WO2021135162A1

WO2021135162A1 - Ground-push-type shear strength test device and measurement method therefor

Info

Publication number: WO2021135162A1
Application number: PCT/CN2020/102443
Authority: WO
Inventors: 金光来; 周文; 翟金陵; 周明伟; 杨福猛
Original assignee: 江苏中路工程技术研究院有限公司; 江苏中路交通科学技术有限公司
Priority date: 2019-12-31
Filing date: 2020-07-16
Publication date: 2021-07-08
Also published as: CN110987664B; CN110987664A

Abstract

Disclosed is a ground-push-type shear strength test device, comprising an acquisition control system, a main machine, a clamp and a heating and heat preservation system, wherein the heating and heat preservation system is used for providing a required ambient temperature for the main machine, the clamp and a test piece fixed on the clamp. The test piece is provided with two parts connected by means of a plane, wherein the clamp fixes a first part of the two parts, and under the control by the acquisition control system, the main machine applies, to the other part of the test piece, a force parallel to a plane direction. The test device can be used for shear strength testing of a test piece in different situations, has a wide test piece application range, and breaks the limitation of a traditional shearing apparatus wherein same has a single practical range. The test device can also measure shear strengths in different temperature ranges, can simulate an actual environment of a road surface, and facilitates the reflection of the actual shear strength of a bonding material. Further disclosed is a ground-push-type shear strength measurement method, wherein same has the same technical effect.

Description

Ground-push type shear strength test device and test method thereof

Technical field

The invention relates to the technical field of pavement structure performance testing, in particular to a ground-pushing shear strength test device and a test method thereof.

Background technique

Asphalt pavement is the main form of road surface in my country. Due to the continuous increase in traffic volume and axle load, as well as various reasons such as asphalt pavement structure design and construction management, many new and reconstructed asphalt pavements in my country have produced different types of diseases. The performance of the shear failure between the new pavement layers is particularly prominent, and the shear failure of the splicing part of the new and old pavement of the expanded road is particularly prominent. Therefore, it is particularly important to evaluate the shear resistance of the materials between the asphalt pavements of newly-built roads and the splicing parts of new and old roads on extended roads.

There are many kinds of testing equipment for the shear strength evaluation of the interlayer material of the newly built road, such as oblique shear, direct shear and torsion shear, but the equipment is prone to bending deformation of the fixture during the actual experiment process; and most of the shearing equipment is not With its own control system and force transmission loading system, most of them are just customized shearing fixtures, and then the fixtures are placed in the MTS similar to the testing machine (asphalt mixture dynamic stability loading equipment, etc.), there is no special loading for shearing equipment For systems and sensors, during the test, the MTS loading force value and the actual force value of the test piece are not calibrated, the test results are not accurate, and the customized test piece fixture may not match the table of the MTS loading system, and the fixture is fixed The problem of insufficient stability will also affect the test results. Generally, after several tests, the MTS indenter is bent or the specimen fixture is bent and deformed due to the unstable installation fixture, and the service life of the equipment is not long enough.

For the evaluation of the shear strength of the splicing materials of the new and old pavement of the expanded road, there is currently no shearing equipment for splicing new and old pavement specimens at home and abroad, and the shear strength test method of the cylindrical splicing specimens is also missing.

In view of the above-mentioned shortcomings in the existing test equipment and evaluation methods for evaluating the shear performance of materials between the asphalt surface layers of new roads and the splicing parts of new and old roads on expanded roads, the inventors have been engaged in the design and manufacture of such products for many years. Practical experience and professional knowledge, coupled with the application of academic theory, actively research and innovate, in order to create a ground-push-type shear strength test device and its test method to make it more practical. After continuous research, design, and repeated trials and improvements, finally created the present invention with real practical value.

Summary of the invention

The main purpose of the present invention is to overcome the shortcomings of the existing shear strength test, and to provide a ground-based push-type shear strength test device, which improves the detection accuracy and is more suitable for practical use. At the same time, the present invention also claims protection A test method based on ground-push shear strength has the same technical effect and has industrial use value.

