Concrete formwork and construction method

Abstract

To provide a concrete formwork and a construction method that have less restrictions on installation positions of a temperature sensor and can also reduce construction costs.SOLUTION: A concrete formwork 100 comprises a sheathing plate 101, an RFID tag 1 that can be attached to an inner surface 101a of the sheathing plate 101, and a reader 2 separate from the RFID tag 1. In the RFID tag 1, a base film attached to the inner surface 101a, an antenna for the RFID tag that transmits temperature information indicating the temperature of concrete C by radio signal, and an IC chip that comprises a temperature sensor and a control unit are formed overlapping each other in plan view. The reader 2 receives the radio signal transmitted from the antenna for the RFID tag and acquires the temperature information. The antenna for the RFID tag has a smaller area than that of the base film in plan view. The IC chip has a smaller area than that of the antenna for the RFID tag in plan view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a concrete formwork and a construction method. [Background technology]

[0002] To construct a concrete structure, concrete is poured into the formwork, a curing period is allowed for the concrete to harden, and then the formwork is removed. The time to remove the formwork is determined, for example, based on the temperature history of the concrete. The temperature of the concrete is measured by a temperature sensor provided in the formwork. The temperature sensor is, for example, attached to a through-hole formed in the formwork (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6664810 [Patent Document 2] Patent No. 6050046 [Patent Document 3] Patent No. 5188647 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the formwork needs to have a through hole for mounting the temperature sensor, there are cases where the installation position of the temperature sensor is restricted, and since the formwork needs to have a through hole, there are cases where the construction cost is increased.

[0005] An object of one aspect of the present invention is to provide a concrete formwork and a construction method that have few restrictions on the installation position of a temperature sensor and that can reduce construction costs. [Means for solving the problem]

[0006] One aspect of the present invention provides a formwork for concrete into which concrete is poured, comprising: a sheathing; an RFID tag that can be attached to the inner surface of the sheathing; and a reader separate from the RFID tag, wherein the RFID tag comprises a temperature sensor that detects the temperature of the concrete and an antenna that transmits temperature information indicating the temperature of the concrete detected by the temperature sensor via a wireless signal, and the reader receives the wireless signal transmitted from the antenna to obtain the temperature information.

[0007] The reader preferably includes a display unit that displays the strength of the radio signal transmitted to or received from the RFID tag.

[0008] Preferably, the reader obtains the temperature information periodically.

[0009] The reader may include a main body that receives a radio signal transmitted from the antenna, and a terminal that is separate from the main body and has the display.

[0010] Another aspect of the present invention provides a construction method using a concrete formwork having a sheathing, comprising the steps of attaching an RFID tag to the inner surface of the sheathing, the RFID tag having a temperature sensor that detects the temperature of the concrete and an antenna that transmits temperature information indicating the temperature of the concrete detected by the temperature sensor by wireless signal; pouring the concrete into the internal space of the concrete formwork so that it is in contact with the RFID tag; and disposing a reader separate from the RFID tag outside the concrete formwork, and using the reader to receive the wireless signal transmitted from the antenna and obtain the temperature information. Effect of the Invention

[0011] According to one aspect of the present invention, it is possible to provide a concrete formwork and a construction method that have fewer restrictions on the installation position of a temperature sensor and that can reduce construction costs. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a concrete formwork according to a first embodiment. [Diagram 2] 1A is a plan view of a concrete formwork according to a first embodiment, and FIG.1B is a side view of the concrete formwork according to the first embodiment. [Diagram 3] 1A is a plan view of an RFID tag, and FIG. 1B is a side cross-sectional view of an RFID tag. [Figure 4] FIG. 1 is a diagram showing an outline of an RFID tag. [Diagram 5] FIG. 2 is an explanatory diagram of a method of using the concrete formwork according to the first embodiment. [Figure 6] FIG. 13 is an explanatory diagram of the method of use following the previous figure. [Figure 7] 1A is a plan view of a concrete formwork according to a second embodiment, and FIG.1B is a side cross-sectional view of the concrete formwork according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Concrete formwork] (First embodiment) FIG. 1 is a perspective view showing a concrete formwork 100 according to a first embodiment. A concrete formwork may simply be called a "formwork." FIG. 2(A) is a plan view of formwork 100. FIG. 2(B) is a side view of formwork 100. FIG. 3(A) is a plan view of an RFID tag 1. FIG. 3(B) is a side cross-sectional view of RFID tag 1. FIG. 3(B) is a cross-sectional view taken along line II of FIG. 3(A). FIG. 4 is a schematic diagram showing the configuration of RFID tag 1.

