A clamping device for low-temperature semi-circular bending test of asphalt mixture.

Abstract

This utility model relates to the field of asphalt testing technology, and more particularly to a clamping device for low-temperature semi-circular bending tests of asphalt mixtures, comprising a base, a clamping device, and positioning pins; the clamping device includes a fixed-end clamping plate, a movable-end clamping plate, clamping rails, and an elastic element; the base is provided with two parallel clamping rails, one end of each clamping rail being a fixed end, and a sliding block slidably connected to each clamping rail; the elastic element connects the sliding block to the fixed end, and the elastic element can drive the sliding block to slide towards the fixed end; the fixed-end clamping plate is connected between the two fixed ends, and the movable-end clamping plate is connected between the two sliding blocks; positioning pins are provided at the center of both the fixed-end clamping plate and the movable-end clamping plate; and support members are provided on both sides of the clamping device. This utility model can adjust the clamping thickness according to the size of the specimen, and can test a wider range of clamping thicknesses.

Description

Technical Field

[0001] This utility model relates to the field of asphalt testing technology, and in particular to a clamping device for low-temperature semi-circular bending tests of asphalt mixtures. Background Technology

[0002] The low-temperature semi-circular bending test of asphalt mixtures is suitable for determining the fracture toughness of asphalt mixtures to evaluate their low-temperature crack resistance. The test uses a semi-circular asphalt mixture specimen. A load is applied along the vertical diameter of the specimen, and the load-displacement curve is measured. The fracture energy, stiffness, and fracture toughness are calculated from the load-displacement curve to evaluate the low-temperature fracture toughness of the asphalt mixture. However, the standard test fixture can only test semi-circular asphalt mixture specimens with a thickness of 25 mm and cannot hold specimens with a thickness of 25-50 mm. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a clamping device for low-temperature semi-circular bending tests of asphalt mixtures, which can adjust the clamping thickness according to the size of the specimen, and can test a wider range of clamping thicknesses.

[0004] To address the aforementioned problems, this utility model proposes a clamping device for a low-temperature semi-circular bending test of asphalt mixtures, comprising a base, a clamping device, and a positioning pin. The clamping device includes a fixed-end clamping plate, a movable-end clamping plate, clamping rails, and an elastic element. The base has two parallel clamping rails, one end of which is a fixed end. A sliding block is slidably connected to each clamping rail, and the elastic element connects the sliding block to the fixed end. The elastic element drives the sliding block to slide towards the fixed end. The fixed-end clamping plate connects between the two fixed ends, and the movable-end clamping plate connects between the two sliding blocks. Positioning pins are located at the center of both the fixed-end clamping plate and the movable-end clamping plate. Supporting elements are located on both sides of the clamping device.

[0005] As an improvement to the above technical solution, it also includes cutting edges, which are disposed opposite each other on the bottom sides of the specimen, and the cross-sectional area of ​​the cutting edges gradually decreases from the top to the bottom; Both the fixed-end clamping plate and the movable-end clamping plate are provided with corresponding clearance openings.

[0006] As an improvement to the above technical solution, the base is provided with a clearance groove, which is connected to the clearance opening.

[0007] As an improvement to the above technical solution, the ratio of the depth of the clearance groove to the distance from the top of the clearance opening to the bottom of the clearance groove is 1:1.5 to 1:1.8.

[0008] As an improvement to the above technical solution, the clamping track is a sliding guide rail, the elastic element is a spring element, the spring element is sleeved on the clamping track, one end of the spring element is fixedly connected to the fixed end, and the other end is fixedly connected to the sliding block.

[0009] As an improvement to the above technical solution, the base is provided with a connection positioning point below the clamping device; the support member is a roller, and tension springs are connected to both ends of the roller shaft. The tension springs are also connected to the connection positioning point, and the tension springs can drive the support member to approach the clamping device.

[0010] As an improvement to the above technical solution, the ratio of the diameter of the support member to the distance from the positioning pin to the base surface is 1:1.5 to 1:1.9.

