Marshall test piece fatigue test loading clamp

Abstract

The utility model discloses a Marshall test piece fatigue test loading clamp which comprises a bottom plate, a bearing plate, two guide plates, an upper pressing strip and a lower pressing strip, the two guide plates are oppositely supported and fixedly connected to the bottom plate, vertical strip holes are formed in the guide plates, the bearing plate is located between the two guide plates, connecting lugs which extend into the strip holes and can slide along the strip holes are arranged on the corresponding sides of the bearing plate, and the upper pressing strip and the lower pressing strip are arranged on the bearing plate. Bolts are screwed on the connecting lugs in a threaded mode. The lower pressing strip is fixedly connected to the upper end of the bottom plate, and the upper pressing strip is fixedly connected to the lower end of the bearing plate. The Marshall test piece fatigue testing device has the advantages of being simple in structure, stable, reliable, capable of effectively improving the efficiency of a Marshall test piece fatigue test, and low in manufacturing and using cost.

Description

Technical Field

[0001] The utility model relates to the technical field of specimen detection equipment, in particular to a Marshall specimen fatigue test loading fixture. Background Art

[0002] Cracks are one of the most common diseases of asphalt pavement, and fatigue network cracks are the main form of asphalt pavement damage. The cracks that appear in the late use of asphalt pavement are related to the bending stress generated by the running vehicles exceeding the bending strength of the material. The generation of fatigue cracks depends on the size of the vehicle bending stress and the number of repeated driving loads. Therefore, cracks can reflect the fatigue characteristics of different materials to a certain extent. According to the requirements of the splitting test of asphalt mixture T0716-2011 in the "Testing Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011), a splitting test fixture is required for testing. my country's utility model patent announcement number CN204718894U discloses a Marshall specimen splitting strength test device, and specifically discloses that it includes a base 6, a lifting platform is installed on the base 6, and a fixture for fixing the specimen is arranged on the lifting platform. The fixture includes an upper bearing plate 3 and a lower bearing plate 5 arranged parallel to the upper bearing plate 3 and the lower bearing plate 5 is movably connected by a positioning rod 4. The upper bearing plate 3 and the lower bearing plate 5 are symmetrically installed with pressure strips 9; a spherical pressure head 8 with a load sensor 7 that can move in a direction close to or away from the upper bearing plate 3 is installed above the upper bearing plate 3. When the device is used, two sets of hydraulic systems are required, that is, one hydraulic system is used to drive the lifting platform to move, and the other is used to drive the upper pressure plate 1 to move and apply load to the specimen. Its structure is relatively complex, and personnel are required to assist in lifting the upper load plate during the installation and removal of the specimen, which is inconvenient to operate. In addition, when applying load to the specimen, two sets of hydraulic systems must be executed sequentially, the process time is relatively long, and the equipment manufacturing and use costs are relatively high. In addition, when the upper pressure system is working, the lower hydraulic system needs to bear pressure and have sufficient stability, so the reliability requirements for the lower hydraulic system are also high. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a loading fixture for a Marshall specimen fatigue test.

[0004] In order to solve the above technical problems, the technical solution of the utility model is:

[0005] A Marshall specimen fatigue test loading fixture comprises a base plate, a pressure plate, two guide plates, an upper pressure strip and a lower pressure strip, wherein the two guide plates are supported and fixedly connected to the base plate, and vertical strip holes are provided on the guide plates. The pressure plate is located between the two guide plates, and corresponding sides are provided with connecting ears which extend into the strip holes and can slide along the strip holes, and bolts are screwed on the connecting ears; the lower pressure strip is fixedly connected to the upper end of the base plate, and the upper pressure strip is fixedly connected to the lower end of the pressure plate.

[0006] Preferably, a channel communicating with the strip hole is disposed on the upper portion of the strip hole, and the channel and the strip hole form a sickle shape or a T shape.

[0007] Preferably, a groove is provided in the middle of the upper end of the pressure plate, and a pressure sensor is provided in the groove; the pressure sensor includes a pressure head adapted to the groove, a sensor body located at the upper end of the pressure head, and a screw located at the upper end of the sensor body.

