CN103149098A - Pitch rotation shear failure experimental device - Google Patents

Abstract

The experimental device for measuring the asphalt rotational shear failure performance belongs to the field of material mechanical performance testing, including an experimental platform, a temperature control system and a computer control system; the computer control system automatically controls the data information collected in real time according to the set target parameters. The specimen is subjected to rotational shear loading, and the experimental process is controlled; the temperature control system controls the experimental temperature. The invention is suitable for measuring the low-temperature brittle fracture, medium-high temperature viscoplastic failure of ordinary asphalt, SBS modified asphalt, rubber asphalt and other polymer-modified asphalt and other asphalt binders at different shear rates, and the asphalt binder under low temperature conditions. Test the mechanical properties of the bonding interface with stone, steel, plastic and other materials.

Description

Experimental device for asphalt rotational shear failure

technical field

The invention belongs to the field of testing mechanical properties of asphalt, and in particular relates to an experimental measurement technology for asphalt rotational shear failure strain, failure stress index and bonding interface failure performance. the

Background technique

The main equipment for testing the failure performance of asphalt binder is the direct tensile tester (DDT), which measures the failure strain and failure stress of the asphalt specimen under direct tension. Asphalt is often damaged by shearing. the

The only equipment that applies shear action to test the mechanical properties of asphalt binder is the dynamic shear rheometer (DSR), which measures the complex shear modulus of asphalt binder in the linear viscoelastic range at a given temperature and loading frequency. Quantity (G ^* ) and phase angle (δ) are used to evaluate the high temperature resistance to permanent deformation and medium temperature fatigue resistance of asphalt binder. Since the failure strain of asphalt has greatly exceeded the range of linear viscoelasticity, DSR cannot directly measure the failure performance index of asphalt binder.

At present, the equipment that can be used to test the torsional performance of materials includes traditional torque testing machines (manual loading) and computer-controlled torsion testing machines, both of which are mainly used to test the torsional properties of metallic materials and non-metallic materials with large shear modulus at room temperature. torsional performance. The above-mentioned torsion test equipment is not suitable for the test of the rotational (ie torsion) shear failure performance of asphalt binder. The main reasons are: (1) The mechanical properties of asphalt binder are not only significantly affected by the loading rate, but also very sensitive to the test temperature , therefore, the testing process for the destructive performance of asphalt binder must strictly control the loading rate and test temperature; (2) The shear modulus and destructive strength of asphalt binder are much smaller than that of metal materials, and the torque of the existing material torsion testing machine The measurement range of the sensor is relatively large, which makes it difficult to guarantee the accuracy of the experiment; (3) due to the low hardness of the asphalt material, a special fixture must be used to carry out the shear loading test; (4) in order to reflect the damage performance of the bonding interface between asphalt and different materials, it is necessary to Special trial molds made of different materials and matched with the clamping system. the

In order to overcome the above-mentioned problems existing in the prior art, the present invention provides a method that can measure asphalt rotational shear failure (including low-temperature brittle fracture, medium-high temperature viscoplastic failure and low-temperature Interface damage, etc.) experimental equipment and methods of performance indicators. the

Contents of the invention

In order to measure the rotational shear failure strain and failure stress of asphalt binder under different temperature, shear rate and bonding interface conditions, the invention provides an asphalt rotational shear failure experimental device. The experimental device consists of an experimental platform, experimental specimens, loading facilities, temperature control system and computer control system. The computer control system automatically controls the loading facility according to the set target parameters and real-time collected data information, performs rotational shear loading on the experimental specimen, and controls the experimental process; the temperature control system controls the experimental temperature. the

The experimental platform is composed of basic steel plates, bearing supports, fixed shafts, rotating shafts, experimental specimens, fixtures, couplings, loading facilities, torque sensors and encoders, and angular displacement sensors and encoders; the two are used to support The bearing supports of the fixed shaft and the rotating shaft are fixed on the base steel plate; the fixed shaft and the rotating shaft are on the same line and placed on the bearing supports; the rotating shaft can move along the axial direction, which is convenient for fixing the experimental specimens on Between the rotating shaft and the fixed shaft; one end of the rotating shaft is detachably fixedly connected to the fixture, and the other end is connected to the loading facility through a coupling; one end of the fixed shaft is connected to the experimental specimen through the fixture, and the other end is connected to the torque sensor and The encoder is fixedly connected; the torque sensor and the encoder are fixed on the base steel plate; the loading facility drives the rotating shaft to rotate, so that the experimental specimen sandwiched between the rotating shaft and the fixed shaft is deformed; the angular displacement sensor and the encoder are fixed on the rotating shaft used to measure the angular displacement of the specimen. the

