KR101887815B1 - bundle-type short fibers for fiber reinforced concrete using conjugate fiber and fiber Reinforced concrete using thereof - Google Patents

Abstract

The present invention relates to a bundle-type short fiber (1) for reinforcing concrete for increasing compressive strength and flexural tensile strength by being added to a concrete composition to enhance interfacial adhesion, flowability and dispersibility. The bundle-type short fiber (1) for reinforcing concrete is manufactured by twisting para-aramid composite fibers or carbon fiber filaments through a twisting process or covering process, heat-treating the fibers through a resin impregnation process, and then cutting the same. Further, the present invention relates to a fiber reinforced concrete composition in which a bundle-type short fiber (1) for reinforcing concrete is mixed to enhance compressive strength and flexural tensile strength.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a bundle-type short fiber reinforced concrete (CBF)

The present invention relates to a concrete reinforcing short fiber incorporated in a concrete matrix. In particular, the present invention relates to a concrete reinforcing fiber for reinforcing a concrete to improve the mechanical properties of a fiber reinforced concrete composition by improving interfacial adhesion, flowability, The present invention relates to a bundle type short fiber for use in the present invention. For this purpose, the bundle-type short fibers for reinforcing concrete are made of para-aramid composite fibers or carbon composite fibers, and are provided with a twist, and the resin is impregnated with the resin to form a bundle, To bundled short fibers.

Concrete, which is the most commonly used construction material, is cemented by mixing cement, aggregate and sand together with water and hydration reaction. In this case, concrete cracks due to firing, drying shrinkage cracking and hydration heat. Also, concrete has disadvantages that it is fragile due to low tensile strength and strain. Recently, the use of fiber reinforced concrete (FRC) with fiber as a reinforcing material has been increasing steadily to overcome the disadvantages of such concrete. That is, it is known that the FRC has an increased mechanical property and an effect of reducing firing and drying shrinkage cracks.

The FRC contains discontinuous fibers within the concrete matrix, which fibers generally enhance the FRC's appearance. The reinforcement stiffeners incorporated in the concrete matrix suppress the cracks in the concrete and compensate the behavior of the materials after cracking. As the above-mentioned concrete reinforcing staple fibers, steel fiber, synthetic fiber, glass fiber, carbon fiber, asbestos, cellulose fiber and the like are mainly used and there is a great difference in the properties of FRC depending on the type, Therefore, the reinforcing staple fibers should be appropriately selected and used.

The steel fiber has insufficient interfacial adhesion strength to concrete and has a disadvantage that rust occurs due to fiber ball when mixed with concrete. In addition, there is a problem in that the use thereof is restricted in regions where water or salts are abundant, but it has high durability. Glass fiber is degraded in strength due to chemical attack by alkaline components. In addition, asbestos fibers have strong bonding strength with concrete, excellent corrosion resistance and abrasion resistance, but their use as carcinogens is extremely limited.

Recently, the use of synthetic fibers in concrete reinforcing staple fibers has been rapidly increasing. Most synthetic fibers have lower elastic modulus than concrete and are effective in reducing drying shrinkage cracks and improve properties such as impact resistance. Polypropylene fibers with low modulus of elasticity are generally used as synthetic fibers, but nylon fibers and polyethylene fibers are also widely used. Recently, the use of carbon fibers and aramid fibers having high elastic modulus and tensile strength has been increasing, but it has a disadvantage of high cost, in particular, poor interfacial adhesion and dispersibility with concrete matrix.

Korean Patent Laid-Open Publication No. 10-1996-7003393 (filed on August 17, 1996, entitled METAL FIBER COMPOSITION FOR FORMING CONCRETE MEMBERS, PRODUCED MEMBER, AND METHOD OF HEATING THERMAL) And a length of the metal fiber in the range of 1.0 volume% to 4.0 volume%.

Korean Patent Laid-Open No. 10-2008-0061161 (Jul. 02, 2008, entitled "Polyvinyl alcohol staple fiber for cement and concrete reinforcement)", a polyvinyl alcohol (PVA) There is disclosed a polyvinyl alcohol fiber for reinforcing cement and concrete, which can produce a high strength polyvinyl alcohol fiber and can be used as a cement and concrete reinforcing material by producing it as a short fiber to manifest high strength and toughness of a building structure.

