CN103267682B - The proving installation of material creep and method of testing under tension and environment coupled action - Google Patents

The proving installation of material creep and method of testing under tension and environment coupled action Download PDF

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CN103267682B
CN103267682B CN201310174708.4A CN201310174708A CN103267682B CN 103267682 B CN103267682 B CN 103267682B CN 201310174708 A CN201310174708 A CN 201310174708A CN 103267682 B CN103267682 B CN 103267682B
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test specimen
jaw
strain
proving installation
bearing plate
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CN201310174708.4A
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CN103267682A (en
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陈惠苏
邱克超
孙璐
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东南大学
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Abstract

The invention discloses the proving installation of material creep under a kind of tension and environment coupled action, comprise support, counterweight, heating jacket, the container filling saturated inorganic salt solution, strain (FBG) demodulator, power supply, temperature controller, strain transducer and test specimen, support comprises location-plate, top ball pivot, upper jaw, cramp bar, bearing plate, bedplate, lower jaw and bottom ball pivot, and cramp bar is connected by sliding bearing with bearing plate; Being embedded in the groove of upper jaw with in the groove of lower jaw of test specimen; Counterweight is positioned on bearing plate, and heating jacket covers on the outside of support, and container is between support and heating jacket, and strain transducer is pasted onto in the outside wall surface of test specimen, and temperature controller overlaps with annular-heating and is connected.This proving installation can improve the reliability of test process, guarantees the accuracy of result.Meanwhile, also disclose the method for testing of this proving installation, simple to operation, test specimen in long-term load application process can be kept unstressed loose, and stress distribution is even.

Description

The proving installation of material creep and method of testing under tension and environment coupled action
Technical field
The invention belongs to materials ' durability measuring technology category, specifically, relate to proving installation and the method for testing of material creep under a kind of tension and environment coupled action.
Background technology
Since half a century, the accident that cement-based material causes because permanance is not enough is on the increase, and especially the Important Project such as dam, road, bridge, harbour and high-rise do not reach accident that design period just destroys and happen occasionally and cause tremendous economic loss and casualties.The phenomenon of creeping of cement-based material causes structural-load-carrying capacity to decline, and causes structure premature failure to destroy, the one of the main reasons of the lost of life.Although the research of creeping of relevant cement-based material oneself have decades, mostly research work is to consider the rule of development of creeping under the effect of single environment destructive factor, and load of creeping is mostly compression stress.But, in engineering structure, cement-based material runs under being mostly in drawing stress and varying environment acting in conjunction, compression under single factors effect research of creeping is difficult to reflect objective reality truly, and the time deformation of cement-based material is the result of multifactor joint effect effect.In addition, cement-based material internal injury degradation also anything but each destructive factor independent role cause simply adding and being worth of damage, but factors influence each other, superpose alternately.Under usual multiple damage factors effect, the degradation of cement-based material causes the summation of damage under being greater than each impairment factor independent role, namely there is damage superposition rule and answers, cause engineering structure performance to reduce fast and the lost of life.
Therefore, according to environment, weather and load situation residing for concrete in engineering reality, the principal element affecting permanance is carried out reasonable combination, system carries out cement-based material permanance research under dual or multiple damage factors effect, reciprocation between quantization factor and factor, be great science and technology and the theoretical puzzle of current cement-based material subject, oneself causes international academic community extensively and pay much attention at present, and its achievement in research will produce significant impact to durability design of structure and life prediction thereof.
The time deformation problem of research cement-based material under stress and environmental factor effect, top priority is exactly to set up the test method system simultaneously can considering drawing stress and 2 or more destructive factor.Consider in Practical Project, cement-based material works and runs under loaded state.Therefore, under research load and other destructive factor acting in conjunction cement-based material have important theoretical significance and widely engineer applied is worth, the cement-based material volume deformation rule particularly under drawing stress effect is studied for durability design of structure and is constructed very crucial.When setting up the cement-based material volume deformation test method considering such environmental effects, have 3 key technical problems to solve: the first, design can apply plate test loading system that is accurate, constant load to test specimen; The second, the reliable temperature and humidity control system of design stability; 3rd, set up can carry out continuously the test specimen loaded, nondestructive test method fast and data acquisition system (DAS).
