CN101738459B - Expansion/shrinkage stress testing device for cement-based material - Google Patents

Abstract

The invention relates to an expansion/shrinkage stress testing device for a cement-based material, which comprises an inner circular ring and an outer circular ring which are coaxial and have the same height, and a stress testing device and a data acquisition device which are electrically interconnected, wherein the inner circular ring and the outer circular ring are made of the same material; and the stress testing device comprises a plurality of test stress plates which are distributed evenly along the circumferential direction on the outer surface of the outer circular ring and the inner surface of the inner circular ring and are electrically connected with the data acquisition device. When the testing device is used, the cement-based material (such as pure slurry, mortar or concrete) is cast between the two rings. The expansion and shrinkage stress can be calculated according to the analysis of material mechanics by measuring the stress. Compared with the prior method, the testing device has the main advantages that: a, the testing device is simple, and simple and convenient to operate; b, the restraint stress is even; and c, the testing of starting self water addition molding can be implemented, the testing process needs no manpower to move the test piece, and continuous and automatic test can be realized.

Description

Expansion/shrinkage stress testing device for cement-based material

Technical field

The present invention relates to a kind of expansion/shrinkage stress testing device for cement-based material, can evaluate the swelling agent expansion effect for preparing expansive concrete, belong to cement-based material technical field of measurement and test.

Background technology

Expansive concrete refers to be mixed swelling agent or with expansive cement, under certain constraint condition, produces appropriateness and expand and produce certain concrete from stress in concrete.Be mainly used in reinforced concrete works and the mass concrete engineering of structure from the continuous placing of waterproof, fillibility expansion the second stage of the project, prolongation buildings expansion joint or post-cast strip spacing.The chemical reaction of expanded constituents dependence itself or react with other compositions of cement produces the contraction in certain confined expansion compensation or partial-compensation course of hardening in course of hardening.

The gordian technique of expansive concrete preparation is to mix swelling agent, produces and expands, and under certain constraint condition, produce turgor pressure stress, to compensate the tension producing due to contraction under drying condition, improves concrete splitting resistance.Evaluating in the effect of swelling agent compensate for shrinkage at present, cement paste, mortar, the concrete expansion/contraction deflection of swelling agent mixed in main or employing test under certain match ratio and curing condition, compare and pass judgment on the effect of different swelling agents, as JC 476 " cement expansive material " standard has specified to mix by test the restriction glue sand test specimen of a certain amount of swelling agent, by testing the airborne dry-shrinkage deformed of the limited expansion rate of maintenance 7d in 20 DEG C of water and relative humidity 65%, pass judgment on and the quality of more different swelling agents; Patent 00261525.8 " sand-cement slurry dilation measuring instrument " and patent 0324493.1 " concrete confined expansion constriction device " has proposed to be specifically designed to test water cement mortar and concrete limits the method for shrinking.These proving installations and evaluation method can reflect the size of different swelling agent expansion performances to a certain extent.But, due to a kind of elastic-plastic material with time varying characteristic of cement concrete.Its Young modulus and the parameter of creeping all can develop along with the time, and in length of time morning of hydration and hardening, modulus is relatively little, and the Relaxation Characteristics of creeping is obvious, and expansion performance is because stress relaxation consumes, and therefore large swell value not necessarily produces large turgor pressure stress; Otherwise after the hydration and hardening of cement reaches certain degree, modulus increases significantly, the lax behavior of creeping weakens, and swell value less under constraint condition also may produce large turgor pressure stress.Therefore, from the angle of assessment cracking risk, it is inadequate testing merely the expansion performance that expansion/contraction value evaluates swelling agent, and the evaluation method of science is to test out expansion/contraction stress more, correctly to reflect the expansion performance of swelling agent.