The manufacturing process of FRC is similar to the general concrete manufacturing process, but the most important problem is to uniformly disperse the reinforcing staple fibers in the concrete matrix without aggregation. That is, it is known that the mechanical properties of the fiber-reinforced concrete composition, especially the shrinkage of drying shrinkage cracks, are greatly influenced by the dispersibility of the reinforcing staple fibers in the concrete matrix in the production of FRC.

However, in the prior art, the reinforcing short fibers made of polypropylene fibers have a specific gravity of 0.9. When the specific gravity of the reinforcing short fibers is small, the reinforcing short fibers are not properly dispersed in the concrete matrix, In addition, when the specific gravity of reinforcing staple fiber is large, the problem of sedimentation and layer separation in the concrete matrix occurs, so that the physical properties of the concrete composition There is a limit to improvement. In addition, FRC should have excellent bending toughness for crack control, but existing reinforcing staple fibers have limitations in improving it. In addition, reinforcing stiffening fibers having a simple shape structure are weakly interfacial adhesion to a concrete matrix, and their reinforcing function is inferior.

The present invention has been made in order to solve the problems of the prior art as described above. In order to improve the physical properties of the FRC, the present invention provides a method for producing a reinforcing fiber for concrete, The object of the present invention is to provide a bundle-type short fiber for reinforcing concrete having improved interfacial adhesion, flowability and dispersibility when a reinforcing short fiber is formed into a bundle shape by impregnation into a concrete matrix. have. Also, it is an object of the present invention to provide a fiber reinforced concrete composition having a compressive strength of 130 MPa or more and a flexural tensile strength of 15 MPa or more by mixing bundle type short fibers for reinforcing concrete.

The present invention relates to a bundle-type short fiber (1) for reinforcing concrete having improved interfacial adhesion, flowability and dispersibility when mixed in a concrete matrix, and is characterized in that the para- And then cut by heat treatment through a resin impregnation step and then cut into a bundle shape having a bundle shape.

The para-aramid composite fiber is a composite of para-aramid fiber and at least one fiber selected from the group consisting of glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber, slag wool, The fiber is characterized by a composite of carbon fiber and at least one fiber selected from the group consisting of glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber, slag wool. In particular, the para-aramid composite fiber or the carbon composite fiber preferably has a specific gravity of 1.3 to 5.0.

The bundle-type short fibers 1 for reinforcing concrete preferably have a length of 3 to 60 mm, a total fineness of 200 to 6,000 denier, and the resins to be treated in the resin impregnation step include polyvinylidene chloride, Resin, an epoxy resin, a polyurethane resin, and a resorcinol-formalin latex (hereinafter referred to as RFL) resin. Further, the bundle-type short fibers 1 for reinforcing concrete have a twist in the range of 5 to 1,200 T / M in the S direction or Z direction through the twisting process, a twist angle of 42 degrees or less, And 5 to 1,200 T / M in the direction opposite to the first twist yarn direction, and the angle of incidence is 5 to 1,200 T / The twist can be imparted to the twisted yarn at 42 ° or less.

The present invention also relates to a bundle-type short fiber 1 for reinforcing concrete; And a fiber reinforced concrete composition, wherein the fiber reinforced concrete composition has a compressive strength of 130 MPa or more and a flexural tensile strength of 15 MPa or more.

The bundle-type short fibers 1 for reinforcing concrete according to the present invention have an improved interfacial adhesion, flowability and dispersibility when mixed with a concrete matrix by controlling the specific gravity, and also have improved bundle- Thereby preventing the agglomeration phenomenon. Accordingly, the fiber reinforced concrete composition produced by using the bundle-type short fiber 1 for reinforcing concrete has the effect of significantly improving the physical properties, that is, the compressive strength and the flexural tensile strength. Further, by using the bundle-type short fibers 1 for reinforcing concrete according to the present invention, it is possible to increase the construction efficiency of the concrete, improve the workability and shorten the air

1 is a cross-sectional view of a bundle-type short fiber 1 for reinforcing concrete according to an embodiment of the present invention,
Fig. 2 is a schematic view of a twisted filament for explaining the opening angle,
3 is a flowchart showing a manufacturing process of a bundle-type short fiber 1 for reinforcing concrete according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed exemplary embodiments, but is capable of other various forms of implementation. The following examples are intended to be illustrative of the present invention, Is provided to fully inform the user. Also, for convenience of explanation, the components may be exaggerated or reduced in size. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Therefore, the experimental examples of the present invention should not be construed as limited to the specific shapes of the regions shown in this specification, and should include, for example, changes in the shape resulting from manufacturing.

