JP4152837B2 - Grouting material filling status detection device, detector and sheath tube used therefor, and grout filling status confirmation method - Google Patents

Description

  The present invention relates to an apparatus for detecting a state of filling a grout material in a grout construction of a prestressed concrete structure by a sensor unit attached to a sheath tube.

  Prestressed concrete is a steel material that can withstand high tension and gives compressive stress to the concrete, which has significantly improved bending strength compared to conventional reinforced concrete, and is suitable for bridges, building structures, various tanks, disaster prevention equipment, etc. It's being used.

  The prestressed concrete can be produced by applying a tension to the steel material in advance and placing the concrete in advance. After the concrete has hardened, the tension is released and compressive stress is introduced into the concrete. There is a post-tension system in which concrete is placed after the sheath pipe is placed, and the steel material passed through the sheath pipe is tensioned after the concrete is hardened to introduce compressive stress into the concrete.

  In the post-stressed prestressed concrete, the grout material is filled in the sheath tube for the purpose of integrating the steel material with the concrete and for preventing the steel material from being damaged by corrosion or the like. However, if there is an unfilled portion of the grout material in the sheath tube, chloride ions will enter the case of water and oxygen, as well as the case of structures near the coast and the case where antifreeze is used, and the steel material will corrode for a long period of time. The load-bearing performance of prestressed concrete may be greatly reduced. Therefore, in this construction method, it is necessary to distribute the grout material throughout the sheath tube.

  Conventionally, as a method for confirming the filling of the grout material, it has been estimated from a method of directly confirming the discharge of the grout material from the air discharge port installed on the opposite side of the grout material inlet, and a void ratio in the sheath tube. There are a method for estimating the filling rate from a comparison between the amount of voids to be injected and the amount of grout material actually injected, and a method for visually checking the filling by providing inspection holes. Among them, the non-destructive inspection methods include a method in which an elastic wave is incident and a reflected wave is received and detected, a method in which an unfilled portion of a grout material is detected by an X-ray transmission method, and an ultrasonic wave is input to reflect the reflected wave. There are a method for detecting neutrons, a method for detecting absorption of neutrons, and the like (for example, Patent Documents 1 and 2).

As a method using a sensor, there is a method of checking the filling of a grout material by embedding a sensor connected to a conductive cord extending to the outside of concrete (for example, Patent Document 3). In addition, there is a method of reading information sensed by a sensor externally without using cordless communication technology (for example, Patent Document 4 and Patent Document 5). This method is a method in which internal information of a structure is sensed by a sensor embedded therein, the sensed information is read by a reading device by wireless communication, and an internal state is measured.
JP-A-10-54140 JP 2001-241187 A JP-A-10-231520 JP 2001-201373 A JP2003-107030

  As described above, various methods have been proposed to detect the internal state of concrete. However, any of the methods of detecting the inside of concrete using elastic waves, ultrasonic waves, X-rays or neutrons has low accuracy and it is difficult to determine whether the grout material is filled or not. Moreover, these methods are complicated.

  Also, in the method of extending the conductive cord from the sensor embedded inside to the outside of the concrete, the conductive cord or the contact surface between the conductive cord and the concrete can be a path for corrosion factors of steel materials such as oxygen, water or chloride ions. There is sex. In particular, when a concrete structure is used over a long period of time, a large difference in the durability of the concrete can occur.

  Also, a method for measuring the internal state of a structure with a reader by wireless means is known, but a specific method for detecting the filling of a grout material into a sheath tube is proposed for grouting a prestressed concrete structure. It has not been.

  The present invention senses the state of filling of the sheath tube with the grout material in the grout construction of the prestressed concrete structure by the sensor attached to the sheath tube, and fills the grout material with the reader that reads the sensed information by the wireless communication means. It is an object of the present invention to provide a situation detection device, a sheath tube to which detectors and sensors necessary for the situation detection device are attached, and a grout filling method using the sheath tube.

  (1) In order to achieve the above object, the grout filling state detection device of the present invention is a device that detects the filling state of the grout material filled in the sheath tube in the grout construction with the prestressed concrete structure. And an embedded sensor unit for sensing the presence or absence of filling of the grout material and a reading device, and data transmission from the sensor unit to the reading device is performed by wireless communication.

  As described above, in the present invention, the grout filling state is confirmed by wireless communication between the embedded sensor unit and the reader when grouting is performed. Thereby, even if the sheath tube is arranged at a deep position from the concrete surface, it is possible to know the filling state of the grout material easily without destruction. In addition, it is possible to easily check whether or not the grout material is filled without using wiring from the outside of the concrete structure. As a result, a durable structure can be constructed without corrosive factors that impair the durability of the concrete structure entering through the wiring.

