METHOD FOR MANUFACTURING FIBER COMPOSITE FOR REINFORCING CONCRETE, AND CONCRETE COMPRISING FIBER COMPOSITE MANUFACTURED THEREBY

Abstract

The purpose of the present application is to provide a fiber composite for reinforcing concrete, the fiber composite providing a specific number of twists so as to have pull-out resistance in concrete, being capable of serving as a concrete reinforcement since hydrophilic compound, which can bind to concrete by hydrogen bonding, is coated on concrete and the fiber composite, maintaining the shape of fibers when mixed into concrete, reducing a rebound rate during shotcrete placing, and maintaining linearity within concrete.

Claims

1. A method of manufacturing a fiber composite for reinforcing concrete, the method comprising: twisting two strands of filament yarns for a fiber composite to have turns per meter (TPM) of 200 to 500 to form a helix structure in which 2 strands of yarns form an angle 50 to 100° in an axial direction of the fiber composite from a surface of the fiber composite to prevent reduction in spinning resistance performance; and forming a compound bond between the fiber composite and a coating solution by drying and heat-treating the fiber composite after immersing the fiber composite in a coating solution.

2. The method according to claim 1, further comprising: after the drying and heat-treating the fiber composite, cutting the fiber composite to a length of 10 to 100 mm.

3. The method according to claim 1, wherein the filament yarn for the fiber composite includes one or more filaments selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and polyamide.

4. The method according to claim 1, wherein the twisting includes performing twisting to have total fineness of the fiber composite as 2000 to 4000 denier.

5. The method according to claim 1, wherein the coating solution includes one or more selected from the group consisting of an epoxy compound, polyhydric alcohol, polyhydric phenol, resorcinol-formalin-latex (RFL), and polyvinyl chloride (PVC).

6. The method according to claim 1, wherein the immersing is performed with 0.3 to 4% of solid content in the coating solution based on a weight of the twisted fiber composite.

7. The method according to claim 1, wherein the drying is performed at 100 to 150° C., and the heat-treating is performed at 220 to 250° C.

8. A fiber composite for reinforcing concrete manufactured using the method according to claim 1.

9. A method of constructing a structure or a tunnel, the method comprising: mixing the fiber composite for reinforcing concrete according to claim 8 with shotcrete and constructing a shotcrete layer on a construction surface of the structure or an excavation surface of the tunnel.

10. A concrete structure reinforced with a fiber composite, comprising the fiber composite for reinforcing concrete according to claim 8 in a range of 5 to 20 kg per 1 cubic meter (m3) of concrete.

11. The concrete structure reinforced with a fiber composite according to claim 10, wherein, when measured based on ASTM D885, tensile strength is equal to or greater than 18 kgf, wherein, when measured using a KSF 2566 method, flexural strength of the concrete is equal to or greater than 4.5 MPa, and equivalent flexural strength is equal to or greater than 3.0 MPa.

12. The concrete structure reinforced with a fiber composite according to claim 10, wherein the concrete is shotcrete.

13. A fiber composite for reinforcing concrete comprising a filament yarn for a fiber composite, wherein, when measured based on ASTM 2256, initial modulus of the fiber composite is 30 g/d to 110 g/d, and a rebound amount of the fiber composite is reduced compared with modulus greater than 110 g/d while concrete including the fiber composite for reinforcing concrete is poured.

14. The fiber composite for reinforcing concrete according to claim 13, wherein a helix structure is formed on a surface of the fiber composite.

15. The fiber composite for reinforcing concrete according to claim 13, wherein the fiber composite is maintained to have linearity in concrete.

16. The fiber composite for reinforcing concrete according to claim 13, wherein the filament yarn for the fiber composite includes one or more filaments selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and polyamide.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0050] FIG. 1 is a schematic diagram showing injection using an injector of shotcrete in which a conventional fiber composite is mixed.

[0051] FIG. 2 is a schematic diagram. showing injection. using an injector of shotcrete in which a fiber composite according to the present disclosure is mixed.

BEST MODE

[0052] Hereinafter, exemplary embodiments are presented to help understanding of the present disclosure. However, the following examples are provided for those skilled in the art to more easily understand the present disclosure, and content of the present disclosure is not limited by the examples.