1 is a sectional view of a bundle type short fiber 1 for reinforcing concrete according to an embodiment of the present invention. As shown in FIG. 1, the bundle-type short fiber 1 for reinforcing concrete according to the present invention is a twisted yarn process for imparting twist to improve interfacial adhesion, flowability and dispersibility when mixed in a concrete matrix, After the covering step, the resin impregnation part 20 formed by the resin impregnation step surrounds the fiber 10 so that its cross section has a bundle shape. The bundle shape refers to a shape in which bundles of bundle-type short fibers 1 are bundled together.

The raw material fibers for producing the bundle-type short fibers 1 for reinforcing concrete of the present invention are preferably para-aramid composite fibers or carbon composite fibers.

The para-aramid conjugated fiber refers to a composite fiber obtained by folding at least one fiber selected from the group consisting of para-aramid fiber and glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber and slag wool .

The para-aramid fiber is a kind of aromatic polyamide having a structure in which benzene rings are linearly connected through an amide group (-CONH-). Para-aramid fibers have excellent properties such as high strength, high elasticity and low shrinkage. It has a specific gravity of 1.44 to 1.45, which is advantageous when mixed with a concrete matrix. In particular, it has excellent strength, and is excellent in alkali resistance, acid resistance and chemical resistance.

The carbon composite fiber refers to a composite fiber formed by folding at least one fiber selected from the group consisting of carbon fiber, glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber and slag wool. The carbon fiber is a fiber formed by heating and carbonizing an organic fiber in an inert gas and has a specific gravity of 1.5 to 2.1. The carbon fiber is excellent in heat resistance, impact resistance, resistance to chemicals, and resistance to insects. Also, it has a non-elasticity, a large non-elasticity ratio, light weight, and a property that does not easily deform.

The para-aramid conjugated fiber and the carbon conjugated fiber preferably have a specific gravity of 1.3 to 5.0 in order to improve the dispersibility with the concrete matrix.

As described above, the para-aramid composite fiber or the carbon composite fiber is cut into a predetermined length through a twisting process or a covering process for imparting twist, a resin impregnation process, or the like, and then the bundle of reinforcing concrete ) -Type short fibers (1).

That is, the bundle type short fiber 1 for reinforcing concrete of the present invention imparts twist to the raw fiber to improve interfacial adhesion, flowability and dispersibility when mixed in a concrete matrix. Flowability and dispersibility of the concrete reinforcing staple fibers in the concrete matrix are known to be influenced by the diameter and length of the concrete reinforcing staple fibers and the geometric shape of the fibers. It is also known that the bonding force between the concrete reinforcing stiffener and the concrete matrix is greatly influenced by the interfacial adhesion.

Accordingly, the bundle-type short fibers 1 for reinforcing concrete according to the present invention imparts twist to the raw material fibers to improve interfacial adhesion with the concrete matrix, flowability and dispersibility when incorporated into a concrete matrix.

When the bundle-type short fibers 1 for reinforcing concrete are twisted as described above, the surface area of the bundle-type short fibers 1 for reinforcing concrete is increased to increase the interfacial adhesion force and binding force with the concrete matrix And also improves flowability and dispersibility when incorporated into the concrete matrix. Accordingly, it is preferable that the bundle-type short fibers 1 for reinforcing concrete of the present invention are twisted to the raw fibers through a twisting process or a covering process before the resin impregnation process. The twist imparted by the twisting process is preferably 5 to 1,200 T / M in the S direction or the Z direction, and the twist angle is preferably 42 degrees or less. When the twist applied to the raw fiber is less than 5 T / M, the surface area of the bundle-type short fiber 1 for reinforcing concrete is not greatly increased, so that the interfacial adhesion with the concrete matrix, It is not greatly improved. In addition, when the twist exceeds 1,200 T / M, the fiber exhibits crepe properties, the cutting strength is reduced, and the fibers are deformed to distort the shape, thereby reducing the contact area, Acidity and the like are reduced. Therefore, the twist to be imparted to the raw fiber for producing the bundle-type short fiber 1 for reinforcing concrete through the twisting process is preferably 5 to 1,200 T / M.

