CN107238526B - Device for reducing deformation of precast cracks caused by concrete shrinkage - Google Patents
Device for reducing deformation of precast cracks caused by concrete shrinkage Download PDFInfo
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- CN107238526B CN107238526B CN201710428076.8A CN201710428076A CN107238526B CN 107238526 B CN107238526 B CN 107238526B CN 201710428076 A CN201710428076 A CN 201710428076A CN 107238526 B CN107238526 B CN 107238526B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/36—Embedding or analogous mounting of samples
Abstract
The invention relates to a device for reducing deformation of a prefabricated crack caused by concrete shrinkage. The oil pressure measuring device comprises an end plate, a front side plate, a rear side plate, a bottom plate, a nut, a transverse pull rod, a longitudinal pull rod, a T-shaped body positioning groove, a T-shaped body, an oil inlet valve, an oil outlet valve, a loading device, an oil pressure meter and an oil pipe. Has the characteristics of simple operation, convenience, high efficiency and the like.
Description
Technical Field
The invention relates to a device for reducing deformation of a prefabricated crack caused by concrete shrinkage, and belongs to the technical field of concrete fracture mechanical property testing.
Background
DL/T5332-2005 'Hydraulic engineering concrete fracture test procedure' proposes that the fracture parameters of concrete are tested by a wedging splitting method and a three-point bending beam method. Compared with the wedge splitting method, the three-point bending beam method is easier to obtain a stable test curve, and therefore, the three-point bending beam method is widely used. When three-point bending beam prefabricated cracks are manufactured, the main methods used at present are a prefabricated notching method and a cutting notching method. The cutting-and-slitting method mainly aims at plain concrete, and if materials such as steel fibers are added into the concrete, slits meeting the test requirements are difficult to cut, so the pre-slitting method is widely used.
When the prefabricated incision method is used for manufacturing the concrete three-point bending incision beam, normally, a steel sheet with prefabricated incisions is directly fixed on a test mold, a layer of mineral oil is smeared on the inner surfaces of two sides of the steel sheet, the steel sheet is pulled out within 3 hours after the concrete is initially set to form cracks, and after the steel sheet is pulled out, the cracks are inevitably deformed due to the shrinkage of the concrete. Because the concrete shrinkage duration is very long, and sometimes even more than half a year, in order to reduce the deformation of the precast cracks caused by the concrete shrinkage, the steel sheet extraction time needs to be prolonged, for example, the concrete is cured with a mold, and after the curing time is reached, the steel sheet is extracted, but the steel sheet is extruded when the concrete shrinks, so that the steel sheet is difficult to extract due to the fact that the steel sheet is extruded when the concrete shrinks, and the precast cracks are disturbed due to forced extraction, and the test result is affected.
Disclosure of Invention
The present invention provides a means for reducing the deformation of a pre-cast crack caused by concrete shrinkage. The device can reduce the problem of deformation of the prefabricated crack caused by concrete shrinkage, and has the characteristics of simplicity in operation, convenience, high efficiency and the like.
The technical scheme of the invention is realized as follows:
the utility model provides a reduce and arouse device that prefabricated crack warp by concrete contraction, includes end plate, preceding curb plate, posterior lateral plate, bottom plate, nut, horizontal pull rod, vertical pull rod, T physique constant head tank, T physique, inlet valve, delivery valve, loading device, fuel pressure gauge and oil pipe and constitutes, horizontal pull rod is used for connecting preceding curb plate and posterior lateral plate, vertical pull rod is used for connecting bottom plate and horizontal pull rod, the nut is used for connecting horizontal pull rod, vertical pull rod, preceding curb plate and posterior lateral plate, interconnect forms three point bending beam device main part between end plate, preceding curb plate, posterior lateral plate, bottom plate, nut, horizontal pull rod, the vertical pull rod, it has T physique constant head tank to open on the preceding curb plate, T physique can block on T physique constant head tank, the T physique comprises wedge and card body, the wedge internal portion has opened the room, be equipped with inlet port and delivery port between oil pressure chamber and the wedge body upper surface, inlet valve and outlet valve are located the oil pipe of being connected with inlet port and delivery port respectively, the fuel pressure gauge is located on the oil pipe between loading device and the inlet valve.
Preferably, the end plate, the front side plate, the rear side plate, the bottom plate, the nut, the transverse pull rod and the longitudinal pull rod are all made of Q235 steel materials, and the T-shaped body is made of ABS plastic materials.
Compared with the prior art, the invention has the beneficial effects that:
1. the wedge-shaped body is internally provided with an oil pressure chamber, oil pressure can be applied to the oil pressure chamber through an oil pressure loading device, and relative stress balance is formed between the oil pressure chamber and the concrete shrinkage stress, so that the defect that the T-shaped body is difficult to pull out due to the fact that the T-shaped body is clamped due to concrete shrinkage is overcome, after the required time is reached, the oil pressure is removed, the T-shaped body can be easily pulled out, the defect that prefabricated cracks are disturbed when the T-shaped body is forcibly pulled out due to the fact that the T-shaped body is clamped is overcome, therefore, the T-shaped body pulling-out time can be prolonged on the premise that the T-shaped body is guaranteed to be easily pulled out, and prefabricated crack deformation caused by concrete shrinkage is reduced.
