JPS5939289B2 - Manufacturing method of glass fiber piece reinforced concrete pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a concrete pipe reinforced with glass fiber pieces, and its purpose is to produce a concrete pipe with increased strength.

Concrete pipes of this type are generally produced by centrifugal compaction methods.

However, it is relatively weak in terms of certain mechanical strengths.

In recent years, efforts have been made to develop concrete pipes reinforced with glass fibers, but this has not always been satisfactory.

As a result of intensive research to address the above-mentioned conventional problems, the inventor completed this invention by focusing on the water that seeps into the inside of the formwork during centrifugal compaction.

In other words, glass fiber pieces and mortar are charged into a formwork that rotates in the circumferential direction, and then mortar with a low moisture content is charged so that the amount of water that is reduced is approximately the same as the water seeping out from inside the formwork. Then, glass fibers and mortar are again charged from the inside and molded.

As the glass fiber pieces in this invention, relatively short fibrous pieces, such as chopped strands, are used.

and exert maximum strength.

Further, when charging is carried out by spraying, fibers of a thickness and length within a range that is possible are used.

As the mortar, mortar, cement milk, or a mixture of these with a small amount of aggregate added thereto can be used.

In the second step, that is, after the mortar and glass fiber pieces are charged into the mold, mortar with little or no moisture is used.

In other words, it is adjusted so that the amount of water is reduced by approximately the same amount as the water that oozes out during compaction in the first step.

The reason for this is that the mortar in the second step is intended to absorb the moisture exuded in the first step.

On the other hand, various methods such as pouring or spraying can be used to charge the respective materials into the mold and form the layers.

If mortar and glass fiber pieces are to be charged by spraying, a spray gun is usually used.

Further, when spraying, centrifugal compaction is used, so there is a tendency for the particles to be uniformly dispersed in the end, but it is preferable to arrange a plurality of particles in the axial direction and the circumferential direction from the viewpoint of dispersibility.

Next, the present invention will be explained with reference to the drawings. In the drawing, 1 is a formwork, which is supported by rotating wheels 2, 2 and rotated.

Now, glass fiber pieces 3 and mortar 4 are charged into the formwork 1 by spraying with a spray gun 5 or by simply pouring a premix into the formwork 1.

This creates a surface area. In this case, the excess water contained in the surface layer gradually oozes out to the inside.

Next, a mortar 6 that has been mixed with a small amount of water of approximately the same level as this oozing water is sprayed into the spray gun 5.
Spraying with etc. forms an intermediate layer.

After that, the glass fiber pieces 3 and the mortar 7 are again
The inner layer is finished by spraying with the spray gun 5.

As described above, according to the present invention, since glass fiber pieces are mixed into the outer layer and the inner layer, the bending strength and impact resistance can be significantly improved.

In addition, since the water squeezed out during the formation of the surface layer is absorbed during the formation of the intermediate layer, material separation between the layers is prevented, consistency can be easily adjusted, and strength is improved. In addition, instead of making the whole thing an integral piece of mortar and glass fiber pieces, it is made of three layers and the middle layer is made only of mortar, so relatively expensive glass fiber pieces can be used. It is economical because it is not used.

Furthermore, since concrete pipes can be produced mainly by spraying, it is easier to produce than when rovings or strands are continuously wound in the same direction, or when a collar is wrapped in a shape.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the manufacturing method of the present invention, and FIG. 2 is a partially enlarged sectional view of a concrete pipe. 1... Formwork, 2... Rotating wheel, 3...
... Glass fiber pieces, 4 ... Mortars, 5 ... Spray guns, 6 ... Mortars, 7 ... Mortars.

Claims (1)

[Claims] 1. Glass fiber pieces and mortar are charged into a formwork that rotates in the circumferential direction, and then a moisture-free mortar is placed in the formwork, which has been adjusted to contain almost the same amount of moisture as the moisture seeping out from inside the formwork. 1. A method for manufacturing a glass fiber reinforced concrete pipe, which comprises the steps of: inserting glass fiber pieces into the pipe, and then charging glass fiber pieces and mortar again from the inside to form the pipe.