[0008] Preferably, the lower pressing strip is connected to the bottom plate in a detachable structure.

[0009] Preferably, the upper pressure strip and the pressure plate are connected by a detachable structure.

[0010] The above technical solution has the following advantages:

[0011] The utility model has a simple structure, is stable and reliable, can effectively improve the efficiency of the Marshall specimen fatigue test, and has low manufacturing and use costs. The pressure plate can be locked on the guide plate, so when clamping and removing the specimen, there is no need for personnel to assist in lifting the pressure plate, and the specimen is easy to install and remove quickly, saving manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a front view of the first embodiment of the utility model, wherein the pressure sensor and the groove are in a separated state;

[0013] Figure 2 for Figure 1 A top view of

[0014] Figure 3 for Figure 1 Left view of;

[0015] Figure 4 for Figure 1 Stereoscopic image of

[0016] Figure 5 for Figure 1 A top view of the middle pressure plate;

[0017] Figure 6 This is a schematic diagram of the structure of the guide plate in the second embodiment of the utility model;

[0018] In the figure, 1-bottom plate, 2-pressure plate, 3-guide plate, 4-upper pressure strip, 5-lower pressure strip, 6-hole, 7-connecting ear, 8-bolt, 9-channel, 10-groove, 11-pressure sensor, 12-pressure head, 13-sensor body, 14-screw. DETAILED DESCRIPTION

[0019] The specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these implementation methods is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each implementation method of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] Example 1

[0021] As shown in the accompanying drawings, a Marshall specimen fatigue test loading fixture includes a base plate 1, a pressure plate 2, two guide plates 3, an upper pressure strip 4 and a lower pressure strip 5. The two guide plates 3 are supported and fixedly connected to the base plate 1. A vertical bar hole 6 is opened on the guide plate 3. The pressure plate 2 is located between the two guide plates 3, and a connecting ear 7 extending into the bar hole 6 and slidable along the bar hole 6 is arranged on the corresponding side. Bolts 8 are screwed on the connecting ears 7; the lower pressure strip 5 is fixedly connected to the upper end of the base plate 1, and the upper pressure strip 4 is fixedly connected to the lower end of the pressure plate 2.

[0022] When in use, the pressure plate 2 can be locked on the guide plate 3 by tightening the bolt 8, that is, the end of the connecting ear 7 is retracted to a certain distance from the outer end face of the guide plate 3, and the end of the bolt 8 is frictionally engaged with the adjacent surface of the guide plate by tightening the bolt 8 to achieve the locking and positioning of the pressure plate 2. Therefore, when clamping and disassembling the test piece, there is no need for personnel assistance to assist in lifting the pressure plate 2, and the test piece installation and disassembly is convenient and fast, which saves manpower.

[0023] As a further improved technical solution of this embodiment, a groove 10 is provided in the middle of the upper end of the pressure plate 2, and a pressure sensor 11 is provided in the groove 10; the pressure sensor 11 includes a pressure head 12 adapted to the groove 10, a sensor body 13 located at the upper end of the pressure head 12, and a screw 14 located at the upper end of the sensor body 13. By providing the pressure sensor 11, when in use, the screw 14 is connected to the driving end of the pressure device, and the pressure can be applied by the pressure device, and the pressure information is obtained by the pressure sensor 11 and transmitted to the corresponding display device for display. Obviously, other methods can also be used to measure the pressure, such as using digital imaging equipment to perform a splitting fatigue test on the cut asphalt mixture specimen, taking pictures with a charge coupled device camera (CCD), recording the images of the specimen at different fatigue times, and using digital imaging technology to analyze the displacement field and strain field of the asphalt mixture fatigue specimen.

[0024] As a preferred technical solution of this embodiment, the lower pressure strip 5 is connected to the bottom plate 1 by a detachable structure, and the upper pressure strip 4 is connected to the pressure plate 2 by a detachable structure. The detachable structure can be connected by a common connection form such as bolt connection.