The loading facility is composed of a frequency converter, a micro motor, a gearbox and a coupling. The micro motor and the gearbox are used together, and the coupling is used to connect the rotating shaft and the output shaft of the gearbox. the

The experimental specimen includes a fixture, two test molds and an asphalt specimen; both the test mold and the asphalt specimen are cylindrical specimens with the same bottom area; the asphalt specimen is fixedly sandwiched between the two test molds, and the fixture The fixed test mold and the asphalt specimen are clamped in the middle; one end of the fixture is detachably fixedly connected to the fixed shaft, and the other end is detachably fixedly connected to the rotating shaft. the

The temperature control system is composed of a high and low temperature test box, a temperature control pool, an asphalt test piece curing rack, a water bath, a water bath inlet pipe, a water bath outlet pipe, a temperature sensor, a temperature encoder and a micro-water pump. Among them, the temperature control pool and the asphalt specimen curing frame are fixed in the high and low temperature test box. The water bath is located directly below the asphalt specimen and the test mold. One end of the water inlet pipe of the water bath is connected to the temperature control pool, and the other end is fixed above the test mold and the asphalt specimen through the bearing support. The two ends of the outlet pipe of the water bath are respectively connected with the water bath and the temperature control pool. The tip of the temperature sensor is placed in the water bath. The inlet pipe of the water bath and the outlet pipe of the water bath are provided with micro-pumps near the end of the experimental platform. The water inlet pipe of the water bath pumps the constant temperature water out of the temperature control pool through the micro pump, and continuously pours the constant temperature water on the surface of the test mold and the asphalt test piece, and the constant temperature water flows into the water bath; at the same time, the outlet pipe of the water bath passes through the micro pump Pump the water from the water bath back into the temperature controlled pool. The water bath, temperature encoder and micro water pump are all fixed on the experimental platform. the

The computer control system automatically controls the experimental process and loading facilities according to the information collected by the angular displacement sensor and encoder, torque sensor and encoder, temperature sensor and temperature encoder. the

The test mold is made of stone, steel, high-temperature-resistant plastic or other materials, and is used to test the failure performance of the bonding interface between asphalt binder and different materials. the

Asphalt rotational shear failure test method is as follows:

1) Experiment parameter setting: set the basic size parameters of the asphalt specimen, the target temperature of the experiment, and the end conditions of the experiment (that is, the shortest time for continuous measurement and the minimum detection torque value) through the computer control system; set the work of the frequency converter through the computer control system Frequency, to complete the setting of parameters such as the target constant speed of the micro-motor or the target variable speed function. the

2) Test piece preparation and temperature control system startup: Make the asphalt test piece into a cylinder with the same area as the bottom of the test mold, open the high and low temperature test chamber, put the asphalt test piece and test mold on the asphalt test piece curing rack for curing, Start the micro water pump to make the water circulation system including the water bath inlet pipe, the water bath outlet pipe, the water bath, and the temperature control pool start to work. Start the computer control system to receive the data collected by the temperature sensor and the temperature encoder, and start temperature monitoring. the

3) Test piece installation: The computer control system prompts that the temperature of the water bath meets the experimental requirements. At the same time, after the curing temperature and curing time of the asphalt test piece meet the specified requirements, the asphalt test piece and the test mold are taken out from the asphalt test piece curing rack and installed with fixtures. on fixed and rotating axes. the

4) Experimental stage:

Step 1: The computer control system monitors the temperature of the water bath through a temperature sensor and a temperature encoder. When the target experimental temperature is met for a certain period of time, it will automatically prompt the experiment to start. the

Step 2: According to the set experimental target parameters, the computer control system drives the rotating shaft to rotate at the set constant target speed or the target speed change function through the loading facility, so as to apply shearing action to the asphalt specimen. the

