Sealant deterioration detection method and deterioration detection system

Abstract

To provide a sealant deterioration detection method capable of detecting deterioration of a sealant arranged inside of an outer wall, even when a decorative material in which multiple tiles are arranged is provided on a wall substrate of the outer wall surface.SOLUTION: A deterioration detection method for detecting deterioration of a sealant 22 comprises: a step for radiating a wave B to a sealant 22 from a surface of a decorative material 30, and on the basis of a reflection wave C reflected on the sealant 22, and setting the frequency of the wave B at which a component of the reflection wave C varied according to a change of hardness of the sealant 22 can be detected; a step for radiating the wave B in the set frequency to the sealant 22 from the surface of the decorative material 30 and receiving the reflection wave C reflected on the sealant 22; and a step for determining deterioration of the sealant 22 on the basis of the reflection wave C.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a deterioration detection method and deterioration detection system for detecting deterioration of a sealant in an exterior wall having an exterior wall base material in which a sealant is placed between siding boards that constitute the exterior wall of a building, and a decorative material in which a plurality of tiles are arranged on the exterior wall base material. [Background technology]

[0002] Traditionally, sealants have been placed between the siding boards that make up the exterior walls of buildings to prevent rainwater and other elements from penetrating inside the walls. The sealants harden when exposed to heat or ultraviolet light, and their ability to conform to the deformation and contraction / expansion of the exterior walls decreases, leading to a deterioration process that can lead to cracks and breaks. As deterioration progresses, rainwater can seep into the walls, causing leaks and expanding the area of ​​deterioration, so it is common to detect deterioration early and perform maintenance (replacement).

[0003] Normally, deterioration of sealants can be diagnosed by visually checking for cracks or breaks, but at this stage the sealant has already reached the end of its life and the damage may have spread due to rainwater seepage, so this is not an effective way to detect the deterioration at an early stage.

[0004] On the other hand, when considering the deterioration process, it is possible to investigate the degree of deterioration from the hardness of the sealant, and a method has been proposed in which a durometer (rubber hardness tester) is used to determine the degree of deterioration by the depth to which a needle is pressed into the sealant.

[0005] For example, Patent Document 1 discloses a method for detecting deterioration of a sealant by inserting a measuring needle into the sealant and determining the deterioration of the sealant from the load acting on the measuring needle. In addition, Patent Document 2 discloses a technology for diagnosing deterioration inside an exterior wall material using electromagnetic waves. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-129004 A [Patent Document 2] JP 2020-183919 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology shown in Patent Document 1 determines deterioration by contacting a measuring needle with the sealant, so for example, if a decorative material consisting of multiple tiles is laid on the exterior surface of an exterior wall, the sealant is not exposed from the exterior wall, and so the sealant cannot be brought into contact with the measuring needle.

[0008] For this reason, even if the technology shown in Patent Document 2 is used, it is possible to detect deterioration such as corrosion of the wood inside the exterior wall by detecting moisture in the exterior wall material from reflected electromagnetic waves, but it is not possible to detect deterioration of the sealing material.

[0009] The present invention has been made in consideration of such problems, and its object is to provide a sealant deterioration detection method and deterioration detection system that can detect deterioration of a sealant placed inside an exterior wall, even if the exterior wall is covered with a decorative material consisting of an arrangement of multiple tiles. [Means for solving the problem]

[0010] As a result of intensive research, the inventors have found that when a sealant deteriorates, its hardness changes, and that the changing hardness of the sealant correlates with the component of the reflected wave of the electromagnetic wave irradiated to the sealant. Since the decorative material on which tiles are arranged has a different molecular structure from the sealant and also has different mechanical properties such as hardness, the inventors have found that if the electromagnetic wave to be irradiated is specified, the electromagnetic wave of the specified frequency can be transmitted through the decorative material and reflected by the sealant. In addition, the reflected wave (electromagnetic wave) reflected by the sealant has a component that reflects at a specified frequency, so the reflected wave also penetrates the decorative material, and the deterioration of the sealant can be detected from the component of the reflected wave.