In order to achieve the above objective, the technical solution adopted by the present invention is: a ground-push type shear strength test device, including a control acquisition system, a host, a fixture and a heating and heat preservation system;

The heating and heat preservation system is used to provide the required ambient temperature for the host, the clamp and the test piece fixed on the clamp;

The test piece has two parts connected by a plane, the clamp fixes the first part thereof, and the host applies a direction parallel to the plane on the other part of the test piece under the control of the control acquisition system的力。 The force.

Further, the host includes a transmission loading system, a tensile force sensor, a base, a beam and an indenter;

The transmission loading system is fixed on the machine base, the tension sensor is connected to the power output end of the transmission loading system and the cross beam, the indenter is fixed to the end of the cross beam, and the cross beam is at the end of the cross beam. Driven by the transmission loading system, it moves along a straight line, thereby applying force to a part of the test piece through the indenter.

Further, there is a column between the beam and the indenter, and the indenter is movably arranged up and down along the column.

Further, the cross beam includes a hinge seat, a force receiving body and a sliding guide device;

The hinge seat is hinged with one end of the tension sensor through a rotating shaft, the force receiving body fixes the hinge seat, and the bottom of the hinge seat is connected with the sliding guide device to realize linear movement.

Further, the column includes a guide rod, a screw rod and a screw nut;

The guide rod is provided with a guide groove for partially covering the indenter, the screw nut is threadedly connected with the screw rod and is used to fix the indenter, and the screw rod is connected to the screw rod. The length directions of the guide grooves are arranged in parallel, and during the rotation of the screw rod, the screw nut drives the indenter to move linearly along the guide groove.

Further, the clamp includes two clamping plates for clamping both ends of the test piece, and the clamping plates are movably arranged and move along a straight line;

It also includes at least two supporting plates for supporting the periphery of the test piece and arranged at intervals, wherein at least one of the supporting plates is movably arranged and moves along the same straight line as the clamping plate.

Further, the supporting part of the support plate for supporting the test piece includes at least one cushion structure that is adapted to the surface of the test piece, and the increase or decrease of the cushion structure is used to adapt to a variety of For the size of the test piece, each of the cushion structure and the main body of the support plate are connected by a pressure block.

Further, the clamp includes two clamping blocks arranged symmetrically for covering the periphery of the test piece and in contact with the test piece, and the two clamping blocks are movably arranged and move along a straight line;

The end of the indenter is adapted to fit the outer shape of the test piece, and the side surface is fit to the side surface of one of the clamping blocks.

Further, the heating and heat preservation system includes a power supply, a heating element, a temperature sensor and a heat preservation box;

The power supply realizes the on and off of the power supply and the control signal under the control of the control acquisition system, the heating element is used to realize the heating in the incubator, the temperature sensor senses the temperature and feeds it back to the The control acquisition system.

A ground-push type shear strength test method, including the following steps:

S1: Preparation or processing of test pieces;

S2: Install the test piece and keep it warm;

S3: Load until the specimen is destroyed;

S4: Calculate the shear strength=F/S, where S is the failure area.

Through the above technical solutions, the beneficial effects of the present invention are:

1. The shear test of the present invention has different fixture forms, which can be used for the shear strength of test pieces in different situations, including the bonding material between the new and old road asphalt layers and the splicing material of the new and old pavement of the expanded road. It can be applied to the asphalt surface layer or The water-stabilized base has a wide application range, breaking the limitation of the single practical range of traditional shearing equipment;

2. The shearing equipment contains an independent dedicated control acquisition system, which can be set with touch screen, printer and microcomputer, etc. The device can independently complete the shearing test, and the sensor is accurate, the loading force value and the acquisition force value are calibrated, and the test result is accurate. The main agent has a high matching degree with the fixture, and the fixture is easy to fix, avoiding bending and deformation of the fixture or the force transmission rod;

3. The control acquisition system, host, fixture, and heating and heat preservation system can all be disassembled and assembled for easy handling. The power supply can adopt vehicle-mounted wiring, which is suitable for on-site testing;

