CN112748029A - Semi-flexible asphalt concrete interface phase fretting fatigue test device and method - Google Patents
Semi-flexible asphalt concrete interface phase fretting fatigue test device and method Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0005—Repeated or cyclic
- G01N2203/0007—Low frequencies up to 100 Hz
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0026—Combination of several types of applied forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0073—Fatigue
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
Abstract
The invention relates to a semi-flexible asphalt concrete interface phase fretting fatigue test device and a method, which are used for carrying out fatigue test on a composite test piece, wherein the composite test piece comprises a cement block, asphalt and a stone block which are sequentially connected from top to bottom, the device comprises an MTS (maximum temperature differential) test machine, a monitoring terminal, a clamp and a base plate, the clamp comprises a test piece upper die and a test piece lower die, the composite test piece is clamped between the test piece upper die and the test piece lower die, the test piece lower die is obliquely arranged on the base plate through a wedge block, the base plate is provided with a shearing displacement measuring assembly and a fixed stopper, the wedge block is clamped between the fixed stopper and the test piece lower die, the shearing displacement measuring assembly comprises a linear differential strain sensor, the sensing tip of the linear differential strain sensor is contacted with the side surface. Compared with the prior art, the method can accurately and comprehensively measure the interface phase micro-motion effect and the fatigue performance of the semi-flexible asphalt concrete.
Description
Technical Field
The invention relates to the technical field of road engineering, in particular to a device and a method for testing fretting fatigue of a semi-flexible asphalt concrete interface phase.
Background
As a main form of roads in China, semi-rigid base asphalt pavements often cause diseases such as rutting and the like on channelized traffic road sections such as toll stations, parking lots and the like due to insufficient deformation resistance. The semi-flexible asphalt concrete is a composite material with flexible matrix and rigid intervention, which is prepared by filling cement mortar material into macroporous asphalt mixture as matrix. The semi-flexible asphalt concrete is mainly used for the surface layer of the road surface of a canalized traffic road section due to the characteristics of large modulus, long fatigue life, strong anti-rutting capability and the like, so that the road surface maintenance frequency and the maintenance workload are reduced, and good economic and social benefits are realized. Compared with the traditional asphalt concrete, the semi-flexible asphalt concrete has obvious interface phase formed by asphalt and cement mortar, and the interface phase can generate obvious interface behavior under the coupling action of load and environment, especially when the semi-flexible asphalt concrete generates fatigue cracking, the cracking always spreads along the interface of the mortar and the aggregate. The interface phase material is positioned between two interface pairs with higher rigidity, namely the aggregate and the cement gel, and bears the combined action of tensile stress, compressive stress and shear stress. Since the aggregate and cement gel are much stronger than the interfacial phase material, under repeated loading there is compression, tension and opposing movement between the two interfaces within, resulting in fatigue and wear, and thus failure may more easily propagate along the interfaces. According to the contact interface mechanics theory, the complex action of the interface phase in the semi-flexible asphalt concrete is called as the micro-motion effect, which can cause the performance of the interface phase material to change, generate fatigue damage and further develop into damage throughout the thickness direction of the semi-flexible asphalt concrete. Therefore, the research on the fretting fatigue effect of the semi-flexible asphalt concrete interface phase is of great significance.
In the existing interface fatigue test device in the civil engineering field, the fatigue characteristics of a steel-concrete interface and a new-old concrete interface are mainly researched, a horizontal or vertical load is applied through the driving of a servo hydraulic press, and a horizontal or vertical stress strain value is obtained through a stress strain sensor so as to evaluate the fatigue characteristics of the interface.
