JP5939567B2 - Cement reinforcement - Google Patents

Description

  The present invention relates to a cement reinforcement used to reinforce a concrete structure or a mortar structure.

  Concrete and mortar are widely used as materials for solid structures in the civil engineering and construction fields. However, when a vibration caused by an earthquake or an artificial vibration is applied, a crack is generated in such a structure, and the crack spreads over the entire structure, and the durability of the structure is rapidly reduced. In order to cope with such cracks, the surface of the structure may be painted or a sheet may be attached. However, such a countermeasure requires too much labor and cost.

  Therefore, for example, a method of mixing a cement reinforcing material, which is a short fiber for reinforcement having a length of several tens mm, into uncured concrete or mortar for lining (see, for example, Patent Document 1 and Patent Document 2).

Japanese Patent Publication No.58-18343 Japanese Patent Publication No. 60-28775

  In Patent Document 1, a cement reinforcing material obtained by cutting a polyolefin stretched tape that has been embossed into an appropriate length is used, and physical bonding of the cement reinforcing material to concrete or mortar is increased by embossing. Moreover, in patent document 2, the polyvinyl alcohol fiber cut | disconnected for a short time is mixed in cementitious material, and the bending strength and impact strength of cement material are improved.

  By the way, when a short fiber cement reinforcing material is mixed in concrete or mortar, when the reinforcing material is made of resin and has a low density, the reinforcing material floats in the concrete or mortar. On the other hand, when the reinforcing material is made of, for example, steel and has a high density, the reinforcing material settles in concrete or mortar. If a concrete or mortar that is not evenly dispersed due to the rise or sink of the reinforcing material is cast, for example, to produce a structure such as concrete, the reinforcing material does not reach the entire structure. Only the side is reinforced, and the other side cannot secure a sufficient reinforcing effect. In addition, if a large amount of reinforcing material is mixed into concrete or the like for the purpose of improving the overall reinforcing effect, the structure becomes expensive. In the case of a reinforcing material with low density, the surface side of the structure In addition, a large amount of the reinforcing material may be lifted and the appearance may be deteriorated. In addition, if the density of the reinforcing material is large, rebounding at the time of placement becomes a problem, and if the ceiling is covered with a reinforcing material having a low density, the effect of suppressing cracks on the ceiling surface cannot be expected.

  Therefore, there is a limit to the reinforcement of the structure even if only the bonding strength between the reinforcing material and concrete or mortar is increased as in the techniques of Patent Document 1 and Patent Document 2.

  Therefore, an object of the present invention is to provide a cement reinforcing material that can be uniformly dispersed in concrete or the like when mixed in concrete or mortar and can reinforce the structure as a whole at low cost.

In order to achieve this object, the cement reinforcing material of the present invention is a cement reinforcing material that reinforces hardened concrete or mortar by mixing with uncured concrete or mortar, and a hollow portion extending in the length direction is formed. And a density adjusting material having a density different from the density of the short fiber or the material of the short fiber, which is filled or accommodated in the hollow portion. Here, if the density is used a metallic short fibers, for example 7.9~8.9g / cm ^3, the density of the low density such density for example 0.9 g / cm ³ order of molten wax or molten resin Using an adjusting material, the average density of the reinforcing material is made lower than the density of the short metal fibers, and is made to match or approach the density of the concrete or mortar material. Alternatively, when resin short fibers having a density of, for example, about 0.9 g / cm ³ are used, a high density density adjusting material such as metal fibers having a density of, for example, 7.9 to 8.9 g / cm ³ is used. Used, the average density of the reinforcing material is increased more than the density of the resin short fibers, and also matches or approaches the density of the concrete or mortar material. The hollow portion may be opened at both ends in the length direction or may be opened only at one end in the length direction. In some cases, both ends of the hollow portion are closed.

  By the way, it is preferable that the cement reinforcing material has strong bondability with hardened concrete or mortar as well as uniform dispersibility in concrete or mortar. Here, if a cement material is used as the density adjusting material, the setting time of the cement material filled in the hollow portion of the cement reinforcing material and the setting time of the concrete or mortar mixed with the cement reinforcing material can be easily matched. . If it does so, since concrete or mortar and the cement material in a hollow part will be hardened | cured and integrated simultaneously, a cement reinforcement will be firmly combined with concrete or mortar.

