KR100766954B1 - Fiber reinforced polymer bar having self-impregnated protrusion and method for producing the same - Google Patents

Abstract

A fiber reinforced polymer bar having a self-impregnated protrusion and a method for producing the same are provided to simplify the manufacturing process by integrating the steps for forming a core of an FRP(fiberglass reinforced plastics) reinforced bar with forming a projection. A fiber reinforced polymer bar having a self-impregnated protrusion and a method for producing the same comprise the steps of impregnating the first fibers(101) formed of a core(2) of an FRP(fiberglass reinforced plastics) reinforced bar into the resin, maintaining a whole section as a circular section to pass a nozzle(203) by applying the withdrawing force to the first fibers impregnated to the resin, winding or forming a projection to impregnate automatically the non-impregnated second and third fibers into the eluted resin, hardening the second fiber, the third fiber, and the core impregnated into the resin; and storing the second fiber, the third fiber, and the packet for core integrated through the hardening step.

Description

Fiber Reinforced Polymer Bar Having Self-Impregnated Protrusion and Method for Producing the Same}

Figure 1 is a schematic diagram showing a series of steps by the method of manufacturing a FRP rebar according to a preferred embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the winder in FIG. 1.

3 is a schematic enlarged perspective view of the FRP reinforcing bar passed through the nozzle of the winder in FIG.

4 is a partial cross-sectional view of the FRP rebar according to a preferred embodiment of the present invention.

5 is a photograph showing a cross section of the FRP rebar according to the prior art.

6 is a photograph showing a cross section of the FRP rebar according to the present invention.

7 is a graph showing the adhesion characteristics of the conventional FRP rebar and the FRP rebar according to the present invention.

8 is a perspective view of a winder according to a method for manufacturing FRP rebar according to another embodiment of the present invention.

9 is a perspective view of a FRP rebar according to the prior art.

<Description of the symbols for the main parts of the drawings>

1..FRP rebar 2 ... core

101 ... first fiber 102 ... second fiber

103 Third fiber 110 Bends

114 ... protrusion 116 ... resin wedge

203.Nozzle 204 ... Reel

208 Curing Machine 210 Drawing Machine

The present invention relates to a fiber-reinforced polymer reinforcing bar having a self-impregnated protrusion and a method of manufacturing the same, and more particularly, to fiber reinforced polymer (Fiber Reinforced Polyer / "FRP") reinforcing bar replacing the reinforcing steel used in reinforced concrete structures In the present specification, abbreviated as "FRP reinforcing bar"), the surface structure of the reinforcing bar to improve the adhesion strength to concrete, and to improve the productivity by simplifying the manufacturing process by self-impregnation, and to improve the productivity will be.

In general, reinforcing bars embedded in concrete cause severe corrosion due to various environmental factors. In particular, when exposed to corrosive environments such as chemicals for snow removal, seawater, etc., existing rebar made of steel cannot avoid severe corrosion even with epoxy coating. To be an element.

On the other hand, FRP has the advantages of high strength, no corrosion, and high strength / weight ratio, which can reduce the weight of concrete structures. It is recognized as a reinforcement.

Patent application 2002-0081219 discloses a conventional fiber-reinforced polymer bar, the shape of which is shown in a schematic perspective view in FIG. In the conventional fiber-reinforced polymer bar, the first fiber layer 11 in which the resin is already impregnated is wound on the outer circumferential surface of the FRP matrix 10 which has already been cured, and the second fiber layer in which the resin is impregnated thereon as well. (12) has a wound structure. In this conventional fiber reinforced polymer bar, since the first fiber layer 11 and the second fiber layer 12 impregnated with the resin are wound on the outer circumferential surface of the FRP matrix 10 while the FRP matrix 10 is already completely cured. The integrity of the first fiber layer 11 and the second fiber layer 12 and the FRP matrix 10 is low. Therefore, when the continuous load, the repeated fatigue load or the impact load is applied, or when used in high-strength concrete, the resin between the first fiber layer 11 and the second fiber layer 12 and the concrete is destroyed, so that the first fiber layer 11 And a phenomenon in which the second fiber layer 12 is peeled off, which lowers the adhesion performance. In addition, there is a disadvantage in that brittle behavior shows that the adhesive strength is sharply lowered after the maximum adhesive strength is expressed. In particular, in the case of the conventional fiber-reinforced polymer bar described above, the first fiber layer 11 and the second fiber layer 12 are wound in a state of being impregnated with the resin in the manufacturing process, and thus, about 90 to prevent curing of the resin. ~ 160 ?? Work must be carried out inside a chamber of temperature. Therefore, there is a disadvantage in that the manufacturing productivity is low because the manufacturing process is complicated and more special equipment for maintaining the temperature is required.

