Shearing test device for simulating semi-rigid base and concrete pavement in gobi environment

Abstract

The utility model provides a shear test device for simulating a semi-rigid base and a concrete pavement in a gobi environment, and belongs to the technical field of pavement shear simulation devices. In order to solve the problem that the shearing resistance between a semi-rigid base layer and a cement concrete surface layer in the gobi environment does not exist at present, a test piece clamping mechanism, a gravity loading mechanism, a thrust loading mechanism, a heating mechanism, an ash adding mechanism and an ash removing mechanism are arranged in a box body; the gravity loading mechanism and the thrust loading mechanism are used for simulating the gravity load and the interlayer shearing force of the road surface respectively, the heating mechanism and the ash adding mechanism are used for simulating the high temperature and sand environment of the gobi in the box body, then the shearing resistance of the road surface in the gobi environment is obtained, and early cracking of a semi-rigid base layer in the gobi environment is effectively reduced. The service life of the pavement is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of pavement shear resistance simulation devices, in particular to a shear resistance test device for a semi-rigid base and a concrete pavement under a simulated Gobi environment. Background Art

[0002] In recent years, the continuous development of the highway network has brought great convenience to transportation services. However, due to the adverse effects of harsh environmental conditions and the differences in the materials of each pavement structure layer, the bonding between the various pavement structures has been greatly weakened, and the base layer and the surface layer have become the weakest link in the pavement structure. Especially in the Gobi region in northwest my country, cement concrete surface layer and semi-rigid base layer are widely used to pave roads. However, due to the large temperature difference between day and night, low air humidity and strong winds in the Gobi environment, concrete shrinkage will be aggravated, resulting in poor bonding between the surface layer and the base layer, increasing the risk of concrete cracking, and ultimately reducing the shear resistance between the surface layer and the base layer.

[0003] At present, the interlayer adhesion of highways is evaluated in China by shear resistance, but the mechanical indicators of the shear resistance between cement concrete surface layer and semi-rigid base layer are rarely involved; for example, the Chinese patent with patent number CN203572725U and the name of a pavement structure interlayer interface shear strength test device includes a shear instrument and a stress loading device, the shear instrument is provided with a push ring and a clamp ring, the stress loading device includes a frame, a sliding device and an actuator, which can generate thrust to the test sample through the push ring and the actuator to test the interlayer interface shear strength test.

[0004] However, the device disclosed in the above-mentioned prior art is for testing samples of conventional road pavement, and cannot be applied to samples in harsh environments such as the Gobi Desert. Currently, there is no related device that can simulate the shear resistance between the semi-rigid base and the cement concrete surface layer in the Gobi Desert. Based on this, it is particularly important to use a simple and effective testing device to measure the interlayer shear resistance of the cement concrete surface layer and the semi-rigid base in the Gobi Desert. Utility Model Content

[0005] In view of the deficiencies in the above-mentioned prior art, the utility model proposes a shear test device for a semi-rigid base and a concrete pavement in a simulated Gobi environment to solve the problems in the above-mentioned background technology.

[0006] The technical solution adopted by the utility model is as follows:

[0007] The shear test device for semi-rigid base and concrete pavement under simulated Gobi environment includes a box body, and a

[0008] The specimen clamping mechanism is arranged at the bottom of the box;

[0009] A gravity loading mechanism is arranged on the top of the box and located above the specimen clamping mechanism, and is used to simulate the gravity load of the road surface;

[0010] The thrust loading mechanism is arranged at the bottom of the box and located on the right side of the specimen clamping mechanism, and is used to simulate the interlayer shear force of the pavement;

[0011] A heating mechanism is arranged on the inner wall of the top of the box body;

[0012] A dust adding mechanism and a dust cleaning mechanism are respectively arranged on both sides of the exterior of the box body.

[0013] In order to achieve the above purpose, further, the ash adding mechanism includes a feeding port and a blower, the feeding port and the blower are both connected to the side wall of the box body, and the feeding port is located above the blower.

[0014] Furthermore, the dust cleaning mechanism includes a vacuum cleaner and an air outlet, and the vacuum cleaner and the air outlet are both connected to the side wall of the box body.

[0015] A further preferred embodiment of the above scheme is: the specimen clamping mechanism includes a fixed clamp, a movable clamp and a specimen, the fixed clamp is fixedly connected to the bottom of the box, the movable clamp is placed above the fixed clamp, a displacement rate sensor is provided on the top of the movable clamp, and the specimen is inserted in the middle of the fixed clamp and the movable clamp.