  The crack suppression effect of concrete and mortar is improved by increasing the tensile strength of the short fibers of the cement reinforcement, and the tensile strength of the short fibers is increased by increasing the cross-sectional area. However, the rate of increase in the tensile strength of short fibers decreases when the cross-sectional area is increased to some extent, even if the cross-sectional area is further increased. In addition, the effect of suppressing cracking by short fibers tends to decrease as the number of cement reinforcements or short fibers per unit volume of concrete or mortar decreases, so it is not a good idea to increase the size of the short fibers too much. . Therefore, in the “steel fiber reinforced concrete design and construction manual” (issued in 1995 by the Steel Club SFRC Structural Design and Construction Study Group), the length of the reinforcing short fiber is 25 mm to 60 mm and the diameter is 0.3 mm to 0.8 mm. Is specified. The “steel fiber reinforced concrete design and construction manual” is about reinforcing steel short fibers, but it is preferable to use other metal, resin or ceramic short fibers having the same dimensions. And in the hollow part of the short fiber of such a size, it is a liquid or paste-like cement material mixed with aggregates such as concrete and mortar for lining the structure. It is preferable to use those not present. Therefore, cement paste (cement + water, cement + water + admixture) is suitable as a cement material to be filled in the hollow portion of the short fiber. Also, when cement paste (mortar) containing fine aggregate (sand) is used as cement material, the fine aggregate used is compared with that used in mortar for structural lining. A small diameter is preferred. And, in order to fill the cement paste into the hollow portion of such a short fiber having a small diameter, the capillary phenomenon is used, or the short fiber is accommodated in the decompression chamber and the decompression chamber is evacuated, and the evacuated decompression chamber is filled. It is effective to employ a forced filling method such as drawing in the cement paste and filling the hollow part.

  In the present invention, materials other than cement paste can be used as the density adjusting material. For example, a resin fiber having a low density may be inserted or filled into a hollow portion of a high-density metal or ceramic short fiber as a density adjusting material. Alternatively, as already described, a hollow portion of a high-density metal or ceramic short fiber may be filled or accommodated with a low-density molten resin or wax as a density adjusting material. On the contrary, a high density metal or ceramic fiber may be inserted into the hollow portion of the low density resin short fiber as a density adjusting material to be filled or accommodated. Even when a molten resin or a molten wax is used, the molten resin or the molten wax can be filled or accommodated using a capillary phenomenon or a forced filling method.

Concrete and mortar, which are materials for manufacturing structures, are made by adding water to cement and mixing aggregates, and the mixing ratio of cement, water, and aggregates changes depending on the type and use of the structure to be manufactured. Is typically adjusted to a density of (2.6 ± 0.3) g / cm ³ . Therefore, in order to ensure good dispersibility of the cement reinforcing material in the concrete or mortar, the average density of the cement reinforcing material is the density of the concrete or mortar (2.6 ± 0.3) g / cm ^3. It is effective to keep it inside. Accordingly, the density of the short fibers is R ₁ (g / cm ³ ), the inner diameter is D ₁ (cm), the outer diameter is D ₂ (cm), the density of the density adjusting material is R ₂ (g / cm ³ ), and the diameter It is preferable that the cement reinforcing material is configured so as to satisfy the following condition when D ₃ (cm).
2.3 ≦ (R ₁ · D ₂ ² + R ₂ · D ₃ ² −R ₁ · D ₁ ² ) / D ₂ ² ≦ 2.9

When using high-density metal or ceramic short fibers, the hollow part is formed so as to be closed at both ends in the length direction of the short fiber, and air or inert gas is enclosed in the hollow part. You can also keep it. The cement reinforcing material in this case satisfies the following conditions when the density of short fibers is R ₁ (g / cm ³ ), the inner diameter is D ₁ (cm), and the outer diameter is D ₂ (cm). It is preferable.
2.3 ≦ (R ₁ · D ₂ ² −R ₁ · D ₁ ² ) / D ₂ ² ≦ 2.9

  The method for reinforcing concrete or mortar according to the present invention is a method for reinforcing concrete or mortar, and is a fiber for preparing short fibers in which at least one end in the length direction is open and a hollow portion extending in the length direction is formed. A preparation step, a constitution step of filling or containing a liquid or paste density adjusting material having a density different from the density of the short fibers in the hollow portion of the short fibers to constitute a cement reinforcing material, and the constituted cement reinforcing material In a concrete or mortar, which is an uncured structural material, and a reinforcing step for reinforcing the hardened concrete or mortar.