On the other hand, Patent Application No. 2002-0021789 discloses a "method of manufacturing a concrete reinforcement using a fiber-reinforced composite material", in the prior art described above coated particles such as silica on the outer peripheral surface of the FRP matrix composed of fibers and resins A method for producing a FRP reinforcing bar is disclosed in which a particle coating layer is formed to increase the frictional resistance of a surface.

However, in the conventional manufacturing method described above, a process for producing an FRP matrix composed of fibers and resins through a drawing process and a surface treatment such as particle coating are dualized, and thus, a complicated manufacturing process of several steps must be performed. Thereby, there is a problem in that manufacturing economy is lowered accordingly. Particularly in the case of FRP rebar made by such a manufacturing method, the particle coating is separated from the FRP matrix surface when continuous load, repeated fatigue load or impact load is applied, or when used in high strength concrete. As a result, adhesion performance is lowered, and as in the conventional fiber-reinforced polymer disclosed in Patent Application No. 2002-0081219, there is a disadvantage in that brittle behavior is shown in which the adhesion strength is sharply lowered after the maximum adhesion strength is expressed.

The present invention has been developed to solve the problems of the prior art as described above, and solves the disadvantages of the FRP reinforcing bar manufacturing process caused by the dual process for producing the FRP matrix and the surface treatment process, such as particle coating In addition, the purpose of the present invention is to solve the phenomenon of deterioration of adhesion performance between the FRP reinforcing bar and concrete and the manufacturing process complexity caused by winding the first fiber layer and the second fiber layer impregnated with resin after curing of the FRP matrix.

In short, the present invention is to improve the surface structure of the FRP reinforcement to improve the adhesion performance between the FRP reinforcement and concrete, and to provide a FRP reinforcement to simplify the manufacturing method by unifying the additional process for improving the existing adhesion performance.

In the present invention, in order to achieve the above object, the FRP rebar having an improved surface structure to improve the adhesion performance between the FRP reinforcement and concrete, and the additional process in the conventional manufacturing method that must go through complex steps to improve the adhesion performance By unifying, the manufacturing method of the FRP rebar which has improved the economics by simplifying the manufacturing method is provided.

Hereinafter, a method for manufacturing a FRP rebar according to an embodiment of the present invention with reference to the accompanying drawings.

1 is a schematic view showing a series of steps by the method of manufacturing the FRP rebar according to a preferred embodiment of the present invention.

Referring to FIG. 1, first, the core 2 of the FRP rebar 1 is formed by using a first fiber 101 serving as a core material and a reinforcing material of the FRP, as shown in FIG. 1. The bobbin 201 is used to supply a plurality of strands of the first fiber 101, and a resin impregnation step (S1) of impregnating the first fiber 101 thus supplied to the resin is performed. The resin impregnation step S1 of the first fiber 101 is performed by impregnating a plurality of strands of the first fiber 101 supplied from the bobbin 201 into the resin impregnation tank 202 containing the resin. The resin-impregnated first fibers 101 are bundled to form the core 2 of the FRP rebar 1.