However, the existing interface fatigue device in China is still carried out based on the traditional unidirectional direct shearing device and additional fatigue load applying equipment, and the following problems exist:
1) the method is not suitable for fatigue test of the interface phase of the asphalt-cement mortar;
at present, an interface fatigue test device in the civil engineering field is mainly used for researching the fatigue property between two solid phases of steel-concrete or new and old concrete. However, asphalt and cement mortar are phase-change materials, asphalt has viscoelastic characteristics, cement mortar has fluidity at normal temperature, and although the asphalt and the cement mortar are often coagulated or hardened to form a state similar to a solid phase in a material characteristic test, the asphalt and the cement mortar are still in non-solid phase contact at an interface phase when the interface fatigue characteristic is researched, and a fatigue test device with solid phase contact is not suitable for fatigue test of an asphalt-cement mortar interface phase;
2) the loading direction of the interface is single and unreal;
the interface phase of the asphalt-cement mortar is positioned in a composite material system of semi-flexible asphalt concrete, and under the action of vehicle load, the load direction of the interface phase is not fixed and is not 0-degree or 90-degree load fixed by a traditional device, so that two combined stresses of tensile stress and shear stress can be decomposed on the interface instead of a single-direction stress mode;
3) the fatigue load application period cannot simulate the micro-motion frequency generated by traffic load;
the load period applied by the existing interface fatigue test device is set by considering the service characteristics of concrete or steel, and is not suitable for simulating the frequency characteristic of the traffic load of semi-flexible asphalt concrete.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a device and a method for testing the fretting fatigue of the semi-flexible asphalt concrete interface phase, which can accurately and comprehensively measure the fretting effect and the fatigue performance of the semi-flexible asphalt concrete interface phase.
The purpose of the invention can be realized by the following technical scheme:
a semi-flexible asphalt concrete interface phase fretting fatigue test device is used for carrying out fatigue test on a composite test piece, the composite test piece comprises a cement block, asphalt and a stone block which are sequentially connected from top to bottom, the device comprises an MTS tester, a monitoring terminal, a clamp and a substrate, the clamp comprises a test piece upper die and a test piece lower die, the composite test piece is clamped between the test piece upper die and the test piece lower die, the lower die of the test piece is obliquely arranged on a base plate through a wedge block, the base plate is provided with a shearing displacement measuring component and a fixed stopper, the wedge block is clamped between the fixed stopper and the lower die of the test piece, the shear displacement measuring component comprises a linear differential strain sensor, the sensing tip of the linear differential strain sensor is in contact with the side face of the cement block in the inclined direction, and the MTS tester and the linear differential strain sensor are connected with the monitoring terminal;
the lower test piece die is bonded with the lower test piece die and the upper test piece die through epoxy asphalt, so that relative sliding is avoided, and the reliability and accuracy of a test result are ensured;
the composite test piece can simulate a semi-flexible asphalt concrete interface phase, the composite test piece is restrained through the test piece upper die and the test piece lower die, the composite test piece is locally loaded through the test piece upper die, the stress condition of the semi-flexible asphalt concrete interface phase can be truly simulated, the inclination angle of the composite test piece is adjusted through the wedge block, the inclination angle of the semi-flexible asphalt concrete interface phase is further adjusted, various stress conditions are simulated, and the test result is more comprehensive.
Further, the test piece upper die comprises a pull-shear test piece upper die or a press-shear test piece upper die.
Furthermore, the compression shear test piece upper die comprises a first base plate, a first baffle and a pressurizing plate, two sides of the first base plate are respectively contacted with the pressurizing plate and the cement block, the first baffle is vertically arranged on the first base plate and is contacted with the side face of the cement block back to the inclined direction, a loading pressure head of the MTS test machine is contacted with the pressurizing plate during testing, and the pressurizing plate is rectangular and horizontally arranged, so that the loading pressure head can be conveniently pressurized.
Furthermore, the pull-shear test piece upper die comprises a clamping block and a clamping piece on the clamping block, a clamping groove matched with the composite test piece is formed in the clamping block, the cement block is inserted into the clamping groove, and a loading pressure head of the MTS test machine is connected with the clamping piece during testing.
Furthermore, the clamping piece is a sleeve with an internal thread, and a loading pressure head of the MTS testing machine is connected with the sleeve through a threaded rod in a threaded manner, so that the MTS testing machine is convenient to disassemble and assemble.
Furthermore, the test piece lower die comprises a second bottom plate and a second baffle plate vertically arranged on the second bottom plate, the second baffle plate is in contact with the side face of the stone block in the inclined direction, and two sides of the second bottom plate are in contact with the stone block and the wedge block respectively.
Further, the test piece upper die and the test piece lower die are made of copper.
The shearing displacement measuring assembly further comprises an angle adjusting rod, a support and a semicircular protractor, wherein the end part of the angle adjusting rod and the circle center of the protractor are coaxially fixed on the support through a bolt and a nut, and the linear differential strain sensor is arranged on the angle adjusting rod;
the linear differential strain sensor adopts a light iron core and a stainless steel shell, the measuring range is +/-30.0 mm, the nonlinearity is better than +/-0.25% FRO, and the sealing grade is IEC IP-61;
the angle adjusting rod is provided with a positioning line in the same direction as the angle adjusting rod, the range of the protractor is 0-180 degrees, and the minimum scale is 0.1 degree;
the angle adjusting rod is provided with a threaded through hole, the linear differential strain sensor is hinged to the angle adjusting rod through a nut and a bolt penetrating through the threaded through hole, and the angle adjusting rod is embedded on the substrate to ensure that relative displacement cannot occur.