As a kind of elastic-plastic material, the stress itself producing due to distortion under constraint condition can not directly be measured, and the method conventionally adopting is the restrained deformation of measuring under constraint condition mostly, and further carrys out calculated stress by mechanical analysis.Constraint condition difference, the model difference of mechanical analysis, brings significant impact all likely to the precision of result of calculation.Axle constraint test method is to detect the cracking behaviors of test specimen under different condition by the stress of the axial deformation of confined concrete bar shaped test specimen and measurement test specimen.As the Cracking test frame of Munich, Germany polytechnical university development with the temperature stress testing machine developing afterwards, by the strain Real-Time Monitoring that concrete sample self-forming is started, and reset by stepper motor, thereby approximate 100% constraint is provided, and corresponding expansion/contraction stress also can be by being arranged on power sensor synchronism detection above stepper motor out.This method can reflect the stress-strain characteristics of concrete material comprehensively, all sidedly, also can be for the expansion performance of scientific evaluation swelling agent.But this method equipment one-time investment is very large, complicated operation, fails to apply in engineering practice.Patent 200310117098.0 has been announced a kind of easy sand-cement slurry, concrete shrinkage stress method of testing and device, wherein device as shown in Figure 1, wherein 1 for constraint reinforcing bar, 2 for slippage sleeve pipe, 3 for constraint end plate, 4 be anchoring piece, 5 for spheric probe, 6 for confining region, 7 be observation area, crack.Concreting, in framework of steel reinforcement, is out of shape together with framework of steel reinforcement, calculates expansion/contraction stress by the distortion of test two ends ailhead, and the computation process of stress σ is as follows:

$\mathrm{\&sigma;}=\mathrm{\&epsiv;}\&times;E\&times;\frac{{\mathrm{\&pi;<figure-callout\; id="2"\; label="D"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">D</figure-callout>}}^2}{4\&times;(A-\frac{{\mathrm{\&pi;<figure-callout\; id="2"\; label="D"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">D</figure-callout>}}^2}{4})}$

Wherein: E is the elastic modulus of reinforcing bar processed of limiting in " concrete confined expansion constriction device "; Springform measures 2.0 × 10 ⁵mPa;

D is the diameter of above-mentioned restriction reinforcing bar;

A is the cross-sectional area of " concrete confined expansion constriction device ";

ε is at the deflection of specifying measurement time test " concrete confined expansion constriction device ".

The deflection ε of above-mentioned concrete confined expansion constriction device is calculated by following formula:

$\mathrm{\&epsiv;}=\frac{L_2-L_1}{{\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="HSA00000005782800051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0}\&times;100\%$

Wherein: L ₂the length reading that-test block recorded in experimental period;

L ₁the initial reading of-test block length;

L ₀-test block datum length, is perfused with the length of sand-cement slurry or concrete part in " concrete confined expansion constriction device ".

Adopt and can calculate easily in this way the pucker & bloat stress of cement concrete under restrictive condition, but because constraint is mainly provided by middle reinforcing bar, its degree of restraint is mainly determined by the size of middle part reinforcing bar, degree of restraint is large not, and middle part and two ends all exist stress to concentrate.In addition, the method needs to move test specimen in test process, be difficult to resetting, therefore easily cause measuring error, affect result of calculation, and because needs are moved test specimen, cannot measure early stage expansion and differential contraction stress, and for the judgement of initial cracking time, because needs are artificially observed, therefore cannot accurately judge.

Summary of the invention

The invention provides a kind of expansion/shrinkage stress testing device for cement-based material, simple in structure, can realize the strain measurement starting from building moulding, operation is simple and reliable, and mechanical model is clear.

Described expansion/shrinkage stress testing device for cement-based material, comprise coaxial setting and highly identical inside and outside annulus, strain detection testing device and the data collector of electrical connection mutually, described inside and outside annulus material is identical, described strain detection testing device comprises multiple test foil gauges, described test foil gauge is uniformly distributed circumferentially on outer toroid outside surface and interior circle ring inner surface, and each test foil gauge is all electrically connected with data collector.

Use time of the present invention, cement-based material (as clean slurry, mortar or concrete) is cast between two rings.In expansion process, interior ring and outer shroud all provide constraint, by testing out the strain of interior ring and outer shroud, can accurately calculate differential expansion stress according to mechanical analysis.After expansion finishes, if cement-based material starts to shrink, early stage differential expansion stress discharges gradually, and in contraction process, interior ring can further provide again pinch confinement, by measuring the strain of interior ring, can calculate differential contraction stress according to the analysis meter of the mechanics of materials equally, further combined with the subtest such as tensile strength, elastic modulus means, can assess cracking risk.Make and use the present invention to test specifically and comprise the following steps:

1. thickness (thickness of the institute's moulding cement-based material) t between height h and two rings of definite annulus.The xsect of generally building moulding is square, now h=t.For cement paste or mortar, h is 25～40mm, for corresponding with free shrink test specimen, and the sectional dimension that should get 25 × 25mm or 40 × 40mm, i.e. h=t=25mm or 40mm; For concrete sample, h and t all should get 3 times of above values of the maximum particle diameter of gathering materials in concrete.

