Device for measuring restrained expansion rate of expansive concrete

Abstract

The measuring device comprises a left end plate and a right end plate, and is characterized in that the periphery of the inner side of the left end plate is fixedly connected with the periphery of the inner side of the right end plate through four limiting steel bars which are uniformly distributed, strain sensors are arranged on the limiting steel bars, and wire pipe round holes are formed in the middle parts of the left end plate and the right end plate; a threading pipe penetrates into the round hole of the wire pipe, an inner cavity of the threading pipe forms a wire outlet cavity, and the middle part of the threading pipe is provided with a wire inlet hole into which a signal wire of the strain sensor penetrates; and a signal wire of the strain sensor penetrates into the wire outlet cavity through the wire inlet hole and is led out. The measuring device disclosed by the utility model is provided with the four strain sensors, so that the test data of the restrained expansion rate of the expansive concrete is more accurate, and the problem that the measuring result is inaccurate or cannot be measured due to the defects of the sensors is avoided; a signal line of the strain sensor is led out through the threading pipe, so that the influence of expansive concrete on the signal line is avoided.

Description

Technical Field

[0001] The utility model relates to a measuring device, and more specifically, to a measuring device for the restricted expansion rate of expansive concrete. Background Technique

[0002] With the rapid development of China's economy, there are more and more new buildings and new structures. Among them, a lot of reinforced concrete structures use expansive concrete. For example, in the expansion joints between precast prestressed concrete slabs of reinforced concrete used as road surface or base parts, longitudinal bars and transverse bars are provided in the expansion joints and expansive concrete is poured. At this time, in order to accurately calculate the longitudinal pressure generated by the expansive concrete in the expansion joints, it is necessary to measure the restricted expansion rate of the used expansive concrete. However, the existing specification in China for measuring expansive concrete is the dial gauge method. Sometimes we need to continuously measure data, such as detecting the expansion performance of expansive concrete for 7 days, 14 days, 1 month, 1 year, 12 years, 20 years or even longer. It is obviously impossible to achieve relying on the current dial gauge method.

[0003] Although there are also measurement tools for the restricted expansion rate that abandon the dial gauge currently. Its structure is to fix a strain sensor on the ribbed steel bar, and pour the ribbed steel bar provided with the strain sensor into the expansive concrete specimen to achieve the measurement of the restricted expansion rate of the concrete. However, in this measurement method, due to the use of a single strain sensor, it is required that the installation position of the ribbed steel bar is very precise, otherwise it will affect the measurement accuracy. Moreover, when the strain sensor itself fails or has low accuracy, it will seriously affect the measurement result. Moreover, in this measurement method, the signal wire of the sensor directly penetrates out of the concrete, which will not only affect the reinforcement ratio, but also may cause damage to the signal wire or affect the measurement accuracy. Summary of the Invention

[0004] The utility model aims to overcome the above-mentioned technical problems and provides a measuring device for the restricted expansion rate of expansive concrete.

[0005] The measuring device for the restricted expansion rate of the expansive concrete of the utility model includes a left end plate and a right end plate arranged in parallel with each other. The space between the left end plate and the right end plate is used for pouring the expansive concrete to be tested. The characteristics are as follows: the four sides inside the left end plate are fixedly connected to the four sides inside the right end plate through 4 uniformly distributed restraint steel bars. Strain sensors for detecting the expansion and contraction amount of the restraint steel bars are arranged on the restraint steel bars. Tube holes are opened in the middle parts of the left end plate and the right end plate. A wiring pipe penetrates into the tube holes. The internal cavity of the wiring pipe forms an outlet cavity. An inlet hole for the signal wire of the strain sensor to penetrate into is opened in the middle part of the wiring pipe. The signal wire of the strain sensor penetrates into the outlet cavity through the inlet hole and is led out.

[0006] The utility model discloses a measuring device for limiting expansion rate of expansive concrete, wherein the four limiting steel bars are fixedly connected to the inner sides of the left end plate and the right end plate by welding, and the welding points between the four limiting steel bars and the left end plate or the right end plate are located at the vertices of a square with the center of the left end plate or the right end plate as the midpoint.

