JPH1045447A - Short fiber for reinforcement of matrix material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mix short fibers in a matrix material at a high mixing ratio and to improve the reinforcing effect by winding or folding reinforcing short fibers for a matrix material and temporarily sticking at least a part of the fibers with an adhesive comprising a water-soluble resin. SOLUTION: Short fibers 2 of a synthetic fiber for reinforcement of a matrix material are wound or folded to decrease the apparent aspect ratio and are temporarily fixed in at least a part of the fibers with a water-soluble resin adhesive 10 to obtain reinforcing short fibers for a matrix material. The obtd. reinforcing short fibers are mixed by 0.2 to 10.0vol.% into a matrix material comprising a mortar or cement concrete.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short fiber for reinforcing a matrix material, and in particular, can be mixed in a high ratio into a matrix material such as concrete or mortar.
The present invention relates to a matrix material reinforcing short fiber that can enhance the reinforcing effect of a material.

[0002]

2. Description of the Related Art Steel fiber reinforced concrete is known as a concrete composite material in the fields of construction and civil engineering. The steel fiber reinforced concrete is a composite material in which short steel fibers as a reinforcing material are dispersed and mixed in concrete as a matrix material. The steel fibers are distributed evenly in the matrix, and the distributed steel fibers bear the tensile force in the cross section to improve the dispersibility of cracks and restraint,
The toughness, bending strength and tensile strength, which are the basic properties of concrete, can be greatly improved. As the steel fiber, a drawn steel wire having a circular or square cross section of about 0.2 to 0.5 mm (or one side) and having a length If of about 30 to 50 mm is used. As a material of the steel wire, a drawn wire of ordinary steel is generally used, but stainless steel is used in a portion where a rust prevention effect is expected.
It is known that the larger the ratio of fiber length to diameter (lf / φ: aspect ratio) of the steel fiber to be mixed, the higher the tensile strength of the matrix.

[0003] Conventionally, since steel fibers are handled as loose pieces, a disperser or the like is used to efficiently disperse and mix a large amount of steel fibers into concrete as a matrix material. . However, even if a dispersing machine is used, as shown in FIG. 5 (a), the steel fibers 50 may be entangled with each other and formed into a ball-like state and then charged into a mixer (not shown) to form a so-called fiber ball. Many. In addition, when kneading, the steel fiber 50 in the form of a fiber ball embraces the mortar component 51 as shown in FIG. Therefore, in order to eliminate the entanglement between the steel fibers 50 during kneading, as shown in FIG. 6, a large number of steel fibers 50 are aligned in a plate shape, and a water-soluble adhesive 52 is formed between the steel fibers 50. A plate-like steel fiber 55 temporarily fixed at the above has also been developed. When this plate-like steel fiber 55 is used, each steel fiber 50 does not form a fiber ball because the steel fiber 50 is integrally formed into a plate shape when the steel fiber is charged, and each of the steel fibers 50 is formed by water added at the kneading stage. The adhesive 52 between the steel fibers 50 dissolves and adheres, and can be uniformly dispersed in concrete by kneading and stirring.

[0004] Usually, the steel fiber 50 is a drawn thin steel wire, but in order to enhance the reinforcing effect, a steel fiber 50 having a wavy shape or having hooks at both ends has been developed. The reinforcing effect of the steel fibers increases almost in proportion to the volume mixing ratio of the steel fibers. However, the volume mixing ratio of 2% or more is affected by the orientation state and the dispersion state of the steel fibers between the coarse aggregates. It is also known that if it exceeds, the reinforcing effect corresponding to the mixed amount of steel fiber cannot be obtained.

[0005]

Incidentally, the steel fiber hardly bends or bends during kneading, and remains straight. In addition, as shown in FIG. 6, there is a case where a hook 53 or the like is provided at an end portion, and the workability of concrete tends to decrease. For this reason, there is a problem that sufficient compaction cannot be performed at the time of casting and a tensile strength corresponding to the amount of mixed steel fibers cannot be obtained. When the aspect ratio is increased, the steel fibers cannot be sufficiently dispersed in the matrix material in the ordinary kneading process. For this reason, troubles such as hose blockage may occur during the pumping by the concrete pump. Therefore, it is necessary to reduce the maximum diameter of the coarse aggregate or shorten the length of the steel fiber.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, so that the workability does not deteriorate even at a high volume mixing ratio, and a sufficient reinforcing effect can be obtained even at a low volume mixing ratio. And a short fiber for reinforcing a matrix material.

[0007]

In order to achieve the above object, the present invention provides a linear short fiber mixed and dispersed at a predetermined volume mixing ratio in a matrix material to bear a tensile force in a cross section. In a matrix material reinforcing short fiber for improving the bending tensile performance of the matrix material, the short fiber is wound or folded so that an apparent aspect ratio becomes small, and at least a part of the short fiber is an adhesive of a water-soluble resin. And mixed in the matrix material in a state of being temporarily fixed.