Step 3: The computer control system collects the dynamic information transmitted by the angular displacement sensor and encoder, torque sensor, encoder, temperature sensor, and temperature encoder in real time, and adjusts and controls according to the target experimental parameters until the asphalt specimen is destroyed and reaches the test value. End conditions (satisfy the minimum test time and detect the minimum torque). the

Step 4: The computer control system automatically saves the angular displacement and time, torque and time, temperature data and time data collected in real time, and automatically calculates the time-dependent changes in the damage process of the asphalt specimen according to the basic size parameters (radius, thickness) of the asphalt specimen The shear strain and shear stress can automatically determine the maximum shear stress and the corresponding shear strain, time and other parameters, calculate the secant shear modulus, fit the tangent shear modulus, and complete the drawing of the screen graphics. the

Step 5: The computer control system prompts to take out the asphalt specimen and check the damage pattern, and the experiment ends. the

The beneficial effect of the present invention is that it provides an experimental device and method capable of measuring various performance indicators of asphalt rotational shear failure under different temperatures, different shear rates and different material bonding interfaces. The invention is suitable for measuring the low-temperature brittle fracture, medium-high temperature viscoplastic failure of ordinary asphalt, SBS modified asphalt, rubber asphalt and other polymer-modified asphalt and other asphalt binders at different shear rates, and the asphalt binder under low temperature conditions. Various destructive performance indicators of the bonding interface with stone, steel, plastic and other materials. the

Description of drawings

Accompanying drawing is the structural representation of the present invention. the

In the figure: 1. Computer control system, 2. Torque sensor and encoder, 3. Fixed shaft, 4. Temperature sensor, 5. Asphalt specimen, 6. Angular displacement sensor and encoder, 7. Rotary shaft, 8. Experiment Platform, 9. frequency converter, 10. loading facility, 11 bearing support, 12. water bath inlet pipe, 13. water bath outlet pipe, 14. clamp, 15. water bath, 16. reduction box, 17. micro motor, 18. Temperature control pool, 19. Asphalt specimen curing frame, 20. High and low temperature test box, 21. Micro water pump, 22. Trial mold, 23. Coupling, 24. Temperature encoder. the

Detailed ways

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

The asphalt rotational shear failure experimental device consists of an experimental platform 8 , an experimental specimen, a loading facility 10 , a temperature control system and a computer control system 1 . The computer control system 1 automatically controls the loading facility 10 according to the set target parameters and real-time collected data information, performs rotational shear loading on the experimental specimen, and controls the experimental process; the temperature control system controls the experimental temperature. the

The experimental platform 8 consists of a base steel plate, a bearing support 11, a fixed shaft 3, a rotating shaft 7, an experimental specimen, a fixture 14, a shaft coupling 23, a loading facility 10, a torque sensor and an encoder 2, and an angular displacement sensor and an encoder 6 Composition; two bearing supports 11 respectively used to support the fixed shaft 3 and the rotating shaft 7 are fixed on the base steel plate; the fixed shaft 3 and the rotating shaft 7 are located on the same line and placed on the bearing supports 11; the rotating shaft 7 can move along the axial direction, which is convenient for fixing the experimental specimen with the fixture 14 between the rotating shaft 7 and the fixed shaft 3; one end of the rotating shaft 7 is detachably connected to the fixture, and the other end is connected to the loading device through a coupling 23. The facility 10 is connected; one end of the fixed shaft 3 is connected with the experimental specimen through the clamp 14, and the other end is fixedly connected with the torque sensor and the encoder (2); the torque sensor and the encoder 2 are fixed on the base steel plate; the loading facility 10 drives the rotating shaft 7 rotates to deform the experimental specimen sandwiched between the rotating shaft 7 and the fixed shaft 3; the angular displacement sensor and encoder 6 are fixed on the rotating shaft 7 for measuring the angular displacement of the specimen. the

The loading facility consists of a frequency converter 9, a micro motor 17, a reduction box 16 and a shaft coupling 23. The micro motor 17 is used in combination with the reduction box 16, and the coupling 23 is used to connect the rotating shaft 7 and the output shaft of the reduction box 17 . the