The angle of twist provided to the raw fiber is preferably 42 degrees or less. Fig. 2 is a schematic diagram of a twisted filament for explaining the softening angle imparted to the fiber. Referring to FIG. 2, the twist imparted to the fiber by the twisted yarn process can be quantified by measuring the twist angle. That is, as shown in FIG. 2, if a twist is imparted through the twisting process, a spiral winding line is generated in the filament. In this case, the angle between the winding line and the center axis of the yarn is called an angle of view (?), And the size is proportional to the distance (d / 2) from the center axis. In addition, the strength of the twist can be expressed by the magnitude of the angle of incidence, and a stronger twist is given when the angle of incidence is small. The above-mentioned angle of incidence can be calculated by the following equation (1).

[Formula 1]

Further, the twisting imparted in the twisting process may be imparted in the Z direction, which is the twist in the counterclockwise direction, or in the S direction, which is the twist in the clockwise direction. The direction of the twist can be suitably selected by a person skilled in the art.

Particularly, in the present invention, when the angle of twist provided to the raw fiber for producing the bundle-type short fiber 1 for reinforcing concrete is 42 ° or less, the mechanical properties of the fiber-reinforced concrete composition, The strength can be greatly improved.

In another embodiment of the present invention, in order to improve the compressive strength and flexural tensile strength of the fiber reinforced concrete composition, the twist imparted to the raw fiber is 5 to 1,200 T / M in the S direction or Z direction, And the filament of the primary filaments is folded in the direction opposite to the direction of the primary filaments to 5 to 1,200 T / M, and the filament of the primary filaments is doubled to the filament of the filaments of the primary filaments.

In addition, the bundle-type short fibers 1 for reinforcing concrete according to the present invention may be twisted through a covering process. That is, the bundle-type short fibers 1 for reinforcing concrete that have undergone the covering process are increased in surface area to increase the interfacial adhesion with the concrete matrix. In addition, the bundle-type short fibers 1 for reinforcing concrete are formed in a circular shape by the covering step, so that flowability and dispersibility can be improved when they are mixed into the concrete matrix.

As the twisting process or the covering process for imparting twist to the fibers as described above, various known methods can be used.

The total fineness of the raw fiber for producing the bundle-type short fibers 1 for reinforcing concrete of the present invention is preferably 200 to 6,000 denier. When the total fineness of the raw fibers is less than 200 deniers, the dispersion of the fibers in the concrete matrix is easy and workability is good, but the toughness of the fiber reinforced concrete composition after mixing is lowered. In addition, if the total fineness exceeds 6,000 denier, the toughness is increased, but the total fineness should be limited to the above range since the dispersibility is deteriorated.

In addition, the bundle-type short fibers 1 for reinforcing concrete according to the present invention are subjected to a resin treatment by a resin impregnation process in order to improve flowability and dispersibility in a concrete matrix. A bundle-shaped sectional structure in which the resin-impregnated portion 20 surrounds the fiber 10 is formed by the resin impregnation treatment as described above. Since the flowability and dispersibility of the reinforcing staple fibers are greatly influenced by the geometric shape of the fibers when the stiffening short fibers are mixed into the concrete matrix, the cross-sectional shape of the reinforcing fibers is reinforced by the resin impregnation process When formed into a bundle shape, flowability and flowability are improved when mixed in a concrete matrix, and workability is greatly improved.

As described above, in order to improve the flowability of the bundle-type short fiber 1 for reinforcing concrete with the concrete matrix, the resin used in the resin impregnation process may be a polyvinyl resin, an acrylic resin, an epoxy resin, a polyurethane Resin, and resorcinol-formalin-latex (RFL) resin. The resins increase the adhesion of the bundle-type short fibers 1 to reinforcing concrete to the concrete matrix during the treatment, increase the fluidity of the bundle-type short fibers 1 for reinforcing concrete, The effect of improving the flowability and dispersibility is particularly excellent.

After the resin impregnation process, the raw fiber is dried through the heat treatment process. Thereafter, the bundle-type short fibers 1 for concrete reinforcement of the present invention are produced by shortening the fibers through a cutting process.

The length of the bundle-type short fiber 1 for reinforcing concrete according to the present invention formed through the cutting process is preferably 3 to 60 mm. When the length of the bundle-type short fiber 1 for reinforcing concrete is less than 3 mm, the improvement of the physical properties of the fiber-reinforced concrete composition, that is, the compressive strength and the flexural tensile strength after mixing into the concrete matrix is insignificant, , The physical properties are improved when incorporated into the concrete matrix, but the dispersibility is poor due to the occurrence of fiber ball.