[0014] As shown in Fig. 1, a formwork 100 includes a sheathing board 101, an RFID (Radio Frequency Identification) tag 1, and a reader 2. The RFID tag 1 and the reader 2 constitute a "concrete curing management device 10."

[0015] The space on the inner surface 101a side of the sheathing 101 is an internal space 102 into which concrete C is poured. The surface of the sheathing 101 opposite the inner surface 101a is referred to as an outer surface 101b. The sheathing 101 is made of an insulating material such as wood material or resin. The sheathing 101 is made of, for example, plywood.

[0016] 2(B), the RFID tag 1 is attached to the inner surface 101a of the sheathing 101. The RFID tag 1 is formed in a sheet shape. The RFID tag 1 is installed with the back surface 11b facing the inner surface 101a. The thickness of the RFID tag 1 may be, for example, 200 μm to 1000 μm.

[0017] 3(A) and 3(B), the RFID tag 1 is configured by laminating, in this order, a base film 11, an antenna 12, an RFID IC chip 13, and a waterproof film 14. The RFID tag 1 is a non-contact data transmitter / receiver capable of transmitting and receiving information to and from the outside by wireless communication using radio waves as a medium.

[0018] 3(B), the base film 11 is made of an insulating material such as a resin. Examples of the resin that makes up the base film 11 include polyethylene terephthalate (PET) and polyimide. The back surface 11b of the base film 11 is attached to the inner surface 101a of the sheathing board 101 by an adhesive layer 15. The adhesive layer 15 is made of, for example, a double-sided adhesive tape, an adhesive, or the like.

[0019] The antenna 12 is formed of a metal layer formed on the front surface 11a of the base film 11. The metal layer is formed of, for example, a plating layer made of copper, aluminum, or the like, or a metal foil. The antenna 12 is formed by processing the metal layer into a predetermined shape by etching or the like. The antenna 12 transmits the temperature information of the concrete C by wireless signal based on the instruction signal from the RFID IC chip 13. The temperature information of the concrete C is information that indicates the temperature of the concrete C.

[0020] As shown in Fig. 4, the RFID IC chip 13 is an RFID IC chip with a built-in temperature sensor. In more detail, the RFID IC chip 13 includes, for example, a temperature sensor 16 and a control unit 17. The RFID IC chip 13 may include a memory, a power supply circuit, and the like. The RFID IC chip 13 is formed in a plate shape (see Fig. 3(B)). The RFID IC chip 13 is placed in a position parallel to the base film 11.

[0021] Examples of the temperature sensor 16 include a resistance temperature detector, a thermocouple, and a thermistor. The temperature sensor 16 detects the temperature of the concrete C. The control unit 17 acquires temperature information of the concrete C as digital information. The control unit 17 sends an instruction signal to the antenna 12 based on the detection result of the temperature sensor 16. The RFID IC chip 13 is electrically connected to the antenna 12 via a lead wire 19 or a terminal of the IC chip.