In conclusion, by adopting the device, on one hand, the pulling-out time of the T-shaped body can be prolonged, so that the deformation of the prefabricated crack caused by the shrinkage of concrete is reduced, and on the other hand, the T-shaped body can be easily pulled out after the pulling-out time is prolonged;
2. because the T-shaped body is made of ABS plastic material, the friction force between the T-shaped body and concrete is small, and the T-shaped body can be pulled out more easily after the specified time.
Drawings
Fig. 1 is a perspective view of the inventive device.
Figure 2 is a schematic view of the T-shaped body of the present invention captured in the T-shaped body positioning slot.
FIG. 3 is a schematic view of the T-body oil pressure loading system of the present invention.
Fig. 4 is a schematic view of a wedge of the present invention.
The numbering in the figures illustrates: 1-end plate, 2-front side plate, 3-back side plate, 4-bottom plate, 5-nut, 6-transverse pull rod, 7-longitudinal pull rod, 8-T body positioning groove, 9-T body, 10-oil inlet valve, 11-oil outlet valve, 12-loading device, 13-oil pressure gauge, 14-oil pipe, 15-oil inlet hole, 16-oil outlet hole, 17-oil pressure chamber, 91-wedge body and 92-clamping body.
Detailed Description
The invention will be described in further detail with reference to the following drawings and specific embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
referring to fig. 1-4, the device for reducing deformation of precast cracks caused by concrete shrinkage is shown as a schematic diagram, and the device is composed of an end plate 1, a front side plate 2, a rear side plate 3, a bottom plate 4, a nut 5, a transverse pull rod 6, a longitudinal pull rod 7, a T-shaped body positioning groove 8, a T-shaped body 9, an oil inlet valve 10, an oil outlet valve 11, a loading device 12, an oil pressure gauge 13 and an oil pipe 14. Horizontal pull rod 6 is used for connecting preceding curb plate 2 and posterior lateral plate 3, vertical pull rod 7 is used for connecting bottom plate 4 and horizontal pull rod 6, nut 5 is used for connecting horizontal pull rod 6, vertical pull rod 7, preceding curb plate 2 and posterior lateral plate 3, interconnect forms three point bending beam device main part between end plate 1, preceding curb plate 2, posterior lateral plate 3, bottom plate 4, nut 5, horizontal pull rod 6, the vertical pull rod 7, it has T physique constant head tank 8 to open on the preceding curb plate 2, T physique 9 can block on T physique constant head tank 8, T physique 9 comprises wedge 91 and card body 92, the inside oil pressure room 17 that has opened of wedge 91, be equipped with inlet port 15 and outlet port 16 between oil pressure room 17 and the upper surface of wedge 91, inlet valve 10 and outlet valve 11 are located the oil pipe 14 that links to each other with inlet port 15 and outlet port 16 respectively, oil pressure table 13 is located the oil pipe 14 between loading device 12 and the inlet valve 10. The end plate 1, the front side plate 2, the rear side plate 3, the bottom plate 4, the nut 5, the transverse pull rod 6 and the longitudinal pull rod 7 are all made of Q235 steel materials, and the T-shaped body 9 is made of ABS plastic materials.
The specific operation steps are as follows:
(a) Assembly of three-point bending beam device main body
As shown in fig. 1, an end plate 1, a front side plate 2, a rear side plate 3, a bottom plate 4, a nut 5, a transverse pull rod 6 and a longitudinal pull rod 7 are connected with each other, the transverse pull rod 6 is used for connecting the front side plate 2 and the rear side plate 3, the longitudinal pull rod 7 is used for connecting the bottom plate 4 and the transverse pull rod 6, and the nut 5 is used for connecting the transverse pull rod 6, the longitudinal pull rod 7, the front side plate 2 and the rear side plate 3 to form a main body of the three-point bending beam device.
(b) Assembly of T-shaped 9 oil pressure loading system
As shown in fig. 2 to 4, the T-shaped body 9 is composed of a wedge-shaped body 91 and a clamp body 92, the oil inlet valve 10 and the oil outlet valve 11 are respectively installed on the oil pipe 14 connected with the oil inlet hole 15 and the oil outlet hole 16, the oil pressure gauge 13 is installed on the oil pipe 14 between the loading device 12 and the oil inlet valve 10, and the T-shaped body 9 is clamped in the T-shaped body positioning groove 8.
(c) Preparation of concrete three-point bending beam test piece
A layer of mineral oil is smeared on the inner side of a main body of the three-point bending beam device and the outer side of the T-shaped body 9, concrete which is well mixed according to the design mixing proportion is placed into the device, the surface of the concrete is leveled, at the moment, the oil inlet valve 10 is opened, the oil outlet valve 11 is closed, the loading device 12 is started, certain pressure is formed in the oil pressure chamber 17 in the wedge-shaped body 91, the pressure value can be read by the oil pressure meter 13, and the size of the pressure value can be adjusted according to the size of the shrinkage stress of the concrete.
