CN217466923U - Novel annular anti-crack test device of concrete restraint shrinkage - Google Patents
Novel annular anti-crack test device of concrete restraint shrinkage Download PDFInfo
- Publication number
- CN217466923U CN217466923U CN202220731620.2U CN202220731620U CN217466923U CN 217466923 U CN217466923 U CN 217466923U CN 202220731620 U CN202220731620 U CN 202220731620U CN 217466923 U CN217466923 U CN 217466923U
- Authority
- CN
- China
- Prior art keywords
- inner ring
- concrete
- annular
- knife
- ring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000012360 testing method Methods 0.000 title claims abstract description 39
- 238000005336 cracking Methods 0.000 claims abstract description 13
- 230000001939 inductive effect Effects 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 4
- 238000011156 evaluation Methods 0.000 abstract description 3
- 230000006698 induction Effects 0.000 description 11
- 238000000034 method Methods 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Landscapes
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The utility model provides a novel anti crack test device of concrete restraint shrink annular, including bottom plate, inner ring, outer loop, inner ring releasable connection is in the bottom middle part, outer loop releasable connection is on the bottom plate, and the inner ring is located the outer loop, encloses into the annular between bottom plate, inner ring and the outer loop and pours the district, and concreting has encircled in the district is pour to the annular, installs induced edge of a knife device on the bottom plate in district is pour to the annular, induced edge of a knife device includes at least one edge of a knife group, edge of a knife group includes a plurality of induced edges of a knife, and the induced edge of a knife includes square blade, and square blade upper edge is provided with the triangle-shaped knife tip. The utility model relates to a rationally, the position that accurate crack appears to eliminate the randomness that the crack appears, and then the anti-cracking performance of accurate evaluation early age concrete under the restriction shrinkage condition.
Description
Technical Field
The utility model relates to a novel anti crack test device of concrete restraint shrink annular.
Background
Early shrinkage is an inherent property of concrete, and cracks are easily generated due to low tensile strength of early concrete. The existence of cracks provides channels for the invasion of aggressive media, and the durability of concrete is seriously influenced. Aiming at the early shrinkage deformation measurement of concrete, the evaluation of the crack resistance of concrete has become a focus of urgent attention at present.
The mechanism of concrete shrinkage is complex, the influence factors are more, and the selection of the test research method of concrete shrinkage is directly related to the accuracy of the test result. The scholars at home and abroad mainly adopt the following steps in the aspect of researching the shrinkage cracking performance of concrete: a flat plate constraint experiment method, a uniaxial constraint experiment method and an annular constraint experiment. The advantages of the plate method constraint experiment are as follows: the cracking speed is high, the cracking sensitivity is high, and the evaluation system is complete; however, the plate method has certain disadvantages: external environmental factors are difficult to control, the constraint stress is uncontrollable, sufficient precision is lacked, and the difference with actual engineering is large. The uniaxial constraint method has the characteristics of high accuracy and small test error, and can also analyze early concrete performance parameters such as the elastic modulus, the thermal expansion coefficient, the creep and the like of the concrete; however, the single-shaft constraint test device has high manufacturing cost and troublesome manufacturing process, and the system linearity is ensured not to be eccentric and has no additional friction force and torsion effect. Compared with the former two test methods, the circular ring constraint test device is simple, convenient to operate and easy to popularize and standardize. The ring constraint test method has the advantages that the principle is simple, axisymmetric constraint is provided, the detection and the record of the initial cracking time are more real, the constraint of the inner ring on the concrete is uniformly distributed, and the test can be analyzed and simulated by adopting numerical simulation; however, the circular confinement test can provide limited concrete confinement, random crack locations, long test times (even months without cracking), and poor sensitivity.