Comprehensive existing cement-based material time deformation documents and materials are not difficult to find, what existing charger mostly adopted is spring-loaded mode, not yet has effective method that stress in process of the test can be kept constant.Its main cause has two: 1. in process of the test, material constantly deforms, and directly affect the stress that spring can provide, reality generation be the relaxation of material; 2. by the impact of loading stress, be difficult to utilize the load mode such as gravity or lever.
Above-mentioned shortcoming limits the correlativity of laboratory study and virtual condition cement-based material time deformation rule.Therefore, under development is applicable to drawing stress effect, and can keep holding for a long time the experimental provision that in lotus process, stress is constant, in multifactor research of creeping, there is important using value, structure durability evaluation is also provided to the experimental apparatus of science, prospect is very wide.
Summary of the invention
Technical matters: technical matters to be solved by this invention is: the proving installation that material creep under a kind of tension and environment coupled action is provided, this proving installation can improve the reliability of test process, guarantees the accuracy of test result; Also provide a kind of method of testing of this proving installation, this method of testing is simple to operation simultaneously, test specimen in long-term load application process can be kept unstressed loose, and stress distribution is even.
Technical scheme: for solving the problems of the technologies described above, the technical solution used in the present invention is:
The proving installation of material creep under a kind of tension and environment coupled action, described proving installation comprises support, counterweight, heating jacket, the container filling saturated inorganic salt solution, strain (FBG) demodulator, power supply, temperature controller, strain transducer and test specimen, wherein
Support comprises location-plate, top ball pivot, upper jaw, support bar, bearing plate, bedplate, lower jaw and bottom ball pivot, and top ball pivot is fixed on location-plate, is provided with groove in upper jaw, and upper jaw is connected on the ball pivot of top; Support bar is fixedly connected between location-plate and bedplate, and bearing plate is between location-plate and bedplate, and support bar is through bearing plate, and support bar is connected by sliding bearing with bearing plate; Bottom ball pivot is fixed on bearing plate, is provided with groove in lower jaw, and lower jaw is connected on the ball pivot of bottom; Lower jaw is relative with upper jaw;
The top of test specimen is embedded in the groove of upper jaw, and the bottom of test specimen is embedded in the groove of lower jaw; Counterweight is positioned on bearing plate, heating jacket covers on the outside of support, container is between support and heating jacket, strain transducer is pasted onto in the outside wall surface of test specimen, strain transducer is connected with strain (FBG) demodulator by wire, power supply is connected with the power input of temperature controller, and the output terminal of temperature controller overlaps with annular-heating and is connected.
Further, the proving installation of material creep under described tension and environment coupled action, also comprise levelling shoe, levelling shoe is 3 to 6, and levelling shoe is connected to the bottom surface of bedplate, and levelling shoe is evenly distributed on the bottom surface of bedplate.
Further, described top ball pivot, bottom ball pivot and bearing plate are made by light-weight high-strength material.
Further, described support bar is three, is evenly arranged between location-plate and bedplate.
Further, described strain transducer is resistance strain plate, and strain (FBG) demodulator is resistance-strain (FBG) demodulator.
Further, described strain transducer is fiber-optic grating sensor, and strain (FBG) demodulator is fiber Bragg grating (FBG) demodulator.
Further, described strain transducer and the axis being parallel of test specimen.