EXAMPLE 1

[0053] Two strands of 1500 denier polyethylene terephthalate (PET) yarns were used to manufacture raw cord through secondary twist (cable twist)/primary twist (ply twist) with 390/390 TPM, and the raw cord was woven using a weaving machine. Then, a fiber composite was manufactured by immersing the result in an epoxy compound, primarily drying the result at 150° C. for 60 seconds, and then secondarily heat-setting the result at 230° C. for 60 seconds. A concrete structure test piece was manufactured by removing weft after cutting the manufactured fiber composite to a length of 50 mm and putting 11 kg of the fiber composite into 1 cubic meter (m.sup.3) of concrete having a water content of 43%.

EXAMPLE 2

[0054] Example 2 was the same as Example 1 above except that 9 kg of the fiber composite was put into 1 m.sup.3 of concrete.

EXAMPLE 3

[0055] Example 3 is the same as Example 1 above except that the fiber composite was cut to a length of 40 mm.

EXAMPLE 4

[0056] Example 4 was the same as Example 1 above except that the raw cord was immersed in a resorcinol-formalin-latex (RFL) compound.

Comparative Example 1

[0057] Comparative Example 1 was the same as Example 1 above except that 3 kg of the fiber composite was put into 1 cubic meter (m.sup.3) of concrete.

Comparative Example 2

[0058] Comparative Example 2 was the same as Example 1 above except that the fiber composite was cut to a length of 20 mm.

Comparative Example 3

[0059] Comparative Example 3 was the same as Example 1 above except that secondary twist (cable twist)/primary twist (ply twist) had 100/100 TPM when manufacturing the raw cord.

Comparative Example 4

[0060] Comparative Example 4 was the same as Example 1 above except that the fiber composite was coated with an olefin-based resin as a hydrophobic resin when manufacturing the fiber composite.

Comparative Example 5

[0061] Comparative Example 5 was the same as Example 1 above except that a fiber composite with modulus of 280 g/d was manufactured using polyethylene naphthalate (PEN) yarns and used.

[0062] Table 1 (shows the physical properties of the fiber composites for reinforcing concrete and the physical properties of the concrete structures, the fiber composites and the concrete structures being manufactured in Examples 1 and 2, etc.)

TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 Fiber composite 22.5 22.5 22.5 22.5 22.5 22.5 23.2 22.7 22.9 strength (kgf) Modulus (g/d) 80 80 80 80 80 80 117 80 280 Flexural 4.7 4.5 4.61 4.53 3.98 3.99 4.6 4.51 4.72 strength (MPA) Equivalent flexural 3.53 3.12 3.24 3.15 1.8 2.0 2.1 2.4 3.32 strength (MPA) Rebound rate (%)* 0.8 0.8 0.8 0.8 0.8 0.8 3.5 0.8 8.9 *Rebound rate refers to the amount of bounce compared to an input amount during shotcrete construction.
As seen from Table 1 above, in Comparative Example 1, a low amount of the fiber composite is put compared with the condition of Example 1, and thus concrete reinforcement performance is degraded to lower the flexural strength and the equivalent flexural strength of the concrete structure. It may be seen that, in Comparative Example 2, the length of the fiber composite is reduced compared with the condition of Example 1, and thus equivalent flexural strength is much degraded from the result of checking the reinforcement performance. It may be seen that, in Comparative Example 3, turns per meter (TPM) of the fiber composite is reduced to 100/100 TPM compared with the condition of Example 1, and thus friction (spinning resistance) of the concrete and the fiber composite is lowered to degrade the equivalent flexural strength of the concrete structure.

[0063] It may be seen that, in Comparative Example 4 in which the fiber composite was coated with an olefin-based resin as a hydrophobic resin that blocks hydrogen bonding between the fiber composite and the concrete, the equivalent flexural strength is also lowered. It may be seen that, in Comparative Example 5, when the fiber composite with high modulus is used, the amount of fiber composite bounced out rather than inside the concrete during construction increases, and thus the rebound amount remarkably increases.

[0064] For reference, the flexural strength and the equivalent flexural strength are the same as described above, and a measurement method thereof is in accordance with KSF 2566.

[0065] The above description of the present disclosure is for illustration, and those of ordinary skill in the art to which the present disclosure pertains can easily change the present disclosure into other specific forms without changing the technical spirit or essential features of the present disclosure. Therefore, the embodiments described above are exemplary in all respects and should not be construed as limiting.