For the existing harvesterDue to the limitation of shrinkage constraint experiments, part of scholars propose an elliptical constraint test method to solve the problems that the degree of constraint of a circular ring is limited and cracks are random and difficult to test. The Zhou et al (Assessment of restrained damping vibration damping characteristics: experimental and numerical. ASCE J Mater Civ Engng 2014) study showed that relative to the traditional concrete toroid constraint, R is a complex of two or more of the above-mentioned two or more of the above-mentioned two or the above-mentioned two parts 1 /R 2 The elliptical concrete ring of the number of the steel sheets is 2-3, so that stronger constraint stress can be provided, and cracks can be accelerated to appear. Dong W et al (A simplified method for prediction of cracking and particulate matter cracking under strained cracking J]Engineering frame Mechanics, 2014, 131: 687- 1 /R 2 The maximum tensile stress in the circumferential direction of the elliptical ring of =2 is 3.6 times that of the circular ring, and the constraint rigidity can be significantly improved. Meanwhile, the crack occurs at a position close to the apex on the major axis of the oval concrete ring. Therefore, the elliptical constraint test method can remarkably improve the constraint rigidity and concentrate the position range of the crack occurrence more.
Disclosure of Invention
In view of this, the invention aims to provide a novel concrete shrinkage-constrained annular anti-cracking test device, which can accurately determine the position of cracks to eliminate the randomness of cracks, and further accurately evaluate the anti-cracking performance of early-age concrete under the shrinkage-constrained condition.
The invention is realized by adopting the following scheme: the utility model provides a novel anti crack test device of concrete restraint shrink annular, includes bottom plate, inner ring, outer loop, inner ring releasable connection is in the bottom middle part, outer loop releasable connection is on the bottom plate, and the inner ring is located the outer loop, encloses into the annular between bottom plate, inner ring and the outer loop and pours the district, and the annular is pour and is encircled concrete in the district, installs induced edge of a knife device on the bottom plate in the annular area of pouring.
Further, the outer wall of the inner ring is elliptical, and the size of the inner ring satisfies the following relational expression:
inner ring long axis R 1 : inner ring minor axis R 2 : inner ring thicknessDegree T 1 : inner ring height H 1 =12：6：1：6。
Further, the concrete ring is an oval ring body, and the size of the concrete ring meets the following relational expression:
inner ring height H 1 : height H of concrete ring 2 : concrete ring thickness T 2 =2：2：1。
Furthermore, the inner wall of the outer ring is an oval body corresponding to the outer wall of the concrete ring.
Further, the induction knife edge device comprises at least one knife edge group, the knife edge group comprises a plurality of induction knife edges, each induction knife edge comprises a square knife body, and a triangular knife tip is arranged on the upper edge of each square knife body.
Furthermore, the triangular tool tip is an isosceles triangle.
Furthermore, the annular pouring area is arranged in the inner ring long shaft R 1 The extended line of the knife edge group is symmetrically provided with knife edge groups, and the induced knife edge of each knife edge group is along the long axis R of the inner ring 1 The extended lines are welded on the bottom plate at intervals, and the blade body of the induced blade is vertical to the long axis R of the inner ring 1 An extension line of (a).
Furthermore, strain gauges connected with an external detection device are mounted on the inner walls of the two sides of the inner ring in the long axis direction.
Compared with the prior art, the utility model discloses there is following beneficial effect: the design is reasonable, the position of the crack is accurate, the randomness of the crack is eliminated, and the crack resistance of the early-age concrete under the condition of limited shrinkage is accurately evaluated.
Drawings
Fig. 1 is a schematic top view of an embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;
fig. 3 is a schematic view of an induced knife edge structure according to an embodiment of the present invention.