The fiber-reinforced concrete composition can be manufactured by a known method using the bundle-type short fiber 1 for reinforcing concrete obtained above. Also, the fiber reinforced concrete composition prepared as described above has a physical property, that is, a compressive strength of 130 MPa or more and a flexural tensile strength of 15 MPa or more.

Hereinafter, a method for manufacturing a bundle-type short fiber 1 for reinforcing concrete according to the present invention will be described. FIG. 3 is a flowchart showing a manufacturing process of a bundle-type short fiber 1 for reinforcing concrete according to an embodiment of the present invention.

As shown in FIG. 3, the bundle-type short fiber 1 for reinforcing concrete of the present invention first prepares para-aramid fiber or carbon fiber multifilament. Wherein at least one fiber selected from the group consisting of para-aramid fiber or carbon fiber multifilament and glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber and slag wool is compounded through a padding process to produce para -Aramid composite fiber or carbon composite fiber is produced. The para-aramid composite fiber or carbon composite fiber prepared as described above is then subjected to a twist through a twisting process or a covering process.

According to a preferred embodiment of the present invention, the method for producing a bundle-type short fiber 1 for reinforcing concrete according to the present invention is characterized in that the para-aramid composite fiber or the carbon fiber composite fiber is subjected to the S- or Z- / M twist through the twisting process. At this time, the angle of twist is preferably 42 degrees or less.

In another embodiment of the present invention, the twist imparted to the para-aramid composite fiber or the carbon fiber composite fiber is 5 to 1,200 T / M in the S direction or the Z direction in the twisting process, , The first multifilaments are folded in the direction opposite to the first twisting direction to 5 to 1,200 T / M, and the twisting angle is set to 42 degrees or less.

The para-aramid conjugated fiber or carbon conjugated fiber to which the twist is imparted as described above is then subjected to a resin impregnation process. Through the resin impregnation process, the cross-sectional shape of the multifilament is produced in a bundle shape. The resin used herein is preferably any one of a polyvinyl resin, an acrylic resin, an epoxy resin, a polyurethane resin, and a resorcinol-formalin-latex (RFL) resin.

At this time, the para-aramid composite fiber or the carbon composite fiber treated with the resin through the resin impregnation step preferably has a specific gravity of 1.3 to 5.0. That is, since the specific gravity of the para-aramid fiber is 1.44 to 1.45 and the specific gravity of the carbon fiber is 1.5 to 2.1, the para-aramid fiber or the carbon fiber can be used as the glass fiber, the basalt fiber, the silica fiber, The bundle-type short fibers 1 for reinforcing concrete according to the present invention may have a specific gravity in the range of 1.3 to 5.0 Adjustable.

That is, in the present invention, when manufacturing a bundle-type short fiber 1 for reinforcing concrete, the para-aramid fiber having a specific gravity of 1.44 and the glass fiber having a specific gravity of 3.0 are combined in a weight ratio of 1: - Aramid composite fibers are produced. The resin impregnation process was performed by impregnating the para-aramid composite fiber having a specific gravity of 1.22 with a PMMA resin having a specific gravity of 1.14 in a weight ratio of 1: 1 to obtain a para-aramid composite fiber having a specific gravity of 1.68, A bundle-type short fiber 1 for reinforcing an aramid-based concrete can be produced. As described above, the bundle-type short fibers 1 for reinforcing concrete according to the present invention can control the specific gravity by controlling the ratio of the composite fibers to the resin to be treated.

When the specific gravity of the bundle-type short fibers 1 for reinforcing concrete according to the present invention is less than 1.3, the specific gravity is small when incorporated in the concrete matrix, so that the short fibers tend to be entangled or aggregated, resulting in poor dispersibility. When the specific gravity of the bundle-type short fiber 1 for reinforcing concrete of the present invention exceeds 5.0, the specific gravity is large, so that it precipitates or layer separation phenomenon occurs when it is mixed into the concrete matrix.

As described above, the para-aramid composite fiber or the carbon composite fiber produced in a bundle through the resin impregnation process is dried to a predetermined length through a cutting process after the impregnated resin is dried through heat treatment to form a short fiber.