The method of testing of the proving installation of material creep under above-mentioned tension and environment coupled action, this method of testing comprises the following steps:
The first step: make material test specimen: utilize stirring machine stirring material starting material, make material slurry; Then material slurry is cast in dumb-bell shape mould, after material slurry sclerosis, forms material test specimen;
Second step: connect strain detection testing device: remove mould, abrasive material surface of test piece, removes surface scum, forms ganoid test specimen;
3rd step: carry out wetting balance to test specimen, prepares the saturated inorganic salt solution corresponding with target control humidity, then test specimen is put into the environment that saturated inorganic salt solution is formed, carry out wetting balance, and record the weight change of test specimen, when the weight of test specimen no longer changes, enter the 4th step;
4th step: regulate the temperature of environment residing for test specimen: first, be fixed on by strain transducer in the outside wall surface of test specimen, strain transducer is connected with strain (FBG) demodulator; Test specimen is placed between upper jaw and lower jaw, then the container filling inorganic salt solution is placed between support and heating jacket; Subsequently, the target temperature of environment residing for setting test specimen, by temperature controller and heating jacket, regulates the temperature of environment residing for test specimen, makes environment temperature residing for test specimen equal target temperature;
5th step: carry out test of creeping: observe the temperature variation in heating jacket by temperature controller, when temperature reaches desired value and no longer changes, start the test of creeping carrying out material: be placed on by counterweight on bearing plate, bearing plate applies tension by bottom ball pivot and lower jaw to test specimen, according to the weight loading counterweight, regulate the Creep Stress that test specimen is applied; Meanwhile, open strain (FBG) demodulator, gather strain data, by the strain of test specimen over time, measure the strained situation of the material creep performance of test specimen under drawing stress and environmental factor coupling.
Beneficial effect: compared with prior art, the present invention has following beneficial effect:
(1) in long-term load application process, it is loose that test specimen is unstressed, and stress distribution is even.In traditional material creep experiment, adopt spring or hydraulic way to load, test specimen generation time deformation can cause the decline of Creep Stress, and test specimen is in relaxation test state.In proving installation of the present invention, first, adopt the gravity of counterweight to apply to creep load, second, by sliding bearing, bearing plate is freely moved on support bar, effectively reduce the restriction of frictional resistance to test piece deformation, effective transmission of proof stress; Three, adopt light-weight high-strength material to make bearing plate, bottom ball pivot and lower jaw, the weight of bearing plate can be ignored compared with tensile creep stress, guarantees that each test specimen test stress condition is identical.In a word, in proving installation of the present invention, in long-term load application process, it is loose that test specimen is unstressed, and stress distribution is even.
(2) test specimen is coaxially stressed, is conducive to the accuracy improving test.Traditional loading apparatus of creeping, the drawing stress suffered by test specimen usually departs from the axis of time.In the present invention, solve this problem by the following method: the first, the size of strict guarantee test specimen, in the parallel cutting process of test specimen, control roughly with vernier caliper measurement, then carrying out polishing with sand paper accurately controls; The second, make strain transducer consistent with the axis of test specimen; Three, bearing plate utilizes sliding bearing to be connected with support bar, thus restriction bearing plate can only slide up and down on support bar, thus the transversely deforming of restriction bearing plate, reduce the possibility of the eccentric load-bearing of test specimen; Four, adopt ball pivot can ensure to remain in same axis in test specimen tension process, there will not be eccentric tension.
(3) temperature and humidity controls conveniently, and reliability is high.Traditional time deformation test is all carried out in the standard room of creeping, and temperature and humidity changes greatly.Different material creep distortion is very large by the impact of environment temperature and relative humidity.The present invention adopts intelligent temperature controller and well heater to control the temperature of the microenvironment residing for test specimen, adopts saturated inorganic salt solution to control the relative humidity of test specimen test environment.It is high, convenient and reliable that the present invention controls to have control accuracy to temperature and humidity, the advantage that adaptability is good.
(4) stress level is adjustable, and precision is high.Traditional loading apparatus of creeping relies on hydraulic pressure or spring to load, and the precision of loading is lower.The present invention adopts counterweight to load, and only need to adopt different counterweights just can realize different Creep Stress and load, and the precision of Creep Stress has relation with adopting the precision of counterweight, adopts high-precision counterweight can realize high-precision stress loading.
