JPWO2014192073A1 - Carbon fiber rebar, manufacturing method thereof, continuous manufacturing apparatus and concrete structure - Google Patents

Abstract

Summary The carbon fiber (1c) is coated with fine particles mainly composed of silicon dioxide, and the surface of the carbon fiber coated with the fine particles is coated with a cement paste to solidify the entire carbon fiber reinforcement ( By adopting 1), when this carbon fiber rebar is embedded in a concrete structure instead of a rebar, a high power transmission efficiency and a large reinforcing effect can be obtained. Figure 1

Description

  The present invention relates to a carbon fiber reinforcement used for reinforcing the strength of reinforced concrete structures (including RC structures and SRC structures), a manufacturing method thereof, a continuous manufacturing apparatus, and a concrete structure.

  Conventionally, a reinforced concrete structure is strong against compression but weak against tension, and thus is reinforced by inserting a reinforcing bar into a portion where a tensile load is applied. The compatibility between concrete and rebar is good, the coefficients of thermal expansion are almost equal, and the rebar does not rust because the concrete is alkaline.

  However, it is known that when concrete is cracked or the like and the concrete is neutralized, the steel bars whose surface is exposed are corroded and deteriorated. Therefore, in recent years, carbon fibers that have a tensile strength as high as 10 times that of iron, a specific gravity as low as 1/4 of iron, and are chemically stable have come to be used. For example, a reinforcing carbon fiber described in JP-A-2000-129861 (Patent Document 1) is known.

JP 2000-129861 A

  In the conventional reinforcement with carbon fiber, it is a problem that the adhesion with concrete is inferior, and although it has been attempted to bring the carbon fiber into direct contact with concrete, the reinforcement effect cannot be obtained. Therefore, as described in Patent Document 1 described above, carbon fiber and synthetic resin using a non-hydrophilic synthetic resin adhesive (for example, epoxy resin) as a carbon fiber converging agent (sizing agent). A method of adhering carbon fibers using a resin-based material on the concrete itself is being performed. However, the hardness of the epoxy resin is inferior to that of concrete (Young's modulus is about 1/6 of the Young's modulus of concrete).

  The Young's modulus of carbon fiber is 5-6 times the Young's modulus of concrete and is hard, but when an external force is applied to the concrete, in the process that the force is transmitted to concrete → synthetic resin adhesive → carbon fiber, Since the soft synthetic resin adhesive is sandwiched between them, there is a problem that many strains are generated and force is not efficiently transmitted, and the reinforcing effect is not so high and is not practical. Moreover, since the synthetic resin adhesive is inferior in hydrophilicity, there is also a problem that the adhesive force with concrete is small. The carbon fiber rebar, the manufacturing method thereof, the continuous manufacturing apparatus, and the concrete structure according to the present invention have been proposed in order to solve such problems.

  In order to solve the above problems and achieve the object, the carbon fiber streak according to the present invention has a carbon fiber surface coated with fine particles mainly composed of silicon dioxide, and the surface of the carbon fiber coated with the fine particles. Further, the entire structure was solidified by being coated with cement paste.

The fine particles are preferably natural pozzolana, wollastonite, blast furnace slag, silica fume or fly ash fine particles.
Further, the cement paste is preferably formed by mixing water and a water reducing agent into cement.
The fiber muscle is preferably a rod-shaped body having a desired length.

  In the method for producing carbon fiber reinforcement according to the present invention, a tow bundle of carbon fibers is twisted into one carbon fiber bundle, and the carbon fiber bundle is prepared by dissolving fine particles mainly composed of silicon dioxide in water. The carbon fiber bundle taken out from the coating solution is removed from the carbon fiber bundle by moisture removal means, and the carbon fiber bundle is immersed in a cement paste solution, and then the carbon fiber bundle. Each step of curing and solidifying to form a rod-like body is included in that order.

  In order to increase the impregnation efficiency, the carbon fiber bundle is used in the step of immersing in the coating solution, in the step of immersing in the solution of cement paste, or in the step after these impregnation steps. Thus, it is preferable to apply vibration to the carbon fiber bundle or evacuate it with a vacuum device.

