WO2020079866A1 - Chloride ion sensor and chloride ion concentration measurement method - Google Patents

Abstract

The present invention aims to provide a chloride ion sensor capable of long-term monitoring and a chloride ion concentration measurement method. This chloride ion sensor measures the chloride ion concentration in a concrete structure and comprises: at least one pair of electrodes arranged, spaced apart, on the surface of the concrete structure; and a measurement unit that measures impedance in a state in which an AC current is flowing between the at least one pair of electrodes. The at least one pair of electrodes has a hot-melt electrode including a hot-melt resin having a conductive filler dispersed therein.

Description

Chloride ion sensor and chloride ion concentration measuring method

The present invention relates to a chloride ion sensor for detecting chloride ions in a concrete structure, and a chloride ion concentration measuring method.

Deterioration of metal such as reinforcing bars placed in a concrete structure may be accelerated depending on the surrounding environment. For example, it is known that corrosion of the metal is easily promoted in an environment with a high chloride ion concentration. Therefore, a method of nondestructively measuring the chloride ion concentration in the concrete structure is being studied.

The conductive method is known as one of the methods for measuring the concentration of chloride ions in concrete structures. The conductive method is to be summarized, in a state where an alternating current is applied to the target concrete structure, the impedance of the concrete structure and the phase angle peak frequency of the impedance are measured, and the moisture content of the concrete structure is measured. This is a method of calculating the chloride ion concentration in combination with the information of.

Various measuring devices and measuring systems used for the above-mentioned conductive method have been proposed.
For example, in Patent Document 1, a characteristic information storage unit that stores information about the characteristics of a concrete body, a pair of electrodes that are arranged on the surface of the concrete body at intervals, and the pair of electrodes are disposed between the pair of electrodes. A measuring means for measuring impedance or peak frequency in a state where an alternating current is passed through a concrete body, based on a measured value such as impedance measured using the measuring means, referring to the characteristic information, salinity A system for measuring the salinity of a concrete body for identifying the concentration is disclosed. The characteristic information includes, for example, characteristic information that correlates the impedance, the peak frequency of the impedance, the moisture content, and the salt concentration with each other. According to Patent Document 1, it is said that the system described above makes it possible to easily and in real time measure the salt concentration of a concrete body while visiting a building to be measured.

Further, in Patent Document 2, a pair of electrodes arranged on the surface of the concrete body at a distance from each other, and an impedance in a state in which an alternating current is passed between the pair of electrodes via the concrete body, Measuring means for measuring the phase angle peak frequency at which the phase angle of the impedance becomes a peak, water content of the concrete body, or water content information acquiring means for acquiring the amount of water vapor in the environment in which the concrete body is arranged, Based on the impedance and the phase angle peak frequency measured by measuring means, based on the plurality of water content or a plurality of water vapor content obtained by the moisture information acquisition means, the chloride concentration of the concrete body Based on the evaluation value calculated by the calculating means for calculating an evaluation value for evaluation and the calculating means, the concrete And a specifying means for specifying a product concentration, chloride concentration measurement system is disclosed in the concrete body. According to Patent Document 2, regarding the impedance and the phase angle peak frequency that are easily affected by external factors such as the amount of water vapor, the chloride concentration of the concrete body is accurately measured by considering the influence of the external factors. It is supposed to be possible.
In the systems of Patent Documents 1 and 2, brass is used as the electrode.

JP 2012-184948 A Patent No. 6338238

Long-term monitoring of chloride ion concentration is necessary to estimate the state of metals such as reinforcing bars placed in concrete structures. The present inventors considered installing a chloride ion sensor in a concrete structure and performing long-term monitoring at a fixed point. However, there is a problem that the electrodes arranged on the surface of the concrete structure are easily deteriorated by chloride ions in the concrete.

The present invention has been made in view of such circumstances, and an object thereof is to provide a chloride ion sensor capable of long-term monitoring and a chloride ion concentration measuring method.

The present inventors have completed the present invention by finding that the above problems can be solved by using an electrode having excellent weather resistance and excellent adhesion to a concrete surface.

That is, the chloride ion sensor of the present embodiment is a sensor for measuring the chloride ion concentration in the concrete structure,
At least a pair of electrodes spaced apart from each other on the surface of the concrete structure;
A measuring unit for measuring impedance in a state in which an alternating current is applied between the at least one pair of electrodes,
The at least one pair of electrodes has a hot melt electrode containing a hot melt resin in which a conductive filler is dispersed.

In one embodiment of the chloride ion sensor, the conductive filler is silver or conductive carbon.

In one embodiment of the chloride ion sensor, the hot melt resin contains a thermoplastic elastomer.

In one embodiment of the chloride ion sensor, the electrode has a conductive layer on the hot melt electrode.

One embodiment of the chloride ion sensor is
One embodiment of the chloride ion sensor further includes a base material on the electrode.

In one embodiment of the above chloride ion sensor, the electrodes are formed into a sheet.

An embodiment of the above chloride ion sensor has a plurality of the electrodes, and the plurality of electrodes are arranged in a pattern on a sheet-shaped base material.

In one embodiment of the chloride ion sensor, the electrode and the measurement unit are connected by conductive wiring, at least a part of the conductive wiring is a pattern wiring formed on at least one surface of the base material. is there.

The one embodiment of the chloride ion sensor further includes a wireless transmission unit that wirelessly transmits information based on the detected impedance.

In one embodiment of the chloride ion sensor, the wireless transmission unit further includes a battery that supplies electric power.

The chloride ion concentration measuring method of the present embodiment is a measuring method for measuring the chloride ion concentration in the concrete structure,
A preparatory step of preparing the chloride ion sensor,
At least a pair of electrodes provided in the chloride ion sensor, a bonding step for respectively bonding to the surface of the concrete structure,
A measuring step of measuring the impedance in the state of flowing an alternating current through the concrete body between the at least a pair of electrodes,
The adhering step includes a step of adhering to the concrete structure by heating and melting the hot melt electrode.

One embodiment of the chloride ion concentration measuring method further has a calculation step of calculating a chloride ion concentration from the measured impedance,
The calculation step calculates a chloride ion concentration based on at least the measured impedance obtained in the impedance measurement step.

In one embodiment of the chloride ion concentration measuring method, the preparing step is a preparing step of preparing the chloride ion sensor according to claim 7 or 8.
The method further includes the step of wirelessly transmitting information based on the measured impedance obtained by the impedance measuring step.

According to the present invention, it is possible to provide a chloride ion sensor capable of long-term monitoring and a chloride ion concentration measuring method.

It is a schematic diagram of a chloride ion sensor of a 1st embodiment. It is a schematic diagram showing an installation example of a chloride ion sensor. It is a schematic diagram of a chloride ion sensor of a 2nd embodiment. It is a schematic diagram of a chloride ion sensor of a 3rd embodiment. It is a block diagram which shows an example of a calculating part. It is a flow chart which shows an example of a chloride ion concentration measuring method. It is a schematic sectional drawing which shows an example of the electrode 1a. It is a schematic sectional drawing which shows another example of the electrode 1a. It is a schematic front view of the electrode sheet provided with the wiring pattern in 4th Embodiment. FIG. 9B is a side view of FIG. 9A.

[Chloride ion sensor]
The chloride ion sensor of this embodiment is
At least a pair of electrodes spaced apart from each other on the surface of the concrete structure;
A measuring unit for measuring impedance in a state in which an alternating current is applied between the at least one pair of electrodes,
The at least one pair of electrodes has a hot melt electrode containing a hot melt resin in which a conductive filler is dispersed.

