JP2002047799A - Constructing method of concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constructing method of concrete structure which can control the orientation of fibers of fiber reinforced concrete. SOLUTION: According to the constructing method of concrete structure which is carried out by pouring the fiber reinforced concrete from a discharge portion into a form, current plates attached to the discharge portion are arranged at intervals in a direction almost orthogonal to a discharging direction of the concrete such that the mutually facing current plates are almost in parallel with each other. Then, the fiber reinforced concrete is poured while the discharge portion is moved in a predetermined direction. Herein, the discharge portion to which the current plates are attached may be tapered toward the discharging direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for constructing a concrete structure using fiber reinforced concrete as a material.

[0002]

2. Description of the Related Art When constructing a concrete structure using fiber-reinforced concrete as a material, a fiber-reinforced concrete is poured into a formwork to construct a concrete structure, as in the case of casting concrete. The fibers in the concrete structure thus constructed are oriented in various directions, and it is preferable for a structure subjected to loads from various directions because the resistance of the concrete structure in all directions is reinforced by the fibers. Was something.

[0003]

On the other hand, when the direction of the load acting on the concrete structure or the direction of deformation is clear, the fibers are aligned in a predetermined direction to increase the resistance in that direction. It is preferable to maximize the fiber reinforcement effect. However, if fiber reinforced concrete is cast in a conventional manner, the fibers in the concrete structure will face various directions. And it was difficult to control the direction of the fiber in an arbitrary direction.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method for constructing a concrete structure capable of controlling the direction of fibers of fiber-reinforced concrete. .

[0005]

In order to achieve the above object, a method for constructing a concrete structure according to the present invention is directed to a method for constructing a concrete structure in which fiber-reinforced concrete is poured from a discharge portion into a formwork. In the method,
Attach the rectifier plate attached to the discharge part at intervals in the direction substantially perpendicular to the concrete discharge direction so that the facing rectifier plate is substantially parallel, and mold the fiber reinforced concrete while moving the discharge part in a predetermined direction. It is a method of pouring into the frame. Here, the discharge section to which the rectifying plate is attached may be shaped so as to be tapered in the discharge direction.

[0006]

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

<A> Discharge Portion The discharge portion 2 is a discharge port attached to the end of the hose 22 or the hopper when the fiber reinforced concrete is poured into the mold. The discharge unit 2 is attached to, for example, the tip of a hose 22 via a rotatable rotating unit 23. The fiber reinforced concrete 1 that has passed through the hose 22 flows out of the discharge part 2 (FIG. 1).
reference). Further, the discharge unit 2 may have a shape that tapers in the discharge direction. FIG. 2 shows a perspective view of the tapered discharge section. The following rectifying plate 21 is attached near the tip of the discharge unit 2.

<B> Rectifying Plate The rectifying plate 21 is a plate member for adjusting the direction of the fibers in the fiber-reinforced concrete passing between the rectifying plates or between the rectifying plate and the side wall of the discharge portion. A plurality of rectifying plates 21 are installed near the tip of the discharge unit 2. The plurality of flow regulating plates 21 are arranged at intervals in a direction substantially orthogonal to a direction in which the fiber reinforced concrete flows out from the discharge portion (hereinafter, referred to as a discharge direction). Here, the adjacent current plates 21 face each other and are arranged substantially in parallel.

<C> Fiber-reinforced concrete Fiber-reinforced concrete 1 is concrete in which the properties such as tensile strength, bending strength, and toughness are improved by mixing fibers of metal or synthetic resin into concrete. The fiber reinforced concrete 1 used in the present invention preferably has high fluidity and a long setting time. The fiber reinforced concrete, for example, powder of cement and silica, silica fume, silica sand, (concrete volume 1 m ³ per finished) unit water water superplasticizer
Compressive strength of 200 to 220 MPa, flexural strength of 40 to 45 MPa obtained by mixing about 2% by volume of high-strength steel fiber into a high-strength concrete matrix to which about 180 kg (water / cement ratio is about 22%) is added. , Adhesion strength 10-90 MPa, air permeability coefficient 2.5 × 10
^-18 m ² , water absorption 0.05 kg / m ³ , salt diffusion coefficient 0.0
Fiber-reinforced ultrahigh-strength concrete having characteristics of 2 × 10 ⁻¹² m ² / sec and an elastic modulus of 55 GPa can be used.

Hereinafter, a method for constructing a concrete structure will be described with reference to the drawings.

<A> Preparatory work As in the case of constructing a normal concrete structure, predetermined reinforcing bars and formwork 3 are assembled as required. The discharge unit 2 is arranged so as to be able to move in a direction in which the fiber is to be directed.