  (2) Moreover, the detector of the present invention is a detector used in the sensor unit of the grout filling state detection device described above, and includes a built-in sensor or an external sensor for sensing the presence or absence of the grout material, an antenna, And a modulation device and a protective case.

  Accordingly, the detector can be provided with a function of sensing information, performing a certain process inside, and transmitting the information together with the sensor identification information. As a result, it is possible to easily confirm whether or not the grout material is filled from the outside of the concrete structure.

  (3) The sheath tube of the present invention is a sheath tube used for grouting in a prestressed concrete structure, and is filled in the sheath tube that is in contact with or attached to the sheath tube. It is characterized in that one or a plurality of external sensors or sensor portions for detecting the presence or absence of filling of grout material are provided at intervals in the length direction.

  Thus, in this invention, after manufacturing the sheath pipe | tube which attached the sensor part so that the filling condition of grout material can be detected previously, it is carried to the spot which constructs a concrete structure, and is embed | buried. Thereby, a sensor part can be suitably arrange | positioned in the position which wants to know the filling condition of the grout material of a sheath pipe | tube by the design of a structure, or the condition of a construction site. In addition, attaching the sensor unit at the site is complicated from the viewpoint of equipment, personnel, and the like. However, by attaching the sensor unit to the sheath tube in advance, the complexity of such field work can be eliminated. Further, since the sensor unit transmits information by wireless communication, the sensor unit can be arranged without any particular limitation.

  (4) Moreover, the grout filling state confirmation method of the present invention is a grout for a sheath tube using a grout filling state detection device including a sensor unit and a reader in grout construction with a pressrest concrete structure. A method for confirming a filling state of a material, wherein the presence or absence of filling of a grout material is detected by an external sensor attached to the sheath tube or in the sheath tube or by a built-in sensor of the sensor unit, and the detected information is detected by the sensor. The wireless communication device converts the signal into a radio signal and transmits the signal to the reading device by wireless communication, and confirms the filling condition of the grout material in the sheath tube from the information received by the reading device.

  As described above, in the present invention, the grout filling state is confirmed by wireless communication between the embedded sensor unit and the reader when grouting is performed. Thereby, even if the sheath tube is arranged at a deep position from the concrete surface, it is possible to know the filling state of the grout material easily without destruction. In addition, it is possible to easily check whether or not the grout material is filled without using wiring from the outside of the concrete structure. As a result, a durable structure can be constructed without corrosive factors that impair the durability of the concrete structure entering through the wiring.

  (5) Moreover, the grout filling state confirmation method of the present invention is applied to the sheath tube when the sheath tube is made of metal, or to the PC steel material inserted into the sheath tube when the sheath tube is not made of metal. In addition, an antenna function for transmitting the radio signal is provided.

  Thereby, while reducing the member required for the structure of a detector, electromagnetic waves can be radiated | emitted efficiently. In addition, the same effect can be obtained as when the antenna is provided with a cover from the concrete surface to the embedded position of the sheath tube, etc. When the sheath tube is at a deep position, information is read by wireless communication from the sensor unit. It can be easily read by the device.

  Even when the sheath tube is arranged at a deep position from the concrete surface, it is possible to easily know the filling condition of the grout material without any destruction. In addition, it is possible to easily check whether or not the grout material is filled without using wiring from the outside of the concrete structure. As a result, a durable structure can be constructed without corrosive factors that impair the durability of the concrete structure entering through the wiring.

(Embodiment 1)
Hereinafter, the grout filling state detection apparatus according to the first embodiment will be described. FIG. 1 is a perspective view of a grout filling state detection apparatus and a sheath tube according to the present invention. The grout filling state detection device 1 includes an embedded sensor unit 2 and an external reader 3. The sensor unit 2 is embedded in the concrete while being attached to the sheath tube 4. The sheath tube is a pipe-like sheath tube that is embedded in concrete by prestressed concrete construction and penetrates a PC steel material. For prestressed concrete construction, a sheath tube made of an organic resin such as polyethylene or plastic or made of metal and having a diameter of about 20 to 100 mm is often used, but the present invention is not limited to the material or form of the sheath tube. The number of sheath pipes embedded in concrete may be one, but it may be several. As shown in FIG. 1, the sheath tube 4 is provided with ribs 4a in order to improve adhesion to concrete. PC steel refers to a cable that is inserted through a sheath tube in prestressed concrete construction and is tensioned to give compressive force to the concrete. The grout material refers to a material used to fill a gap between the sheath tube and the PC steel material, and mainly refers to a mixed liquid (cement milk) in which cement and water are mixed, but a resin or the like may be used.