[0011] The following are the beneficial effects of implementing this utility model: This utility model discloses a clamping device for low-temperature semi-circular bending tests, comprising a base, a clamping mechanism, and positioning pins. The clamping mechanism includes a fixed-end clamping plate, a movable-end clamping plate, a clamping track, and a spring component. A sliding block is slidably connected to the clamping track. The fixed end of the clamping track has a fixed-end clamping plate, and the movable-end clamping plate is mounted on the sliding block. A spring component connects the sliding block and the fixed end. First, because the movable-end clamping plate can move closer to or further away from the clamping track, it can accommodate specimens of different thicknesses, overcoming the size limitations of standard clamps. Second, the spring component provides a self-locking function, simplifying the specimen installation process and effectively improving clamping efficiency. Finally, positioning pins are located at the center of both the fixed-end and movable-end clamping plates, ensuring accurate specimen installation. Attached Figure Description

[0012] Figure 1 This is a front view of a clamping device according to an embodiment of the present invention; Figure 2 This is a top view of a clamping device according to an embodiment of the present invention; Figure 3 This is a perspective view of the test specimen of an embodiment of this utility model. Detailed Implementation

[0013] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0014] See Figures 1 to 3 As shown, this utility model embodiment provides a clamping device for a low-temperature semi-circular bending test of asphalt mixture, including a base 1, a clamping device 2, and a positioning pin 3.

[0015] This utility model embodiment improves the clamping device of the clamping device, enabling it to adjust the clamping thickness according to the specifications of the specimen.

[0016] Specifically, the clamping device 2 includes a fixed-end clamping plate 21, a movable-end clamping plate 22, clamping rails 23, and an elastic element 24. The base 1 has two parallel clamping rails 23, one end of which is a fixed end 25. A sliding block 26 is slidably connected to each clamping rail 23. The elastic element 24 connects the sliding block 26 to the fixed end 25, and can drive the sliding block 26 to slide towards the fixed end 25. The fixed-end clamping plate 21 connects between the two fixed ends 25, and the movable-end clamping plate 22 connects between the two sliding blocks 26. Positioning pins 3 are provided at the center of both the fixed-end clamping plate 21 and the movable-end clamping plate 22. Supporting elements 4 are provided on both sides of the clamping device 2.

[0017] The clamping device of this utility model is used for low-temperature semi-circular bending tests. It includes a base 1, a clamping device 2, and positioning pins 3. The clamping device 2 includes a fixed-end clamping plate 21, a movable-end clamping plate 22, a clamping track 23, and an elastic element 24. A sliding block 26 is slidably connected to the clamping track 23. The fixed end of the clamping track 23 is provided with the fixed-end clamping plate 21, and the movable-end clamping plate 22 is provided on the sliding block 26. An elastic element 24 connects the sliding block 26 and the fixed end 21. First, since the movable-end clamping plate 22 can move closer to or further away from the clamping track 23, it can accommodate specimens of different thicknesses, making up for the size limitations of standard clamps. Second, the elastic element 24 enables the clamping device to have a self-locking function, simplifying the specimen installation process and effectively improving clamping efficiency. Finally, positioning pins 3 are provided at the center of both the fixed-end clamping plate 21 and the movable-end clamping plate 22, so that the specimen 1' can be accurately installed.

[0018] In some embodiments, the specimen 1' is further provided with cutting edges 5, which are disposed opposite to each other on the bottom sides of the specimen 1', and the cross-sectional area of ​​the cutting edges 5 gradually decreases from the top to the bottom. Both the fixed end clamping plate 21 and the movable end clamping plate 22 are provided with corresponding clearance openings 27.

[0019] The cutting edge 6 is positioned on both sides of the bottom of the specimen, directly contacting the fracture initiation area, which facilitates the capture of displacement data in the early stages of crack propagation. Secondly, the cross-sectional area of ​​the cutting edge 5 gradually decreases from top to bottom, forming a barbed structure to ensure the CMOD crack gauge is securely installed and to prevent the sensor from falling off during the test.

[0020] Preferably, the base 1 is provided with a clearance groove 11, which connects with the clearance opening 27. The clearance groove 11 is for facilitating the installation and removal of the sensor at the bottom of the specimen 1'.

[0021] Ideally, the ratio of the depth of the clearance groove 11 to the distance from the top of the clearance opening 27 to the bottom of the clearance groove 11 is 1:1.5 to 1:1.8. Examples include 1:1.5, 1:1.6, and 1:1.8, but it is not limited to these.