[0011] The present invention is based on new findings by the inventors, and the method for detecting deterioration of a sealant according to the present invention is a deterioration detection method for detecting deterioration of a sealant in an exterior wall having an exterior wall base material in which a sealant is arranged between siding boards that constitute the exterior wall of a building, and a decorative material in which a plurality of tiles are arranged on the exterior wall base material, and is characterized in that it comprises a frequency setting process of irradiating electromagnetic waves from the surface of the decorative material to the sealant, and setting a frequency of the electromagnetic waves at which a component of the reflected wave that changes in accordance with changes in hardness of the sealant can be detected from the reflected wave reflected by the sealant, an irradiation and reception process of irradiating the electromagnetic wave of the set frequency from the surface of the decorative material to the sealant and receiving the reflected wave reflected by the sealant, and a deterioration determination process of determining deterioration of the sealant based on the component of the reflected wave.

[0012] According to the present invention, in the frequency setting step, when electromagnetic waves of the set frequency are irradiated onto the sealant from the surface of the decorative material, the electromagnetic waves pass through the decorative material and are reflected by the sealant. The electromagnetic waves reflected by the sealant (reflected waves) contain a waveform of the set frequency, and therefore can pass through the decorative material and be received. The reflected waves received in this manner contain components according to the hardness of the sealant, and therefore deterioration of the sealant can be determined based on the components of the reflected waves. As a result, even if a decorative material in which multiple tiles are arranged is provided on an exterior wall base material, deterioration of the sealant arranged inside the exterior wall can be detected.

[0013] In a more preferred embodiment, the component of the reflected wave is either an amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave at the set frequency, or a phase difference of the reflected wave to the electromagnetic wave at the set frequency.

[0014] According to this embodiment, both the amplitude ratio and the phase difference of the reflected waves change according to the change in hardness of the sealant, so that deterioration inside the exterior wall material can be detected by using either the amplitude ratio or the phase difference of the reflected waves.

[0015] In a more preferred embodiment, the component of the reflected wave is either a real part or an imaginary part obtained by complex transforming the amplitude ratio and the phase difference.

[0016] According to this aspect, the components of the reflected wave are either the real part or the imaginary part obtained by complex transforming the amplitude ratio and the phase difference, and the data on these real and imaginary parts contains information on both the amplitude ratio and the phase difference, making it possible to more accurately identify deterioration of the sealing material.

[0017] In a more preferred embodiment, in the irradiation and receiving process, the electromagnetic waves are irradiated along the longitudinal direction of the sealing material while the reflected waves are received at multiple positions along the longitudinal direction of the sealing material, and in the deterioration determination process, deterioration of the sealing material is determined from the components of the multiple reflected waves received at the multiple positions.

[0018] According to this aspect, deterioration of the sealing material can be determined from the components of the reflected waves received at multiple positions along the longitudinal direction of the sealing material, so that even if there is variation in the components of the reflected waves due to measurement errors, etc., the variation can be smoothed out. This makes it possible to accurately determine the deterioration of the sealing material.

[0019] The sealant deterioration detection system of the present invention is a deterioration detection system that detects deterioration of a sealant in an exterior wall having an exterior wall base material in which a sealant is placed between siding boards that constitute the exterior wall of a building, and a decorative material in which a plurality of tiles are arranged on the exterior wall base material, and the deterioration detection system is an irradiation receiving device that irradiates electromagnetic waves from the surface of the decorative material to the sealant and receives the reflected waves reflected by the sealant, and is equipped with an irradiation receiving device in which a frequency of the electromagnetic waves is set that enables detection of the components of the reflected waves that change in accordance with changes in hardness of the sealant, and a arithmetic device that performs calculations to detect deterioration of the sealant, and the arithmetic device judges the deterioration of the sealant based on the components of the reflected waves of the sealant received from the irradiation receiving device.