[0025] Example 2

[0026] As shown in the accompanying drawings, a channel 9 communicating with the strip hole 6 is arranged on the upper part thereof, and the channel 9 and the strip hole 6 form a sickle shape, and can obviously also be a T shape, etc. When in use, the connecting ear 7 can be moved into the channel 9, and the channel 9 restricts the connecting ear 7 from moving downward, thereby limiting the height position of the pressure plate 2 and further improving the convenience of operation.

[0027] As a specific technical solution of this embodiment, the material of each component of the fixture of the utility model is preferably alloy high carbon steel. The specimen for the splitting fatigue test is a standard Marshall specimen, which is cut into a cylindrical specimen with a diameter of (φ101.6±0.25) mm and a height of (50±0.5) mm. The following beading includes an upper beading and a lower beading. The cross-sectional shape and size of the beading are: the specimen diameter is (101.6±0.25) mm, the beading width is 12.7 mm, the inner curvature radius is 50.8 mm, and the edges of both ends of the beading are rounded. The length of the beading should be higher than the specimen so that the fixture can be used regardless of the direction of the test. The guide plates on the left and right sides of the fixture serve as guide components of the test loading fixture. Their function is to limit the upper and lower beadings from tilting to the left and right to ensure movement on the plumb line during the test. A vertical hole is opened in the guide plate, with a diameter of 14 mm, which is 1 mm wider than the width of the connecting ears at both ends of the pressure plate.

[0028] The utility model has a simple structure, is stable and reliable, can effectively improve the efficiency of the Marshall specimen fatigue test, and has low manufacturing and use costs.

[0029] The pressure sensor and related digital display equipment involved in the utility model are all existing technologies, which can be fully implemented by those skilled in the art and need not be elaborated. At the same time, the content protected by the utility model does not involve the improvement of software and methods.

[0030] The above is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A Marshall specimen fatigue test loading fixture, comprising a base plate (1), a pressure plate (2), two guide plates (3), an upper pressure strip (4) and a lower pressure strip (5), characterized in that: The two guide plates (3) are supported and fixedly connected to the bottom plate (1); a vertical strip hole (6) is opened on the guide plate (3); the pressure plate (2) is located between the two guide plates (3), and a connecting ear (7) is provided on the corresponding side, which extends into the strip hole (6) and can slide along the strip hole (6); bolts (8) are screwed on the connecting ears (7); the lower pressure strip (5) is fixedly connected to the upper end of the bottom plate (1), and the upper pressure strip (4) is fixedly connected to the lower end of the pressure plate (2).

2. The Marshall specimen fatigue test loading fixture according to claim 1, characterized in that: A channel (9) communicating with the strip hole (6) is arranged on the upper part thereof, and the channel (9) and the strip hole (6) form a sickle shape or a T-shape.

3. The Marshall specimen fatigue test loading fixture according to claim 1 or 2, characterized in that: A groove (10) is provided in the middle of the upper end of the pressure plate (2), and a pressure sensor (11) is provided in the groove (10); the pressure sensor (11) comprises a pressure head (12) adapted to the groove (10), a sensor body (13) located at the upper end of the pressure head (12), and a screw (14) located at the upper end of the sensor body (13).

4. The Marshall specimen fatigue test loading fixture according to claim 1 or 2, characterized in that: The lower pressing strip (5) is connected to the bottom plate (1) in a detachable structure.

5. The Marshall specimen fatigue test loading fixture according to claim 3, characterized in that: The lower pressing strip (5) is connected to the bottom plate (1) in a detachable structure.

6. The Marshall specimen fatigue test loading fixture according to claim 1 or 2, characterized in that: The upper pressure strip (4) and the pressure bearing plate (2) are connected by a detachable structure.

7. The Marshall specimen fatigue test loading fixture according to claim 3, characterized in that: The upper pressure strip (4) and the pressure bearing plate (2) are connected by a detachable structure.

8. The Marshall specimen fatigue test loading fixture according to claim 4, characterized in that: The upper pressure strip (4) and the pressure bearing plate (2) are connected by a detachable structure.

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