JPH09100356A - Molded item contaning conductive powder and detecting method for load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded item which has a function to detect a low load applied to itself or to a structure using it. SOLUTION: A conductive phase 20 contg. a conductive powder 30 dispersed in such a manner as to make the state of electrical continuity capable of being measured is formed integrally with a molded item 10. When a load is applied to the item 10, the state of contact between particles of the powder 30 changes, changing the state of electrical continuity and thus enabling the detection of the change in load as the change in the state of electrical continuity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded product and a load detecting method having a breakage detecting function and a load history detecting function.

Various molded products such as plastic materials are molded from various molding materials into various shapes and sizes and used as various members and structures. In recent years, the material of such a molded body has been widely used as a structure having high strength by incorporating a reinforcing material such as a fiber into a composite material. However, a molded body made of various molding materials is affected by many factors when it is broken. Therefore, in order to expand the use as a structural material that particularly requires strength against breakage, it is necessary to secure the reliability of the strength and the like of the structure using the molded body. Therefore, in recent years, by imparting a sensor function to the molded body itself, it has been performed to detect some signal prior to the destruction of the molded body or a structure including the molded body. For example, in a concrete structure, there is a technique in which a glass fiber carbon fiber reinforced plastic molded body is used as a substitute for a reinforcing bar and an electric resistance of carbon fiber in the molded body is used as a sensor. This technique utilizes the fact that when a load is applied to a concrete structure and the embedded plastic molded body is deformed, the carbon fibers in the molded body are broken, and the resistance value changes.

According to this technique, the resistance value does not change so much in a concrete structure under a low load, and the carbon fiber is not cut until a crack that can be easily observed with the naked eye is generated when a force is applied. At the beginning, the resistance value suddenly increased. That is, by measuring the resistance value,
Although it can detect the precursor of the destruction of the concrete structure,
It could be detected when a crack occurred.

[0004]

However, it is not sufficient as a sensor for improving the reliability of a structure that it can be detected as a change in resistance value only at the same time as cracks that can be visually observed are generated. That is, it is necessary for the sensor to be able to detect the load and strain in the structure earlier than the occurrence of cracks, that is, under a low load. Therefore, it is an object of the present invention to provide the molded product itself with a function of detecting a low load applied to the molded product or a structure using the molded product.

[0005]

In order to solve the above-mentioned problems, the inventors of the present invention form a conductive phase containing a conductive powder integrally with a molded body made of various molding materials.
The present invention has been completed by discovering that the energized state of the conductive phase changes depending on the load applied to the molded body. That is, the invention according to claim 1 is a conductive powder-containing molded product, characterized in that the conductive powder-containing conductive phase capable of measuring an energized state is provided integrally with the molded product. is there. The invention described in claim 2 is the conductive powder-containing molded product according to claim 1, wherein the conductive powder is carbon powder and / or ceramic powder.
The invention described in claim 3 is the conductive powder-containing molded product according to claim 1 or 2, wherein the molded product is a plastic material. The invention according to claim 4 is the conductive powder-containing molded body according to claims 1 to 3, characterized in that a fiber bundle is arranged along the conductive phase. Further, the invention according to claim 5 is a concrete material comprising the conductive powder-containing molded body according to claims 1 to 4. Further, the invention according to claim 6 is characterized in that a conductive phase containing a conductive powder capable of measuring an energized state is integrally provided along a glass fiber bundle, and the glass fiber plastic material for concrete reinforcement. Is. Further, the invention according to claim 7 is the conductive phase of a molded body containing the conductive powder according to claims 1 to 4 or a structure including the conductive powder molded body according to claims 1 to 4. Is a method for detecting a load on a molded body or a structure. The invention described in claim 8 is a method for detecting a load on a concrete material, which comprises measuring the energization state of the conductive phase of the concrete material according to claim 5. Further, the invention according to claim 9 is characterized in that the conductive state of the conductive phase of a concrete material containing the glass fiber plastic material for concrete reinforcement according to claim 6 is measured. This is a method for detecting the load on a concrete material.

