CN203025044U - Bituminous mixture triaxial test device - Google Patents

Bituminous mixture triaxial test device Download PDF

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Publication number
CN203025044U
CN203025044U CN 201220739581 CN201220739581U CN203025044U CN 203025044 U CN203025044 U CN 203025044U CN 201220739581 CN201220739581 CN 201220739581 CN 201220739581 U CN201220739581 U CN 201220739581U CN 203025044 U CN203025044 U CN 203025044U
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China
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air bag
interior air
sleeve
interior
test specimen
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CN 201220739581
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Chinese (zh)
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郑健龙
钱国平
黄拓
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长沙理工大学
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Priority to CN 201220739581 priority Critical patent/CN203025044U/en
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Abstract

The utility model discloses a bituminous mixture triaxial test device which comprises a material test specification (MTS) material tester, an external air bag component, an internal air bag component, an upper pressing plate, a lower pressing plate and an air pressure control console, wherein an external air bag of the external air bag component is arranged on the outer side of a test piece and wraps the outer side surface of the test piece; an internal air bag of the internal air bag component is arranged in an inner hole of the test piece and is in tight contact with the surface of the inner hole of the test piece; the air pressure control console can supply stable air pressure to the internal air bag component and the external air bag component; the upper pressing plate and the lower pressing plate are respectively fixed on the upper surface and the lower surface of the test piece; the lower pressing plate is connected with a supporting seat of the MTS material tester; and the upper pressing plate is connected with a telescopic arm of the MTS material tester. By a rigid and flexible composite loading mode, the bituminous mixture triaxial test device is easy to control and can avoid the corner effect at a corner of a conventional cubic triaxial test piece. By the bituminous mixture triaxial test device, the problem that the conventional bituminous mixture triaxial test device is not suitable for bituminous mixtures is solved, and the bituminous mixture intensity research field is expanded from a one-dimensional stressed state to a three-directional stressed state; and the bituminous mixture triaxial test device provided by the utility model has great significance for research on the mechanical property of the bituminous mixture in a complicated stressed state, design of the bituminous mixture and prevention and control of damage to a bituminous pavement.

Description

A kind of asphalt Triaxial tester

Technical field

The utility model belongs to the road engineering field, is specially a kind of asphalt Triaxial tester.

Background technology

By the end of the year 2012, the built highway that is open to traffic of China occupies the second place of the world, is wherein bituminous pavement more than 90%.In the construction process of Asphalt Pavement of Highway, the road worker has solved a large amount of technical barriers, has accumulated abundant practical experience.But from the bituminous pavement behaviour in service that has put into effect in recent years, many asphalt pavement structures do not reach and designed life just occurred disease in various degree, have caused huge economic loss and bad social influence.Particularly in recent years, the significantly increase of overload heavy-duty vehicle makes bituminous pavement in use can run into various destructions and damage.In research during these problems, the strength problem research under load action is the basis of various destruction Study on Problems.

For a long time, the research of asphalt strength characteristics is the hot issue that domestic and international road worker is concerned about always, but the strength test of existing asphalt mostly is uniaxial test, rarely has the research about the asphalt multi-shaft strength.The Strength Testing Methods that is used for evaluation asphalt mechanical property in " highway asphalt and Asphalt Mixture Experiment rules " has: (1) bending test, (2) uniaxial compression test, (3) diametral compression test, (4) triaxial shear test.Bending test, uniaxial compression test and diametral compression test are the uniaxial test method, can't simulate the triaxial stress state of asphalt under actual condition.The asphalt ordinary triaxial test is the triaxial test that two principle stresses equate, its process of the test is: be placed in the pressure chamber after with rubber membrane, test specimen being wrapped up, by pressurized air, test specimen applied confined pressure, make test specimen be in σ 123cStress state, then apply axial compression by piston, make test specimen axially produce the poor failure of deviatoric stress.Because test piece end is wrapped up by rubber diaphragm, be difficult to and load the axle bonding, also just can't carry out the triaxial extension test of asphalt.In fact, existing asphalt ordinary triaxial test method only can be hanged down three axial compression contracting failure tests under confined pressure, and the greatest drawback of this test method is can't inner form stress state that three principle stresses do not wait at test specimen, can not reflect that intermediate principal stress is on the impact of the strength of materials.Under the effect of wheel load, bituminous concrete is in obvious multi-axis stress state, the three-dimensional principle stress that it bears does not wait, and may be the various combination of compressive stress or tension, existing ordinary triaxial test method obviously can not reflect the mechanical characteristic of asphalt under actual operating conditions.

