CN107796714A - Simulate the asphalt mixture shearing strength tester of actual wheel load - Google Patents

Abstract

The invention relates to an asphalt mixture shear strength tester for simulating the actual wheel load, which comprises an environment box equipped with a heating device, a loading wheel and a test mold cap are arranged in the environment box, and the loading wheel is connected by a connecting rod for The first power device that drives the loading wheel to apply pressure to the test piece and move back and forth in the horizontal direction. The loading wheel is located above the test mold cap; a temperature sensor is installed in the environmental box, and a displacement sensor and a force sensor are installed on the connecting rod. Sensors, displacement sensors and force sensors are all connected to the control panel. The invention can adjust the different ambient temperatures required in the experiment, can simulate the actual wheel load, and conduct the shear strength test of the asphalt mixture. The invention can test the anti-shear strength of the asphalt mixture under the conditions of effectively simulating the actual environment temperature and the dynamic load of the road surface, which is consistent with the actual situation and has high accuracy.

Description

Asphalt Mixture Shear Strength Tester Simulating Actual Wheel Loads

technical field

The invention belongs to the technical field of asphalt mixture shear strength equipment and relates to an asphalt mixture shear strength tester for simulating actual wheel loads.

Background technique

In recent years, my country's highway industry has developed rapidly and made great achievements. At present, semi-rigid asphalt pavement structure is commonly used in my country's high-grade highways. This pavement structure has made important contributions to the construction and development of high-grade highways suitable for heavy-duty traffic in my country. However, semi-rigid base asphalt pavement generally has early failure phenomena, and scholars at home and abroad have conducted a lot of investigations on this. Studies have shown that interlayer shear failure is one of the key factors causing pavement damage. Interlayer shear leading to interlayer slip will seriously degrade the service level of the road and seriously shorten the service life of the road. As a temperature-sensitive material, asphalt mixture is closely related to the ambient temperature. Therefore, there is an urgent need for a device that can measure the shear resistance of asphalt mixtures at different temperatures in order to better reflect the shear resistance of asphalt mixture layers.

Asphalt mixture shear strength tester is an indispensable equipment for measuring the shear strength of asphalt mixture, which is convenient and quick.

At present, the asphalt mixture shear strength tester has the following disadvantages:

1. When applying lateral pressure to the specimen, the static loading method is adopted, which is inconsistent with the actual situation;

2. Regardless of the influence of temperature on the performance of asphalt mixture, the experimental results are related to the external temperature during the experiment, and the obtained data has great uncertainty;

3. The circular test piece is used for testing, which cannot reflect the force condition of the pavement structure well;

4. When side load is applied, the acting area is unique and not representative.

Contents of the invention

The purpose of the present invention is to overcome the existing problems in the prior art, to provide a kind of asphalt mixture shear strength tester that simulates the actual wheel load, can apply dynamic load, simulate the actual wheel load, and complete the asphalt mixture shear strength test .

In order to achieve the above object, the present invention adopts following technical scheme:

It includes an environmental chamber equipped with a heating device. The environmental chamber is equipped with a loading wheel and a trial platform. The loading wheel is connected to the first power device for driving the loading wheel to exert pressure on the test piece and move back and forth in the horizontal direction through a connecting rod. , the loading wheel is located above the test mold cap;

A temperature sensor is installed in the environment box, a displacement sensor and a force sensor are installed on the connecting rod, and the temperature sensor, the displacement sensor and the force sensor are all connected to the control panel.

Further, the environmental box includes an inner wall and an outer wall, and the heating device includes an electric heating wire arranged between the outer wall and the inner wall of the environmental box.

Further, the inner wall of the environmental box adopts a detachable heat-proof plate, and the outer wall is made of stainless steel; a thermal insulation material is arranged between the outer wall and the inner wall of the environmental box.

Further, four wheels and four support bases are installed on the bottom of the environmental box.

Further, the loading wheel is connected to the first power unit through a connecting rod and a conduit. A horizontal first slide rail is installed on the inside of the top of the environmental box. The first slide rail is connected to the wheel suspension plate through a pulley. The connecting rod is vertically arranged and Go through the wheel hanger.

Further, there is a threaded connection between the loading wheel and the connecting rod.

Furthermore, the trial mold cap is installed in the environmental chamber through the pulley and the second horizontal slide rail, and the trial mold cap is connected to the second power device for driving the trial mold cap to slide back and forth in the horizontal direction through the dowel bar, and the environment The side wall of the box is provided with a through hole for the test mold cap to slide out; the side wall of the trial mold cap is provided with a positioning nut.