  The embedded position of the sensor unit is a position deeper than the concrete surface, that is, a position completely covered with concrete. Thereby, deterioration of the sensor due to corrosion factors such as oxygen, water, chloride ions, and carbon dioxide gas entering from the outside can be prevented, and the corrosion factor can be prevented from reaching the PC steel through the sensor portion. In FIG. 1, the sensor portion is provided outside the sheath tube, but the sensor portion may be provided inside, or the sensor portion may be attached on the PC steel material and inserted into the sheath tube together with the PC steel material. In this case, since the sensor portion is provided inside the sheath tube, there is no need to make a hole in the sheath tube, and the possibility that a corrosive factor enters through the gap generated by the attachment of the sheath tube and the sensor portion is reduced. The anticorrosive effect can be maintained, and the trouble of sealing this gap can be eliminated.

  FIG. 2 is a cross-sectional view of the grout filling state detecting device and sheath tube, concrete, PC steel and grout according to the present invention. A PC steel material 6 is inserted into the sheath tube 4 embedded in the concrete 5 and is strained, and a grout material 7 is injected.

  By adopting the above-described configuration, the state of filling of the grout material is confirmed by wireless communication between the embedded sensor unit and the reading device at the time of grout construction. Thereby, even if the sheath tube is arranged at a deep position from the concrete surface, it is possible to know the filling state of the grout material easily without destruction. In addition, it is possible to easily check whether or not the grout material is filled without using wiring from the outside of the concrete structure. As a result, a durable structure can be constructed without corrosive factors that impair the durability of the concrete structure entering through the wiring.

  For the sensor unit 2, a detector of a grout material having a sensor, an antenna, a modulation device, a power storage / power supply unit, and a protective case is used. FIG. 3 is a block diagram showing an electrical configuration of the sensor unit 2. As shown in FIG. 3, the sensor unit 2 includes a CPU 21, a power storage / power supply unit 22, a ROM 23, a RAM 24, a sensor 25, a sensor control unit 26, a modulation / demodulation unit 27, and an antenna 28. The CPU 21 controls the sensor unit 2 in accordance with a preset program, and performs data processing of transmission / reception signals, digital conversion of analog information sensed by the sensor, power supply control, and other data processing. For example, an analog signal sensed by the sensor is converted into a digital signal and processed as a digital signal such as the presence or absence of a grout material.

  The power storage / power supply unit 22 supplies power necessary for driving each block of the CPU 21, ROM 23, RAM 24, sensor control unit 26, and modulation / demodulation unit 27 included in the sensor unit 2. The power storage / power supply unit 22 may temporarily store a dielectric voltage obtained from electromagnetic waves. In that case, the power storage / power supply unit 22 rectifies and stores the current flowing from the antenna 28 that has received the electromagnetic waves. In order to induce a dielectric voltage, the fog from the concrete surface of the sensor part is preferably within 100 mm. Since it is necessary to maintain the function of the sensor unit while it is not used during the curing period after placing the concrete, it is sufficient that the power storage / power source unit can withstand the unused state for at least several weeks to one month. In consideration of the period until concrete pouring or the period after curing after grout injection, it is desirable that the function can be maintained even when unused for several months. The antenna may be provided outside the sensor unit by extending the wiring.

  The sensor unit has a built-in memory, and the memory includes a ROM 23 and a RAM 24. The ROM 23 stores a program for determining the presence or absence of a signal detected by the sensor and transmitting the signal to the reading device, a control program for controlling the operation of the entire sensor unit, and the like. The RAM 24 records information from the outside, a record of the presence / absence of a grout material, information on the embedded position of the sensor unit, and other necessary information.

  The ROM 23 includes not only a completely read-only memory but also a so-called EEPROM (electrically erasable programmable ROM). In this case, the EEPROM stores a program for detecting data rewriting and the state of the structure. Thereby, the response | compatibility according to the design of a structure or the condition of the field can be taken. Further, an identification code unique to the sensor may be recorded in the memory.