[0020] According to the present invention, when the irradiation receiving device irradiates electromagnetic waves of a set frequency from the surface of the decorative material to the sealant, the electromagnetic waves pass through the decorative material and are reflected by the sealant. The electromagnetic waves reflected by the sealant (reflected waves) contain a waveform of the set frequency, and therefore can pass through the decorative material and be received. The reflected waves received in this way contain components according to the hardness of the sealant, and the arithmetic device can determine the deterioration of the sealant based on the components of the reflected waves. As a result, even if a decorative material in which multiple tiles are arranged is provided on the exterior wall base material, deterioration of the sealant arranged inside the exterior wall can be detected. Effect of the Invention

[0021] According to the present invention, even if a decorative material consisting of an arrangement of multiple tiles is provided on an exterior wall base material, deterioration of the sealing material arranged inside the exterior wall can be detected. [Brief description of the drawings]

[0022] [Figure 1] The embodiment of the present invention is a schematic perspective view for explaining the relationship between an exterior wall including a sealing material that is a target for deterioration detection and an irradiation receiving device of a deterioration detection system. [Diagram 2] (a) is a schematic diagram showing the deterioration detection system of this embodiment and a cross-section of an exterior wall along the vertical direction, and (b) is a schematic diagram showing the deterioration detection system of this embodiment and a cross-section of an exterior wall along the vertical direction. [Diagram 3] 1 is a diagram for explaining a complex transformation performed by a calculation device of the deterioration detection system. [Figure 4] 3 is a flow diagram of a detection method using the deterioration detection system shown in FIG. 2. [Diagram 5] FIG. 2 is a diagram for explaining a deterioration detection method according to the first to third embodiments. [Figure 6] 13(a) and 13(b) are graphs showing the deterioration detection results according to Examples 1 to 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, a deterioration detection method and a deterioration detection system for detecting deterioration of a sealing material will be described with reference to FIGS. 1 to 6. FIG.

[0024] 1. Regarding exterior wall 20 As shown in FIG. 1, in this embodiment, the deterioration detection system 10 detects deterioration of a sealant 22 arranged between siding boards 21, 21 that form the surface of an exterior wall base material 20A of an exterior wall 20 of a building from the reflected waves of electromagnetic waves irradiated to the exterior wall 20.

[0025] In the embodiment, the exterior wall 20 is a member corresponding to the exterior wall of the building to be inspected. The exterior wall 20 includes an exterior wall base material 20A and a decorative material 30 laid on the exterior wall base material 20A. In the present embodiment, the building is a wooden house or a steel frame house, and the exterior wall base material 20A has a structure of the exterior wall 20 of the building in which a plurality of siding boards 21, 21 are provided on the exterior side and a gypsum board 28 is provided on the interior side.

[0026] Examples of the siding board 21 include ceramic siding boards formed into a board shape using cementitious and fibrous raw materials as main raw materials, and metal siding boards processed from metal materials. The ceramic siding boards may be any of wood fiber reinforced cement boards, fiber reinforced cement boards, and fiber reinforced cement-calcium silicate boards.

[0027] The sealant 22 may be either a fixed sealant or an amorphous sealant, and the material may be a resin material that utilizes mixed reaction hardening or moisture hardening, such as a silicone-based, modified silicone-based, polysulfide-based, acrylic urethane-based, or polyurethane-based material, or a material that utilizes dry hardening, such as an acrylic-based, SBR-based, or butyl rubber-based material, and is not particularly limited as long as the hardness of the sealant 22 changes due to deterioration.

[0028] A sealant 22 is filled between the siding boards 21, 21 that form the exterior wall surface of the exterior wall 20. For example, a wood board may be provided as structural plywood between the siding board 21 and the gypsum board 28. In this embodiment, vertical furring strips 24 and studs 25 are disposed between the siding board 21 and the gypsum board 28.

[0029] Between the siding board 21 and the gypsum board 28, a fireproof material (fiber-based fireproof material) 26 such as glass wool is arranged, and a heat insulating board made of a foamed resin board such as polystyrene foam may be arranged. On the back surface of the sealing material 22, a heat insulating material 24A made of foamed resin is arranged, and on both sides of the heat insulating material 24A, a pair of holding materials 24B, 24B made of polystyrene resin may be arranged to sandwich the foamed resin material that holds the heat insulating material 24A. A ventilation layer may be formed between the siding board 21 and the fireproof material 26. A joint joiner made of metal or resin that joins the siding boards 21, 21 together may be arranged on the back surface of the sealing material 22. In addition, instead of the heat insulating material 24A and the holding material 24B, as shown in FIG. 5, a metal plate 23A, a resin plate 29B, or a wooden plywood 29C may be arranged on the back surface of the sealing material 22.

