JPS5857286B2 - Kneading method for steel fiber reinforced concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for kneading steel fiber reinforced concrete, and more particularly to a method for adding steel fibers to concrete slurry.

The most important consideration in determining the mix of steel fiber reinforced concrete is the uniform fraction of steel fibers in the concrete.

This word becomes more important as we try to increase the strength of concrete by increasing the amount of steel fiber blended.

During kneading of steel fiber concrete, separation of steel fibers and formation of ball-shaped agglomerates are likely to occur.

Ball-shaped nodules are formed of only steel fibers, steel fibers and paste, steel fibers and sand grains, steel fibers and mortar, etc., and once a nodule is formed, it is difficult to disperse it again.

The formation of such ball-shaped agglomerates significantly reduces the strength of steel fiber reinforced concrete.

Therefore, the most important condition is to prevent the formation of such nodules when mixing steel fiber concrete.

Steel fibers are generally packaged and transported, and when they arrive at the site of use, they are entangled and have a lump-like appearance. Therefore, if a small amount is used, it is inputted, and if a large amount is used, it is processed by a machine such as a dispenser or vibrating screen. After that, it is poured into concrete slurry.

In this way, the formation of nodules during mixing can be generally avoided, but unless the steel fibers loosened by manual or mechanical power are immediately introduced into the mixer, they will become entangled again. Corresponding unpacking/
A pick-up facility is required.

For example, in a batcher plant having a 1000 ton forced stirring type mixer, it is necessary to use approximately 3 dispensers with a capacity of 40 to 50 kg/min, and the human power for unpacking and loading is also required for 3 machines.

The purpose of this invention is to provide a kneading method that efficiently introduces steel fibers into concrete slurry without forming nodules during kneading, and which can uniformly and randomly distribute steel fibers in concrete. There is something to do.

The method for crossing wires in steel fiber reinforced concrete according to this invention is as follows:
This method is characterized in that a pretreatment is performed to align the steel fibers in one direction, and the aligned steel fibers are randomly oriented through a grid or a sieve and then introduced into concrete slurry.

In the method of the present invention as well, the steel fibers packed and transported are removed by Spencer or the like, as in the general case.

In the method of this invention, the thus loosened steel fibers are pretreated to be oriented in one direction.

As an example of the pretreatment method, a container 2 having a large number of vertical partitions as shown in FIG. It is guided through the vertical gutter 3 and aligned within the vertical partition 4.

Further, as shown in FIG. 2, the steel fibers 1 falling from a dispenser or the like may be oriented by magnetic force in a container 2a which is buttoned in a magnetic field formed by a magnet 5.

The steel fibers thus oriented then fall directly into the concrete mixer through a grid or sieve whose openings are slightly larger than the length of the steel fibers themselves, and then onto a conveyor where they are passed through the conveyor. Pour into concrete mixer.

The oriented steel fibers are passed through a grid or sieve so that they are randomly oriented and then fed into a concrete mixer.

The method of the present invention is constructed as described above, and the steel fibers loosened by the dispenser do not get mixed up during storage.
Steel fibers can be loosened in advance with a dispenser and then added according to the capacity of the mixer.

Therefore, the capacity can be increased compared to the case of directly dispensing from a conventional dispenser.

Furthermore, in the method of the present invention, the steel fibers are oriented in a grid or sieve and fed into the mixer, so there is no risk of separation or formation of nodules, and the steel fibers are uniformly and randomly distributed in the concrete. distribution.

When mixing steel fibers into concrete, it is generally accepted that mixing them at random and uniform intervals is the most important thing for reinforcement, but in the method of this invention, This idea is unique, as it includes pre-processing to orient it in one direction once it is standing.

Next, an example will be described.

Mild steel fibers of 0.5 x 0.5 x 30 mm (trade name: TESUSA (manufactured by Nippon Kokan KK)) were used as steel fibers, and were mixed into concrete at a volume ratio of 1.5 (118 kQ/m3).

The steel fibers that can be dropped into the dispenser are shown in Figures 1 and 2.
After pretreatment in the container shown in the figure, sieve with a two-stage sieve of 5 (m x 5 (m) 1 ooo,
The concrete was dropped onto IHI Iberg and mixed with steel fiber reinforced concrete.

It was confirmed by the JIS aggregate washing test that no lumps were formed in the concrete obtained, and the dispersion state of steel fibers in the concrete was good.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams of a container in which pretreatment is performed in the method of the present invention. In the diagram, 1 is the steel fiber, 2 and 2a are the containers, 3 is the downspout, and 4
is a vertical partition, and 5 is a magnet.

Claims (1)

[Claims] 1. The method is characterized in that a pretreatment is performed to align the falling steel fibers in one direction, and the aligned steel fibers are randomly oriented through a grid or a sieve before being introduced into concrete slurry. A method for mixing steel fiber reinforced concrete. 2. The method of intermixing steel fiber-reinforced concrete according to claim 1, wherein the pretreatment involves directing the falling steel fibers through a hopper having a large number of vertical partitions at intervals slightly narrower than the length of the steel fibers. 3. The method for kneading steel fiber-reinforced concrete according to claim 1, wherein the pretreatment comprises receiving the falling steel fibers in a non-magnetic container placed in a magnetic field and orienting them by magnetic force.