[0022] As shown in Fig. 3(B), the waterproof film 14 is a waterproof film made of resin or the like. The waterproof film 14 covers the antenna 12 and the RFID IC chip 13. The waterproof film 14 is adhered to the base film 11 at an adhesive portion surrounding the antenna 12 and the RFID IC chip 13 when viewed in the thickness direction. In this way, the waterproof film 14 seals the antenna 12 and the RFID IC chip 13. The waterproof film 14 prevents water from entering from the outside and protects the antenna 12 and the RFID IC chip 13.

[0023] The RFID tag 1 is a laminate of a base film 11, a layered antenna 12, a plate-shaped RFID IC chip 13, and a waterproof film 14, and is thus in a sheet shape as a whole. Note that the RFID tag 1 is not limited to being in a sheet shape, and may also be in a plate shape (for example, a plate shape having a thickness of more than 1000 μm).

[0024] As shown in Fig. 1, the reader 2 receives a radio signal transmitted from an antenna 12 (see Fig. 3(B)) of the RFID tag 1 to acquire temperature information of the concrete C. The reader 2 can acquire the temperature information without contacting the RFID tag 1. The reader 2 is separate from the RFID tag 1.

[0025] As shown in FIG. 2(A), the reader 2 includes a main unit 21 and a display unit 22. The main unit 21 includes an antenna 23 , a control unit 24 , and a storage unit 25 .

[0026] The antenna 23 receives the radio signal transmitted from the RFID tag 1, and transmits the data to the control unit 24. As a result, the control unit 24 obtains the temperature information of the concrete C as digital information. The storage unit 25 is, for example, a flash memory, a HDD, or the like.

[0027] The display unit 22 includes a display 31 and an indicator light 32 . The display 31 is, for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, etc. The display 31 can display data on radio wave strength, which will be described later. For example, in Fig. 1 and Fig. 2(A), "-36 dBm" is displayed as the radio wave strength.

[0028] The indicator light 32 is, for example, an LED element. When the radio wave strength reaches or exceeds a predetermined reference value, the indicator light 32 can visibly indicate this. For example, the indicator light 32 can turn on a red light when the radio wave strength falls below the reference value, and turn on a green light when the radio wave strength reaches or exceeds the reference value. Therefore, when the indicator light 32 turns on with a green light, it can be confirmed that the radio wave strength reaches or exceeds the reference value.

[0029] The main unit 21 and the display unit 22 are housed in a housing 26. The housing 26 is formed in a rectangular parallelepiped shape, for example, in the shape of a thick plate case. A back surface 26a of the housing 26 is the surface opposite to the surface on which the display 31 is provided.

[0030] [Construction method] (First embodiment) An example of a construction method using the formwork 100 shown in FIG. 1 will be described.

[0031] (1st step: Attaching RFID tags) 3(B), the RFID tag 1 is attached to the inner surface 101a of the sheathing 101 using an adhesive layer 15 (e.g., double-sided adhesive tape). As a result, the RFID tag 1 is attached to the inner surface 101a of the sheathing 101 with the back surface 11b of the base film 11 facing the inner surface 101a. The antenna 12 of the RFID tag 1 is parallel to the inner surface 101a. The RFID tag 1 is installed at a height where it is buried in the concrete C poured into the formwork 100 .

[0032] (Second step: pouring concrete) 1, concrete C is poured into an internal space 102 of a formwork 100. The RFID tag 1 is embedded in the concrete C. As a result, the concrete C is in contact with the RFID tag 1 in a manner that allows heat transfer.

[0033] (Step 3: Check the signal strength) The reader 2 is placed outside the formwork 100. The reader 2 is preferably placed in contact with the outer surface 101b of the sheathing 101. The reader 2 is oriented such that the back surface 26a of the housing 26 faces the outer surface 101b.

[0034] The control unit 24 of the reader 2 operates the antenna 23 (see FIG. 2(A)), and the antenna 23 transmits a confirmation signal (radio signal) by wireless communication to the RFID tag 1. A part of the confirmation signal passes through the sheathing 101 from the outer surface 101b to the inner surface 101a.