Further, a door with a glass window is provided on the side wall of the environmental box provided with the through hole.

Further, both the first power device and the second power device adopt servo hydraulic machines.

Further, the object to be tested is in the shape of a cuboid.

Compared with the prior art, the present invention has the following beneficial technical effects:

The invention can adjust the different ambient temperatures required for the experiment by adding an environment box with a heating device; at the same time, by setting the loading wheel and the test mold cap, the actual wheel load can be simulated, and the shear strength test of the asphalt mixture can be carried out; Different loading types are controlled by setting displacement sensors, force sensors and control panels. Among them, the force sensor can obtain the dynamic load confinement pressure of the test piece, and the displacement sensor can obtain the displacement change of the loaded wheel to achieve the size of the shear load. and displacement, thereby controlling different loading types, such as iso-strain or iso-stress loading. The invention can test the anti-shear strength of the asphalt mixture under the conditions of effectively simulating the actual environment temperature and the dynamic load of the road surface, which is consistent with the actual situation and has high accuracy.

Further, the inner wall of the environmental box of the present invention adopts a detachable heat-proof plate to reduce the contamination of the heating wire by the experimental residue that may fall during the experiment; the outer wall is made of stainless steel to support the box and seal the environmental box; Set up thermal insulation materials to prevent temperature leakage and increase the heating rate.

Further, the present invention provides wheels and supporting bases at the four corners of the bottom surface of the environmental chamber to facilitate the handling of the instrument, and when standing still, put away the wheels and put down the supporting base to reduce damage to the wheels and prevent unstable installation of the instrument.

Further, the present invention can apply actual dynamic wheel loads with different contact areas by using replaceable loading wheels to apply side pressure, and the dynamic load speed is controllable.

Further, the present invention provides a second slide rail so that the test mold cap can slide out, which is convenient for putting in and taking out the test piece, and can prevent the experimenter from being scalded by accidentally touching objects in the environmental chamber.

Further, the present invention is provided with a door with a glass window, which is convenient for sealing the environment box and can observe various conditions during the experiment in real time.

Further, the present invention adopts a rectangular parallelepiped to be tested, which can well reflect the force condition of the pavement structure.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the present invention.

Fig. 2(a) is a schematic diagram of the lateral pressure device of the present invention, and Fig. 2(b) is a side view of the lateral pressure device.

Fig. 3 is a schematic diagram of the control panel of the present invention.

Fig. 4(a) is a schematic diagram of a door with a glass window of the present invention, and Fig. 4(b) is a schematic diagram of a test mold cap.

Fig. 5 is a distribution diagram of the heating wire of the present invention.

Fig. 6 is a circuit control diagram of the present invention.

Among them, 1 environmental chamber, 2 loading wheels, 3 wheel hanging plates, 4 dowel bars, 5 second slide rails, 6 heating wires, 7 temperature sensors, 8 displacement sensors, 9 force sensors, 10 servo hydraulic presses, 11 test mold bearings Platform, 12 control panel, 13 positioning nut, 14 door with glass window, 15 support base, 16 wheel, 17 conduit, 18 connecting rod, 19 wire.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the present invention includes an environmental chamber 1, a replaceable loading wheel 2, a wheel suspension plate 3, a dowel bar 4, a first slide rail, a second slide rail 5, a heating wire 6 surrounding four walls, and a temperature sensor 7 , Displacement sensor 8, Force sensor 9, Servo hydraulic press 10, Die test platform 11, Control panel 12, Locating nut 13, Door with glass window 14, Four supporting bases 15, Four wheels 16, Multiple conduits 17 , Connecting rods 18, a plurality of wires 19.

The four wheels 16 are respectively located at the four corners of the bottom of the environmental chamber 1, and play the role of reducing friction when the instrument needs to be moved; the four supporting bases 15 are respectively located on the outside of the four wheels 16, which play the role of fixing the instrument and avoid The instrument slides causing damage.

The environmental chamber 1 includes an inner wall and an outer wall, and the inner wall adopts a detachable heat-resistant plate to reduce the contamination of the heating wire by the experimental residue that may fall during the experiment. The outer wall is made of stainless steel to support the box and seal the environment box 1 .