2. determine the size of inside and outside annulus, definite according to following following principle:

A) the external radius R of annulus in ₂for 50mm-200mm;

B) the inside radius R of outer toroid ₃for R ₂+ t, wherein t is the thickness of institute's moulding cement-based material;

C) annulus inside radius R in ₁according to required constraint degree, obtained by the computing formula of constraint degree

$\mathrm{\&psi;}=1-\frac{E_C^{\&prime;}}{E_S}\&CenterDot;\frac{1}{\frac{E_C^{\&prime;}}{E_S}-\frac{1-{\left(\frac{R_1}{R_2}\right)}^2}{1-{\left(\frac{R_3}{R_2}\right)}^2}\&CenterDot;\frac{[(1+v_C){\left(\frac{R_3}{R_2}\right)}^2+(1-v_C)]}{[(1+v_S){\left(\frac{R_1}{R_2}\right)}^2+(1-v_S)]}}---\left(I\right)$

Wherein E _sthe elastic modulus of annulus;

E _c' elastic modulus of tested cement-based material, calculate for simplifying, get empirical value;

V _sthe Poisson ratio of annulus;

V _cthe Poisson ratio of tested cement-based material;

Bring formula I into and can obtain R determining parameter ₁,

D) outer toroid wall thickness (R ₄-R ₃) equal (R ₂-R ₁)～1.2 × (R ₂-R ₁).

3. make annulus with line cutting mode, also can buy the steel pipe processing of commercially available suitable dimension.As preferred version of the present invention, the material of described inside and outside annulus is steel, more preferably mild carbon steel or Invar steel.Because the linear expansion coefficient of Invar steel is only 1/10 left and right of common iron, adopt Invar Steel material can more effectively avoid the impact of temperature.

4. on the flat board not absorbing water, install dog screw, planar surface is put the PVC plastic sheeting of one deck flexibility, and interior annulus and outer toroid are placed on to flat board above, and dog screw can guarantee that the center of circle of interior annulus and outer toroid overlaps.

5. the inside surface of ring outer surface and interior ring is along circumferentially evenly sticking multiple test foil gauges outside, and described test foil gauge can, by having bought on market, common are resistance strain gage.As preferred version, outer toroid outside surface and interior circle ring inner surface are along upwards respectively pasting 3-4 test foil gauge the week of centre-height.As improvement, described strain detection testing device also comprises temperature compensation foil gauge and reference member, and described temperature compensation foil gauge is attached to reference member surface, and described reference member is identical with outer toroid material with interior annulus.To test foil gauge and temperature compensation foil gauge is all electrically connected with data collector.

6. testing starting material and test unit deposits at least 1 day under should be under test temperature condition.

7. the clean slurry, mortar or the concrete mix that are stirred are divided to two-layer pouring between two steel loops, plug and pound closely knit.According to test needs, determine that needed curing condition carries out maintenance, every composing type test specimen is no less than 3.

8. build moulding complete after, can adopt immediately data collector to test, described data collector can be by having bought on market, as strainometer.Data collecting instrument should have at least 0.000001m/m resolution, and data acquisition interval should be set within 30 minutes.The strain of measuring inside and outside steel loop by strainometer, can calculate differential expansion stress or differential contraction stress in cement paste, mortar or concrete, and concrete grammar is as follows:

Cement paste, mortar or concrete inside radius are differential expansion stress or the differential contraction stress σ at r place _ccalculated by following formula,

${\mathrm{\&sigma;}}_C=\frac{\frac{{R_3}^2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}+1}{\frac{{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}^2}{{R_3}^2}-1}{P}_1-\frac{\frac{{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}^2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}+1}{1-\frac{{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}^2}{{R_3}^2}}{P}_2---\left(\mathrm{II}\right)$

