JP2007033027A - Method of diagnosing ferrous material in concrete structure with ferrous material embedded therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which enables the easy inspection or deterioration diagnosis of the reinforcing rod of a reinforced concrete structure using a magnetic impedance effect sensor. <P>SOLUTION: A sensor is constituted by providing a coil 7x for a bias magnetic field to a magnetic impedance effect element 1x so as to detect the output of the element through a detection circuit. This sensor is used to scan the surface of a ferrous material embedded concrete structure C while passing an exciting current through the magnetic impedance effect element to apply voltage to the bias magnetic field coil to inspect the ferrous material (g) or diagnosing the deterioration of the ferrous material (g). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for diagnosing an iron-based material of an iron-based material-buried concrete structure, and is used, for example, for exploration of a buried position of a buried iron-based pipe, a reinforcing bar or the like and for deterioration diagnosis.

The so-called electromagnetic rebar exploration method is a method of exploring reinforced concrete rebars by passing an alternating current through the rebar, measuring the alternating magnetic field based on the current on the reinforced concrete surface, and exploring the route where the magnetic field peaks. Known as.
As a method for measuring the corrosion degree of a reinforcing bar, a natural potential measuring method is known. As shown in FIG. 7, a reference electrode s (copper sulfate electrode) is connected to a reinforcing bar g by a lead wire w through a potentiometer m. Is connected, and the reference electrode s is moved along the reinforcing bar embedding route of the concrete C, and the electric potential during the movement is measured. When the measured electric potential E (v) is about 0.20 <E, the probability is 90% or more. No corrosion, approximately 0.35 ≦ E ≦ −0.20, uncertain, and when E <0.35, the presence of corrosion is diagnosed with a probability of 90% or more (for example, Non-Patent Document 1)

However, the electromagnetic rebar exploration method can be applied only when current can be applied to the concrete-embedded iron-based material, and the exploration target is limited.
In addition, the self-potential measurement method has a problem that it has a wide uncertainty range and is easily affected by stray current.
Recently, sensors using the magneto-impedance effect have been developed as magnetic sensors. Sensors using this magneto-impedance effect are smaller, more sensitive, have higher spatial resolution, and faster response than Hall sensors, magnetoresistive elements, fluxgate sensors, etc., and a magnetic detection method using this sensor has been proposed. ing.
It has also been reported that a defect in a steel plate is detected by a leakage magnetic flux testing method using this magneto-impedance effect sensor (Non-patent Document 2).
However, in this method, it is necessary to apply a magnetic field to the object to be inspected, and the inspection object is limited.
Civil Engineering Handbook I, Japan Society of Civil Engineers, Chapter 9, Maintenance Management, p1021 Koji Fujimoto, Yoshio Mohri, MAG-98-86, p39-43

By the way, according to the result of earnest examination by the present inventors, it is possible to detect the defect of the object to be inspected with sufficient accuracy even by scanning the iron-based object to be inspected by the magneto-impedance effect type sensor without magnetizing.
Unlike the magnetic flux leakage test method, the ability to detect defects without magnetizing means that the bias magnetic field applied to the magneto-impedance effect element bypasses the iron-based inspected object, which is a magnetic material, and responds to the defect in the inspected object. It is involved that the sensor output is changed by changing the bias magnetic field due to the reluctance change of the object to be inspected.

  An object of the present invention is to provide a method that can easily perform rebar search and deterioration diagnosis of a reinforced concrete structure using a magnetic impedance effect sensor based on the above knowledge.