Furthermore, the wedge block is made of iron, the wedge blocks are various in types, the inclination angles of the wedge blocks are different, the number of the wedge blocks is 1 or more, the inclination angles of the test piece lower die can be adjusted in a grading mode by combining the wedge blocks with different inclination angles, and the angle of the composite test piece is further adjusted.
Furthermore, the fixed stopper comprises a limiting bolt, a limiting steel plate and an embedding plate, wherein the limiting steel plate and the embedding plate are vertically arranged on the base plate, the wedge is abutted against the limiting steel plate, the wedge for adjusting the angle is guaranteed not to slide, the embedding plate is embedded into the base plate, a connecting rod is vertically arranged on the limiting steel plate, a limiting hole is formed in the embedding plate, the end part of the connecting rod penetrates through the limiting hole, an internal thread hole is formed in the end part of the connecting rod, the limiting bolt is screwed into the internal thread hole, the assembly and disassembly are simple and convenient, the interval between the limiting steel plate 81 and the embedding plate 84 is guaranteed not to change during the test, and the limiting effect is achieved.
A test method using the test apparatus according to claim 1, specifically comprising:
the method comprises the following steps that a base plate, a lower test piece die, a composite test piece and an upper test piece die are sequentially erected, the inclination angle of the lower test piece die is adjusted through a wedge block, the wedge block is fixed in position through a fixed stopper, the sensing tip of a linear differential strain sensor is in contact with the side face, facing the inclination direction, of a cement block, and a monitoring terminal displays the load value collected by a load sensor in an MTS (maximum temperature stress) testing machine and the displacement of the cement block collected by the linear differential strain sensor in real time to perform a fatigue test;
the fatigue test comprises a compression shear test and a tension shear test;
the compression shear test specifically comprises the following steps:
adjusting a loading pressure head of the MTS test machine to enable the loading pressure head to just contact the test piece upper die, zeroing the load value and the displacement displayed by the monitoring terminal, controlling the loading pressure head of the MTS test machine to apply dynamic pressure to the test piece upper die through the monitoring terminal, judging that the interface phase is damaged when the sudden increase or the sudden decrease of the load value is met, and ending the test;
the pulling and shearing test specifically comprises the following steps:
fixing a loading pressure head of the MTS testing machine with an upper die of the test piece, moving the sensing tip towards the cement block for a set distance, zeroing the load value and displacement displayed by the monitoring terminal, controlling the loading pressure head of the MTS testing machine to apply dynamic tension to the upper die of the test piece through the monitoring terminal, judging that the interface is damaged when sudden increase of displacement or sudden decrease of the load value is met, and ending the test.
Compared with the prior art, the invention has the following beneficial effects:
(1) the composite test piece comprises a cement block, asphalt and stones which are sequentially arranged from top to bottom, can simulate a semi-flexible asphalt concrete interface phase, is restrained by a test piece upper die and a test piece lower die, the inclination angle of the composite test piece is adjusted by a wedge block, and a tensile force or a pressure is applied to the test piece upper die by an MTS (maximum temperature stress) testing machine, so that the stress condition of the semi-flexible asphalt concrete interface phase can be really simulated;
(2) the invention can respectively carry out two fatigue tests, namely a compression shear test and a tension shear test, through the tension shear test piece upper die or the compression shear test piece upper die, and meanwhile, various fatigue tests have two ending judgment bases of displacement or load value, so that 4 test functions are realized, and the application range is wide;
(3) the test piece upper die comprises a pull-shear test piece upper die or a press-shear test piece upper die, the press-shear test piece upper die comprises a first bottom plate, a first baffle and a pressurizing plate, the first baffle and the pressurizing plate are arranged on the first bottom plate, two sides of the first bottom plate are respectively contacted with the bottom surface and the wedge block of the composite test piece, the first baffle is vertically arranged on the first bottom plate and is contacted with the side surface of the back of the composite test piece in the inclined direction, a loading pressure head of an MTS test machine is contacted with the pressurizing plate during test, the pull-shear test piece upper die comprises a clamping block and a clamping piece on the clamping block, a clamping groove matched with the composite test piece is arranged on the clamping block, the composite test piece is inserted into the clamping groove, the loading pressure head of the MTS test machine is fixedly connected with the clamping piece during test, the test piece lower die comprises a second bottom plate and a second baffle vertically arranged on the second bottom, the upper test piece die and the lower test piece die can respectively restrain the upper end and the lower end of the composite test piece, so that the tension/pressure applied to the composite test piece by the MTS testing machine in the test process is kept stable, the structure is simple, and the installation is simple and convenient;
