CN102854302A - Testing device and method for real-time measurement of cracking time and crack width of concrete at early age - Google Patents
Testing device and method for real-time measurement of cracking time and crack width of concrete at early age Download PDFInfo
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- CN102854302A CN102854302A CN2012103036720A CN201210303672A CN102854302A CN 102854302 A CN102854302 A CN 102854302A CN 2012103036720 A CN2012103036720 A CN 2012103036720A CN 201210303672 A CN201210303672 A CN 201210303672A CN 102854302 A CN102854302 A CN 102854302A
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Abstract
The invention discloses a testing device and a method for real-time measurement of cracking time and crack width of concrete at early age. The testing device comprises a concrete specimen square outside and round inside, an inner steel ring set in the inner round of the concrete specimen and a baseboard arranged at the at the lower end of the inner steel ring. 12 working strain gauges, in an upper layer, a middle layer and a lower layer, are pasted on four positions, with minimum thickness of the concrete specimen, on the inner steel ring; a temperature compensating sheet is vertically pasted near each working strain gauge; and the working strain gauges and the temperature compensating sheets are connected to a strain acquisition system by half bridge connection. Four positions in the middle of the outer surface with minimum thickness of the concrete specimen are respectively provided with a concrete surface crack meter; the surface crack meters are connected with a vibrating frequency recorder; and the vibrating frequency recorder and the strain acquisition system are connected to a computer. The device provided by the invention adopts two ways to observe cracking of concrete, raises the test accuracy, and is suitable for real-time measurement of cracking time and crack width of concrete at early age.
Description
Technical field
The present invention relates to proving installation and the assay method of a kind of real-time measurement concrete early-age cracking time and fracture width, belong to the concrete construction field.
Background technology
In the field of civil engineering, the proving installation of ring method researching condensed soil cracking resistance in length of time morning is a lot, but crack location is indefinite, can not the concrete cracking time of Real-time Measuring discharge observation and fracture width.
Summary of the invention
Technical matters to be solved by this invention is for above-mentioned the deficiencies in the prior art, and provides a kind of crack location clear and definite, and proving installation and the assay method that can observe cracking time and fracture width.
In order to solve the problems of the technologies described above, the present invention by the following technical solutions:
The proving installation of a kind of real-time measurement concrete early-age cracking time and fracture width, the concrete sample that comprises square-outside and round-inside, be arranged on the interior steel loop of concrete sample inner circle and the base plate that is arranged on interior steel loop lower end, it is characterized in that: at three layers of stickup of four position minute upper, middle and lowers at the minimum place of the corresponding concrete sample thickness of described interior steel loop totally 12 working strain gauges, and vertically near each working strain gauge paste a temperature compensation sheet, working strain gauge and temperature compensation sheet are connected to a strain acquisition system with the half-bridge connected mode, in the middle of the outside surface of four positions, the minimum place of concrete sample thickness, a concrete surface crack meter is set respectively, the surface crack meter is connected with a vibratory string frequency recorder, and described vibratory string frequency recorder and strain acquisition system all are connected to computing machine.
Paste foil gauge in interior steel loop position corresponding to the minimum place of concrete sample thickness, after the form removal, outside surface at the minimum place of concrete sample thickness is pasted the concrete surface crack meter, adopt two kinds of methods to observe simultaneously concrete early stage cracking, the concrete cracking time of Real-time Measuring discharge observation and fracture width.Exterior sheathing is comprised of dismountable four block plates, and the steel plate inner face posts polyfluortetraethylene plate, is convenient to the demoulding.
Paste working strain gauge in interior steel loop position corresponding to the minimum place of concrete sample thickness, can improve measuring accuracy, accurately judge concrete crack location, avoid concrete sample and interior steel loop friction force on the impact of cracking.
After the form removal, on the outside surface at the minimum place of concrete sample thickness, post the concrete surface crack meter, can accurately observe concrete cracking time and fracture width.
Described exterior sheathing is comprised of dismountable four block plates, and four block plate two ends all are drilled with threaded hole, is bolted whole exterior sheathing is fixed into an integral body, and the steel plate inner face sticks polyfluortetraethylene plate, is convenient to the demoulding.
Working strain gauge adopts the half-bridge connected mode to link to each other with strain acquisition system with the temperature compensation sheet, and strain acquisition system is connected with computing machine, in case the strain sudden change namely represents this place's concrete cracking.
Interior steel loop is made by the less indium steel of linear expansion coefficient, and during temperature variation, the distortion of interior steel loop almost can be ignored.