The wheel hanging plate 3 is arranged horizontally and is located at the top of the environmental box 1. The wheel hanging plate 3 is connected to the inner side wall of the environmental box 1 through the pulley and the first horizontal slide rail. The loading wheel 2 is connected to the first power unit connected, the connecting rod 18 is vertically arranged and passes through the wheel suspension plate 3, and the first power unit is located outside the environmental chamber 1 to control the pressure that the loaded wheel 2 acts on the test piece, so as to simulate the actual vehicle load acting on the road surface pressure, and the first power unit can drive the loading wheel 2 to move back and forth in the horizontal direction.

The test mold cap 11 is located below the loading wheel 2; the positioning nuts 13 are located at the two ends of the right side of the trial mold cap 11, which play a role in fixing the test piece and avoiding the displacement of the test piece under the action of the moving side pressure; The force rod 4 is located on the right side of the test die cap 11 and is connected with the second power device, and the servo hydraulic press 10 is connected. The trial die cap 11 is installed in the environmental chamber 1 through the pulley and the second horizontal slide rail 5. The environmental chamber 1 There is a through hole for the test mold cap 11 to slide out on the side wall, and the second power device and the dowel 4 can drive the trial mold cap 11 to slide out of the environmental chamber 1, which is convenient for putting in the test piece; After the test mold support 11 has completely entered the environmental chamber 1, the side wall of the trial mold support 11 is flush with the side wall of the environmental chamber 1, and a glass window is provided on the side wall of the environmental chamber 1 provided with through holes. door 14. Both the first power unit and the second power unit adopt a servo hydraulic machine 10 .

Referring to Fig. 2(a) and Fig. 2(b), the loaded wheels 2 can be replaced, and representative wheels from different regions are respectively used in order to simulate the most realistic road working conditions.

Referring to Fig. 3, there are wheel up switch, power switch, wheel speed switch, side pressure size switch, equal stress load switch and equal strain load switch on control panel 12 of the present invention, also have temperature display screen, side pressure display screen and shear force display screen, and correspondingly set temperature control switch, side pressure control switch and shear force control switch on one side of each display screen.

Referring to Fig. 4 (a), a door 14 with a glass window is provided on the side wall of the environmental chamber 1, which is convenient for changing the loading wheel 2, placing the test piece and sealing the environmental chamber during the test, and can observe various conditions in the experimental process in real time. kind of situation. The test piece is in the shape of a cuboid. Referring to Fig. 4(b), the test mold bearing platform 11 is a rectangular drawer structure, which is convenient for placing the test piece.

Referring to Fig. 5, the heating wire 6 is located between the inner wall of the environmental box and the outer wall of the environmental box, and the heating wire 6 is evenly distributed in the side wall panels and the bottom wall panel to achieve uniform heating effect. Thermal insulation materials can be arranged between the outer wall and the inner wall to prevent temperature leakage and increase the heating rate.

The temperature sensor 7 is located on the upper right side of the mold test platform 11; the displacement sensor 8 and the force sensor 9 are connected to the connecting rod 18 to control the magnitude of the shear stress; the temperature sensor 7, the displacement sensor 8 and the force sensor 9 are all located in the Among them, the control panel 12 is located outside the environmental chamber 1 and is connected to the temperature sensor 7, the displacement sensor 8 and the force sensor 9 through wires 19, so as to achieve the adjustment and setting of temperature, load and displacement, as shown in FIG. 6 .

The use process of the present invention is: switch on the power supply, open the door 14 with the glass window, select a suitable loading wheel 2 according to the requirements of the experiment, after the replacement, pull out the test mold cap 11 through the second slide rail 5, and pull out the Put the test piece into the test mold cap 11, and firmly fix the test piece through the positioning nut 13 to avoid unnecessary displacement, then slide the test mold cap 11 along the second slide rail 5, and close the door with glass window 14. Set the test parameters through the control panel 12, and select the appropriate test temperature, wheel load, wheel loading speed and shear force loading type. Finally, click the start button on the control panel 12 to conduct the experiment.