[0035] The antenna 12 of the RFID tag 1 receives the confirmation signal (wireless signal) and transmits a detection signal to the control unit 17 (see FIG. 4). The control unit 17 acquires, as digital information, data on the strength (radio wave intensity) of the radio signal when the antenna 12 receives the confirmation signal (radio wave signal) transmitted from the reader 2. The radio wave intensity is, for example, RSSI (Received Signal Strength Indication).

[0036] The radio wave strength is affected by the state of the radio waves transmitted and received between the RFID tag 1 and the reader 2. The radio wave strength is a value that depends on, for example, the distance between the RFID tag 1 and the reader 2 and the surrounding radio wave conditions.

[0037] The control unit 17 sends an instruction signal to the antenna 12 (see FIG. 4). Based on the instruction signal, the antenna 12 transmits the above-mentioned radio wave intensity data as a wireless signal. A part of the wireless signal passes through the sheathing 101 from the inner surface 101a to the outer surface 101b.

[0038] As shown in FIG. 2A, the antenna 23 of the reader 2 receives the radio signal transmitted from the RFID tag 1, and transmits the above-mentioned radio field intensity data to the control unit 24. As shown in FIG. 5, the control unit 24 displays the data of the radio wave intensity sent from the RFID tag 1 on the display 31.

[0039] The indicator light 32 is set to, for example, light red when the radio wave strength falls below a reference value, and light green when the radio wave strength exceeds the reference value. In Fig. 5, the radio wave strength of the reader 2 is below the reference value (e.g., -36 dBm). Therefore, the indicator light 32 lights red.

[0040] While checking the radio wave intensity displayed on the display 31, the reader 2 is moved along the outer surface 101b of the sheathing 101 as necessary (see the arrow in FIG. 5). As described above, the radio wave intensity is a value that depends on the distance between the RFID tag 1 and the reader 2, the surrounding radio wave conditions, etc. For example, if the reader 2 is placed in a position where the antenna 23 (see FIG. 2(A)) faces the antenna 12 (see FIG. 3(A)) of the RFID tag 1, the distance between the antenna 23 and the antenna 12 becomes small. This results in good radio wave conditions, and there is a possibility that the radio wave intensity will increase.

[0041] As shown in Fig. 6, the reader 2 is placed in a position where the radio wave intensity is equal to or greater than the reference value. In Fig. 6, the radio wave intensity acquired by the reader 2 is equal to or greater than the reference value (e.g., -18 dBm), and the indicator light 32 is lit in green.

[0042] The reader 2 is fixed to the outer surface 101b of the sheathing 101 at a position where the radio wave intensity is equal to or greater than a reference value. The reader 2 can be fixed to the outer surface 101b with double-sided adhesive tape, adhesive, or the like.

[0043] (4th step: Acquiring temperature information of concrete) The control unit 24 of the reader 2 operates the antenna 23 (see FIG. 2(A)), and the antenna 23 transmits a request signal via wireless communication to the RFID tag 1. A part of the request signal passes through the sheathing 101 from the outer surface 101b to the inner surface 101a. The antenna 12 of the RFID tag 1 receives the request signal and transmits a detection signal to the control unit 17 (see FIG. 4).

[0044] As shown in Fig. 4, the temperature sensor 16 of the RFID tag 1 detects the temperature of the concrete C and transmits the detection result to the control unit 17. Based on the detection result, the control unit 17 sends an instruction signal to the antenna 12. Based on the instruction signal, the antenna 12 transmits temperature information of the concrete C by wireless signal. Part of the wireless signal passes through the sheathing 101 from the inner surface 101a to the outer surface 101b (see Fig. 1).

[0045] 2(A), the antenna 23 of the reader 2 receives the wireless signal transmitted from the RFID tag 1 and transmits the data to the control unit 24. As a result, the control unit 24 acquires temperature information of the concrete C as digital information. The acquired temperature information is recorded in the memory unit 25.