4. The present invention can test the shear strength in different temperature ranges, can simulate the actual environment of the road surface, and is beneficial to the actual shear strength of the reactive bonding material.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Fig. 1 is a schematic diagram of the structure of the ground-pushing shear strength test device at a first angle;

Figure 2 is a schematic diagram of the structure of the ground-pushing shear strength test device at a second angle (rotated 90° clockwise);

Figure 3 is a partial enlarged view of A in Figure 1;

Figure 4 is a partial enlarged view at B in Figure 2;

Figure 5 is a schematic diagram of the structure of the column;

Figure 6 is a schematic diagram of a structure of the fixture, on which a test piece is installed;

FIG. 7 is a schematic diagram of the structure of the clamp in FIG. 6 after the test piece is removed;

Figure 8 is a front view of Figure 7;

Fig. 9 is a partial enlarged view of C in Fig. 7;

Figure 10 is a schematic diagram of the installation of the cushion structure;

Figure 11 is a schematic diagram of another structure of the clamp;

Figure 12 is a schematic structural diagram of an indenter adapted to the clamp in Figure 11;

Reference signs: transmission loading system 1, tension sensor 2, machine base 3, cross beam 4, hinge seat 41, force receiving body 42, sliding guide device 43, pressure head 5, column 6, guide rod 61, guide groove 61a, wire Rod 62, screw nut 63, clamping plate 7, supporting plate 8, cushion structure 81, pressing block 9, clamping block 10.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and comprehensively described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

As shown in Figures 1 and 2, a ground-pushing shear strength test device includes a control acquisition system, a host, a fixture and a heating and heat preservation system; the heating and heat preservation system is used to provide the host, fixtures and test pieces fixed on the fixtures The required ambient temperature; the test piece has two parts connected by a plane, the first part of which is fixed by the clamp, and the host exerts a force parallel to the plane direction on the other part of the test piece under the control of the control acquisition system. The invention can be used for the shear strength test of test pieces in different situations. The test pieces can represent the bonding material between the new and old road asphalt layers and the splicing material of the new and old pavement of the expanded road. It can be applied to the asphalt surface layer or the water-stable base layer and has a wide application range. It breaks the limitation of the single practical range of the traditional shearing equipment. The present invention can test the shear strength in different temperature ranges, can simulate the actual environment of the road surface, and is beneficial to the actual shear strength of the reactive bonding material.

The control acquisition system can be composed of touch screen, printer and microcomputer. It has stable loading and accurate measurement. It can set a variety of curve forms to choose, so as to quickly and accurately realize the digital calibration of load and elongation. It can set full load protection and position protection. The test data can be accessed at will and the re-analysis of data and curves can be realized, including partial amplification and data re-editing, the test method is programmable, and can be stored or read, and the mechanical properties of the material can be automatically calculated.

And print out the complete test report and curve.

As a preference of the above embodiment, the host includes a transmission loading system 1, a tension sensor 2, a frame 3, a beam 4, and a pressure head 5; the transmission loading system 1 is fixed on the frame 3, and the tension sensor 2 is connected to the power of the transmission loading system 1. The output end and the beam 4, and the indenter 5 is fixed at the end of the beam 4, and the beam 4 moves in a straight line under the drive of the transmission loading system 1, so that the indenter 5 applies force to a part of the test piece. In the above host structure, the tensile force sensor 2 is used as the signal collection terminal, which can quantify the force exerted by the indenter on the test piece, so that the operator can confirm the current value of the shear force on the test piece, and the linear movement of the beam 4 The certainty of the direction of the force is guaranteed, and the deviation of the test results caused by the uncertainty of the force is avoided. In this preferred scheme, the transmission loading system adopts a servo-driven reducer to move left or right to apply load to the sample to complete the sample shear strength test. It has the characteristics of accurate transmission, excellent control, and low noise. The main transmission principle is: the high-precision and wide-speed ratio range of the servo driver receives the electrical control signal, controls the high-precision and wide-speed servo motor, drives the reducer to run, and then drives the synchronous rotation through the reducer to drive the moving beam 4 to move through The indenter 5 loads the test piece.