According to a first aspect of the present invention, there is provided a method for diagnosing an iron-based material of an iron-based material-embedded concrete structure, wherein a magnetic impedance effect element is provided with a bias magnetic field coil and a sensor for detecting the output of the element through a detection circuit is detected by a magnetic impedance. It is characterized in that the iron-based material is searched by scanning the surface of the iron-based material embedded concrete structure while applying an exciting current to the effect element and applying a voltage to the bias magnetic field coil.
According to a second aspect of the present invention, there is provided a method for diagnosing an iron-based material in an iron-based material-embedded concrete structure, wherein a magnetic impedance effect element is provided with a bias magnetic field coil, and a sensor for detecting the output of the element through a detection circuit is detected with a magnetic impedance. Deterioration along the longitudinal direction of the iron-based material by scanning the surface of the structure on the embedded iron-based material of the iron-based material embedded concrete structure while applying an excitation current to the effect element and applying a voltage to the bias magnetic field coil It is characterized by diagnosing the degree.
The method for diagnosing an iron-based material of an iron-based material embedded concrete structure according to claim 3 is the same as the method for diagnosing an iron-based material of an iron-based material embedded concrete structure according to claim 1 or 2, wherein the axial directions are different from each other. A sensor having a multi-dimensional magneto-impedance effect element in which a number of magneto-impedance effect elements are combined.
The method for diagnosing an iron-based material in an iron-based material-buried concrete structure according to claim 4 is the method for diagnosing an iron-based material in an iron-based material-buried concrete structure according to any one of claims 1 to 3, wherein Two-dimensional magneto-impedance effect elements are arranged in parallel, and the detection output of these elements is multi-channeled.
The method for diagnosing an iron-based material of an iron-based material-embedded concrete structure according to claim 5 is the method for detecting an iron-based material of an iron-based material-buried concrete structure according to any one of claims 1 to 4, wherein each channel is detected. Transmitting means for wirelessly transmitting a signal to a spatially separated place is provided.

(1) An amorphous wire as a magneto-impedance effect element has an easily magnetizable outer shell in the circumferential direction, and when the circumferential magnetic field due to the excitation current is shifted from the circumferential direction, the circumferential permeability μθ Changes, the impedance changes due to a change in resistance based on the inductance and skin effect, and the output of the magneto-impedance effect element changes. Therefore, the buried iron pipe and the reinforcing bar are corroded and thinned to change their magnetic properties such as permeability, and the circumferential magnetic field due to the excitation current of the magneto-impedance effect element being moved to the concrete surface is The output of the magneto-impedance effect element is changed by shifting from the circumferential direction due to the change in permeability of the electromagnetic field near the magneto-impedance effect element due to corrosion and thinning of the reinforcing bar. Therefore, it is possible to determine the degree of corrosion / thinning of the embedded iron-based material by using the output change as the corrosion / thinning information.
(2) With respect to the bias magnetic field generated by the bias magnetic field coil, the embedded iron material also becomes a part of the circuit of the magnetic field, and the strength of the bias magnetic field changes according to the degree of corrosion and thinning of the embedded iron material. To do. Since this bias magnetic field passes through the amorphous wire as the magneto-impedance effect element in the axial direction, the circumferential magnetic field due to the excitation current is shifted from the circumferential direction, and the degree of the shift is corrosion / thinning of the embedded iron-based material. It changes according to the degree. Accordingly, the output change of the magneto-impedance effect element correlates with the degree of corrosion / thinning of the embedded iron-based material, and the degree of corrosion / thinning of the embedded iron-based material can be determined from the output change.
(3) Since the magneto-impedance effect element has a multi-dimensional structure and the corrosion / thinning of the embedded iron material is obtained from multiple directions, even if the embedded iron material is a linear object such as a reinforcing bar・ Thinning information can be obtained with high sensitivity.
(4) Since a plurality of magneto-impedance effect elements are arranged in parallel and the deterioration diagnosis apparatus is scanned in the direction orthogonal to the arrangement direction, the number of scanning operations can be reduced, so that the number of work steps can be reduced.
(5) The number of channels is increased, and the detection signal of each channel can be transmitted to a computer in a wireless manner to easily detect the deterioration state of the embedded iron-based material from a remote location.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a circuit diagram of a magneto-impedance effect sensor used in the present invention.
In FIG. 1, reference numeral 1 denotes a magneto-impedance effect element, which has a zero magnetostriction or a negative magnetostriction having an outer shell portion in which magnetic domains whose spontaneous magnetization directions are opposite to each other in the circumferential direction of the wire are alternately separated by domain walls. Amorphous alloy wire is used. The inductance voltage component in the output voltage between both ends of the wire generated when a high-frequency excitation current is passed through an amorphous magnetic wire having zero magnetostriction or negative magnetostriction is obtained by the circumferential magnetic flux generated in the cross section of the wire. This occurs because the easily magnetizable outer shell is magnetized in the circumferential direction. Therefore, the circumferential permeability μ _θ depends on the circumferential magnetization of the outer shell. Thus, when a signal magnetic field is applied in the axial direction of the amorphous wire being energized, the outer shell portion having the easily magnetizable property in the circumferential direction is obtained by synthesizing the circumferential magnetic flux and the signal magnetic field magnetic flux by the energization. direction of magnetic flux acting deviates from the circumferential direction, correspondingly hardly occur magnetization in the circumferential direction, the circumferential permeability mu _theta changes, the inductance voltage content will vary to. This fluctuation phenomenon is called a magnetic inductance effect, which can be said to be a phenomenon in which the high-frequency excitation current (carrier wave) is modulated by a signal magnetic field (signal wave). Further, when the frequency of the energization current is in the order of MHz, a high-frequency skin effect appears greatly, and the skin depth δ = (2ρ / wμ _θ ) ^1/2 (μ _θ is the circumferential permeability, ρ as described above. electrical resistivity, w is shows the angular frequency, respectively) is changed by mu _theta, so changed by this as μθ is the signal magnetic field, the resistance voltage of the in wire ends between the output voltage also varies with the signal magnetic field It becomes like this. This fluctuation phenomenon is called a magneto-impedance effect, which can be said to be a phenomenon in which the high-frequency excitation current (carrier wave) is modulated by a signal magnetic field (signal wave).