(5) strain data acquisition precision is high.High-precision strain transducer and strain (FBG) demodulator is adopted to carry out the time deformation value that capturing material creeps in process, data autostore in the present invention.Compared with the clock gauge of the artificial reading of traditional dependence, strain data acquisition precision of the present invention is high, and reliability is high, and continuity is good, and saves time.
Accompanying drawing explanation
Fig. 1 is the structural representation of proving installation of the present invention.
Fig. 2 is in the embodiment of the present invention 1, and stress level is to the effect string diagram of material extending Creep Characteristics.
Fig. 3 is in the embodiment of the present invention 2, and temperature is to the effect string diagram of material extending Creep Characteristics.
Fig. 4 is in the embodiment of the present invention 3, and relative humidity is to the effect string diagram of material extending Creep Characteristics.
Have in figure: support 1, counterweight 2, heating jacket 3, container 4, strain (FBG) demodulator 5, power supply 6, temperature controller 7, levelling shoe 8, strain transducer 9, test specimen 10, location-plate 101, top ball pivot 102, upper jaw 103, support bar 104, sliding bearing 105, bearing plate 106, bedplate 107, lower jaw 108 and bottom ball pivot 109.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail.
As shown in Figure 1, the proving installation of material creep under a kind of tension of the present invention and environment coupled action, comprises support 1, counterweight 2, heating jacket 3, the container 4 filling saturated inorganic salt solution, strain (FBG) demodulator 5, power supply 6, temperature controller 7, strain transducer 9 and test specimen 10.Support 1 comprises location-plate 101, top ball pivot 102, upper jaw 103, support bar 104, bearing plate 106, bedplate 107, lower jaw 108 and bottom ball pivot 109.Top ball pivot 102 is fixed on location-plate 101.Be provided with groove in upper jaw 103, and upper jaw 103 is connected on top ball pivot 102.Upper jaw 103 can rotate around top ball pivot 102, is convenient to the installation of test specimen 10.Support bar 104 is fixedly connected between location-plate 101 and bedplate 107.Location-plate 101 is set on support bar 104 top, the steadiness of support bar 101 can be improved, avoid it to wave.Bearing plate 106 is between location-plate 101 and bedplate 107.Support bar 104 is through bearing plate 106, and support bar 104 is connected by sliding bearing 105 with bearing plate 106.Bearing plate 106 is moved along support bar 104 by sliding bearing 105.Bottom ball pivot 109 is fixed on bearing plate 106.Be provided with groove in lower jaw 108, and lower jaw 108 is connected on bottom ball pivot 109.Lower jaw 108 can rotate around bottom ball pivot 109, is convenient to the installation of test specimen 10.Lower jaw 108 is relative with upper jaw 103.Lower jaw 108 and upper jaw 103 are between location-plate 101 and bearing plate 106.The top of test specimen 10 is embedded in the groove of upper jaw 103, and the bottom of test specimen 10 is embedded in the groove of lower jaw 108.Counterweight 2 is positioned on bearing plate 106.Heating jacket 3 covers on the outside of support 1.Heating jacket 3 can heat whole support 1, and then regulates the temperature of environment residing for test specimen 10.Container 4 is between support 1 and heating jacket 3.Strain transducer 9 is pasted onto in the outside wall surface of test specimen 10.As preferably, the axis being parallel of described strain transducer 9 and test specimen 10.Like this test specimen 10 coaxial stressed time, strain transducer 9 gather data more accurate.Strain transducer 9 is connected with strain (FBG) demodulator 5 by wire.Power supply 6 is connected with the power input of temperature controller 7, and output terminal and the annular-heating of temperature controller 7 overlap 3 and be connected.When strain transducer 9 is resistance strain plate, strain (FBG) demodulator 5 is resistance-strain (FBG) demodulator.When strain transducer 9 is fiber-optic grating sensor, strain (FBG) demodulator 5 is fiber Bragg grating (FBG) demodulator.