(4) according to the invention, the shearing displacement measuring assembly also comprises an angle adjusting rod, a support and a semicircular protractor, wherein the end part of the angle adjusting rod and the circle center of the protractor are coaxially fixed on the support through a bolt and a nut, the linear differential strain sensor is arranged on the angle adjusting rod, and the protractor can be accurately adjusted along with the change of the inclination angle of the composite test piece, so that the angle of the linear differential strain sensor is accurately controlled, the shearing displacement of the composite test piece is accurately measured, and the accurate decomposition of the inclination angle during the test is realized;
(5) the wedge block type test bed has various wedge blocks, the inclination angles of the various wedge blocks are different, the number of the various wedge blocks (7) is 1 or more, the inclination angles of the composite test piece can be regulated in a grading manner, and the operation is simple and convenient;
(6) the fixed stopper comprises a limiting bolt, a limiting steel plate and an embedding plate, wherein the limiting steel plate and the embedding plate are vertically arranged on a base plate, a wedge block abuts against the limiting steel plate, the embedding plate is embedded into the base plate, a connecting rod is vertically arranged on the limiting steel plate, a limiting hole is formed in the embedding plate, the end part of the connecting rod penetrates through the limiting hole, an internal threaded hole is formed in the end part, the limiting bolt is screwed into the internal threaded hole, and the distance between the embedding plate and the limiting steel plate is kept unchanged, so that the limiting steel plate can limit the wedge block, a composite test piece is prevented from moving during testing, and the disassembly and the.
Drawings
FIG. 1 is a schematic view of the structure of the present invention in a compression shear test;
FIG. 2 is a schematic of the structure of a shear displacement measurement assembly;
FIG. 3 is a structural schematic of a composite test piece;
FIG. 4 is a structural schematic of a fixed stop;
FIG. 5 is a force diagram of a composite test piece;
FIG. 6 is a schematic of the structure of the present invention during a pull shear test;
FIG. 7 is a structural schematic of an upper die of the tension-shear test piece;
FIG. 8 is a structural schematic of an upper die of a compression shear test piece;
FIG. 9 is a structural schematic of a lower die of a test piece;
the reference numbers in the figures illustrate:
1. the device comprises a pull-shear test piece upper die, a press-shear test piece upper die, a composite test piece 3, a base plate 4, a shear displacement measuring assembly 5, a vertical fixing rod 56, a test piece lower die 6, a wedge block 7, a fixed stopper 8, a clamping piece 11, a clamping piece 12, a clamping block 21, a first bottom plate 22, a first baffle plate 23, a pressure plate 31, a cement block 32, asphalt 33, a stone block 51, a linear differential strain sensor 52, a bracket 52, an angle adjusting rod 53, an angle gauge 54, a protractor 61, a second bottom plate 62, a second baffle plate 81, a limiting steel plate 82, a connecting rod 83, a limiting bolt 84, an embedded fixing plate 84, a clamping groove 121 and an induction tip 511.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Example 1
A semi-flexible asphalt concrete interface phase fretting fatigue test device is used for carrying out fatigue test on a composite test piece 3, the composite test piece 3 comprises a cement block 31, asphalt 32 and a stone block 33 which are sequentially connected from top to bottom, the device is shown in figures 1 and 3 and comprises an MTS test machine, a monitoring terminal, a clamp and a base plate 4, the clamp comprises a test piece upper die and a test piece lower die 6, the composite test piece 3 is clamped between the test piece upper die and the test piece lower die 6, the test piece lower die 6 is obliquely arranged on the base plate 4 through a wedge 7, the base plate 4 is provided with a shearing displacement measuring assembly 5 and a fixed stopper 8, the wedge 7 is clamped between the fixed stopper 8 and the test piece lower die 6, the shearing displacement measuring assembly 5 comprises a linear differential strain sensor 51, a sensing tip 511 of the linear differential strain sensor 51 is in contact with the side face of the cement block 31 facing the oblique direction, the MT, the monitoring terminal adopts a high-performance computer;
the lower test piece die 6 is bonded with the lower test piece die 6 and the upper test piece die through epoxy asphalt, so that relative sliding cannot occur, the tensile/compressive stress and the shear stress decomposed on an interface are more accurate, and the reliability and the accuracy of a test result are ensured;
the composite test piece 3 can simulate a semi-flexible asphalt concrete interface phase, the composite test piece 3 is restrained through the test piece upper die and the test piece lower die 6, the composite test piece 3 is locally loaded through the test piece upper die, the stress condition of the semi-flexible asphalt concrete interface phase can be truly simulated, the inclination angle of the composite test piece 3 is adjusted through the wedge block 7, the inclination angle of the semi-flexible asphalt concrete interface phase is further adjusted, various stress conditions are simulated, and the test result is more comprehensive.