P in formula (II) ₁and P ₂respectively the stress acting on outer shroud and interior ring,

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HSA00000005782800051.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=-\mathrm{\&epsiv;I}*\mathrm{Es}\frac{{R_2}^2-{R_1}^2}{{{2R}_2}^2}$

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HSA00000005782800022.png,HSA00000005782800051.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=-\mathrm{\&epsiv;o}*\mathrm{Es}\frac{{R_4}^2-{R_3}^2}{{{2R}_3}^2}$

ε _ifor surveying interior annulus strain;

ε _ofor the strain of actual measurement outer toroid;

The implication of other symbols of formula (II) is the same, works as r=R ₂shi Yingli is σ to the maximum _mAX.

9. synchronous forming test specimen carries out split tensile strength measurement, and evaluation or prediction cracking risk, specifically comprises following content:

A) initial cracking time T _cdetermine: determine the initial cracking time of each test specimen by interior ring strain sudden change, precision is not less than 0.25 day.If within the test duration cracking not, be recorded as ' not cracking ', and test the length of time while recording off-test simultaneously.

B) stress development speed: (there is no the test specimen of cracking) in the time of when cracking or off-test, the speed that stress develops average every day.

C) stress coefficient: the maximal value σ of test specimen differential contraction stress when test specimen shrinks _mAXratio with split tensile strength.

D) prediction of cracking risk can be carried out according to following table, and cracking risk reaches specialized range according to any one index in table 1 and judges.

The prediction of table 1 cracking risk

Adopt the present invention not only can retrain by test the strain on the inside and outside surface of steel loop, quantitatively calculate differential expansion stress and the differential contraction stress of mixing different swelling agent concrete/mortars, clean slurry, and carry out synthetic determination, prediction-constraint Water Under mud slurry, mortar or concrete cracking risk only by judgement initial cracking time, stress development speed and safety coefficient, compare with existing method, major advantage of the present invention is as follows:

A. test unit is simple, has multifunctionality, easy and simple to handle, and within the specific limits, sample dimensions, border condition on experimental result impact not quite, are easy to promote and standardization, are convenient to the analysis and comparison to test findings;

B. due to the axial symmetry of annulus, test specimen, in hoop Uniform Tension stress state, can not produce stress and concentrate, how much and clear boundary condition, and restraint stress is even, can effectively overcome axial test specimen and apply the difficulty of end restraint and easily produce the shortcomings such as eccentric;

C. retrain steel loop and can provide enough constrained to concrete shrinkage, constraint degree can be greater than 90%;

D. calculate the actual unrelieved stress (being contraction or expansion stress) of concrete ring with the steel loop strain recording, calculate theoretical elastic stress with free shrink, Deformed ring and concrete bullet mould, relatively unrelieved stress and theoretical elastic stress, the information of stress relaxation in material is provided, can reflect material expansion, drying shrinkage, self-constriction, creep, the combined action aspect splitting resistance such as ultimate elongation and elastic property, fully characterized expansion and the Shrinkage behavior of this elastic-plastic material of cement paste/mortar/concrete;

E. can realize the test that self-watering moulding starts, test process without people for moving test specimen, can realize test continuously, robotization, both can Validity Test early the length of time effectively avoided the personal error in test process, can accurately judge again initial cracking time.

Brief description of the drawings

Fig. 1 is the stress test device of patent 200310117098.0;

Fig. 2 is structural representation of the present invention;

Fig. 3 be in Fig. 2 in the vertical view cutaway drawing of inside and outside annulus;

Fig. 4 is the annulus strain of benchmark test specimen test in embodiment 1;

Fig. 5 is the annulus strain of mixing the test of swelling agent test specimen in embodiment 1;

Fig. 6 is benchmark test specimen and the stress development curve of mixing swelling agent test specimen in embodiment 1;

Fig. 7 is the annulus strain of benchmark test specimen test in embodiment 2;

Fig. 8 is the annulus strain of mixing the test of swelling agent test specimen in embodiment 2;

Fig. 9 is benchmark test specimen and the stress development curve of mixing swelling agent test specimen in embodiment 2.