Subsequently, the core material 2 made of the first fiber 101 is subjected to a circular cross-section forming step S2 of which the cross section forms a circular shape while passing through the nozzle 203. That is, as shown in the drawing, in the present invention, the core material 2 is formed by using a nozzle 203 having a diameter smaller than the diameter of the core material 2 made of the bundle of the first fibers 101 impregnated with the resin. By passing through the nozzle 203, the core bundle 2 in the core member 2 has a circular cross section in a state of tension and maintains straightness. As described above, in the present invention, the core material 2 is pulled by the drawer 210 provided in front of the nozzle 203 and pressed into the nozzle 203. The core material (2) is drawn by the drawer 210. Since 2) is strongly pulled, each of the first fibers 101 in the bundle of the first fibers 101 constituting the core material 2 maintains straightness to increase elastic modulus and tensile strength, respectively, by the nozzle 203. The first fibers 101 are compressed to have an advantageous effect that the voids therein are removed. In addition, since the core material 2 is pulled by the drawer 210 and passes through the nozzle 203 in this way, unnecessary resin that penetrates the core material 2 during the passage of the nozzle 203 may cause the nozzle 203 to be removed. It does not pass and is removed behind the nozzle 203.

The core material 2 drawn out in a circular shape through the nozzle 203 is subsequently wound with unimpregnated second fiber 102 and third fiber 103 which are not impregnated in resin as follows to form a projection. And it is subjected to the projection forming step (S3). FIG. 2 is an enlarged view of the winder 204 shown in FIG. 1.

Referring to FIG. 2, the nozzle 203 is provided at the center of the winding machine 204, and the first supply winding part for supplying and winding the second fiber 102 at a short distance from the nozzle 203 ( 205 is provided, and a plurality of second supply winding portions 206 for supplying and winding the third fibers 103 are provided on the outside thereof. Although one first supply winding unit 205 and eight second supply winding units 206 are shown in the drawing, the present invention is not limited thereto, and an appropriate number of first and second supply winding units 205 and 206 may be provided. have. Preferably, one or two first supply winding units 205 may be installed on the winding machine 204, and 16 to 32 second supply winding units 206 may be provided. The second fiber 102 is supplied and wound through the first supply winding unit 205, and the second fiber 102 has a coarse diameter as compared to the third fiber 103. It is wound around the outer circumferential surface to form a protrusion like a deformed part of a reinforcing bar.

The third fiber 103 is supplied and wound through the second supply winding part 206, and the third fiber 103 has a smaller diameter than the second fiber 102, and the core material 2 ) And the outer circumferential surface of the second fiber 102 are tightly wrapped like a mesh to form the protrusion 114. Next, the process of forming the protrusions 114 by winding the second and third fibers 102 and 103 will be described in detail with reference to FIG. 3.

3 is an enlarged view illustrating a state in which the second and third fibers 102 and 103 are wound around the core 2 passing through the nozzle 203 and the winding machine 204.

Referring to FIG. 3, the second fiber 102 is pulled tightly by the first supply winding part 205 on the surface of the core 2 made of the first fiber 101, that is, in a state where tension is applied. Is wound into. Accordingly, the bent portion 110 is formed on the outer circumferential surface of the core material 2 by the second fiber 102 wound by tension, and the second fiber 102 itself is Protruding portion protruding from the surface of the core material (2). The second fiber 102 was in an unimpregnated state not impregnated with the resin. As described above, since the second fiber 102 is pulled by the tension and wound while forming the bent portion 102 in the core material 2, Although not shown in the figure, the resin filled in the core 2 is eluted to the outside of the core 2 and the second fiber 102 is impregnated with the naturally eluted resin. Therefore, the additional work of impregnating the second fiber 102 in the resin separately using an impregnation tank or the like is not necessary at all. In particular, since the second fiber 102 is impregnated by the resin inside the core 2, not only the integrity of the core 2 and the second fiber 102 can be improved, but also the bent portion formed in the core 2 itself. By 110, the FRP reinforcing bar 1 of the present invention has the advantage of exhibiting additional adhesion in addition to the adhesion of the core material 2 and the second fiber (102).