[0046] The reader 2 can repeatedly acquire temperature information multiple times at predetermined time intervals. The acquisition of temperature information may be performed periodically at regular time intervals. The time interval for acquiring temperature information is not particularly limited. By acquiring temperature information multiple times over time, the temperature history of the concrete C can be ascertained. The temperature history of the concrete C can be used for curing management of the concrete C.

[0047] (5th step: Removing the formwork) The hardened state of the concrete C can be determined based on the temperature history of the concrete C. The time to remove the formwork 100 is determined based on the determination result, and the formwork 100 is removed from the hardened concrete C. In this way, a concrete structure is obtained.

[0048] [Effects of the formwork and construction method of the first embodiment] Since the formwork 100 does not require the formation of an insertion hole, there are fewer restrictions on the installation position of the RFID tag 1 compared to a formwork in which a temperature sensor is attached to the insertion hole of the formwork. This allows for greater freedom in designing the type and design of the concrete structure.

[0049] Since the formwork 100 uses an RFID tag 1 that can be attached to the inner surface 101a of the sheathing 101, no processing (drilling) is required, unlike the case of using a temperature sensor that is attached to an insertion hole in the formwork. This makes it possible to keep construction costs low. Since the formwork 100 does not require the formation of an insertion hole, the sheathing 101 can be reused after use (for example, for use in another formwork). This makes it possible to keep construction costs low. The formwork 100 is also excellent in terms of ease of construction, since the RFID tag 1 can be easily installed.

[0050] Since the RFID tag 1 is in sheet form in the formwork 100, the RFID tag 1 is unlikely to leave a trace (depression) on the concrete structure. Even if the RFID tag 1 leaves a trace (depression), the trace (depression) is shallow and not very noticeable. This is therefore suitable in terms of ensuring the aesthetic appearance of the concrete structure. Since the RFID tag 1 is unlikely to leave a trace on the concrete structure, it is also advantageous in terms of preventing a decrease in the strength of the concrete structure and ensuring its functionality.

[0051] Since the RFID tag 1 is in a sheet shape, the protrusion dimension from the inner surface 101a of the sheathing 101 is small. Therefore, the force applied to the RFID tag 1 by the concrete C when pouring is smaller than that of an RFID tag that protrudes significantly from the inner surface 101a. Therefore, the RFID tag 1 is less likely to move or fall off. This enables stable wireless communication between the RFID tag 1 and the reader 2.

[0052] The reader 2 is equipped with a display unit 22 that displays the radio wave intensity. Therefore, even if the RFID tag 1 is buried in the concrete C and the position of the RFID tag 1 is difficult to confirm, the reader 2 can be placed at a position where the radio wave intensity is high. Therefore, the temperature information of the concrete C can be easily obtained.

[0053] The reader 2 periodically obtains the temperature information of the concrete C, thereby making it possible to grasp the temperature history of the concrete C. This makes it easy to manage the curing of the concrete C.

[0054] [Concrete formwork] (Second embodiment) Fig. 7(A) is a plan view of a formwork 200 according to the second embodiment. Fig. 7(B) is a side view of the formwork 200. The same reference numerals are used for the components common to the formwork 100 (see Fig. 1) of the first embodiment, and the description thereof will be omitted.

[0055] As shown in Figures 7(A) and 7(B), formwork 200 includes a sheathing board 101, an RFID tag 1, and a reader 52. Formwork 200 differs from formwork 100 of the first embodiment in that it uses reader 52 instead of reader 2. RFID tag 1 and reader 52 constitute a "concrete curing management device 50."

[0056] The reader 52 comprises a main body 53 and a terminal 54 . The main body 53 includes a main unit 21. The main unit 21 includes an antenna 23, a control unit 24, and a storage unit 25. The main unit 21 is housed in a housing 26.