<B> Casting of concrete The fiber reinforced concrete 1 is poured into the form from the discharge portion 2 through, for example, a hose 22. Fiber 1 of fiber reinforced concrete passing between current plates 21
1 is arranged in the same direction as the current plate, in other words, in the flow direction of the fiber reinforced concrete. Then, the fibers 11 discharged from the discharge unit 2 are aligned in the drop direction and flow into the mold 3. Here, when the ejection unit 2 is moved in the direction in which the fibers are to be directed (A direction in FIG. 1), the fibers 11 are aligned in the movement direction of the ejection unit (A direction). The fiber reinforced concrete 1 discharged from the discharge portion due to the viscosity of the fiber reinforced concrete reaches the inside of the form without interruption. Therefore, the direction of the fibers 11 arranged by the current plate 21 during the fall is not disturbed. After the discharge unit 2 moves to the end of the formwork in the moving direction (for example, the A direction) and places the first layer of fiber-reinforced concrete, the direction of the discharge unit is rotated by 180 degrees, and the direction of the A direction is changed. The discharge section is moved in the opposite direction to cast the second layer of fiber reinforced concrete. After the second layer is cast, the same operation is repeated to cast fiber-reinforced concrete to the upper end of the formwork 3. Here, if you use fiber reinforced concrete with slow setting time,
The concrete structure can be integrated without separating the layers.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete structure constructed by a conventional method in which fiber-reinforced concrete of the same composition is poured from a hose into a form without using a straightening plate, and a concrete structure constructed according to the present invention are bent. The test was performed. The bending test was performed by simply supporting a specimen of a concrete beam constructed by the above two methods and applying a concentrated load to the center of the beam. FIG. 3 shows the test results.

FIG. 3 shows that the specimen of the present invention has a higher yield stress. In other words, even when the same material is used, it can be said that the bending strength is improved due to the difference in the construction method. Further, when observing the state of occurrence of cracks in the test specimen (crack diagram not shown), the test specimen of the present invention has more dispersed cracks, and the stress generated in the cross section is more uniform. Therefore, it can be said that a concrete structure in which local destruction is unlikely to occur could be constructed.

[0015]

[Effect of the present invention] Since the method for constructing a concrete structure of the present invention is as described above, the following effects can be obtained. <A> The direction of the fibers of the fiber-reinforced concrete can be adjusted by the flow straightening plate of the discharge unit, and the direction of the fibers can be arbitrarily set in the moving direction of the discharge unit. For this reason, it is possible to construct a concrete structure having excellent resistance to a load or deformation in a specific direction. That is, the effect of fiber reinforcement can be maximized. <B> The fiber direction of the fiber-reinforced concrete can be set to any direction only by changing the moving direction of the discharge section. For this reason, it is easy to partially align the fiber directions of the concrete structure. Moreover, in the concrete structure integrally constructed, the direction of the fiber can be easily designated arbitrarily by the portion. <C> The method for constructing a concrete structure of the present invention can be easily applied not only to a factory but also to a site. Further, since the equipment to be used has a simple structure and a simple structure, it can be constructed at low cost. <D> For example, in the case of a rigid frame structure, fibers are arranged in the same direction as the longitudinal direction of the tensile beam in the beam portion to be bent, and the even-angle portions serving as hinges at the time of fracture direct the fibers in various directions. The most effective reinforcing effect can be obtained by arranging them. Therefore, if a ramen structure is constructed by the method for constructing a concrete structure of the present invention, the fiber direction can be specified as described above.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a method for constructing a concrete structure according to the present invention.

FIG. 2 is a perspective view of an embodiment of a discharge unit having a shape that tapers in a discharge direction.

Fig. 3 Stress-displacement curve during bending test

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fiber reinforced concrete 2 ... Discharge part 21 ... Rectifier plate 3 ... Formwork

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Tanaka 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Inside Taisei Construction Co., Ltd. (72) Inventor Takefumi Shinto 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo No. Taisei Corporation F term (reference) 2E172 AA11 4G052 GA02 GA11 GB01 4G055 AA01 CA02 CA29

Claims (2)

[Claims] 1. A method for constructing a concrete structure in which fiber-reinforced concrete is poured into a formwork from a discharge portion, wherein a rectifying plate attached to the discharge portion is discharged in a direction in which concrete facing the rectifying plate is substantially parallel. A method of constructing a concrete structure, wherein the fiber reinforced concrete is poured into a form while the discharge section is moved in a predetermined direction while being attached at intervals in a direction substantially orthogonal to the above. 2. The discharge section to which the current plate is attached has a shape that tapers in a discharge direction.
A method for constructing a concrete structure according to claim 1.