In FIG. 1, 2 is a high-frequency current source circuit for applying a high-frequency excitation current to the magneto-impedance effect element, and 3 is a signal magnetic field H (signal wave) acting in the axial direction of the magneto-impedance effect element. 4 is an amplifier circuit for amplifying the demodulated wave, 5 is an output terminal, 6 is a negative feedback coil, and 7 is a bias magnetic field coil.
For the magneto-impedance effect element 1, an amorphous ribbon, an amorphous sputtered film, or the like can be used in addition to an amorphous wire having zero magnetostriction or negative magnetostriction.

In the magneto-impedance effect element 1, as described above, the direction of the magnetic flux acting on the outer shell portion that is easily magnetized in the circumferential direction is obtained by combining the circumferential magnetic flux based on the excitation current and the axial magnetic flux due to the signal magnetic field. Since the circumferential permeability μ _θ is changed from the circumferential direction, the inductance is changed, and the impedance is changed by changing the skin depth of the high frequency skin effect of the circumferential permeability μ _θ . Therefore, the circumferential displacement φ due to the composite magnetic field becomes ± φ due to ± of the signal magnetic field, but the reduction factor cos (± φ) of the circumferential magnetic field does not change, so the degree of decrease of μθ is positive or negative in the direction of the signal magnetic field. Does not change. Therefore, the signal magnetic field-output characteristic is substantially symmetrical with respect to the y axis when the signal magnetic field is taken on the x axis and the output is taken on the y axis as shown in FIG. This signal magnetic field-output characteristic is non-linear. Non-linear characteristics are unstable and high-sensitivity measurement is difficult. Therefore, negative feedback is applied by a negative feedback coil to linearize the output characteristics as shown in FIG. However, with this output characteristic, since the polarity of the signal magnetic field cannot be determined, a bias magnetic field is applied by the bias coil 7 so that the polarity can be determined as shown in FIG. That is, the characteristic of (b) in FIG. 2 is moved in the negative direction of the x-axis by the bias magnetic field -Hb as shown in (c) of FIG. 2, and the maximum detection range of the signal magnetic field is within the range of the single diagonal line region. -Hmax to + Hmax.
From FIG. 2C, it can be understood that the output when the signal magnetic field Hex is 0 is changed by the change ΔHb of the bias magnetic field.