  Furthermore, the carbon fiber reinforcing method according to the present invention includes a vacuum pump, a vacuum container connected to the vacuum pump, and a carbon fiber bundle that is rotatably provided in the vacuum container and wound up. Forming a continuous production device for carbon fiber reinforcement comprising a drum to be fed, a pipe connected to the vacuum container and suspended, and a cement container for storing cement paste so that the lower end of the pipe is buried in the liquid And coating the carbon fiber bundle by immersing the carbon fiber bundle in a coating solution in which fine particles mainly composed of silicon dioxide are dissolved in water, and then winding the carbon fiber bundle around the drum to place the drum in the vacuum container. The one end of the carbon fiber bundle is pulled out from the drum and inserted into a pipe, and is inserted into the cement container through an opening at the lower end of the pipe and taken out to the outside. Dumps is driven by aged pull the carbon fiber bundle while vacuuming the external solidified to produce a carbon fiber muscle of the rod-like body continuous, it is intended to include the steps.

  A vibration device is attached to a part of the pipe, and it is preferable that air or excess bubbles entrained in the carbon fiber bundle is extracted by the vibration device.

  A continuous production apparatus for carbon fiber reinforcement according to the present invention includes a vacuum pump, a vacuum container to which the vacuum pump is connected, and a drum that feeds a wound carbon fiber bundle that is rotatably provided in the vacuum container. And a pipe connected to the vacuum container and suspended, and a cement container for storing the cement paste so that the lower end of the pipe is buried in the liquid.

  It is preferable that a vibration exciter is attached to a part of the pipe of the continuous production apparatus in order to extract air and excess bubbles entrained in the carbon fiber bundle.

  In the concrete structure according to the present invention, the above-described carbon fiber rebars are laid and embedded in concrete in an appropriate arrangement.

  According to the carbon fiber streak of the present invention, its production method and continuous production apparatus, hydrophilicity is achieved by coating the surface of carbon fiber with fine particles mainly composed of silicon dioxide without using a synthetic resin adhesive. Therefore, the cement paste strongly adheres to the carbon fiber, and by embedding it in the concrete structure instead of the reinforcing bar, the adhesion between the concrete and the carbon fiber reinforcement is improved, and the tensile strength is enhanced.

  Since a conventional synthetic resin adhesive having a low Young's modulus is not used, the force applied to the concrete structure directly acts on the carbon fiber reinforcement. Therefore, the big reinforcement effect by carbon fiber reinforcement is acquired.

Moreover, since there is no possibility of being corroded by carbon fiber reinforcement, the service life of the concrete structure can be greatly extended.
Furthermore, since the reinforcing bars are made of carbon fiber, there is no deterioration of the material due to chlorine ions, it is possible to use sea sand as a concrete material, and it is easy to obtain as an aggregate necessary for concrete at a low cost. There is an effect.

By the carbon fiber reinforcement manufacturing method, a rod-like carbon fiber reinforcement covered with cement paste is formed, and when this is embedded in concrete, it becomes a reinforcing reinforcement integrated with the concrete structure.
The vibration device efficiently removes air and bubbles existing between the surface of the carbon fiber streaks and the bundle of carbon fiber tows, so that the effect of fine particle coating and cement paste impregnation is improved.

  In addition, the carbon fiber reinforcement according to the present invention can be efficiently and continuously produced by the continuous production method and continuous production apparatus of the carbon fiber reinforcement.

It is process drawing which shows the process (A)-(C) which forms the carbon fiber bundle (henceforth the same) which is a bundle of tow | carbon tow of the carbon fiber before the coating process for manufacturing the carbon fiber reinforcement which concerns on this invention. . It is process drawing which shows the process (A)-(C) which coats the carbon fiber bundle before a process for manufacturing the same carbon fiber streaks with fine particles. It is process drawing which shows the process (A)-(C) which impregnates the carbon fiber bundle which coated the fine particle for cement paste for manufacturing the carbon fiber reinforcement. It is a side view which shows the apparatus which manufactures the same carbon fiber reinforcement continuously.