Further, the proving installation of material creep under described tension and environment coupled action, also comprise levelling shoe 8, levelling shoe 8 is 3 to 6, and levelling shoe 8 is connected to the bottom surface of bedplate 107, and levelling shoe 8 is evenly distributed on the bottom surface of bedplate 107.Levelling shoe 8 is set, location-plate 101, bearing plate 106 and bedplate 107 can be allowed all to be in horizontality, make material creep performance test more accurate.
Further, described top ball pivot 102, bottom ball pivot 109 and bearing plate 106 are made by light-weight high-strength material.Such as, light-weight high-strength material can adopt plastics, aluminium alloy and fibre-reinforced high molecular material.Make bearing plate 106 by light-weight high-strength material, the weight of bearing plate 106 can be reduced.Adopt light-weight high-strength material, the compressive stress needed for test can be born, and the weight of bearing plate 106 own is very little compared with the compressive stress of applying, its impact on test specimen 10 tensile creep distortional stress can be ignored, make test more accurate.
Further, described support bar 104 is three, is evenly arranged between location-plate 101 and bedplate 107.The connection that three support bars 104 can realize between location-plate 101 and bedplate 107 is set, and it is high to connect fixing.Meanwhile, three support bars 104 are set, are conducive to bearing plate 106 and stablize slippage.
In above-mentioned proving installation, the groove of upper jaw 103 and the top of test specimen 10 match, the groove of lower jaw 108 and the bottom of test specimen 10 match, and upper jaw 103 is connected with location-plate 101 by top ball pivot 102, and lower jaw 108 is connected with bearing plate 106 by bottom ball pivot 109.Groove, top ball pivot 102 and bottom ball pivot 109 are set, are conducive to the carrying center determining test specimen 10, make the Impact direction of test specimen 10 identical with the axis of test specimen 10.
Above-mentioned proving installation comprises: loading section, heating part, humid control part and strain acquirement part.Loading section forms primarily of support 1 and counterweight 2, the location-plate 101 in support 1 and base 107, is used for fixing whole support 1, ensures the stable of whole loading section; Bearing plate 106 is used for bearing the weight loading counterweight 2; Bearing plate 106, bottom ball pivot 109 and lower jaw 108 are used for transmitting tension to test specimen 10, and upper jaw 103 and top ball pivot 102 are used for carrying test specimen 10.In order to reduce to rub in test specimen 10 deformation process the resistance brought, bearing plate 106 sliding bearing 105 is reliably connected with support bar 104.Heating part forms primarily of temperature controller 7, heating jacket 3 and power supply 6.The target temperature of heating has been controlled by temperature controller 7.The real time temperature collecting heating jacket 3 is responsible for by temperature sensor in temperature controller 7, and feeds back to temp control switch, and the temperature signal of temp control switch to temperature sensor feedback processes.Humid control part mainly contains saturated inorganic salt solution and packoff two parts composition.The relative humidity simulation actual humidity environment utilizing saturated inorganic salt solution to be formed.Heating jacket 3 plays sealing function to whole support 1.Strain acquirement part mainly contains strain transducer 9 and strain (FBG) demodulator 5.
The method of testing of the proving installation of material creep under above-mentioned tension and environment coupled action, comprises the following steps:
The first step: make material test specimen: utilize stirring machine stirring material starting material, make material slurry; Then material slurry is cast in dumb-bell shape mould, after material slurry sclerosis, forms material test specimen.Test specimen 10 is made up of cement-based material, organic material or inorganic material.
Second step: connect strain detection testing device: remove mould, abrasive material surface of test piece, removes surface scum, forms ganoid test specimen 10.
3rd step: wetting balance is carried out to test specimen, prepare the saturated inorganic salt solution corresponding with target control humidity, then test specimen 10 is put into the environment that saturated inorganic salt solution is formed, carry out wetting balance, and record the weight change of test specimen 10, when the weight of test specimen 10 no longer changes, enter the 4th step.
In the third step, different according to the inorganic salt solution adopted, can realize controlling the relative humidity of environment residing for test specimen 10.
