JPH0839526A - Manufacture of pc product - Google Patents

Abstract

PURPOSE:To enable only an outer shuttering to be easily released by a method wherein concrete is placed in the shuttering to be compacted, and after dissolving an adhesive agent with alkaline water floating from the concrete, only the external shuttering is released. CONSTITUTION:When concrete 13 is placed in a shuttering 1 of an inner and outer double structure and compacted, an excess alkaline water content floats out to a surface from inside the concrete. An alkali-soluble emulsion adhesive agent 9 with which the outer shuttering 5 and the inner shuttering 3 are integrated is dissolved with the alkaline water content, and the outer shuttering 5 is separated from the inner shuttering 3. Therefore, only the outer shuttering 5 can be easily released. Since the inner shuttering 3 protects a PC semi-finished product in that case, neither flaws nor losses are not generated in the PC semi- finished product. Then, the outer shuttering 5 is used again just after releasing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing precast concrete (referred to as PC) products for various purposes.

[0002]

2. Description of the Related Art When constructing a building, if all the concrete is placed on-site, the construction period will be prolonged and the formwork will be disposable and difficult to reuse. A method of partially manufacturing and finishing parts such as columns is being promoted. This is because the construction period can be shortened by the amount of manufacturing and finishing at the factory, and the formwork can be reused repeatedly. A typical example of this method is a PC product.

As disclosed in Japanese Examined Patent Publication No. 1-15361, in order to improve the production efficiency of PC products, zero slump concrete is filled in a molding mold and placed on a vibrating table. A method has been proposed in which a semi-finished product of PC is obtained by pressing and pressing concrete without causing the shape of the concrete to be deformed even if the concrete is demolded early before hardening. This semi-finished PC product becomes a complete PC product after a certain curing period.

[0004]

However, early demolding is performed in a state where the concrete of the PC semi-finished product is not yet completely hardened, so that the surface of the concrete rubs against the mold surface and the PC semi-finished product is rubbed. There was a risk that the surface of the product would be scratched or damaged.

Therefore, conventionally, as a post-treatment for finishing the surface of a semi-finished PC product neatly, steam curing is performed after plastering by means such as a trowel, roller or spraying. However, such a post-treatment rather deteriorates the production efficiency of the semi-finished PC product.

The present invention has been made in order to solve the above problems, and is a PC product capable of obtaining a semi-finished PC product having no surface scratches or defects without post-treatment such as plastering. It is intended to provide a manufacturing method.

[0007]

In order to achieve the above object, the present invention mounts an inner mold made of a water-permeable sheet or paper inside an outer mold using an alkali-soluble emulsion adhesive. To form a double inner and outer formwork, cast concrete into the formwork to compact it, dissolve the adhesive with alkaline water that rises from the concrete, and then demold only the outer formwork to cure the concrete. It is characterized in that the inner form is removed from the mold after being cured.

[0008]

[Operation] When concrete is placed and compacted in a mold having an inner and outer double structure, excess alkaline water comes out from the concrete on the surface. With this alkaline water,
Since the alkali-soluble emulsion adhesive that integrates the outer mold and the inner mold is melted and the outer mold and the inner mold are separated from each other, only the outer mold can be easily demolded. At this time, since the inner frame protects the semi-finished PC product, the semi-finished PC product cannot be scratched or damaged. The outer formwork can then be reused immediately after being demolded. Since the inner frame is made of a water-permeable sheet or paper, it does not hinder the curing of concrete and does not damage the PC product even when it is removed from the mold.

[0009]

FIG. 1 shows an embodiment of the present invention.

As shown in FIG. 1 (A), the mold 1 of this embodiment has a double structure composed of an inner mold 3 and an outer mold 5. An inexpensive water-permeable sheet or paper is used for the inner mold 3. As the paper, for example, Octol (trade name of Mishima Paper Co., Ltd.) can be used. The outer form 5 is made of a material that has mechanical strength to support cast concrete and that can be disassembled and has a high degree of diversion, such as steel.
Then, the inner mold 3 is attached to the inner side of the outer mold 5 with an adhesive 9. An alkali-soluble emulsion adhesive is used as the adhesive 9. Further, a vacuum defoaming pipe 7 is connected to the outside of the outer frame 5 and is connected to a vacuum defoaming device (not shown).

This form 1 is, as shown in FIG.
A small slump concrete 13 is placed inside the vibrating table 11 while being placed on the table. Then, by applying fine vibration of high frequency of, for example, 25 KHz or more by the vibrating table 11 or by applying pressure by pressing, the cast concrete 13 is densely filled in the formwork 1 and compacted. To do. At the same time, the vacuum defoaming device defoams the cast concrete 13.
At this time, excess water in the concrete 13 comes out, but since the inner formwork 3 is made of a water-permeable sheet or paper,
The surplus water permeates or is absorbed by the inner mold 3. Therefore, the concrete 13 can be sufficiently compacted. If high-frequency vibration is applied as described above, the water in the concrete 13 can be released by this vibration, and dehydration and compaction can be performed at the same time.

Further, since the surplus water is alkaline, it permeates or is absorbed by the inner mold 3 and dissolves the adhesive 9 of the alkali-soluble emulsion system, whereby the outer mold 5 and the inner mold 3 are melted. The frame 3 is separated.