The chloride ion sensor of the present embodiment can be installed in a concrete structure for a long period of time (for example, 3 months or more) and has a chloride ion sensor that can be monitored for a long time. can do.
The chloride ion sensor of the present embodiment measures the impedance with at least a pair of electrodes in a state where an alternating current is passed through a concrete structure to be measured. The chloride ion concentration is measured by referring to a concrete characteristic information database (hereinafter, may be referred to as characteristic information DB) of concrete including the relationship between impedance, moisture content, and chloride ion concentration, which has been prepared in advance. It is calculated from the impedance.
Hereinafter, regarding such a chloride ion sensor of the present embodiment, the electrodes will be described first, and then each embodiment will be described with reference to the drawings.

Note that, in the present implementation, the frequency is the frequency corresponding to the impedance, and specifically, the frequency of the alternating current passed through the concrete structure during the impedance measurement. The peak frequency means the frequency at which the phase angle of impedance reaches its peak. The water content means the water content per unit volume in the range from the surface of the concrete structure to a predetermined depth (for example, 20 mm). The amount of water vapor means the amount of water vapor in the environment where the concrete structure is arranged, and can be calculated from the humidity and the temperature by referring to the vapor pressure curve.

<Electrode>
The electrode used in the chloride ion sensor of the present embodiment has at least a hot-melt electrode containing a hot-melt resin in which a conductive filler is dispersed, and if necessary, further has a conductive layer and other components. You can do it. Each configuration of such an electrode will be described below.

(Hot melt electrode)
In the present embodiment, the hot melt electrode is arranged and used on the surface of the concrete structure.
In the present embodiment, the hot melt electrode is one that is melted by heating, attached to the surface of the concrete structure, and then cooled and solidified. Therefore, the concrete structure is firmly held in close contact with the surface. Further, since the hot melt electrode fills the voids on the surface of the concrete structure, the contact resistance is suppressed. Further, since the conductive filler is dispersed in the hot melt resin, it is retained in the electrode without being dissociated from the electrode and penetrating into the concrete structure. Therefore, the hot melt electrode of the present embodiment has a small state change on the surface of the concrete structure, and can stably measure the voltage. Therefore, a chloride ion sensor capable of long-term monitoring can be obtained by using the electrode.

The hot melt electrode of the present embodiment contains at least a hot melt resin and a conductive filler, and may further contain other components as necessary. Hereinafter, each component contained in such a hot melt electrode will be described.

(1) Hot-melt resin In the present embodiment, the hot-melt resin contains a resin that can be heated and melted when the electrode is placed on the surface of the concrete structure, and a known thermoplastic resin should be used as such a resin. You can

Examples of the thermoplastic resin include polyurethane resin, acrylonitrile resin, acrylic resin, polyamide resin, polyvinyl butyral resin, polyester resin, styrene resin, silicone resin, and thermoplastic elastomer. They may be used alone or in combination of two or more.

In this embodiment, it is preferable that the hot melt resin contains a thermoplastic elastomer. By including the thermoplastic elastomer, the electrode having rubber elasticity at room temperature (for example, 25 ° C.) can be obtained. By having rubber elasticity, it is possible to obtain a chloride ion sensor that suppresses electrode breakage and enables long-term monitoring. The elastic modulus of the thermoplastic elastomer at room temperature can be, for example, 0.1 to 100 MPa.

Examples of the thermoplastic elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene. -Styrene-based thermoplastic elastomer such as ethylene / propylene-styrene block copolymer (SEPS); urethane-based thermoplastic elastomer (TPU); olefin-based thermoplastic elastomer (TPO); polyester-based thermoplastic elastomer (TPEE); polyamide-based Examples thereof include thermoplastic elastomers, fluorine-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, and the like, and they can be used alone or in combination of two or more. Further, the thermoplastic elastomer may be hydrogenated.
In the present embodiment, it is preferable to include a styrene-based thermoplastic elastomer among the thermoplastic elastomers.

In the present embodiment, the weight average molecular weight of the hot melt resin is preferably 5,000 or more and 1,000,000 or less, more preferably 10,000 or more and 800,000 or less, from the viewpoint of handleability.
In the present embodiment, the weight average molecular weight is a polystyrene equivalent molecular weight measured by GPC (gel permeation chromatography) “HLC-8320” manufactured by Tosoh Corporation.

From the viewpoint of conductivity and adhesiveness, the content ratio of the hot melt resin is preferably 40 to 98% by mass, and more preferably 60 to 95% by mass in 100% by mass of the total amount of the hot melt electrode.

(2) Conductive Filler In the present embodiment, the conductive filler is used by being dispersed in the hot melt resin to ensure the conductivity of the electrode. The conductive filler can be appropriately selected from known ones. The shape of the conductive filler may be any particle shape that can be dispersed in the hot melt resin, and may be any shape such as flake shape (scaly shape), spherical shape, needle shape, fibrous shape, or dendritic shape. From the viewpoint of ensuring the conductivity while reducing the content ratio of the conductive filler, it is preferable to use the flaky conductive filler.

Examples of the material of the conductive filler include metals such as silver, gold, copper, zinc, zinc oxide, manganese, nickel, and aluminum; tin oxide-doped indium oxide (ITO), tin oxide-doped indium oxide (FTO), tin oxide (IO). ), Metal oxides such as neodymium / barium / indium oxide; organic substances such as polypyrrole, polythiophene, polyaniline, oligothiophene; carbon black, graphite, graphene, graphite, carbon nanotubes, carbon fiber, fullerene, graphene oxide In addition to conductive carbon such as acetylene black, inorganic insulators such as alumina and glass and polymers such as polyethylene and polystyrene whose surface is coated with a conductive material can be used. In the present embodiment, the conductive filler may be used alone or in combination of two or more.

In the present embodiment, among them, the conductive filler is preferably silver or conductive carbon, and more preferably conductive carbon. Further, as the conductive carbon, graphite, carbon fiber, carbon black, carbon nanotube, graphene, or graphene oxide is particularly preferable.
Since silver and conductive carbon have excellent conductivity and various resistances such as heat resistance, water resistance, and acid resistance, the electrode has excellent long-term reliability. In addition, the hot-melt electrode using silver or conductive carbon has a stable presence of the silver or conductive carbon, and long-term monitoring is possible, so it is possible to capture voltage changes without using a reference electrode. You can Therefore, the corrosion sensor can be realized even if the electrode of this embodiment does not have a reference electrode.

From the viewpoint of conductivity and adhesiveness, the content ratio of the conductive filler is preferably 2 to 60 mass% and more preferably 5 to 40 mass% in 100 mass% of the hot melt electrode.
The thickness of the hot melt electrode is not particularly limited, but is, for example, 50 to 2000 μm, preferably 100 to 1500 μm.

(3) Other components The hot melt electrode of the present embodiment may contain other components as long as the effect is not impaired. Suitable other ingredients include tackifiers, plasticizers and the like. Since the hot melt electrode containing the tackifier or the plasticizer is provided with the tackiness, it can be temporarily fixed to the concrete surface and the construction at the time of adhesion becomes easy. The tackifier and the plasticizer may be appropriately selected from known ones and used alone or in combination of two or more kinds. Moreover, the tackifier and the plasticizer may be used alone or in combination.
When the hot-melt electrode contains a tackifier or a plasticizer, the total content ratio thereof is preferably 0.5% by mass or more and 40% by mass or less, and 1% by mass or more and 20% by mass, in 100% by mass of the total amount of the hot-melt electrode. % Or less is more preferable.