  The sensor 25 functions as a built-in sensor or an external sensor. The built-in sensor refers to a sensor provided integrally with the sensor unit body, and the external sensor refers to a sensor disposed at a position away from the sensor unit body. The sensor has a function of sensing the presence / absence of grout material and other necessary information. When the sheath tube has a large fog, by providing an external sensor, the sensor portion can be provided at a shallow position from the concrete surface, and the attenuation of the electromagnetic wave intensity by the concrete can be reduced. In the first embodiment, as the sensor 25, a conductive sensor in which two pieces of platinum that do not contact alumina ceramics are embedded is used. When the moisture of the grout material is absorbed by the ceramics, the electric conductivity changes, so that it can be detected whether the grout material is in contact with the sensor. The sensing parameter may be electrical characteristics such as impedance and conductance in addition to electrical conductivity, or may be a potential difference between different metals. By selecting electrical characteristics as parameters, the grouting material contains a large amount of ions, so the electrical conductivity is larger than that of water, and even if rainwater enters the sheath tube before grouting, the grouting by filling Can be sensed selectively, and a highly sensitive sensor can be constructed. Further, the sensor may sense the grout material by a current flowing through the grout material flowing between the terminals to which a voltage is applied. Since the grout material contains a large amount of ions, it is possible to construct a sensor having a higher electric conductivity and higher sensitivity than water. In addition, since the power consumed for measuring the electrical conductivity is small, the power storage / power supply unit can be made small.

  The type of sensor may be a temperature sensor, a humidity sensor, various ion sensors, or the like, or these may be used in combination. As the temperature sensor, for example, a temperature measuring device such as a resistance temperature detector may be used to sense the temperature of the grout material itself or heat generated during curing. In addition, an alkali-soluble resin or water-soluble polymer made mainly of polyimide, modified vinyl acetate, carboxymethylcellulose, etc. is used to provide a switch that changes the electrical signal when these substances are dissolved when the grout material is filled. There is a method of detecting a difference in heat capacity between the grout material and air using a temperature sensor together with a heating device.

  The sensor control unit 26 efficiently operates the power necessary for the sensor 25 to drive, the voltage and current necessary for the sensor to sense, the frequency and the waveform when using the pulse wave, and the like. To control. The sensor control unit 26 transmits a signal sensed by the sensor 25 to the CPU 21. The CPU 21 may have the function of the sensor control unit 26.

  The modulation / demodulation unit 27 modulates the signal that the grout material is present together with the identification code of the sensor unit 2 and transmits the modulated signal to the antenna 28. The antenna 28 transmits information on the grout material to the outside. As the antenna 28, a conductive material such as metal, carbon fiber, or ferrite is used. It is desirable to use in the form of a hollow winding or a magnetic winding, and the above material may be sandwiched between films such as PET. Further, the shape may be molded into an appropriate shape such as a ring shape, a rod shape, or a disk shape. The demodulation unit of the modulation / demodulation unit 27 demodulates the electromagnetic wave sent from the reading device, transmits information on sensor control sent from the reading device, information such as the identification code of the sensor unit to the ROM via the CPU, and the reading device. The electric power for driving the sensor unit is taken out from the electromagnetic wave sent from and transmitted to the power storage / power supply unit. The modulation / demodulation unit 27 may have only a modulation function without a demodulation function. Note that the frequency of wireless communication is determined to be a frequency suitable for penetrating the depth from the antenna embedded in the concrete to the concrete surface while taking into account the relationship between the amount of information and the frequency. A frequency in the range of ~ GHz can be used. Also, the antenna size suitable for the frequency is determined.

  By adopting the configuration as described above, it is possible to provide the detector with a function of sensing information, performing certain processing inside, and transmitting the information together with sensor identification information. As a result, it is possible to easily confirm whether or not the grout material is filled from the outside of the concrete structure.

  On the other hand, the reading device 3 includes an antenna, a modulation / demodulation device, a memory, a CPU, and a power supply unit. FIG. 4 is a block diagram showing an electrical configuration of the reading device 3. As shown in FIG. 4, the reading device 3 includes a CPU 31, a power supply unit 32, a ROM 33, a RAM 34, an antenna 35, a modulation / demodulation unit 36, and an external output terminal 37. The CPU 31 controls the reading device according to a preset program, and performs data processing of transmission / reception signals, processing of information received by the antenna, power supply control, and other data processing. Information processed by the CPU 31 is output to the output device through the external output terminal 37. Finally, information on the filling status of the grout material can be obtained by displaying the output device. Note that a display unit may be provided in the reading device.

  The power supply unit 32 supplies power necessary for driving each block of the CPU 31, the ROM 33, the RAM 34, and the modulation / demodulation unit 36 included in the reading device 3. The reading device 3 has a built-in memory, and the memory includes a ROM 33 and a RAM 34. The ROM 33 stores a program for processing a signal received by the antenna, a program for controlling the entire sensor unit, a program for controlling the sensor and determining the presence or absence of a grout material, an identification code unique to the sensor unit, and the like.

