Loosening-preventing concrete longitudinal limiter

Abstract

The utility model provides an anti-loosening concrete longitudinal limiter, which belongs to the technical field of engineering construction and comprises a group of end plates and longitudinal limiting steel bars. The two ends of the longitudinal limiting steel bar are fixedly connected with end plates. The longitudinal limiting steel bar penetrates through the end plates and then is fixedly connected with a measuring device. And a plurality of limiting pieces are arranged on the inner sides of the end plates. According to the utility model, the limiting pieces are respectively arranged on the inner side surfaces of the end plates, so that the concrete test block and the longitudinal limiting steel bars can be prevented from moving relatively even if the concrete test block is disturbed by external force in the processes of stripping the concrete, carrying the test block and measuring the initial length, and the effectiveness of an experiment and the accuracy of measured data are ensured.

Description

Technical Field

[0001] This utility model relates to the field of engineering construction technology, and in particular to a longitudinal restraint for preventing loosening of concrete. Background Technology

[0002] Concrete expansive agents are widely used in crack-resistant concrete, and their key technical indicator is the restricted expansion rate. The restricted expansion rate is an important indicator for concrete expansive agent manufacturers, users, and third-party testing agencies to determine the quality of expansive agents. Therefore, accurate and efficient measurement of the restricted expansion rate is crucial for controlling the quality of expansive concrete.

[0003] The current national standard GB / T23439-2017 "Concrete Expansion Agent" Appendix B specifies the test method for the restricted expansion rate of concrete and the construction of the longitudinal restraint. During molding, concrete is poured into a mold containing the longitudinal restraint. After the concrete reaches its demolding strength, it is demolded, and the initial length and length at various ages of the concrete specimen are measured by comparison with a standard rod. On the one hand, the surfaces of the two end plates of the longitudinal restraint are smooth and coated with a release agent, and the expansion energy release of the expansion agent is very limited in the early stage of demolding, resulting in low friction between the ends of the concrete specimen and the two end plates of the longitudinal restraint. On the other hand, under the demolding strength of 3MPa to 5MPa, the bond strength between the concrete and the longitudinal restraining reinforcement is limited. If the concrete specimen is disturbed by external forces during demolding, specimen handling, and initial length measurement, the concrete specimen and the longitudinal restraining reinforcement are prone to loosening, causing significant measurement deviations, or even invalid data leading to experimental failure. Utility Model Content

[0004] This invention provides a concrete longitudinal restraint to prevent loosening, thereby overcoming the shortcomings of existing longitudinal restraints and ensuring that the concrete test block and the longitudinal restraint are always a single unit.

[0005] This utility model provides a concrete longitudinal restraint to prevent loosening, comprising: a set of end plates and longitudinal restraining bars; both ends of the longitudinal restraining bars are fixedly connected to the end plates, and the longitudinal restraining bars pass through the end plates and are fixedly connected to a measuring device; multiple limiting members are provided on the inner side of the end plates.

[0006] According to the present invention, a concrete longitudinal restraint for preventing loosening is provided, wherein the limiting member is an anchor head, and a plurality of the anchor heads are respectively fixed on opposite sides of the end plate.

[0007] According to the present invention, a concrete longitudinal restraint for preventing loosening is provided, wherein the number of anchor nail heads is four, which are respectively fixed on two end plates.

[0008] According to the present invention, a longitudinal concrete restraint for preventing loosening is provided, wherein the anchor head is a cylinder, the length and diameter of the anchor head are both 5mm, and two anchor heads are symmetrically distributed on the inner side of the end plate.

[0009] According to the present invention, a longitudinal concrete restraint for preventing loosening is provided, wherein the longitudinal restraining steel bar has a diameter of 10 mm and a cross-sectional area of ​​78.54 mm². 2 .

[0010] According to the present invention, a longitudinal concrete restraint for preventing loosening is provided, wherein the end plate has a length and width of 100mm and a thickness of 12mm.

[0011] According to the present invention, a longitudinal concrete restraint for preventing loosening is provided, wherein the measuring device is a measuring head.

[0012] According to the present invention, a longitudinal limiter for preventing loosening of concrete is provided, wherein the measuring head is made of brass or stainless steel.

[0013] According to the present invention, a concrete longitudinal restraint for preventing loosening is provided, wherein the measuring head is located within 7.5 mm of the center point of the end of the longitudinal restraining rebar.

[0014] According to the present invention, a longitudinal concrete restraint for preventing loosening is provided, wherein the measuring head is spherical with a radius of 3mm.

[0015] The concrete longitudinal restraint provided by this utility model, by providing limiting components on the inner side of the end plate, ensures that the concrete test block and the longitudinal restraining reinforcement do not move relative to each other even when subjected to external force disturbance during concrete demolding, test block handling, and initial length measurement, thus ensuring the effectiveness of the experiment and the accuracy of the measurement data. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural schematic diagram of the concrete longitudinal restraint provided by this utility model to prevent loosening.

[0018] Figure label:

[0019] 1. Limiting component; 2. Longitudinal limiting reinforcement; 3. End plate; 4. Measuring device. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" indicate the direction or positional relationship, which is usually based on Figure 1 The orientation and position of the concrete longitudinal restraint shown for preventing loosening when normally placed are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model; the directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0024] This utility model provides a longitudinal restraint for preventing loosening of concrete, see [link to related document]. Figure 1 It includes: a set of end plates 3 and longitudinal limiting steel bars 2; both ends of the longitudinal limiting steel bars 2 are fixedly connected to the end plates 3, and the longitudinal limiting steel bars 2 are fixedly connected to the measuring device 4 after passing through the end plates 3; multiple limiting pieces 1 are provided on the inner side of the end plates 3.