[0057] The terminal 54 is separate from the main body 53. The terminal 54 includes a main unit 51 and a display unit 22. The main unit 51 includes an antenna 55 and a control unit 56. The terminal 54 can wirelessly communicate with the main body 53 by, for example, BLE communication.

[0058] [Construction method] (Second embodiment) An example of a construction method using the formwork 200 will be described below. The first and second steps are the same as those in the first embodiment, and therefore will not be described.

[0059] (Step 3: Check the signal strength) The reader 2 transmits a confirmation signal (radio signal) via wireless communication to the RFID tag 1. The RFID tag 1 acquires digital information on the strength (radio field strength) of the radio signal when it receives the confirmation signal (radio signal) transmitted from the reader 2. The RFID tag 1 transmits the radio field strength data as a wireless signal.

[0060] The antenna 23 of the main body 53 receives the radio signal transmitted from the RFID tag 1, and transmits the above-mentioned data on the radio wave intensity to the control unit 24. The antenna 23 transmits the data on the radio wave intensity by radio signal in accordance with an instruction signal from the control unit 24.

[0061] The antenna 55 of the terminal 54 receives the wireless signal transmitted from the main body 53 and transmits it to the control unit 56. As a result, the control unit 56 obtains data on the radio wave intensity. The radio wave intensity is displayed on the display 31 of the terminal 54.

[0062] While checking the radio wave intensity displayed on the display 31, move the main body 53 along the outer surface 101b of the sheathing 101 as necessary. Place the main body 53 in a position where the radio wave intensity is equal to or greater than the reference value. Fix the main body 53 to the outer surface 101b of the sheathing 101 at the position where the radio wave intensity is equal to or greater than the reference value.

[0063] (4th step: Acquiring temperature information of concrete) The temperature sensor 16 of the RFID tag 1 detects the temperature of the concrete C and transmits the detection result to the control unit 17. Based on the detection result, the control unit 17 sends an instruction signal to the antenna 12. Based on the instruction signal, the antenna 12 transmits temperature information of the concrete C by wireless signal (see FIG. 4).

[0064] The antenna 23 of the main body 53 receives the wireless signal transmitted from the RFID tag 1, and the control unit 24 acquires the temperature information of the concrete C. The acquired temperature information is recorded in the storage unit 25. The reader 52 can repeatedly obtain temperature information multiple times at predetermined time intervals, thereby making it possible to grasp the temperature history of the concrete C.

[0065] (5th step: Removing the formwork) The time to remove the formwork 200 is determined based on the temperature history of the concrete C, and the formwork 200 is removed from the hardened concrete C. In this way, a concrete structure is obtained.

[0066] [Effects of the formwork and construction method of the second embodiment] The formwork 200 includes a terminal 54 that is separate from the main body 53. Since the antenna 23, the control unit 24, the storage unit 25, etc. are provided in the main body 53, the terminal 54 having the display unit 22 can be made small and portable. Thus, the formwork 200 is excellent in terms of ease of handling of the device.

[0067] Like the formwork 100 of the first embodiment, the formwork 200 does not require the formation of an insertion hole, and therefore there are fewer restrictions on the installation position of the RFID tag 1. This allows for a high degree of freedom in designing the type and design of the concrete structure. The formwork 200 does not require any processing (hole drilling). In addition, the sheathing 101 can be reused. Therefore, construction costs can be kept low. The formwork 200 is also excellent in terms of ease of construction.

[0068] Since the RFID tag 1 is in a sheet form in the formwork 200, the RFID tag 1 is unlikely to leave a mark (a recess) in the concrete structure, which is preferable in terms of ensuring the aesthetic appearance of the concrete structure. Since the reader 52 is equipped with the display unit 22 that displays the radio wave intensity, the reader 52 can be placed in a position where the radio wave intensity is high. Therefore, the temperature information of the concrete C can be easily obtained. When the reader 52 periodically acquires temperature information of the concrete C, curing management of the concrete C becomes easier.