[0007] The utility model discloses a measuring device for limiting expansion rate of expansive concrete, comprising a casting mold for assisting in casting expansive concrete between a left end plate and a right end plate, the casting mold is composed of a bottom plate and two side plates fixed on both sides of the bottom plate, a casting cavity is formed between the bottom plate and the two side plates, the cross-sectional shape of the casting cavity is consistent with the left end plate and the right end plate, and both ends of the two side plates are provided with inward folding limit plates for limiting the left end plate and the right end plate respectively.

[0008] The utility model discloses a measuring device for limiting expansion rate of expansive concrete, wherein the left end plate and the right end plate are squares with equal sides, the left end plate and the right end plate are steel plates with sides of 17.7 cm and a thickness of 1.5 cm, and the diameter of the circular hole of the wire tube is 1 cm.

[0009] The utility model discloses a measuring device for limiting expansion rate of expansive concrete. The limiting steel bar adopts HRB335 hot-rolled ribbed steel bar with a diameter of 10 mm, and the threading pipe adopts a plastic pipe with an outer diameter of 1 cm.

[0010] In the measuring device for limiting expansion rate of expansive concrete of the utility model, the distance between the inner wall of the left end plate and the inner wall of the right end plate is 53.10 cm.

[0011] The utility model discloses a device for measuring the expansion rate of expansion concrete. A paraffin layer is applied between the threading tube (5) and the inner wall of the circular hole of the wire tube to prevent the expansion concrete slurry from bubbling out.

[0012] The beneficial effects of the utility model are as follows: the measuring device for the limited expansion rate of expansive concrete of the utility model has a left end plate and a right end plate which are parallel to each other and connected via four uniformly distributed limiting steel bars, the limiting steel bars are provided with strain sensors, and the signal lines of the strain sensors are inserted into a threading tube and led out. Therefore, compared with the existing testing device for the limited expansion rate of expansive concrete, since four limiting steel bars and four strain sensors are provided, the maximum and minimum values ​​are removed during measurement, and the remaining two values ​​are averaged, so that the test data of the limited expansion rate of expansive concrete is more accurate, and the problem of inaccurate measurement results or inability to measure due to defects of the sensor itself is avoided; at the same time, the signal line of the strain sensor is led out via the threading tube, instead of being directly passed out from the poured expansive concrete in the existing method, while avoiding the influence of the expansive concrete on the signal line, the accuracy of the measurement data is further guaranteed.

[0013] Furthermore, four limiting steel bars are welded at the vertices of a square with the center of the left end plate or the right end plate as the midpoint, so that during the expansion of the expansive concrete, each limiting steel bar is subjected to uniform force and has substantially consistent deformation, thereby ensuring the accuracy of the measurement results.

[0014] Furthermore, a casting mold is provided to assist in casting expansive concrete between the left end plate and the right end plate. When in use, the left end plate and the right end plate are placed in the casting cavity of the casting mold, and the inner limiting plate is used to limit the left and right end plates. Then, the expansive concrete is cast. After the expansive concrete has initially solidified for 4 to 6 hours, the casting mold can be removed, thereby facilitating the casting of the expansive concrete between the left and right end plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view of the measuring device for limiting the expansion rate of expansive concrete of the utility model;

[0016] Figure 2 It is a left view of the measuring device for limiting expansion rate of expansive concrete of the utility model;

[0017] Figure 3 It is a three-dimensional diagram of the casting mold in the utility model;

[0018] Figure 4 This is a state diagram of the device for measuring the limiting expansion rate of expansive concrete of the utility model when pouring expansive concrete.