Experimental specimen comprises fixture 14, two test molds 22 and asphalt specimen 5; Test mold 22 and asphalt specimen 5 are all cylindrical specimens with equal bottom area; With two test molds 22, asphalt specimen 5 is fixedly Clamped in the middle, the fixture 14 clamps the fixed test mold 22 and the asphalt test piece 5 in the middle; one end of the fixture 14 is detachably fixedly connected to the fixed shaft 3, and the other end is detachably fixedly connected to the rotating shaft 7. the

The temperature control system consists of a high and low temperature test box 20, a temperature control pool 18, an asphalt specimen maintenance rack 19, a water bath 15, a water bath inlet pipe 12, a water bath outlet pipe 13, a temperature sensor 4, a temperature encoder 24 and a micro water pump 21 composition. Wherein the temperature control pool 18 and the asphalt specimen maintenance rack 19 are fixed in the high and low temperature test box 20 . The water bath 15 is placed on the asphalt specimen 5 and the test mold 22 just below the test platform. One end of the water bath inlet pipe 12 is connected with the temperature control pool 18, and the other end is fixed on the test mold 22 and the asphalt test piece 5 directly above by the bearing support 11. Both ends of the water bath outlet pipe 13 are connected with the water bath 15 and the temperature control pool 18 respectively. The end of the temperature sensor 4 is placed in the water bath 15 . The water bath inlet pipe 12 and the water bath outlet pipe 13 are provided with a micro water pump 21 near the end of the experimental platform 8 . The water bath inlet pipe 12 pumps the constant temperature water out of the temperature control pool 18 through the micro water pump 21, and pours the constant temperature water on the surface of the test mold 22 and the asphalt test piece 5 without interruption, and the constant temperature water flows into the water bath 15; at the same time, the water The bath water outlet pipe 13 returns the water pump in the water bath 15 to the temperature control pool 18 through the miniature water pump 21 . The water bath 15, the temperature encoder 24 and the miniature water pump 21 are all fixed on the experimental platform 8. the

The computer control system 1 automatically controls the experimental process and the loading facility 10 according to the information collected by the angular displacement sensor and the encoder 6, the torque sensor and the encoder 2, the temperature sensor 4 and the temperature encoder 24. the

The test mold 22 is made of stone, steel, high-temperature-resistant plastic or other materials, and is used to test the failure performance of the bonding interface between the asphalt binder and different materials. the

The experimental method is as follows:

Experimental parameter settings:

Set the asphalt test piece 5 basic size parameters, the target temperature of the experiment, the end condition of the experiment (i.e. the shortest time of continuous measurement and the minimum detection torque value) by the computer control system 1; set the operating frequency of the frequency converter 9 by the computer control system 1, Complete the setting of parameters such as the target constant speed of the micro-motor 17 or the target variable speed function. the

Specimen preparation and temperature control system startup:

The asphalt test piece 5 is made into a cylinder with the same bottom area as the test mold 22, the high and low temperature test chamber 20 is opened, the asphalt test piece 5 and the test mold 22 are placed in the asphalt test piece maintenance frame 19 for maintenance, and the micro water pump 21 is started to The water circulation system comprising the water bath inlet pipe 12, the water bath outlet pipe 13, the water bath 15, and the temperature control pool 18 starts to work. Start the computer control system 1 to receive the data collected by the temperature sensor 4 and the temperature encoder 24, and start temperature monitoring. the

Test piece installation:

The computer control system 1 prompts that the temperature of the water bath 15 meets the experimental requirements. At the same time, after the curing temperature and curing time of the asphalt test piece 5 meet the specified requirements, the asphalt test piece 5 and the test mold 22 are taken out from the asphalt test piece maintenance frame 19, and the asphalt test piece 5 and the test mold 22 are taken out from the asphalt test piece maintenance frame 19, and the asphalt test piece 5 is taken out from the asphalt test piece maintenance frame 19, and the asphalt test piece 5 is used. Installed on the fixed shaft 3 and the rotating shaft 7. the

Experimental stage:

Step 1: The computer control system 1 monitors the temperature of the water bath 15 through the temperature sensor 4 and the temperature encoder 24, and will automatically prompt the experiment to start when the target experiment temperature is met for a certain period of time. the