[0069] Although the embodiments of the present invention have been described above, each configuration and their combinations in the embodiments are merely examples, and addition, omission, substitution, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments. For example, the number of RFID tags 1 installed in the formwork 100 is not limited to one, and may be multiple (any number equal to or greater than two). For example, multiple RFID tags 1 can be installed on the inner surface 101a of the sheathing 101 at different positions in the width direction, length direction, height direction, etc. of the sheathing 101. By using multiple RFID tags 1, it is possible to obtain temperature information for multiple locations on the concrete C. This makes it possible to realize highly accurate curing management.

[0070] Since the reader 2 is separate from the RFID tag 1, when multiple RFID tags 1 are used, one reader 2 can be used to collect temperature information from the multiple RFID tags 1. This allows the number of readers 2 used to be reduced, leading to cost savings.

[0071] In the above embodiment, the indicator light 32 is set to turn on a red light when the radio wave strength falls below a reference value and to turn on a green light when the radio wave strength is equal to or greater than the reference value, but the configuration of the indicator light 32 is not particularly limited. The indicator light 32 only needs to be able to visually indicate that the radio wave strength is equal to or greater than the reference value. For example, the indicator light 32 may be configured to turn off when the radio wave strength falls below the reference value and turn on when the radio wave strength is equal to or greater than the reference value.

[0072] In the above-described embodiment, the display unit 22 of the reader 2 displays the strength of the radio signal sent from the reader 2 to the RFID tag 1, but the configuration of the display unit 22 is not limited to this. The display unit 22 may also display the strength of the radio signal sent from the RFID tag 1 to the reader 2. In other words, the display unit 22 may display the strength of the radio signal transmitted or received between the reader 2 and the RFID tag 1.

[0073] As long as the RFID tag 1 is in contact with the concrete C poured into the formwork 100 in a heat-transferable manner, it does not have to be embedded in the concrete C. However, in order to obtain highly accurate temperature information, it is preferable that the RFID tag 1 be embedded in the concrete C.

[0074] The reader 2 can check the radio wave intensity and obtain the temperature information without abutting it against the outer surface 101b of the sheathing 101. However, in order to check the radio wave intensity and obtain the temperature information with high accuracy, it is preferable to abut the reader 2 against the outer surface 101b of the sheathing 101. In the formwork 100, the reader 2 is provided with a display unit 22, but the formwork of the embodiment may use a reader that does not have a display unit. [Explanation of symbols]

[0075] 1...RFID tag, 2,52...reader, 12...antenna, 16...temperature sensor, 22...display unit, 53...main body, 54...terminal, 100,200...formwork (formwork for concrete), 101...shield, 101a...inner surface, 102...internal space, C...concrete.

Claims

1. A concrete formwork into which concrete is poured, The decking and an RFID tag attachable to an inner surface of the sheathing; A reader separate from the RFID tag; Equipped with The RFID tag comprises: A base film attached to the inner surface; an RFID tag antenna that transmits temperature information indicating the temperature of the concrete by wireless signal; an IC chip including a temperature sensor that detects the temperature of the concrete and an RFID tag control unit that acquires the temperature information; are formed in a plan view so as to overlap each other, the RFID tag control unit sends an instruction signal to the RFID tag antenna based on the detection result of the temperature sensor; the RFID tag antenna transmits the temperature information by a wireless signal based on the instruction signal; The reader receives the radio signal transmitted from the RFID tag antenna to obtain the temperature information; the RFID tag antenna has an area smaller than that of the base film in a plan view; the IC chip has an area smaller than that of the RFID tag antenna in a plan view; Formwork for concrete.

