JP7329666B2 - Fiber-reinforced composite materials for reinforcing concrete, concrete structures - Google Patents

Description

The present invention relates to a fiber-reinforced composite material for reinforcing concrete and a concrete structure containing the same.

Concrete is often used for structures such as pillars, houses, and high-rise buildings. When concrete is used for a building, strength is insufficient with concrete alone. Therefore, in order to reinforce the strength of the concrete, a reinforcing material is arranged inside the concrete. Concrete with a reinforcing material includes, for example, reinforced concrete with reinforcing bars in the core and steel fiber reinforced concrete with metal fibers mixed therein.

When atmospheric carbon dioxide penetrates into concrete, it neutralizes. As the neutralization of concrete progresses, metals constituting reinforcing bars and metal fibers arranged inside the concrete are likely to rust. When rust occurs inside concrete, cracks occur in the concrete. Furthermore, if the concrete contains metal fibers, the metal fibers have very sharp edges, and there is a risk of injury to workers from the metal fibers. For these reasons, reinforcements have been devised to replace metals. Examples of reinforcing materials that can replace metal include carbon fibers.

As a technique for blending carbon fibers into concrete, for example, it is known to blend carbon fibers obtained by adding a sizing material such as an epoxy resin in an amount of 0.1% by mass or more and 10% by mass or less to a cement-based inorganic material. (See Patent Document 1, for example).

In addition, as a technology for blending carbon fibers into concrete, epoxy resin is applied to carbon fiber bundles in which 12,000 carbon fibers are bundled, and the content of carbon fiber single yarns in the fiber strands is 85% by mass or more and 99.8% by mass. % and mixing the carbon fiber strands with concrete to obtain carbon fiber reinforced concrete (see, for example, Patent Document 2).

JP-A-9-110486 JP-A-11-79804

However, the carbon fiber to which the sizing material is applied in an amount of 0.1% by mass or more and 10% by mass or less, or the carbon fiber bundle in which 12000 carbon fibers are bundled, is added with an epoxy resin, and the content of carbon fiber single yarn in the fiber strand is Carbon fiber strands with a content of 85% by mass or more and 99.8% by mass did not have sufficient anchoring force to concrete.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fiber-reinforced composite material for reinforcing concrete and a concrete structure including the same, which has a high anchoring force to concrete.

In order to solve the above problems, the present invention has the following configurations.
[1] A linear product containing a bundle of reinforcing fibers and a thermoplastic resin,
The reinforcing fiber bundle is a bundle of 1000 or more and 10000 or less reinforcing fiber single fibers,
The thermoplastic resin is a thermoplastic epoxy resin,
A fiber-reinforced composite material for reinforcing concrete, having a fiber volume content (Vf value) of 20% or more and 40% or less.
[2] The fiber-reinforced composite material for reinforcing concrete according to [1], wherein the thickness of the cross section in the direction perpendicular to the length direction of the fiber-reinforced composite material for reinforcing concrete is 0.1 mm or more and 3 mm or less. .
[3] The fiber-reinforced composite material for reinforcing concrete according to [1], wherein the reinforcing fibers are carbon fibers.
[4] The fiber-reinforced composite material for reinforcing concrete has a length in the length direction of 10 mm or more and 100 mm or less, and has a shape in which the whole is continuously bent in a wave shape alternately along the length direction [1] ] The fiber-reinforced composite material for reinforcing concrete according to .
[5] A concrete structure comprising a concrete material containing the fiber-reinforced composite material for reinforcing concrete according to any one of [1] to [4].
[6] The concrete structure according to [5], wherein the content of the fiber-reinforced composite material for concrete reinforcement in the concrete material is 1 kg/m ³ or more and 350 kg/m ³ or less.

ADVANTAGE OF THE INVENTION According to this invention, the fiber reinforced composite material for concrete reinforcement which has the high fixation force with respect to a concrete material, and a concrete structure containing the same can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the shape of the fiber-reinforced composite material for reinforcing concrete of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the shape of the fiber-reinforced composite material for reinforcing concrete of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the shape of the fiber-reinforced composite material for reinforcing concrete of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the shape of the fiber-reinforced composite material for reinforcing concrete of the present invention. FIG. 2 is a schematic diagram showing irregularities, concave portions, or convex portions formed on the surface of the fiber-reinforced composite material for reinforcing concrete of the present invention. FIG. 2 is a schematic diagram showing recesses formed on the surface of the fiber-reinforced composite material for reinforcing concrete of the present invention. FIG. 2 is a schematic diagram showing irregularities or protrusions formed on the surface of the fiber-reinforced composite material for reinforcing concrete of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the fixability evaluation method of a fiber reinforced composite material and a concrete material in an Example, (a) is sectional drawing, (b) is a perspective view.

Embodiments of the fiber-reinforced composite material for reinforcing concrete of the present invention and a concrete structure including the same will be described.
It should be noted that the present embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified.

[Fiber-reinforced composite materials for reinforcing concrete]
The fiber-reinforced composite material for reinforcing concrete (hereinafter referred to as "fiber-reinforced composite material") of the present embodiment is a linear material containing a bundle of reinforcing fibers and a thermoplastic resin.
That is, the shape of the fiber-reinforced composite material of the present embodiment is linear and elongated.

A fiber-reinforced composite material is used by blending it in a concrete composition.
In addition, in the fiber-reinforced composite material of the present embodiment, the concrete is not limited to those obtained by mixing sand, gravel, cement, water, etc. Also includes

The reinforcing fibers contained in the fiber-reinforced composite material of the present embodiment are appropriately selected from the group of reinforcing fibers described later, and among these reinforcing fibers, carbon fibers are preferred.

The thermoplastic resin contained in the fiber-reinforced composite material of the present embodiment is appropriately selected from the group of thermoplastic resins described later, and thermoplastic epoxy resins are preferred among them.

The fiber reinforced composite material of the present embodiment preferably has a fiber volume content (Vf value), that is, a content of reinforcing fibers of 10% or more and 70% or less.
If the fiber volume content (Vf value) is 10% or more, the strength of the reinforcing fibers contained in the fiber-reinforced composite material can be reflected in the fiber-reinforced composite material. On the other hand, if the fiber volume content (Vf value) is 70% or less, high fixing power between the thermoplastic resin and the concrete material can be maintained.
In addition, from the viewpoint of being able to impart excellent strength to a concrete structure obtained by blending a fiber-reinforced composite material, the fiber volume content (Vf value) is preferably 15% or more and 50% or less. More preferably, it is 20% or more and 40% or less.

The fiber volume content (Vf value) in the fiber-reinforced composite material of this embodiment can be calculated by the following formula (1).
Vf value (%)=(W−ρ3×V)/[(ρ2−ρ3)×V]×100 (1)

In the above formula (1), W is the mass (g) of the fiber-reinforced composite material, V is the volume of the fiber-reinforced composite material (cm ³ ), and ρ2 is the density of the reinforcing fibers contained in the fiber-reinforced composite material (g/cm ³ ), ρ3 represents the density (g/cm ³ ) of the thermoplastic resin contained in the fiber-reinforced composite material.

The fiber-reinforced composite material of the present embodiment preferably has a cross-sectional thickness of 0.1 mm or more and 3 mm or less, more preferably 0.1 mm or more and 2 mm or less, in a direction perpendicular to the length direction of the fiber-reinforced composite material. is more preferably 0.3 mm or more and 1.5 mm or less, and most preferably 0.5 mm or more and 1.2 mm or less.
If the cross-sectional thickness of the fiber-reinforced composite material in the direction perpendicular to the length direction is 0.1 mm or more, the fiber-reinforced composite material has sufficient mechanical strength and is less likely to break during handling. Therefore, the handleability is improved. On the other hand, if the cross-sectional thickness of the fiber-reinforced composite material in the direction perpendicular to the length direction is 3 mm or less, the contact area between one reinforcing fiber contained in the fiber-reinforced composite material and the concrete material increases. Therefore, it is possible to improve the mechanical strength of concrete structures containing fiber-reinforced composite materials.

In addition, in the fiber-reinforced composite material of the present embodiment, when the shape of the cross section in the direction perpendicular to the length direction of the fiber-reinforced composite material is not circular, the major axis (longest part) of the cross section is taken as the thickness. . Examples of cross-sectional shapes include circular, elliptical, triangular, quadrangular (rectangular), polygons with five or more sides, and star.
When the shape of the cross section is triangular, the long sides of the triangle should satisfy the thickness range described above.

The length in the longitudinal direction of the fiber-reinforced composite material of the present embodiment is preferably 10 mm or more and 100 mm or less, more preferably 20 mm or more and 80 mm or less, and even more preferably 25 mm or more and 60 mm or less.
If the length of the fiber-reinforced composite material in the longitudinal direction is 10 mm or more, the contact area between one fiber-reinforced composite material and the concrete material increases, and sufficient fixing force between the concrete material and the fiber-reinforced composite material is exhibited. and improve the mechanical strength of concrete structures containing fiber-reinforced composite materials. On the other hand, if the length of the fiber-reinforced composite material in the longitudinal direction is 100 mm or less, it becomes easier to mix the fiber-reinforced composite material into the concrete composition, and the fiber-reinforced composite material is less likely to break during mixing, and the concrete composition The fiber-reinforced composite material can be sufficiently dispersed and blended in the article.

The shape (outer shape) of the fiber-reinforced composite material blended in the concrete composition and the fiber-reinforced composite material contained in the concrete material is not particularly limited as long as it is linear, and may be of any shape. The shape of the fiber-reinforced composite material includes, for example, a linear shape as shown in FIG. 1(a); a tape shape; a twisted shape;

A twisted shape is a shape in which a linear fiber-reinforced composite material is given a twist such as being twisted in the axial direction. The twisted shape includes a twisted yarn shape, a coil shape, and the like. The strength and number of twists are not particularly limited.

A bent shape is a shape obtained by bending a linear fiber-reinforced composite material to give an angle, as shown in FIGS. 1(b) to 4(f). The number of points at which the fiber-reinforced composite material is bent, the angle at which the fiber-reinforced composite material is bent, and the length of the bent portion of the fiber-reinforced composite material are not particularly limited.
The bent shape of the fiber-reinforced composite material includes, for example, a shape in which one end is bent in an L shape as shown in FIG. 1(b), and one end as shown in FIGS. A shape in which the part is bent in a substantially L shape (a shape in which the corners of the L shape have a curvature), a shape in which one end is bent in a U shape as shown in FIG. A shape in which one end is bent in a semicircular shape as shown in FIG. 2B and a shape in which one end is bent in a spiral shape as shown in FIGS. A shape in which one end is alternately bent in an acute angle or right angle continuously along the length direction, a shape in which both ends are bent in an L shape as shown in FIG. ) in which both ends are bent in a curved shape (the directions of the curves are opposite to each other), and as shown in FIG. are in the same direction), a shape in which both ends are bent in a semicircular shape as shown in FIG. As shown in FIG. 3( e ), the center part is bent into a square shape as shown in FIG. 3( e ). Shape, as shown in FIG. 3(f), a shape in which the central part is continuously bent in a wave shape alternately along the length direction, and as shown in FIG. 4(a), the whole is along the length direction A shape that is continuously bent in a wave shape, a shape that is alternately bent in an acute angle or a right angle continuously along the length direction as shown in FIG. 4(b), FIG. As shown in FIG. 4(e), the whole is continuous along the length direction and alternately bent in a wave shape, and as shown in FIG. 4(f), the whole is continuous along the length direction. For example, a shape bent alternately in a U-shape may be mentioned.

Moreover, the bent shape may be formed uniformly by a machine or the like, or may be formed unevenly by hand. The bent portion of the fiber-reinforced composite material may have an angle such as a right angle, an acute angle, or an obtuse angle, or may have a curvature to form a gentle curve.

The shape of the fiber-reinforced composite material is preferably linear or curved, more preferably curved. Among curved shapes, wavy shapes are particularly preferred.
If the shape of the fiber-reinforced composite material is a corrugated shape, the fixing force between the fiber-reinforced composite material and the concrete composition will be stronger.

The temperature at which the fiber-reinforced composite material is shaped as described above is not particularly limited. The fiber-reinforced composite material may be deformed by heating, or may be deformed at room temperature.

As shown in FIGS. 5(a) to 7(b), the fiber-reinforced composite material of the present embodiment may, for example, have unevenness on the surface, or may have recesses such as cuts on the surface. Alternatively, a convex portion may be provided on the surface. The shapes of the unevenness, the recesses and the protrusions may be straight lines or curved lines. The direction in which the surface of the fiber-reinforced composite material is cut may be longitudinal (parallel) to the length direction of the fiber-reinforced composite material, or may be transverse to the length direction of the fiber-reinforced composite material ( perpendicular), or oblique to the longitudinal direction of the fiber-reinforced composite material. Concavities and convexities, concave portions and convex portions may be provided continuously or intermittently.

As a fiber-reinforced composite material having unevenness on the surface, for example, as shown in FIG. The surface 10a of the fiber-reinforced composite material 10 is formed to have continuous unevenness.
As a fiber-reinforced composite material having recesses on its surface, as shown in FIG. 5(b), there is a fiber-reinforced composite material 20 in which a plurality of approximately cross-shaped recesses 21 are formed at intervals on a surface 20a. .
As the fiber-reinforced composite material having unevenness on the surface, for example, as shown in FIG. linear (stripe) concave portions 31 are formed, and unevenness is continuously provided on the surface 30a of the fiber-reinforced composite material 30 .

As a fiber-reinforced composite material having unevenness on the surface, for example, as shown in FIG. , and the surface 40a of the fiber-reinforced composite material 40 is provided with continuous unevenness.
As a fiber-reinforced composite material having recesses on its surface, as shown in FIG. A multiple-formed one is mentioned.
As a fiber-reinforced composite material having recesses on its surface, as shown in FIG. 5( f ), a plurality of linear recesses 61 are formed at intervals along the length direction on a surface 60 a of a fiber-reinforced composite material 60 . There are other things.

As a fiber-reinforced composite material having recesses on its surface, as shown in FIG. 6A, a plurality of linear recesses 71 are spaced apart obliquely with respect to the length direction on a surface 70a of a fiber-reinforced composite material 70. formed ones.
As a fiber-reinforced composite material having concave portions on its surface, as shown in FIG. 6(b), a fiber-reinforced composite material 80 in which concave portions 81 are continuously formed in a wavy shape along the length direction on a surface 80a. is mentioned.

As a fiber-reinforced composite material having protrusions on its surface, as shown in FIG. 7A, granular resin is applied to a surface 90a of a fiber-reinforced composite material 90 at intervals, and protrusions 91 made of the resin are obtained. are formed at intervals.
As a fiber-reinforced composite material having convex portions on its surface, as shown in FIG. and a plurality of protrusions 101 made of the resin are formed at intervals.
As a fiber-reinforced composite material having convex portions on its surface, as shown in FIG. 7(c), a resin is applied to the surface 110a of a fiber-reinforced composite material 110 in a spiral shape along the length direction and around the entire circumference. , on which convex portions 111 made of the resin are formed.

As a fiber-reinforced composite material having unevenness on the surface, as shown in FIG. 7(d), resin is continuously applied to the entire outer periphery along the length direction on the surface 120a of the fiber-reinforced composite material 120 in a wave shape. and a plurality of protrusions 121 and recesses 122 made of the resin are formed.
As a fiber-reinforced composite material having convex portions on its surface, as shown in FIG. 7(e), a resin is applied in a spherical shape on the surface 130a of the fiber-reinforced composite material 130 in a direction perpendicular to the length direction and on the entire outer circumference. and a plurality of protrusions 131 made of the resin are formed at intervals.
As a fiber-reinforced composite material having convex portions on its surface, as shown in FIG. are formed at intervals.

Examples of methods for forming unevenness and recesses include the following methods. A method of forming unevenness and recesses according to the shape of the opening of a die when applying a thermoplastic resin to a bundle of reinforcing fibers, a method of applying a thermoplastic resin to a bundle of reinforcing fibers, and then applying a cutter or the like to the surface of the fiber reinforced composite material. A method of forming cuts in a mold, a method of pressurizing or heating and pressurizing a fiber-reinforced composite material using a mold such as a mold to form unevenness and recesses, and a granular resin on the surface of the fiber-reinforced composite material. A method of applying a resin.

The cross-sectional shape of the fiber-reinforced composite material of the present embodiment in the direction perpendicular to the length direction is not particularly limited. Examples of the cross-sectional shape of the fiber-reinforced composite material in the direction perpendicular to the length direction include circular, elliptical, triangular, quadrangular, polygonal shapes with five or more strokes, and star shapes. The shape of the cross section in the direction perpendicular to the length direction of the fiber-reinforced composite material is preferably circular. If the cross-sectional shape of the fiber-reinforced composite material in the direction perpendicular to the length direction is circular, the adhesive force of the fiber-reinforced composite material to the surface of the concrete material and the surface area of the fiber-reinforced composite material are well balanced. , the formation of air bubbles in a concrete structure containing a fiber-reinforced composite material can be suppressed.

As the thermoplastic resin contained in the fiber-reinforced composite material of the present embodiment, it is preferable to use a resin that has a high affinity with the reinforcing fibers and the concrete material.

By using a thermoplastic resin, even after molding the fiber-reinforced composite material, the fiber-reinforced composite material can be heated and molded again into an arbitrary shape such as a wave shape or an L-shape.

In addition, by using a thermoplastic resin, the thermoplastic resin adhering to the surface of the reinforcing fiber bundle softens and deforms due to the heat of hydration generated when the cement contained in the concrete composition hardens, and the concrete composition is solidified. When hardened, the concrete material and the fiber-reinforced composite material are fixed in close contact with each other, so that the mechanical strength of the concrete structure containing the fiber-reinforced composite material can be improved.

Examples of thermoplastic resins include, but are not limited to, polyetheretherketone (PEEK), polypropylene, polyethylene, polystyrene, polyamide, ABS resin, acrylic resin, vinyl chloride resin, vinylidene chloride resin, polyphenylene oxide, polyethylene terephthalate, and polysulfone. , polyethersulfone, polyetherimide, polyarylate, epoxy resin, urethane resin, polycarbonate resin, resorcinol resin, and the like.

Among these thermoplastic resins, polyether ether ketone (PEEK), polyethylene, acrylic resin, vinyl chloride resin, chloride Vinylidene resins, epoxy resins, urethane resins, polycarbonate resins and resorcinol resins are preferred, and epoxy resins are particularly preferred. Thermoplastic epoxy resins have excellent adhesion to carbon fiber and concrete materials. In addition, since the thermoplastic epoxy resin can be dissolved in a ketone solvent, it can be recycled by sorting it into each material constituting the fiber-reinforced composite material.

The thermoplastic epoxy resin is preferably a post-reaction type thermoplastic epoxy resin that is reacted after applying the thermoplastic epoxy resin to the reinforcing fiber bundle.
A post-reaction type thermoplastic epoxy resin is a reactive resin that cures by adding a curing agent such as a crosslinking agent, a catalyst, a polymerization initiator, or a polymerization accelerator to initiate or accelerate the reaction. It is a resin that has thermoplasticity even after it has been cured.

In addition, the post-reaction type thermoplastic epoxy resin in the present embodiment includes one that becomes a phenoxy resin after the reaction. When a post-reaction type thermoplastic epoxy resin is used, the thermoplastic epoxy resin penetrates into the bundles of the reinforcing fibers, so that the strength of the reinforcing fibers can be utilized more effectively in concrete structures. As a result, the mechanical strength of concrete structures containing fiber-reinforced composite materials can be increased. In addition, since the thermoplastic epoxy resin has entered the inside of the bundle of reinforcing fibers, when adding water to a concrete composition containing cement, gravel, fiber-reinforced composite materials, etc., is absorbed, an increase in the amount of water to be added can be suppressed, and a decrease in the strength of the obtained concrete material can be suppressed.

Examples of reinforcing fibers contained in the fiber-reinforced composite material of the present embodiment include inorganic fibers, organic fibers, and composites thereof.
Specific examples of reinforcing fibers include carbon fiber, graphite fiber, silicon carbide fiber, boron fiber, glass fiber, basalt fiber, para-aramid fiber, meta-aramid fiber, ultra-high molecular weight polyethylene fiber, polyarylate fiber, poly Paraphenylene benzoxazole (PBO) fiber, polyphenylene sulfide (PPS) fiber, polyimide fiber, fluorine fiber, polyvinyl alcohol (PVA) fiber, polypropylene (PP) fiber, and the like.

It is preferable to use reinforcing fibers that have a high affinity with thermoplastic resins, and among the above reinforcing fibers, carbon fibers are preferable from the viewpoint of being lightweight and having excellent mechanical strength.

Carbon fibers include, for example, polyacrylonitrile (PAN)-based carbon fibers and pitch-based carbon fibers. Among these carbon fibers, PAN-based carbon fibers are more preferable from the viewpoint of the balance of elastic modulus, mechanical strength, and cost.

In the fiber-reinforced composite material of the present embodiment, a bundle of reinforcing fibers obtained by bundling a plurality of monofilaments of reinforcing fibers is used as the reinforcing fibers.
The bundle of reinforcing fibers may be bundled with a sizing agent as long as it is a bundle of two or more single fibers of reinforcing fibers, or it may be bundled without using a sizing agent. good too. From the viewpoint of productivity, the reinforcing fiber bundles are preferably bundled with a sizing agent. When using a sizing agent, it is preferable to use one having a high affinity with the thermoplastic resin. To obtain a fiber-reinforced composite material having excellent strength and stable strength by using a sizing agent that has a high affinity with a thermoplastic resin, thereby making it easier for the thermoplastic resin to impregnate the inside of the bundle of reinforcing fibers. can be done.

The bundle of reinforcing fibers is preferably a bundle of 500 or more and 100,000 or less reinforcing fiber single fibers, and more preferably a bundle of 1,000 or more and 10,000 or less reinforcing fiber single fibers.
If the single fiber of the reinforcing fiber is 500 or more, a fiber-reinforced composite material that can impart sufficient strength to a concrete structure can be obtained. On the other hand, if the single fiber of the reinforcing fiber is 100,000 or less, the fiber-reinforced composite material can be blended into the concrete composition at a sufficient number and density.

Specifically, as a bundle of reinforcing fibers, for example, a product in which 3000 (3K) bundles of carbon fiber monofilaments supplied from a carbon fiber manufacturer are bundled, a product in which 6000 (6K) bundles are bundled, and 12000 (12K) are bundled. Bundled products, 24000 (24K) bundled products, 40000 (40K) bundled products, 50000 (50K) bundled products, 60000 (60K) bundled products, and the like. In the fiber-reinforced composite material of the present embodiment, the bundle of these carbon fibers is a bundle of one or a plurality of carbon fibers depending on the mechanical strength, length and thickness required by the fiber-reinforced composite material, or A fiber divided into an arbitrary number is used.

Specific examples of carbon fiber bundles include Torayca (registered trademark) yarn (T700SC-24000, etc.) manufactured by Toray Industries, Inc., Pyrofil (registered trademark) manufactured by Mitsubishi Chemical Corporation, and Tenax (manufactured by Toho Tenax Co., Ltd.). (registered trademark), or bundles of a plurality of such carbon fiber bundles.
Untwisted yarn, twisted yarn, untwisted yarn, or the like is used as the carbon fiber bundle.

The length of the reinforcing fiber bundle is preferably 10 mm or more and 100 mm or less.
If the bundle length of the reinforcing fibers is 10 mm or more, the fiber-reinforced composite material can exhibit the mechanical strength of the reinforcing fibers. On the other hand, if the length of the reinforcing fiber bundle is 100 mm or less, it is possible to provide a fiber-reinforced composite material with excellent productivity.

The length of the single fiber of the reinforcing fibers forming the bundle of reinforcing fibers is preferably 10 mm or more and 100 mm or less, like the bundle of reinforcing fibers. That is, it is preferable that the length of the reinforcing fiber monofilaments constituting the reinforcing fiber bundle is substantially the same as the length of the reinforcing fiber bundle obtained by bundling a plurality of reinforcing fiber monofilaments in one direction. .

According to the fiber-reinforced composite material of the present embodiment, the bundle of reinforcing fibers and the thermoplastic resin are included, and the thermoplastic resin has excellent affinity with the reinforcing fibers and the concrete material. It has excellent fixability and can improve the strength of concrete structures.
Further, according to the fiber-reinforced composite material of the present embodiment, since the thermoplastic resin is included, the heat of hydration generated when the cement contained in the concrete composition containing the fiber-reinforced composite material hardens causes the bundles of the reinforcing fibers to form. When the thermoplastic resin adhering to the surface softens and deforms, and the concrete composition hardens, the concrete material and the fiber-reinforced composite material are firmly fixed together. Therefore, the fiber-reinforced composite material of this embodiment has a high anchoring force to concrete material.
Therefore, according to the fiber-reinforced composite material of this embodiment, it is possible to provide a concrete structure containing the fiber-reinforced composite material having excellent mechanical strength.
Moreover, according to the fiber-reinforced composite material of the present embodiment, since it contains reinforcing fibers other than metal, a worker can work safely in handling a concrete structure containing the fiber-reinforced composite material.

[Concrete structure]
The concrete structure of this embodiment is made of a concrete material containing the fiber-reinforced composite material of this embodiment. That is, the concrete structure of the present embodiment is made of a concrete material containing a fiber-reinforced composite material containing the bundle of reinforcing fibers and a thermoplastic resin.

Concrete materials are made by hardening concrete compositions using water or the like, and are composed of cement, mortar mixed with fine aggregate such as cement and sand, coarse aggregate such as cement and gravel, and sand. Concrete mixed with fine aggregate.

The concrete composition contains cement, coarse aggregate such as gravel, and fine aggregate such as sand, and is blended with known admixtures and admixtures such as fluidizers and water reducing agents as necessary. is.

The cement is not particularly limited, and examples thereof include ordinary Portland cement, high-early-strength Portland cement, and ultra-high-early-strength Portland cement.

The content of coarse aggregate and fine aggregate in the concrete composition is appropriately adjusted according to the mechanical strength required for the intended concrete structure.

The amount of water added to the concrete composition is appropriately adjusted according to the content of cement in the concrete composition, taking into consideration the content of coarse aggregate and fine aggregate in the concrete composition.

The concrete structure of the present embodiment preferably contains 0.10% by volume or more and 20% by volume or less of the fiber-reinforced composite material relative to 100% by volume of the concrete material, and contains 1.0% by volume or more and 15% by volume or less. is more preferable, and more preferably 2.0% by volume or more and 10% by volume or less.
If the content of the fiber-reinforced composite material is 0.10% by volume or more, the concrete structure can be sufficiently reinforced by the fiber-reinforced composite material. On the other hand, if the content of the fiber-reinforced composite material is 20% by volume or less, the fiber-reinforced composite material does not impair the mechanical strength of the concrete structure.

In the concrete structure of the present embodiment, the content of the fiber-reinforced composite material for concrete reinforcement in the concrete material is preferably 1 kg/m ³ or more and 350 kg/m ³ or less, and 10 kg/m ³ or more and 250 kg/m ³ or less. more preferably 25 kg/m ³ or more and 160 kg/m ³ or less.
If the content of the fiber-reinforced composite material for concrete reinforcement in the concrete material is 1 kg/m ³ or more, the concrete structure can be sufficiently reinforced by the fiber-reinforced composite material. On the other hand, if the content of the fiber-reinforced composite material for concrete reinforcement in the concrete material is 350 kg/m ³ or less, it is possible to maintain a balance between the productivity and the mechanical strength of the concrete structure.

According to the concrete structure of the present embodiment, since the fiber-reinforced composite material of the present embodiment is included, it is possible to provide a concrete structure having excellent anchoring force between the fiber-reinforced composite material and the concrete material.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

[Example 1]
Using a bundle of 6000 carbon fibers (6K) as a reinforcing fiber bundle in which a plurality of reinforcing fibers are bundled in one direction, and a thermoplastic resin solution containing a thermoplastic epoxy resin as a thermoplastic resin, A fiber reinforced composite material was produced.
Torayca (registered trademark) T300-6000 manufactured by Toray Industries, Inc. was used as a bundle of 6000 (6K) carbon fibers.
The thermoplastic resin solution includes 100 parts by mass of a thermoplastic epoxy resin (post-reactive resin DENATITE XNR6850V, manufactured by Nagase ChemteX Corporation) and 6.5 parts by mass of a curing agent (DENATITE XNH6850V, manufactured by Nagase ChemteX Corporation). , and 10 parts by mass of methyl ethyl ketone.

A thermoplastic resin solution (viscosity 100 mPa s, B-type viscometer, rotor No. 20, 12 rpm. Toki Sangyo Co., Ltd.) is applied to the carbon fiber bundle while pulling out the carbon fiber bundle from the drum on which the carbon fiber bundle is wound. Company: TVB-15 type viscometer, 20°C).
After that, the carbon fiber bundle to which the thermoplastic resin solution is applied is heat-treated at 150° C. for 20 minutes to react and solidify the thermoplastic resin solution, thereby solidifying a straight line composed of the carbon fiber bundle and the thermoplastic resin. got stuff
Thereafter, the solidified product was cut into lengths of 40 mm to obtain a fiber reinforced composite material having a fiber volume content (Vf value) of 30%.
The resulting fiber-reinforced composite material had a circular cross section in the direction perpendicular to its length direction and a thickness of 1.0 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
A cross section perpendicular to the length direction of the obtained fiber-reinforced composite material was observed at a magnification of 100 using a scanning electron microscope (trade name: S3000H, manufactured by Hitachi Science Systems, Ltd.). It was confirmed that the thermoplastic resin entered into the inside of the.

[Example 2]
In the same manner as in Example 1, a linear solidified product composed of a bundle of carbon fibers and a thermoplastic resin was obtained.
The obtained solidified product was heated again and formed into a wave shape to obtain a fiber-reinforced composite material having a fiber volume content (Vf value) of 30%.
The resulting fiber-reinforced composite material had an elliptical cross-sectional shape in the direction perpendicular to its length direction, and a thickness (length of major axis) of 2.0 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
The cross section of the obtained fiber-reinforced composite material in the direction perpendicular to the length direction was observed at a magnification of 100 using a scanning electron microscope in the same manner as in Example 1. As a result, the thermoplastic resin was confirmed to be included.

[Example 3]
In the same manner as in Example 1, except that 60,000 carbon fibers (60K) were bundled as a reinforcing fiber bundle in which a plurality of reinforcing fibers were bundled in one direction, a linear, 40 mm long, fiber A fiber-reinforced composite material with a volume fraction (Vf value) of 30% was obtained.
Pyrofil TRH50 60M manufactured by Mitsubishi Chemical Corporation was used as the carbon fiber.
The resulting fiber-reinforced composite material had a circular cross section in the direction perpendicular to its length direction and a thickness of 2.5 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
The cross section of the obtained fiber-reinforced composite material in the direction perpendicular to the length direction was observed at a magnification of 100 using a scanning electron microscope in the same manner as in Example 1. As a result, the thermoplastic resin was confirmed to be included.

[Example 4]
Using the same reinforcing fibers and thermoplastic resin solution as in Example 1, a linear fiber-reinforced composite material having a length of 40 mm and a fiber volume content (Vf value) of 50% was obtained.
The resulting fiber-reinforced composite material had a circular cross section in the direction perpendicular to its length direction and a thickness of 0.7 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
The cross section of the obtained fiber-reinforced composite material in the direction perpendicular to the length direction was observed at a magnification of 100 using a scanning electron microscope in the same manner as in Example 1. As a result, the thermoplastic resin was confirmed to be included.

[Example 5]
In the same manner as in Example 1, a linear solidified product composed of a bundle of carbon fibers and a thermoplastic resin was obtained.
The resulting solidified product was heated again in the same manner as in Example 2 and formed into a corrugated shape to obtain a fiber-reinforced composite material having a fiber volume content (Vf value) of 50%.
The resulting fiber-reinforced composite material had an elliptical cross-sectional shape in the direction perpendicular to its length direction, and a thickness (length of major axis) of 1.9 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
The cross section of the obtained fiber-reinforced composite material in the direction perpendicular to the length direction was observed at a magnification of 100 using a scanning electron microscope in the same manner as in Example 1. As a result, the thermoplastic resin was confirmed to be included.

[Example 6]
Using the same reinforcing fibers as in Example 3 and the same thermoplastic resin solution as in Example 1, a fiber-reinforced composite material having a linear fiber volume content (Vf value) of 50% was obtained.
The resulting fiber-reinforced composite material had a circular cross section in the direction perpendicular to its length direction and a thickness of 2.4 mm.
A fiber-reinforced composite material having a length of 1.2 mm was prepared separately as a sample for the pull-out test.
The cross section of the obtained fiber-reinforced composite material in the direction perpendicular to the length direction was observed at a magnification of 100 using a scanning electron microscope in the same manner as in Example 1. As a result, the thermoplastic resin was confirmed to be included.

[Evaluation of fixability]
One end of the fiber-reinforced composite material obtained in Examples 1 to 6 was fixed to a concrete material as follows.
As shown in FIG. 8A, a first polypropylene tape (silicone adhesive tape manufactured by Lintec) 300 was wound around the outer periphery of one end 200A of the fiber-reinforced composite material 200. As shown in FIG.
The first PP tape 300 was provided to prevent the fiber-reinforced composite material 200 from being fixed to the concrete material 700 over a predetermined length.
As shown in FIG. 8( a ), from the upper surface 300 a of the wound first PP tape 300 , the outer circumference of the fiber reinforced composite material 200 is spaced 20 mm along the length direction of the fiber reinforced composite material 200 . Then, a second polypropylene tape (hereinafter referred to as "second PP tape") 400 having the same composition as the first PP tape was wound.
The second PP tape 400 was provided to prevent the fiber-reinforced composite material 200 from being fixed to the concrete material 700 over a predetermined length.
As shown in FIG. 8( a ), a silicone cap 500 was attached to the outer circumference of the wound second PP tape 400 .
The silicone cap 500 was provided to prevent stress from concentrating on the fiber-reinforced composite material 200 on the upper surface 700 a of the concrete material 700 .
The fiber-reinforced composite material 200 provided with the first PP tape 300, the second PP tape 400 and the silicone cap 500 in this manner is placed so that one end 200A is vertically downward as shown in FIG. 8(a). embedded in the concrete composition 600 prior to solidification.
After that, the concrete composition 600 was solidified to form a concrete material 700, and the one end portion 200A of the fiber-reinforced composite material 200 and the portion provided with the second PP tape 400 and the silicone cap 500 were fixed to the concrete material 700.
Fixability between the fiber-reinforced composite material 200 and the concrete material 700 was evaluated by performing a pull-out test of the fiber-reinforced composite material 200 from the concrete material 700 .
A pull-out test was performed using a universal testing machine (UH-100kNI) manufactured by Shimadzu Corporation in accordance with the adhesion strength test method between continuous fiber reinforcement and concrete by pull-out test (JSCE-E 539-2007). Ta.

Concrete composition 600 was used by placing mortar comprising cement, fine aggregate and water into square columns of 100 mm×100 mm×100 mm.
Portland cement was used as the cement.
The formulation of Concrete Composition 600 is shown in Table 1.

Table 2 shows the results of the pull-out test of the fiber-reinforced composite materials obtained in Examples 1-6.

In Examples 1, 2, and 5, the fiber-reinforced composite material at the portion not embedded in the concrete material was broken.
In Examples 3, 4 and 6, the fiber-reinforced composite material was removed from the concrete material. Observation of the fiber-reinforced composite material removed from the concrete material revealed that the interface between the concrete material and the thermoplastic resin had separated.

From the results of the fiber reinforced composite material pull-out test in Examples 1 to 6, the fiber reinforced composite material with a small fiber volume content (Vf value) (high thermoplastic resin content) has a longer length. Similarly, it was found that the fixability to the concrete material is superior to that of the fiber-reinforced composite material having a large fiber volume content (Vf value). It was also found that the corrugated fiber-reinforced composite material is superior to the linear fiber-reinforced composite material in fixability to the concrete material.

Also, in Example 3, the amount of reinforcing fibers was ten times that of Example 1, but the tensile strength was only improved by about two times. From these results, it was found that the amount of reinforcing fibers contained in the fiber-reinforced composite material is preferably small, and the fiber-reinforced composite material is preferably thin, from the viewpoint of increasing strength and production costs.

The fiber-reinforced composite material for concrete reinforcement of the present invention not only has excellent durability, but also contributes to improvement of workability such as reduction of burden on workers and improvement of safety, and can contribute to improvement of work efficiency. , its industrial applicability is great.

10,20,30,40,50,60,70,80,90,100,110,120,130,140,200... fiber reinforced composite material , 81, 122... recesses, 91, 101, 111, 121, 131, 141... protrusions, 300... first PP tape, 400... second PP tape, 500... Silicone cap, 600 Concrete composition, 700 Concrete material.

Claims (6)

A linear material containing a bundle of reinforcing fibers and a thermoplastic resin,
The reinforcing fiber bundle is a bundle of 1000 or more and 10000 or less reinforcing fiber single fibers,
The thermoplastic resin is a thermoplastic epoxy resin,
A fiber-reinforced composite material for reinforcing concrete, having a fiber volume content (Vf value) of 20% or more and 40% or less. The fiber-reinforced composite material for reinforcing concrete according to claim 1, wherein the fiber-reinforced composite material for reinforcing concrete has a cross-sectional thickness of 0.1 mm or more and 3 mm or less in a direction perpendicular to the length direction. The fiber-reinforced composite material for reinforcing concrete according to claim 1, wherein the reinforcing fibers are carbon fibers. 2. The fiber-reinforced composite material for reinforcing concrete has a longitudinal length of 10 mm or more and 100 mm or less, and has a shape in which the whole is continuously bent in a wavy shape alternately along the length direction. fiber reinforced composites for concrete reinforcement. A concrete structure comprising a concrete material containing the fiber-reinforced composite material for reinforcing concrete according to any one of claims 1 to 4. The concrete structure according to claim 5, wherein the content of the fiber-reinforced composite material for concrete reinforcement in the concrete material is 1 kg/m3 or ^more and 350 kg/ ^m3 or less.

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