With regard to test apparatus method and test apparatus, existing triaxial test method utilizes triaxial tester from three principal directions of stress, cuboid sample to be loaded more, with the mechanical characteristic of material under the reflection complex stress condition.Since Kjellman in 1936 successfully designs true triaxil tester, successively developed multiple True Triaxial Apparatus both at home and abroad.Institute of Hydro-Technical Research of China Ministry of Water Resources and Electric Power, Tsing-Hua University, Tongji University, Hohai University, Dalian University of Technology, Wuhan rock-soil mechanics research institute develop multiaxis stress test device since the eighties in 20th century, have obtained effect preferably.According to the mode that applies of intermediate principal stress, triaxial tester generally can be divided into " rigidity load mode ", " flexible load mode ", " combination of rigidity and flexibility load mode " three types.Relative stiffness load mode and flexible load mode, the triaxial tester of compound loading mode is easy to control, and existing True Triaxial Apparatus mostly is the combined type load mode.

But also there are some defectives in the True Triaxial Apparatus that adopts cube to load:

(1) there is defective in the load mode of true triaxil tester.In to cube specimen three-dimensional loading procedure, there is between the rigidity load plate problem of phase mutual interference between the distortion of restriction mutually, rigid plate constraint test specimen and towed flexible barge.In order to address this problem, usually be reserved with the space with the mutual extruding between increased pressure board in avoiding process of the test between vertical increased pressure board and horizontal increased pressure board, but the inhomogeneous stress and strain (namely producing the corner effect) of generation in sample can be caused in the space of reserving, and affects the accuracy of test findings.

(2) existing True Triaxial Apparatus is not suitable for asphalt.At present, the true triaxil tester of exploitation mainly is applicable to rock-soil material both at home and abroad.Generally, the maximum crushing stress that geotechnique's triaxial tester applies is 3-5MPa, and the compressive strength of AC-13 type asphalt in the time of 20 ℃ can reach 6MPa, if reduce test temperature or adopt thicker grating, the compressive strength of asphalt can further increase.Obviously, geotechnological triaxial tester range is less than normal for asphalt, can't make the asphalt failure.And the stress that rock triaxial test instrument minor principal stress direction applies is the 100MPa left and right, and the stress that large principal direction of stress can apply is the 800MPa left and right, if be 1% calculating by precision, its test error is 8MPa, surpasses the uniaxial compressive strength of asphalt.Obviously, for asphalt, rock true triaxial test machine range is bigger than normal, precision is on the low side, error is excessive.In fact, the Material Testing Machine that different material requires is different, in order to study the mechanical property of ice, American MTS company has researched and developed a kind of true triaxial test machine and control system of suitable ice specially.

(3) existing true triaxial test machine is not easy to apply.The design True Triaxial Apparatus is all higher to the requirement of Machinery Design, propulsion system, test specimen processing, testing element, thereby causes the development of three-axis tester to have length consuming time, cost is large, technical difficulty is high, risk is large characteristics.As certain unit development concrete Triaxial tester, went through more than ten years front and back, has employed a large amount of human and material resources, financial resources.Due to the R﹠D process of triaxial tester very complicated and the cycle long, expensive, be difficult to apply on a large scale.Be subject to the restriction of technical factor and other aspect, not yet develop the Triaxial tester that is suitable for asphalt both at home and abroad, this has become the bottleneck of restriction asphalt strength characteristics research.

The utility model content

The purpose of this utility model be for the deficiencies in the prior art provide a kind of simple, with low cost, be convenient to promote, be suitable for asphalt and can avoid the asphalt Triaxial tester of traditional triaxial apparatus corner effect.