Proving installation and the assay method of a kind of real-time measurement concrete early-age cracking time and fracture width, step is as follows:
The first step: interior steel loop is placed on the stepped appearance steel base plate, and rear installation exterior sheathing screws the bolt of exterior sheathing, and tightly base plate ladder place is lived in interlock, to stop moving up and down of exterior sheathing.After the device assembling was finished, the exterior sheathing inner face sticked polyfluortetraethylene plate, is convenient to the demoulding.
Second step: punish three layers of stickup of upper, middle and lower totally 12 foil gauges in interior steel loop position corresponding to the minimum place of the cracking resistance device thickness of having assembled, temperature compensation sheet of vertical stickup is connected to working strain gauge and temperature compensation sheet on the quad near each working strain gauge.
The 3rd step: in the annulus of casting concrete between exterior sheathing and interior steel loop.After the form removal, paste 1 concrete surface crack meter in the outside surface centre position at the minimum place of concrete thickness, amount to 4, the concrete surface crack meter is connected on the quad.
The 4th step: working strain gauge and temperature compensation sheet are connected to strain acquisition system with the half-bridge connected mode, strain acquisition system is connected to computing machine.The surface crack meter is connected to the vibratory string frequency recorder, the vibratory string frequency recorder is connected to computing machine.Observe strain variation, Real-time Measuring discharge observation concrete cracking time and fracture width by computing machine.
Compared with prior art, the invention has the beneficial effects as follows: the concrete sample that adopts square-outside and round-inside, its crack location is clear and definite, be four positions at the minimum place of thickness, so inboard working strain gauge that pastes in these four positions, the time of knowing cracking that can be real-time, paste slit gauge in the outside, can measure the width in crack.
Description of drawings
Fig. 1 is the single unit system figure after the proving installation form removal of the present invention.
Fig. 2 is the vertical view of cracking resistance device before the form removal.
Fig. 3 is the vertical view of cracking resistance device after the form removal.
Fig. 4 is the exterior sheathing vertical view.
Wherein: 1, square-outside and round-inside cracking resistance device, 2, exterior sheathing, 3, interior steel loop, 4, stepped appearance steel base plate, 5, working strain gauge, 6, the temperature compensation sheet, 7, concrete surface crack meter, 8, strain acquisition system, 9, the vibratory string frequency recorder, 10, computing machine, 11, quad, 12, signal wire, 13, bolt, 14, handle, 15, concrete sample.
Embodiment
Below in conjunction with accompanying drawing, the present invention is elaborated:
As depicted in figs. 1 and 2, proving installation of the present invention is comprised of square-outside and round-inside cracking resistance device 1, working strain gauge 5, temperature compensation sheet 6, strain acquisition system 8, concrete surface crack meter 7, vibratory string frequency recorder 9, computing machine 10 etc., and square-outside and round-inside cracking resistance device 1 is comprised of exterior sheathing 2, interior steel loop 3, stepped appearance steel base plate 4, bolt 13, handle 14 etc.As shown in Figure 2, before the form removal, the interior steel loop of square-outside and round-inside cracking resistance device 1 is pasted 12 working strain gauges 5 altogether, is arranged on the upper, middle and lower quarterline of interior steel loop 3, a temperature compensation sheet 6 is set near each working strain gauge 5, and both adopt the half-bridge connection to carry out temperature compensation.As shown in Figure 3, after the form removal, paste 1 concrete surface crack meter in the outside surface centre position at the minimum place of concrete thickness, amount to 4.As shown in Figure 4, exterior sheathing 2 is comprised of dismountable four block plates, and four block plates connect into an integral body by bolt 13.Before the test, working strain gauge 5 and temperature compensation sheet 6 are connected to strain acquisition system 8, strain acquisition system 8 is connected to computing machine 10; Concrete surface crack 7 is connected to vibratory string frequency recorder 9, and vibratory string frequency recorder 9 is connected to computing machine 10.Observe strain variation, Real-time Measuring discharge observation concrete cracking time and fracture width by computing machine.
Claims (2)
1. proving installation of measuring in real time concrete early-age cracking time and fracture width, the concrete sample that comprises square-outside and round-inside, the base plate (4) that is arranged on the interior steel loop (2) of concrete sample inner circle and is arranged on interior steel loop (2) lower end, it is characterized in that: at three layers of stickup of four position minute upper, middle and lowers at the minimum place of the corresponding concrete sample thickness of described interior steel loop totally 12 working strain gauges (5), and near each working strain gauge (5) the vertical temperature compensation sheet (6) of pasting, working strain gauge (5) and temperature compensation sheet (6) are connected to a strain acquisition system (8) with the half-bridge connected mode, in the middle of the outside surface of four positions, the minimum place of concrete sample thickness, a concrete surface crack meter (7) is set respectively, surface crack meter (7) is connected with a vibratory string frequency recorder (9), and described vibratory string frequency recorder (9) and strain acquisition system (8) all are connected to computing machine (10).