  As shown in FIGS. 1 to 3, the carbon fiber reinforcement 1 according to the present invention is coated with fine particles mainly composed of silicon dioxide and then impregnated with cement paste in order to maintain the hydrophilicity of the carbon fiber. It is made to coat.

As shown in FIG. 1, the carbon fiber reinforcement 1 according to the present invention first forms a carbon fiber bundle 1a.
For this purpose, as shown in steps (A) and (B) of FIG. 1, a plurality of carbon fibers (diameter: 5 to 15 μm) 1c (12000 as an example) are bundled to form one tow 1b. .

  Further, as shown in steps (B) and (C) of FIG. 1, a plurality of tows 1b (21 as an example) are bundled to form a tow bundle 1d. Are twisted and wound on a drum 2a to form a carbon fiber bundle 1a.

  Then, as shown in step (A) of FIG. 2, the surface of the carbon fiber of the carbon fiber bundle 1a is coated with fine particles having a diameter of less than or equal to a micrometer and having silicon dioxide as a main component. The fine particles are fine particles such as natural pozzolana, wollastonite, blast furnace slag, silica fume or fly ash. The natural pozzolan is volcanic ash, diatomaceous earth, silicate clay, etc., and produces a pozzolanic reaction like fly ash. The coating solution 3 in which the fine particles are dissolved and dispersed in water is stored in the coating container 4, and the carbon fiber bundle 1a is immersed therein.

  As an example of the coating solution 3, 1 g of silica fume is dissolved in 1000 g of water.

  During the coating, air is entrained on the surface or inside of the carbon fiber or between the carbon fibers, so as shown in step (B) of FIG. 2, the vacuum suction connected to a vacuum device such as a vacuum pump. Preferably, the coating container 4 is placed in a vacuum container 5 for coating.

  In the coating shown in step (A) of FIG. 2, the carbon fiber bundle 1 a is applied to the carbon fiber bundle 1 a via the coating container 4 by, for example, several Hz to 25 KHz by a vibration device that is generally used in the construction field. The air may be removed by applying a certain degree of vibration. In this way, air is vented, but if it is difficult to perform air venting simultaneously with the coating operation, air venting may be performed after the coating process.

  Next, since the carbon fiber bundle 1a contains a large amount of water, excess water is removed from the carbon fiber bundle 1a as shown in step (C) of FIG. In order to remove the moisture, for example, the carbon fiber bundle 1a is squeezed, or the carbon fiber bundle 1a is wound with a dry material to absorb moisture, or centrifugal force is applied to the carbon fiber bundle 1a to remove moisture. Flying is an example of moisture removal means. In this way, the coating process is performed.

  Next, the surface of the carbon fiber in the carbon fiber bundle 1a coated with the fine particles is coated with a cement paste to solidify the whole.

  As shown in step (A) of FIG. 3, the cement paste 6 is stored in the cement container 7, and the carbon fiber bundle 1a is stored in the cement container 7 in a state of being straightened in the atmosphere. It is immersed in the cement paste 6 and impregnated.

  The cement paste 6 is formed by mixing water and a water reducing agent into cement. In this blending example, for example, Portland cement is 100 parts by weight, silica fume is 5 to 20 parts by weight, water is 16 to 40 parts by weight, and water reducing agents (polycarboxylic acid-based, naphthalene-based, aminosulfonic acid-based commercial products, etc. Of 0.5 to 5 parts by weight. Silica fume has the effect of increasing the viscosity and adhesive strength, but it will not solidify if its amount is increased too much. Therefore, it is preferable to cause a pozzolanic reaction by appropriately adding calcium hydroxide or aluminum hydroxide.