[0030] A joint tape (butyl tape) 33 made of, for example, butyl rubber is attached along the sealant 22 to cover the sealing material 22 on the opposing edges of the siding boards 21, 21. The joint tape 33 can absorb displacement of the siding boards 21, 21. Mesh members 34, 34 are arranged on both sides of the joint tape 33 along the surface of the sealant 22, and a curing adhesive is applied to the mesh members 34, 34.

[0031] In this embodiment, the mesh members 34, 34 are arranged to sandwich the joint tape 33, but instead of the joint tape 33, the sealant 22 may be covered with the mesh member 34 as long as the decorative material 30 described later can be stably arranged on the exterior wall base material 20A via the mesh member 34. The decorative material 30 is an exterior material in which a plurality of tiles 31 are arranged on the exterior wall base material 20A. Mortar or the like is filled between the tiles 31. The tiles 31 are formed bodies whose main raw material is natural clay or minerals. The decorative material 30 is attached to the exterior wall base material 20A via an adhesive applied to the mesh member 34.

[0032] 2. Hardware of the Deterioration Detection System 10 The deterioration detection system 10 includes an irradiation receiving device 3 that performs non-destructive testing of the sealing material 22 of the exterior wall 20 described above using electromagnetic waves B. As shown in Fig. 1, the irradiation receiving device 3 irradiates electromagnetic waves B of a frequency with a certain amplitude from the surface of the decorative material 30 toward the inside of the exterior wall 20, and receives reflected waves C reflected by the exterior wall 20.

[0033] The irradiation receiving device 3 includes a housing 15. A handle 17 that an operator holds is provided on one side of the housing 15. Wheels 13 are provided on the other side of the housing 15 at a position facing an outer wall 20, which is an object to be inspected. A transmitter 11 and a receiver 12 are disposed inside the housing 15.

[0034] The transmitter 11 is a device that irradiates electromagnetic waves B to the exterior wall 20. The transmitter 11 is set to emit electromagnetic waves B having a predetermined amplitude and a constant frequency. The transmitter 11 irradiates the electromagnetic waves B in accordance with the rotation speed of the wheels 13. This allows the irradiation receiving device 3 (transmitter 11) to irradiate the electromagnetic waves B at constant intervals along the wall surface of the exterior wall 20 (decorative material 30) described below.

[0035] In this embodiment, as shown in FIG. 2, the electromagnetic wave B emitted from the transmitter 11 is a microwave. The frequency of the electromagnetic wave B is a frequency at which the electromagnetic wave B is irradiated from the surface of the decorative material 30 to the sealant 22, and the component of the reflected wave C reflected by the sealant 22, which changes according to the change in hardness of the sealant 22, can be detected. The frequencies of the electromagnetic waves B are set as shown below. First, a test specimen of an exterior wall to be measured or a test specimen of an exterior wall similar thereto, which is equipped with a sealant having deteriorated and undeteriorated parts, is prepared in advance. The test specimen is irradiated with the electromagnetic wave while changing the frequency stepwise so that a component of the reflected wave that can distinguish the difference between the deteriorated and undeteriorated parts can be detected. In this way, the frequency of the electromagnetic wave for detecting deterioration is set.

[0036] For example, these frequencies are not particularly limited as long as it is possible to detect the component of the reflected wave C that changes in accordance with the change in hardness of the sealant 22 from the component of the reflected wave C that has passed through the decorative material 30 and been reflected by the sealant 22. The range of frequencies that pass through a decorative material in which general tiles are arranged, which is generally used as the exterior wall 20, and are reflected by the sealant 22 that is generally used as the exterior wall 20, is 7.0 GHz to 9.0 GHz, and it is preferable to set a frequency within this range, and in particular, it is more preferable to set a frequency within the range of 7.6 GHz to 8.4 GHz (i.e., 8.0±0.4 GHz).

