as follows: an asphalt concrete specimen bending test device includes a test frame 1 and a load machine 3 assembled on the top of the test frame 1. A placement platform 2 is provided on the platform of the test frame 1. The center position of the placement platform 2 is aligned with the load machine 3. A calibration piece 6 for calibrating the asphalt concrete specimen 100 is provided on the test frame 1 and on the back of the placement platform 2.
[0024] like Figure 2-3 As shown, the calibration component 6 includes a middle plate 61 set in the test frame 1. The middle plate 61 is made of 6061-T6 aluminum alloy, which is lightweight and has high bending strength. Its thickness is 15mm, and the surface is anodized to improve wear resistance. The middle plate 61 and the load machine 2 are located in the same vertical section. In this embodiment, it is located at the center of the placement platform 2 along its length. The middle plate 61 is provided with a guide rod 62 and a bidirectional scale rod 63 in the same direction as the length of the placement platform 2. Both the guide rod 62 and the bidirectional scale rod 63 are optical axes with a diameter of 20mm, and the surface is chrome-plated to reduce sliding resistance. The scale accuracy of the bidirectional scale rod 63 is 0.1mm. Sliding scale calibration plates 64 are provided on the guide rod 62 and the bidirectional scale rod 63 on both sides of the middle plate 61.
[0025] In this embodiment, both the test frame 1 and the load machine 3 are commercially available precision electronic universal testing machines of model AG-IC100kN, and the equipment is also equipped with deformation measurement equipment.
[0026] In addition, the asphalt concrete specimen 100 in this embodiment is prepared by first making the asphalt concrete into a plate-shaped specimen according to regulations. The preparation process is carried out by using a flat vibrator with a weight block to vibrate and form the specimen. The weight block weighs 24 kg and the vibration time is 3 min. After the specimen is cooled at room temperature for 24 h, it is demolded and then cut into 250 mm × 40 mm × 35 mm (length × height × width) specimens. It is then cured in a constant temperature water bath at 8℃ for 24 h and a small beam bending test is carried out at a mid-span deformation rate of 1.67 mm / min.
[0027] In this embodiment, by aligning the center of the placement platform 2 with the load cell 3, the loading force is ensured to act perpendicularly on the center of the asphalt concrete specimen 100, avoiding measurement errors caused by off-center loading. By setting the center plate 61 at the center of the placement platform 2 along its length, and combining it with the guide rod 62, the bidirectional scale rod 63, and the scale calibration plate 64, the asphalt concrete specimen 100 is pushed by sliding the scale calibration plate 64, thus achieving symmetrical calibration along the length of the asphalt concrete specimen 100. This further ensures that the loading force acts perpendicularly on the center of the asphalt concrete specimen 100, effectively improving the accuracy of the measurement results. In addition, the sliding scale calibration plate 64 can be flexibly adjusted according to the size of the specimen to adapt to different specifications of specimens, such as standard small beam specimens or non-standard specimens. The bidirectional scale rod 63 provides an intuitive symmetrical calibration function, simplifying the operation process.
[0028] It should be noted that after calibrating the asphalt concrete specimen 100 using the scale calibration plate 64 and the bidirectional scale rod 63, in order to avoid the scale calibration plate 64 affecting the bending test, the scale calibration plate 64 will be slid in the opposite direction so that the scale calibration plate 64 does not come into contact with the asphalt concrete specimen 100.
[0029] In this embodiment, the output end of the load machine 3 is connected to a contact platform 4. The contact platform 4 includes a docking seat, and a triangular prism is integrally formed at the lower end of the docking seat. One edge of the lower end of the triangular prism is aligned with the placement platform 2. After the asphalt concrete test block 100 is placed on the placement platform 2, it is aligned with the asphalt concrete test block 100. The length of the triangular prism is not less than 90% of the width of the asphalt concrete test block 100. Preferably, the length of the triangular prism is the same as the width of the asphalt concrete test block 100.
[0030] It should be noted that the lower edge of the triangular prism is always in the same vertical section as the middle plate 61.
[0031] In this embodiment, the mating seat is made of ductile iron. The triangular prism has an equilateral triangle cross-section with a side length of 20mm and a chamfer radius of 0.3mm to reduce stress concentration. The standard configuration of the triangular prism is 100mm, but customized replacements (such as 80mm, 120mm, etc.) are supported.
[0032] In the above technical solution, the edges of the triangular prism serve as the points of application of line loads, conforming to the asphalt concrete bending test standards, such as the three-point bending method, to ensure that the stress concentration distribution is consistent with the actual working conditions. The length of the triangular prism is consistent with the width of the test block, which can minimize the risk of local crushing or data deviation caused by uneven force application.
[0033] The test frame 1 has a central socket 5 for inserting the middle plate 61, which allows the middle plate 61 to be detached and easy to replace with different functional modules, such as different range scales or calibration tools, thus expanding the use of the device. In addition, the socket design ensures that the middle plate 61 is accurately positioned in the center of the test frame 1, avoiding errors caused by manual adjustment.
[0034] The bottom of the middle plate 61 is wrapped with a resistance-increasing sleeve 612, which is a rubber sleeve. The resistance-increasing sleeve 612 is inserted into the center socket 5. The rubber sleeve increases the friction and strengthens the installation tightness between the middle plate 61 and the test frame 1, ensuring calibration stability.