The utility model is achieved through the following technical solutions above-mentioned purpose:

a kind of asphalt Triaxial tester, comprise the gentle pressure-controlled platform of MTS Material Testing Machine, also comprise outer air bag component, interior air bag component, top board and lower platen, described outer air bag component and interior air bag component provide adjustable air pressure by described air pressure control desk, the outer air bag of described outer air bag component is arranged on the outside of hollow circular cylinder test specimen and wraps up the outer cylinder surface of described hollow circular cylinder test specimen, the interior air bag of described interior air bag component be arranged in the endoporus of hollow circular cylinder test specimen and with described hollow circular cylinder test specimen endoporus close contact, described top board and lower platen are separately fixed at upper surface and the lower surface of described hollow circular cylinder test specimen, described lower platen is connected with described MTS Material Testing Machine supporting seat, described top board is connected with the telescopic arm of described MTS Material Testing Machine.

described outer air bag component comprises sleeve, the air bag pressing plate, outer air bag and screw rod, described sleeve surface is provided with the air intake opening that is communicated with the outside in described sleeve, described sleeve comprises upper bush and lower sleeve, described upper bush and lower sleeve sealed card are fitted together, described outer air bag rubber diaphragm is hollow cylinder, the diameter of the film formed hollow cylinder of described outer air bag rubber is equal to or greater than the diameter of hollow circular cylinder test specimen, the two ends that described outer air bag rubber diaphragm is placed on described sleeve inboard and described outer air bag rubber diaphragm are installed on described sleeve two ends and are fixed by described air bag pressing plate, fix by screw rod between the described air bag pressing plate of described sleeve upside and downside, make described air bag pressing plate described outer air bag rubber diaphragm is pressed on the two ends of described sleeve, form outer air bag between described outer air bag rubber diaphragm and described sleeve, air intake opening on described sleeve is communicated with described outer air bag.

described interior air bag component comprises interior air bag gaseous core, interior air bag stationary installation and interior air bag rubber diaphragm, described interior air bag gaseous core one end is provided with air intake opening, described interior air bag gaseous core medium position is provided with the gas outlet, described interior air bag rubber diaphragm is hollow cylinder, the diameter of the film formed hollow cylinder of described interior air bag rubber is equal to or less than the diameter of hollow circular cylinder test specimen endoporus, described interior air bag stationary installation comprises set nut and sealing shroud cone, described interior air bag Rubber membrane cover is contained in the outer and described interior air bag rubber diaphragm of described interior air bag gaseous core two ends and is fixed on the two ends of described interior air bag gaseous core by described sealing shroud cone, described sealing shroud tapered sleeve is contained on described interior air bag gaseous core, described set nut is fastened on described sealing shroud cone on described interior air bag gaseous core, make and form interior air bag between described interior air bag rubber diaphragm and described interior air bag gaseous core, the diameter of described sealing shroud cone is less than the diameter of described hollow circular cylinder test specimen endoporus, make described interior air bag be placed in described hollow circular cylinder test specimen endoporus, the gas outlet of described interior air bag gaseous core is communicated with described interior air bag.

Described air bag pressing plate comprises end clamp plate and the outer end clamp plate of outer air bag in outer air bag, it is inboard that the interior end clamp plate of described outer air bag is pressed on described sleeve with described outer air bag rubber diaphragm, the outer end clamp plate of described outer air bag is pressed on described outer air bag rubber diaphragm outside described sleeve, and in described outer air bag, the outer end clamp plate of end clamp plate and outer air bag is fixed by described screw rod.

Described interior air bag rubber diaphragm and outer air bag rubber diaphragm are that two ends are thick, the structure of intermediate thin.

described air pressure control desk comprises two identical outlet lines being controlled by a total air valve, article two, outlet line is communicated with described outer air bag component and described interior air bag component respectively, described outlet line comprises the supercharge pump that connects successively from the total air valve to the gas outlet, gas cylinder, high-pressure valve, decompression valve, precision pressure gauge, pressure transducer, vent valve and delivery valve, described high-precision pressure gauge shows the actual air pressure that passes into described interior air bag component and outer air bag component, described pressure transducer records respectively the air pressure of described interior air bag component and outer air bag component, and convert pressure to electric signal and deliver to datalogger, described delivery valve and vent valve are to described interior air bag component and the pressurization of outer air bag component and release.

Be provided with outer air bag between described lower platen and described MTS Material Testing Machine supporting seat and support adjustment seat, described outer air bag supports adjustment seat and comprises supporting seat and adjustable plate, described supporting seat is fixed on described adjustable plate, described adjustable plate below is arranged on described MTS Material Testing Machine supporting seat, described supporting seat is connected with lower platen, described adjustable plate is provided with adjuster bar, described outer air bag component supports by described adjuster bar, and described adjustable plate is regulated the relative position of outer air bag component and hollow circular cylinder test specimen by described adjuster bar.