4th step: regulate the temperature of environment residing for test specimen: first, be fixed on by strain transducer 9 in the outside wall surface of test specimen 10, strain transducer 9 is connected with strain (FBG) demodulator 5; Test specimen 10 is placed between upper jaw 103 and lower jaw 108, then the container 4 filling inorganic salt solution is placed between support 1 and heating jacket 3; Subsequently, the target temperature of environment residing for setting test specimen, by temperature controller 7 and heating jacket 3, regulates the temperature of environment residing for test specimen 10, makes environment temperature residing for test specimen 10 equal target temperature.
5th step: carry out test of creeping: observe the temperature variation in heating jacket 3 by temperature controller 7, when temperature reaches desired value and no longer changes, start the test of creeping carrying out material: be placed on by counterweight 2 on bearing plate 106, bearing plate 106 applies tension by bottom ball pivot 109 and lower jaw 108 pairs of test specimens 10, according to the weight loading counterweight 2, regulate the Creep Stress that test specimen 10 is applied; Meanwhile, open strain (FBG) demodulator 5, gather strain data, by the strain of test specimen 10 over time, measure the strained situation of the material creep performance of test specimen 10 under drawing stress and environmental factor coupling.
When utilizing proving installation of the present invention to carry out stress-Environmental coupling test, first by the saturated inorganic salt solution of specified configuration, and test specimen 10 is put into wherein, carry out wetting balance, record weight change, when test specimen 10 weight does not have significant change, at test specimen 10 surface mount strain transducer 9, and reserved external connection, secondly test specimen 10 is placed between upper jaw 103 and lower jaw 108, and carries out the seal operation of sealing loading frame entirety.Then open temp controller 7, is heated to target temperature to test specimen 10, and is incubated a period of time.Six the cement-based material test specimens getting same proportioning subsequently, as one group, are wherein got three and are carried out tension test, obtain average tensile strength.Then proving installation is utilized to apply axial tensile stress to remaining three test specimens.Prior measuring and calculating is good will apply counterweight weight corresponding to stress level (considering that bearing plate is to the effect of test specimen), test specimen 10 is placed in the groove of upper jaw 103 and lower jaw 108 lentamente, and keeps the axis of test specimen 10 consistent with force direction.After last loaded, open the data collection task that strain (FBG) demodulator 5 carries out tensile creep deformation values.
Embodiment 1:
Cement asphalt mortar match ratio (kg/m 3): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05.By said ratio, after adopting forced stirrer to mix thoroughly, being poured in the dumb-bell shape mould of certain size by newly mixing cement asphalt mortar, then test specimen being put into standard curing room (temperature T=20 ± 3 DEG C, RH >=95%) maintenance and then taking out the length of time to regulation.The test specimen good to maintenance by MTS810 experimental machine carries out pulling strengrth test with reference to GB/T228.1-2010 " metal material stretching test Part I: room temperature test method ".According to recording pulling strengrth, adopt proving installation of the present invention and method of testing, apply 0.03,0.15 and 0.30 stress level (drawing stress/ultimate tensile stress of applying) respectively to test specimen, the temperature that controls environment is 20 DEG C, relative humidity RH=60%.After loaded, open strain (FBG) demodulator 5, carry out the tensile creep deformation test of cement asphalt mortar.Record stress and cement asphalt mortar tensile creep and be out of shape over time that relation is as shown in Figure 2.
In Fig. 2, horizontal ordinate represents the length of time of test of creeping, and unit: sky, ordinate represents the tensile creep deformation values of material, unit: μ ε.The tensile creep distortion rule of development in time of material when lines in Fig. 2 represent that stress level is 0.03,0.15 and 0.30 respectively.As can be seen from Figure 2, the tensile creep absolute value of this material increases along with the increase of stress level.Meanwhile, because the present invention can to strain data Quick Acquisition, can strain value changed with the length of time in reaction material tensile creep process effectively details.