The magneto-impedance effect element 1 is an alloy of transition metal and non-metal having a non-metal composition of 10 to 30 atomic%, particularly an alloy of transition metal and non-metal, and the amount of non-metal accounts for 10 to 30 atomic%. The transition metal is Fe and Co and the nonmetal is B and Si, or the transition metal is Fe and the nonmetal is B and Si. For example, the composition Co _70.5 B ₁₅ can be used. Si ₁₀ Fe _{4.5 having} a length of 2000 μm to 6000 μm and an outer diameter of 30 μm to 50 μmφ can be used.

  In the above, a normal high frequency such as a continuous sine wave, a pulse wave, or a triangular wave can be used as the high frequency excitation current, and examples of the high frequency excitation current source include a Hartley oscillation circuit, a Colpitts oscillation circuit, a collector tuning oscillation circuit, and a base tuning oscillation. In addition to a normal oscillation circuit such as an oscillation circuit, a square wave generator that integrates the square wave output of a crystal oscillator through a direct current cut capacitor with an integration circuit and amplifies the triangular wave of this integration output with an amplification circuit, and oscillates a COMS-IC The triangular wave generator etc. which were used as a part can be used.

As the above detection circuit, for example, a configuration in which a modulated wave is half-wave rectified by an operational amplifier circuit and this half-wave rectified wave is processed by a parallel RC circuit or an RC low-pass filter to obtain an envelope output of the half-wave rectified wave, A configuration in which the modulated wave is half-wave rectified by a diode and the half-wave rectified wave is processed by a parallel RC circuit or an RC low-pass filter to obtain an envelope output of the half-wave rectified wave can be used.
Further, it is possible to use tuning detection in which a signal wave is sampled by multiplying the modulated wave by a square wave having a frequency fs tuned to the modulated wave (frequency fs).
In the above embodiment, the detected magnetic field is extracted by demodulating the modulated wave. However, the present invention is not limited to this, and the high-frequency excitation current wave (carrier wave) modulated by the signal magnetic field (signal wave) acting on the magneto-impedance effect element. Any suitable detecting means can be used as long as it can detect the signal magnetic field.

The negative feedback coil and the bias magnetic field coil can be wound around a magneto-impedance effect element. Further, as shown in FIG. 3, a negative feedback coil and a bias magnetic field coil can be wound around an iron core constituting a magneto-impedance effect element and a loop magnetic circuit. 3 (a) is a side view showing an example of a magneto-impedance effect unit with an iron core coil, FIG. 3 (b) is a bottom view, and FIG. 3 (c) is a cross-sectional view of FIG. It is sectional drawing.
In FIG. 3, reference numeral 100 denotes a substrate chip, and for example, a ceramic plate can be used. Reference numeral 101 denotes an electrode provided on one side of the substrate piece, and includes a magneto-impedance effect element connecting projection 102. This electrode can be provided by printing and baking a conductive paste, for example, a silver paste. 1x is a magneto-impedance effect element connected between the protrusions 102 and 102 of the electrodes 101 and 101 by soldering or welding, and an amorphous wire, amorphous ribbon, sputtered film, or the like having zero or negative magnetostriction can be used as described above. 103 is a C-type iron core made of iron or ferrite, 6x is a negative feedback coil wound around the C-type iron core, 7x is a bias magnetic field coil, and the magneto-impedance effect element 1x and the C-type iron core 103 The both ends of the C-type iron core 103 are fixed to the other surface of the substrate piece 100 with an adhesive or the like so as to constitute a loop magnetic circuit. The iron core material may be a magnetic material having a small residual magnetic flux density. Examples thereof include permalloy, ferrite, iron, amorphous magnetic alloy, magnetic powder mixed plastic, and the like.