  In the present invention, since the density of the short fiber cement reinforcing material is made to correspond to the density of concrete or mortar, it is possible to provide a cement reinforcing material and a concrete or mortar reinforcing method capable of exhibiting excellent reinforcing strength.

It is a figure which shows the 1st cement reinforcing material which concerns on this invention. It is a figure which shows the manufacturing method of a 1st cement reinforcing material. It is a figure which shows the 2nd cement reinforcing material which concerns on this invention. It is a figure which shows the manufacturing method of a 2nd cement reinforcing material. It is a figure which shows the 3rd cement reinforcing material which concerns on this invention. It is a figure which shows the manufacturing method of a 3rd cement reinforcing material. It is a figure which shows the 4th cement reinforcing material which concerns on this invention. It is a figure which shows the manufacturing method of a 4th cement reinforcing material. It is a figure which shows the 5th cement reinforcing material which concerns on this invention. It is a conceptual diagram explaining the manufacturing method of the 5th cement reinforcing material. It is a figure which shows the 6th cement reinforcing material which concerns on this invention. It is a conceptual diagram explaining the manufacturing method of the 6th cement reinforcing material. It is a figure which shows the 7th cement reinforcing material which concerns on this invention. It is a conceptual diagram explaining the manufacturing method of the 7th cement reinforcing material.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a view showing a first cement reinforcing material according to the present invention, and FIG. 2 is a view showing a manufacturing method of the first cement reinforcing material.

The first cement reinforcing material 1 is cement paste in a hollow portion 5 that is open at one end in the length direction of the polyethylene short fiber 3 and is closed at the other end in the length direction (see reference numeral 4). 7 is filled. In order to manufacture such a first cement reinforcing material 1, for example, a polyethylene short fiber 3 with one side opening cut to 3 cm is accommodated in a decompression chamber 9, and the decompression chamber 9 is evacuated to reduce the pressure. After that (FIG. 2a), the cement pace 7 is drawn into the decompression chamber 9 maintaining the decompressed state, and is filled into the hollow portion 5 of the polyethylene short fiber 3 (FIG. 2b). Note that the surface of the first cement reinforcing material 1 (polyethylene short fibers 3) may be subjected to uneven processing to improve the bond strength with concrete or mortar. As the polyethylene short fibers 3, those having an inner diameter of 0.075 cm, an outer diameter of 0.08 cm and a density of 0.9 g / cm ³ are used, and as the cement paste 7, those having a density of 2.6 g / cm ³ are used. The average density of the first cement reinforcing material 1 is (0.9 × 0.08 ² + 2.6 × 0.075 ² −0.9 × 0. 075 ² ) /0.08 ² = 2.3 g / cm ³ (rounded down to the second decimal place).

  FIG. 3 is a diagram showing a second cement reinforcing material according to the present invention, and FIG. 4 is a diagram showing a method for producing the second cement reinforcing material.

The second cement reinforcing material 11 is configured by filling a cement paste 7 into a hollow portion 15 penetrating in the length direction of a polyethylene short fiber 13. In order to manufacture such a second cement reinforcing material 11, for example, polyethylene short fibers 13 cut to 3 cm are put into a container 17 in which cement paste 7 is placed. Then, the cement paste 7 enters and fills the hollow portion 15 by capillary action (FIG. 4). Note that the surface of the second cement reinforcing material 11 (polyethylene short fibers 13) may be roughened to improve the bond strength with concrete or mortar. As the polyethylene short fibers 13, those having an inner diameter of 0.01 cm, an outer diameter of 0.011 cm and a density of 0.9 g / cm ³ are used, and as the cement paste 7, those having a density of 2.6 g / cm ³ are used. The average density of the second cement reinforcing material 11 is (0.9 × 0.011 ² + 2.6 × 0.01 ² −0.9 × 0.01 ² ) /0.011 ² = 2.3 g / cm ³ (rounded down to the second decimal place).