The preparation process of the composite test piece 3 is as follows:
coating hot asphalt on a cuboid stone block with the size of 30mm multiplied by 20mm, cooling at room temperature, putting the cuboid stone block into a cuboid preparation test mould with the inner wall coated with lubricating oil after cooling, wherein the internal size of the preparation test mould is 30mm multiplied by 42mm multiplied by 20mm, and enabling the cuboid stone block to be in close contact with the bottom of the preparation test mould;
preparing cement paste by adopting a cement paste mixer, detecting the fluidity of the cement paste by adopting an inverted cone method, filling the qualified cement paste into a preparation test mold for one time until the cement paste is filled, placing the preparation test mold on a vibration table for vibration for 60 times, scraping cement exceeding the opening of the preparation test mold by using a scraper after the vibration is finished, curing for 72 hours in a curing box, demolding, and sticking a label to finish the preparation of the composite test piece 3.
The test piece upper die comprises a pull-shear test piece upper die 1 or a press-shear test piece upper die 2.
As shown in fig. 8, the upper die 2 of the compression shear test piece comprises a first base plate 21, a first baffle plate 22 and a pressure plate 23, two sides of the first base plate 21 are respectively contacted with the pressure plate 23 and the cement block 31, the first baffle plate 22 is vertically arranged on the first base plate 21 and is contacted with the side surface of the cement block 31 facing away from the inclined direction, a loading pressure head of the MTS tester is contacted with the pressure plate 23 during the test, and the pressure plate 23 is rectangular and has the size of 40mm × 30mm, so that the MTS tester can be conveniently pressurized.
The tension-shear test piece upper die 1 comprises a clamping block 12 and a clamping piece 11 on the clamping block 12, a clamping groove 121 matched with the composite test piece 3 is formed in the clamping block 12, the cement block 31 is inserted into the clamping groove 121, and a loading pressure head of an MTS testing machine is connected with the clamping piece 11 during testing.
The clamping piece 11 is a sleeve with an internal thread, the length is 20mm, the outer diameter is 15mm, and a loading pressure head of the MTS test machine is in threaded connection with the sleeve through a threaded rod, so that the assembly and disassembly are convenient;
as shown in fig. 9, the lower mold 6 includes a second base plate 61 and a second stopper 62 vertically disposed on the second base plate 61, the second stopper 62 contacts with the side of the block 33 facing the inclined direction, and both sides of the second base plate 61 contact with the block 33 and the wedge 7, respectively.
The upper test piece die and the lower test piece die 6 are made of copper, have good ductility and are not easy to damage.
As shown in fig. 2, the shear displacement measuring assembly 5 further includes an angle adjusting rod 53, a bracket 52 and a semicircular protractor 54, wherein the end of the angle adjusting rod 53 and the center of the protractor 54 are coaxially fixed on the bracket 52 by a bolt and a nut, and the linear differential strain sensor 51 is arranged on the angle adjusting rod 53;
the linear differential strain sensor 51 adopts a light iron core and a stainless steel shell, the measuring range is +/-30.0 mm, the nonlinearity is better than +/-0.25% FRO, and the sealing grade is IEC IP-61;
the angle adjusting rod 53 is provided with a positioning line in the same direction as the angle adjusting rod, the range of the protractor 54 is 0-180 degrees, and the minimum scale is 0.1 degree;
the angle adjusting rod 53 is provided with a threaded through hole, the linear differential strain sensor 51 is hinged on the angle adjusting rod 53 through a nut and a bolt penetrating through the threaded through hole, and the angle adjusting rod 53 is embedded on the substrate 4 to ensure that relative displacement cannot occur.