In order to adjust the height of the indenter 5, a column 6 is also arranged between the beam 4 and the indenter 5, and the indenter 5 is movably arranged up and down along the column 6. Through the arrangement of the column 6, the height position of the indenter 5 can be adjusted, which can be applied to a wider range of test piece sizes and rapid adjustment of the edge force position.

As shown in Figures 3 and 4, the cross beam 4 includes a hinge seat 41, a force receiving body 42 and a sliding guide 43; the hinge seat 41 is hinged to one end of the tension sensor 2 through a rotating shaft, and the force receiving body 42 fixes the hinge seat 41. The bottom is connected with the sliding guide 43 to realize linear movement. The articulated connection allows the output force direction of the transmission loading system 1 to obtain a certain deviation range, avoiding jamming during the transmission process and causing damage to the transmission loading system 1 and the tension sensor 2, etc., which is effectively ensured by the sliding guide device 43 The straightness of the trajectory of the pressure 5 driven by the beam 4 is improved, and the stability of the shearing force on the specimen is ensured. Among them, because in the entire test process, the force bearing body 42 bears a large force and there is a process of multiple reciprocating cycles, so its structural strength is relatively large. In order to obtain a more stable structure, it can be strengthened Ribs and other forms to make it have a longer service life.

As shown in Figure 5, the column 6 includes a guide rod 61, a screw 62 and a screw nut 63; the guide rod 61 has a guide groove 61a that partially covers the indenter 5, and the screw nut 63 is threadedly connected to the screw 62 , And used to fix the indenter 5, the screw rod 62 is arranged in parallel with the length direction of the guide groove 61a. During the rotation of the screw rod 62, the screw nut 63 drives the indenter 5 to move linearly along the guide groove 61a. Among them, the screw rod 62 can be fixed by a connecting plate with the guide rod 61, and the connecting plate can be installed on the motor that drives the screw rod 62 to rotate. In the above structure, the upper and lower positions of the indenter 5 can be adjusted more conveniently. It is easy to realize whether the screw 62 is rotated manually or by a motor. A ruler can be set on the guide rod 61, so that the position adjustment can be visualized and the value can be read easily.

As a preference of the above embodiments, two clamp forms are provided:

Form 1:

The clamp includes two clamping plates 7 used to clamp the two end faces of the test piece. The clamping plates 7 are movably arranged and move along a straight line. The clamping force between the two clamping plates 7 can be passed through the two screw rods, and The extrusion of the two nuts screwed with the screw is realized; it also includes at least two supporting plates 8 for supporting the periphery of the test piece and arranged at intervals, wherein at least one supporting plate 8 is movably arranged and along the same straight line as the clamping plate 7 movement. As shown in Figures 6-8, a cylindrical test piece is taken as an example. In this embodiment, the aim is to realize the limit of the test piece in the length direction through the clamping plate 7, and the balance indenter 5 is opposite to the test piece. With the applied pressure, the two support plates 8 realize the effective support of the test piece, ensuring its stability during the stress process, and at least one of them is movably set so that the support position can be adjusted according to the size of the test piece, increasing Versatility. During the test, the lower part of the test piece shown in Figure 6 is fixed by the clamp, and the indenter 5 applies force to the upper part of the test piece, where the shear surface of the test piece penetrates the axis of the cylinder Horizontal plane.

Under this clamp structure, as shown in Figures 9 and 10, it is preferable that the supporting part of the supporting plate 8 used to support the test piece includes at least one layer of cushion structure 81 adapted to the surface of the test piece. The increase or decrease is used to adapt to test pieces of various sizes. Each cushion structure 81 and the main body of the support plate 8 are connected by a pressure block 9, wherein the two connecting pieces passing through the two ends of the pressure block 9 are respectively screwed into the cushion structure 81 and the support plate 8. In the main body, the connection between the two can be realized more conveniently. In order to facilitate the adjustment of the position of the pressure block 9, at least one end of the pressure block 9 for penetrating the connector can be an open groove structure connected to the edge of the pressure block 9.

