JPH028009A - Centrifugal molding of fiber reinforced concrete product - Google Patents

Abstract

PURPOSE:To make a large powered pump and a large diameter inlet pipe unnecessary and enhance the reinforcing effect of a concrete product by a method wherein reinforcing fibers and concrete are poured independently in a centrifugally casting concrete form and, after that, mixed with each other by rotating the concrete form. CONSTITUTION:A cylindrical busket-shaped reinforcement is concentrically arranged in a set by cylindrical centrifugal molding bisect concrete forms. Further, a fiber feeding conveyer for carrying steel reinforcing fibers is horizontally arranged at one end side of the concrete form. Steel fibers are dropped continuously from the tip of the fiber feeding conveyer in the concrete form. After that, in place of the tip of the fiber feeding conveyer, the opening of the tip of a concrete inlet pipe is inserted at one end of the central part of the cylindrical busket-shaped reinforcement in the concrete form in order to continuously pour the required amount of concrete over the whole length of the concrete form. After that, the concrete from containing the reinforcement, steel fibers and concrete therein is rotated about its central axis.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for centrifugally forming a fiber-reinforced concrete product in which reinforcing fibers such as steel fibers, glass fibers, carbon fibers, etc. are mixed into concrete.

<Conventional technology> When centrifugally forming cylindrical steel H & fiber-reinforced reinforced concrete products, concrete with steel fibers mixed in is prepared by mixing concrete components such as cement, water, and aggregate with reinforcing steel fibers. do.

On the other hand, inside the cylindrical formwork for centrifugal forming, reinforcing bars in the original cylindrical shape are arranged concentrically, and the opening at the tip of the injection tube is inserted into the center of the cylindrical cage-shaped reinforcing bars in the formwork. .

The concrete mixed with the above steel H1im is
Concrete mixed with steel fibers is placed throughout the formwork by pumping it into the injection pipe and injecting it into the formwork through the opening at the tip of the injection pipe.

The formwork with reinforcing bars placed and concrete mixed with steel fibers poured into it is placed in a centrifugal forming machine, which rotates around the central axis, and the concrete mixed with steel fibers in the formwork is subjected to centrifugal force due to the rotation of the formwork. Using this method, the steel is compacted and formed into a cylindrical shape in which the cylindrical cage-shaped reinforcing bars are embedded.

After that, the cylindrical concrete with the steel fibers in the formwork mixed in and the reinforcing bars buried is cured in steam, demolded, and the cylindrical concrete with the steel fibers mixed in and the reinforcing bars buried is cured in the air. Then, a cylindrical steel fiber reinforced concrete product is obtained.

<Problems to be Solved by the Invention> However, when reinforcing fibers such as steel fibers, glass fibers, carbon fibers, etc. are mixed into concrete, the fluidity decreases, and when the amount of reinforcing fibers mixed in increases, concrete becomes less fluid. , the fluidity further decreases.

Therefore, there is a limit to the amount of reinforcing fibers mixed in, and the maximum amount of reinforcing fibers mixed in is about 2% based on the volume 8I ratio.

In the above-mentioned centrifugal forming method for steel fiber reinforced concrete products, since concrete mixed with steel fibers has low fluidity, it is best to pump the concrete mixed with steel fibers into the injection pipe and inject it into the formwork. Have difficulty.

That is, to pump concrete mixed with steel fibers, a high-power pump and a large-diameter injection pipe are required.

Furthermore, since the maximum amount of steel fibers mixed in is about 2%, which is very small, the reinforcing effect of steel fibers in concrete products is low, and the reinforcing effect of steel fibers cannot be enhanced.

Moreover, since the same steel fiber mixed concrete is placed in all parts of the formwork, the concrete product is made of steel fibers.
Steel m male is mixed not only in parts that require reinforcement with IT, but also in parts that do not require reinforcement with steel fibers,
All the steel is wasted.

An object of the present invention is to solve the conventional problems as described above.

Means for Solving the Problems> The present inventor focused on the fact that the above problems are caused by the fact that concrete mixed with reinforcing fibers is pumped into a centrifugal molding form, and developed a method for centrifugal molding. He came up with the idea of placing reinforcing fibers and concrete separately in a formwork, then rotating the formwork to mix the reinforcing fibers and concrete in the formwork.

That is, in the present invention, reinforcing fibers and concrete are placed separately in a centrifugal molding mold, the mold is rotated, the fibers in the mold and concrete are mixed, and the fibers in the mold are mixed. This is a centrifugal forming method for fiber-reinforced concrete products, which is characterized by compacting and molding mixed concrete to obtain fiber-reinforced concrete products mixed with fibers.