2. assay method that adopts proving installation claimed in claim 1 to measure in real time concrete early-age cracking time and fracture width, it is characterized in that: concrete steps are as follows:
The first step: interior steel loop (3) is placed on the stepped appearance steel base plate (4), rear installation exterior sheathing (2), screw the bolt (13) of exterior sheathing (2), tightly base plate ladder place is lived in interlock, to stop moving up and down of exterior sheathing (2), after the device assembling was finished, exterior sheathing (2) inner face sticked polyfluortetraethylene plate, is convenient to the demoulding;
Second step: punish three layers of stickup of upper, middle and lower totally 12 working strain gauges (5) in interior steel loop (3) position corresponding to the minimum place of the cracking resistance device thickness of having assembled, the vertical temperature compensation sheet (6) of pasting is connected to working strain gauge (5) and temperature compensation sheet (6) on the quad (11) near each working strain gauge (5);
The 3rd step: in the annulus of casting concrete between exterior sheathing (2) and interior steel loop (3), after the form removal, outside surface at the minimum place of concrete thickness is pasted 1 concrete surface crack meter (7), amount to 4, concrete surface crack meter (7) is connected on the quad (11);
The 4th step: working strain gauge (5) and temperature compensation sheet (6) are connected to strain acquisition system (8) with the half-bridge connected mode, strain acquisition system (8) is connected to computing machine (10), surface crack meter (7) is connected to vibratory string frequency recorder (9), vibratory string frequency recorder (9) is connected to computing machine (10), observe strain variation, Real-time Measuring discharge observation concrete cracking time and fracture width by computing machine (10).
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103293064A (en) * | 2013-05-30 | 2013-09-11 | 江苏大学 | Concrete member for hui-shaped test |
| CN106248737A (en) * | 2016-07-19 | 2016-12-21 | 四川大学 | The testing method of short column is reinforced for FRP |
| CN108196038A (en) * | 2017-12-21 | 2018-06-22 | 中国水利水电科学研究院 | The test equipment and method of coagulation soil scene mechanics parameter under a kind of practical curing condition |
| CN109358181A (en) * | 2018-10-23 | 2019-02-19 | 济源市超光传感器系统工程有限公司 | A kind of highly sensitive sensing device for concrete crack detection |
| CN113074685A (en) * | 2021-02-01 | 2021-07-06 | 黄小六 | Road ground plane crack depth detection method |
| CN113916408A (en) * | 2021-08-23 | 2022-01-11 | 中建三局第三建设工程有限责任公司 | Method for measuring internal stress of concrete structure |
| CN114993816A (en) * | 2022-05-24 | 2022-09-02 | 三峡大学 | Method for measuring average crack width of concrete surface |
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| CN101929142A (en) * | 2009-06-26 | 2010-12-29 | 中国水利水电第一工程局有限公司 | Anti-seepage pressure reduction construction method of concrete dam body |
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| CN202770832U (en) * | 2012-08-24 | 2013-03-06 | 河海大学 | Testing device for conducting real-time measurement on cracking time and cracking width of concrete at early stage |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103293064A (en) * | 2013-05-30 | 2013-09-11 | 江苏大学 | Concrete member for hui-shaped test |
| CN106248737A (en) * | 2016-07-19 | 2016-12-21 | 四川大学 | The testing method of short column is reinforced for FRP |
| CN108196038A (en) * | 2017-12-21 | 2018-06-22 | 中国水利水电科学研究院 | The test equipment and method of coagulation soil scene mechanics parameter under a kind of practical curing condition |
| CN109358181A (en) * | 2018-10-23 | 2019-02-19 | 济源市超光传感器系统工程有限公司 | A kind of highly sensitive sensing device for concrete crack detection |
| CN113074685A (en) * | 2021-02-01 | 2021-07-06 | 黄小六 | Road ground plane crack depth detection method |
| CN113916408A (en) * | 2021-08-23 | 2022-01-11 | 中建三局第三建设工程有限责任公司 | Method for measuring internal stress of concrete structure |
| CN113916408B (en) * | 2021-08-23 | 2023-09-22 | 中建三局第三建设工程有限责任公司 | Method for measuring internal stress of concrete structure |
| CN114993816A (en) * | 2022-05-24 | 2022-09-02 | 三峡大学 | Method for measuring average crack width of concrete surface |
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Application publication date: 20130102 |