The wedge 7 is made of iron, the types of the wedges 7 are various, the inclination angles of the wedges 7 are different, the number of the wedges 7 is 1 or more, the wedges 7 with different inclination angles are used in combination, the inclination angle of the test piece lower die 6 can be adjusted in a grading mode, and the angle of the composite test piece 3 is further adjusted. The worst stress state of the road surface layer is simulated, namely the inclination angle theta corresponding to the horizontal force coefficient of 0.5 is 26 degrees 34', based on an Odemark model, the load is assumed to be linearly diffused in semi-flexible asphalt concrete, the inclination angle corresponding to the worst stress state of the interface phase is close to 26 degrees, the inclination angle of the composite test piece 3 is adjusted through the wedge 7, the measurable angle range of the device is 10 degrees to 50 degrees, and therefore the angle grading adjustment is carried out by adopting the two wedges 7 with the inclination angles of 10 degrees and 15 degrees respectively.
As shown in fig. 4, the fixed stopper 8 includes a limiting bolt 83, and a limiting steel plate 81 and an embedding plate 84 vertically disposed on the substrate 4, the size of the limiting steel plate 81 is 40mm × 40mm × 10mm, the wedge 7 abuts against the limiting steel plate 81 to ensure that the wedge 7 for adjusting the angle does not slide, the embedding plate 84 is embedded in the substrate 4, the limiting steel plate 81 is vertically provided with a connecting rod 82, the embedding plate 84 is provided with a limiting hole, the end of the connecting rod 82 passes through the limiting hole, the end is provided with an internal threaded hole, the limiting bolt 83 is screwed into the internal threaded hole, the assembly and disassembly are simple, the spacing between the limiting steel plate 81 and the embedding plate 84 is ensured not to change during the test, and the limiting function is achieved.
Example 2
The fretting fatigue test method of the semi-flexible asphalt concrete interface phase corresponding to the embodiment 1 specifically comprises the following steps:
as shown in fig. 1, a substrate 4, a test piece lower die 6, a composite test piece 3 and a compression shear test piece upper die 2 are sequentially erected, wherein the test piece lower die 6 is bonded with the test piece lower die 6 and the test piece upper die through epoxy asphalt, the inclination angle of the test piece lower die 6 is adjusted by combining wedges 7 with different inclination angles, the wedge 7 abuts against a limiting steel plate 81, a sensing tip 511 of a linear differential strain sensor 51 is contacted with the side face of a cement block 31 in the inclination direction, a monitoring terminal displays a load value acquired by a load sensor in an MTS testing machine and the displacement of the cement block 31 acquired by the linear differential strain sensor 51 in real time, and a compression shear test is carried out;
the compression shear test specifically comprises the following steps:
adjusting a loading pressure head of the MTS tester to just contact the pressurizing plate 23, zeroing a load value and displacement displayed by the monitoring terminal at the moment, setting a dynamic load and stress control rate, wherein the load is loaded by adopting a half-sine vector wave, the loading frequency is 10Hz, controlling the loading pressure head of the MTS tester to apply dynamic pressure P to the pressurizing plate 23, as shown in FIG. 5, the inclination angle of the pressurizing plate 23 is theta, the pressure stress and the shear stress generated by P are respectively sigma and tau, tau can enable the cement block 31 to generate shear displacement, and when the displacement displayed by the monitoring terminal is suddenly increased, judging that an interface phase is damaged, and ending the test.
Example 3
In this embodiment, when the load value displayed by the monitoring terminal suddenly drops, it is determined that the interface phase is broken, and the test is ended, the other steps are the same as those in embodiment 2.
Example 4
In the embodiment, a substrate 4, a test piece lower die 6, a composite test piece 3 and a pull-shear test piece upper die 1 are sequentially erected to perform a pull-shear test;
the pulling and shearing test specifically comprises the following steps:
as shown in fig. 6, a loading pressure head of the MTS testing machine is in threaded connection with a clamping piece 11 of a pull-shear test piece upper die 1;
the sensing tip 511 is moved towards the cement block 31 for a set distance, the load value and the displacement displayed by the monitoring terminal are zeroed, the loading pressure head of the MTS testing machine is controlled by the monitoring terminal to apply dynamic tension to the upper die of the test piece, when the displacement displayed by the monitoring terminal is suddenly increased, the interface is judged to be damaged, the test is ended, and the rest is the same as that of the embodiment 2.