[0025] By providing limiting elements 1 on the inner side of the end plate 3, even if the concrete specimen is disturbed by external forces during concrete demolding, specimen handling, and initial length measurement, the relative movement between the concrete specimen and the longitudinal limiting steel bar 2 can be ensured, thus ensuring the effectiveness of the experiment and the accuracy of the measurement data.

[0026] In one embodiment, the limiting member 1 is an anchor head, and multiple anchor heads are respectively fixed on opposite sides of the end plate 3.

[0027] In one embodiment, there are four anchor heads, which are fixed on two end plates 3 respectively.

[0028] In one embodiment, the anchor head is a cylinder with a length and diameter of 5 mm, and two anchor heads are symmetrically distributed on the inner side of the end plate 3.

[0029] For example, the material of the anchor head conforms to the technical requirements of GB / T700.

[0030] In one embodiment, the longitudinal restraining steel bar 2 has a diameter of 10 mm and a cross-sectional area of ​​78.54 mm². 2 .

[0031] For example, the longitudinal restraint reinforcement 2 is the type of reinforcement specified in GB / T1499.2.

[0032] In one embodiment, the end plate 3 has a length and width of 100 mm and a thickness of 12 mm.

[0033] For example, the material of end plate 3 conforms to the technical requirements of GB / T700.

[0034] In one embodiment, the measuring device 4 is a measuring head. The measuring head is made of brass or stainless steel. The measuring head is located within 7.5 mm of the center point of the end of the longitudinal restraining rebar 2. The measuring head is spherical with a radius of 3 mm.

[0035] In one embodiment, the anchor head is welded to the end plate 3, and the longitudinal restraining steel bar 2 is welded to the measuring head and the end plate 3, with a welding strength not less than 260 MPa.

[0036] The existing longitudinal restraints have smooth end plates 3 with a release agent applied to their surfaces. In the early stages of demolding, the expansion energy release of the expansion agent is limited, resulting in low friction between the concrete specimen ends and the end plates 3. Under demolding strength conditions of 3MPa–5MPa, the bond strength between the concrete and the longitudinal restraint reinforcement 2 is limited. If disturbed by external forces during demolding, specimen handling, and initial length measurement, the concrete specimen and the longitudinal restraint reinforcement 2 can easily loosen, causing significant measurement deviations or even invalid data leading to experimental failure. This application addresses this by providing four anchoring nail heads on the inner side of the end plates 3. Even if disturbed by external forces during demolding, specimen handling, and initial length measurement, this ensures that the concrete specimen and the longitudinal restraint reinforcement 2 do not move relative to each other, guaranteeing the validity of the experiment and the accuracy of the measurement data.

[0037] The specific usage method is as follows: Before molding the test block, place this device into the concrete restricted expansion rate mold, pour the mixed concrete into the mold at once, and then place the mold on a vibrating table to vibrate until the surface shows cement paste. Scrape off the excess concrete and smooth it. Then place the specimen in an indoor environment with a temperature of 20℃±3℃ for curing. Cover the surface of the specimen with plastic sheeting or a damp cloth to prevent moisture evaporation. When the compressive strength of the freely expanding concrete reaches 3MPa~5MPa, remove the mold and measure the initial length of the specimen. Due to the anchoring effect of the four anchor nail heads symmetrically distributed on the inner side of the end plate 3 and the concrete, the concrete specimen and the longitudinal restricting steel bar 2 will not move relative to each other during the demolding, handling, and initial length measurement of the concrete specimen, ensuring that the concrete specimen and the longitudinal restrictor are always a whole. When measuring the length of the specimen at the corresponding age (e.g., 3 days, 7 days, 14 days, 28 days, etc.), the direction and position of the specimen must be fixed and consistent with those when measuring the initial length, and should not be changed arbitrarily. The length of each specimen should be measured three times, and the stable value should be taken.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A loose concrete longitudinal restraint, characterized in that, The utility model relates to a kind of longitudinal restriction reinforcement measuring device, including: A set of end plate and longitudinal restriction reinforcement;Two ends of the longitudinal restriction reinforcement are fixedly connected with the end plate, and the longitudinal restriction reinforcement is fixedly connected with measuring device after passing through the end plate;Multiple limiters are arranged in the inside of the end plate.

2. The loose concrete longitudinal restraint according to claim 1, wherein, The limiter is anchor nail head, and multiple anchor nail heads are fixed on the opposite side of the end plate respectively.

3. The loose concrete longitudinal restraint according to claim 2, wherein, The number of anchor nail head is 4, and is fixed on two end plates respectively.

4. The loose concrete preventing longitudinal restrainer according to claim 3, wherein The anchor nail head is cylinder, and the length and diameter of the anchor nail head are both 5mm, and two anchor nail heads are symmetrically distributed on the inside of the end plate.

5. The loose concrete preventing longitudinal restrainer according to claim 1, wherein The longitudinal limit reinforcement has a diameter of 10 mm and a cross-sectional area of 78.54 mm 2 .

6. The loose concrete preventing longitudinal restrainer according to claim 1, wherein The length and width of the end plate are both 100mm, and the thickness is 12mm.

7. The loose concrete preventing longitudinal restrainer according to claim 1, wherein The measuring device is measuring head.

8. The loose concrete longitudinal restraint of claim 7, wherein, The measuring head is brass or stainless steel.

9. The loose concrete longitudinal restraint of claim 8, wherein, The measuring head is located within 7.5mm of the center point of the end of the longitudinal restriction reinforcement.

10. The loose concrete longitudinal restraint of claim 8, wherein, The measuring head is spherical, and the radius is 3mm.

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