According to the present invention, the molded product itself is provided with a function of emitting a signal capable of detecting the breakage in advance, thereby improving the reliability of the molded product and the structure including the molded product against the damage. Is.

The molded product of the present invention is provided with a conductive powder, and has a conductive phase formed by this conductive powder. The conductive phase is provided integrally with the molded body. That is, the conductive phase is, on the inside or surface of the molded body,
It is in a tightly bound state.

The conductive phase can be from a conductive powder, or
It is configured to include a conductive powder so that the energized state can be measured. That is, in the conductive phase, the conductive paths are formed by contacting individual particles of the conductive powder. In addition,
In order to be able to measure the current-carrying state of the conductive phase, the molded body matrix must be an insulator, have a lower conductivity than the conductive phase, or the conductive phase must be electrically isolated from the molded body by some means. It must be in an insulated state. In the present invention, since the conductive phase, and further the conductive path is provided integrally with the molded body, a load is applied to the molded body, stress is generated, and strain occurs in the molded body, the effect In response to this, the distance between particles that are in contact with each other is changed, or the contact of particles is broken. That is,
The load applied to the molded body changes the contact state of the conductive particles, so that the cross-sectional area of the conductive path changes partially or the length of the conductive path changes. Therefore, the conduction state of the conductive path changes depending on the contact state of the conductive particles. That is,
The load applied to the molded body changes the energized state in the conductive path.

When the conductive path is formed by the state in which the conductive particles are in contact with each other, the contact state of the individual particles is smaller than that in the case where the conductive path is formed by continuous yarn such as carbon fiber. Only when it is changed, the energized state changes. Therefore, even if a load that causes only a slight strain or stress to be applied to the compact, the strain can be detected as a change in the energized state through a change in the contact state of the particles. Further, the conductive path formed of the fibrous body is strongly affected by elasticity of the fibrous body, critical elongation, etc. in the relationship between the load applied to the molded body and the energized state. However, in a conductive path consisting of particles, it is almost unnecessary to consider the effects of elasticity and critical elongation, so that the load applied to the molded product is more directly affected by such factors without being affected by such factors. Appears as a change in. Therefore, even a load that causes only a slight strain can be detected as a change in the energized state.

Further, in the case where a conductive path is formed by a fibrous body (continuous yarn) of the same conductive material in terms of electrical properties,
In the case where the conductive path is formed by the state in which the particles come into contact with each other, originally, the latter has lower electric conductivity and higher electric resistance. That is, in the conductive path in which the particle states are in contact with each other, it is originally difficult to conduct electricity,
By changing the form of the conductive path in this state and changing the contact state of the particles, a large amount of change in electric resistance can be obtained. Therefore, it is easy to detect a change in electrical resistance.

As described above, by measuring the change in the energized state of the conductive path provided in the molded body, the load applied to the molded body can be detected. Therefore, in advance, by measuring the load applied to the molded body and, for example, the change in electrical resistance, and confirming the relationship between the two, a structure composed of the molded body,
Alternatively, by measuring the change in the electrical resistance of the conductive phase in the structure including the molded body, the load applied to the structure including the molded body can be detected. Further, by confirming the relationship between the load applied to the molded product, the energized state, and the strain, the strain generated in the molded product can be detected.

Further, once the contact state of the particles in the conductive path is changed by the load, it does not return to the original state even when the load is removed, and the energized state is the same as the initial state. Don't Therefore, the load received in the past is recorded as a change in the energized state. Therefore, the load history of the molded body or the structure including the molded body can be estimated.

[0013]

Embodiments of the present invention will be described below in detail. The form and use of the molded product of the present invention are not limited. Specific examples include concrete materials, plastic materials, glass materials, aggregates and laminates of wood, molded bodies of natural or synthetic fibers and chips, and molded bodies of powder. In addition, these molded bodies,
It is also a structure at the same time. In particular, the molded product of the present invention is useful as a molded product as a structure that needs to detect breakage in advance. For example, as the molded body, a laminated material of concrete material, plastic material, or wood can be cited. In particular, the plastic material has a wide range of applications as a structural material because it can be reinforced by compounding a fiber material such as glass fiber, and since it is easy to integrally add a conductive phase, the molded article of the present invention Suitable as

The molded product of the present invention can also be used as a skeleton material or a filler in a state of being integrally contained in another material or in a mixed state. Specific examples of such a molded body include a plastic material and the like. In particular, the molded body of the present invention is useful as a skeleton material for a structure that needs to be detected in advance for breakage. As such a molded body, for example, various composite plastic materials such as fiber reinforced plastic materials used as a reinforcing material of a structure made of a concrete material can be cited.