[0019] In the figure: 1 left end plate, 2 right end plate, 3 limiting steel bar, 4 strain sensor, 5 wire threading tube, 6 wire tube round hole, 7 welding point, 8 wire entry hole, 9 signal wire, 10 wire outlet cavity, 11 casting mold, 12 bottom plate, 13 side plate, 14 casting cavity, 15 inner folding limit plate. DETAILED DESCRIPTION

[0020] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0021] like Figure 1 and Figure 2 As shown, the front view and the left view of the measuring device for limiting expansion rate of expansive concrete of the utility model are respectively given. The measuring device for limiting expansion rate of expansive concrete shown is composed of a left end plate 1, a right end plate 2, limiting steel bars 3, a strain sensor 4 and a threading tube 5. The left end plate 1 and the right end plate 2 are parallel to each other and aligned. The number of limiting steel bars 3 is 4, and the 4 limiting steel bars 3 are evenly distributed. The two ends of the 4 limiting steel bars 3 are respectively welded on the inner side surfaces of the left end plate 1 and the right end plate 2. A strain sensor 4 is fixed on each limiting steel bar 3. The strain sensor 4 is used to measure the deformation of the limiting steel bar 3. The measurement signal of the strain sensor 4 is transmitted through the signal line 9.

[0022] At the central positions of the left end plate 1 and the right end plate 2 shown, wire tube round holes 6 are provided. The wire threading tube 5 penetrates into the wire tube round holes 6, and both ends of the wire threading tube 5 are flush with the left end plate 1 and the right end plate 2; the internal cavity of the wire threading tube 5 forms an outgoing line cavity 10. An incoming line hole 8 is provided in the middle of the wire threading tube 5, corresponding to the four strain sensors 4, and the number of incoming line holes 8 can also be set to 4. The signal wires of the strain sensors 4 penetrate into the outgoing line cavity 10 inside the wire threading tube 5 through the incoming line holes 8 and are led out, thereby realizing the acquisition of the signals measured by the strain sensors 4.

[0023] For the measuring device of the restricted expansion rate of expansive concrete of the present utility model, since four restraint steel bars 3 are provided between the left end plate 1 and the right end plate 2, and strain sensors 4 are provided on each display steel bar 3, when the expansive concrete is poured, by collecting the measurement signals of the four strain sensors 4, and the maximum value and the minimum value can be discarded, and the restricted expansion rate of the expansive concrete can be obtained by taking the average of the middle two values. Compared with the existing single restraint steel bar 3 and single strain sensor 4, the problem of measurement result failure or inaccuracy caused by the failure of the strain sensor 4 itself can be solved.

[0024] At the same time, the signal wires 9 of the strain sensors 4 are led out in a standardized manner through the pipeline tube 5 poured in the center of the expansive concrete, rather than the existing way of directly passing through the expansive concrete. In this way, the adverse effect of the expansive concrete on the signal wires 9 during the expansion process can be avoided, further ensuring the accuracy of the measurement data.

[0025] In order to facilitate the pouring of the expansive concrete between the left end plate 1 and the right end plate 2, a pouring mold 11 for assisting in pouring the expansive concrete is also provided, as Figure 3 and Figure 4 shown. The perspective view of the pouring mold in the present utility model and the state diagram when using it to pour the expansive concrete are respectively given. The shown pouring mold 11 is composed of a bottom plate 12 and two side plates 13 fixed on both sides of the bottom plate 12. The cross-section of the pouring mold 11 is U-shaped with an open upper end for pouring the concrete. A pouring cavity 14 for accommodating the measuring device is formed between the bottom plate 12 and the two side plates 13, and the cross-sectional shape of the pouring cavity 14 is the same as that of the left end plate 1 and the right end plate 2 so that the left end plate 1 and the right end plate 2 can be placed into the pouring cavity 14.

[0026] Inner folding limit plates 15 are provided at both ends of the shown two side plates 13. The inner folding limit plates 15 realize the limitation of the left end plate 1 and the right end plate 2 to prevent them from moving outwards. During use, the left end plate 1 and the right end plate 2 are placed into the pouring cavity 14, and then the expansive concrete is poured through the open upper end of the pouring mold 11. After the expansive concrete starts to set in 4 to 6 hours, the pouring mold 11 is removed, and the restricted expansion rate during the solidification and subsequent service process of the expansive concrete is detected in real time by collecting the output signals of the signal wires 9.