The first cement reinforcing material 1 and the second cement reinforcing material 11 have a density of 2.3 g / cm ^{3 to 3} by adding coarse aggregate, fine aggregate, early strong Portland cement and water sequentially into a concrete mixer and kneading. When mixed in a building concrete material adjusted to 2.9 g / cm ³ , it uniformly disperses, and the cement cement 7 filled with the concrete material and the hardening time of the concrete material are made to coincide with each other. The bond strength between the second cement reinforcing material 11 and the hardened concrete material is increased.

  Here, polyethylene was used as the material of the short fibers 3 of the first cement reinforcing material 1 and the short fibers 13 of the second cement reinforcing material 11, but polypropylene, polystyrene, polycarbonate, polyacetal, vinylon, PET, aramid, acrylic Other resin materials such as polyamide, polyester, polyurethane, urea resin, melamine resin, polyimide, epoxy resin, and phenol resin can also be used.

  FIG. 5 is a view showing a third cement reinforcing material according to the present invention, and FIG. 6 is a view showing a manufacturing method of the third cement reinforcing material.

The third cement reinforcing material 19 has a molten wax in a hollow portion 23 extending in the length direction that opens at one end in the length direction of the short steel fiber 21 and is closed (see reference numeral 22) at the other end in the length direction. 25. In order to manufacture such a third cement reinforcing material 19, for example, steel short fibers 21 having one side opening cut to 3 cm are accommodated in the decompression chamber 9, and the decompression chamber 9 is evacuated to reduce the pressure. Then (FIG. 6a), the molten wax 25 is drawn into the decompression chamber 9 that maintains the decompressed state, and is filled into the hollow portion 23 of the steel short fiber 21 (FIG. 6b). In addition, the unevenness | corrugation process may be given to the surface of the 3rd cement reinforcing material 19 (steel short fiber 21), and the bond strength with concrete or mortar may be improved. As the steel short fiber 21, one having an inner diameter of 0.07 cm, an outer diameter of 0.08 cm and a density of 7.9 g / cm ³ is used, and as the molten wax 25, one having a density of 0.9 g / cm ³ is used. The average density of the third cement reinforcing material 19 is (7.9 × 0.08 ² + 0.9 × 0.07 ² −7.9 × 0. 07 ² ) /0.08 ² = 2.5 g / cm ³ (rounded down to the second decimal place).

  FIG. 7 is a view showing a fourth cement reinforcing material according to the present invention, and FIG. 8 is a view showing a manufacturing method of the fourth cement reinforcing material.

The fourth cement reinforcing material 27 is configured by filling the hollow wax 31 penetrating in the length direction of the steel short fibers 29 with the molten wax 25. In order to manufacture such a fourth cement reinforcing material 27, for example, steel short fibers 29 cut into 3 cm are put into a container 33 in which molten wax 25 is placed. Then, the molten wax 25 enters and fills the hollow portion 31 by capillary action (FIG. 8). Note that the surface of the fourth cement reinforcing material 27 (steel short fibers 29) may be roughened to improve the bond strength with concrete or mortar. As the steel short fibers 29, those having an inner diameter of 0.012 cm, an outer diameter of 0.014 cm and a density of 7.9 g / cm ³ are used, and as the molten wax 25, those having a density of 0.9 g / cm ³ are used. The average density of the fourth cement reinforcing material 27 is (7.9 × 0.014 ² + 0.9 × 0.012 ² −7.9 × 0.012 ² ) /0.014 ² = 2.7 g / cm ³ (rounded down to the second decimal place).

  Here, although the steel short fibers 21 and 29 are used for the third cement reinforcing material 19 and the fourth cement reinforcing material 27, other metal materials such as stainless steel, copper and brass, zirconia, alumina and the like are used. Ceramic materials can also be used. Further, although the molten wax 25 is used as the density adjusting material, a molten resin can also be used. Polyethylene can be used as the molten resin.

  In addition, formation of the hollow part of one side opening can be performed by using a heating cutter and a non-heating cutter alternately, for example, when cut | disconnecting a short fiber from a long fiber. The heating cutter melts and closes the cut end on the other end side in the length direction of the short fiber.