Embodiment

As shown in Figure 2,3, expansion/shrinkage stress testing device for cement-based material comprises strain detection testing device and the data collector 4 of coaxial setting and highly identical inside and outside annulus 1,2, electrical connection mutually, described strain detection testing device comprises multiple test foil gauges 3, temperature compensation foil gauge 5 and reference member 6, on outer toroid 2 outside surfaces and interior annulus 1 inside surface, be respectively circumferentially uniformly distributed 4 described test foil gauges 3 along centre-height, described temperature compensation foil gauge 5 is attached to reference member 6 surfaces, and described reference member 6 is identical with outer toroid 2 materials with interior annulus 1.Each test foil gauge 3 and temperature compensation foil gauge 5 are all electrically connected with data collector 4.Described test foil gauge 3 is resistance strain gage, and described data collector 4 is strainmeter.Test foil gauge 3 and temperature compensation foil gauge 5, data collector 4 are all purchased.When test, first the cement-based material mixing 7 is cast between inside and outside annulus 1,2, then tests.

Embodiment 1

1: test basic parameter

Annulus material selection mild carbon steel, elastic modulus is 206GPa, Poisson ratio 0.3.

Annulus is of a size of R ₁=52mm, R ₂=60mm, R ₃=85mm, R ₄=95mm, b=t=25mm.

Test proportioning (only slurry) is as following table:

Table 2 is tested match ratio (kg/m ³)

In table 2, KB is benchmark test specimen (elastic modulus 20GPa, Poisson ratio 0.2), and PZJ is the test specimen (elastic modulus 18GPa, Poisson ratio 0.2) of mixing swelling agent, and experimental enviroment condition is 20 DEG C, 60% relative humidity.

2: test findings and analysis

Fig. 4 is the strain of C50-KB group steel loop.Not being subject to external force for clean slurry KB outer shroud, is 0 substantially, and therefore interior ring pressurized is negative strain.In in the time of 4.2 days, encircle strain sudden change, characterized the initial cracking time of test specimen.

Fig. 5 is the steel loop strain of mixing the test specimen of swelling agent, and test specimen is at first 1.5 days in swelling state, and outer shroud is the swollen normal strain that presents outwards, and interior ring pressurized presents negative strain to inside contracting.Start afterwards to shrink, until within 5.5 days, return to just length, the strain of interior ring outer shroud becomes 0, and test specimen starts clean contraction afterwards, and outer shroud does not stress substantially without strain, and interior ring pressurized is negative strain.

Fig. 6 is the maximal value σ of test specimen stress after adopting formula (II) to calculate according to test result _mAXdevelopment figure.Normal stress is tension, and negative stress is compressive stress.The test specimen constringency's pull should dint of not mixing swelling agent is linear growth substantially, develops into 4MPa left and right cracking, and possess certain unrelieved stress at 4.6 days, and this causes because cracking does not discharge internal contraction stress completely.Mix the swelling agent PZJ compressive pre-stress rapid growth that expands at the beginning, rise to 3MPa within less than the time, differential expansion stress slowly discharges afterwards, in the time of about 5.5 days, become 0. after due to contraction, slowly produce constringency's pull should dint.In the time that finishing, test is about 1.2MPa, not cracking.

The evaluation of table 3 cracking risk

Can find out that according to above-mentioned test results and analysis mixing of swelling agent produced differential expansion stress, compensate contraction, postpone initial cracking time, greatly reduce the cracking risk of cement paste, improve the splitting resistance of cement paste.

Embodiment 2

1: test basic parameter

Annulus material selection Invar steel, elastic modulus is 160GPa, Poisson ratio 0.3.

Annulus is of a size of R ₁=100mm, R ₂=115mm, R ₃=145mm, R ₄=160mm, h=t=75mm.

Concrete test proportioning is as following table (aggregate size 5mm-10mm):

Table 4 embodiment 2 concrete mix (kg/m ³)

In table 4, KB is normal concrete test specimen (elastic modulus 30GPa, Poisson ratio 0.2), PZJ is the concrete sample (elastic modulus 28GPa, Poisson ratio 0.2) of mixing swelling agent, experimental enviroment condition is 20 DEG C, 35% relative humidity, the maintenance of surface coverage vinyl plastics film waterproof is placed under 35% relative humidity dry after 2.5 days.