In addition, the present invention is characterized in that, in the centrifugal molding method for fiber-reinforced concrete products, one fiber is placed only in a desired part within the formwork, thereby obtaining a concrete product in which the fibers are mixed only in the desired parts. This is a centrifugal molding method for fiber-reinforced concrete products.

Function> In the centrifugal forming method for fiber-reinforced concrete products of the present invention, reinforcing fibers and concrete are placed separately in a formwork for centrifugal forming, and as the formwork rotates, the fibers and concrete in the formwork are separated. are mixed.

Therefore, there is no need to pump concrete mixed with reinforcing fibers into the formwork.

Moreover, m! of the present invention! In the centrifugal molding method for I-reinforced concrete products, H&male is placed only in desired areas within the formwork, resulting in a concrete product in which #1m is mixed only in desired areas.

Therefore, the reinforcing fibers are mixed only in the parts of the concrete product that require fiber reinforcement, and not in the parts that do not require fiber reinforcement.

<Effects of the Invention> In the centrifugal molding method for m-male reinforced concrete products of the present invention, there is no difficulty in pumping concrete whose fluidity has decreased due to the mixing of reinforcing fibers into the formwork.

Therefore, unlike the conventional forming method in which concrete mixed with reinforcing fibers is pumped into a mold, a high-power pump for concrete and a large-diameter injection pipe are not required.

Furthermore, by increasing the amount of reinforcing fibers put into the formwork, it is possible to enhance the reinforcing effect of the concrete product.

Furthermore, in the centrifugal forming method of FA fiber-reinforced concrete products of the present invention, reinforcing TA fibers are not mixed into parts of the concrete product that do not require fiber reinforcement, so reinforcing M fibers are wasted. Not done.

<Example> The centrifugal molding method of fiber-reinforced concrete products in this example is applicable to balls of power transmission lines, communication lines, traffic lights, traffic sign boards, etc., and cylindrical steel fiber-reinforced reinforced concrete products such as piles, also called piles. This is an example of centrifugal molding.

A two-part cylindrical formwork for centrifugal molding is arranged horizontally, and cylindrical cage-shaped reinforcing bars are arranged concentrically within the formwork.

Further, on one end side of the formwork, a fiber supply conveyor for transporting reinforcing steel H&male is arranged horizontally along the direction of the central axis of the formwork. The tip of the fiber supply conveyor is inserted into one end of the center of the cylindrical cage-shaped reinforcing bar within the formwork.

When mixing steel fibers over the entire length of the reinforced concrete product, the fiber supply conveyor is continuously driven.
Steel fibers can be continuously dropped from the tip of a fiber supply conveyor that continuously transports steel fibers.

On the other hand, the formwork with reinforcing bars placed thereon is continuously moved along the direction of the central axis toward the fiber supply conveyor.

The tip of the fiber supply conveyor that is being driven is moved relatively from one end to the other end within the formwork.

Then, a desired amount of steel fibers is continuously distributed and arranged over the entire length of the formwork.

In addition, if steel fibers are mixed only in the parts of the reinforced concrete product that require reinforcement with steel fibers, and if steel fibers are not mixed in the parts of the reinforced concrete product that do not require reinforcement with steel fibers, the inside of the formwork may be The fiber supply conveyor is driven to drop the steel fibers from the tip of the MRA supply conveyor only while the tip of the fiber supply conveyor, which is moving automatically, passes through the part of the formwork that requires reinforcement with steel fibers. While the tip of the supply conveyor passes through a portion of the formwork that does not require reinforcement with steel fibers, the drive of the fiber supply conveyor is stopped to prevent steel fibers from being layered from the tip of the fiber supply conveyor.

Then, a desired amount of steel fibers is scattered and arranged only in the parts of the formwork that require reinforcement with steel fibers, and the steel fibers are not spread in parts of the formwork that do not require reinforcement with steel fibers.

After placing the steel jar in the formwork, the opening at the end of the concrete injection pipe is inserted into one end of the center of the cylindrical cage-shaped reinforcing bar in the formwork, instead of the end of the m-fiber supply conveyor.

Then, concrete ingredients such as cement, water, and aggregate are mixed to prepare concrete that does not contain reinforcing steel fibers, and this concrete is pumped into the concrete injection pipe. Let it flow out from the opening at the tip.

On the other hand, the formwork containing the reinforcing bars and steel fibers is moved continuously along the direction of the central axis toward the concrete injection pipe, and the opening at the tip of the concrete injection pipe is opened from one end of the formwork to the other. Move relative to the edge.

The desired amount of concrete is then continuously poured and placed over the entire length of the formwork.

The formwork containing the reinforcing bars, steel fibers, and concrete is then placed in a centrifugal forming machine and rotated around a central axis.