The para-aramid composite fiber or the carbon composite fiber produced in the bundling process by the cutting process is made of the bundle-type short fiber 1 for reinforcing concrete of the present invention. As the cutting process, a conventional rotary chopper or the like can be used. At this time, the para-aramid composite fiber or the carbon composite fiber is preferably cut to a length of 3 to 60 mm, and the total fineness of the para-aramid composite fiber or the carbon fiber composite is preferably 200 to 6,000 denier.

The bundle-type short fiber 1 for reinforcing concrete according to the present invention manufactured as described above is used in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of cement as a binder. When the bundle type short fiber 1 for reinforcing concrete is used in an amount of less than 0.5 parts by weight, it is impossible to improve physical properties such as increase in flexural strength and cracking resistance of the concrete composition. When the amount is more than 10 parts by weight, Fiber bundle phenomenon occurs between short fibers due to the incorporation of reinforcing bundle type short fibers (1), so that the strength and durability of the concrete composition are remarkably reduced.

Hereinafter, the present invention will be described in more detail through comparative examples and examples. However, the present invention is not limited to the following examples.

 [Comparative Example]

In order to compare the physical properties of the fiber reinforced concrete composition incorporating the bundle type short fiber 1 for reinforcing concrete according to the present invention, the bundle type short fiber 1 for reinforcing concrete according to the present invention Were prepared as follows and used as test specimens.

(1) Mixing of concrete

The concrete composition was prepared using the same materials as shown in Table 1 below under the conditions as shown in Table 2. < tb > < TABLE >

material sign Properties Silica fume premix cement SFPC Density 3.07 g / cm ³ , specific surface area 6,160 cm ² / g Swelling agent EX Lime, density 3.16 g / m ³ , specific surface area 3,280 cm ² / g Coarse aggregate G Density of 2.64 g / cm ³ , absorption rate of 0.67%, FM 6.74 Fine aggregate S Density 2.61 g / cm < ³ >, absorption rate 1.66%, FM 2.88 Admixture SP Polycarboxylic acid-based high-performance water reducing agent

F.M. : Fineness Modules

W / B (%) Unit weight (kg / m ³ ) W SFPC EX S G SP 16.5 165 919 20 526 839 20

W / B: ratio of water and silica fume premix cement as a binder, W: water

(2) Measurement of physical properties

The compressive strength and flexural tensile strength of the test specimens were measured in accordance with KS F 2505 (Compressive strength test method of concrete) and KS F 2408 (Flexural strength test method of concrete).

[Example 1-15]

In order to investigate the physical properties of the fiber reinforced concrete composition comprising the bundle type short fiber 1 for reinforcing concrete according to the present invention, the concrete of the present invention having the conditions as shown in Table 3 below was used by using para- A reinforcing bundle type short fiber 1 was produced. In Table 3, the conjugate fiber refers to a fiber that is compounded with the para-aramid fiber to be compounded, and the resin refers to the resin used in the resin impregnation process.

In Table 3, PVA refers to polyvinylalcohol as a polyvinyl resin, PMMA refers to polymethylmetacrlate as an acrylic resin, Sorbitol Polyglycidyl Ether as an epoxy resin, and polyurethane resin based on a polyurethane resin (PU), and RFL refers to Resorcinol-Formaline Latex.

The specific gravity of the fiber and the resin used in the present invention is shown in Table 4.

A bundle-type short fiber (1) for reinforcing concrete was mixed with 1.5 parts by weight of 100 parts by weight of the concrete composition of the comparative example to prepare a test piece.

Conjugated fiber Suzy Para-aramid concrete reinforced bundle-type staple fibers Length
(mm) Total fineness
(Denier) kink
(T / M) Twist direction Year angle
(°) importance Example 1 Basalt fiber PVA 10 400 1200 S 41 1.3 Example 2 Silica fiber PVA 20 3,000 200 Z 25 2.2 Example 3 Steel fiber PVA 30 6,000 10 S 8 5.0 Example 4 Glass fiber PMMA 10 400 1200 S 41 1.3 Example 5 Basalt fiber PMMA 20 3,000 200 Z 25 2.1 Example 6 Slab face PMMA 30 6,000 10 S 8 2.1 Example 7 Basalt fiber Sorbitol Polyglycidyl Ether 10 400 1200 S 41 1.3 Example 8 Alumina
fiber Sorbitol Polyglycidyl Ether 20 3,000 200 Z 25 3.0 Example 9 Glass fiber Sorbitol Polyglycidyl Ether 30 6,000 10 S 8 2..0 Example 10 Earlmina
fiber Water-dispersible PU 3 400 1200 S 41 1.3 Example 11 Slab face Water-dispersible PU 20 3,000 200 Z 25 2.1 Example 12 Silica fiber Water-dispersible PU 60 6,000 10 S 8 3.0 Example 13 Basalt fiber RFL 3 400 1200 S 41 1.3 Example 14 Alumina
fiber RFL 20 3,000 200 Z 25 3.0 Example 15 Glass fiber RFL 60 6,000 10 S 8 2.0