[0037] The receiver 12 is a device that receives a reflected wave C of the electromagnetic wave B transmitted from the transmitter 11 and reflected by the exterior wall 20 (specifically, the sealing material 22). Here, the electromagnetic wave B transmitted (irradiated) by the transmitter 11 is either reflected by the surface of the decorative material 30 or reflected by the sealing material 22 after being refracted, attenuated, and transmitted inside the decorative material 30 or the like. The frequency of the electromagnetic wave B that is set is a wave that the receiver 12 receives as the reflected wave C that is a physical interference between these reflected waves. However, since the frequency of the electromagnetic wave B is set to be difficult to be reflected or attenuated by the decorative material 30 or the like and easy to be reflected by the sealing material 22, the component of the received reflected wave C includes information on the hardness of the sealing material 22 (i.e., deterioration of the sealing material 22). The received reflected wave C is recorded in a storage device (not shown) provided in the housing 15 or a storage device (not shown) provided together with the computing device 4.

[0038] The deterioration detection system 10 includes a calculation device 4 that performs calculations for detecting deterioration of the sealing material 22, and a display device 5 that displays the results of the calculations performed by the calculation device 4. In this embodiment, the calculation device 4 and the display device 5 are provided separately from the irradiation receiving device 3, but may be provided integrally with the irradiation receiving device 3.

[0039] 3. About the arithmetic unit 4 As shown in Fig. 2(a) and (b), the calculation device 4 judges the deterioration of the sealing material 22 based on the components of the reflected wave C. The calculation device 4 calculates the amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave B at a frequency, and the phase difference of the reflected wave C to the electromagnetic wave B at each frequency. Here, since the reflected wave C is a waveform in which a plurality of frequencies are synthesized, the calculation device 4 may identify the frequency that is the main component of the reflected wave C (i.e., the frequency with the highest spectrum (largest amplitude)) by frequency analysis using FFT or the like, and calculate the amplitude ratio L and phase difference P from the amplitude and phase of the reflected wave C at the identified frequency. As another method, the reflected wave C may be directly received, the peak of the received waveform may be used as the amplitude, and the phase of the peak period may be obtained, and the amplitude ratio L and phase difference P may be calculated from these amplitudes and phases.

[0040] Here, the component of the reflected wave C used to determine the deterioration of the sealing material 22 may be either the amplitude ratio L of the reflected wave C to the amplitude of the electromagnetic wave B at the set frequency, or the phase difference P of the reflected wave C to the electromagnetic wave B at the set frequency. That is, the threshold value of the amplitude ratio or phase difference that is the criterion for the presence or absence of deterioration of the sealing material 22 is set together with the frequency of the electromagnetic wave B from the above-mentioned experiment.

[0041] The calculation device 4 judges the deterioration of the sealing material 22 by comparing the magnitude of the calculated amplitude ratio L or phase difference P of the reflected wave C with these thresholds. Note that, from the inventor's experiments, both the calculated amplitude ratio L and phase difference P of the reflected wave C change with the deterioration of the sealing material 22 (with the change in hardness of the sealing material 22). In this case, by comparing the magnitude of one of the amplitude ratio L and phase difference P of the reflected wave C with the corresponding threshold, the deterioration of the sealing material 22 can be detected with high accuracy.

[0042] In addition, the deterioration of the sealing material 22 may be judged based on the amplitude ratio L and phase difference P of the reflected wave C and their corresponding threshold values, and if it is judged that the sealing material 22 has deteriorated based on either one of the judgment results, it may be judged that the sealing material 22 has deteriorated.

[0043] Here, the component of the reflected wave C used to determine the deterioration of the sealing material 22 may be either the real part R or the imaginary part K obtained by complex transforming the amplitude ratio L and the phase difference P. The calculation device 4 performs complex transform on the amplitude ratio L and the phase difference P to calculate the real part R and the imaginary part K. Specifically, as shown in FIG. 3, a point T corresponding to the amplitude ratio L and the phase difference P is plotted on a complex plane, and the values ​​of the real part R and the imaginary part K on the real axis and the imaginary axis are calculated. In this case as well, the threshold value of the real part R or the imaginary part K, which is a criterion for the presence or absence of deterioration of the sealing material 22, is set together with the frequency of the electromagnetic wave B from the above-mentioned experiment.