Form 2: As shown in Figure 11, the fixture includes two clamping blocks 10 symmetrically arranged to cover the periphery of the test piece and the part in contact with the test piece. The two clamping blocks 10 are movably arranged and move along a straight line. The movement can be ensured by the guiding structure between the bottom of one of the clamping blocks 10 and the base 3; as shown in Figure 12, the end of the indenter 5 and the outer shape of the test piece are adapted to fit the shape. In this embodiment, a cylindrical shape Take the test piece as an example, and the side surface of the indenter 5 is attached to the side surface of one of the clamping blocks 10. In this form, the shear surface of the test piece is a plane parallel to its radial direction. The position of the two clamping blocks 10 can be moved to adapt to the force application position of the indenter 5. After adjustment, the positioning device can achieve its positioning. When force is applied , The overlapping surface of the indenter 5 and the clamping block 10 on the side surface is the shear surface.

As a preference of the above embodiment, the heating and heat preservation system includes a power supply, a heating element, a temperature sensor and an incubator; the power supply realizes the on and off of the power supply and control signals under the control of the control acquisition system, and the heating element is used to achieve temperature rise in the incubator, The temperature sensor senses the temperature and feeds it back to the control acquisition system. The instrument panel can also be set to read the values. The heating temperature range of 0-100°C can be realized through the above-mentioned device, and the incubator is transparent on one side, which is convenient for observing the test process.

A ground-push type shear strength test method, including the following steps:

S1: Preparation or processing of test pieces;

S2: Install the test piece and keep it warm;

S3: Load until the specimen is destroyed;

S4: Calculate the shear strength=F/S, where S is the failure area.

In the specific implementation process, the specific implementation steps of the above-mentioned test method are as follows:

S1: Prepare or process test pieces, which are spliced cylindrical test pieces with a diameter of 10cm or 15cm and a height of 6-20cm.

For the horizontal groove clamp shown in Figure 6-8:

The sample preparation process is as follows: forming a cylindrical asphalt mixture sample or cement stabilized gravel mixture sample with a diameter of 10cm or 15cm and a height of 6-20cm, and cut the sample into two semi-cylinders vertically along the diameter Apply the bonding material along the cut surface, and then put the other half of the test piece on top. After the bonding material is cured to form strength, a cylindrical spliced test piece with a seam in the middle is formed.

The test piece processing process is as follows: take the core of the splicing part of the new and old base layer of the site reconstruction and expansion project, and take the core along the splicing part of the new and old base layer or the surface layer, with a diameter of 10cm or 15cm, ensuring that half is the old road base or surface Layer, half of which is the new road base layer or surface layer, with the seam in the middle, cut both sides of the core sample taken out flat, and the height is 6-20cm.

For the card circle clamp as shown in Figures 11 and 12:

The preparation process of the test piece is as follows: forming a 30cm*30cm square rut board test piece with a height of 3-10cm, the material is asphalt mixture or cement stabilized gravel mixture, and after a period of cold zone or curing, apply the surface of the test piece Brush the adhesive layer material. After the adhesive layer material is demulsified, continue to form a 30cm*30cm square rut plate specimen with a height of 3-10cm on the surface of the test piece. The material is asphalt mixture. The material is rolled and cooled and demolded, and then drilled. The core sample has a diameter of 10cm and is drilled through the test piece with a height of 6-20cm.

The processing process of the test piece is as follows: take the core on the road surface and take the core on the pavement. The diameter is 10cm, and the height of the core is 6-20cm. It is enough to ensure that it contains different structural layers.

S2: Install the test piece and keep it warm, install the test pieces of different methods in the corresponding test piece fixture, open the incubator, set the required temperature (0-100°C), and keep it warm for 4-6 hours.

S3: Loading test: Turn on the loading system, adjust the height of the indenter 5 so that the height of the indenter 5 is consistent with the loading requirements, and then adjust the loading rate (0-50mm/min), when the indenter 5 is in contact with the test piece, record the displacement and The maximum force value F is recorded until the specimen undergoes shear failure.

S4: Test result processing: Calculate the shear strength=F/S, where S is the failure area.