Further, the hot melt electrode of the present embodiment, as other components, for example, silane coupling agent, titanate coupling agent, flexibility imparting agent, flame retardant, storage stabilizer, antioxidant, metal deactivating agent. Agents, ultraviolet absorbers, thixotropy imparting agents, leveling agents, defoaming agents, dispersion stabilizers, fluidity imparting agents, defoaming agents, antiblocking agents, flame retardants, coloring materials and the like. When the hot melt electrode contains these components, the content ratio thereof is preferably 5% by mass or less and more preferably 3% by mass or less in 100% by mass of the total amount of the hot melt electrode.

(Other configurations)
In the present embodiment, the electrode may have a structure having only the hot melt electrode, or may have another structure such as a conductive layer, if necessary.

The conductive layer is provided on the surface opposite to the surface of the hot melt electrode on the surface of the concrete structure. Since the conductive layer does not directly contact the surface of the concrete structure, the influence of corrosion due to chloride ions in the concrete structure is suppressed. Therefore, the conductive layer can have any structure. Examples of the conductive layer include a silver / silver chloride electrode layer, a silver / silver chloride electrode layer containing carbon flakes, and a conductive foil such as a metal foil.

Moreover, you may have a base material further on an electrode. The base material is usually arranged on the surface of the hot melt electrode opposite to the surface arranged on the surface of the concrete structure, and when it has the conductive layer, it is arranged on the conductive layer. The base material not only improves handleability during electrode production, but also functions as a protective film for the hot melt electrode and the conductive layer when the electrode is used.
In the present embodiment, the substrate is not limited, and can be appropriately selected from various resin films, for example. Examples of the material of the base material include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polystyrene, polyimide, polyamide, polyether sulfone, polyethylene naphthalate, polybutylene terephthalate, polyvinyl chloride, polyethylene, polypropylene, cycloolefin polymer, ABS ( Acrylonitrile-butadiene-styrene copolymer resin), AES (acrylonitrile-ethylene-styrene copolymer resin), Kydak (acrylic modified vinyl chloride resin), modified polyphenylene ether, and films such as polymer alloys composed of two or more of these resins, These laminated films etc. are mentioned. The substrate may be transparent or opaque. The base material preferably has flexibility because it easily follows the irregularities on the concrete surface.

(Method of manufacturing electrode)
An example of the method of manufacturing the electrode in this embodiment will be described below.
As an example of a method for manufacturing an electrode, first, the hot melt resin, the conductive filler, and other components used as necessary are mixed to form a mixture. The mixture may contain a solvent that dissolves the hot melt resin in order to disperse it uniformly.
Then, the mixture is dispersed by a known disperser to obtain a dispersion. Examples of the disperser include roll mills such as two rolls and three rolls, ball mills such as ball mills and vibrating ball mills, paint conditioners, bead mills such as continuous disc type bead mills and continuous annular bead mills.
Then, the obtained dispersion is applied onto a substrate. The coating method may be appropriately selected depending on the thickness and material of the hot melt electrode. For example, inkjet method, spray method, spin coating method, dip method, roll coating method, blade coating method, doctor roll method, doctor blade method, curtain coating method, slit coating method, screen printing method, reversal printing method, hot melt applicator , Hot melt coater, slit coater, hot melt roll coater and the like. A hot melt electrode can be obtained by drying the obtained coating film as needed.
When the base material is unnecessary, the base material may be peeled off after forming a coating film similar to the above using a peelable base material. When the electrode has a conductive layer, the hot melt electrode may be formed by forming the conductive layer on the substrate and then coating the dispersion for the hot melt electrode on the conductive layer.

-The electrode formed by the above method is made into a sheet. Further, by printing the hot melt electrodes in a pattern by the above method, a plurality of electrodes can be arranged in a pattern on one sheet-shaped base material. By arranging the plurality of electrodes in a pattern, it is not necessary to adjust the distance between the pair of electrodes. Further, by arranging a plurality of electrodes on one sheet-shaped base material, even when a plurality of chloride ion sensors are arranged on a concrete structure, the installation becomes easy.

<Embodiment of chloride ion sensor>
Hereinafter, an embodiment of a chloride ion sensor according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing a first embodiment of the chloride ion sensor of the present embodiment. The chloride ion sensor 10 shown in the example of FIG. 1 includes a pair of electrodes 1a and 1b which are arranged on the surface of a concrete structure 100 at a distance from each other, and a measurement unit 2 which measures impedance. The electrodes 1a and 1b each have a hot melt electrode.
The distance between the electrodes 1a and 1b is an arbitrary distance within a range in which impedance can be measured in the state where an alternating current is applied to the concrete structure 100, and is, for example, 1 to 100 mm. As a tendency, the wider the distance between the pair of electrodes 1a and 1b, the deeper the depth of the concrete structure can be measured. Therefore, the depth can be adjusted according to the depth of the concrete structure 100 to be measured.

Here, the configuration of the electrodes will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic sectional view showing an example of the electrode 1a. The electrode 1a shown in FIG. 7 uses a laminated body in which the conductive layer 5 and the base material 6 are laminated in this order on the hot melt electrode 4, and the configuration of the electrode 1a is at least the hot melt electrode as described above. It suffices if the electrode 4 is provided.
Further, in the example of FIG. 8, the electrode 1 a arranged on the surface of the concrete structure 100 is covered with the protective portion 7. With such a configuration, it is possible to suppress contact between the electrode 1a including the hot-melt electrode 4 and external moisture or salt, and thus a chloride ion sensor having longer-term reliability is obtained. The protection part 7 may seal the entire electrode 1a including the base material 6 as shown in the example of FIG. In addition, the protective portion 7 may be disposed at least at the peripheral portion of the electrode 1a and may protect the electrode 1a in combination with the base material 6. A known resin can be used for the protection part 7. The details of the hot-melt electrode 4, the conductive layer 5, and the base material 6 are as described above, and thus the description thereof is omitted here.

The measuring unit 2 passes an alternating current between at least a pair of electrodes 1a and 1b through the concrete structure 100, and measures the impedance in the state where the alternating current is passed, and further the frequency and the peak frequency as necessary. To do. A known impedance meter (LCR meter) can be used as the measuring unit 2. Further, the measuring unit 2 may be configured by combining an oscillator, an ammeter and the like.
The impedance meter is a measuring unit that measures an impedance or a peak frequency in a state where an alternating current is passed through at least a pair of electrodes 1a and 1b through the concrete structure 100. The measurement principle of this impedance meter is arbitrary, but the impedance can be measured by a known method such as a bridge method or a resonance method. A two-terminal method impedance meter uses a pair of electrodes (two electrodes). Further, in a four-terminal method impedance meter, two pairs of electrodes (four electrodes) are used.
The measurement unit 2 may be normally connected to the calculation unit 50 to form a chloride ion sensor system. In the example of FIG. 1, the measurement unit 2 and the calculation unit 50 are connected by the wiring 21. The impedance and the like measured by the measurement unit 2 are input to the calculation unit 50, and the calculation unit 50 calculates the chloride ion concentration. The calculation unit 50 will be described later.