[0016] By adopting the above scheme, further, the gravity loading mechanism is a jack, the upper end of the jack is fixedly connected to the inner wall of the top of the box, and the bottom of the jack is connected to a dynamometer, and the longitudinal force of the jack acting on the test piece is measured by the dynamometer.

[0017] By adopting the above solution, further, the thrust loading mechanism is a horizontal loader, the horizontal loader is connected to a stress sensor, and the lateral force acting on the movable clamp is measured by the stress sensor.

[0018] A further preferred embodiment of the above scheme is as follows: a limiting mechanism is further provided in the box body, the limiting mechanism is connected to the left side wall of the box body and is provided corresponding to the movable clamp.

[0019] A further preferred embodiment of the above scheme is as follows: an air switch is arranged on the top outside the box body, and the air switch is electrically connected to the displacement rate sensor.

[0020] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0021] 1. By setting a jack in the vertical direction of the test piece to simulate the vertical load of the road surface, setting a horizontal loader in the horizontal direction to simulate the interlayer shear force of the road surface, and setting a heating mechanism inside the box to simulate the high temperature environment of the Gobi Desert, the feeding port opened on one side of the box can add different sands needed to be simulated in the test into the box, thereby meeting the shear performance test of the road surface in the wind and sand environment of different Gobi areas, providing a reference and theoretical basis for effectively testing the interlayer shear performance of the semi-rigid base and cement concrete pavement in the Gobi environment, thereby improving the adhesion between the surface layer and the base layer and the interlayer shear strength, which is of great significance to effectively reduce the early cracking of the semi-rigid base in the Gobi environment and extend the service life of the road surface.

[0022] 2. By installing a vacuum cleaner and an air outlet on the other side of the box, the sand and stone particles inside the box can be effectively cleaned after the test to prevent sand and stone particles and other impurity particles from remaining in the box.

[0023] 3. The movable clamp of the utility model adopts a two-half spliced ​​structure, which can effectively clamp the test piece and ensure the accuracy of the test results. The movable clamp is fixed with a displacement rate sensor, which can quickly sense the damage of the test piece in the clamp and synchronously close the air switch, saving the operating procedures to a great extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the utility model, the drawings required in the embodiments are briefly introduced below. The drawings described below are only part of the embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of the shear test device of the utility model for semi-rigid base and concrete pavement in a simulated Gobi environment;

[0026] Figure 2 It is a schematic diagram of one side of the overall structure of the utility model;

[0027] Figure 3 It is a schematic diagram of another side of the overall structure of the utility model;

[0028] Figure 4 It is an internal cross-sectional plan view of the utility model;

[0029] Figure 5 It is an internal cutaway stereogram of the utility model;

[0030] Figure 6 It is a three-dimensional diagram of the internal cross-sectional structure of the utility model (a fastener);

[0031] Figure 7It is a three-dimensional diagram of the internal cross-sectional structure of the utility model (another fastener);

[0032] Figure 8 It is a schematic diagram of the structure of the test piece of the utility model;

[0033] In the figure: 1. Box; 2. Specimen clamping assembly; 21. Fixed fixture; 22. Movable fixture; 221. Square block; 23. Specimen; 3. Ash adding mechanism; 31. Feeding port; 32. Blower; 4. Ash cleaning mechanism; 41. Vacuum cleaner; 42. Air outlet; 5. Displacement rate sensor; 6. Jack; 7. Dynamometer; 8. Horizontal loader; 9. Stress sensor; 10. Air switch; 11. Horizontal slide rail; 12. Heating mechanism; 13. Fastener. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present utility model will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments. Example 1

[0035] Reference Figure 1-8 The utility model is a shear test device for a semi-rigid base and a concrete pavement in a simulated Gobi environment, comprising a box body 1, a box cover is hinged on the top of the box body 1, and the internal equipment can be debugged by opening the box cover. In order to facilitate the overall movement of the box body 1, a universal wheel (not shown in the drawings) is connected to the bottom of the box body 1. A specimen clamping mechanism 2, a gravity loading mechanism, a thrust loading mechanism and a heating mechanism 12 are arranged inside the box body 1. The specimen clamping mechanism 2 is connected to the bottom of the box body 1, and the gravity loading mechanism is connected to the top of the box body 1 and is located above the specimen clamping mechanism 2. The box body 1 is connected to the bottom and is located on the right side of the specimen clamping mechanism 2, which is used to simulate the interlayer shear force of the road surface. The heating mechanism 12 is connected to the inner wall at the top of the box body 1, which is used to simulate the high temperature environment of the Gobi Desert. In order to simulate the sandstorm environment of the Gobi Desert and prevent the sandstorm from remaining in the box body, a dust adding mechanism 3 and a dust cleaning mechanism 4 are respectively provided on both sides of the outside of the box body 1. Sand is added to the inside of the box body 1 through the dust adding mechanism 3. After the test, the sand inside the box body 1 is cleaned through the dust cleaning mechanism 4.