Owing to adopting said structure and method asphalt Triaxial tester to build the complicated applied force environment of test specimen, make asphalt strength study field expand to triaxial stress state from the single shaft stress.This test unit has following advantage:

(1) adjust the size of internal gas pressure, outer air pressure and xial feed, can form different triaxial stress states, the multi-axis stress state of asphalt under the good simulating wheel load action of energy, solved the problem that existing Triaxial tester is not suitable for asphalt, make asphalt strength study field expand to triaxial stress state from the one dimension stress, significant to the mechanical characteristic of asphalt under research complicated applied force state;

(2) owing to adopting combination of rigidity and flexibility formula load mode, make the asphalt Triaxial tester have advantages of and be easy to control, pressing plate, outer air bag and interior air bag mutually noninterfere preferably resolve the corner effect in traditional triaxial test;

(3) described air pressure control desk provides stable, accurate, adjustable air pressure for described outer air bag component and interior air bag component;

(4) test unit with low cost, simple, be convenient to promote.

In sum, the utility model---a kind of asphalt air bag Triaxial tester has simple, is convenient to promote, and can avoid the corner effect of test specimen corner, the advantage of bituminous concrete stress under the simulating wheel load action preferably.The air bag Triaxial tester makes asphalt strength study field expand to triaxial stress state from the single shaft stress, and is significant to mechanical characteristic, Asphalt Mixture Design and the bituminous pavement infringement control of asphalt under research complicated applied force state.

Description of drawings

Fig. 1 (a) is structural representation of the present utility model;

Fig. 1 (b) is the cut-open view of Fig. 1 (a) A-A face;

Fig. 2 is the structural representation of the utility model sleeve;

Fig. 3 (a) is the structural representation of the outer air bag of the utility model;

Fig. 3 (b) is the cut-open view of Fig. 3 (a) B-B face;

Fig. 3 (c) is the cut-open view of the outer air bag component of the utility model;

Fig. 4 is the structural representation of air bag in the utility model;

Fig. 5 is the utility model air pressure control desk system diagram;

Fig. 6 is the definition figure of typical asphalt triaxial test curve and breakdown point;

Embodiment

Below in conjunction with accompanying drawing, further describe the embodiment of this patent.

Embodiment:

1, make test specimen: adopt static pressure method or gyratory compaction legal system to make bitumen mixture specimen, it is 100mm that core boring sampling obtains external diameter, and internal diameter is 20mm, and height is 100mm hollow circular cylinder test specimen.Placed in the middle in order to guarantee bore position, designing and made external diameter is 101mm, and the annular location cap placed in the middle of internal diameter 21mm will be located cap sleeve placed in the middle on the test specimen surface before boring, if drill bit can smoothly by location cap placed in the middle, can guarantee accurately that bore position is placed in the middle.

2, determining of test specimen stress: the test specimen that asphalt air bag triaxial test adopts is hollow circular cylinder, and interior air bag and outer air bag apply air pressure P to test specimen inner chamber and outer wall respectively 1And P 0, the MTS Material Testing Machine applies xial feed P to test specimen.By Elasticity as can be known, inside radius is that r, external radius are that R, cross-sectional area are the hollow circular cylinder of A, is subjected to interior pressure P 1, external pressure P 0With the effect of xial feed P, at ρ place, distance test specimen center, suffered radial stress σ ρ, circumference stress With axial stress σ zBe respectively

Radial stress: σ ρ = - R 2 ρ 2 - 1 R 2 r 2 - 1 P 1 - 1 - r 2 ρ 2 1 - r 2 R 2 P 0

Circumference stress:

Axial stress:

The boundary condition of test specimen inwall is (σ ρ) ρ=r=-P 1, the boundary condition of outer wall is (σ ρ) ρ=R=-P 0, the axial stress σ that test specimen is suffered z, radial stress σ ρAnd circumference stress Be the three-dimensional principle stress; Change the size of internal gas pressure and outer air pressure, can be in the different stress field of the inner formation of test specimen.

3, assembling air bag component and test specimen: air bag component is the core component of this device, mainly comprises outer airbag components and interior airbag components.