As described above, the plastic material as the molded body of the present invention is useful both as various structures themselves and as materials contained in the structures. In addition, the plastic material is a material that has a low specific gravity and excellent corrosion resistance, and also has excellent moldability and processability that can sufficiently cope with complicated shapes. It is also useful in the present invention in that it is easy to compound the reinforcing material.

The type of plastic in the plastic material as the molded article of the present invention is not particularly limited. It can be selected depending on the application of the molded product. For example, the plastic of the reinforcing material used by mixing with the concrete material is preferably a vinyl ester resin having excellent alkali resistance. In addition, when the plastic constituting the molded body is a conductive polymer, if the one having a conductivity relatively lower than that of the conductive phase is used, the conductivity of the conductive phase is reduced. Can be measured.

The conductive powder used in the present invention is an aggregate of particles having conductivity. Such particles can be dispersed inside or on the surface of the molded body, and the material thereof is not limited as long as it has conductivity. Specific examples thereof include ceramic powders such as carbon powders, oxides, nitrides, and carbides, metal powders, and the like, but the breaking elongation of constituent particles is preferably small. This is because if the breaking elongation of the particles is small, the contact between the particles is divided under a low load to change the electric resistance, and the load or strain generated in the molded body can be detected even under a low load. The form of the particles may be spherical, flake-shaped, whisker-shaped or the like. The size of the particles can be used without any particular limitation. Examples of such conductive powder include carbon powder and ceramic powder such as titanium carbide and titanium nitride.

Here, examples of the load applied to the molded body include bending load, tensile load, compression load and the like.

When the conductive powder is dispersed in the compact, the conductive particles are brought into contact with each other to form a conductive path. The density (content) of the conductive particles in the conductive phase does not matter as long as the conductive paths are formed. The conductive paths are preferably formed by the particles of the conductive powder contacting each other partially and continuously. The term “partially and continuously contacting” means that adjacent particles do not come into perfect contact with each other, but come into contact with other particles at a certain part of the particle, and such contacting state continues. This is because when the conductive powder particles are dispersed in such a state, the shape of the conductive path is easily affected by the load applied to the molded body, and the load is easily detected as a change in electric resistance. If the content of the conductive particles in the conductive phase is high, the distance between the particles is short, and because the adhesion of the particles is high, the morphological change of the conductive path due to a constant load is reduced and the electrical resistance is reduced. The degree of change of is likely to be small. On the other hand, when the content of the conductive particles is low, on the contrary, the morphological change of the conductive path due to the load is large, and the degree of change of the electric resistance is likely to be large.

In order to form the conductive phase integrally with the molded body by applying the conductive powder to the molded body, the conductive powder may be directly applied to the molded body or the conductive powder may be applied to some carrier. In some cases, it is held and indirectly applied to the molded body. To directly apply the conductive powder to the molded body, for example,
At the time of molding the molded body, the conductive powder can be mixed with the molding material to obtain the molded body. Specifically, when the molded body is a plastic material, the conductive powder is mixed with the plastic material, or the conductive powder is applied to the surface of the molding material before curing while the molding material is being filled in the mold. Then, it is cured as it is, or further, a molding material is further applied thereto and then cured. In addition, when conductive powder is applied to the surface, a film or the like can be applied to avoid detachment of the conductive powder. Similarly, when the molded body is a molded body such as a concrete material, a glass material, a fiber, or a chip, the conductive powder can be directly applied. Further, when the molded body is a laminated body, it can be provided by interposing a conductive powder between the laminated materials.