In the figure: 1-a bottom plate; 2-inner ring; 3-a strain gauge; 4-annular pouring area; 5-inducing a knife edge; 6-square blade; 7-triangular tool tip; 8-concrete ring.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
In long-term research on annular constrained shrinkage test, the inventor finds that R 1 /R 2 =2 elliptical constrained shrinkage can significantly increase the constraint stiffness and can predict the range of locations where cracks occur. According to the fracture mechanics theory, the existence of the initial defect in the concrete can cause local stress concentration, and the risk of cracking of the test piece can be greatly improved. Based on the constraint annular test recommended by ASTMC1581/C1581M-09a, R is provided 1 /R 2 =2 elliptical ring restraint and set the idea of knife edge induction at the apex of the major axis to induce the appearance of annular specimen cracks.
As shown in fig. 1-3, the present embodiment provides a novel anti-crack test device of concrete constrained shrinkage ring shape, including bottom plate 1, inner ring 2, outer loop (not shown), inner ring detachable connection is in the middle part of the bottom, outer loop detachable connection is on the bottom plate, and the inner ring is located the outer loop, encloses into annular pouring district 4 between bottom plate, inner ring and the outer loop, and the annular pouring is distinguished in pouring concrete ring 8, installs induced edge of a knife device on the bottom plate in annular pouring district.
In this embodiment, the outer wall of the inner ring is an ellipse, and the size of the inner ring satisfies the following relation:
inner ring long axis R 1 : inner ring minor axis R 2 : inner ring thickness T 1 : inner ring height H 1 =12：6：1：6。
In this embodiment, it is characterized in that the concrete ring is an elliptical ring body, and the size of the concrete ring satisfies the following relation:
inner ring height H 1 : height H of concrete ring 2 : concrete ring thickness T 2 =2：2：1。
In this embodiment, the inner wall of the outer ring is an elliptical body corresponding to the outer wall of the concrete ring.
In this embodiment, the knife edge inducing device includes at least one knife edge group, the knife edge group includes a plurality of inducing knife edges 5, the inducing knife edges include a square knife body 6, and a triangular knife tip 7 is disposed on the upper edge of the square knife body.
In this embodiment, the triangular tool tip is an isosceles triangle.
In this embodiment, the annular casting area is located within the inner ring long axis R 1 The extended line of the knife edge group is symmetrically provided with knife edge groups, and the induced knife edge of each knife edge group is along the long axis R of the inner ring 1 The extension lines of the induction knife edge are welded on the bottom plate at intervals, and the knife body of the induction knife edge is perpendicular to the extension line of the inner ring long axis R1.
In this embodiment, strain gauges 3 connected to an external detection device are attached to the inner walls of the inner ring on both sides in the longitudinal direction.
In this embodiment, the actual parameters of the apparatus are: long axis R of steel ring 1 =150mm, minor axis R 2 =75mm, the thickness of the steel ring is 12.5 mm, the thickness of the concrete ring is 37.5 mm, and the height is 75 mm. The induction knife edge is made of steel, the side length of the bottom of the induction knife edge is 10mm, and the section of the top of the induction knife edge is an isosceles right triangle with the bottom of 10mm and the height of 5 mm. The induction knife edge is flush with the bottom of the test piece and is welded with the test piece.
In the embodiment, when in use, firstly, a C40 concrete with a water-cement ratio of 0.34 is used for pouring the constraint annular test piece, and after the pouring is finished, the surface of the test piece is covered by a preservative film to avoid water loss. It was placed in a laboratory environment for 24 hours. And (3) removing the outer ring and the bottom plate, sticking the upper surface and the lower surface of the concrete test piece by using double-layer tin foil paper to enable the water in the concrete to be dissipated from inside to outside along the radial direction, then sticking the strain gauge on the long axis direction of the test piece, placing the treated test piece in a constant temperature and humidity environment (25 ℃, 50% RH) for curing, and recording the occurrence time of cracks through a stress-strain curve, thus terminating the test.