As shown in Fig. 1 to 5, outer air bag component mainly is comprised of sleeve 1, outer air bag 5, air bag pressing plate 3, screw rod 4 etc.sleeve 1 is combined by upper bush 11 and lower sleeve 12, upper bush 11 and lower sleeve 12 two ends are fastened, seal by O-ring seal between the part that clamps, sleeve 1 leaves air intake opening 13 can pass into pressurized air, outer air bag 5 comprises outer air bag rubber diaphragm 51, outer air bag rubber diaphragm 51 is hollow cylindrical, described outer air bag rubber diaphragm two ends are thick, intermediate thin, the two ends, the outside of air bag rubber diaphragm 51 are provided with a circle groove 52 outside, outer air bag 5 is fixed on the outer rim at described sleeve 1 two ends by the two ends upset of outer air bag rubber diaphragm 51, groove 52 just is nested on the outer rim of sleeve 1, then the part that is fixed on sleeve 1 two ends outer rim of outer air bag rubber diaphragm 51 is fixing by air bag pressing plate 3, air bag pressing plate 3 comprises end clamp plate 31 and the outer end clamp plate 32 of outer air bag in outer air bag, the inboard of end clamp plate 31 fixing outer air bag rubber diaphragms 51 in outer air bag, the outside of the outer end clamp plate 32 fixing outer air bag rubber diaphragms 51 of outer air bag, in the outer air bag at sleeve two ends Shang Xia 1, end clamp plate is fixedly connected with by screw rod 4 with the outer end clamp plate of outer air bag, outer air bag rubber diaphragm 51 is fixed with sleeve 1, make the outside of outer air bag rubber diaphragm 51 and the inboard of sleeve 1 form the air bag that seals, outer air bag 5 is by the air intake opening 13 and outer air bag 5 internal communication on sleeve 1 surface.It is to consider that test specimen produces distortion appearance " waist drum " phenomenon in compression test that sleeve 1 is designed to the detachable structure in up and down, and the maximum gauge at outstanding position can reach 115~120mm, if make one-piece construction, can't take out the residual body of test specimen from sleeve.Make the detachable structure in up and down, can take out easily the residual body of test specimen.Outer air bag rubber diaphragm is made intermediate thin, the thick structure in two ends can prevent that process of the test China and foreign countries air bag 5 from extruding from the gap between air bag pressing plate 3 and test specimen 7.The air bag 5 thick 1.4mm in two ends of the present embodiment China and foreign countries, thick middle 1mm, groove is left at the two ends of outer air bag rubber diaphragm 51, can be embedded on sleeve 1, after outer air bag 5 and sleeve 1 assemble, compress outer air bag rubber diaphragm 51 and sleeve 1 with air bag pressing plate 3, tighten screw rod 4, make sleeve 1, outer air bag 5 and sleeve pressing plate 3 just form an integral body, test specimen 7 is placed on wherein, and outer air bag rubber diaphragm 51 can wrap up the outer cylinder surface of test specimen 7 fully.The diameter of outer air bag rubber diaphragm 51 and the internal diameter of pressing plate are slightly larger than the test specimen diameter, and test specimen can be put into easily and take out like this.

Interior air bag component 6 comprises interior air bag gaseous core 62, interior air bag stationary installation and interior air bag rubber diaphragm 61.interior air bag gaseous core 62 1 ends are provided with air intake opening, medium position is provided with the gas outlet, interior air bag stationary installation comprises sealing shroud cone 63, setscrew nut 64 and set nut 65, interior air bag rubber diaphragm 61 is hollow cylinder shaped, interior air bag rubber diaphragm 61 be sleeved on described interior air bag gaseous core 62 outer after, two ends by sealing shroud bore 63 and setscrew nut 64 be fixed on the two ends of interior air bag gaseous core 62, again by set nut 65 sealings, make the inboard and interior air bag gaseous core 62 of interior air bag rubber diaphragm 61 form the air bag of sealing, the two ends of interior air bag gaseous core 62 bore 63 by sealing shroud, setscrew nut 64 and set nut 65 sealings, in two set nuts 65, one has through hole and another is not with pore, when assembling set nut 65, must will be with leachy set nut correspondence to open leachy interior air bag gaseous core 62 1 ends, otherwise pressurized air can not pass into interior air bag component 6.The external diameter of interior air bag rubber diaphragm 61 is identical with the test specimen diameter of bore, is connected with the air pressure control desk by set nut and tracheae 65, and after pressurized air entered rubber diaphragm from draft tube, all air pressure all was added in the test specimen bore area.The characteristics of interior air bag component 6 are all surfaces that can cover the test specimen endoporus, and do not interfere with outer air bag 5 and top board 81 and lower platen 82.

After assembling interior air bag, depending on the difference of compression test and tension test, select corresponding load plate and connecting link to test.