Example 5
In this embodiment, when the load value displayed by the monitoring terminal suddenly drops, it is determined that the interface phase is broken, and the test is ended, the other steps are the same as those in embodiment 4.
The embodiment 1, the embodiment 2, the embodiment 3, the embodiment 4 and the embodiment 5 provide a device and a method for testing the fretting fatigue of the semi-flexible asphalt concrete interface phase, the stress condition of the semi-flexible asphalt concrete interface phase can be truly simulated by adopting a local loading and test mode restraining mode, and the fretting effect and the fatigue performance of the semi-flexible asphalt concrete interface phase can be measured;
can carry out two kinds of fatigue tests through respectively on the pull shear test piece mould or the press shear test piece mould, press shear test and pull shear test promptly, various fatigue tests have displacement or load value these two kinds of completion judgement foundation simultaneously, thereby realize 4 kinds of test functions, the range of application is wide, the size of mould on the test piece is far more than the aggregate particle size in the composite test piece simultaneously, the error that size effect produced can be avoided, simultaneously the inclination of composite test piece is adjusted in grades to accessible voussoir 7, simultaneously through angle adjusting lever 53 protractor 54 accuracy, correspondingly adjust the angle of linear differential strain sensor 51, can the precision, survey semi-flexible asphalt concrete interface fine motion looks micro-motion effect and fatigue property comprehensively, the test result reliability is high.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (10)
1. The semi-flexible asphalt concrete interface phase fretting fatigue test device is characterized by being used for carrying out fatigue test on a composite test piece (3), wherein the composite test piece (3) comprises a cement block (31), asphalt (32) and a stone block (33) which are sequentially connected from top to bottom, the device comprises an MTS test machine, a monitoring terminal, a clamp and a base plate (4), the clamp comprises a test piece upper die and a test piece lower die (6), the composite test piece (3) is clamped between the test piece upper die and the test piece lower die (6), the test piece lower die (6) is obliquely arranged on the base plate (4) through a wedge block (7), the base plate (4) is provided with a shearing displacement measuring assembly (5) and a fixed stopper (8), the wedge block (7) is clamped between the fixed stopper (8) and the test piece lower die (6), the shearing displacement measuring assembly (5) comprises a linear differential strain sensor (51), the sensing tip (511) of the linear differential strain sensor (51) is in contact with the side face, facing the inclined direction, of the cement block (31), and the MTS testing machine and the linear differential strain sensor (51) are connected with a monitoring terminal.
2. The device for testing the fretting fatigue of the semi-flexible asphalt concrete interface phase according to claim 1, wherein the test piece upper die comprises a pulling and shearing test piece upper die (1) or a pressing and shearing test piece upper die (2).
3. The device for testing the fretting fatigue of the semi-flexible asphalt concrete interface according to claim 2, wherein the upper die (2) of the compression shear test piece comprises a first bottom plate (21), a first baffle plate (22) and a pressurizing plate (23), two sides of the first bottom plate (21) are respectively contacted with the pressurizing plate (23) and the cement block (31), the first baffle plate (22) is vertically arranged on the first bottom plate (21) and is contacted with the side surface of the cement block (31) back to the inclined direction, and a loading pressure head of the MTS testing machine is contacted with the pressurizing plate (23) during the test.
4. The device for testing the fretting fatigue of the semi-flexible asphalt concrete interface according to claim 2, wherein the upper die (1) of the pull-shear test piece comprises a clamping block (12) and a clamping piece (11) arranged on the clamping block (12), a clamping groove (121) matched with the composite test piece (3) is arranged on the clamping block (12), the cement block (31) is inserted into the clamping groove (121), and a loading pressure head of an MTS testing machine is connected with the clamping piece (11) during testing.
5. The device for testing fretting fatigue of semi-flexible asphalt concrete interface according to claim 4, wherein the clamping member (11) is a sleeve with internal threads.
6. The device for testing the fretting fatigue of the interface phase of the semi-flexible asphalt concrete according to claim 1, wherein the lower die (6) of the test piece comprises a second bottom plate (61) and a second baffle plate (62) vertically arranged on the second bottom plate (61), the second baffle plate (62) is in contact with the side surface of the stone block (33) facing the inclined direction, and two sides of the second bottom plate (61) are in contact with the stone block (33) and the wedge block (7) respectively.