[0022] In some embodiments, the clamping track 23 is a sliding rod type guide rail, and the elastic element 24 is a spring element. The spring element 24 is sleeved on the clamping track 23, with one end of the spring element 24 fixedly connected to the fixed end 21 and the other end fixedly connected to the sliding block 22. First, the spring element 24 is sleeved on the sliding rod type guide rail. The linear constraint of the sliding rod type guide rail ensures that the sliding block moves along a fixed trajectory when the spring element 24 is compressed or rebounds, avoiding uneven clamping force caused by skewness. Second, the nested design of the spring element 24 and the clamping guide rail 23 forms an integrated motion unit. During the test, when the load fluctuates, the elastic deformation of the spring element 24 is transmitted to the sliding block 26 through the sliding rod type guide rail, reducing the instantaneous displacement error of the specimen 1'.

[0023] In some embodiments, the base 1 is provided with a connection positioning point 12 below the clamping device 2; the support member 4 is a roller, and both ends of the roller shaft 41 of the roller 4 are connected to tension springs 42, and the tension springs 42 are also connected to the connection positioning point 12. The tension springs 42 can drive the support member 4 to approach the clamping device 2.

[0024] It should be noted that a polytetrafluoroethylene plastic sheet is placed on the roller 4 to ensure that cracking is not affected by friction between the specimen 1' and the roller.

[0025] The roller 4 is used to support the bottom of the specimen 1', allowing the specimen 1' to roll freely along the surface of the roller 4 during loading, eliminating the frictional constraint of the traditional fixed support on the specimen 1', and ensuring that the load is completely converted into pure bending deformation of the specimen 1'. The tension spring 42 is connected at both ends to the shaft column 41 of the roller 4 and the connection positioning point 12 of the base 1, respectively. The elastic rebound force of the tension spring 42 continuously pulls the roller 4 to move towards the clamping device 2, ensuring that the roller 4 is always in close contact with the bottom surface of the specimen 1', eliminating the gap caused by the deformation of the specimen 1'.

[0026] Preferably, the ratio of the diameter of the support member 4 to the distance from the positioning pin 3 to the surface of the base 1 is 1:1.5 to 1:1.9. Examples include 1:1.5, 1:1.7, and 1:1.9, but it is not limited to these.

[0027] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A fixture apparatus for low temperature semi-circular bending test of asphalt mixture, characterized in that, Includes a base, clamping device, and positioning pins; The clamping device includes a fixed-end clamping plate, a movable-end clamping plate, clamping rails, and an elastic element. The base has two parallel clamping rails, one end of which is a fixed end. A sliding block is slidably connected to each clamping rail, and the elastic element connects the sliding block to the fixed end. The elastic element drives the sliding block to slide towards the fixed end. The fixed-end clamping plate connects between the two fixed ends, and the movable-end clamping plate connects between the two sliding blocks. Positioning pins are located at the center of both the fixed-end clamping plate and the movable-end clamping plate. Supporting elements are located on both sides of the clamping device.

2. The clamping device as described in claim 1, characterized in that, It also includes cutting edges, which are positioned opposite each other on the bottom sides of the specimen, and the cross-sectional area of ​​the cutting edges gradually decreases from the top to the bottom; Both the fixed-end clamping plate and the movable-end clamping plate are provided with corresponding clearance openings.

3. The clamping device as described in claim 2, characterized in that, The base is provided with a clearance groove, which is connected to the clearance opening.

4. The clamping device as described in claim 3, characterized in that, The ratio of the depth of the clearance groove to the distance from the top of the clearance opening to the bottom of the clearance groove is 1:1.5 to 1:1.

8.

5. The clamping device as described in claim 1, characterized in that, The clamping track is a sliding guide rail, and the elastic element is a spring. The spring is sleeved on the clamping track, with one end of the spring fixedly connected to the fixed end and the other end fixedly connected to the sliding block.

6. The clamping device as claimed in claim 1, characterized in that, The base has a connection positioning point below the clamping device; the support is a roller, and tension springs are connected to both ends of the roller shaft. The tension springs are also connected to the connection positioning point, and the tension springs can drive the support to approach the clamping device.

7. The clamping device as described in claim 6, characterized in that, The ratio of the diameter of the support member to the distance from the positioning pin to the base surface is 1:1.5 to 1:1.9.

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