Further, in order to indirectly apply the conductive powder to the molded body, a carrier having a certain shape is used, the conductive powder is supported on the carrier, and the carrier is applied to the molded body. By. Such a carrier can be selected from various shapes such as a rod shape, a sheet shape and a fibrous shape depending on the type of the molded body. As the material of the carrier, one kind or a plurality of kinds can be selected from plastics, natural or synthetic fibers, etc. in consideration of the form of the carrier. Further, it is necessary that the carrier does not have conductivity or has conductivity lower than that of the conductive powder used. The conductive powder-supporting carrier is dispersed, mixed, intervened, or attached to the surface of the molded body so as to be integrally provided in a state suitable for the molded body.

When the carrier is made of a plastic material, the conductive powder-carrying carrier can be formed by mixing and adhering the conductive powder to the inside or the surface of the plastic material. Also, if the carrier is a plastic material,
From the viewpoint of workability, the conductive powder-supporting carrier has a large degree of freedom in the form, and since the plastic also has strength, it is easy and convenient to include the conductive phase in a fixed form in the molded body. Furthermore, since it is possible to measure the electric resistance of the conductive phase by applying a load in the state of the carrier, the relationship between the load and the electric resistance can be measured at the stage of the carrier.

When the carrier is composed of fibers such as glass fiber and cellulose fiber, the material of the fiber contains conductive powder, or the conductive powder is attached to the surface of the fiber, or the conductive powder is dispersed. Fibers or sheet-like conductive powder-supporting carriers can be formed by impregnating fibers with the liquid thus obtained (for example, an adhesive liquid such as a vinyl alcohol solution). When the carrier is made of glass fiber, carbon fiber, or ceramic fiber, the molded body can be simultaneously reinforced with fibers.

Further, as the carrier, two or more kinds of materials can be used at the same time. For example, plastics and fibers can be used. In this case, for example, by impregnating and curing a pre-cured plastic liquid or sol in which conductive powder is dispersed into a fiber bundle formed by bundling fibers (continuous yarn), the fibers and the plastic are used as a carrier material. A conductive powder carrying carrier can be formed. According to this carrier, it is possible to give the carrier a certain shape so that the molded body can contain the conductive phase in a certain shape, and at the same time, to reinforce the carrier itself by the fiber bundle. Further, in the case of this carrier, since the conductive powder is applied along the fiber bundle in the carrier, the conductive phase is also formed in the formed body along the direction of reinforcement by the fiber bundle. Further, a plastic material in which both relatively short fibers and conductive powder are dispersed can be used as the conductive powder carrying carrier.

In particular, according to the conductive powder-supporting carrier obtained by using glass fiber, ceramic fiber and fiber bundles thereof as the carrier material at the same time as the plastic, it is possible to mold the molded body at the same time as forming the conductive phase. You can easily improve the strength of your body. Further, when the conductive phase is provided along the direction of the fiber bundle in the carrier, the strain generated along the arrangement direction of the fiber bundle, that is, the direction of reinforcement by the fiber bundle, and load change are detected. be able to.

As a form of existence of the conductive phase imparted to the molded body in this manner, there are a case where the entire molded body is a conductive phase and a case where the conductive phase is partially distributed. When the conductive phase is partially formed, the conductive phase may be in the form of a layer, a tube, or the like, and when the conductive phase is provided by a carrier, it follows the form of the carrier. Will be things. The existence form of the conductive phase is a form that is easily affected by load and strain, and the existence position in the molded body of the conductive phase is preferably the existence position that is easily affected by load and strain. . It is necessary to appropriately select the existing form and the existing position depending on the use of the molded product and the position where the molded product is provided. For example, with respect to a tensile load or a compressive load, it is preferable that the conductive phase has a long form along the direction of the load and is present along the direction in which the load is applied. Further, with respect to bending load, it is preferable to have a long form so that the load can be easily detected, and to exist so as to be orthogonal to the direction in which the load is applied.

To measure the energized state of the conductive phase provided integrally with the molded body means to measure parameters such as electric resistance, voltage, current, and conductivity of the conductive phase, which are generally necessary for knowing the energized state. Say. Which of these parameters is to be measured can be appropriately selected according to the measuring device used. It is preferable that terminals and lead wires are previously provided integrally with the molded body on both ends of the conductive phase provided on the molded body.