  By using the identification code in this manner, information from a plurality of sensors or sensor units can be processed at the same time, and the grout material filling status can be detected. Further, it is possible to adopt a configuration in which information is read by passing a concrete structure such as a girder in which a sensor portion is embedded in an annular reading device. Thereby, information with higher accuracy can be obtained. It should be noted that the reader may not be able to receive electromagnetic waves without using an identification code and approaching each sensor unit within a certain range. In this case, the configuration of the apparatus can be simplified.

  The ROM 33 stores a control program for controlling the operation of the entire reading apparatus, including a program for transmitting a signal to the external output terminal. The RAM 34 records the state of the presence / absence of the grout material, information on the embedding position of the sensor unit, and other necessary information.

  The ROM 33 and the RAM 34 include not only a completely read-only memory but also a so-called EEPROM (electrically erasable programmable ROM). In this case, the EEPROM stores a program for rewriting data and detecting the state of the structure. Thereby, the response | compatibility according to the design of a structure or the condition of the field can be taken. Further, an identification code corresponding to each embedded sensor may be recorded in the memory.

  FIG. 5 is a cross-sectional view showing a sensor unit and a sheath tube to which the sensor unit is attached. Of the members of the sensor unit 2, the sensor 25, the antenna 28, the IC chip 40, and the protective case 41 are schematically shown. The sensor 25 includes an electrode 25a and a dielectric 25b. Alumina-based ceramics are used for the dielectric. For example, it is utilized that electrical characteristics such as electrical conductivity of a member between the electrodes change due to penetration of moisture of the grout material. In addition to alumina-based ceramics, other materials whose electrical characteristics are changed by injection of a grout material may be used. By selecting electrical characteristics as parameters, grout material can be selectively sensed.

  The IC chip 40 functions as the CPU 21, RAM 23, ROM 24, sensor control unit 26, modulation / demodulation unit 27, and power storage / power supply unit 22. The protective case 41 is a case for protecting the IC chip 40 and the like, which are the contents of the sensor unit, from the pressure received from the sheath tube by construction and the components of the concrete or grout material. As the material of the protective case, it is desirable to use a material such as a resin excellent in alkali resistance, water resistance, load resistance and impact resistance. As shown in FIGS. 1, 2, and 5, the shape may be an ellipsoid or an elliptic cylinder so that stress concentration does not occur in one place, or may be a rectangular parallelepiped in consideration of ease of handling.

  In the first embodiment, the sensor 25 measures the change in the electrical characteristics of the dielectric due to the permeation of moisture in the grout material, but may be a sensor based on other methods. FIG. 6 is a cross-sectional view of a sensor and a sheath tube using an alkali-soluble resin. A voltage is applied to the fixed electrode 51 so that a current flows when the movable electrode 50 comes into contact, and the fixed electrode 51 and the movable electrode 50 function as a switch. The spring 52 applies a force to the movable electrode 50 toward the fixed electrode. The shaft 54 is fixed to the movable electrode 50 at one end, and is fixed to the plate 55 at the other end. The stopper 53 is provided between the plate 55 and the switch case 56, and the movable electrode 50 is kept out of contact with the fixed electrode 51. The stopper 53 is made of an alkali-soluble resin or a water-soluble polymer made mainly of polyimide, modified vinyl acetate, carboxymethyl cellulose, or the like. Thereby, the stopper 53 is melted by contacting the grout material, the movable electrode is pressed against the fixed electrode by the force of the spring, and the switch is electrically connected. As a result, the sensor can sense the grout material and output an electrical signal.

  As described above, a sensor using a soluble resin adopts a simple mechanical method, not an analog method or a method using an encoded electric signal. By adopting such a configuration, it is possible to sense the filling condition of the grout material with an inexpensive and simple sensor. In this case, since a power source is unnecessary, it is possible to maintain the function for a long time in an unused state. In addition, since a sensor using an alkali-soluble resin does not react with neutral water, it is possible to eliminate the need for on-site waterproofing measures.

  In addition, the same effect can be acquired if the material of a stopper melt | dissolves by contacting a grout material. In addition to the configuration shown in FIG. 6, a bent configuration using an elastic plate instead of the spring may be employed. Thereby, a member can be decreased and a structure can be simplified further.

  Next, a grout filling state confirmation method using the grout filling state detection apparatus according to the first embodiment configured as described above will be described. FIG. 7 is a flowchart illustrating a grout material filling state confirmation method using the grout material filling state detection device according to the first embodiment.