The traditional constraint device has limited constraint on concrete, random crack occurrence positions, long test time and poor sensitivity. Reasonable improvement is carried out on a constraint annular test device based on ASTM recommendation, and R is adopted 1 /R 2 The elliptical constraint test device with the constraint rigidity of =2 remarkably improves the constraint rigidity, accelerates the generation of cracks and shortens the test time. Meanwhile, due to the oval geometric effect, cracks are often generated near the top point of the long axis, and the knife edge induction is arranged at the bottom of the long axis, so that the generation position of the cracks can be accurately determined.
Any technical solution disclosed in the present invention is, unless otherwise stated, disclosed a numerical range if it is disclosed, and the disclosed numerical range is a preferred numerical range, and any person skilled in the art should understand that: the preferred ranges are merely those values which are obvious or representative of the technical effect which can be achieved. Because numerical value is more, can't be exhaustive, so the utility model discloses just disclose some numerical values with the illustration the technical scheme of the utility model to, the numerical value that the aforesaid was enumerated should not constitute right the utility model discloses create the restriction of protection scope.
If the terms "first," "second," etc. are used herein to define parts, those skilled in the art will recognize that: the terms "first" and "second" are used merely to distinguish one element from another in a descriptive sense and are not intended to have a special meaning unless otherwise stated.
The utility model discloses if disclose or related to mutual fixed connection's spare part or structure, then, except that other the note, fixed connection can understand: a detachable fixed connection (for example using bolts or screws) is also understood as: non-detachable fixed connections (e.g. riveting, welding), but of course, fixed connections to each other may also be replaced by one-piece structures (e.g. manufactured integrally using a casting process) (unless it is obviously impossible to use an integral forming process).
In addition, the orientation or positional relationship indicated in any of the above-mentioned technical solutions of the present disclosure for indicating positional relationship, such as "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of describing the present disclosure, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present disclosure, and the terms used to indicate shape in any of the above-mentioned technical solutions of the present disclosure are meant to include shapes similar, analogous or approximate thereto unless otherwise stated.
The utility model provides an arbitrary part both can be assembled by a plurality of solitary component parts and form, also can be the solitary part that the integrated into one piece technology was made.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same; although the present invention has been described in detail with reference to preferred embodiments, it should be understood by those skilled in the art that: the invention can be modified or equivalent substituted for some technical features; without departing from the spirit of the present invention, it should be understood that the scope of the claims is intended to cover all such modifications and variations.
Claims (8)
1. The utility model provides a novel anti test device that splits of concrete restraint shrink annular, a serial communication port, including bottom plate, inner ring, outer loop, inner ring releasable connection is in the bottom middle part, outer loop releasable connection is on the bottom plate, and the inner ring is located the outer loop, encloses into the annular between bottom plate, inner ring and the outer loop and pours the district, pours the concrete ring in the district in the annular, installs induced edge of a knife device on the bottom plate in district is pour to the annular.
2. The concrete constrained shrinkage annular novel crack resistance test device according to claim 1, wherein the outer wall of the inner ring is elliptical, and the size of the inner ring satisfies the following relational expression:
inner ring long axis R 1 : inner ring minor axis R 2 : inner ring thickness T 1 : inner ring height H 1 =12：6：1：6。
3. The concrete constrained shrinkage annular novel anti-cracking test device according to claim 2, wherein the concrete ring is an oval ring body, and the size of the concrete ring satisfies the following relational expression:
inner ring height H 1 : height H of concrete ring 2 : concrete ring thickness T 2 =2：2：1。
4. The concrete constrained shrinkage annular novel crack resistance test device according to claim 3, wherein the outer ring inner wall is an oval body corresponding to the concrete ring outer wall.
5. The concrete constrained shrinkage annular novel crack resistance testing device according to claim 1, wherein the inducing knife edge device comprises at least one knife edge group, the knife edge group comprises a plurality of inducing knife edges, each inducing knife edge comprises a square knife body, and a triangular knife tip is arranged on the edge of each square knife body.
6. The concrete constrained shrinkage annular novel crack resistance test device according to claim 5, wherein the triangular tool tip is an isosceles triangle.