The concrete structure 100 to be measured in this embodiment is not particularly limited. The concrete structure 100 to be measured usually contains chloride ions and water, and further has a reinforcing bar inside. The structure of the concrete structure 100 is arbitrary and may be a flat surface or a curved surface, and may have irregularities or the like. Since the electrodes 1a and 1b of the chloride ion sensor 10 of the present embodiment have hot melt electrodes, they can be adhered to each other by following an arbitrary shape. Specific examples of the concrete structure 100 include a tunnel, a bridge, a pier, a dam, and other concrete structures forming at least a part of a building.

FIG. 2 shows an example in which the chloride ion sensor 10 of the present embodiment is arranged on the inner wall 101 of the tunnel. One chloride ion sensor 10 of the present embodiment may be arranged alone on the inner wall 101 of the tunnel, or two or more thereof may be connected as shown in the example of FIG. The connected chloride ion sensor 20 can be manufactured, for example, by providing a plurality of measurement units 2 on electrodes arranged in a pattern on a sheet-shaped base material 31. By using the chloride ion sensors 20 connected to each other, it becomes easy to install each chloride ion sensor 10 at predetermined intervals.

Further, as shown in the example of FIG. 2, the connected chloride ion sensor 20 may share the wiring 22. The wiring 22 includes, for example, a wiring that connects the measurement unit 2 and the calculation unit 50, a wiring that connects the measurement unit 2 and a wireless transmission unit 3 described below, each chloride ion sensor 10 and an external power source (not shown). Examples include wiring to be connected. When the connected chloride ion sensor 20 shares the wiring 22, the calculation unit 50 and the wireless transmission unit 3 may be shared.

Further, as shown in the example of FIG. 2, a plurality of connected chloride ion sensors 20 may be provided in the tunnel at predetermined intervals. By providing a plurality of connected chloride ion sensors 20, the chloride ion concentration over the entire tunnel can be mapped.
As shown in the example of FIG. 2, the plurality of connected chloride ion sensors 20 may share the wiring 23. Like the wiring 22, the wiring 23 is, for example, a wiring that connects the measurement unit 2 and the calculation unit 50, a wiring that connects the measurement unit 2 and a wireless transmission unit 3 described below, each chloride ion sensor 10 and an external power supply. Wiring for connecting to (not shown) and the like can be mentioned. The plurality of connected chloride ion sensors 20 may further share the calculation unit 50 and the wireless transmission unit 3.

FIG. 5 shows an example of the calculation unit 50. In the example of FIG. 5, the calculation unit 50 includes an input unit 51, an output unit 52, a storage unit 53, a calculation unit 54, and a control unit 55. As the calculation unit 50, for example, a known personal computer, PDA, tablet terminal or the like can be used.

The input unit 51 is an input unit for receiving input of various information necessary for executing the measurement method according to the present embodiment, and may have at least a terminal connected to the measurement unit 2. If necessary, a keyboard, a touch panel, a terminal connected to the moisture content meter 61 described later, and various switches may be provided.

The output unit 52 is an output unit that outputs various kinds of information necessary for executing the measurement method according to the present embodiment, and is configured as, for example, a monitor.

The storage unit 53 is a storage unit that stores various kinds of information necessary for the processing of the calculation unit 50, and is configured by, for example, a hard disk or another recording medium. In this embodiment, the characteristic information DB 40 is provided. The characteristic information DB 40 is characteristic information that specifies the interrelationship between the impedance of the concrete structure 100, the frequency corresponding to the impedance, the moisture content, and the chloride ion concentration, or the phase angle of the impedance peaks. It includes characteristic information that specifies the correlation between the peak frequency, the water content, and the chloride ion concentration. The characteristic information can be acquired, for example, by measuring the impedance and frequency of the concrete structure 100 whose moisture content and salt concentration are known in advance, or the peak frequency at which the phase angle of the impedance peaks. Alternatively, it may be obtained from publicly known documents such as Japanese Patent Laid-Open No. 2012-184948 and Japanese Patent No. 6338238.
The characteristic information DB 40 does not have to store all the raw data, but may store only some of the raw data and generate other data by interpolation as necessary. For example, when storing data indicating the relationship between frequency and impedance, only impedances corresponding to a plurality of intermittent frequencies are stored as raw data, and impedances corresponding to frequencies between these plurality of frequencies are stored. , May be generated by interpolation based on raw data.

The calculation unit 54 calculates the characteristic information stored in the characteristic information DB 40 based on the impedance measured using the measuring unit 2 and the frequency corresponding to the impedance, or the peak frequency at which the phase angle of the impedance reaches a peak. By reference, the water content and the chloride ion concentration of the concrete structure 100 are calculated. Specifically, the calculation unit 54 includes a CPU, various programs that are interpreted and executed on the CPU (including a basic control program such as an OS and an application program that is started on the OS and realizes a specific function), and It is configured to include an internal memory such as a RAM for storing programs and various data. In particular, the chloride ion concentration calculating program according to the present embodiment is stored in a readable recording medium and installed in the arithmetic unit 5 from the recording medium, thereby substantially configuring the calculating unit 54.

Further, the control unit 55 controls each unit constituting the calculation unit 50, and controls the measurement unit 2 to start and end the measurement. Like the calculation unit 54, the control unit 55 includes a CPU, an internal memory such as a RAM for storing various programs interpreted and executed on the CPU, and programs and various data.

(Second embodiment)
FIG. 3 is a schematic diagram showing a second embodiment of the chloride ion sensor of the present embodiment. The chloride ion sensor 10 shown in the example of FIG. 3 is different from that of the first embodiment in that the wireless transmission unit 3 is provided and the wireless transmission unit 3 and the measurement unit 2 are connected.
The wireless transmission unit 3 wirelessly transmits information such as impedance measured by the measurement unit 2 to the calculation unit 50. The signal to be transmitted is not particularly limited, and may be an analog system, a digital system, or any system. Further, the transmission form may be any communication form such as light, radio wave, electromagnetic wave.
When there are a plurality of chloride ion sensors 10 as in the example of FIG. 2, each wireless transmission unit 3 outputs the identification information of the chloride ion sensor 10 so that it can be identified from which chloride ion sensor 10. It is sent to the calculation unit 50 together with the impedance information.

The wireless transmission unit 3 may include a battery (not shown) that supplies electric power. The battery supplies at least the necessary power to the wireless transmission unit 3. Moreover, you may supply electric power from the battery to the measurement part 2 as needed. By supplying necessary power to the wireless transmission unit 3 and the measurement unit 2 by the battery, the chloride ion sensor 10 does not require external wiring (for example, the wiring 22 and the wiring 23 in FIG. 2), and has a simple configuration. Become. As a result, the concrete structure 100 can be installed anywhere.

(Third Embodiment)
FIG. 4 is a schematic diagram showing a third embodiment of the chloride ion sensor of the present embodiment. In the third embodiment, a moisture content meter 61 is provided separately from the chloride ion sensor 10 of the first embodiment, and the moisture content meter 61 is connected to the calculation unit 50. The water content meter 61 acquires the water content of the concrete structure 100. In the first embodiment, the water content and the chloride ion concentration are calculated from the measured values such as impedance. On the other hand, in the present embodiment, the calculation accuracy of the chloride ion concentration is improved by using the water content as the measured value.

The water content meter 61 is a water content information acquisition unit that acquires the water content of the concrete structure 100. This moisture content meter 61 can be appropriately selected from known methods, for example, a method of optically detecting moisture by reflection of infrared rays, or a change in dielectric constant (high frequency capacity) due to moisture in concrete, and detecting the moisture content. Examples include a method of measuring water content based on the result.