  First, a plurality of sensor parts are attached to the sheath tube at intervals in the length direction (step S1). Next, the sheath tube to which the sensor unit including the sensor using the electrical conductivity as described above is attached is arranged at a predetermined position according to the design of the structure or the situation at the site (step S2). Concrete is cast so as to fill the arranged sheath tube (step S3) and cured (step S4). Next, a PC steel material is inserted into the sheath tube and is tensioned using a jack or the like (step S5). Next, a grout material is injected into the sheath tube (step S6). It waits for about one hour until the change of the detected current is stabilized, and the grout filling state detection device is operated (step S7). Next, from the display of the output device connected to the reading device, it is confirmed whether or not the grout material is filled at all detection positions (step S8). Inject the grout material.

  In this way, even when the sheath tube is disposed at a deep position from the concrete surface, it is possible to easily know the filling condition of the grout material in a non-destructive manner. In addition, it is possible to easily check whether or not the grout material is filled without using wiring from the outside of the concrete structure. As a result, a durable structure can be constructed without corrosive factors that impair the durability of the concrete structure entering through the wiring.

  As described above, the filling state of the grout material can be confirmed in the prestressed concrete construction. As a specific example, a case where a prestressed concrete girder is used for construction of a bridge will be described. FIG. 8 is a schematic cross-sectional view of a sheath tube and a sensor portion embedded in a prestressed concrete girder. Symmetrically shaped girders are joined at the center. The length in the extending direction of the girder sheath tube is about 15 m. Both ends of the combination of two digits are fixed. The sheath tube is embedded in each girder while being bent into a convex shape. Thereby, the crack of concrete can be controlled efficiently by tensioning PC steel materials. In FIG. 8, the rib of the sheath tube is omitted.

  As shown in FIG. 8, a plurality of sensor units are attached in contact with the sheath tube at intervals in the length direction of the sheath tube. The attachment position of the sensor unit can be arbitrarily determined depending on the form of construction, but in the specific example shown in FIG. 8, it is provided on the upper surface of the sheath tube at a constant interval. In order to construct a structure by connecting two girders with a convexly projecting sheath pipe, the sheath pipe has a convex shape at the joint part of the central girder, and the tensioned PC steel material is inside the sheath pipe. It will touch the lower side of. In this central portion, if there is a sensor portion on the upper side of the sheath tube, it is possible to detect unfilling due to an air reservoir in the vicinity of the central portion caused by the forward flow phenomenon of the grout material. If the sensor at this position senses a signal with a grout material, it can be detected that at least a grout material sufficient to fill the PC steel material has arrived. As a result, it is possible to reliably obtain the minimum necessary information as to whether or not the grout material is substantially filled and the PC steel material is covered.

(Embodiment 2)
In the first embodiment, the sensor unit 2 is arranged on the sheath tube and embedded in the concrete. As shown in the second embodiment, a sensor unit is previously attached to the sheath tube at a factory or the like. It is also possible to finely adjust the position of the sensor unit on site and embed it in concrete. FIG. 9 is a cross-sectional view showing an example of a sheath tube to which a sensor unit is attached. The sensor part 2 attached to the rib 4a of the sheath tube 4 in the shape of a semi-elliptical cylinder is attached. FIG. 10 is a cross-sectional view in which the sensor unit 2 is further enlarged. The outer shape of the protective case of the sensor unit 2 is formed in the shape of a semi-elliptical column so as to be in close contact with the inner surface of the rib 4a of the sheath tube. Thereby, a sheath pipe | tube and a sensor part closely_contact | adhere and can reduce a space | gap. The outer shape of the protective case of the sensor unit may be a semi-ellipsoid, an elliptic cylinder, or an ellipsoid. The sensor unit 2 includes an IC chip and a built-in sensor, and is arranged so that the surface of the sensor is at the position of the inner diameter of the sheath tube. The antenna portion is connected to the wiring extending from the IC chip and is provided inside the sheath tube. Thus, since the sensor portion is provided inside the sheath tube, it is not necessary to make a hole in the sheath tube. As a result, the anticorrosion effect of the sheath tube can be maintained.

  Thus, in Embodiment 2, after manufacturing the sheath pipe | tube which attached the sensor part so that the filling condition of grout material can be detected previously, it is carried to the spot which constructs a concrete structure, and is embed | buried. In addition, you may attach so that a fine adjustment can be performed, without fixing the position of a sensor part. Thereby, a sensor part can be suitably arrange | positioned in the position which wants to know the filling condition of the grout material of a sheath pipe | tube by the design of a structure, or the condition of a construction site. In addition, it is complicated to attach the sensor unit in the field from the viewpoint of facilities and personnel, but such complexity can be eliminated by attaching the sensor unit to the sheath tube in advance. Further, since the sensor unit transmits information by wireless communication, the sensor unit can be arranged without any particular limitation.