When carrying out tension test, select shaggy pressing plate, with epoxy resin, test specimen 7 and top board 81 and lower platen 82 are adhesively fixed, uneven surface can play strengthens bonding effect.Along the circumferential direction leave screw on top board 81 and lower platen 82, be connected by the connector 94 on the stretching arm of screw and MTS, connector 94 on the stretching arm of MTS is ball pivot shape, test specimen automatic centering when the connector 94 of ball pivot shape can guarantee to apply pulling force by the internal locking nut, internal locking nut can realize that MTS and air bag component form an integral body.After assembling interior air bag component 6, by guarantee the accurate centering of test specimen with pedestal, be the support through accurately measuring with pedestal, can guarantee the accurate centering of test specimen after on connector 94 is placed in pedestal.If in the time of need applying outer air pressure, outer air bag is supported adjustment seat be arranged on lower platen 82 times, outer air bag supports adjustment seat and comprises supporting seat 93 and adjustable plate 91, supporting seat 93 is fixed on described adjustable plate 91, supporting seat 93 is connected with lower platen 82, adjustable plate 91 is provided with adjuster bar 92 and supports outer air bag component, regulates the relative position of outer air bag component and test specimen 7 by adjuster bar 92.

When carrying out compression test, select ganoid top board 81, ball pivot shape pressure head on the telescopic arm of MTS directly is placed on top board 81, depression bar one end is connected with the MTS arm of force, one end acts directly on ball pivot shape pressure head to the test specimen load application, and the pressure head of ball strand shape can guarantee that pressure is applied to the test specimen surface uniformly.Other mounting meanss are consistent with tension test.

the air pressure control desk comprises two identical outlet lines being controlled by a total air valve, article two, outlet line is communicated with described outer air bag component and described interior air bag component respectively, described outlet line comprises the supercharge pump 22 that connects successively to the gas outlet from total air valve 21, gas cylinder 23, high-pressure valve 24, decompression valve 25, precision pressure gauge 26, pressure transducer 27, vent valve 28 and delivery valve 29, air pressure control desk specific works flow process is: after opening total air valve 21, low-pressure compressed air enters supercharge pump 22, second-compressed in supercharge pump 22, ideal theoretical compression ratio is 10:1, actual compression ratio is 7:1, be that the 1MPa source of the gas can reach 7MPa after supercharge pump.The compression of supercharge pump 22 is discontinuous operations, and the air pressure of supercharge pump 22 outlets is unstable, enters gas cylinder 23 through the large high attenuation of pulsation of air pressure after cushioning, then by just obtaining reliable and stable test source of the gas after decompression valve 25.Be provided with high-precision pressure gauge 26, pressure transducer 27, vent valve 28 and delivery valve 29 after decompression valve 25.High-precision pressure gauge 26 shows the actual air pressure that passes into interior air bag component and outer air bag component, the air pressure of air bag component and outer air bag component in pressure transducer 27 records respectively, and convert pressure to electric signal and deliver to datalogger, delivery valve 29 and vent valve 28 are used for air bag component pressurization and release.Have two supercharge pumps that low-pressure gas source is pressurized to 7MPa in the regulation and control platform, interior air bag and outer air bag have oneself independently supercharge pump and gas cylinder, do not interfere with each other at high pressure gas bottleneck pressure separately.

4, insulation: assemble test specimen, interior air bag component, outer air bag component, upper lower platen, outer air bag and support adjustment seat and hollow cylinder bitumen mixture specimen and put into temperature control box and be incubated, temperature retention time needs more than 6 hours;

5, air pressure consing: open source of the gas the air pressure control desk is inflated, close source of the gas after inflation is completed, regulating interior air bag air pressure is 0.25MPa, and outer air bag air pressure is 0MPa, opens the internal air bag of transfer valve and outer air bag input compressed-air.

6, open data acquisition system (DAS) and the MTS Material Testing Machine of air pressure control desk, apply vertical compression load with 2mm/min speed, test period is 5 minutes, data acquisition density is made as 10 points/s, makes the test specimen inwall draw at first-press under the acting in conjunction of internal gas pressure and axial compression load-press to make up and destroy.After off-test, close high-pressure valve, open and unload air valve and drain air bag and endotracheal pressurized air, preserve test figure, again data are inputted origin software, set horizontal stroke, ordinate can obtain typical asphalt triaxial test curve as shown in Figure 6, the reach the standard grade intersection point of elastic stage tangent line and peak stress tangent line of overstress-strain curve draws vertical line to the axial strain coordinate axis, and the intersection point of vertical line and stress-strain curve is defined as breakdown point.Calculate σ according to formula 1 again ρ, σ z, with σ ρ, σ zBy the numerical values recited sequence, three principle stresses when being asphalt destruction repeat above-mentioned steps, obtain the parallel experiment result.