According to the present invention, in order to search for an embedded iron-based material of an iron-based material embedded concrete structure, for example, an iron pipe, (a) [plan view] and (b) in FIG. As shown in FIG. 2, the magneto-impedance effect sensor Se is scanned along the surface of the iron-based material embedded concrete structure C.
FIG. 4B shows the action state of the bias magnetic field during scanning.
4A and 4B, 1x is the magneto-impedance effect element of the magneto-impedance effect unit with iron core coil shown in FIG. 3, 103 is the iron core, 7x is the coil for the bias magnetic field, and g is the iron pipe. Since the iron pipe g is a magnetic body, a bias magnetic field is bypassed to the iron pipe g.
The reluctance of the iron core 103 is R ₁₀₃ , the reluctance of the magneto-impedance effect element 1x is R ₁ , the reluctance of the iron pipe g is R _g , the reluctance between the end of the magneto-impedance effect element and the iron pipe is R _C , the bias current is I, the bias When the number of turns of the field coil 7x N, the bias magnetic flux passing through the magnetic impedance effect element 1x and B _1, the bias magnetic flux is given by the current B ₁ of the equivalent circuit shown in Figure 4-3, the bias magnetic field Hb is magnetic impedance Hb = B ₁ / μ where μ is the magnetic permeability of the effect element
Given in.

According to the verification results of the present inventors, the detection output varies depending on the magnitude of the distance x shown in FIG.
This is considered to be because the detection output Eout when the bias magnetic field B ₁ / μ (Hb) changes and the external magnetic field Hex = 0 shown in FIG.
When the distance x in FIG. 4A increases, the detection output does not fluctuate. This is because the reluctance _RC between the end of the magneto-impedance effect element and the iron pipe is large, and the bias magnetic flux B ₁ passing through the magneto-impedance effect element is constant without bypassing the bias magnetic field to the iron pipe (reluctance R _g ). Is recognized.
In FIG. 4A, if the magneto-impedance effect sensor Se is scanned so that the distance x is 0, the scanning locus is immediately above the iron pipe g, and the detection output at that time is maximized. Therefore, if the magneto-impedance effect sensor is scanned so as to maximize the detection output, the buried route of the iron pipe can be searched.

In this case, if the steel pipe has deteriorated due to corrosion, thinning, etc., the reluctance changes according to the degree of the deterioration, and the maximum detection output fluctuates according to the change of the reluctance and the deterioration information is transmitted. The In the above description, the change in reluctance is grasped only from the longitudinal direction of the iron-based material. However, if this longitudinal direction is defined as the z direction and the reluctance change is grasped in a multidimensional manner such as the x direction and the y direction, deterioration information with higher accuracy can be obtained. Can be obtained.
Therefore, it is preferable to use a three-dimensional magneto-impedance effect sensor in which three magneto-impedance effect elements are combined in the x-axis direction, the y-axis direction, and the z-axis direction.
FIG. 5 shows a main part of an example of a three-dimensional magneto-impedance effect sensor. A magnetic impedance effect unit _U1z with an iron core coil is _placed on one side of a flexible substrate p in the z-axis direction, and an iron core coil is _placed on the other surface of the flexible substrate p. The magnetic impedance effect unit U _1x with a magnetic core is mounted in the x-axis direction, and the magnetic impedance effect unit U _1y with an iron core coil is mounted in the y-axis direction on the bent rising surface p ′ of the flexible substrate p. The magnetic impedance effect, the bias magnetic field coil, and the negative feedback coil of the magnetic impedance effect unit with a core coil are connected in series.