Embodiment 2
Cement asphalt mortar match ratio (kg/m 3): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05.By said ratio, after adopting forced stirrer to mix thoroughly, watering in the dumb-bell shape mould of certain size by newly mixing cement asphalt mortar, then test specimen being put into standard curing room (temperature T=20 ± 3 DEG C, RH >=95%) maintenance and then taking out the length of time to regulation.The test specimen good to maintenance by MTS810 experimental machine carries out pulling strengrth test with reference to GB/T228.1-2010 " metal material stretching test Part I: room temperature test method ".According to recording pulling strengrth, adopt proving installation of the present invention and method of testing, apply 0.030 stress level (drawing stress/ultimate tensile stress of applying) to test specimen, setting heating arrangement target temperature is 20 DEG C, 40 DEG C and 80 DEG C, arranges relative humidity RH=60%.After loaded, open strain (FBG) demodulator 5, carry out the tensile creep deformation test of cement asphalt mortar under condition of different temperatures.Record temperature and cement asphalt mortar tensile creep and be out of shape over time that relation is as shown in Figure 3.
In Fig. 3, horizontal ordinate represents the length of time of test of creeping, unit: sky; Ordinate represents the time deformation value of material, unit: μ ε.Lines in Fig. 3 represent respectively environment temperature 20 DEG C, 40 DEG C, 60 DEG C and 80 DEG C time material time deformation situation over time.As can be seen from Figure 3, increase fast when the tensile creep absolute value of material starts with the growth in the length of time, then tend towards stability gradually.And tensile creep deformation values increases along with the increase of environment temperature.
Embodiment 3
Cement asphalt mortar match ratio (kg/m 3): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05.By said ratio, after adopting forced stirrer to mix thoroughly, watering in the dumb-bell shape mould of certain size by newly mixing cement asphalt mortar, then test specimen being put into standard curing room (temperature 20 ± 3 DEG C, RH >=95%) maintenance and then taking out the length of time to regulation.The test specimen good to maintenance by MTS810 experimental machine carries out pulling strengrth test with reference to GB/T228.1-2010 " metal material stretching test Part I: room temperature test method ".According to the pulling strengrth recorded, adopt proving installation of the present invention and method of testing, 0.030 stress level (drawing stress/ultimate tensile stress of applying) is applied to test specimen, set temperature is 20 DEG C, preparation controls relative humidity and is respectively 33%, the supersaturation inorganic salt solution of 75%, 59% and 98%.After loaded, open strain (FBG) demodulator 5, carry out the tensile creep deformation test under different relative humidities.Record relative humidity and cement asphalt mortar tensile creep be out of shape between relation as shown in Figure 4.
In Fig. 4, horizontal ordinate represents the length of time that tensile creep is tested, unit: sky; Ordinate represents the tensile creep deformation values of material, unit: μ ε.When lines in Fig. 4 represent that relative humidity is 33%, 59%, 75% and 98% respectively, the time deformation situation over time of material.As can be seen from Figure 4, tensile creep distortion absolute value first the increasing fast with the length of time of material, then tends towards stability.And tensile creep deformation values increases along with the increase of envionmental humidity.

Claims (10)

1. the proving installation of material creep under a tension and environment coupled action, it is characterized in that, described proving installation comprises support (1), counterweight (2), heating jacket (3), the container (4) filling saturated inorganic salt solution, strain (FBG) demodulator (5), power supply (6), temperature controller (7), strain transducer (9) and test specimen (10), wherein
Support (1) comprises location-plate (101), top ball pivot (102), upper jaw (103), support bar (104), bearing plate (106), bedplate (107), lower jaw (108) and bottom ball pivot (109), top ball pivot (102) is fixed on location-plate (101), upper jaw is provided with groove in (103), and upper jaw (103) is connected on top ball pivot (102); Support bar (104) is fixedly connected between location-plate (101) and bedplate (107), bearing plate (106) is positioned between location-plate (101) and bedplate (107), support bar (104) is through bearing plate (106), and support bar (104) is connected by sliding bearing (105) with bearing plate (106); Bottom ball pivot (109) is fixed on bearing plate (106), and lower jaw is provided with groove in (108), and lower jaw (108) is connected on bottom ball pivot (109); Lower jaw (108) is relative with upper jaw (103);
The top of test specimen (10) is embedded in the groove of upper jaw (103), and the bottom of test specimen (10) is embedded in the groove of lower jaw (108); Counterweight (2) is positioned on bearing plate (106), heating jacket (3) covers on the outside of support (1), container (4) is positioned between support (1) and heating jacket (3), strain transducer (9) is pasted onto in the outside wall surface of test specimen (10), strain transducer (9) is connected with strain (FBG) demodulator (5) by wire, power supply (6) is connected with the power input of temperature controller (7), and the output terminal of temperature controller (7) is connected with annular-heating cover (3).
2. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, also comprise levelling shoe (8), levelling shoe (8) is 3 to 6, levelling shoe (8) is connected to the bottom surface of bedplate (107), and levelling shoe (8) is evenly distributed on the bottom surface of bedplate (107).
3. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, described top ball pivot (102), bottom ball pivot (109) and bearing plate (106) are made by light-weight high-strength material.
4. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, described support bar (104) is three, is evenly arranged between location-plate (101) and bedplate (107).
5. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, described strain transducer (9) is resistance strain plate, and strain (FBG) demodulator (5) is resistance-strain (FBG) demodulator.
6. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, described strain transducer (9) is fiber-optic grating sensor, and strain (FBG) demodulator (5) is fiber Bragg grating (FBG) demodulator.
7. according to the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, the axis being parallel of described strain transducer (9) and test specimen (10).
8. the method for testing of the proving installation of material creep under tension according to claim 1 and environment coupled action, it is characterized in that, this method of testing comprises the following steps:
The first step: make material test specimen: utilize stirring machine stirring material starting material, make material slurry; Then material slurry is cast in dumb-bell shape mould, after material slurry sclerosis, forms material test specimen;
Second step: connect strain detection testing device: remove mould, abrasive material surface of test piece, removes surface scum, forms ganoid test specimen (10);
3rd step: wetting balance is carried out to test specimen, prepare the saturated inorganic salt solution corresponding with target control humidity, then test specimen (10) is put into the environment that saturated inorganic salt solution is formed, carry out wetting balance, and record the weight change of test specimen (10), when the weight of test specimen (10) no longer changes, enter the 4th step;
4th step: regulate the temperature of environment residing for test specimen: first, be fixed in the outside wall surface of test specimen (10) by strain transducer (9), strain transducer (9) is connected with strain (FBG) demodulator (5); Test specimen (10) is placed between upper jaw (103) and lower jaw (108), then the container (4) filling inorganic salt solution is placed between support (1) and heating jacket (3); Subsequently, the target temperature of environment residing for setting test specimen, by temperature controller (7) and heating jacket (3), the temperature of the residing environment of test specimen (10) is regulated, make the residing environment temperature of test specimen (10) equal target temperature;
5th step: carry out test of creeping: observe the temperature variation in heating jacket (3) by temperature controller (7), when temperature reaches desired value and no longer changes, start the test of creeping carrying out material: be placed on by counterweight (2) on bearing plate (106), bearing plate (106) applies tension by bottom ball pivot (109) and lower jaw (108) to test specimen (10), according to the weight loading counterweight (2), regulate the Creep Stress that test specimen (10) is applied; Simultaneously, open strain (FBG) demodulator (5), gather strain data, by the strain of test specimen (10) over time, measure the strained situation of test specimen (10) the material creep performance under drawing stress and environmental factor coupling.
9. according to the method for testing of the proving installation of material creep under tension according to claim 8 and environment coupled action, it is characterized in that, in the described first step, test specimen (10) is made up of cement-based material.
10. according to the method for testing of the proving installation of material creep under tension according to claim 8 and environment coupled action, it is characterized in that, in the described first step, test specimen (10) is made up of organic material.
CN201310174708.4A 2013-05-13 2013-05-13 The proving installation of material creep and method of testing under tension and environment coupled action CN103267682B (en)

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