As can be known from the above table, the asphalt triaxial test can form the stress field that three-dimensional does not wait in test specimen inside, and the asphalt threeaxis test results is reliable, stable, discreteness is little.Drawing-pressing-pressing under the combined stress state, the compressive strength of bituminous concrete is lower than its uniaxial compressive strength, if carry out obviously danger partially of Pavement Structure Design with uniaxial compressive strength; If pressing-pressing-pressing under the combined stress state, the compressive strength of bituminous concrete is higher than its uniaxial compressive strength, if it is obviously too conservative to carry out the road surface consequence devised with uniaxial compressive strength.If the three dimension stress intensity with actual measurement is carried out Pavement Structure Design, obviously can play the potential strength of performance material, the effect of saving road-making material.Therefore, in Pavement Structure Design, need to measure with the triaxial test of rock device multi-shaft strength of asphalt, then carry out Pavement Structure Design according to this test findings.

Decapacitation draws-presses-presses outside test, change the size of internal gas pressure and outer air pressure, the asphalt Triaxial tester can also carry out triaxial extension test, draws-press composite test, pressure-pressure composite test, La-La-pressure composite test and pressure-pressure-pressure composite test, and these tests are the various stresses of bituminous concrete under the simulating wheel load action well.

Claims (6)

1. asphalt Triaxial tester, comprise the gentle pressure-controlled platform of MTS Material Testing Machine, also comprise outer air bag component, interior air bag component, top board and lower platen, it is characterized in that, described outer air bag component and interior air bag component provide adjustable air pressure by described air pressure control desk, the outer air bag of described outer air bag component is arranged on the outside of hollow circular cylinder test specimen and wraps up the outer cylinder surface of described hollow circular cylinder test specimen, the interior air bag of described interior air bag component be arranged in the endoporus of hollow circular cylinder test specimen and with described hollow circular cylinder test specimen endoporus close contact, described top board and lower platen are separately fixed at upper surface and the lower surface of described hollow circular cylinder test specimen, described lower platen is connected with described MTS Material Testing Machine supporting seat, described top board is connected with the telescopic arm of described MTS Material Testing Machine.
2. asphalt Triaxial tester according to claim 1, it is characterized in that, described outer air bag component comprises sleeve, the air bag pressing plate, outer air bag and screw rod, described sleeve surface is provided with the air intake opening that is communicated with the outside in described sleeve, described sleeve comprises upper bush and lower sleeve, described upper bush and lower sleeve sealed card are fitted together, described outer air bag rubber diaphragm is hollow cylinder, the diameter of the film formed hollow cylinder of described outer air bag rubber is equal to or greater than the diameter of hollow circular cylinder test specimen, the two ends that described outer air bag rubber diaphragm is placed on described sleeve inboard and described outer air bag rubber diaphragm are installed on described sleeve two ends and are fixed by described air bag pressing plate, fix by screw rod between the described air bag pressing plate of described sleeve upside and downside, make described air bag pressing plate described outer air bag rubber diaphragm is pressed on the two ends of described sleeve, form outer air bag between described outer air bag rubber diaphragm and described sleeve, air intake opening on described sleeve is communicated with described outer air bag.
described interior air bag component comprises interior air bag gaseous core, interior air bag stationary installation and interior air bag rubber diaphragm, described interior air bag gaseous core one end is provided with air intake opening, described interior air bag gaseous core medium position is provided with the gas outlet, described interior air bag rubber diaphragm is hollow cylinder, the diameter of the film formed hollow cylinder of described interior air bag rubber is equal to or less than the diameter of hollow circular cylinder test specimen endoporus, described interior air bag stationary installation comprises set nut and sealing shroud cone, described interior air bag Rubber membrane cover is contained in the outer and described interior air bag rubber diaphragm of described interior air bag gaseous core two ends and is fixed on the two ends of described interior air bag gaseous core by described sealing shroud cone, described sealing shroud tapered sleeve is contained on described interior air bag gaseous core, described set nut is fastened on described sealing shroud cone on described interior air bag gaseous core, make and form interior air bag between described interior air bag rubber diaphragm and described interior air bag gaseous core, the diameter of described sealing shroud cone is less than the diameter of described hollow circular cylinder test specimen endoporus, make described interior air bag be placed in described hollow circular cylinder test specimen endoporus, the gas outlet of described interior air bag gaseous core is communicated with described interior air bag.