[0027] Normally, the left end plate 1 and the right end plate 2 are squares with equal sides, and the four limiting steel bars 3 are fixedly connected to the inner sides of the left end plate 1 and the right end plate 2 by welding. The welding points 7 between the four limiting steel bars and the left end plate 1 or the right end plate 2 are located at the vertices of the square with the center of the left end plate 1 or the right end plate 2 as the midpoint, which is conducive to ensuring that the four limiting steel bars 3 are evenly stressed.

[0028] As specific dimensions, the left end plate 1 and the right end plate 2 are made of steel plates with a side length of 17.7 cm and a thickness of 1.5 cm, and the diameter of the circular hole 6 of the wire tube is 1 cm. The limiting steel bar 3 shown is made of HRB335 hot-rolled ribbed steel bar with a diameter of 10 mm, and the threading tube 5 is made of a plastic tube with an outer diameter of 1 cm. The distance between the inner wall of the left end plate 1 and the inner wall of the right end plate 2 is 53.10 cm, so that the length-to-width ratio of the poured expansive concrete is 3:1, which meets the measurement specifications. A paraffin layer is applied between the inner wall of the threading tube 5 and the circular hole 6 of the wire tube to prevent the expansive concrete slurry from overflowing from the gap between the threading tube 5 and the circular hole 6 of the wire tube.

Claims

1. A device for measuring the limited expansion rate of expansive concrete, comprising a left end plate (1) and a right end plate (2) arranged parallel to each other, wherein the space between the left end plate and the right end plate is used for pouring the expansive concrete to be tested; characterized in that: The inner side of the left end plate is fixedly connected to the inner side of the right end plate via four evenly distributed limiting steel bars (3), and a strain sensor (4) for detecting the expansion and contraction amount of the limiting steel bars is arranged on the limiting steel bars. A wire tube circular hole (6) is opened in the middle of the left end plate and the right end plate, and a wire threading tube (5) is inserted into the wire tube circular hole. The internal cavity of the wire threading tube forms a wire outlet cavity (10), and a wire entry hole (8) is opened in the middle of the wire threading tube for inserting a signal line (9) of the strain sensor; the signal line of the strain sensor is inserted into the wire outlet cavity through the wire entry hole and is led out.

2. The device for measuring the limited expansion rate of expansive concrete according to claim 1, characterized in that: The four limiting steel bars (3) are fixedly connected to the inner sides of the left end plate (1) and the right end plate (2) by welding, and the welding points (7) between the four limiting steel bars and the left end plate or the right end plate are located at the vertices of a square with the center of the left end plate or the right end plate as the midpoint.

3. The device for measuring the limited expansion rate of expansive concrete according to claim 1 or 2, characterized in that: The invention comprises a casting mould (11) for assisting in casting expansive concrete between a left end plate (1) and a right end plate (2), the casting mould comprising a bottom plate (12) and two side plates (13) fixed to two sides of the bottom plate, a casting cavity (14) being formed between the bottom plate and the two side plates, the cross-sectional shape of the casting cavity being consistent with that of the left end plate (1) and the right end plate (2), and inwardly folded limiting plates (15) for limiting the positions of the left end plate and the right end plate respectively being provided at both ends of the two side plates.

4. The device for measuring the limited expansion rate of expansive concrete according to claim 1 or 2, characterized in that: The left end plate (1) and the right end plate (2) are squares with equal sides. The left end plate and the right end plate are made of steel plates with a side length of 17.7 cm and a thickness of 1.5 cm. The diameter of the circular hole (6) of the wire tube is 1 cm.

5. The device for measuring the limited expansion rate of expansive concrete according to claim 1 or 2, characterized in that: The limiting steel bar (3) is made of HRB335 hot-rolled ribbed steel bar with a diameter of 10 mm, and the threading tube (5) is made of a plastic tube with an outer diameter of 1 cm.

6. The device for measuring the limited expansion rate of expansive concrete according to claim 1 or 2, characterized in that: The distance between the inner wall of the left end plate (1) and the inner wall of the right end plate (2) is 53.10 cm.

7. The device for measuring the limited expansion rate of expansive concrete according to claim 1 or 2, characterized in that: A paraffin layer is applied between the wire threading tube (5) and the inner wall of the wire tube circular hole (6) to prevent the expansion concrete slurry from bubbling out.

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