2. A concrete formwork into which concrete is poured, The decking and an RFID tag attachable to an inner surface of the sheathing; A reader separate from the RFID tag; Equipped with The RFID tag comprises: A base film attached to the inner surface; an RFID tag antenna that transmits temperature information indicating the temperature of the concrete by wireless signal; an IC chip including a temperature sensor that detects the temperature of the concrete and an RFID tag control unit that acquires the temperature information; are formed in a plan view so as to overlap each other, the reader includes a reader antenna that receives the radio signal transmitted from the RFID tag antenna, and a reader control unit that acquires the temperature information obtained from the reader antenna; The reader control unit causes the reader antenna to transmit a request signal, the RFID tag antenna receives the request signal and transmits a detection signal to the RFID tag control unit; The RFID tag control unit acquires the temperature information from the temperature sensor, the RFID tag antenna has an area smaller than that of the base film in a plan view; the IC chip has an area smaller than that of the RFID tag antenna in a plan view; Formwork for concrete.

3. the RFID tag further includes a waterproof film that covers the RFID tag antenna and the IC chip and is adhered to the base film; The waterproof film is a tilt angle that approaches the RFID tag antenna as it moves away from the IC chip within a range from the IC chip to the RFID tag antenna; the inclination is such that the distance from the RFID tag antenna increases and the distance approaches the base film, within a range from the RFID tag antenna to the base film; 3. A concrete formwork according to claim 1 or 2.

4. the reader includes a reader antenna that receives the radio signal transmitted from the RFID tag antenna, a reader control unit that acquires the temperature information obtained from the reader antenna, and a display unit that displays the strength of the radio signal transmitted to or received from the RFID tag; The reader control unit causes the reader antenna to transmit a confirmation signal, the RFID tag antenna receives the confirmation signal and transmits a detection signal to the RFID tag control unit; the RFID tag control unit causes the RFID tag antenna to transmit data on radio wave intensity when the RFID tag antenna receives the confirmation signal, The reader antenna receives the data of the radio wave intensity and transmits it to the reader control unit; the display unit includes an indicator light that visibly indicates that the radio wave strength is equal to or greater than a reference value when the radio wave strength is equal to or greater than a reference value.

2. The concrete formwork according to claim 1.

5. The concrete formwork according to any one of claims 1 to 3, wherein the reader is provided with a display unit that displays the strength of the radio signal transmitted to or received from the RFID tag.

6. The concrete formwork according to any one of claims 1 to 5, wherein the reader periodically obtains the temperature information.

7. The reader includes: a main body for receiving a radio signal transmitted from the RFID tag antenna; A terminal separate from the main body and having the display unit; The concrete formwork according to claim 4 or 5, comprising:

8. The RFID tag further includes a waterproof film that covers the RFID tag antenna and the IC chip and is adhered to the base film.

3. A concrete formwork according to claim 1 or 2.

9. the display unit includes an indicator light that visibly indicates that the strength of the wireless signal has reached or exceeded a reference value when the strength of the wireless signal has reached or exceeded a reference value. A concrete formwork according to claim 5.

10. The base film is attached to the inner surface by an adhesive layer. A concrete formwork according to any one of claims 1 to 9.

11. A construction method using a concrete formwork having a sheathing, comprising: a step of attaching an RFID tag to the inner surface of the sheathing, the RFID tag being formed by overlapping in a plan view a base film to be attached to the inner surface of the concrete formwork, an RFID tag antenna that transmits temperature information indicating the temperature of the concrete by wireless signal, and an IC chip that includes a temperature sensor that detects the temperature of the concrete and an RFID tag control unit that acquires the temperature information; pouring the concrete into the internal space of the concrete formwork so as to be in contact with the RFID tag; a step of disposing a reader separate from the RFID tag outside the concrete formwork, and receiving a radio signal transmitted from the RFID tag antenna by the reader to obtain the temperature information; having the RFID tag control unit sends an instruction signal to the RFID tag antenna based on the detection result of the temperature sensor; the RFID tag antenna transmits the temperature information by the wireless signal based on the instruction signal; the RFID tag antenna has an area smaller than that of the base film in a plan view; the IC chip has an area smaller than that of the RFID tag antenna in a plan view; Construction method.

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