At the first stage, the rotation speed of the formwork is set to a speed suitable for mixing the steel m, m and concrete in the formwork, and the steel fibers and concrete in the formwork are centrifuged by the rotation of the formwork. Mix using force.

In the next step, the rotation speed of the formwork is set to a speed suitable for compacting the concrete mixed with steel fibers in the formwork, and the concrete mixed with steel fibers in the formwork is rotated. Using centrifugal force, the steel is compacted and formed into a cylindrical shape in which the cylindrical blind-shaped reinforcing bars are embedded.

After the concrete mixed with steel fibers in the formwork is centrifugally formed, the cylindrical concrete in which the steel fibers in the formwork are mixed and the reinforcing bars are buried is cured in steam, demolded, and then After curing in the atmosphere, a cylindrical steel fiber-reinforced reinforced concrete product is obtained.

In this steel fiber-reinforced reinforced concrete product, when steel fibers are placed continuously over the entire length of the formwork, the steel fibers are mixed along the entire length, and the entire length is reinforced by the steel fibers.

In addition, if steel fibers are placed only in parts of the formwork that require reinforcement with steel fibers, and if steel fibers are not placed in parts of the formwork that do not require reinforcement with steel fibers, In reinforced concrete products, steel U7J is mixed only in the parts that require reinforcement with steel fibers, and only the parts that require reinforcement with steel fibers are reinforced.

Steel fibers are not mixed in parts of steel fiber-reinforced reinforced concrete products that do not require reinforcement with steel fibers, and those parts are not reinforced with steel fibers.

That is, the reinforcing steel fibers are not wasted.

In addition, in reinforced concrete products, the parts that require reinforcement with steel fibers are parts where large stress is generated, such as the boundary between the above-ground part and the underground part of a pole installed on the ground surface.

In the centrifugal forming method for fiber-reinforced concrete products in this example, concrete without reinforcing fibers is pumped into the concrete injection pipe, so the concrete injection equipment such as the pump and concrete injection pipe is The usual one used when centrifugally forming concrete products without fibers mixed in is used as is.

Modified example> In the centrifugal forming method for fiber-reinforced concrete products in the example, a fiber supply conveyor is placed at the center of the cylindrical blind-shaped reinforcing bars in the formwork to disperse reinforcing fibers into the formwork. I have inserted it here, but you can do the following instead.

After cylindrical blind-shaped reinforcing bars are arranged concentrically in the semi-cylindrical lower mold of a horizontally arranged two-part centrifugal molding frame, reinforcing fibers are inserted from the upper position of the lower mold to the lower mold. After scattering the reinforcing fibers by dropping them into the mold, the semi-cylindrical upper mold of the formwork is placed over the lower mold containing reinforcing bars and reinforcing fibers and fixed.

Further, in the centrifugal molding method of the fiber-reinforced concrete product of the example, steel fibers were used as reinforcing fibers, but instead of this, glass fibers, carbon fibers, etc. may be used.

Procedural amendment dated July 27, 1988■ Indication of the case Patent Application No. 158928 of 1988 2 Name of the invention Centrifugal molding method for fiber-reinforced concrete products 3 Person making the amendment Relationship to the case Patent applicant Minato Ward, Nagoya City Shiokaze Town (Place No. 10) Tokai Concrete Kogyo Co., Ltd. Representative Sumi Kuraoka 4 Agents 6 Number of claims increased by amendment 7 Subjects of amendment 1 + 1 envoy) "Electrical lines, communication lines," shall be corrected to "power transmission lines, distribution lines, communication lines,"

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Claims (1)

[Claims] 1. Put reinforcing fibers and concrete separately into a centrifugal molding mold, rotate the mold, mix the fibers in the mold with concrete, and mix the fibers in the mold with concrete. A centrifugal forming method for fiber-reinforced concrete products, which is characterized by compacting and forming concrete mixed with fibers to obtain fiber-reinforced concrete products mixed with fibers. 2. The centrifugal molding method for fiber-reinforced concrete products according to claim 1, characterized in that the fibers are arranged only in desired portions within the formwork to obtain a concrete product in which fibers are mixed only in the desired portions. 3 Place cylindrical cage-shaped reinforcing bars in a cylindrical formwork for centrifugal forming, add reinforcing fibers and concrete separately, and rotate the formwork around its central axis to fill the inside of the formwork. The fibers from the formwork are mixed with concrete, and the concrete mixed with the fibers in the formwork is compacted and formed into a cylindrical shape in which the reinforcing bars are buried.Then, the concrete is made into a cylindrical shape in which the fibers in the formwork are mixed and the reinforcing bars are buried. A centrifugal forming method for fiber-reinforced concrete products, which is characterized by curing and demolding to obtain a cylindrical fiber-reinforced reinforced concrete product mixed with fibers.