(Embodiment 3)
In Embodiment 1, an antenna is provided in advance as a member of the sensor unit. However, a sheath tube or a PC steel material may be provided with a function as an antenna of the sensor unit. FIG. 11 is a perspective view of a grout filling state detection device when a metal sheath tube is made to function as an antenna. Terminals 60 extending from the sensor portion are connected to the sheath tube at two locations. By connecting to the sheath tube at a distance as described above, the sheath tube can have an antenna function of transmitting and receiving electromagnetic waves, and electromagnetic waves can be efficiently transmitted and received. Connection to the sheath tube may be through a suitable capacitance.

  In the third embodiment, since the size of the sheath tube or the PC steel material is the size of the antenna, the frequency of the electromagnetic wave to be used may be 6 GHz or less in order to increase the efficiency of electromagnetic wave transmission / reception. A range of MHz to 1 GHz is preferred. One wiring may be connected to the sheath tube as a ground, and the other wiring may be connected to an external antenna embedded in concrete or a built-in antenna in the sensor unit.

  By taking the configuration as described above, the number of members necessary for the configuration of the detector can be reduced. In addition, the same effect can be obtained as when the antenna is provided with a cover from the concrete surface to the embedded position of the sheath tube, etc. When the sheath tube is in a shallow position, information is read by wireless communication from the sensor unit. It can be easily read by the device.

  Moreover, in Embodiment 3, as shown in FIG. 11, the sensor is attached to the sheath tube as an external sensor. Thus, the function of an antenna can be stabilized by taking a composition which controls a plurality of external sensors by one sensor part, and integrates wiring to an antenna. The size and shape of the sheath tube as an antenna is determined by the fog from the concrete surface to the sheath tube and the frequency of the electromagnetic wave used.

  The filling of grout material in the construction of post-tension type T-type prestressed concrete was detected. After arranging the prestressed concrete with a length of 32 m designed according to the road bridge instructions, four sheath tubes made of steel and having an outer diameter of 68 mm were placed in the girder.

  The sensor unit having the configuration shown in FIG. 5 was used. For the antenna, a ferrite core was used as the material, and a type built in the sensor unit was used. The sensor used was embedded with two pieces of platinum that did not contact the alumina ceramics. With this sensor, the presence of the grout material was detected by utilizing the fact that the electrical characteristics change as the moisture of the grout material penetrates into the ceramics.

  Five sensor parts of the present invention were attached to four sheath tubes arranged in the beam. For attachment, the sensor part was placed outside the sheath tube, and only the sensor was placed inside the sheath. The sensor part was embedded as a position deeper than 35 mm from the concrete surface. The sensor unit includes a sensor, a modulation / demodulation unit, a CPU, a memory, an IC chip including a sensor control unit, an antenna, and a power storage unit, and communication between the sensor and the reading device is 134.2 kHz.

  After attaching the sensor part, concrete was cast and steam curing was performed, and the mold was removed. After curing for 2 weeks, a 12S12.7B PC steel material (tension material) was inserted and strained. The grout material used for filling was manufactured using commercially available grout admixtures in four types of water cement ratios of 28%, 35%, 45% and 55%, and four sheath tubes were used for each water cement ratio. Injected. The grout pump is used to inject from one side of the sheath tube at an injection speed of 10 liters / minute, and 2 / of the design quantity of the grout material calculated from the porosity of the sheath tube and the PC steel material and the length of the sheath tube. An amount of 3 was injected. After the injection, the filling condition of the grout material was confirmed using a reader.

  As a result, in the grout material filling detection apparatus of the present invention, in any sheath tube, the grout material is filled with sensors arranged at three positions from the side closer to the injection port, and the grout material is not filled at the remaining two locations. Was detected. This result is consistent with the filling condition of the grout material confirmed by drilling, and it was found that the filling condition of the grout material in the prestressed concrete construction can be detected by the system of the present invention.

  With respect to a concrete slab having a thickness of 30 cm in which a polyethylene sheath tube having an outer diameter of 76.5 mm is disposed at the center in the plate thickness direction, the presence or absence of filling of the grout material into the sheath tube was detected.

  The sensor unit includes a sensor, a modulation / demodulation unit, a CPU, a memory, an IC chip including a sensor control unit, an antenna, and a power storage unit. Part of the antenna was taken out of the sensor unit as an iron wire and wound around PC steel so that the PC steel could be used as part of the antenna. Further, an identification code is attached to the memory, and the sensor unit mounting position and the identification code on the PC steel material are recorded in advance, and the frequency of wireless communication performed between the sensor unit and the reader is 835 MHz. A sensor as shown in FIG. 6 is used for the sensor of the sensor unit, and an alkali-soluble resin mainly composed of polyimide is used, and the grout material is alkaline and the soluble resin is dissolved and switched on.