(d) Mould for removing concrete three-point bending beam test piece
After 3h of initial setting of concrete, the mold can be temporarily not removed, at this time, in general, the stress borne by the T-shaped body 9 is increased due to the shrinkage of the concrete, and the T-shaped body 9 is difficult to pull out after the mold is removed, however, by adopting the device disclosed by the invention, because a certain pressure is arranged in the oil pressure chamber 17 in the wedge-shaped body 91, stress balance can be formed with the shrinkage stress of the concrete, so that the T-shaped body 9 is not easy to pull out due to the shrinkage stress of the concrete, then the concrete can be cured, after the specified curing time (such as 28 days) is reached, the oil inlet valve 10 is closed, the oil outlet valve 11 is opened, the pressure in the wedge-shaped body 91 is unloaded, at this time, the T-shaped body 9 can be easily pulled out of the T-shaped body positioning groove 8, then the nut 5, the transverse pull rod 6 and the longitudinal pull rod 7 are sequentially removed, and the concrete three-point bending beam test piece is taken out for carrying out to carry out the concrete fracture performance test.
Claims (2)
1. The utility model provides a reduce and arouse device that prefabricated crack warp by concrete contraction, includes end plate, preceding curb plate, posterior lateral plate, bottom plate, nut, horizontal pull rod, vertical pull rod, T physique constant head tank, T physique, inlet valve, delivery valve, loading device, fuel pressure gauge and oil pipe and constitutes, horizontal pull rod is used for connecting preceding curb plate and posterior lateral plate, vertical pull rod is used for connecting bottom plate and horizontal pull rod, the nut is used for connecting horizontal pull rod, vertical pull rod, preceding curb plate and posterior lateral plate, interconnect forms three point bending beam device main part between end plate, preceding curb plate, posterior lateral plate, bottom plate, nut, horizontal pull rod, the vertical pull rod, its characterized in that, it has T physique constant head tank to open on the preceding curb plate, T physique can block on T physique constant head tank, T physique comprises oil pipe and the card body, the internal portion of wedge has the sealed oil pressure room, be equipped with inlet port and delivery port between sealed oil pressure chamber and the wedge body upper surface, inlet valve and delivery valve are located the oil pipe that is connected with inlet port and delivery valve respectively, oil pressure gauge is located loading device and valve between the oil pressure gauge.
2. The apparatus for reducing deformation of a prepared crack caused by concrete shrinkage as set forth in claim 1, wherein: the end plate, the front side plate, the rear side plate, the bottom plate, the nut, the transverse pull rod and the longitudinal pull rod are all made of Q235 steel materials, and the T-shaped body is made of ABS plastic materials.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710428076.8A CN107238526B (en) | 2017-06-08 | 2017-06-08 | Device for reducing deformation of precast cracks caused by concrete shrinkage |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710428076.8A CN107238526B (en) | 2017-06-08 | 2017-06-08 | Device for reducing deformation of precast cracks caused by concrete shrinkage |
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| CN107238526A CN107238526A (en) | 2017-10-10 |
| CN107238526B true CN107238526B (en) | 2023-03-24 |
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| CN108680407A (en) * | 2018-03-22 | 2018-10-19 | 扬州大学 | A kind of cutter device for concrete notch beam test |
| CN109781518B (en) * | 2019-01-11 | 2021-09-28 | 东南大学 | II-type fracture test fixture for viscoelastic material on microscopic scale and test method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4448002A (en) * | 1979-08-13 | 1984-05-15 | Restra Patentverwertung Gmbh | End-anchoring device for anchoring at least one bar made from a fibrous compound material and being used as tendon in pre-stressed concrete construction |
| CN104165838A (en) * | 2014-08-08 | 2014-11-26 | 太原理工大学 | Impact drawing experimental device and experimental method |
| CN204188427U (en) * | 2014-04-01 | 2015-03-04 | 西北农林科技大学 | A kind of test block shaping dies for testing concrete by three-point bending energy to failure |
| CN205656080U (en) * | 2016-03-29 | 2016-10-19 | 沈阳工业大学 | Three -point bending test device of test concrete breaking property ability |
-
2017
- 2017-06-08 CN CN201710428076.8A patent/CN107238526B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4448002A (en) * | 1979-08-13 | 1984-05-15 | Restra Patentverwertung Gmbh | End-anchoring device for anchoring at least one bar made from a fibrous compound material and being used as tendon in pre-stressed concrete construction |
| CN204188427U (en) * | 2014-04-01 | 2015-03-04 | 西北农林科技大学 | A kind of test block shaping dies for testing concrete by three-point bending energy to failure |
| CN104165838A (en) * | 2014-08-08 | 2014-11-26 | 太原理工大学 | Impact drawing experimental device and experimental method |
| CN205656080U (en) * | 2016-03-29 | 2016-10-19 | 沈阳工业大学 | Three -point bending test device of test concrete breaking property ability |
Non-Patent Citations (1)
| Title |
|---|
| 混凝土断裂特性的实验研究;代祥俊等;《山东理工大学学报(自然科学版)》;20051030(第05期);全文 * |
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