[0008] Specifically, a matrix material which improves the bending tensile performance of the matrix material by applying a tensile force in the cross section by linear short fibers mixed and dispersed at a predetermined volume mixing ratio in the matrix material. In the reinforcing short fiber, the short fiber forms a short cylindrical body wound in a ring shape, and at least a part of the short cylindrical body is temporarily fixed with an adhesive of a water-soluble resin, and in the matrix material. It is characterized by being mixed.

[0009] Further, a short fiber for matrix material reinforcement, in which bending shortage performance of the matrix material is improved by bearing a tensile force in the cross section by linear short fibers mixed and dispersed at a predetermined volume mixing ratio in the matrix material. In the fiber, the short fiber forms a folded plate-like body, and at least a part of the plate-like body is temporarily fixed with an adhesive of a water-soluble resin, and mixed in the matrix material. It is.

[0010] The above-mentioned matrix material is preferably cement mortar or cement concrete. At this time, the volume mixing ratio of the short cylindrical body and the plate-like body is preferably set to about 0.2 to 10.0%.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a short fiber for reinforcing a matrix material according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing each form of synthetic fiber short fibers (hereinafter, referred to as short fibers) for reinforcing a matrix material of the present invention. FIG. 1 (a) shows a short fiber wound densely in a cylindrical spiral having a diameter of about 5 mm, and an adhesive 10 attached to three places on its outer periphery to form a ring or coil (hereinafter referred to as a short cylindrical body). )). In the present embodiment, vinylon fibers composed of monofilaments having a diameter of 14 μm are used as the fibers to be used. Short cylindrical body 1
As shown in FIG. 2, is manufactured by cutting out a semi-finished product 3 wound in a long ring shape showing a part thereof to a predetermined length. In this embodiment, one cut short cylindrical body 1 (FIG. 1A) is formed by winding the short fiber 2 for six turns, and has a total length of about 90 mm when unwound. . As a modified example, when a short fiber having a diameter of about 0.2 to 0.8 mm is used, the aspect ratio of the short cylindrical body 1 varies depending on the relationship with the entire length of the short fiber.
It is preferable to change the diameter of the short tubular body so that the tubular length can be suppressed. Further, the shape is not limited to the cylindrical shape, and may be formed into a substantially spherical shape by rounding short fibers. The rounded short fibers are even smaller than the cylinder.

The vinylon fiber described in the present embodiment is a general term for polyvinyl alcohol-based synthetic fibers, and the synthetic fibers usable for the short tubular body 1 include polypropylene, polyacrylonitrile, polyethylene, and other fibers made of cement. It is also preferable from the viewpoint of alkali resistance against the FIG.
(B) shows a form in which the entire short cylindrical body 1 is immersed in an adhesive in a container (not shown) and the whole is covered with an adhesive 10. As the adhesive 10, a water-soluble adhesive is used. As the water-soluble adhesive, a polyvinyl alcohol resin is preferable. The degree of saponification of the polyvinyl alcohol resin is preferably about 60 to 80%, and it is preferable that the adhesive portion can be released by the concrete mixing water. Also,
In addition to polyvinyl alcohol (PVA), water-soluble resins such as polyethylene oxide (PEO), carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxyl propyl cellulose (HPMC), hydroxyl ethyl cellulose (HEC) or polyvinyl pyrrolidone (PVP) Can be used as an adhesive. In addition, by appropriately setting the type of the adhesive, the application amount, the application position, and the like described above, the short fibers that have been wound, folded, or rolled can be reliably returned to their original lengths during kneading. it can.

That is, as shown in FIG.
When the force (arrow A) that spreads both ends of the short fiber 2 acts while the resin of the adhesive 10 temporarily fixing the short fibers 2 is melted by water, the short fiber 2 becomes almost the original length. It will be extended like a close line. At this time, since the short fibers 2 are flexible, the short fibers 2 are bent into an arbitrary shape in the cement paste between the coarse aggregates 15 indicated by phantom lines. Therefore, the reinforcing material has a three-dimensional random orientation. In this regard, when the short cylindrical body 1 is mixed at the same mixing ratio as in the conventional case where steel fibers are mixed, the material strength ratio is slightly reduced. However, since the short cylindrical body 1 when the mixer is charged has a considerably small aspect ratio, no fiber ball is formed even if the mixing ratio is increased. Therefore, the material strength can be increased in proportion to the mixing ratio up to a considerably high volume mixing ratio. In addition, since the short cylindrical body 1 may have a very light unit weight, when the short cylindrical body 1 of the present invention is mixed into a matrix material, for example, the limit volume mixing ratio is 10.0% in the case of concrete. Can be increased to a degree. Since fiber balls are not formed even with such a high volume mixing ratio, during concrete pumping,
There is no need to worry about troubles such as hose blockage.