The present invention can control the experiment environment, use the environment box 1 containing the electric heating wire 6 to heat, and make the environment during the experiment reach the temperature required by the experimenters. The loading wheel 2 that can replace the tire is used to simulate the situation of the actual road surface stress, and the first power unit is used to apply a load to the loading wheel 2 to provide the shear force required for the test. Through the first power unit, the wheel suspension plate 3 and the second A sliding rail cooperates to drive the loading wheel 2 to slide back and forth horizontally, so that the purpose of applying dynamic load can be achieved. The speed of the dynamic load can also be controlled and adjusted according to the actual situation. By connecting the rod 18 and the servo hydraulic machine 10, it can be loaded in different forms. Finally, the goal of simulating the shear strength of asphalt mixture under the actual ambient temperature and road surface dynamic load can be achieved.

At the same time, a displacement sensor 8 and a force sensor 9 are attached to the connecting rod 18 to control changes during the experiment in real time. An electric heating wire 6 for heating is arranged in the double-layer plywood of the environmental chamber 1 , and the temperature is regulated according to the temperature sensor 7 . The second slide rail 5 is provided under the test mold cap 11, so that the trial mold cap 11 can slide out along the track, which is convenient for putting in and taking out the test piece. The positioning nut 13 located on the right side of the test mold support platform 11 can fix the test piece at a designated position, so as to avoid unnecessary movement of the test piece due to the side dynamic load pressure applied above the test piece.

The invention adds an environmental chamber 1, which can adjust different ambient temperatures required for the experiment, and simultaneously simulate the actual wheel load to test the shear strength of the asphalt mixture. At the same time, the connecting rod 18 that exerts shear force on the side can control different loading types: equal strain or equal stress loading through the sensor and the control panel.

Claims (10)

1. An asphalt mixture shear strength tester simulating actual wheel load, is characterized in that: comprise the environmental chamber (1) that heating device is installed, be provided with loading wheel (2) and test mold in environmental chamber (1) The bearing platform (11), the loading wheel (2) is connected to the first power device for driving the loading wheel (2) to apply pressure to the test piece to be tested and to move back and forth in the horizontal direction through the connecting rod (18), and the loading wheel (2) is located at The top of the trial mold cap (11); A temperature sensor (7) is installed in the environmental box (1), a displacement sensor (8) and a force sensor (9) are installed on the connecting rod (18), the temperature sensor (7), the displacement sensor (8) and the force sensor ( 9) Both are connected to the control panel (12). 2. a kind of asphalt mixture shear strength tester simulating actual wheel load according to claim 1, is characterized in that: environment chamber (1) contains inner wall and outer wall, and heating device comprises that is arranged on environment chamber (1) Heating wire (6) between the outer wall and the inner wall. 3. a kind of asphalt mixture shear strength tester simulating actual wheel load according to claim 2, is characterized in that: the inner wall of environmental box (1) adopts the heat-proof plate that can be disassembled, and outer wall adopts stainless steel material; A thermal insulation material is arranged between the outer wall and the inner wall of the environmental box (1). 4. a kind of asphalt mixture shear strength tester simulating actual wheel load according to claim 1, is characterized in that: four wheels (16) and four support bases ( 15). 5. A kind of asphalt mixture shear strength tester simulating actual wheel load according to claim 1, is characterized in that: loading wheel (2) is connected with first power by connecting bar (18) and conduit (17) The devices are connected to each other, and a horizontal first slide rail is installed on the inside of the top of the environmental box (1). The first slide rail is connected to the wheel hanging plate (3) through a pulley, and the connecting rod (18) is vertically arranged and passes through the wheel hanging plate ( 3). 6. The asphalt mixture shear strength tester for simulating actual wheel load according to claim 1, characterized in that: the loaded wheel (2) and the connecting rod (18) are threaded. 7. A kind of bituminous mixture shear strength tester simulating actual wheel load according to claim 1, is characterized in that: test mold cap (11) is installed on the second slide rail (5) by pulley and level In the environmental chamber (1), the test mold cap (11) is connected to the second power device for driving the trial mold cap (11) to slide back and forth in the horizontal direction through the dowel rod (4), and the side of the environmental chamber (1) The wall is provided with a through hole for the trial die cap (11) to slide out; the side wall of the trial die cap (11) is provided with a positioning nut (13). 8. A kind of asphalt mixture shear strength tester simulating actual wheel load according to claim 7, is characterized in that: environmental box (1) is provided with the door ( 14). 9. The asphalt mixture shear strength tester for simulating actual wheel load according to claim 7, characterized in that: the first power unit and the second power unit both adopt servo hydraulic presses (10). 10 . The asphalt mixture shear strength tester for simulating actual wheel loads according to claim 1 , wherein the test piece is in the shape of a cuboid. 11 .