[0044] The arithmetic unit 4 judges the deterioration of the sealing material 22 by comparing the magnitude of the calculated complex-converted real part R and imaginary part K with these thresholds. The inventor's experiments have shown that both the complex-converted real part R and imaginary part K change with the deterioration of the sealing material 22 (with the change in hardness of the sealing material 22). Therefore, by comparing the magnitude of one of the complex-converted real part R and imaginary part K with the corresponding threshold, the deterioration of the sealing material 22 can be detected with high accuracy. In this embodiment, the complex-converted real part R and imaginary part K are identification data on the same complex plane, so that the deterioration of the sealing material 22 can be identified with high accuracy.

[0045] In addition, the deterioration of the sealing material 22 may be judged based on the real part R, the imaginary part K, and their corresponding threshold values, and if it is determined that the sealing material 22 has deteriorated based on either one of the judgment results, it may be determined that the sealing material 22 has deteriorated.

[0046] When the irradiation receiving device 3 scans along the position of the sealing material 22, it is possible to receive reflected waves C at a plurality of positions along the longitudinal direction of the sealing material 22 while irradiating electromagnetic waves B along the longitudinal direction of the sealing material 22. At this time, the calculation device 4 may determine the deterioration of the sealing material 22 from the components of the plurality of reflected waves C received at the plurality of positions.

[0047] Specifically, the calculation device 4 may calculate an average value of data used to determine deterioration (amplitude ratio L, phase difference P, real part R, or imaginary part K) at multiple positions calculated from the reflected wave C, and determine deterioration by comparing this average value with a threshold value (the threshold value mentioned above) set for this data.

[0048] As a result, the deterioration of the sealing material 22 can be determined from the components of the reflected wave C received at a plurality of positions along the longitudinal direction of the sealing material 22. Therefore, even if there is variation in the components of the reflected wave C due to measurement errors or the like, the variation can be smoothed out. As a result, the deterioration of the sealing material 22 can be determined with high accuracy.

[0049] A method for determining the deterioration of the sealing material 22 will be described below with reference to the flow chart of FIG. In step S11, the frequency of the electromagnetic waves to be irradiated to the exterior wall 20 is set. First, a test specimen corresponding to the exterior wall 20 is prepared. Specifically, as the sealant 22 provided inside the test specimen (exterior wall 20), a sealant 22 having a deteriorated portion and a non-deteriorated portion is arranged between the siding boards 21, 21 along the longitudinal direction. Here, the deteriorated state of the deteriorated portion of the sealant 22 is in the early stage of deterioration as the sealant 22, where its function is impaired and repair is required.

[0050] Next, in a control device (not shown) of the irradiation receiving device 3, electromagnetic waves B of multiple frequencies are irradiated from the surface of the decorative material 30 of the test specimen corresponding to the exterior wall 20, and reflected waves C are received for each frequency. At this time, among the electromagnetic waves B of multiple frequencies, a frequency of the electromagnetic waves B that provides a component of the reflected waves C that changes in accordance with the change in hardness of the sealant 22 is selected, and this frequency is set. That is, the components of the reflected waves C described above are calculated for each frequency, and a frequency at which a clear difference is made between the deteriorated and non-deteriorated parts of the sealant 22 is selected from the calculated components, and this is set as the frequency of the electromagnetic waves B to be irradiated.

[0051] At this time, in order to distinguish between the components of the reflected wave C from the deteriorated parts of the selected sealing material 22 and the components of the reflected wave C from the non-deteriorated parts of the sealing material 22, threshold values ​​(the threshold values ​​mentioned above) for these are also set.

[0052] Next, in step S12, an irradiation and reception process is performed. Specifically, electromagnetic waves are irradiated to the exterior wall 20 and the reflected waves are received. Specifically, as shown in Fig. 1, electromagnetic waves B having a set constant amplitude and constant frequency are irradiated from the decorative material 30 of the exterior wall 20 toward the inside of the exterior wall 20, and reflected waves C reflected by the exterior wall 20 (specifically, the sealing material 22) are received.