Thereafter, before the concrete 13 is hardened, the outer mold form 5 is demolded to obtain a PC semi-finished product 15 (FIG. 1).
(B)). At that time, the concrete 13 is sufficiently compacted and covered with the inner formwork 3, so that the PC
Not only is it possible to prevent the semi-finished product 15 from losing its shape, but also the surface of the semi-finished product 15 is not rubbed by the outer mold 5.

The removed outer mold 5 is cleaned (FIG. 1C). That is, the outer formwork 5 soiled with so-called slag of the concrete 13 is put in the cleaning tank 17 in a disassembled state, and the water 2 vibrating by the vibrator 19 is used.
The dirt 22 is removed by 1. Then, the outer formwork 5 together with another inner formwork 3 is reassembled and placed on the vibrating table 11 (FIG. 1 (E)), and the next concrete is immediately placed (FIG. 1 (A)). You can proceed to (See).

In the meantime, the PC semi-finished product 15 is protected by the inner formwork 3 for a certain period of time, and the concrete 13 is cured and hardened (FIG. 1 (B)). At this time, since the inner formwork 3 is made of a water-permeable sheet or paper, the curing of the concrete 13 is not damaged. And concrete 1
After fully curing 3, the inner mold 3 is demolded to obtain a PC product 23 (FIG. 1 (D)).

As described above, according to this embodiment, when the outer mold 5 made of steel is demolded, the adhesive of the alkali-soluble emulsion system in which the outer mold 5 and the inner mold 3 are united is integrated. Since the outer mold 5 and the inner mold 3 can be separated by dissolving the agent 9 with the alkaline excess water floating from the concrete 13, only the outer mold 5 can be easily demolded.

Further, since the inner mold 3 made of a water-permeable sheet or paper protects the PC half-finished product 15, the PC half-finished product 15 does not rub against the outer mold 5 and cannot be scratched or damaged. The expensive outer mold 5 to which the vacuum degassing pipe 7 is connected is
It can be reused immediately after being demolded early. Therefore,
With a small number of outer molds 5, manufacturing efficiency can be increased.

Further, since the inner mold 3 is made of a water permeable sheet or paper, not only does it prevent permeation or absorption of excess water and hinder the curing of the concrete 13, but also the inner mold 3 itself is removed due to its softness. The PC product 23 is not damaged during the molding.

[0019]

As described above in detail in the embodiments,
According to this invention, the following excellent effects are exhibited.

(1) When demolding the outer mold, an alkali-soluble emulsion-based adhesive that integrates the outer mold and the inner mold is dissolved by the alkaline excess water of the concrete, and then the outer mold is formed. The inner mold can be separated from the inner mold, and only the outer mold can be easily demolded.

(2) Since the inner mold made of a water-permeable sheet or paper protects the semi-finished PC product, it is possible to prevent the semi-finished PC product from being scratched or scratched on the surface by being rubbed by the outer mold. In addition, the inner mold does not impede the curing of concrete because it can permeate or absorb excess water, and because it is soft, it does not damage the PC product when the inner mold itself is demolded. There is no need for post-processing such as plastering.

(3) The outer mold can be reused immediately after being removed from the mold at an early stage, and the manufacturing efficiency can be improved.

[Brief description of drawings]

FIG. 1 shows steps for explaining an embodiment of the present invention, (A) is a step diagram for compacting poured concrete, and (B) is a step for demolding an outer formwork. Figure,
(C) is a process drawing of cleaning the demolded outer mold,
(D) is a process drawing for removing the inner mold, and (E) is a process drawing for assembling the cleaned outer mold.

[Explanation of symbols]

 1 Formwork 3 Inner formwork 5 Outer formwork 7 Vacuum defoaming pipe 9 Adhesive 11 Shaking table 13 Concrete 15 PC semi-finished product 17 Cleaning tank 19 Transducer 21 Water 22 Dirt 23 PC product

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location E04G 9/10 101 B (72) Inventor Tatsuya Wakisaka 4-640 Shimoseido, Kiyose City, Tokyo Obayashi Corporation Inside the Technical Research Institute (72) Inventor Fumihiro Inoue 4-640 Shimoseito, Kiyose-shi, Tokyo Inside Obayashi Corp. Technical Research Institute (72) Inventor Miki Aoyama 4-640 Shimo-Seido, Kiyose-shi Tokyo Metropolitan Institute of Technology (72) Inventor Yoshimasa Hayashi 4-640 Shimoseido, Kiyose-shi, Tokyo Within Obayashi Technical Research Institute, Inc. (72) Inventor Haruka Ogawa 4-640 Shimoseido, Kiyose-shi, Tokyo Within Ohbayashi Technical Research Institute (72) Inventor, Hajime Mitani Fusa, Tokyo, Kiyose City, Shimoseito 4-640, Obayashi Corporation Technical Research Institute

Claims (1)

[Claims] 1. An inner form made of a water-permeable sheet or paper is attached to the inside of the outer form using an alkali-soluble emulsion adhesive to form an inner-outer double form, and concrete is formed in the form. It is characterized in that the inner mold is demolded after the concrete is cured and cured by pouring and compacting it, dissolving the adhesive with alkaline water that rises from the concrete, and then demolding only the outer mold. PC product manufacturing method.