Fig. 7 is the strain of concrete KB group steel loop.In in 2.5 days, the strain of ring outer shroud is 0 substantially, i.e. concrete not obviously distortion under waterproof curing condition.After 2.5 days, start to be dried, interior ring pressurized does not ftracture in the time that test finishes.

Fig. 8 is for mixing the concrete steel loop strain of swelling agent.For concrete PZJ under first 2.5 days waterproof conditions in swelling state.Dry beginning shrinks afterwards, until within 7.5 days, return to just long, the strain of interior ring outer shroud substantially become 0. after test specimen start clean contraction, outer shroud does not stress substantially without strain, interior ring pressurized is negative strain.

Fig. 9 is the maximal value σ of test specimen stress after adopting formula (II) to calculate according to test result _mAXdevelopment figure.KB group is substantially unstressed before 2.5 days, starts near linear development starting dry post shrinkage stress.Develop into 2MPa left and right the 14 days length of time in off-test, but do not ftracture.Concrete PZJ differential expansion stress period of expansion not in 2.5 days.Started dry rear differential expansion stress at 2.5 days and start to reduce, during by about 7.5 days, swollen differential expansion stress is reduced to 0, starts afterwards to transfer to differential contraction stress.Last 14 days development of age are to 1MPa left and right, not cracking, although all do not ftracture, test findings proves the concrete contraction of having mixed partial-compensation of swelling agent equally, has reduced the speed of development of differential contraction stress, has improved concrete anti-crack ability.

Claims (7)

1. a cement-based material differential expansion stress proving installation, it is characterized in that, comprise coaxial setting and highly identical inside and outside annulus, strain detection testing device and the data collector of electrical connection mutually, described inside and outside annulus material is identical, described strain detection testing device comprises multiple test foil gauges, described test foil gauge is uniformly distributed circumferentially on outer toroid outside surface and interior circle ring inner surface, and each test foil gauge is all electrically connected with data collector;

The method for determining size of above-mentioned inside and outside annulus is as follows:

A) the external radius R of annulus in ₂for 50mm-115mm;

B) the inside radius R of outer toroid ₃for R ₂+ t, wherein t is the thickness of institute's moulding cement-based material;

C) annulus inside radius R in ₁according to required constraint degree, obtained by the computing formula of constraint degree

Wherein E _sthe elastic modulus of annulus;

E _c' elastic modulus of tested cement-based material;

ν _sthe Poisson ratio of annulus;

ν _cthe Poisson ratio of tested cement-based material;

Bring formula I into and can obtain R determining parameter ₁,

D) outer toroid wall thickness (R ₄– R ₃) equal (R ₂-R ₁)～1.2 × (R ₂-R ₁);

When described cement-based material is cement paste or mortar, the height h of described interior annulus is 25～40mm, and when described cement-based material is concrete, the height h of described interior annulus is the more than 3 times of maximum particle diameter that gather materials in concrete.

2. cement-based material differential expansion stress proving installation as claimed in claim 1 or 2, is characterized in that h=t.

3. cement-based material differential expansion stress proving installation as claimed in claim 1 or 2, it is characterized in that, described strain detection testing device also comprises temperature compensation foil gauge and reference member, described temperature compensation foil gauge is attached to reference member surface, and be electrically connected with data collector, described reference member is identical with outer toroid material with interior annulus.

4. cement-based material differential expansion stress proving installation as claimed in claim 1 or 2, is characterized in that, the material of described inside and outside annulus is steel.

5. cement-based material differential expansion stress proving installation as claimed in claim 4, is characterized in that, the material of described inside and outside annulus is mild carbon steel or Invar steel.

6. cement-based material differential expansion stress proving installation as claimed in claim 1 or 2, is characterized in that, outer toroid outside surface and interior circle ring inner surface are along upwards respectively pasting 3-4 test foil gauge the week of centre-height.

7. cement-based material differential expansion stress proving installation as claimed in claim 1 or 2, is characterized in that, described data collector has at least 0.000001m/m resolution, and data acquisition interval is not more than 30min.

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