[0028]

EFFECTS OF THE INVENTION According to the present invention, the energized state of the conductive phase integrally provided in the molded body changes according to an increase in the load applied to the molded body. As a result, it is possible to reliably detect a change in load on the molded body or a structure including the molded body as a change in the energized state.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to FIGS. In this example, carbon powder having a particle diameter of 30 nm was used as the conductive powder, the material of the molded body was vinyl ester resin, and the glass fiber bundle was reinforced. Further, the same glass fiber bundle (R2220 manufactured by Asahi Fiber Glass) used for reinforcement was used as a carrier for applying carbon powder to the molded body. Table 1 shows the composition of the glass fiber bundle used, Table 2 shows the characteristics of the glass fiber bundle, and Table 3 shows the characteristics of the vinyl ester resin.

[0030]

[Table 1]

[Table 2]

[0031]

[Table 3]

I. Preparation of Test Specimen of Example [Preparation of Carbon Powder-Supporting Glass Fiber Bundle] A suspension in which carbon powder was uniformly dispersed at a ratio of 10 g in 40 ml of a 20% polyvinyl alcohol (WF804 manufactured by Chukyo Yushi Co., Ltd.) aqueous solution was prepared. This suspension was impregnated into a glass fiber bundle adjusted to a length of 120 mm. The impregnated glass fiber bundle was maintained in a bundle form and hardened, and as a result, a carbon powder-supported glass fiber bundle to which carbon powder as conductive powder was applied was formed along the glass fiber bundle. On each end side of this carbon powder carrying glass fiber bundle, a silver paste is applied to the surface, and further,
The lead wire to be connected to each of these end portions was integrally crimped with an aluminum film. At this time, the glass fiber content in the carbon powder-supporting glass fiber bundle was about 60 vol.
%. [Preparation of resin-impregnated glass fiber bundle] A glass fiber bundle adjusted to a length of 120 mm, vinyl ester resin: curing agent = 1
The resin liquid mixed at a ratio of 00: 1 was impregnated. In addition,
At this time, the glass fiber content in the resin-impregnated glass fiber bundle was set to about 45 vol%.

[Preparation of Test Pieces] A plurality of (5) resin-impregnated glass fiber bundles thus prepared are arranged in a molding die of a predetermined size, and one bundle of carbon powder-supporting glass fiber bundles is arranged. The resin liquid was injected by arranging the resin impregnated glass fiber bundles such that the resin impregnated glass fiber bundles of a plurality of bundles (15 bundles) were arranged side by side and arranged so as to be at a position of about 2 mm from the molding surface. As a result of filling the inside of the molding die with the resin liquid, the glass fiber bundle was placed in a plurality of layers on the left, right, and top and bottom. After this, wait for the resin liquid to harden, remove from the mold, take out the molded body,
After processing, a test piece having a length of 120 mm, a width of 10 mm and a thickness of 5 mm was obtained. The test piece is the molded product of the present invention. In this test piece, carbon powder was about 0.5 vol.
%, The carbon powder-supporting glass fiber bundle is arranged at a position of about 2 mm from one molding surface, and lead wires are led out to both ends in the longitudinal direction. FIG. 1 is a schematic view showing a sectional structure of a part of the test piece prepared in this manner. In this schematic diagram, in a test piece 10, a carbon powder-supporting glass fiber bundle 20 and a resin-impregnated glass fiber bundle 2
2 are provided integrally. In the carbon powder-supporting glass fiber bundle 20, a layer 40 containing carbon powder particles 30 is integrally formed inside and around the glass fiber bundle. The appearance of this test piece is shown in FIG. As shown in FIG. 2, the lead wires 60 are extended from the two end edge portions of the test piece 10 to the terminals 50 inside the test piece 10.

II. Preparation of Test Pieces of Comparative Example Further, tests of Comparative Examples 1 and 2 were carried out by adding two kinds of carbon fiber bundles as conductive materials to a molded body using the same glass fiber bundle and vinyl ester resin as those in Examples. Pieces were prepared. That is, a resin-impregnated glass fiber bundle was prepared by the same method as in Example except that the carbon fiber bundle (length 120 mm) was used in place of the carbon powder-supporting glass fiber bundle in Example, and the same method as in Example. The test pieces of Comparative Examples 1 and 2 were prepared according to. As the carbon fiber bundle of Comparative Example 1, Toray Trading Card T-400HB (modulus of elasticity 250 GPa, elongation at break 1.8%) was used, and the introduction amount of the carbon fiber bundle in one test piece was 0.23 vol%. Moreover, the carbon fiber bundle of Comparative Example 2 was manufactured by Toho Rayon, Vesfite UM63-12k-.
Using H50 (elastic modulus 617 GPa, elongation at break 0.6%), the amount of carbon fiber bundles introduced into one test piece was 0.93 vol%.

Next, these test pieces were subjected to a three-point bending test, and at the same time, the electric resistance of the conductive phase was measured.
The three-point bending test and the measurement of electric resistance were performed according to the following methods. [Three-Point Bending Test] In the examples, the test piece was set in a three-point bending tester so that the carbon powder-supporting glass fiber bundle in the test piece was placed at a position 2 mm from the tensile surface,
Span 50mm, Crosshead speed 1mm / min
The load (kgf) and strain (deflection) (mm) from the initial state to the occurrence of cracks were measured. The bending tester used was a Shimadzu Autograph AG-10TB computer-controlled precision universal tester manufactured by Shimadzu Corporation. Further, in the comparative example, the carbon fiber-supported glass fiber bundle is 2 m from the pulling surface.
The test piece was set in a three-point bending tester so that the test piece was placed at the position m, and the other conditions were the same as those of the examples.

[Measurement of Electrical Resistance] Using a digital multimeter Model 7561 manufactured by Yokogawa Electric Co., Ltd., the measurement was 2
The terminal method was used.

The results of the examples are shown in FIG. 3, and the results of the comparative examples are shown in FIGS. 3 to 5, the horizontal axis is the deflection, the left vertical axis is the load, and the right vertical axis is the electrical resistance value (change amount).
The relationship between load-deflection-electrical resistance value (change amount) in Examples and Comparative Examples is shown. As shown in FIG. 3, according to the results of the example, the electric resistance value was remarkably increased with the change of the load. That is, this is because the contact of the carbon powder particles in the conductive path was gradually divided in proportion to the increase in the load applied to the test piece. Therefore, in the test piece of this example, the change amount of the electric resistance value with respect to the change amount of the load is large, it is easy to detect an increase in the load as a change in the electric resistance, and from the measurement result of the electric resistance value, It is easy to detect the load and strain applied to the test piece. Further, the increase of the electric resistance value is proportional to the load in the range from the low load level to the high load level, and the change in the load can be detected with high sensitivity even at the low load level.

On the other hand, in Comparative Example 1, FIG.
As shown in, the electric resistance value gradually changed with the increase of the load, but the change amount was significantly smaller than that in the example. Then, when the load further increased and cracks occurred, the electric resistance value rapidly increased. That is, when a crack was formed, the carbon fiber was fractured and the electric resistance value was rapidly increased. Therefore, even if the test piece of this comparative example is used as a sensor, the load applied to the test piece cannot be easily detected from the increase of the electric resistance value, and the change of the electric resistance value at a low load level is small. Therefore, it is difficult to detect a change in load at a low load level.

In Comparative Example 2, as shown in FIG. 5, the electric resistance value hardly changed at the initial load, and the deflection increased sharply when the deflection became about 2 mm. That is, in this comparative example, the carbon fiber bundle was fractured at this point (when the deflection became about 2 mm). As is clear from FIG. 5, in this comparative example,
Before and after the deflection reached 2 mm, it was impossible to detect an increase in load as an increase in electric resistance. That is, before the deflection reaches 2 mm, the change in the electric resistance value is too small to be detected, and
Immediately after exceeding mm, the electric resistance value increased to infinity, so that the subsequent load change could not be detected as a change in the electric resistance value. Therefore, when a carbon fiber bundle having a small elongation at break is used, the fiber bundle is divided under a low load, but the electrical resistance value changes only when the fiber bundle is broken, which is common to Comparative Example 1. . Therefore, as in Comparative Example 1, it is difficult to measure the electric resistance value using the test piece as a sensor to detect the change in the load applied to the test piece.