[0036] Specifically, Figure 2-3The dust adding mechanism 3 includes a feeding port 31 and a blower 32, both of which are connected to the left side wall of the box 1, and the feeding port 31 is located above the blower 32. Sand is added to the box 1 through the feeding port 31, and then the sand entering the box 1 is blown away by the blower 32 to simulate the Gobi sandstorm environment; the dust cleaning mechanism 4 includes a vacuum cleaner 41 and an air outlet 42, both of which are connected to the right side wall of the box 1. When the test is finished, the vacuum cleaner 41 is turned on to suck out and clean the sand inside the box 1. Here, the blower 32 and the vacuum cleaner 41 are respectively connected to an external power supply.

[0037] In this embodiment, the specimen clamping mechanism 2 includes a fixed clamp 21, a movable clamp 22 and a specimen 23. The fixed clamp 21 is fixedly connected to the bottom of the box body 1, the movable clamp 22 is placed above the fixed clamp 21, and the specimen 23 is inserted in the middle of the fixed clamp 21 and the movable clamp 22; specifically, the fixed clamp 21 is a rectangular or cube structure with a cylindrical hole in the middle, and the movable clamp 22 is composed of two identical square blocks 221 that are half the size of the fixed clamp. A through hole is opened in the middle of the movable clamp 22. When the movable clamp 22 is completely assembled, the through hole is equal to the cylindrical hole in size and corresponds in position.

[0038] Furthermore, in order to make the two square blocks 221 of the movable clamp 22 cooperate with each other, a fastener 13 is installed on the movable clamp 22, such as Figure 6-7 As shown in the figure, there are two specific structures of the fastener 13, namely, the fastener 13 is Figure 7 The vertical fixing form in Figure 6 The adjustable lateral fixing form is of course not limited to the above two structures, and can also be other forms that can achieve the same purpose.

[0039] like Figure 8 As shown, the specimen 23 is a two-layer cylindrical structure. The specimen 23 is randomly cored from the road surface to be tested or formed in a laboratory. The upper layer of the specimen 23 is a concrete surface layer, and the lower layer is a semi-rigid base layer. The diameter of the specimen 23 is compatible with the cylindrical hole and the through hole.

[0040] In this embodiment, the gravity loading mechanism is a jack 6, the upper end of the jack 6 is fixedly connected to the inner wall of the top of the box body 1, and a dynamometer 7 is connected to the bottom of the jack 6. The jack 6, the dynamometer 7 and the test piece 23 are located in a vertical line. The stroke of the jack 6 is adjusted to meet the requirements of the simulated road gravity load, and the longitudinal force of the jack 6 acting on the test piece 23 is measured by the dynamometer 7.

[0041] In this embodiment, the thrust loading mechanism is a horizontal loader 8, and a stress sensor 9 is connected to the output end of the horizontal loader 8. When the horizontal loader 8 acts on the movable clamp 22 to perform a shear test, the lateral force acting on the movable clamp 22 is measured by the stress sensor 9.

[0042] In this embodiment, the heating mechanism 12 is a thermistor, and the thermistor 12 is electrically connected to an external power source. The thermistor here adopts the existing technology, and no improvement is made to the thermistor.

[0043] In order to make the movable clamp 22 move linearly to the left under the thrust of the horizontal loader 8, thereby effectively simulating the interlayer shear force, a limiting mechanism 13 is also arranged in the box body 1. Specifically, the limiting mechanism 13 is two L-shaped limiting plates arranged corresponding to the movable clamp 22. When the movable clamp 22 is pushed, it can move within the range of the two L-shaped limiting plates; at the same time, a displacement rate sensor 5 is fixedly connected to the top of the movable clamp 22, and an air switch 10 is arranged on the top outside the box body 1. When the specimen 23 is damaged, the displacement rate sensor 5 can sense the speed change of the specimen 23 at the moment of damage, and the air switch 10 will be automatically closed at this time.