Here, the mechanism by which the short tubular body 1 mixed in the mixer is unwound and the short fibers 2 are distributed between the coarse aggregates will be described. First, the coarse aggregate 15, the fine aggregate 16, the cement 17, the admixture 18, and the short cylindrical body 1 weighed in a predetermined mixture are put into a mixer (not shown), and are emptied for a predetermined time so that the respective materials are sufficiently mixed. It is kneaded (FIG. 4A).
The kneading water is put into the kneaded material and stirred. When the water spreads throughout the material, the resin of the adhesive 10 that temporarily fixed the short fibers 2 in a ring shape is melted, and the short fibers 2 are restored to their original length due to sliding with the coarse aggregate 15 and the cement paste that are moved by stirring. (FIG. 4 (b)). The short fibers 2 of the present invention have a total length of about 90 mm, and are distributed among a plurality of coarse aggregates, and a three-dimensional random orientation state is formed.

In the above description, the short fibers 2 are bonded with the adhesive 10 in order to form the short tubular body 1. However, in addition to this method, the short fibers 2 may be wound or folded by a predetermined method. Can be formed. FIG. 1C shows a modified example in which the short fibers 2 are bound by resin staples 11 instead of the adhesive 10. The resin staple 11 is made of the above-mentioned polyvinyl alcohol resin, and a part thereof is dissolved by the action of the mixing water. This allows
The short fibers 2 can easily be linearly extended. Also,
FIG. 1D shows an example in which one short fiber 2 is formed into a plate shape which is folded at a predetermined width. In this example, as shown in the figure, the short fiber 2 was folded, and the surface of the short fiber 2 was coated with an adhesive 10 in the form of a narrow band to obtain the plate-like body 5. As described above, when the apparent aspect ratio is reduced by winding or folding the short fibers 2 into a cylindrical shape or a plate shape, the short fibers 2 can be distributed evenly throughout the kneading of the matrix material. Furthermore, the fiber reinforced state illustrated in FIG. 4B can be formed by unwinding the wound fiber from the distributed state.

In the above description, ordinary concrete has been described as a matrix material into which short fibers are mixed, but cement mortar or thermosetting resin such as polyester resin may be used. Various short fibers may be used as long as they are flexible enough to be wound into a ring shape. For example, it is also possible to wind glass fibers, carbon fibers, and aramid fibers into a ring shape.

[0017]

As is apparent from the above description, according to the present invention, since the dispersibility at the time of kneading is good, the mixing ratio of the reinforcing fibers can be increased, and a small mixing ratio is sufficient. Since an increase in strength is obtained, there is an effect that the reinforcing effect of the matrix material can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a plurality of embodiments of a matrix material reinforcing short fiber according to the present invention.

FIG. 2 is an explanatory view showing an example of a method for producing the matrix material reinforcing short fibers shown in FIG. 1 (a).

FIG. 3 is a schematic explanatory view schematically showing a state in which a short cylindrical body is linearly extended.

FIG. 4 is an explanatory view showing a mechanism in which short cylindrical bodies are distributed between coarse aggregates.

FIG. 5 is an explanatory view showing an example of a fiber ball formed of a conventional steel fiber.

FIG. 6 is a perspective view showing a steel fiber temporarily fixed to a plate shape with a water-soluble adhesive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Short cylindrical body 2 Short fiber 5 Plate 10 Adhesive

Claims (5)

[Claims] 1. A reinforcing material for a matrix material, in which a linear short fiber mixed and dispersed at a predetermined volume mixing ratio in a matrix material to bear a tensile force in a cross section to improve the bending tensile performance of the matrix material. In the fiber, the short fiber is wound or folded so as to reduce an apparent aspect ratio, and is mixed in the matrix material in a state where at least a part thereof is temporarily fixed with an adhesive of a water-soluble resin. Short fibers for reinforcing a matrix material. 2. A reinforcing material for a matrix material, wherein a linear short fiber mixed and dispersed at a predetermined volume mixing ratio in a matrix material bears a tensile force in a cross section to improve the bending tensile performance of the matrix material. In the fiber, the short fiber forms a short tubular body wound in a ring shape, and at least a part of the short tubular body is temporarily fixed with an adhesive of a water-soluble resin and mixed in the matrix material. Short fibers for reinforcing a matrix material. 3. A reinforcing material for a matrix material, in which a linear short fiber mixed and dispersed at a predetermined volume mixing ratio in a matrix material to bear a tensile force in a cross section to improve the bending tensile performance of the matrix material. In the fiber, the short fiber forms a folded plate-like body, and at least a part of the plate-like body is temporarily fixed with an adhesive of a water-soluble resin, and mixed in the matrix material. Short fibers for material reinforcement. 4. The short fiber for reinforcing a matrix material according to claim 1, wherein the matrix material is cement mortar or cement concrete. 5. The short fiber for reinforcing a matrix material according to claim 2, wherein the volume mixing ratio is 0.2 to 10.0%.