7. The device for testing the interfacial fretting fatigue of semi-flexible asphalt concrete according to claim 1, wherein the shear displacement measuring assembly (5) further comprises an angle adjusting rod (53), a bracket (52) and a semicircular protractor (54), wherein the end of the angle adjusting rod (53) and the center of the protractor (54) are coaxially fixed on the bracket (52) through a bolt and a nut, and the linear differential strain sensor (51) is arranged on the angle adjusting rod (53).
8. The device for testing fretting fatigue of semi-flexible asphalt concrete interface phase according to claim 1, wherein the wedge (7) is of various types, the inclination angles of the various wedges (7) are different, and the number of the various wedges (7) is 1 or more.
9. The device for testing the fretting fatigue of the semi-flexible asphalt concrete interface phase according to claim 1, wherein the fixed stopper (8) comprises a limit bolt (83), a limit steel plate (81) and an embedding plate (84) which are vertically arranged on the base plate (4), the wedge block (7) abuts against the limit steel plate (81), the embedding plate (84) is embedded in the base plate (4), a connecting rod (82) is vertically arranged on the limit steel plate (81), a limit hole is arranged on the embedding plate (84), the end part of the connecting rod (82) passes through the limit hole, an internal threaded hole is arranged at the end part, and the limit bolt (83) is screwed into the internal threaded hole.
10. A test method using the test apparatus according to claim 1, characterized in that:
the method comprises the following steps that a base plate (4), a test piece lower die (6), a composite test piece (3) and a test piece upper die are sequentially erected, the inclination angle of the test piece lower die (6) is adjusted through a wedge block (7), the wedge block (7) is fixed in position through a fixing stopper (8), a sensing tip (511) of a linear differential strain sensor (51) is in contact with the side face, facing the inclination direction, of a cement block (31), and a monitoring terminal displays a load value collected by a load sensor in an MTS testing machine and displacement of the cement block (31) collected by the linear differential strain sensor (51) in real time to perform fatigue testing;
the fatigue test comprises a compression shear test and a tension shear test;
adjusting a loading pressure head of the MTS testing machine to enable the loading pressure head to just contact the test piece upper die, zeroing the load value and displacement displayed by the monitoring terminal, controlling the loading pressure head of the MTS testing machine to apply dynamic pressure to the test piece upper die through the monitoring terminal, judging that an interface phase is damaged when set conditions are met, and finishing the test;
the setting conditions are as follows: sudden increase in displacement or sudden decrease in load value;
the pulling and shearing test specifically comprises the following steps:
fixing a loading pressure head of the MTS testing machine with a test piece upper die, moving the induction tip (511) towards the cement block (31) for a set distance, zeroing the load value and displacement displayed by the monitoring terminal, controlling the loading pressure head of the MTS testing machine to apply dynamic tension to the test piece upper die through the monitoring terminal, judging that the interface is damaged when the load value suddenly drops, and ending the test.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113310800A (en) * | 2021-05-14 | 2021-08-27 | 扬州大学 | Asphalt and cement mortar interface tensile strength testing device and testing method |
| CN113686681A (en) * | 2021-09-06 | 2021-11-23 | 广州大学 | Drawing test device and method for fibers with different embedding angles and embedding lengths |
| CN114112630A (en) * | 2021-11-17 | 2022-03-01 | 洛阳双瑞特种装备有限公司 | Test device and method for measuring horizontal performance of rubber support in vertical loading mode |
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- 2021-01-22 CN CN202110091269.5A patent/CN112748029A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113310800A (en) * | 2021-05-14 | 2021-08-27 | 扬州大学 | Asphalt and cement mortar interface tensile strength testing device and testing method |
| CN113686681A (en) * | 2021-09-06 | 2021-11-23 | 广州大学 | Drawing test device and method for fibers with different embedding angles and embedding lengths |
| CN114112630A (en) * | 2021-11-17 | 2022-03-01 | 洛阳双瑞特种装备有限公司 | Test device and method for measuring horizontal performance of rubber support in vertical loading mode |
| CN114112630B (en) * | 2021-11-17 | 2023-09-15 | 中船双瑞(洛阳)特种装备股份有限公司 | Test device and method for measuring horizontal performance of rubber support in vertical loading mode |
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