(Fourth Embodiment)
FIG. 9 is a schematic view showing a fourth embodiment of the chloride ion sensor of the present embodiment. In the present embodiment, at least a part of the wiring (conducting wire 8) between the impedance detection unit 2 and the electrode 4 is configured by the pattern wiring 8 a formed on the base material 6 including the electrode 4. That is, in the present embodiment, the electrode sheet with patterned wiring 200 including the patterned wiring 8 a and the pair of electrodes 4 on the base material 6 is used. The pattern wiring 8a and the electrode 4 may be formed on the same surface, or the pattern wiring 8a may be formed on the surface opposite to the electrode 4 and connected through the opening of the base material.
The pattern wiring 8a is formed by, for example, printing an ink containing a conductive material between the electrode 4 on the base material 6 and a terminal connected to the impedance detection portion 2 arranged at an end of the base material 6 or the like. And patterning,
Like a flexible circuit, a conductive metal is laminated on the base material 6 by vapor deposition, metal foil lamination, plating, etc., a pattern is formed by etching, and then an electrode 4 to be used is formed, and wiring for the impedance detection unit 2 is formed. The method of connecting is mentioned.
If the contact resistance between the wiring pattern 8a and the electrode 4 is small, it can be connected by printing as it is. If the contact resistance is high, the wiring may be connected with a conductive adhesive such as a silver paste or a metal filler. A protective portion 7 for sealing the wiring pattern may be further provided on the wiring pattern 8a, or may be wholly or partially laminated with a laminating film in which a base material having weather resistance and an adhesive are laminated. Good.
When the pattern wiring 8a is printed on the same surface as the electrode 4, the electrode can be formed at the end of the wiring, and the electrode can be partially or entirely exposed and heated and melted to be placed on the surface of the concrete structure 100. When the pattern wiring 8a is printed on the surface opposite to the electrode 4 of the electrode sheet with pattern wiring, a through hole is provided in the base material of the voltage detecting portion or the electrode portion, and conductive ink, a conductive adhesive, or a hot melt electrode is provided therein. It is also possible to join by embedding. Also in that case, the protective portion 7 may be provided on the pattern wiring 8a, and the whole or a part may be laminated with a laminating film in which a weather resistant substrate and an adhesive are laminated.

In this implementation, the printed wiring can be easily formed and is also excellent in flexibility, which is preferable. The conductive ink used for printed wiring contains at least conductive fine particles, and may contain other components such as a binder component and a solvent, if necessary.

The conductive fine particles may be sintered into a sintered body in the formed conductive wiring, but it is preferable that a plurality of conductive fine particles contact each other to exhibit conductivity.

Examples of the conductive fine particles include metal fine particles, carbon fine particles, and conductive oxide fine particles.
Examples of the metal fine particles include powders of metal such as gold, silver, copper, nickel, chromium, palladium, rhodium, ruthenium, indium, aluminum, tungsten, molbutene, platinum, copper-nickel alloy, silver-palladium alloy, Examples thereof include alloy powders such as copper-tin alloys, silver-copper alloys, and copper-manganese alloys, and metal-coated powders obtained by coating the surface of the above-mentioned single metal powder or alloy powder with silver or the like. Further, examples of the carbon fine particles include carbon black, graphite, carbon nanotubes and the like. Examples of the conductive oxide fine particles include silver oxide, indium oxide, tin oxide, zinc oxide, ruthenium oxide and the like. The conductive fine particles may be used alone or in combination of two or more.
In the present embodiment, from the viewpoint of long-term reliability of the conductive wiring, it is preferable to use fine carbon particles having excellent weather resistance such as water resistance and acid resistance.

The shape of the conductive fine particles is not particularly limited, and an amorphous shape, an aggregate shape, a scale shape, a microcrystalline shape, a spherical shape, a flake shape, a wire shape, or the like can be appropriately used. The average particle size of the conductive fine particles is not particularly limited, but is preferably 0.1 μm or more and 50 μm or less, and 0.5 μm or more and 30 μm or less from the viewpoint of dispersibility in the conductive ink and conductivity after wiring. Is more preferable.

The conductive ink preferably contains a binder component. As the binder component, it is preferable to include a resin from the viewpoint of film-forming property, adhesion after film-forming, flexibility and the like. The resin can be appropriately selected and used from resins used for conductive wiring. Examples of the resin include acrylic resin, vinyl ether resin, polyether resin, polyester resin, polyurethane resin, epoxy resin, phenoxy resin, polycarbonate resin, polyvinyl chloride resin, polyolefin resin, styrene block. A copolymer resin, a polyamide resin, a polyimide resin, etc. are mentioned, and they can be used individually by 1 type or in combination of 2 or more types.

The content ratio of the conductive fine particles in the pattern wiring 8a is preferably 50% by mass or more and 95% by mass or less, and more preferably 60% by mass or more and 90% by mass or less with respect to the total amount of the pattern wiring 8a. Further, the content ratio of the binder component in the pattern wiring 8a is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less with respect to the total amount of the pattern wiring 8a.
When the content ratio of the conductive fine particles is at least the above lower limit value, the conductive wiring has excellent conductivity. Further, when the content ratio of the binder component is at least the above lower limit, the film forming property and the adhesion to the base material 6 are improved, and flexibility can be imparted to the conductive wiring of the electrode sheet with conductive wiring. it can.

The pattern wiring 8a of the electrode sheet 200 with pattern wiring is prepared by, for example, preparing a conductive ink containing the conductive fine particles, the binder component, and optionally a solvent, and then applying the conductive ink on a substrate. It can be formed by printing on, and removing the solvent if necessary.
The solvent may be appropriately selected according to the printing method. The printing method may be appropriately selected from known printing techniques such as a gravure printing method, a screen printing method, a flexo printing method, an inkjet method, and the like, depending on the composition of the conductive ink and the film thickness of the pattern wiring.

The thickness of the pattern wiring 8a of the electrode sheet 200 with pattern wiring is not particularly limited, and from the viewpoint of achieving both conductivity and flexibility, for example, it can be 1 μm or more and 500 μm or less, and 10 μm or more and 300 μm or less are preferable. In addition, the width of the conductive wiring of the print-type sensor sheet is not limited, and may be a width that provides the necessary conductivity. For example, it can be 0.1 mm or more, and preferably 1 mm to 100 mm. Note that the plurality of conductive wirings may have the same thickness or width, or may have different thicknesses or widths.

<Protective part (protective layer) of electrode sheet with pattern wiring>
The protective portion 7 of the electrode sheet with pattern wiring is a layer provided at least on the pattern wiring 8a, and suppresses damage to the pattern wiring 8a and contact with water, oxygen, acid, alkali, etc., and long-term reliability. To improve. The protective part 7 can be formed as a protective layer by, for example, laminating a sheet similar to the sheet base material of the electrode sheet with conductive wiring.

[Chloride ion concentration measurement method]
The chloride ion concentration measuring method of this embodiment is
A measurement method for measuring chloride ion concentration in a concrete structure,
A preparatory step of preparing the chloride ion sensor,
A pair of electrodes provided in the chloride ion sensor, a bonding step for respectively bonding to the surface of the concrete structure,
And a measuring step for measuring impedance in a state where an alternating current is passed through the concrete body between the pair of electrodes,
The adhering step includes a step of adhering to the concrete structure by heating and melting the hot melt electrode.