[0035] The lengths of both the guide rod 62 and the bidirectional ruler rod 63 are greater than the length of the asphalt concrete test block 100. The surface of the bidirectional ruler rod 63 and both sides of the middle plate 61 are engraved with scale grooves extending from the middle plate 61 toward the end of the bidirectional ruler rod 63, with the scale grooves on both sides facing opposite directions.
[0036] In this embodiment, the scale grooves on the surface of the bidirectional scale rod 63 are laser etched to a depth of 0.2 mm and filled with black epoxy resin to improve contrast. The minimum scale interval is 1 mm, and the scale grooves are marked with numbers every 50 mm and filled with fluorescent paint to facilitate reading in dim environments.
[0037] In the above technical solution, the reversed scale grooves allow for bidirectional symmetrical adjustment of the scale calibration plate 64 from the center zero point, quickly centering the test block. For example, when the test block length is 300mm, the scales on both sides are simultaneously adjusted to 150mm. Moreover, the scale grooves are physically engraved, avoiding the problem of blurred readings caused by wear or contamination in traditional scales.
[0038] Extension tubes 611 are fixedly installed on both sides of the middle plate 61 and on the outer periphery of the guide rod 62 or the bidirectional scale rod 63 to increase the contact surface with the guide rod 62 or the bidirectional scale rod 63, so that the middle plate 61 is more securely installed with the guide rod 62 or the bidirectional scale rod 63.
[0039] The scale calibration plate 64 has through holes that are compatible with the guide rod 62 and the bidirectional scale rod 63. The height of the scale calibration plate 64 is the same as the placement height of the asphalt concrete specimen 100, and the scale calibration plate 64 can contact the end face of the asphalt concrete specimen 100.
[0040] In the above technical solution, the perforation and guide rod 62 / scale rod are precisely matched to ensure that the sliding trajectory of the scale calibration plate 64 is strictly linear, avoiding lateral offset from affecting the calibration accuracy. In addition, the height of the scale calibration plate 64 is level with the test block placement surface, ensuring that the thrust of the scale calibration plate 64 can be directly applied to the end face of the asphalt concrete test block 100 when it moves.
[0041] The working principle of the above embodiments:
[0042] Placement and Calibration of Asphalt Concrete Specimen Block 100: Place the asphalt concrete specimen block 100 (standard size 300×100×50mm) on the placement platform 2 and visually align it with the center line. Push the calibration plates 64 on both sides until they lightly touch the end face of the specimen block, and observe whether the scales of the bidirectional scale rod 63 are symmetrical. If the difference in scales on both sides exceeds 2mm, readjustment is required.
[0043] Bending Test: After starting load machine 3, the hydraulic drive system presses down at a uniform rate of 1.67 mm / min at the mid-span deformation rate. The edges of the triangular prism are precisely applied to the mid-span of the specimen to form a three-point bending load. As the load continues to increase, the specimen gradually flexes. The deformation measurement device collects mid-span displacement and strain data in real time through extensometers held on both sides. When the specimen reaches the ultimate bending strength, the system automatically records the failure load value and the corresponding deformation. According to the "Test Procedure for Hydraulic Asphalt Concrete" (DL / T5362-2018), parameters such as bending tensile strain and stiffness modulus are calculated. Throughout the process, the closed-loop control system keeps the loading axis aligned with the calibration center of the specimen to ensure that the data conforms to the mechanical transfer model of the standard single-point concentrated load.
[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A bending test apparatus for asphalt concrete specimens, comprising a test frame and a load cell mounted on top of the test frame, characterized in that: The test frame is equipped with a placement platform, the center of which is aligned with the load machine. A calibration component for calibrating asphalt concrete test blocks is provided on the test frame and on one side of the placement platform. The calibration component includes a middle plate set in the test frame. The middle plate and the load machine are located in the same vertical section. A guide rod and a bidirectional scale rod are provided on the middle plate. Sliding scale calibration plates are provided on both sides of the guide rod and the bidirectional scale rod.
2. The asphalt concrete specimen bending test device according to claim 1, characterized in that: The output end of the load machine is connected to a contact platform. The contact platform includes a docking seat. A triangular prism is integrally formed at the lower end of the docking seat. One edge of the lower end of the triangular prism is aligned with the placement platform. One edge of the lower end of the triangular prism is aligned with the middle plate. The length of the triangular prism is not less than 90% of the width of the asphalt concrete test block.
3. The asphalt concrete specimen bending test device according to claim 1, characterized in that: The test frame has a central insertion port for inserting the middle plate.
4. The asphalt concrete specimen bending test device according to claim 3, characterized in that: The bottom of the middle plate is wrapped with a resistance-increasing sleeve, which is a rubber sleeve, and the resistance-increasing sleeve is inserted into the central socket.
5. The asphalt concrete specimen bending test device according to claim 1, characterized in that: The lengths of the guide rod and the bidirectional ruler rod are both greater than the length of the asphalt concrete test block. The surface of the bidirectional ruler rod and both sides of the middle plate are engraved with scale grooves extending from the middle plate toward the end of the bidirectional ruler rod, with the scale grooves on both sides facing opposite directions.
6. The asphalt concrete specimen bending test device according to claim 1, characterized in that: Extension tubes are fixedly installed on both sides of the middle plate and on the outer periphery of the guide rod or bidirectional ruler rod.
7. The asphalt concrete specimen bending test device according to claim 1, characterized in that: The ruler calibration plate has through holes that are compatible with the guide rod and the bidirectional ruler rod. The height of the ruler calibration plate is the same as the placement height of the asphalt concrete test block, and the ruler calibration plate can contact the end face of the asphalt concrete test block.