  FIG. 9 is a diagram showing a fifth cement reinforcing material according to the present invention, and FIG. 10 is a diagram showing a fifth method for producing a cement reinforcing material.

The fifth cement reinforcing material 35 is configured by inserting and filling steel fibers 41 into a hollow portion 39 penetrating in the length direction of polyethylene short fibers 37. In order to manufacture the fifth cement reinforcing material 35, first, the polyethylene fiber tube 43 and the steel fiber 45 are fed out while the small diameter steel fiber 45 is inserted into the polyethylene fiber tube 43 having a large inner diameter. Then, the polyethylene fiber tube 43 is passed through a high-temperature tank 47 (for example, a heating layer of 250 degrees), and the polyethylene fiber tube 43 is thermally contracted to be in close contact with the steel fiber 45. The polyethylene fiber tube 43 integrated with the steel fibers 45 in this way is cut into an appropriate length (for example, 3 cm) with a cutter 49 to form a fifth cement reinforcing material 35 shown in FIG. Note that the surface of the fifth cement reinforcing material 35 (polyethylene short fibers 37) may be subjected to uneven processing to improve the bond strength with the concrete material. The polyethylene fiber tube 43 has an inner diameter of 0.05 cm, an outer diameter of 0.08 cm, and a density of 0.9 g / cm ³ , and the steel fiber 45 has a diameter of 0.04 cm and a density of 7.9 g / cm ^3. Use one. The average density of the fifth cement reinforcing material 35 is (0.9 × 0.08 ² + 7.9 × 0.04 ² −0), since the change in the outer diameter of the polyethylene fiber tube 43 due to heat shrinkage can be ignored. .9 × 0.04 ² ) /0.08 ² = 2.6 g / cm ³ (rounded down to the second decimal place). Here, polyethylene was used as the material of the short fibers 37 of the fifth cement reinforcing material 35, but polypropylene, polystyrene, polycarbonate, polyacetal, vinylon, PET, aramid, acrylic, polyamide, polyester, polyurethane, urea resin, melamine resin. Other resin materials such as polyimide, epoxy resin, and phenol resin can also be used. Moreover, although the thing made from steel is used as the density adjustment material of the 5th cement reinforcement 35, other metal materials, such as stainless steel, copper, and brass, and ceramic materials, such as a zirconia and an alumina, can also be used.

  FIG. 11 is a diagram showing a sixth cement reinforcing material according to the present invention, and FIG. 12 is a diagram showing a sixth method for producing a cement reinforcing material.

The sixth cement reinforcing material 51 is configured by inserting and filling polyethylene fibers 57 into hollow portions 55 penetrating in the length direction of the steel short fibers 53. In order to manufacture such a sixth cement reinforcing material 51, the steel fiber tube 59 and the polyethylene fiber 61 are fed out while inserting the polyethylene fiber 61 into the steel fiber tube 59, and an appropriate length (for example, The sixth cement reinforcing material 51 shown in FIG. Note that the surface of the sixth cement reinforcing material 51 (steel short fiber 53) may be subjected to uneven processing to improve the bond strength with the concrete material. The steel fiber tube 59 has an inner diameter of 0.07 cm, an outer diameter of 0.08 cm, and a density of 7.9 g / cm ³ , and the polyethylene fiber 61 has an outer diameter of 0.065 cm and a density of 0.9 g / cm 3. ^{Use three} . The average density of the sixth cement reinforcing material 51 is (7.9 × 0.08 ² + 0.9 × 0.065 ² −7.9 × 0.07 ² ) /0.08 ² = 2.4 g / cm ³ (rounded down to the second decimal place). Here, the short fiber 53 made of steel is used, but as the material of the short fiber 53 of the sixth cement reinforcing material 51, other metal materials such as stainless steel, copper and brass, and ceramic materials such as zirconia and alumina are used. It can also be used. Polyethylene was used as the density adjusting material, but other materials such as polypropylene, polystyrene, polycarbonate, polyacetal, vinylon, PET, aramid, acrylic, polyamide, polyester, polyurethane, urea resin, melamine resin, polyimide, epoxy resin, phenol resin, etc. These resin materials can also be used.

  FIG. 13 is a diagram showing a seventh cement reinforcing material according to the present invention, and FIG. 14 is a conceptual diagram for explaining a manufacturing method of the seventh cement reinforcing material.