Hereinafter, an embodiment of the corrosion detection method of the present invention will be described with reference to FIG. FIG. 6 is a flowchart showing an example of a chloride ion concentration measuring method.
First, the chloride ion sensor 10 is prepared (S1: preparation step). Next, the pair of electrodes 1a and 1b and the surface of the concrete structure 100 are electrically contacted via the hot melt electrode (S3: bonding step). Then, the impedance is measured in a state where an alternating current is passed between the pair of electrodes through a concrete body (S4: measuring step). The obtained measurement result is sent to the calculation unit by wire or wirelessly when the chloride ion sensor 10 includes the wireless transmission unit 3 (S5: wireless transmission process), and the characteristic information DB 40 is stored in the calculation unit 50. The chloride ion concentration is calculated with reference (S6: calculation step).

In the present embodiment, the bonding step includes a step of heating and melting the hot melt electrodes included in the electrodes 1a and 1b. By such a method, even if there are irregularities on the surface of the concrete structure 100, the hot melt electrode is deformed along the irregularities during melting and firmly adhered. As a result, electrical contact with the surface of the concrete structure 100 can be favorably maintained for a long period of time.

Further, since the chloride ion sensor using the electrode sheet with patterned wiring 200 is an electrode sheet in which the conducting wire 8 is formed on the base material in advance, a corrosion sensor is installed when performing large-area / multipoint spontaneous potential measurement. Becomes even easier.

Hereinafter, the present invention will be described specifically and in detail with reference to Examples, but these Examples are merely one aspect of the present invention, and the present invention is not limited to these Examples.

[Manufacture of electrodes for chloride ion sensors]
<Production Example 1>
A hot melt resin based on SIS (styrene-isoprene-styrene) elastomer and a carbon filler were added to a tabletop kneader equipped with a heating device, and heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a polyimide film (Kapton 200EN: manufactured by Toray DuPont Co., Ltd.) to a thickness of 200 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 2 × 10 ¹ Ωcm.

<Production Example 2>
A hot melt resin based on SIS (styrene-isoprene-styrene) elastomer and a carbon filler were added to a tabletop kneader equipped with a heating device, and heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN (polyethylene naphthalate) film to a thickness of 100 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 3 × 10 ³ Ωcm.

<Production Example 3>
A hot melt resin based on SEPS (styrene / ethylene / propylene / styrene) elastomer and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film with a thickness of 200 μm to obtain an electrode having a base material. The volume resistivity of the electrode part was 2 × 10 ⁻¹ Ωcm.

<Production Example 4>
A hot melt resin based on SEPS (styrene / ethylene / propylene / styrene) elastomer and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a polyimide film with a thickness of 1000 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 2 × 10 ¹ Ωcm.

<Production Example 5>
A hot melt resin based on SEBS (styrene / ethylene / butylene / styrene) elastomer and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film with a thickness of 300 μm to obtain an electrode having a base material. The volume resistivity of the electrode part was 6 × 10 ¹ Ωcm.

<Production Example 6>
A hot melt resin based on a polyamide-based thermoplastic resin and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C. for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film to a thickness of 150 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 5 × 10 ¹ Ωcm.

<Production Example 7>
A hot melt resin based on a polyester thermoplastic resin and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C. for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film to a thickness of 500 μm to obtain an electrode having a base material. The volume resistivity of the electrode part was 4 × 10 ³ Ωcm.

<Production Example 8>
A hot melt resin based on a polyolefin-based thermoplastic resin and a carbon filler were added to a table-top kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C. for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film with a thickness of 250 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 1 × 10 ¹ Ωcm.

<Production Example 9>
A hot melt resin based on a polyurethane-based thermoplastic resin and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C. for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film to a thickness of 400 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 1 × 10 ¹ Ωcm.

<Production Example 10>
A hot melt resin based on a polyvinyl chloride (PVC) thermoplastic resin and a carbon filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C. for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot melt electrode was laminated on a PEN film with a thickness of 200 μm to obtain an electrode having a base material. The volume resistivity of the electrode portion was 1 × 10 ¹ Ωcm.

<Production Example 11>
A hot melt resin based on SEPS (styrene / ethylene / propylene / styrene) elastomer and a silver filler were added to a tabletop kneader equipped with a heating device, and the mixture was heated and stirred at 130 to 180 ° C for 3 hours. It was confirmed that the elastomer did not remain unmelted, and a hot melt electrode was obtained. The prepared hot-melt electrode was laminated on a PEN substrate to a thickness of 200 μm to obtain an electrode. The volume resistivity of the electrode portion was 4 × 10 ⁻⁴ Ωcm.

<Production Example of Hot Melt Resin Composition and Sealant Sheet>
A hot melt resin based on SIS (styrene / isoprene / styrene) elastomer is sandwiched between release films, and hot pressed at 100 ° C and 100 kgf / cm ² for 30 seconds with a tester tabletop test press machine to obtain a film thickness of 200 It was processed into a sheet having a size of up to 300 μm to obtain a sealing material sheet 1.

<Production Example 12: Electrode sheet with pattern wiring>
As shown in FIG. 9, a conductive carbon ink (carbon-based conductive paste RA FS 090: manufactured by Toyo Ink Co., Ltd.) on a 300 mm × 100 mm polyamide film (Kapton 200EN: manufactured by Toray DuPont Co., Ltd.) was used to form two 10 mm wide lines between the lines. Printed in a space of 5 mm and heat-dried at 100 ° C. for 30 minutes, and further, the hot melt electrode prepared in Example 1 is 200 μm thick on a polyimide film (Kapton: manufactured by Toray DuPont Co., Ltd.) so as to have a size of 40 mm × 40 mm. And the encapsulant sheet on the base material so as to cover the wiring part while avoiding the electrode part, and hot roll laminating is performed at 150 ° C., 4 kgf / cm ² , and 1 m / min from the release film to form an electrode. An electrode sheet 200 with a pattern wiring including carbon wiring and a sealing material was obtained (FIG. 9). The volume resistivity of the electrode portion 4 was 2 × 10 ¹ Ωcm.

<Production Example 13: Electrode sheet with pattern wiring>
As shown in FIG. 9, a conductive silver paste (RA FS 007: manufactured by Toyo Ink Co., Ltd.) is printed on a 300 mm × 100 mm polyamide film (Kapton 200 EN: manufactured by Toray DuPont Co., Ltd.) in a width of 5 mm to form two 10 mm wide lines. Then, it is dried by heating at 100 ° C. for 30 minutes, and the hot melt electrode prepared in Example 1 is further laminated on a polyimide film (Kapton: manufactured by Toray DuPont Co., Ltd.) so as to have a size of 40 mm × 40 mm, and a thickness of 200 μm. Further, avoiding the electrode part, a sealing material sheet is covered on the base material so as to cover the wiring part, and hot roll laminating is performed from above the release film at 150 ° C., 4 kgf / cm ² , 1 m / min to seal the electrode, carbon wiring and An electrode sheet with a pattern wiring 200 having a stopper was obtained (FIG. 9). The volume resistivity of the electrode portion 4 was 2 × 10 ¹ Ωcm.
<Production Example 14: Electrode sheet with pattern wiring>
As shown in FIG. 9, two lines with a width of 1 mm and a conductive line 8 with a space between lines of 5 mm are copper-etched on a substrate of a 300 mm × 100 mm single-sided polyimide copper clad laminate (F30-VC1: manufactured by Nikkan Kogyo Co., Ltd.). Then, a polyimide coverlay film (Nicaflex CSKE base film thickness 25 μm: made by Nikkan Kogyo Co., Ltd.) is attached on the base material so as to avoid the electrode portion and cover the wiring portion, and the coverlay portion is 160 ° C. The wiring portion was sealed by hot pressing for 90 minutes at a molding pressure of 4 MPa. Further, the hot-melt electrode prepared in the example was laminated on the base material so as to have a size of 40 mm × 40 mm with a thickness of 300 mm, and the electrode and the wiring pattern with the copper wiring by etching and the electrode with pattern wiring provided with the encapsulant by the coverlay. A sheet 200 was obtained (Fig. 9). The volume resistivity of the electrode portion 4 was 2 × 10 ¹ Ωcm.