Step 2: The computer control system 1 drives the rotating shaft 7 through the loading facility 10 to rotate at a set constant target speed or a target variable speed function according to the set experimental target parameters, thereby exerting a shearing action on the asphalt specimen 5 . the

Step 3: The computer control system 1 collects the dynamic information transmitted by the angular displacement sensor and the encoder 6, the torque sensor and the encoder 2, the temperature sensor 4, and the temperature encoder 24 in real time, and adjusts and controls according to the target experimental parameters until the asphalt test Part 5 is destroyed and the end condition of the experiment is reached (satisfying the shortest test time and detecting the minimum torque). the

Step 4: The computer control system 1 automatically saves the angular displacement and time, moment and time, temperature data and time data collected in real time, and automatically calculates the asphalt test piece according to the basic size parameters (radius, thickness) of the asphalt test piece 5. Time-varying shear strain and shear stress, automatically determine the maximum shear stress and the corresponding shear strain, time and other parameters, calculate the secant shear modulus, fit the tangent shear modulus, and complete the screen graphics drawing. the

Step 5: The computer control system 1 prompts to take out the asphalt specimen 5 and check the damage form, and the experiment ends. the

Claims (6)

1. pitch rotational shear breaking test device, formed by experiment porch (8), experiment test specimen, loading facility (10), temperature control system and computer control system (1), it is characterized in that computer control system (1) is according to the target component of setting and the automatic controlled loading facility of experimental data information (10) of Real-time Collection, the experiment test specimen is rotated shears loading, and control experimentation; Temperature control system is controlled experimental temperature.

2. pitch rotational shear breaking test device according to claim 1, it is characterized in that experiment porch (8) by base steel plates, bearing spider (11), stationary shaft (3), turning axle (7), experiment test specimen, fixture (14), shaft coupling (23), load facility (10), shaft coupling (23), torque sensor and scrambler (2) and angular displacement sensor and scrambler (6) and form; Two are fixed on base steel plates in order to the bearing spider (11) that supports stationary shaft (3) and turning axle (7) respectively; Stationary shaft (3) is positioned on the same level straight line with turning axle (7), and stationary shaft (3) is placed in respectively on its bearing spider (11) separately with turning axle (7); Turning axle (7) can be movable along axis direction, is convenient to the experiment test specimen is fixed between turning axle (7) and stationary shaft (3) with fixture (14); One end of turning axle (7) is dismountable being fixedly connected with fixture, and the other end is connected with loading facility (10) by shaft coupling (23); One end of stationary shaft (3) is connected with the experiment test specimen by fixture (14), and the other end is fixedly connected with torque sensor and scrambler (2); Torque sensor and scrambler (2) are fixed on base steel plates; Load facility (10) by shaft coupling (23) driven rotary axle (7) rotation, make the experiment test specimen that is clipped between turning axle (7) and stationary shaft (3) produce distortion; It is upper for measuring the test specimen angular displacement that angular displacement sensor and scrambler (6) are fixed on turning axle (7); Loading facility is comprised of frequency converter (9), micromachine (17) and reducer casing (16), frequency converter is arranged on department of computer science and unifies between micromachine, and the order tape actuating miniature motor rotation that sends according to computing machine, micromachine (17) is used in combination with reducer casing (16), and shaft coupling (23) is used for connecting the output shaft of turning axle (7) and reducer casing (17).

3. pitch rotational shear breaking test device according to claim 2, is characterized in that testing test specimen and comprise fixture (14), two die trials (22) and pitch test specimen (5); Die trial (22) is all with pitch test specimen (5) cylinder specimen that floorage equates; With two die trials (22), pitch test specimen (5) is clipped in the middle regularly, fixture (14) is clipped in the middle die trial (22) and the pitch test specimen (5) that fixes again; One end of fixture (14) and stationary shaft (3) be for detachably being fixedly connected with, the other end with turning axle (7) for detachably being fixedly connected with.