  The PC steel material in which the sensor part was installed was inserted into the sheath tube, and grouting was performed with a cement-based grouting material. One hour after the completion of the grout construction, the presence or absence of the grout material was confirmed using a reader, and the sensor detected that the grout material was filled at any position. After curing the grout material, the sheath tube was pulled out from the concrete to confirm that the grout material was filled, and it was confirmed that the grout material filling status detection device of the present invention was operated effectively.

  In addition, although this invention relates to the apparatus or method which detects the presence or absence of filling of grout material, this invention is applicable also in the construction filled with cement compositions, such as concrete. That is, in deep parts from the concrete surface where the filling property is a concern, for example, parts that may cause junkers due to dense reinforcement, tunnel backfilling, placement of cement composition into underground structures, etc. Its fillability can be easily confirmed.

2 is a perspective view of a grout filling state detection device and a sheath tube according to Embodiment 1. FIG. It is sectional drawing of the filling condition detection apparatus of a grout material which concerns on Embodiment 1, and a sheath pipe | tube, a concrete structure, PC steel material, and a grout material. It is a block diagram which shows the electric constitution of a sensor part. It is a block diagram which shows the electric constitution of a reader. It is sectional drawing which shows the sheath pipe | tube which attached the sensor part and the sensor part. It is sectional drawing of the sensor and sheath tube using alkali-soluble resin. 5 is a flowchart showing a grout material filling state confirmation method using the grout material filling state detection device according to the first embodiment. It is a schematic sectional drawing of a sheath pipe and a sensor part embedded in a prestressed concrete girder. 6 is a cross-sectional view showing an example of a sheath tube to which a sensor unit according to Embodiment 2 is attached. FIG. It is sectional drawing which expanded the sensor part which concerns on Embodiment 2 further. It is a perspective view of the grout material filling condition detection device according to the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Grouting material filling condition detection device 2 ... Sensor unit 3 ... Reading device 4 ... Sheath tube 4a ... Rib 5 ... Concrete 6 ... PC steel material 7 ... Grout material 21 ... CPU
22 ... Power storage / power supply unit 23 ... ROM
24 ... RAM
25 ... Sensor 25a ... Electrode 25b ... Dielectric 26 ... Sensor control unit 27 ... Modulation / demodulation unit 28 ... Antenna 31 ... CPU
32 ... Power supply 33 ... ROM
34 ... RAM
35 ... Antenna 36 ... Modulation / demodulation unit 37 ... External output terminal 40 ... IC chip 41 ... Protective case 50 ... Movable electrode 51 ... Fixed electrode 52 ... Spring 53 ... Stopper 54 ... Shaft 55 ... Plate 56 ... Switch case 60 ... Terminal

Claims (5)

A device for detecting the filling state of the grout material filled in the sheath tube in the grout construction with the prestressed concrete structure,
An embedded sensor unit that senses the presence or absence of filling of the grout material and a reading device are provided, and data transmission from the sensor unit to the reading device is performed by wireless communication.
The embedded sensor unit is:
An antenna, a modulation device, and a protective case made of resin that protects them, and is provided outside the sheath tube. The sensor main body is provided outside the sheath tube and transmits data to the reader. The sensor main body is separated from the sensor main body. A grout material filling state detection device , comprising: an external sensor that contacts the sheath tube at a certain position or is attached in the sheath tube and senses the presence or absence of the grout material. A detector used in the sensor unit of the grout material filling status detection device according to claim 1,
A detector having an external sensor attached to a sheath tube at a position away from the sensor body and sensing the presence or absence of a grout material , and an antenna, a modulation device, and a protective case provided in the sensor body . A sheath tube used for grouting in prestressed concrete structures,
The grout material filling status detection device according to claim 1,
One or more external sensors are provided at intervals in the length direction. In the grout construction with the press-rest concrete structure, the grout material filling status confirmation method for the sheath tube using the grout material filling status detection device according to claim 1,
The external sensor senses whether or not the grout material filled in the sheath tube in the grout construction is filled ,
The sensed information is converted into a wireless signal by the sensor unit body and transmitted to the reading device by wireless communication.
A grout material filling status confirmation method, comprising: confirming a grout material filling status in the sheath tube from information received by the reader.   In the above, the sheath tube when the sheath tube is made of metal or the PC steel material inserted into the sheath tube when the sheath tube is not made of metal has an antenna function for transmitting the radio signal. The method for confirming a filling state of a grout material according to claim 4.

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