FIG. 6A is a circuit diagram of another sensor used in the present invention, and FIG. 6B is an external view of the sensor.
6A, C1 to Cn are a plurality of channel detection systems, 11 to 1n are magneto-impedance effect elements, 71 to 7n are bias magnetic field coils for the magneto-impedance effect elements, and 31 to 3n are each In the detection circuit for the magneto-impedance effect element, reference numerals 41 to 4n denote amplification circuits, and reference numerals 61 to 6n denote negative feedback coils.
811 to 81n are multi-channel A / D converters / modulators that digitize detection signals of the respective channels and modulate the carrier waves of the frequencies of the respective channels with the respective digital signals, and 82 is a multi-channel transmitter that transmits the modulated signal wave in a wireless manner. 83 is a receiver, and 84 is a computer that demodulates the received wave and extracts a digital signal for analysis.
Examples of wireless systems that can be used include SS wireless, Bluetooth, wireless LAN, infrared, and the like, and the use of wireless LAN is particularly preferable.

In FIG. 6B, P is a substrate. _Reference numerals 1 _u1 to 1 _un denote magneto-impedance effect units with iron core coils shown in FIG. 3, and the number corresponding to the number of channels is arranged in parallel in the vertical direction at the edge of the substrate P. B is an IC circuit in which an exciting current source circuit and all-channel detection circuits and amplifier circuits are integrated, and E is a battery as a + Vcc power source for the exciting current source circuit, a + Vcc power source for a bias magnetic field coil, and a + Vcc power source for an amplifier circuit. 810 is a multi-channel A / D converter that digitizes the detection signal of each channel, 820 is a wireless transmitter that modulates the carrier wave of each channel frequency with each digital signal and transmits it in a wireless manner, and 834 is a modulated wave. It is a computer that receives and demodulates and extracts and analyzes the digital signal.

In order to search for an embedded iron-based material of an iron-based material embedded concrete structure according to the present invention using this sensor, the surface of the iron-based material embedded concrete structure is scanned by the sensor.
It can be known that the iron-based material is embedded in the path through which the magneto-impedance effect element of the channel where the output change has occurred, and the degree of deterioration of the iron-based material can be diagnosed by analyzing the output. In addition, the carrier wave of the frequency corresponding to the channel is modulated with the detection signal of each channel and transmitted to the computer by radio, the modulated wave of each channel is demodulated, and the signal of each channel is analyzed by the computer. Exploration and diagnosis from
FIG. 6-3 shows a diagnostic method in the case where the embedded iron system material is a single strip such as a drainage iron pipe, and the sensor is scanned along the surface of the iron pipe embedded concrete structure in the longitudinal direction of the iron pipe, If the magneto-impedance effect unit that takes the closest distance to the iron pipe g as shown in FIG. 6-3 (a) is 1 _um , only the channel m as shown in FIG. System material exploration information can be output, and the output fluctuation can be analyzed to diagnose the degree of deterioration of the iron pipe.
FIG. 6-4 shows a diagnostic method when the embedded iron-based material is a parallel multiple strip such as a reinforcing bar. The sensor is scanned in the longitudinal direction of the reinforcing bar along the surface of the reinforced concrete structure. When the magnetic impedance effect unit to take the distance close to the rebar g as shown in (b) is assumed to be _{1 u3, 1 u7, 1 u11} , channel as shown in (b) of FIG. 6-4 3, 7, 11 Can output iron-based material exploration information, and can analyze the output fluctuation to diagnose the degree of deterioration of the reinforcing bars. In this case, it is effective to set the interval between the magnetic impedance effect units to be sufficiently narrower than the interval between the reinforcing bars, and is usually set to 3 mm to 30 mm.

  FIG. 6-5 shows an example of the actual measurement result of the channel output. The output changes between the scanning distances of 1000 mm, and the iron-based structure is identified by specifying the position of the iron-based structure embedded wall surface from this output change position. Can detect the position of defects.