In the seventh cement reinforcing material 65, a hollow portion 69 extending in the length direction of the steel short fiber 67 is closed at both ends (see reference numeral 71), and air or an inert gas is sealed in the hollow portion 69. Is. In order to manufacture the seventh cement reinforcing material 65, a steel fiber tube 75 having a hollow portion 73 penetrating in the length direction is drawn out in an air or inert gas atmosphere, and an appropriate length (for example, 3 cm) is obtained. ) To form a seventh cement reinforcing material 65 shown in FIG. 13 (see cutting point 77). The seventh cement reinforcing material 65 in which both ends of the hollow portion 69 of the steel short fiber 67 are closed can be obtained by cutting with the heating cutter 79 and melting and closing the cut ports at both ends at the time of cutting. . Note that the surface of the seventh cement reinforcing material 65 (steel short fiber 67) may be subjected to uneven processing to improve the bond strength with the concrete material. A steel fiber tube 75 having an inner diameter of 0.065 cm, an outer diameter of 0.08 cm, and a density of 7.9 g / cm ³ is used. The average density of the seventh cement reinforcing material 65 is (7.9 × 0.08 ² −7.9 × 0.065 ² ) /0.08 ² = because the mass of the closed portions on both ends can be ignored. 2.6 g / cm ³ (rounded down to the second decimal place).

More specifically, the first to seventh cement reinforcing materials 1, 11, 19, 27, 35, 51, 65 are, for example, 389 parts coarse aggregate (surface dry specific gravity 2.66) fine aggregate (table Dry specific gravity 2.66) 389 parts, early strength Portland cement (density 3.05 g / cm ³ ) 15 parts, water 7.5 parts sequentially put into a concrete mixer, kneaded for 3 minutes, density 2.3 g / cm ³ to be put into one of the 2.9 g / cm ^3, in which exhibits excellent reinforcing effect.

  The present invention can be used as a reinforcement for concrete or mortar buildings.

DESCRIPTION OF SYMBOLS 1 1st cement reinforcing material 3, 13, 21, 29, 37, 53, 67 Short fiber 5, 15, 23, 31, 39, 55, 69 Hollow part 7 Cement paste (density adjusting material)
11 Second cement reinforcing material 19 Third cement reinforcing material 25 Molten wax (density adjusting material)
27 4th cement reinforcing material 35 5th cement reinforcing material 41 Steel fiber (density adjusting material)
51 6th cement reinforcing material 57 Polyethylene fiber (density adjusting material)
65 Seventh cement reinforcement

Claims (2)

Cement reinforcement that reinforces concrete or mortar after hardening by mixing into uncured concrete or mortar,
A short fiber in which a hollow portion extending in the length direction is formed, and a density adjusting material having a density different from the density of the material of the short fiber filled or contained in the hollow portion,
The short fibers are metal, ceramics or resin, wherein the density adjusting material Ri der cement paste,
The density of the short fiber is R ₁ (g / cm ³ ), the inner diameter is D ₁ (cm), the outer diameter is D ₂ (cm), the density of the density adjusting material is R ₂ (g / cm ³ ), and the diameter A cement reinforcing material characterized by satisfying the following conditions when D ₃ (cm).
2.3 ≦ (R ₁ · D ₂ ² + R ₂ · D ₃ ² −R ₁ · D ₁ ² ) / D ₂ ² ≦ 2.9 Cement reinforcement that reinforces concrete or mortar after hardening by mixing into uncured concrete or mortar,
A short fiber in which a hollow portion extending in the length direction is formed, and a density adjusting material having a density different from the density of the material of the short fiber filled or contained in the hollow portion,
The short fibers are metal or ceramic, the density adjusting material is Ri molten wax der,
The density of the short fiber is R ₁ (g / cm ³ ), the inner diameter is D ₁ (cm), the outer diameter is D ₂ (cm), the density of the density adjusting material is R ₂ (g / cm ³ ), and the diameter A cement reinforcing material characterized by satisfying the following conditions when D ₃ (cm).
2.3 ≦ (R ₁ · D ₂ ² + R ₂ · D ₃ ² −R ₁ · D ₁ ² ) / D ₂ ² ≦ 2.9

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