fiber importance Suzy importance Para-aramid fiber 1.44 PVA 1.19 Carbon fiber 1.5 PMMA 1.14 Glass fiber 3..0 Sorbitol Polyglycidyl Ether 1.13 Basalt fiber 2.8 Water-dispersible PU 1.07 Silica fiber 1.39 RFL 1.16 Steel fiber 7.3 Alumina fiber 3.965 Slab face 2.7

[Examples 16 to 30]

In order to investigate the physical properties of a fiber reinforced concrete composition comprising a bundle type short fiber (1) for reinforcing concrete according to the present invention, a carbon fiber was used for reinforcing concrete of the present invention Bundled short fibers 1 were prepared. The subsequent steps are the same as in Examples 1-15. That is, since the bundle-type short fibers 1 for reinforcing concrete in Examples 1-15 and Examples 16-30 are produced using para-aramid or carbon fiber, respectively, only the raw fibers are different and the length And the like were used in the same manner.

The properties of the comparative examples and the test pieces of Examples 1-30 were measured and are shown in Table 5.

Conjugated fiber Suzy Carbon fiber-based concrete reinforced bundle-type staple fiber Length
(mm) Total fineness
(Denier) kink
(T / M) kink
direction Year angle
(°) importance Example 16 Basalt fiber PVA 10 400 1200 S 41 1.5 Example 17 Silica fiber PVA 20 3,000 200 Z 25 2.2 Example 18 Steel fiber PVA 30 6,000 10 S 8 5.0 Example 19 Glass fiber PMMA 10 400 1200 S 41 1.5 Example 20 Basalt fiber PMMA 20 3,000 200 Z 25 2.1 Example 21 Slab face PMMA 30 6,000 10 S 8 2.1 Example 22 Basalt fiber Sorbitol Polyglycidyl Ether 10 400 1200 S 41 1.5 Example 23 Alumina
fiber Sorbitol Polyglycidyl Ether 20 3,000 200 Z 25 3.0 Example 24 Glass fiber Sorbitol Polyglycidyl Ether 30 6,000 10 S 8 2..0 Example 25 Earlmina
fiber Water-dispersible PU 3 400 1200 S 41 1.5 Example 26 Slab face Water-dispersible PU 20 3,000 200 Z 25 2.1 Example 27 Silica fiber Water-dispersible PU 60 6,000 10 S 8 3.0 Example 28 Basalt fiber RFL 3 400 1200 S 41 1.5 Example 29 Alumina
fiber RFL 20 3,000 200 Z 25 3.0 Example 30 Glass fiber RFL 60 6,000 10 S 8 2.0

Specimen Compressive strength
(MPa) Flexural tensile strength
(MPa) Specimen Compressive strength
(MPa) Flexural tensile strength
(MPa) Comparative Example 110 9.5 Example 16 133 15.1 Example 1 133 15.2 Example 17 145 15.3 Example 2 137 16.1 Example 18 149 15.3 Example 3 151 17.5 Example 19 135 15.3 Example 4 138 15.6 Example 20 141 15.9 Example 5 142 16.3 Example 21 147 16.1 Example 6 138 17.1 Example 22 131 15.5 Example 7 137 15.2 Example 23 148 15.9 Example 8 142 16.2 Example 24 152 16.2 Example 9 132 17.3 Example 25 135 15.2 Example 10 142 15.8 Example 26 142 15.9 Example 11 143 17.2 Example 27 150 16.1 Example 12 147 18.1 Example 28 135 16.8 Example 13 133 16.9 Example 29 151 17.4 Example 14 141 18.1 Example 30 157 17.8 Example 15 145 19.7