After the second fiber 102 is wound along the outer circumferential surface of the core material 2, a plurality of third fibers 103 are wound on the surface of the core material 2 and the second fiber 102 to form a surface protective layer. The third fiber is to form a protrusion. Similarly to the second fiber 102, the third fiber 103 also tightly wraps the surface of the core material 2 and the second fiber 102 like a net in a state where tension is applied by the second supply winding part 206. do. The third fiber 103 was also in an unimpregnated state not impregnated with a resin. As described above, after the second fiber 102 is wound up, the third fiber 103 immediately follows the outer peripheral surface of the core material 2. Since the third fiber 103 is wound up, it is naturally impregnated with the resin eluted from the inside of the core 2 to the outside, similarly to the second fiber 102. The term 'self-impregnation' in the name of the present invention, as described above, while the unimpregnated second and third fibers 102 and 103 are wound on the core 2 by tension, from the inside of the core 2 to the outside. It originates in the process of being naturally impregnated with the eluting resin.

Through the above-described process, the protrusion 114 is formed on the outer circumferential surface of the core material 2 by the protrusion of the second fiber 102 and the third fiber 103 surrounding the surface thereof. This protrusion 114 serves to reinforce the adhesion of the FRP reinforcing bar 1 of the present invention together with the bent portion 110 formed on the core material 2 by the second fiber (102).

On the other hand, although not shown in the drawings, the first and second supply windings (205, 206) for winding the second and third fibers (102, 103) on the core 2, the direction in which the core 2 Each may be provided along a separate winder. That is, the first supply winding unit 205 is wound first along the advancing direction of the core material 2 to surround the second fiber 102 on the outer circumferential surface of the core material 2, Subsequently, a second supply winding part 206 for winding the third fiber 103 is disposed to surround the third fiber 103 on the outer circumferential surfaces of the core material 2 and the second fiber 102. Also, the first supply winding unit 205 and the second supply winding unit 206 are installed in one winding machine, and the winding time is staggered so that the second fiber 102 is placed on the core material 2 more than the third fiber 103. It may also be configured to be wound first.

Referring back to FIG. 1, the second and third fibers 102 and 103 are wound on the surface of the core 2, and then subjected to a curing step S4. In the curing step (S4), the resin eluted from the inside of the core material 2 to the outside by the hardener 208 is hardened to complete the FRP reinforcing bar, and the second and third fibers 102 and 103 impregnated in the resin. ) And the core 2 are improved in unity by the cured resin.

The hardened FRP rebar 1 is subsequently subjected to the drawing and storage step (S5). In the drawing and storage step (S5), as described above, by pulling the FRP reinforcement (1) by the drawer 210, while the FRP reinforcement (1) having the appropriate tension in the circular cross-section maintenance and winding step (S2) Pass through the nozzle 203. The FRP rebar 1 passing through the drawer 210 is wound around the storage bobbin 212 or stored in a suitable length by a cutter (not shown).

4 is a partial cross-sectional view of the FRP rebar 1 of the present invention produced by the above-described manufacturing method.

Referring to FIG. 4, as described above, the bent part 110 is formed on the surface of the core 2 by the second fiber 102 that is pulled and wound by tension, and the third fiber 103 is the second fiber. The protrusion 114 is formed while surrounding the outer circumferential surface of the 102. As a result, the core material 2, the second and third fibers 102 and 103 have a structure impregnated with the resin 4. As shown in FIG. 4, the space between the bent part 110 of the core material 2 and the third fiber 103 is filled by the resin 4 eluted in the core material 2 to have a wedge shape. The part 116 is formed. In the partial enlarged view of FIG. 4, the resin wedge 116 is indicated by a dotted line for convenience of description. The resin wedge portion 116 improves the integrity of the core material 2 and the second and third fibers 102 and 103, so that the second and third materials may be applied even when a continuous load, a repeated fatigue load or an impact load is applied. The three fibers 102 and 103 are not peeled off from the core 2.