  When the carbon fiber bundle 1a is impregnated with the cement paste 6, it is preferable to perform air bleeding. For this purpose, for example, applying vibration to the carbon fiber bundle 1a via the cement container 7 with a vibration device, shaking the carbon fiber bundle 1a up and down, left and right, as shown in step (B) of FIG. Air is vented by placing in the vacuum vessel 5 and impregnating in vacuum (vacuum defoaming). If it is difficult to carry out in vacuum, the carbon fiber bundle 1a impregnated with the cement paste 6 can be evacuated in a later step.

  Then, the carbon fiber bundle 1a is put in a mold or in a hose-like frame, and the carbon fiber 1a is hung or held horizontally and steam-cured to solidify the carbon fiber bundle 1a. Then, the whole is cut into a required length to form a rod-like carbon fiber streak 1 as shown in step (C) of FIG.

  As described above, the carbon fiber tow bundle is twisted into one carbon fiber bundle 1a, and the carbon fiber bundle 1a is made of the coating solution 3 in which fine particles mainly composed of silicon dioxide are dissolved in water. The carbon fiber bundle 1a dipped in the coating solution 3 is removed from the carbon fiber bundle 1a by water removal means, and the carbon fiber bundle 1a is immersed in a cement paste solution. The bundle 1a is put in a mold or the like and cured and solidified to form a rod-shaped body.

  In addition, when the carbon fiber bundle 1a is immersed in a coating solution, or in a cement paste solution, or in a step after these impregnation steps, a vibration device is used to increase the impregnation efficiency. It is preferable to apply vibration to the carbon fiber bundle 1a or evacuate it with a vacuum device. Thus, air is vented and the impregnation effect is enhanced.

  The structure of the continuous production apparatus 8 of the carbon fiber reinforcement which concerns on this invention is demonstrated. As shown in FIG. 4, the continuous production apparatus 8 for carbon fiber rebar is provided with a vacuum pump 10, a vacuum container 9 to which the vacuum pump 10 is connected, and a rotatable inside the vacuum container 9. A drum for feeding the wound carbon fiber bundle 1a, a pipe 11 connected to the vacuum container 9 and suspended, and a cement container 7 for storing cement paste so that the lower end of the pipe 11 is buried in the liquid. And consist of

  A vibration device 12 is attached to a part of the pipe 11 so as to extract air and excess bubbles entrained in the carbon fiber bundle 1a.

  As shown in FIG. 4, the carbon fiber streak continuous production apparatus 8 is formed by forming the continuous production apparatus 8 and dissolving the carbon fiber bundle 1a with fine particles mainly composed of silicon dioxide. After dipping in the solution and coating, the carbon fiber bundle 1a is wound around the drum 2a and placed in the vacuum container 9, and one end of the carbon fiber bundle 1a is inserted from the pipe 11 into the cement container 7. Take it out.

  The continuous production apparatus 8 in FIG. 4 continuously produces the carbon fiber bundle 1a by pulling the carbon fiber bundle 1a to the outside while evacuating (vacuum degassing) with the vacuum hose 10a by driving the vacuum pump 10. It is.

  When the vacuum container 9 is evacuated by the vacuum pump 10, the cement paste 6 in the cement container 7 is pulled up in the pipe 11 by about 5 m by atmospheric pressure. The cement paste 6 is linearly inserted into the carbon fiber bundle 1a from top to bottom, and the cement paste 6 is impregnated between the outer peripheral surface of the carbon fiber bundle 1a and the fibers.

  Further, when the carbon fiber bundle 1a is impregnated with the cement paste 6 by the vibration device 12, air is vented to remove air and bubbles so that the cement paste 6 is efficiently impregnated.

  The bundle of carbon fiber strands 1a that has been inserted through the cement container 7 and taken out to the outside is then put into a mold or the like, steam-cured, solidified, cut into a required length, and turned into a carbon fiber strand 1a.

  The carbon fiber rebar 1 formed as described above is placed in a formwork and placed in concrete to become a reinforcing bar for a concrete structure instead of a rebar, and is strong against tension and rich in durability. It is a concrete structure.