Referring to Table 6, the compressive strength and the flexural tensile strength of the comparative specimens in which the bundle type short fiber 1 for reinforcing concrete according to the present invention was not incorporated were 110 MPa and 9.5 MPa, respectively. However, the compressive strength of the test pieces of Examples 1-15 in which the bundle-type short fibers (1) for reinforcing para-aramid concrete of the present invention were mixed exceeded 130 MPa. That is, the compressive strength of the test specimen of the comparative example prepared without incorporating the bundle-type short fiber 1 for reinforcing concrete of the present invention was 110 MPa, but the compressive strength of the specimen of Example 22 having the lowest compressive strength measurement value The compressive strength of the specimens was measured at 131 MPa. That is, it can be confirmed that the compressive strength of all of Examples 1-15 in which the bundle-type short fiber 1 for reinforcing para-aramid concrete of the present invention is incorporated has a compressive strength of 130 MPa or more.

As for the flexural tensile strength, the flexural tensile strength was measured at 9.5 MPa in the comparative test piece in which the bundle type short fiber (1) for reinforcing para-aramid concrete of the present invention was not incorporated. However, it can be confirmed that the flexural tensile strength of each Example 1-15 in which the bundle-type short fiber 1 for reinforcing para-aramid concrete of the present invention is incorporated has a value of 15 MPa or more.

In Example 16-30 in which the bundle-type short fibers 1 for reinforcing carbon fiber-based concrete of the present invention were incorporated, the compressive strength was all 130 MPa or more and the flexural tensile strength was 15 MPa or more .

That is, it can be seen that the fiber-reinforced concrete composition containing the bundle-type short fiber (1) for para-aramid or carbon fiber reinforced concrete according to the present invention is greatly improved in both compressive strength and flexural tensile strength have. This is because when the bundle type short fiber 1 for reinforcing concrete according to the present invention is mixed, the flowability and dispersibility in the concrete matrix are improved and the interfacial adhesion with the concrete matrix is increased, The compressive strength and the flexural tensile strength of the concrete composition are remarkably improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1: bundle type short fiber for reinforcing concrete, 10: fiber, 20: resin impregnation part

Claims (10)

In a bundle type stiffener for reinforcing concrete having improved dispersibility when mixed with a concrete matrix,
The bundle-type short fibers 1 for reinforcing concrete have a length of 8 to 35 mm, a fineness of 400 to 3,000 denier,
The para-aramid composite fiber having a specific gravity of 1.5 to 3.0 is twisted by a twisting process or a covering process,
The twist is 30 to 400 T / M in the S direction or the Z direction, the angle of inclination is 42 degrees or less,
Treated by a resin impregnation process using any one of polyvinyl resin, acrylic resin, epoxy resin, polyurethane resin, and resorcinol-formalin-latex (RFL) resin and then cut to form a bundle Wherein the bundle-type single-stranded fiber bundle is made of staple fibers.
The method according to claim 1,
Wherein the para-aramid composite fiber is a composite of para-aramid fiber and at least one fiber selected from the group consisting of glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber and slag wool. Bundle-type staple fibers for reinforcement
In a bundle type stiffener for reinforcing concrete having improved dispersibility when mixed with a concrete matrix,
The bundle-type short fibers 1 for reinforcing concrete have a length of 8 to 35 mm, a fineness of 400 to 3,000 denier,
A carbon fiber composite material having a specific gravity of 1.5 to 3.0 is twisted by a twisting process or a covering process,
The twist is 30 to 400 T / M in the S direction or the Z direction, and the twist angle is 42 degrees or less. The filament yarn is firstly twisted and wound in a direction opposite to the first twist yarn direction, 400 T / M, and the angle of rotation is 42 ° or less,
Treated by a resin impregnation process using any one of polyvinyl resin, acrylic resin, epoxy resin, polyurethane resin, and resorcinol-formalin-latex (RFL) resin and then cut to form a bundle Wherein the bundle-type single-stranded fiber bundle is made of staple fibers.
The method of claim 3,
Wherein the carbon composite fiber comprises a carbon fiber bundle, at least one fiber selected from the group consisting of glass fiber, basalt fiber, silica fiber, metal fiber, ceramic fiber, slag wool, (bundle) type short fibers.
delete delete delete delete A bundle-type short fiber for reinforcing concrete according to any one of claims 1 to 4; And concrete. ≪ IMAGE >
The method of claim 9,
Wherein the fiber reinforced concrete composition has a compressive strength of 130 MPa or more and a flexural tensile strength of 15 MPa or more

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