The invention has simple operation and accurate results, can truly reflect the bonding effect of new and old pavement splicing parts of the expansion project or whether the bonding effect between pavement layers is good or bad, and has good application prospects.

Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have Various changes and improvements, these changes and improvements all fall within the scope of the claimed invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

A ground-push type shear strength test device, which is characterized in that it includes a control acquisition system, a host, a fixture, and a heating and heat preservation system; the heating and heat preservation system is used for testing the host, the fixture, and the fixture fixed on the fixture. The test piece provides the required environmental temperature; the test piece has two parts connected by a plane, the clamp fixes the first part of the test piece, and the host performs the other part of the test piece under the control of the control acquisition system. One part exerts a force parallel to the plane direction.
The ground push shear strength test device according to claim 1, wherein the host includes a transmission loading system (1), a tension sensor (2), a base (3), a beam (4) and an indenter (5); The transmission loading system (1) is fixed on the base (3), and the tension sensor (2) is connected to the power output end of the transmission loading system (1) and the beam (4) , The indenter (5) is fixed to the end of the beam (4), and the beam (4) moves along a straight line under the drive of the transmission loading system (1) to pass the indenter (5) Apply force to a part of the test piece.
The ground-pushing shear strength test device according to claim 2, wherein a column (6) is further provided between the beam (4) and the indenter (5), and the indenter (5) ) It is movably arranged up and down along the upright column (6).
The ground-pushing shear strength test device according to claim 2 or 3, wherein the beam (4) includes a hinge seat (41), a force receiving body (42) and a sliding guide device (43); The hinge seat (41) is hinged with one end of the tension sensor (2) through a rotating shaft, the force receiving body (42) fixes the hinge seat (41), and its bottom is connected to the sliding guide device (43) Connect to achieve linear motion.
The ground-pushing shear strength test device according to claim 3, wherein the column (6) comprises a guide rod (61), a screw rod (62) and a screw nut (63); the guide rod (61) is provided with a guide groove (61a) for partially covering the indenter (5), the screw nut (63) is threadedly connected with the screw rod (62), and is used to The head (5) is fixed, and the screw rod (62) is arranged parallel to the length of the guide groove (61a). During the rotation of the screw rod (62), the screw nut (63) drives The pressure head (5) moves linearly along the guide groove (61a).
The ground push-type shear strength test device according to claim 1, wherein the clamp includes two clamping plates (7) for clamping both ends of the test piece, and the clamping plates (7) ) Movably arranged and moving along a straight line; further comprising at least two supporting plates (8) for supporting the periphery of the test piece and arranged at intervals, wherein at least one of the supporting plates (8) is movably arranged and connected to the clamp The tight plate (7) moves along the same straight line.
The ground-pushing shear strength test device according to claim 6, characterized in that the supporting part of the supporting plate (8) used to support the test piece includes a supporting part adapted to the surface of the test piece. At least one cushion structure

(81), the increase or decrease of the cushion structure (81) is used to adapt to the test pieces of various sizes, and each cushion structure (81) and the main body of the support plate (8) pass through a pressing block (9). )connection.
The ground-pushing shear strength test device according to claim 2, wherein the clamp includes two clamping blocks that are used to cover the periphery of the test piece and are symmetrically arranged at the part in contact with the test piece ( 10), the two clamping blocks (10) are movably arranged and move along a straight line; the end of the indenter (5) and the outer shape of the test piece are adapted to fit and set, and the side surface is aligned with one of the clamping blocks ( 10) The side fits.
The ground push type shear strength test device according to claim 1, wherein the heating and heat preservation system includes a power supply, a heating element, a temperature sensor, and a heat preservation box; the power supply is realized under the control of the control acquisition system The power supply and the control signal are turned on and off, the heating element is used to realize the temperature rise in the incubator, and the temperature sensor senses the temperature and feeds it back to the control acquisition system.
A ground-push type shear strength test method, which is characterized in that it comprises the following steps:

S1: Preparation or processing of test pieces;

S2: Install the test piece and keep it warm;

S3: Load until the specimen is destroyed;

S4: Calculate the shear strength=F/S, where S is the failure area.