7. The novel annular concrete constrained shrinkage crack resistance test device according to claim 6, wherein the annular pouring area is arranged in the inner annular long axis R 1 The extended line of the knife edge group is symmetrically provided with knife edge groups, and the induced knife edge of each knife edge group is along the long axis R of the inner ring 1 Are welded on the bottom plate at intervalsThe blade of the induced blade is vertical to the long axis R of the inner ring 1 An extension line of (a).
8. The novel annular concrete constrained shrinkage crack resistance testing device as claimed in claim 1, wherein strain gauges connected with an external detection device are mounted on the inner walls of the two sides of the inner ring in the long axis direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220731620.2U CN217466923U (en) | 2022-03-31 | 2022-03-31 | Novel annular anti-crack test device of concrete restraint shrinkage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220731620.2U CN217466923U (en) | 2022-03-31 | 2022-03-31 | Novel annular anti-crack test device of concrete restraint shrinkage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217466923U true CN217466923U (en) | 2022-09-20 |
Family
ID=83267935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220731620.2U Expired - Fee Related CN217466923U (en) | 2022-03-31 | 2022-03-31 | Novel annular anti-crack test device of concrete restraint shrinkage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217466923U (en) |
-
2022
- 2022-03-31 CN CN202220731620.2U patent/CN217466923U/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104931348B (en) | Annulus radial compression energy predicting material single shaft constitutive relation assay method | |
| CN101122596B (en) | Concrete cracking sensitivity test device and anti-crack ability evaluation method | |
| CN108627401B (en) | Concrete early-age temperature stress test equipment and method based on torus method | |
| CN107607412B (en) | A kind of concrete structure combined type strain monitoring unit and its state evaluating method | |
| CN106596100B (en) | A kind of four-step machine tool chief axis elasticity modulus lossless detection method and device | |
| CN104345093A (en) | Method for detecting elastic modulus of concrete material in reinforced concrete member | |
| CN102866245A (en) | Test method and test device for unrestraint measurement of concrete deformation performance | |
| Gao et al. | Rate effect on the stress–strain behavior of concrete under uniaxial tensile stress | |
| CN110907632A (en) | Large-volume concrete cracking early warning system and method | |
| CN101620042A (en) | Method for detecting compressive strength of concrete by body sampling | |
| CN100560875C (en) | The retrofit testing method of single-pile vertical orientation resistance to plucking static loading test | |
| CN217466923U (en) | Novel annular anti-crack test device of concrete restraint shrinkage | |
| Ye et al. | Master S-N Curve-Based Fatigue Life Assessment of Steel Bridges Using Finite Element Model and Field Monitoring Data | |
| CN208847736U (en) | A kind of test device of quick measurement concrete early-stage crack resistance | |
| Karadogan et al. | A novel and simple cruciform specimen without slits on legs yet higher plastic strains in gauge | |
| Yost et al. | Using NDT data for finite element model calibration and load rating of bridges | |
| CN216433861U (en) | Range finding adjustable reinforcing bar corrosion magnetic induction sensor | |
| CN106596299A (en) | Concrete dynamic direct tensile test device and method based on drop hammer test | |
| Zhong et al. | Structural behaviour and resistances of high strength concrete-filled stainless steel tube (HCFSST) beam-columns | |
| JP4498962B2 (en) | Method for measuring internal strain of concrete structure and concrete structure | |
| CN113916408A (en) | Method for measuring internal stress of concrete structure | |
| CN106769561A (en) | A kind of lower Hollow Transmission Shafts mechanics parameter lossless detection method of temperature loading effect | |
| Wu | Behavior of High-Strength Concrete Members under Pure Flexure and Axial-Flexural Loading | |
| CN100442007C (en) | Method and structure for measuring thin-membrane strain | |
| CN111400956A (en) | Beam member equivalent bending rigidity testing method based on corner |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20220920 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |