JPH11165311A - Fiber reinforced concrete material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber mesh reinforced concrete material in which a reinforcing effect of a fiber material of a concrete material by a fiber mesh is improved, and in particular, mechanical properties such as flexural strength and flexural toughness are improved, and a method for producing the same. SOLUTION: When producing a concrete material reinforced by a fiber mesh, after the fiber mesh is treated with an uncured epoxy resin, concrete is poured in until the epoxy resin is cured. The concrete material thus obtained is provided with a bending strength improvement of at least 50%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber mesh reinforced concrete material having greatly improved flexural strength and flexural toughness and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the bending strength of a concrete material,
Short fibers such as asbestos fiber, glass fiber, carbon fiber, vinylon fiber, and polypropylene fiber are used as a concrete reinforcing agent to improve the impact strength. In order for the reinforcing short fibers to function effectively in the concrete material, the short fibers need to be uniformly dispersed in the matrix. However, in reality, there are problems such as being restricted by the kneading equipment and the kneading technique being complicated. Further, from the viewpoint of the dispersibility of the short fibers, the length and the amount of the short fibers to be added are limited, and a large reinforcing effect as expected may not be obtained.

[0003] Further, since reinforcing fibers are usually arranged randomly in a matrix, in the case of a material or the like which is designed so that a load is applied only in one direction, all of the short fibers are required for reinforcement. Since it does not contribute effectively, a large reinforcing effect cannot be obtained for the short fiber addition amount. In particular, in the case of a material designed so that a load is applied only in one direction, in order to obtain a large reinforcing effect with a small amount of reinforcing material, reinforcing with long fibers is an effective means. That is, by arranging the long fibers in the tensile direction when stress is applied to the concrete material, it is possible to effectively reinforce.

[0004] Above all, it is widely known that a concrete material is reinforced with a fiber mesh using long fibers. However, the interfacial adhesion performance between the matrix concrete material and the reinforcing material fiber mesh is
Unless some treatment is applied to the fiber mesh, it is not sufficient, and the reinforcing effect as expected is not obtained at present.

Therefore, several attempts have been made to improve the adhesive performance at the interface between the fiber mesh and the concrete material as the matrix. For example, JP
JP-A-2876 discloses a technique in which carbon fibers are coated and impregnated with a mixture of an epoxy resin and silica particles to firmly fix the silica particles on the surface of the fiber mesh. However, in this method, the epoxy resin is cured before casting concrete, so that the resin functions only to fix the silica particles, and only the physical anchor effect by the silica particles contributes to the adhesive force. It is the current situation that relies on.

[0006] Therefore, there is a demand for the development of a technique for further improving the interfacial adhesive strength and the development of a fiber mesh reinforced concrete material having an excellent reinforcing effect.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and improves the reinforcing effect of a concrete material with a fiber mesh.
An object of the present invention is to provide a fiber mesh reinforced concrete material having improved mechanical properties such as flexural toughness and a method for producing the same.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, after treating fibers constituting a reinforcing mesh with an uncured epoxy resin, until the epoxy resin is cured. It has been clarified that mechanical properties such as flexural strength and flexural toughness are significantly improved in concrete materials with concrete poured between them, that is, concrete materials in which the interface between fiber mesh and concrete material is bonded by chemical bonding. did.

Thus, according to the present invention, there is provided a concrete material obtained by reinforcing concrete with a fiber mesh impregnated with an epoxy resin, wherein the concrete material has a flexural strength improvement rate defined by the following formula of 50% or more. In producing a fiber mesh reinforced concrete material, and a concrete material reinforced by the fiber mesh, after the fiber mesh is treated with an uncured epoxy resin, until the epoxy resin is cured. There is provided a method for producing a fiber mesh reinforced concrete material, wherein concrete is poured in between.

[0010]

(Equation 2)

Here, St represents the bending strength of the concrete material reinforced by the fiber mesh treated with the epoxy resin, and Su represents the bending strength of the concrete material reinforced by the fiber mesh not treated with the epoxy resin. .

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention improves the bonding performance at the interface between a concrete material serving as a matrix and a fiber mesh serving as a reinforcing material, and favorably handles the treated fiber mesh. In order to maintain the property, the fiber mesh is subjected to an adhesive treatment with an uncured epoxy resin.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The concrete material in the present invention is not particularly limited as long as it is a mixture in which an aggregate is bound and formed with an inorganic or organic binder as a binder, and a cured product thereof. Concrete materials can be classified by binder, for example, when the binder is inorganic, cement concrete using cement as binder, lime concrete using lime as binder, further plaster concrete, sulfur concrete, etc. Can be mentioned. When the binder is a mixture of an inorganic substance and an organic substance, examples thereof include polymer cement concrete and polymer impregnated concrete. Further, when the binder is organic, resin concrete and the like can be mentioned, and any of them can be used in the present invention. Further, the present invention can also be applied to a system using no aggregate, for example, a cured product of only cement.

Further, the present invention is particularly effective when the concrete material is lightweight cellular concrete (ALC) or the like. This is because, in the case of lightweight cellular concrete, since there are countless cells, it is very effective to reinforce it with long fibers.

The fiber mesh in the present invention means a mesh-like material composed of long fibers, which can generally have a woven structure, a net structure or the like. Can also be applied. The raw yarn constituting the mesh may be either a multifilament composed of a plurality of fiber bundles or a monofilament composed of a single fiber. As the mesh-like material, a material that is molded in a planar shape or three-dimensionally (three-dimensionally) can be used.

The constituent fibers may be either organic fibers or inorganic fibers. Examples of the organic fibers include polyester fibers, nylon fibers, vinylon fibers, aramid fibers, polyarylate fibers, polyethylene fibers, polypropylene fibers, and polyparaphenylene benzobisoxazole fibers. Moreover, if it is an inorganic fiber, a carbon fiber, a glass fiber, a steel fiber, a ceramic fiber, etc. can be mentioned. These fibers may be used alone or in combination. Although various fibers as described above can be used as the fibers constituting the fiber mesh, it is most effective to use aramid fibers. Aramid fibers are not only high in strength and modulus, but also high in toughness, and thus have an excellent reinforcing effect. Of the aramid fibers, the use of copolyparaphenylene / 3,4′-oxydiphenylene terephthalamide fiber, which is remarkably excellent in strength, chemical resistance and wet heat resistance, further enhances the reinforcing effect. In particular, when performing autoclave curing under high temperature and high pressure, copolyparaphenylene / 3,4′-oxydiphenylene terephthalamide fiber having excellent chemical resistance is advantageous.

The epoxy resin used in the present invention may be any epoxy resin having an epoxy group in the molecule. For example, glycidyl ether type, glycidyl ester type, glycidylamine type, linear aliphatic epoxide type and the like can be mentioned. In particular, a bisphenol A type epoxy resin having a high film strength and firmly adhering to a concrete material is most effective. It is preferable to use a curing agent (crosslinking agent) together when performing the bonding treatment with an epoxy resin. The curing agent is not particularly limited, and examples thereof include amines, acid anhydrides, and polyamide resins.

The bonding treatment to the mesh may be carried out with the epoxy resin alone, or the epoxy resin and the inorganic particles may be used in combination. The inorganic particles used in combination with the epoxy resin in the present invention are not particularly limited, and various oxides such as silica, alumina, titanium oxide, antimony oxide, and zirconia can be suitably used.

It is preferable to use the epoxy resin and the inorganic particles in combination because there are at least the following two advantages in terms of practical handling as compared with the case where the epoxy resin is used alone. (1) Since the tack on the mesh surface and the adhesion between the meshes are suppressed, the handleability is higher when winding the fiber mesh after the bonding process or when storing after winding, and then when actually performing the construction. . (2) Since the time-dependent decrease in the adhesive treatment effect due to the progress of the curing with time of the epoxy resin can serve as an anchor effect due to the presence of the inorganic particles or as a reaction point with the concrete matrix, even if the curing with time of the epoxy resin occurs, the bonding is performed. The time-dependent decrease in performance becomes smaller, and the time constraint from the treatment to the production of the reinforced concrete is alleviated, so that the storage from the bonding treatment to the construction can be more easily performed.

When the epoxy resin and the inorganic particles are used in combination to adhere to the mesh, either a single-stage treatment using a mixture of the epoxy resin and the inorganic particles, or a two-stage treatment of treating with the epoxy resin and then treating with the inorganic particles may be used. .

When a curing agent is added to and mixed with the epoxy resin as necessary, it may be selected depending on the type of concrete material to be reinforced. In other words, in the case of a concrete material that cures at a temperature near normal temperature, it is necessary to use an epoxy resin and a curing agent whose curing reaction proceeds at that temperature. Further, in the case of a concrete material to be subjected to steam curing, an epoxy resin and a curing agent whose curing reaction is completely completed at the temperature and time of the steam curing may be selected. Further, when the concrete material is subjected to autoclave curing at a high temperature and a high pressure, an epoxy resin which completely cures at the curing temperature and time may be selected.

In particular, in the case of concrete which is preliminarily cured at a low temperature, such as ALC, and then cured in an autoclave, the epoxy resin is completely cured during the precuring at a low temperature. In some cases, it is better to select a type of resin that does the following. Because the thermal expansion coefficients of the epoxy resin and the reinforcing fibers and concrete materials are generally different, if the epoxy resin cures during autoclave curing at high temperatures, the mesh / concrete composite will be strained after cooling, thus lengthening the length. During the use of the period, cracks may occur.

In order to improve the adhesive strength at the mesh / concrete material interface, when the fresh concrete is combined with the mesh treated according to the present invention, the epoxy group of the epoxy resin applied to the fiber mesh is completely reduced. It is necessary that unreacted or unreacted substances remain. That is, when the fresh concrete and the fiber mesh are combined, the epoxy group in the epoxy resin adhered and impregnated to the fiber mesh has not reacted at all, or the unreacted epoxy group has substantially reacted with the concrete. It is preferable that 50% or more remain when the inorganic particles are not used together, or more than 10% when the inorganic particles are used together. When the residual amount of unreacted epoxy groups is less than 50% when inorganic particles are not used in combination and 10% when inorganic particles are used in combination, adhesion to concrete may be insufficient. Therefore, when the concrete is cast, it is preferable to measure the curing time of the epoxy resin to be used in advance and finish the casting within the time. Further, when the inorganic material is not used in combination, the surface of the treated mesh does not exhibit tackiness when the above-mentioned curing occurs, and this may be used as an approximate standard.

The concrete material after casting the concrete on the fiber mesh is then cured by a conventional method. At this time, it is preferable to select an epoxy resin and a curing agent that complete the curing reaction within the curing temperature and time. In particular, in the case of concrete which is preliminarily cured at a low temperature, such as ALC, and then cured in an autoclave, a type of resin in which the epoxy resin is completely cured at the time of precuring at a low temperature. It is better to select Because the epoxy resin, the fibers constituting the mesh and the concrete material generally have different coefficients of thermal expansion, if the epoxy resin cures during autoclave curing at high temperatures, the mesh / concrete composite material will be strained after cooling. This may cause cracking during long-term use.

Thus, the concrete material in which the concept of chemical adhesion is introduced at the interface with the reinforcing fiber has a flexural strength improvement rate defined by the following formula of at least 50%.

[0026]

(Equation 3)

Here, St represents the bending strength of the concrete material reinforced by the fiber mesh treated with the epoxy resin, and Su represents the bending strength of the concrete material reinforced by the fiber mesh not treated with the epoxy resin.

When the bending strength improvement ratio is less than 50%,
The reinforcing effect of the fiber mesh is not sufficiently exhibited.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the description. In addition, the manufacturing method and the evaluation method of the test piece used in the Example are as follows.

(1) Adhesion treatment to mesh [Adhesion treatment 1] Bisphenol A type epoxy resin (AR bond, sold by Teijin Limited) is amine-coated on a biaxial mesh (fiber pitch: 2 cm) with a constituent denier of 1500 de. The adhesion treatment was performed by uniformly adhering the treatment agent to which the system curing agent was added and mixed. The mesh after the bonding treatment was sealed and stored at 20 ° C. when not immediately used for preparing the following mesh / concrete material composite test piece. This is referred to as bonding processing 1.

Adhesion treatment 2 In the above adhesion treatment 2, a bisphenol A type epoxy resin (Araldite 6099, sold by Asahi Ciba Co., Ltd.), which does not undergo a curing reaction at around room temperature and cures during autoclave curing, is used as the epoxy resin. Except for using, the same operation as in bonding treatment 1 was performed. This is referred to as bonding processing 2.

Adhesion treatment 3 Bisphenol A type epoxy resin (AR Bond, sold by Teijin Limited) and Aerosil # 200 (Nippon Aerosil Co., Ltd.) were applied to a biaxial mesh (fiber pitch: 2 cm) having a denier of 1500 denier. (A silica powder) was mixed at a weight ratio of 5: 1, and then a treatment agent mixed with an amine-based curing agent was uniformly adhered to perform an adhesion treatment. The mesh after the bonding treatment was sealed and stored at 20 ° C. when not immediately used for preparing the following mesh / concrete material composite test piece. This is referred to as bonding processing 3.

Adhesion Treatment 4 In the above-mentioned adhesion treatment 2, bisphenol A type epoxy resin (Araldite 6099, sold by Asahi Ciba Co., Ltd.), which does not undergo a curing reaction at around normal temperature and cures during autoclave curing, is used as the epoxy resin. Except for using, the same operation as in bonding process 2 was performed. This is referred to as bonding processing 4.

Adhesion treatment 5 A biaxial mesh having a fiber denier of 1500 de (fiber pitch: 2 cm) was mixed with a bisphenol A type epoxy resin (AR Bond, sold by Teijin Limited) with an amine curing agent. After uniformly applying the treating agent, Aerosil # 200 (silica powder made by Nippon Aerosil Co., Ltd.) is almost uniformly applied to the mesh by an amount such that the weight ratio with respect to the epoxy resin attached to the mesh becomes 1/5, thereby bonding. Processing was performed. The mesh after the bonding process
When not immediately used for preparing the following mesh / concrete composite material test piece, it was sealed and stored at 20 ° C. This is referred to as bonding processing 5.

(2) Method for Preparing Mesh / Concrete Material Composite Specimen For preparing test pieces, a mesh was combined with the following concrete material at the stage of casting. The mesh is positioned at a position 5 mm from the bottom of the formwork (4 × 4 × 16 cm) so that the warp of the mesh is parallel to the longitudinal direction of the specimen beam and the mesh is parallel to the bottom of the formwork. It was reinforced by putting it in such a way. However, after mixing the epoxy resin and the curing agent, before the curing reaction was completed, they were combined with the concrete material below. This step was performed at two levels immediately after the mesh bonding treatment and seven days later.

(2-a) Method for preparing concrete material 1 (mortar) Ordinary Portland cement, ISO sand, methylcellulose and water were mixed with an omni mixer (model: OM-10-E, capacity:
(10 L, manufactured by GARBRO) at a speed of 400 rpm for about 5 minutes. (Water / cement = 0.45,
(Sand / cement = 0.5) The fresh mortar was poured into a mold (4 × 4 × 16 cm), cured in the air at room temperature for 28 days, and then the bending strength was measured.

(2-b) Method for preparing concrete material 2 (light-weight cellular concrete) Silica, quicklime, cement, gypsum, aluminum powder, reinforcing fiber, water (water / solid weight = 0.65) was mixed with an omni mixer (model: OM-10-E, capacity: 10L, GARBR
(Company O) at a speed of 400 rpm for about 3 minutes to obtain a uniform slurry. This slurry is placed in a mold (4 ×
4 × 16 cm) and about 40 in a state where water does not evaporate
C. for 4 hours for foaming. Subsequently, autoclaving (180 ° C. × 10 hours) was performed to obtain a lightweight cellular concrete specimen. The sheet was air-dried at room temperature, and the bending strength was measured when the moisture content was 10 ± 2%.

(3) Evaluation of handleability of the mesh Immediately after the bonding treatment and immediately before the casting, the mesh was cut out so as to have a weight between 90 g and 100 g, and the mesh was lightly touched with a stainless steel plate having a diameter of 10 cm. The presence or absence of tack, that is, the ease of handling, was evaluated based on whether or not the mesh was lifted even slightly when the stainless plate was lifted.

(4) Measurement of Flexural Strength The flexural strength was measured as if the mesh were arranged in the tensile direction of the specimen. Measurements were taken by centralized shipment. That is, a 10-ton tensile compression tester (UNIVERSAL TESTING INST)
RUMENTMODEL UTM 10t, TOYO
(Made by BALDWIN Co., Ltd.), the center of the fulcrum distance of 10 cm was compressed at a speed of 2 mm / min, and the bending strength was determined from the highest point of stress.

(5) Calculation of Flexural Strength Improvement Rate The flexural strength St of the concrete material when the epoxy resin is adhered and impregnated, and the flexural strength Su of the concrete material when the epoxy resin is not impregnated and impregnated, are measured. It is calculated by the following equation.

[0041]

(Equation 4)

Examples 1 to 7 and Comparative Examples 1 to 4
No. 7 to 7 use aramid fiber (polyparaphenylene-3,4'-oxydiphenylene terephthalamide fiber, Technora T-200, manufactured by Teijin Limited), PAN-based carbon fiber, and vinylon fiber as the mesh constituting raw yarn. Then, evaluation of the adhesive treatment to the mesh and the handling properties of the mesh itself, and preparation of various raw yarn mesh reinforced mortar specimens as described above, measurement of the bending strength, and the results are shown in Table 1.
It was noted in. The mesh shape used, the bonding method, and the like are as described above.

Comparative Example 4 shows no fiber reinforcement (blank; no mesh and no fibers)
Comparative Examples 1 to 3 are cases in which a mesh that was not subjected to an adhesive treatment was used. In the same manner as in Examples 1 to 7, various raw yarn mesh reinforced mortar specimens and reinforced lightweight cellular concrete specimens were prepared. And the bending strength were measured, and the results were simultaneously shown in Table 1.

[0044]

[Table 1]

The following two things can be understood from the above results.
(1) The mesh subjected to the bonding treatment according to the present invention has a large reinforcing effect on the concrete material as compared with the mesh not subjected to the bonding treatment. Further, (2) when a mesh treated with an epoxy resin and an inorganic substance is used in the bonding treatment according to the present invention, the composite material with concrete is more effective than the mesh treated only with the epoxy resin after the bonding operation is completed. It is also possible to extend the time until creation, and the handling is further improved.

[0046]

According to the present invention, bending strength, bending toughness,
A material having excellent mechanical properties such as impact resistance can be obtained. The reason is that the use of the fiber mesh to which the uncured epoxy resin is applied improves the interfacial adhesion performance between the cast concrete material and the mesh, resulting in a large reinforcing effect. Especially when the epoxy resin and the inorganic particles are used together, the tack on the mesh surface and the adhesion between the meshes are suppressed, so when winding the fiber mesh after the bonding process or when storing after winding, and then actually afterwards Because the handleability when performing the construction is higher, and the aging of the adhesive treatment effect due to the progress of the aging of the epoxy resin can serve as the anchor effect due to the presence of the inorganic particles or the reaction point with the concrete matrix, Even if the epoxy resin hardens over time, the decrease in the adhesive performance over time becomes smaller, and the time constraint from the treatment to the production of the reinforced concrete is alleviated, so that the storage from the adhesion treatment to the construction can be more easily performed.

The concrete material having excellent mechanical properties such as flexural strength, flexural toughness and impact resistance proposed by the present invention can be used, for example, as a building material for outer walls and the like, as a permanent form, and for preventing cracking of sprayed concrete. It is also highly useful for preventing falling off.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI D03D 15/00 D03D 15/00 A D04G 1/00 D04G 1/00 Z D06M 11/79 D06M 15/55 15/55 D01F 6 / 60 371Z // D01F 6/60 371 D06M 11/12 (C04B 28/04 16:06) (C04B 28/20 22:04 16:06) 111: 20 D06M 101: 36 (72) Inventor Torukei Matsui Osaka 3-4-1, Amihara, Ibaraki-shi, Japan Teijin Limited Osaka Research Center

Claims (14)

[Claims] 1. A fiber reinforced with a fiber mesh treated with an epoxy resin, wherein the concrete material has a flexural strength improvement rate defined by the following formula of 50% or more. Mesh reinforced concrete material. (Equation 1) Here, St is the bending strength of the concrete material reinforced by the epoxy resin-treated fiber mesh, and
u represents the flexural strength of a concrete material reinforced by a fiber mesh not treated with an epoxy resin. 2. The concrete material according to claim 1, wherein inorganic particles are fixed on the surface of the fibers constituting the mesh. 3. The concrete material according to claim 1, wherein the epoxy resin is a mixture with inorganic particles. 4. The concrete material according to claim 2, wherein the inorganic substance is silica. 5. The concrete material according to claim 1, wherein the fibers constituting the fiber mesh contain aramid fibers. 6. An aramid fiber comprising copolyparaphenylene.
The concrete material according to claim 5, which is 3,4'-oxydiphenylene terephthalamide fiber. 7. The concrete material according to claim 1, wherein the concrete material is lightweight cellular concrete. 8. When producing a concrete material reinforced by a fiber mesh, the fiber mesh is treated with an uncured epoxy resin and then concrete is poured in until the epoxy resin is cured. Of producing a fiber mesh reinforced concrete material. 9. The method for producing a concrete material according to claim 8, wherein inorganic particles are further fixed on the surface of the fibers constituting the mesh. 10. The method according to claim 8, wherein the epoxy resin is a mixture with inorganic particles. 11. The method according to claim 9, wherein the inorganic substance is silica.
A method for producing a concrete material according to any one of the preceding claims. 12. The method for producing a concrete material according to claim 8, wherein the fibers constituting the fiber mesh contain aramid fibers. 13. The method for producing a concrete material according to claim 11, wherein the aramid fiber is copolyparaphenylene-3,4′-oxydiphenyleneterephthalamide fiber. 14. The method for producing a concrete material according to claim 8, wherein the concrete material is lightweight cellular concrete.