  In the above example, one one-dimensional or multidimensional magneto-impedance effect element is used for one channel, but two one-dimensional or multidimensional magnetic elements arranged at a predetermined distance with respect to the scanning direction. An impedance effect element can be used for one channel, and the outputs of both magneto-impedance effect elements can be differentially amplified. In FIG. 4B, if the direction of the magneto-impedance effect element is the vertical direction, for example, two vertical arrangements, two horizontal arrangements, and two horizontal subordinates can be used. In this way, external magnetic field noise and internal noise can be canceled for differential.

  INDUSTRIAL APPLICABILITY The present invention can be particularly suitably used for exploration and deterioration diagnosis of reinforced concrete structures (for example, foundations and dams of nuclear power plants) and block fences, and exploration and deterioration diagnosis of pipes and pipes in reinforced concrete houses.

It is a circuit diagram which shows the magneto-impedance effect sensor used in this invention. It is drawing which shows the detection characteristic of a magnetoimpedance effect element. It is drawing which shows the magnetic impedance effect unit with an iron core coil used in the said magnetic impedance effect sensor. It is drawing used in order to demonstrate the diagnostic method of the embedded iron-type material of the iron-type material embedded concrete structure which concerns on this invention. 3 is a diagram illustrating an action state of a bias magnetic field during scanning in the present invention. 3 is a diagram showing a current circuit equivalent to a magnetic circuit of a bias magnetic field during scanning in the present invention. It is drawing which shows the principal part of another example of the magneto-impedance effect sensor used in this invention. It is a circuit diagram of the magneto-impedance effect sensor device used in the present invention. It is drawing which shows the external appearance of a magnetic impedance effect sensor apparatus same as the above. It is drawing which shows the Example of this invention using a magnetic impedance effect sensor apparatus same as the above. It is drawing which shows another Example of this invention using a magneto-impedance effect sensor apparatus same as the above. It is drawing which shows an example of the detection waveform of a magnetic impedance effect sensor apparatus same as the above. It is drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magneto-impedance effect element 2 Excitation current source circuit 3 Detection circuit 4 Amplifying circuit C Iron-based material embedded concrete structure g Embedded iron-based material C1-Cn Detection circuit for 1 channel 11-1n Magneto-impedance effect element 71-7n Bias magnetic field Coils 811-81n A / D converter / modulator 82 Wireless transmitter 83 Receiver 84 Computer

Claims (5)

A magnetic field effect coil is attached to the magneto-impedance effect element, and a sensor that detects the output of the element through a detection circuit is applied to the iron-based material while applying an excitation current to the magneto-impedance effect element and applying a voltage to the bias field coil. A method for diagnosing an iron-based material in an iron-based material buried concrete structure, wherein the surface of the buried concrete structure is scanned to search for the iron-based material. A magnetic field effect coil is attached to the magneto-impedance effect element, and a sensor that detects the output of the element through a detection circuit is applied to the iron-based material while applying an excitation current to the magneto-impedance effect element and applying a voltage to the bias magnetic field coil. It is possible to scan the surface of a structure on an embedded iron material of an embedded concrete structure and diagnose the degree of deterioration along the longitudinal direction of the iron material. Diagnostic method. 3. An iron-based material-embedded concrete structure according to claim 1, wherein a sensor having a multidimensional magneto-impedance effect element in which a plurality of magneto-impedance effect elements are combined with different axial directions is used. Of iron-based materials. The iron-based material of an iron-based material-embedded concrete structure according to any one of claims 1 to 3, wherein one-dimensional to multi-dimensional magneto-impedance effect elements are juxtaposed and the detection output of these elements is multi-channeled Diagnosis method. 5. A method for diagnosing an iron-based material in an iron-based material-embedded concrete structure according to any one of claims 1 to 4, further comprising a transmission means for wirelessly transmitting a detection signal of each channel to a spatially separated place. .

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