<Comparative Production Example 1>
Ionic conductivity is obtained by laminating an ion conductive gel formed by mixing a high molecular polymer (Poly-styrene-b-ethylene oxide-b-styrene): PS-PEO-PS) and an ionic liquid on an aluminum foil. I got an electrode. The ionic conductivity of the electrode portion was 4 × 10 ⁻² Scm.

<Example 1>
(Measurement)
1. Measurement of Volume Resistivity The laminate of the electrode and the polyimide film produced in Production Example 1 was cut into 1.5 cm × 3 cm, and a low resistivity meter (Mitsubishi Chemical Analytech Co., Ltd .: Lorester GX MCP-T700) was used. The volume resistivity of the electrode portion was measured. It measured 3 times and made the average value the measured value.

2. Measurement of Adhesive Strength The adhesive strength was measured by using a tensile tester EX-SX manufactured by Shimadzu Corporation. A sheet of 25 mm width composed of a laminate of a hot melt electrode having a thickness of 200 μm and a polyimide film obtained in Production Example 1 was subjected to a surface polishing treatment with a grinder to obtain a 7 cm × 7 cm concrete adherend surface, which was hot. The melt electrode side was attached, and a plate heated to 200 ° C. was pressed against the base material for 1 minute to adhere to the concrete. After the heating was completed, the sample was allowed to stand for 24 hours until it returned to room temperature, which was used as a measurement sample. The measuring method was such that the edge of the sheet was at an angle of 90 degrees and a speed of 50 mm / min. The adhesive force was evaluated from the load when peeled off with. Grinder used: Monotaro Slim Disc Grinder (MRO-100DG)

3. Compound Corrosion Resistance Test As the compound corrosion test, a test based on the Japan Automobile Manufacturers Association Standard (JASO) M609 / M610 was carried out for a long time. Specifically, the sample was placed inside the complex corrosion tester (BQD-2) in a state of being inclined at 70 degrees with respect to the ground. The complex corrosion condition of the sample is as follows: 5% NaCl, salt spray at 35 ° C for 2 hours, then 4 hours in a dry environment of 50% RH and 60 ° C, and a wet environment of 95% RH and 50 ° C. I put it down for two hours. This cycle was performed 200 times. After the implementation, the measurement sample was collected, and the deterioration determination was performed by comparing the results before and after the following test.

A. Change in conductivity Samples for measurement of complex corrosion test are 1. It was prepared in the same manner as the measurement of the volume resistivity, and at the same time, the resistivity was also measured. The sample was put into a complex corrosion tester, a corrosion cycle test was performed under the above conditions, and then the volume resistivity of the sample was measured by the same method.
◎ when the volume resistivity is less than 1 × 10 ³ Ωcm before and after the complex corrosion test, ◯ when the volume resistivity is less than 1 × 10 ⁵ Ωcm before and after the complex corrosion test, and other In the case of, it was marked with x.

B. Change in Adhesiveness The measurement sample prepared in Example 1 in which the hot melt electrode adhered to concrete was subjected to a corrosion cycle test under the above conditions, and then the adhesive strength was evaluated by the same method. When the adhesive strength before the test is 10 N or more and the decrease in the adhesive strength value after the corrosion test is less than 10 N, the adhesive strength before the test is 5 N or more and the adhesive strength value after the corrosion test decreases by less than 5 N. In other cases, it was ◯, and in other cases, it was x.
Grinder used: Monotaro Slim Disc Grinder (MRO-100DG)

4. Chloride ion measurement (creation of characteristic information database)
The concrete specimen used for impedance measurement was prepared as follows as a rectangular parallelepiped having a size of 200 × 100 × 100 cm.
Four kinds of specimens containing 0.5 kg, 1 kg, 5 kg, and 10 kg per 1 m ^{3 of} chloride were manufactured by pouring using water, cement, and sand. Further, by adjusting the water content of each concrete specimen to 0.5%, 1%, 5%, 10%, a total of 16 types of concrete specimens with known chloride content and moisture content were prepared. A laminate composed of two pairs of hot melt electrode sheets and a polyimide film, each having a thickness of 200 μm, a size of 4 × 4 cm, and an interval of 10 cm, was attached on each surface of each of the concrete specimens, and heated at 200 ° C. Two pairs of electrodes were bonded to the surface of each concrete specimen by pressure bonding.
AC impedance can be measured by connecting two pairs of electrodes bonded to the same concrete specimen surface to the LCR meter via electric wires.
The frequency characteristics of the real part and the imaginary part of the AC impedance between the electrodes of each concrete specimen were measured. The frequency was swept from 0.1 Hz to 10 MHz.
The value of the AC impedance at each water content / salt concentration was plotted for each frequency to create a characteristic information database.

Next, a concrete specimen having a known water content and a chloride ion content shown in Table 2 was prepared, and the electrode after the complex corrosion resistance test of Example 1 was treated on the surface of the concrete specimen in the same manner as in the creation of the above database. Glued on.
Measurement was made possible by connecting two pairs of electrodes that were bonded to the surface of the same concrete specimen to the LCR meter. The water content of the concrete specimen was measured in advance using a moisture meter (HI-520-2 manufactured by KETT). For the quantitative evaluation of chloride ion concentration, the frequency characteristics of the real part and the imaginary part of the AC impedance between the two pairs of electrodes are measured, and the measured water content and AC impedance value are applied to the characteristic information database by the calibration curve method. The chloride ion content was calculated. The frequency was swept from 0.1 Hz to 10 MHz. The impedance of the prepared specimen was measured, and when the chloride concentration could be quantified, it was marked with ◯, and the others were marked with x.

<Comparative Example 1>
The following measurements were performed using the ion gel electrode prepared in Comparative Production Example 1 laminated on an aluminum substrate with a thickness of 500 μm. The conductivity was evaluated using the AC impedance method.

<Measurement>
1. Measurement of ionic conductivity The ionic conductivity of the ion gel electrode prepared in Comparative Production Example 1 was measured using an impedance analyzer. It measured 3 times and made the average value the measured value.

2. Measurement of Adhesive Strength The adhesive strength was measured by using a tensile tester EX-SX manufactured by Shimadzu Corporation. To a concrete adherend surface of 7 cm × 7 cm, which was obtained in Comparative Production Example 1, a sheet of 25 mm width composed of a laminate of an ion gel electrode having a thickness of 500 μm and an aluminum base material was surface-polished with a grinder. Adhesion was performed by sticking the ion gel electrode side. The measuring method of the adhesive force is as follows: the edge of the sheet is at an angle of 90 degrees and the speed is 50 mm / min. The adhesive force was evaluated from the load when peeled off with.
Grinder used: Monotaro Slim Disc Grinder (MRO-100DG)

3. Compound Corrosion Resistance Test As the compound corrosion test, a test based on the Japan Automobile Manufacturers Association Standard (JASO) M609 / M610 was carried out for a long time. Specifically, the sample was placed inside the complex corrosion tester (BQD-2) in a state of being inclined at 70 degrees with respect to the ground. The complex corrosion condition of the sample is as follows: 5% NaCl, salt spray at 35 ° C for 2 hours, then 4 hours in a dry environment of 50% RH and 60 ° C, and a wet environment of 95% RH and 50 ° C. I put it down for two hours. This cycle was performed 200 times. After the implementation, the measurement sample was collected, and the deterioration determination was performed by comparing the results before and after the following test.