[0044] In this embodiment, the control ends of the thermistor, jack 6, horizontal loader 8 and stress sensor 9 are all integrated and connected at the air switch 10. That is to say, through one-key operation of the air switch 10, the synchronous opening or synchronous closing of the above-mentioned components can be achieved; in addition, the air switch 10 is electrically connected to the displacement rate sensor 5. When the speed of the displacement rate sensor 5 changes suddenly, the air switch 10 can be automatically closed. Example 2

[0045] The working principle of the shear test device of the utility model for semi-rigid base and concrete pavement in a simulated Gobi environment is as follows:

[0046] First, open the box cover, put the test piece 23 into the fixed fixture 21 and the movable fixture 22, adjust the position of the test piece 23 so that the concrete surface layer of the test piece 23 and the semi-rigid base layer are just in the gap between the fixed fixture 21 and the movable fixture 22, and fix the movable fixture 22 with the fastener 13;

[0047] Then, after closing the box cover, the air switch 10 is turned on. At the same time, sand is added to the inside of the box body 1 from the feeding port 31 and the blower 32 is turned on synchronously, so as to achieve the effect of simulating the Gobi sandstorm environment inside the box body 1; after starting work, pay attention to observe the changes of the test piece 23. When the test piece 23 is damaged, the displacement rate sensor 5 can sense the speed change of the test piece 23 at the moment of damage, and the air switch 10 will be automatically turned off at this time, and the jack 6, the horizontal loader 8, etc. will stop working synchronously;

[0048] Finally, the operator reads the readings of the dynamometer 7 and the stress sensor 9 to obtain the data of the breaking load, and calculates the shear strength. After the test is completed, the vacuum cleaner 41 is turned on to clean the sand inside the box 1.

[0049] It should be clear that the above detailed description of the embodiments of the utility model provided in the accompanying drawings is only used to further illustrate the utility model, and is not intended to limit the scope of the utility model claimed for protection, but only represents selected embodiments of the utility model. Based on the embodiments of the utility model, some non-essential improvements and adjustments made by ordinary technicians in this field according to the above content of the utility model belong to the protection scope of the utility model.

Claims

1. A shear test device for a semi-rigid base and a concrete pavement in a simulated Gobi environment, comprising a box (1), characterized in that: The box (1) is provided with: A specimen clamping mechanism (2) is arranged at the bottom of the box (1); A gravity loading mechanism, arranged on the top of the box (1) and located above the specimen clamping mechanism (2), and used to simulate the gravity load of the road surface; A thrust loading mechanism, arranged at the bottom of the box (1) and located on the right side of the specimen clamping mechanism (2), and used to simulate the interlayer shear force of the road surface; A heating mechanism (12) is arranged on the inner wall of the top of the box body (1); A dust adding mechanism (3) and a dust cleaning mechanism (4) are respectively provided on both sides of the exterior of the box body (1).

2. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 1 is characterized in that: The ash adding mechanism (3) comprises a feeding port (31) and a blower (32), and the feeding port (31) and the blower (32) are both connected to the side wall of the box body (1).

3. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 2 is characterized in that: The dust cleaning mechanism (4) comprises a dust collector (41) and an air outlet (42), and the dust collector (41) and the air outlet (42) are both connected to the side wall of the box body (1).

4. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 1 is characterized in that: The specimen clamping mechanism (2) comprises a fixed clamp (21), a movable clamp (22) and a specimen (23); the fixed clamp (21) is fixedly connected to the bottom of the box (1); the movable clamp (22) is placed above the fixed clamp (21); a displacement rate sensor (5) is arranged on the movable clamp (22); and the specimen (23) is inserted in the middle of the fixed clamp (21) and the movable clamp (22).

5. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 4 is characterized in that: The gravity loading mechanism is a jack (6), which is fixedly connected to the inner wall of the top of the box (1), and its bottom is connected to a dynamometer (7), and the longitudinal force of the jack (6) acting on the test piece (23) is measured by the dynamometer (7).

6. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 5 is characterized in that: The thrust loading mechanism is a horizontal loader (8), and a stress sensor (9) is connected to the horizontal loader (8). The lateral force acting on the movable clamp (22) is measured by the stress sensor (9).

7. The shear test device for semi-rigid base and concrete pavement in a simulated Gobi environment according to claim 6, characterized in that: An air switch (10) is arranged outside the box body (1), and the air switch (10) is electrically connected to the displacement rate sensor (5).

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