  The carbon fiber reinforcement, the manufacturing method thereof, the continuous production apparatus, and the concrete structure according to the present invention can be widely used not only for a concrete frame but also for various structures as a reinforcing bar in place of a reinforcing bar of a concrete structure.

1 carbon fiber reinforcement, 1a carbon fiber bundle,
1b tow, 1c carbon fiber,
1d tow bundle,
2 twisting device, 2a drum,
3 coating solution,
4 coating containers,
5 vacuum container,
6 cement paste,
7 Cement container,
8 continuous production equipment,
9 Vacuum container,
10 vacuum pump, 10a vacuum hose,
11 pipes,
12 Exciter.

Claims (11)

The surface of the carbon fiber is coated with fine particles mainly composed of silicon dioxide,
The surface of the carbon fiber coated with the fine particles is coated with cement paste and solidified as a whole.
Carbon fiber reinforcement characterized by The fine particles are natural pozzolans, wollastonite, blast furnace slag, silica fume or fly ash fine particles,
The carbon fiber reinforcement according to claim 1, wherein: Cement paste is a mixture of water and water reducing agent mixed with cement.
The carbon fiber reinforcement according to claim 1, wherein: The carbon fiber reinforcement is a rod-shaped body having a desired length,
The carbon fiber reinforcement according to claim 1, wherein: Twist a bundle of carbon fiber tows into one carbon fiber bundle,
The carbon fiber bundle is immersed in a coating solution obtained by dissolving fine particles mainly composed of silicon dioxide in water,
The carbon fiber bundle taken out from the coating solution is removed from the carbon fiber bundle by moisture removing means,
Immerse the carbon fiber bundle in a cement paste solution,
Thereafter, the carbon fiber bundle is cured and solidified to form a rod-shaped body,
Each process of these is included in the order of the said description, The manufacturing method of the carbon fiber reinforcement characterized by the above-mentioned. In order to increase the impregnation efficiency in the step of immersing the carbon fiber bundle in the coating solution, in the step of immersing in the solution of the cement paste, or in the step after these impregnation steps, a vibration device is used. Applying vibration to the carbon fiber bundle, or evacuating with a vacuum device,
The method for producing carbon fiber reinforcement according to claim 5. A vacuum pump,
A vacuum container to which the vacuum pump is connected;
A drum that is rotatably provided in the vacuum vessel and feeds the wound carbon fiber bundle;
A pipe vertically connected to the vacuum vessel;
Forming a continuous production device for carbon fiber reinforcement, comprising a cement container for storing cement paste so that the lower end of the pipe is buried in the liquid,
After coating the carbon fiber bundle by immersing it in a coating solution in which fine particles mainly composed of silicon dioxide are dissolved in water,
The carbon fiber bundle is wound around the drum and the drum is installed in the vacuum container.
One end of the carbon fiber bundle is drawn out from the drum and inserted into a pipe, and is inserted into the cement container from the opening at the lower end of the pipe and taken out to the outside.
Driving the vacuum pump and pulling the carbon fiber bundle to the outside while evacuating it, curing and solidifying, continuously producing rod-shaped carbon fiber streaks,
A method for producing carbon fiber reinforcement characterized by the above. A vibration device is attached to a part of the pipe, and the vibration device removes air and excess bubbles entrained in the carbon fiber bundle,
The manufacturing method of the carbon fiber reinforcement of Claim 7 characterized by these. A vacuum pump,
A vacuum container to which the vacuum pump is connected;
A drum that is rotatably provided in the vacuum container and feeds the wound carbon fiber bundle;
A pipe vertically connected to the vacuum vessel;
A cement container for storing cement paste so that the lower end of the pipe is buried in the liquid;
An apparatus for continuous production of carbon fiber reinforcement characterized by the above. In order to extract air and excess bubbles entrained in the carbon fiber bundle, a vibration device is attached to a part of the pipe,
The continuous production apparatus for carbon fiber reinforcement according to claim 9. The carbon fiber reinforcement according to claims 1 to 4 is laid and embedded in concrete;
A concrete structure characterized by

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