As is clear from this result, according to the example, since the electric resistance value is increased proportionally and largely due to the increase in the load applied to the test piece, the electric resistance can be easily increased even when the load is low. It can be detected as a change in resistance value. Further, even at a high load level, the load level can be detected at the same time by measuring the electric resistance value. Therefore, by using the test piece of the example as a sensor as the structure itself or as a part of the structure, the risk of destruction is detected in a wide load range with high sensitivity, and fine-grained destruction prevention measures can be taken. It will be possible.

[Brief description of the drawings]

FIG. 1 is a schematic view of a partial cross-sectional structure of a test piece of an example.

FIG. 2 is a diagram showing an entire test piece of an example.

FIG. 3 is a graph showing a load-deflection-electric resistance change curve of an example.

FIG. 4 is a graph showing a load-deflection-electrical resistance change curve of Comparative Example 1.

5 is a graph showing a load-deflection-electric resistance change curve of Comparative Example 2. FIG.

[Explanation of symbols]

 10 test piece 20 carbon powder carrying glass fiber bundle 30 particles of carbon powder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number for FI Technical indication H01B 1/00 7310-4F B29C 67/18 // B29K 105: 20 (71) Applicant 000002299 Shimizu Corporation 1-3-2 Shibaura, Minato-ku, Tokyo (71) Applicant 000003528 Tokyo Rope Co., Ltd. 2-3-14, Nihombashi Muromachi, Chuo-ku, Tokyo (72) Inventor Hiromichi Kondo Higashi-ku, Higashi-ku, Nagoya, Aichi Shinmachi No. 1 Chubu Electric Power Co., Inc. (72) Inventor Ikutaro Kumazaki Higashi-ku, Nagoya, Aichi Prefecture Higashi Shinmachi No. 1 Chubu Electric Power Co., Inc. No. 1 Fine Ceramics Center Foundation (72) Inventor Masayuki Takada 2-4-1 Rokuno, 4-chome, Atsuta-ku, Nagoya, Aichi Prefecture Fine Ceramics Foundation (72) Inventor Hiroaki Yanagida 1-3-9, Sasu-cho, Chofu-shi, Tokyo (72) Inventor Norio Muto 1-6-6 Moto-Akasaka, Minato-ku, Tokyo Comprehensive Security Co., Ltd. (72) Invention Minoru Sugita 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Hiroshi Takagi 2-3-3, Nihombashi Muromachi, Chuo-ku, Tokyo Tokyo Tuna Steel Co., Ltd.

Claims (9)

[Claims] 1. A molded body containing conductive powder, wherein a conductive phase containing conductive powder is provided integrally with the molded body so as to be able to measure the energized state. 2. The conductive powder-containing compact according to claim 1, wherein the conductive powder is carbon powder and / or ceramic powder. 3. The electroconductive powder-containing compact according to claim 1 or 2, wherein the compact is a plastic material. 4. The conductive powder-containing molded body according to claim 1, wherein a fiber bundle is arranged along the conductive phase. 5. A concrete material comprising the conductive powder-containing compact according to any one of claims 1 to 4. 6. A glass fiber plastic material for concrete reinforcement, comprising a conductive phase containing a conductive powder that can be measured in an energized state integrally along a glass fiber bundle. 7. A conductive state of the conductive phase of the conductive powder-containing molded body according to claim 1 or the structure containing the conductive powder molded body according to claim 1 to 4 is measured. A load detecting method for a molded body or a structure, comprising: 8. A method for detecting a load on a concrete material as claimed in claim 5, which comprises measuring the energized state of the conductive phase. 9. A concrete material comprising the glass fiber plastic material for concrete reinforcement according to claim 6,
A method for detecting a load on a glass fiber reinforced concrete material, which comprises measuring an electrified state of the conductive phase.