Figure 5 shows a photograph taken with a scanning electron microscope (Scanning Electron Microscope / "SEM") to enlarge the cross-section of the prepared reinforcing bar 50 times without applying tension to the second and third fibers when manufacturing the FRP reinforcement, Figure 6 is a scanning electron microscope (Scanning Electron Microscope / "SEM") by expanding the cross-section of the FRP reinforcement (1) produced by applying the tension to the second and third fibers (102, 103) in accordance with the present invention 200 times This picture was taken.

As shown in FIG. 5, when the outer circumferential surface of the FRP core is wrapped around the second and third fibers without introducing tension, a plurality of voids are present in the cross section of the FRP core. These voids are caused by hardening of the FRP core in a state where the FRP core is not sufficiently compressed, thereby significantly reducing the strength of the FRP rebar.

On the other hand, as shown in Figure 6, by applying the tension to the second and third fibers 102, 103 by the present invention to surround the outer peripheral surface of the core material 2, the first fiber forming the core material (2) It can be seen that the 101 are compressed so that voids rarely occur therein. Thereby, it can be seen that the FRP reinforcing bar 1 of the present invention is significantly improved in strength as compared with the prior art.

Figure 7 is a graph showing the results measured by measuring the adhesion characteristics of the FRP reinforcement bar (1) and the reinforcement bars according to the prior art of the present invention concrete. In FIG. 7, the FRP reinforcing bar of the present invention is indicated by a solid line, and in the case of FRP reinforcing bar simply coated with silica sand on the outer circumferential surface of the hardened FRP core, the resin (R) or fiber is simply added to the outer circumferential surface of the hardened FRP core. The FRP rebars manufactured in the form of windings are indicated by inverted triangles (B bar). In the graph of FIG. 7, the x axis represents displacement / maximum displacement, and the y axis represents load / maximum load.

As shown in the graph of Figure 7, in the case of the FRP rebar according to the prior art brittle fracture after reaching the maximum bond strength, in the case of the FRP rebar (1) of the present invention reached the maximum bond strength Afterwards, the bond strength similar to the maximum bond strength is maintained for a predetermined displacement, thereby improving the safety of the concrete structure.

8 is a view showing a winder 204 ′ used in the winding step (S3) in the method of manufacturing a FRP rebar according to another embodiment of the present invention. This embodiment differs only from the method of winding the second and third fibers 102 and 103 on the outer circumferential surface of the core 2 as compared with the above-described embodiment. Hereinafter, the difference will be described.

Referring to FIG. 8, in the present embodiment, the first supply winding unit 205 for winding the second fiber 102 and the second supply winding unit 206 for winding the third fiber 103 are the winding machines 204 ′. It is provided at the same distance from the center of). Accordingly, the second fiber 102 is first wound on the surface of the core 2 that has passed through the nozzle 203, and the third fiber 103 is not wound on the outer circumferential surface thereof, but along the outer circumferential surface of the core 2. The second and third fibers 102 and 103 are wound alternately. Meanwhile, in the present embodiment, the second and third fibers 102 and 103 are wound while being pulled by the tension, so that the second and third fibers 102 and 103 are made of resin eluted from the inside of the core material 2. ) Is impregnated.

As described above, the FRP rebar manufacturing method according to the present invention can be simplified by significantly reducing the manufacturing process by uniting the process of forming the core material and the process of forming the projections of the FRP rebar reinforcement.

In addition, according to the present invention, by applying tension to the second and third fibers wound on the FRP core material, the voids in the FRP core material are removed to improve the strength of the FRP reinforcing bar, and the resin filled inside the FRP core material to the outside. It can be eluted to impregnate the second and third fibers. In particular, when forming the FRP core material, since the first fibers enter the nozzle while being strongly pulled, the straightness of the first fiber is maintained, thereby densifying the inside of the FRP core material and increasing the strength.

Further, according to the present invention, the second and third fibers are wound before curing the FRP core material impregnated with the resin, and then the curing step is performed to significantly improve the integrity of the FRP core material and the second and third fibers. Can be.

In addition, according to the present invention, in addition to the adhesive force by the resin, the protrusion formed by the second and third fibers, the fine irregularities and the bent portion of the core material formed by the third fiber that is the surface protective layer and the second and third fibers Significant adhesion strength is exerted by the resin wedge formed by filling with resin.

In the above described the configuration and features of the present invention based on the embodiment according to the present invention, the present invention is not limited to this, it is possible to be freely modified according to the technical idea of the present invention.

Claims (9)

As a method of manufacturing FRP rebar, Resin impregnation step of impregnating a plurality of first fibers to form a core material of the FRP reinforcement to the resin, A circular cross section maintaining step of applying a pulling force to the plurality of first fibers impregnated in the resin to pass through the nozzle so that the entire cross section maintains a circular shape; The unimpregnated second fiber, not impregnated with the resin, is wound by applying tension along the outer circumferential surface of the core material consisting of the first fibers, and by applying the tension along the outer circumferential surface of the core material and the second fiber. Take and form protrusions along the outer circumferential surface of the core material, and resin filled in the core material is eluted to the outside by the tension of the second and third fibers wound on the core material to the outside to impregnate the second and third fibers. Winding and protrusion forming steps to automatically impregnate the eluted resin, A curing step of curing the second fiber, the third fiber and the core material impregnated with resin; The method of manufacturing a FPR reinforcing bar with self-impregnated protrusions, comprising the step of drawing and storing the bundle of the second fiber, the third fiber and the core material integrated through the curing step. The method of claim 1, In the winding and protrusion forming step, The method of manufacturing a FRP reinforcing bar having a self-impregnated protrusion characterized in that the bent portion is formed along the outer peripheral surface of the core by the tension of the second fiber wound on the core. The method of claim 2, The space between the bent portion of the core material and the third fiber is filled with a resin eluted from the core material, to form a resin wedge portion having a wedge shape in cross section, characterized in that the manufacturing method of the FRP reinforcement with self-impregnated projections. The method of claim 3, The second fiber has a larger diameter than the third fiber, characterized in that the manufacturing method of the FRP reinforcing bar with self-impregnated projections. The method of claim 4, wherein And a plurality of third fibers wound along the outer circumferential surface of the core material and the second fiber are wound in a mesh shape to cover the surface of the core material and the second fiber. An FRP rebar having self-impregnated protrusions produced by the manufacturing method according to any one of claims 1 to 5. As a method of manufacturing FRP rebar, Resin impregnation step of impregnating a plurality of first fibers to form a core material of the FRP reinforcement to the resin, A circular cross section maintaining step of applying a pulling force to the plurality of first fibers impregnated in the resin to pass through the nozzle so that the entire cross section maintains a circular shape;  Tension is applied along the outer circumferential surface of the core material to alternately wind the second fiber and a third fiber having a smaller diameter than the second fiber to form protrusions along the outer circumferential surface of the core material by the second fiber. A winding and protrusion forming step in which the resin filled in the core material is eluted to the outside by the tension of the second and third fibers, and the second and third fibers are impregnated in the eluted resin; A curing step of curing the second fiber, the third fiber and the core material impregnated with resin; Method for producing a FPR reinforcing bar with self-impregnated protrusions, characterized in that it comprises the step of drawing and storing the bundle of the second fiber, the third fiber and the core material integrated through the curing step The method of claim 7, wherein In the winding and protrusion forming step, The method of manufacturing a FRP reinforcing bar having a self-impregnated protrusion characterized in that the bent portion is formed along the outer peripheral surface of the core by the tension of the second fiber wound on the core. An FRP rebar having self-impregnated protrusions produced by the manufacturing method according to claim 7.

Images