3. asphalt Triaxial tester according to claim 2, it is characterized in that, described air bag pressing plate comprises end clamp plate and the outer end clamp plate of outer air bag in outer air bag, it is inboard that the interior end clamp plate of described outer air bag is pressed on described sleeve with described outer air bag rubber diaphragm, the outer end clamp plate of described outer air bag is pressed on described outer air bag rubber diaphragm outside described sleeve, and in described outer air bag, the outer end clamp plate of end clamp plate and outer air bag is fixed by described screw rod.
4. asphalt Triaxial tester according to claim 2, is characterized in that, described interior air bag rubber diaphragm and outer air bag rubber diaphragm are that two ends are thick, the structure of intermediate thin.
5. asphalt Triaxial tester according to claim 2, it is characterized in that, described air pressure control desk comprises two identical outlet lines being controlled by a total air valve, article two, outlet line is communicated with described outer air bag component and described interior air bag component respectively, described outlet line comprises the supercharge pump that connects successively from the total air valve to the gas outlet, gas cylinder, high-pressure valve, decompression valve, precision pressure gauge, pressure transducer, vent valve and delivery valve, described high-precision pressure gauge shows the actual air pressure that passes into described interior air bag component and outer air bag component, described pressure transducer records respectively the air pressure of described interior air bag component and outer air bag component, and convert pressure to electric signal and deliver to datalogger, described delivery valve and vent valve are to described interior air bag component and the pressurization of outer air bag component and release.
6. asphalt Triaxial tester according to claim 1 and 2, it is characterized in that, be provided with outer air bag between described lower platen and described MTS Material Testing Machine supporting seat and support adjustment seat, described outer air bag supports adjustment seat and comprises supporting seat and adjustable plate, described supporting seat is fixed on described adjustable plate, described adjustable plate below is arranged on described MTS Material Testing Machine supporting seat, described supporting seat is connected with lower platen, described adjustable plate is provided with adjuster bar, described outer air bag component supports by described adjuster bar, described adjustable plate is regulated the relative position of outer air bag component and hollow circular cylinder test specimen by described adjuster bar.
CN 201220739581 2012-12-28 2012-12-28 Bituminous mixture triaxial test device CN203025044U (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103076225A (en) * 2012-12-28 2013-05-01 长沙理工大学 Triaxial test device for asphalt mixture and test method
CN103792149A (en) * 2014-03-04 2014-05-14 大连理工大学 Bituminous pavement material side stability sensor based on fiber bragg gratings
CN104316409A (en) * 2014-11-03 2015-01-28 北京强度环境研究所 Form-fitting partial high-uniform-distribution external pressure following applying and loading device
CN105865930A (en) * 2016-04-11 2016-08-17 中南大学 Test device for realizing loading and unloading of different stress paths in rock holes
CN106092728A (en) * 2016-07-19 2016-11-09 河海大学 The control method of each point three-dimensional stress in asphalt circle ring column test specimen

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103076225A (en) * 2012-12-28 2013-05-01 长沙理工大学 Triaxial test device for asphalt mixture and test method
CN103792149A (en) * 2014-03-04 2014-05-14 大连理工大学 Bituminous pavement material side stability sensor based on fiber bragg gratings
CN104316409A (en) * 2014-11-03 2015-01-28 北京强度环境研究所 Form-fitting partial high-uniform-distribution external pressure following applying and loading device
CN104316409B (en) * 2014-11-03 2017-02-01 北京强度环境研究所 Form-fitting partial high-uniform-distribution external pressure following applying and loading device
CN105865930A (en) * 2016-04-11 2016-08-17 中南大学 Test device for realizing loading and unloading of different stress paths in rock holes
CN105865930B (en) * 2016-04-11 2018-06-29 中南大学 A kind of experimental rig realized in rock pore different stress paths and add off-load
CN106092728A (en) * 2016-07-19 2016-11-09 河海大学 The control method of each point three-dimensional stress in asphalt circle ring column test specimen

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