[0053] Specifically, while irradiating electromagnetic waves B along the longitudinal direction of the sealing material 22, reflected waves C are received at a plurality of positions along the longitudinal direction of the sealing material 22. More specifically, the following operations are performed. In this embodiment, since the sealing material 22 is not exposed, the position of the sealing material 22 is identified from a design drawing of the exterior wall 20 or the like. Next, while holding the handle 17 of the irradiation receiving device 3 shown in FIG. 1, the wheels 13 of the irradiation receiving device 3 are pressed against the surface of the decorative material 30. Next, while rotating the wheels 13 on the outer wall surface of the decorative material 30, the irradiation of electromagnetic waves B and reception of reflected waves C are performed by moving (scanning) the irradiation receiving device 3 in the vertical direction (or horizontal direction) along the sealing material 22.

[0054] In step S13, the calculation device 4 calculates the amplitude ratio L of the reflected wave C received at each position along the longitudinal direction of the sealing material 22 and the phase difference P of the reflected wave C with respect to the electromagnetic wave B.

[0055] In step S14, the calculation device 4 performs complex transformation on the amplitude ratio L and phase difference P calculated for each position along the longitudinal direction of the sealing material 22 to a real part R and an imaginary part K. Note that, when the sealing material 22 is judged using the amplitude ratio L or phase difference P of the reflected wave C, step S14 is omitted.

[0056] Finally, in step S15, the calculation device 4 determines the deterioration of the sealing material 22 based on the components of the reflected waves (real part R or imaginary part K). Specifically, the calculation device 4 determines the deterioration of the sealing material 22 from the components of the multiple reflected waves C received at multiple positions of the sealing material 22. The judgment of the sealing material 22 is made by the calculation device 4 as described above.

[0057] According to this embodiment, when the electromagnetic wave B of the set frequency is irradiated from the surface of the decorative material 30 to the sealant 22, the electromagnetic wave B passes through the decorative material 30 and is reflected by the sealant 22. The electromagnetic wave reflected by the sealant 22 (reflected wave C) contains a waveform of the set frequency, and therefore passes through the decorative material 30 and can be received. The reflected wave C received in this manner contains a component corresponding to the hardness of the sealant 22, and therefore deterioration of the sealant 22 can be determined based on the component of the reflected wave C. As a result, even if the decorative material 30 in which a plurality of tiles are arranged is provided on the surface of the exterior wall base material 20A, deterioration of the sealant 22 arranged inside the exterior wall 20 can be accurately detected regardless of the surface shape, material, etc. of the decorative material 30.

[0058] The inventors prepared a specimen of an exterior wall 20 on which a sealant 22 with only the upper half degraded was placed. The specimens of Examples 1 to 3 differ in that a metal plate 23A, a resin plate (polystyrene plate) 29B, or a plywood 29C was placed on the back surface of a pair of siding boards 21, 21 and the sealant 22.

[0059] For these, in a series of step S11 shown in Fig. 4, the frequency of the electromagnetic wave was set to 8.0 GHz, and in steps S12 to 13, electromagnetic wave B was irradiated at equal intervals along the longitudinal direction of sealant 22 for each test piece, and the values ​​of phase difference P and imaginary part K (imaginary part data) of reflected wave C obtained in this way were calculated for each position along the longitudinal direction of sealant 22. Note that in Figs. 6(a) and (b), positions 1 to 13 shown on the horizontal axis are positions where deteriorated hard sealant 22 exists, and positions 14 to 27 are positions where undeteriorated soft sealant 22 exists.

[0060] 6(a), for each of the specimens in Examples 1 to 3, the phase difference values ​​at positions 1 to 13 tend to be lower than the phase difference values ​​at positions 14 to 27. Therefore, in order to detect deterioration of the sealing material 22, the threshold value for deterioration determination is set to 0.9 rad, and if the phase difference is smaller than this, it can be determined that the sealing material 22 has deteriorated.

[0061] However, even in such a case, since the phase difference at position 8 in Example 3 is about 1.0 rad due to a measurement error caused by a disturbance, etc., it may be determined that the sealing material 22 is not deteriorated. Similarly, since the phase difference at position 23 in Example 3 is slightly smaller than 0.9 rad due to a measurement error caused by a disturbance, etc., it may be determined that the sealing material 22 is deteriorated. Even in such a case, since the phase difference is measured at successive positions along the longitudinal direction of the sealing material 22, other phase differences can be confirmed and erroneous detection of the sealing material due to a measurement error, etc. can be avoided.