4. pitch rotational shear breaking test device according to claim 1, is characterized in that temperature control system is comprised of high low temperature experimental box (20), temperature-controlled pool (18), pitch test piece maintenance frame (19), sea water bath (15), sea water bath water inlet pipe (12), sea water bath rising pipe (13), temperature sensor (4), temperature scrambler (24) and micro pump (21); Wherein temperature-controlled pool (18) and pitch test piece maintenance frame (19) are fixed in high low temperature experimental box (20); Sea water bath (15) is placed under pitch test specimen (5) and die trial (22) on experiment porch; One end of sea water bath water inlet pipe (12) is connected with temperature-controlled pool (18), and the other end is fixed in directly over die trial (22) and pitch test specimen (5) by bearing spider (11); The two ends of sea water bath rising pipe (13) are connected 18 with sea water bath (15) with temperature-controlled pool respectively) be connected; The termination of temperature sensor (4) is placed in sea water bath (15); Sea water bath water inlet pipe (12), sea water bath rising pipe (13) arrange micro pump (21) at the end near experiment porch (8); Sea water bath water inlet pipe (12) pumps thermostatted water by micro pump (21) from temperature-controlled pool (18), and thermostatted water uninterruptedly is cast in die trial (22) and pitch test specimen (5) surface, and thermostatted water imports sea water bath (15); Simultaneously, sea water bath rising pipe (13) returns the water pump in sea water bath (15) to temperature-controlled pool (18) by micro pump (21); Sea water bath (15), temperature scrambler (24) and micro pump (21) all are fixed on the base steel plates of experiment porch (8).

5. according to claim 3 or 4 described pitch rotational shear breaking test devices is characterized in that die trial (22) made by stone material, steel, high-temperature resistance plastice or other material, in order to test the bonding interface destructive characteristics of bituminous cements and different materials.

6. pitch rotational shear breaking test method:

1) experiment parameter setting: target temperature, the experiment termination condition (being shortest time and the minimum detection torque value of test constantly) of setting pitch test specimen (5) parameters of basic dimensions, experiment by computer control system (1); The frequency of operation of frequency converter (9) is set by computer control system (1), completes target constant rotational speed or the isoparametric setting of target shift speed function to micromachine (17);

2) test specimen is prepared and the temperature-controlling system startup: pitch test specimen (5) is made into the right cylinder identical with die trial (22) floorage, open high low temperature experimental box (20), pitch test specimen (5) and die trial (22) are placed in pitch test piece maintenance frame (19) carry out maintenance, start micro pump (21) water circulation system that comprises sea water bath water inlet pipe (12), sea water bath rising pipe (13), sea water bath (15), temperature-controlled pool (18) is started working; Start the data that computer control system (1) receives temperature sensor (4), temperature scrambler (24) collection, the beginning temperature monitoring;

3) test specimen is installed: computer control system (1) prompting sea water bath (15) temperature satisfies requirement of experiment, after pitch test specimen (5) curing temperature and curing time satisfy the regulation requirement simultaneously, pitch test specimen (5) and die trial (22) are taken out from pitch test piece maintenance frame (19), be arranged on stationary shaft (3) and turning axle (7) with fixture (14);

4) experimental phase: step 1: computer control system (1) begins the automatic-prompting experiment after satisfying target experimental temperature certain hour by the temperature of temperature sensor (4), temperature scrambler (24) monitoring sea water bath (15);

Step 2: computer control system (1) drives turning axle (7) by the constant target rotating speed rotation of setting or the rotation of target shift speed function according to the object of experiment parameter of setting by loading facility (10), thereby pitch test specimen (5) is applied shear action;

Step 3: the multidate information that computer control system (1) Real-time Collection angle displacement transducer and scrambler (6), torque sensor and scrambler (2) and temperature sensor (4), temperature scrambler (24) transmit, adjust and control according to the target experiment parameter, until till pitch test specimen (5) destroys, reaches experiment termination condition (satisfy the shortest experimental period and detect minimal torque);

Step 4: computer control system (1) is preserved angular displacement and the data such as time, moment and time, temperature data and time of Real-time Collection automatically, automatically calculate time dependent shearing strain and shear stress in pitch test specimen destructive process according to pitch test specimen (5) parameters of basic dimensions (radius, thickness), the parameters such as the shearing strain of automatically definite maximum shear and correspondence, time, calculate secant shear modulus, match cropping shears shear modulu, and complete screen graph and draw;

Step 5: pitch test specimen (5) is taken out in computer control system (1) prompting and examination destroys form, and experiment finishes.

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