A. Change in conductivity Samples for measurement of complex corrosion test are 1. It was prepared in the same manner as the measurement of ionic conductivity, and at the same time, the resistivity was also measured. The sample was put into a complex corrosion tester, a corrosion cycle test was performed under the above conditions, and then the conductivity of the sample was measured by the same method. When the ionic conductivity is 1 × 10 ⁻³ S / cm or more before and after the complex corrosion test, ◎, and the ionic conductivity is 1 × 10 ⁻⁵ S / cm or more before and after the complex corrosion test. In other cases, it was ◯, and in other cases, it was x.

B. Change in Adhesiveness The measurement sample prepared in Comparative Example 1 in which the ion gel electrode adhered to concrete was subjected to a corrosion cycle test under the above conditions, and then the adhesive strength was evaluated by the same method. When the adhesive strength before the test is 10 N or more and the decrease in the adhesive strength value after the corrosion test is less than 10 N, the adhesive strength before the test is 5 N or more and the adhesive strength value after the corrosion test decreases by less than 5 N. In other cases, it was ◯, and in other cases, it was x.
Grinder used: Monotaro Slim Disc Grinder (MRO-100DG)

4. Chloride ion measurement (creation of characteristic information database)
The concrete specimen used for impedance measurement was prepared as follows as a rectangular parallelepiped having a size of 200 × 100 × 100 cm.
Four kinds of specimens containing 0.5 kg, 1 kg, 5 kg, and 10 kg per 1 m ^{3 of} chloride were manufactured by pouring using water, cement, and sand. Furthermore, by adjusting the water content of each concrete specimen to 0.5%, 1%, 5%, 10%, a total of 16 types of concrete specimens with known chloride content and moisture content were prepared. In Comparative Example 1 The surface of each concrete specimen by sticking a laminate composed of two pairs of ion gel electrode sheets and a polyimide film, which are separated by a thickness of 200 μm, a size of 4 × 4 cm, and an interval of 10 cm, on each surface of each concrete specimen. Two pairs of electrodes were adhered to.
AC impedance can be measured by connecting two pairs of electrodes bonded to the same concrete specimen surface to the LCR meter via electric wires.
The frequency characteristics of the real part and the imaginary part of the AC impedance between the electrodes of each concrete specimen were measured. The frequency was swept from 0.1 Hz to 10 MHz.
The value of the AC impedance at each water content / salt concentration was plotted for each frequency to create a characteristic information database.

Next, a concrete specimen having a known water content and a chloride ion content shown in Table 2 was prepared, and the electrode after the complex corrosion resistance test of Comparative Example 1 was prepared on the surface of the concrete specimen in the same manner as in the creation of the above database. Glued on.
Measurement was made possible by connecting two pairs of electrodes that were bonded to the surface of the same concrete specimen to the LCR meter. The water content of the concrete specimen was measured in advance using a moisture meter (HI-520-2 manufactured by KETT). For the quantitative evaluation of chloride ion concentration, the frequency characteristics of the real part and the imaginary part of the AC impedance between the two pairs of electrodes are measured, and the measured water content and AC impedance value are applied to the characteristic information database by the calibration curve method. The chloride ion content was calculated. The frequency was swept from 0.1 Hz to 10 MHz. The impedance of the prepared specimen was measured, and when the chloride concentration could be quantified, it was marked with ◯, and the others were marked with x.

<Examples 2 to 14>
In the same manner as in Example 1, Examples 2 to 14 were prepared and measured. The results are shown in Table 2.

This application claims priority based on Japanese Patent Application No. 2018-194321 filed on October 15, 2018, and incorporates all of the disclosure thereof.

1a, 1b Electrode 2 Measuring part 3 Wireless transmitting part 4 Hot melt electrode 5 Conductive layer 6 Base material 7 Protecting part 8 Conductive wire 10 Chloride ion sensor 20 Connected chloride ion sensor 21, 22, 23 Wiring 31 Sheet-like base material 40 Characteristic Information Database 50 Calculation Section 51 Input Section 52 Output Section 53 Storage Section 54 Calculation Section 55 Control Section 61 Moisture Content Meter 100 Concrete Structure 101 Inner Wall 200 Electrode Sheet with Pattern Wiring

Claims (13)

1. A sensor for measuring chloride ion concentration in a concrete structure,
   At least a pair of electrodes spaced apart from each other on the surface of the concrete structure;
   A measuring unit for measuring impedance in a state in which an alternating current is applied between the at least one pair of electrodes,
   The chloride ion sensor, wherein the at least one pair of electrodes has a hot melt electrode containing a hot melt resin in which a conductive filler is dispersed.
2. The chloride ion sensor according to claim 1, wherein the conductive filler is silver or conductive carbon.
3. The chloride ion sensor according to claim 1 or 2, wherein the hot melt resin contains a thermoplastic elastomer.
4. The chloride ion sensor according to any one of claims 1 to 3, wherein the electrode has a conductive layer on the hot melt electrode.
5. The chloride ion sensor according to any one of claims 1 to 4, further comprising a base material on the electrode.
6. The chloride ion sensor according to any one of claims 1 to 5, wherein the electrode is formed into a sheet.
7. The chloride ion sensor according to any one of claims 1 to 6, which has a plurality of the electrodes, and the plurality of electrodes are arranged in a pattern on a sheet-shaped base material.
8. 8. The electrode according to claim 5, wherein the electrode and the measurement unit are connected by a conductive wiring, and at least a part of the conductive wiring is a pattern wiring formed on at least one surface of the base material. The chloride ion sensor according to one item.
9. The chloride ion sensor according to any one of claims 1 to 8, further comprising a wireless transmission unit that wirelessly transmits information based on the measured impedance.
10. The chloride ion sensor according to claim 9, wherein the wireless transmission unit further includes a battery that supplies electric power.
11. A measurement method for measuring chloride ion concentration in a concrete structure,
    A preparatory step of preparing the chloride ion sensor according to any one of claims 1 to 10;
    At least a pair of electrodes provided in the chloride ion sensor, a bonding step for respectively bonding to the surface of the concrete structure,
    A measuring step of measuring the impedance in the state of flowing an alternating current through the concrete body between the at least a pair of electrodes,
    The chloride ion concentration measuring method, wherein the adhering step includes a step of adhering to the concrete structure by heating and melting the hot melt electrode.
12. Furthermore, it has a calculation step of calculating the chloride ion concentration from the measured impedance,
    The chloride ion concentration measuring method according to claim 11, wherein the calculating step calculates the chloride ion concentration based on at least the measured impedance obtained in the impedance measuring step.
13. The preparation step is a preparation step of preparing the chloride ion sensor according to claim 9 or 10,
    The chloride ion concentration measuring method according to claim 11 or 12, further comprising a step of wirelessly transmitting information based on the measured impedance obtained by the impedance measuring step.

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