[0062] Similarly, as is clear from the results of FIG. 6(b), for each of the specimens in Examples 1 to 3, the values ​​of the imaginary part data at positions 1 to 13 tend to be lower than the values ​​of the imaginary part data at positions 14 to 27. In particular, in the case of Example 1, it is considered that the resolution for detecting deterioration of the sealant is improved by using the imaginary part data. However, in the case of Example 2, since there is variation in the data due to the influence of measurement errors, for example, in the case of Example 2, when detecting whether the sealant is generally deteriorated or not, if the average value of the imaginary part data at multiple positions is 3000 or less, it may be determined that the sealant is deteriorated, and if the average value exceeds 3000, it may be determined that the sealant is not deteriorated. Although not illustrated, it was recognized that there was a difference between a deteriorated sealant and a non-deteriorated sealant even when the amplitude ratio and real part data were used, although the difference was not as clear as when the phase difference and imaginary part data were used.

[0063] As described above, according to this embodiment, the use of electromagnetic waves in the microwave region provides high safety. Furthermore, since the deterioration (degree of deterioration) of the sealant can be detected, maintenance can be performed at an appropriate time. Furthermore, if the device is mounted on an unmanned aerial vehicle such as a drone, deterioration of the sealant at high places can be detected safely and quickly.

[0064] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0065] 3: irradiation receiving device, 4: calculation device, 10: deterioration detection system, 20: exterior wall, 21: siding board, 22: sealing material, 30: decorative material, 31: tile, B: electromagnetic wave, C: reflected wave, F: frequency, L: amplitude ratio, P: phase difference, R: real part, K: imaginary part

Claims

1. A deterioration detection method for detecting deterioration of a sealant in an exterior wall having an exterior wall base material in which a sealant is disposed between siding boards constituting the exterior wall of a building, and a decorative material in which a plurality of tiles are arranged on the exterior wall base material, comprising: a frequency setting step of irradiating electromagnetic waves onto the sealant from the surface of the decorative material, and setting a frequency of the electromagnetic waves such that a component of the reflected wave that changes in response to a change in hardness of the sealant can be detected from the reflected wave reflected by the sealant; an irradiation and reception step of irradiating the electromagnetic wave having the set frequency from a surface of the decorative material to the sealing material and receiving the reflected wave reflected by the sealing material; A deterioration detection method for a sealant on an exterior wall of a building, comprising: a deterioration determination step of determining deterioration of the sealant based on the component of the reflected wave.

2. The method for detecting deterioration of a sealing material as described in claim 1, characterized in that the component of the reflected wave is either an amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave at the set frequency, or a phase difference of the reflected wave to the electromagnetic wave at the set frequency.

3. 3. The method for detecting deterioration of a sealing material according to claim 2, wherein the component of the reflected wave is either a real part or an imaginary part obtained by complex transforming the amplitude ratio and the phase difference.

4. In the irradiation and reception step, the electromagnetic wave is irradiated along a longitudinal direction of the sealing material, while the reflected wave is received at a plurality of positions along the longitudinal direction of the sealing material; 2. The method for detecting deterioration of a sealing material according to claim 1, wherein in the deterioration determining step, deterioration of the sealing material is determined from a plurality of components of the reflected waves received at the plurality of positions.

5. A deterioration detection system for detecting deterioration of a sealant in an exterior wall having an exterior wall base material in which a sealant is disposed between siding boards constituting the exterior wall of a building, and a decorative material in which a plurality of tiles are arranged on the exterior wall base material, comprising: The deterioration detection system includes an irradiation receiving device that irradiates electromagnetic waves from the surface of the decorative material to the sealant and receives the reflected waves reflected by the sealant, the irradiation receiving device being set to a frequency of the electromagnetic waves that allows detection of components of the reflected waves that change in accordance with changes in hardness of the sealant; A calculation device that performs a calculation to detect deterioration of the sealing material, The sealing material deterioration detection system is characterized in that the calculation device determines deterioration of the sealing material based on the component of the reflected wave of the sealing material received from the irradiation receiving device.

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