JPH0427621Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention is an improvement of metal formwork for concrete pouring, and particularly relates to a formwork that allows easy discharge of air and water from fresh concrete.

<Conventional technology><Problems to be solved by the invention> Recently, with the increasing scale of civil engineering and construction work, it has become necessary to pour fresh concrete into formwork from a high place or to pump fresh concrete over long distances. things are being done. For this reason, fresh concrete with extremely high moisture content and high slump is increasingly being used.

Concrete with such a large amount of moisture takes a long time to harden and develop strength.
In addition, the air in the concrete may not be fully discharged, or the concrete may have many voids, or the concrete may remain non-uniform with air bubbles remaining unevenly, or carbon dioxide may not be absorbed quickly. , there is a tendency for the life of concrete to be shortened due to the neutralized alkali aggregate reaction, so improvements are required. In order to solve this problem, for example, a foamed synthetic resin plate with open cells may be bonded to a metal plate that constitutes the flat part of a metal formwork using an adhesive, or an adhesive may be used to adhere the plate. There has been an attempt to exhaust the air and moisture in the concrete after it has been poured to the outside through open cells, but this method does not involve the use of adhesives or adhesives between the synthetic resin plate and the surface of the metal plate of the metal formwork. Since the agent obstructs the discharge of air and moisture from the fresh concrete, the discharge effect is limited to horizontal movement within the foamed synthetic resin board through the open cells within the board, and its discharge effect is extremely low.

Furthermore, the same drawbacks occur when a synthetic resin plate provided with a large number of micropores for ventilation and water permeability is simply adhered to a metal plate on the surface of a metal formwork.

Furthermore, in order to separate the metal formwork and the synthetic resin plate after the formwork is used for concrete pouring, if a synthetic resin with good mold releasability is selected and used, the metal plate of the metal formwork will be separated when the formwork is used. Since the adhesiveness between the surface of the plastic plate and the synthetic resin plate is poor, it is possible that the plastic plate will peel off due to friction from the poured concrete.In addition, the cost increase due to the use of a considerable amount of adhesive or adhesive is unavoidable. Moreover, there are problems such as the possibility that the microfoam holes for degassing and drainage may become clogged and lose the discharge function.

This invention aims to solve such problems.

<Means for solving the problem> This invention was made as a result of intensive study in view of the above-mentioned circumstances, and its outline is as shown below.

Ribs constituting at least both side edges, preferably longitudinal ends, of the metal formwork are provided leaving ears of a certain width, and the flat surface of the formwork has micropores that allow ventilation and water permeability. A concrete formwork in which the edge of a plastic sheet is engaged with and adhered to the ear part, and a formwork similar to the above, the flat part of which is made of a metal plate, and a ventilation hole that covers this formwork. This formwork for concrete is made by bonding the edge of a plastic sheet having water-based micropores to the ear portion. The edge of the plastic sheet, which has micropores that allow ventilation and water permeability, can be fitted and bonded to the ears of the metal form by heating with a torch lamp or the like, but intermittently, an adhesive can be used. It can also be used together with screws.

<Function> According to this invention, air and moisture in fresh concrete migrate to the back side of the plastic sheet through the micropores of the same sheet (if there is a metal plate, it migrates between the metal plate and the plastic sheet), and quickly is discharged outside.

Plastic sheets used here include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polycarbonate, ABS,
Acrylic resin, styrene acrylate copolymer,
A flexible sheet of styrene acrylonitrile copolymer and polyester is used, and the tensile strength is 70~
Anything over 80kg/ ^mm2 can be used for practical purposes. Further, the thickness is preferably 0.1 to 5.0 mm.

The micropores provided in the plastic sheet must be such that the contact angle with water is 10 degrees or more, for example, the pore diameter is 0.1.
It is preferable to have a large number of slits of 10 mm to 50 mm in the longitudinal direction.

Further, the width of the ear part of the metal form is not particularly limited, but a width of about 1 to 20 mm is advantageous for bending the side edges of the plastic sheet, heating molding, and thermal bonding.

<Example> Fig. 1 (perspective view) and Fig. 2 (end sectional view) show an example of the formwork of the present invention. It is provided. Other medium vertical ribs 3 as well as normal metal formwork,
A horizontal rib 4 and a middle horizontal rib 5 are provided, and 6 is a hole for a clip or bolt. In the present invention, a plastic sheet 7 having air permeability and water permeability (not shown) is attached to the metal formwork so that its edge part engages and covers the ear part 2a of a constant width of the metal formwork. It is then heated and glued.

If you assemble multiple pieces of this type of formwork depending on the purpose and pour wet concrete into it,
Air and moisture quickly escaped to the outside through the back side of the plastic sheet, and the concrete became a uniform homogeneous body that hardened relatively quickly and produced a high-strength concrete product.

Further, after use, this formwork can be easily separated from the ears of the metal formwork and dismantled by simply heating the edges of the plastic sheet. Moreover, this sheet can withstand reuse in formwork.

Fig. 3 (perspective view) and Fig. 4 (end sectional view) show another example of the formwork of the present invention, in which a metal plate 1 is provided on the flat part of the metal formwork, and the metal plate 1 has a fixed width. Vertical ribs 2 are provided except for the ear portions 2a.
In addition, similar to the metal formwork shown in FIG. 1, there are provided a medium vertical rib 3, a horizontal rib 4, and a medium horizontal rib 5, and 6 is a hole for a clip or bolt. The present invention is such that a plastic sheet 7 having air permeable micropores (not shown) engages and covers the edge portion of the metal formwork with a predetermined width ear 2a of the metal formwork. It is then heated and glued. Note that it is permissible to partially use an adhesive adhesive for adhesion because it does not interfere with the exhaust and drainage functions.

Further, it is preferable to apply corrugation processing, plastic processing, etc. to the adhesive surface of the plastic sheet to the metal surface in order to make drainage work more effectively, and it is also possible to partially adhere the plastic sheet to the metal surface.

If you assemble multiple pieces of this type of formwork depending on the purpose and pour wet concrete into it,
Air and moisture quickly escaped to the outside through the gap between the metal formwork and the plastic sheet, and the concrete became a uniform homogeneous body that hardened relatively quickly and produced a high-strength concrete product.

Further, after use, this formwork can be easily separated from the ears of the metal formwork and dismantled by simply heating the edges of the plastic sheet. Moreover, this sheet can withstand reuse in formwork.

In carrying out the present invention, the structure of the ears of the metal form is not limited to a simple flat plate-like structure as shown in the drawings.

<Effects of the Invention> As described above, this invention is characterized in that the flat parts of the metal formwork are made up solely of a plastic sheet having micropores for ventilation and water permeability, or of a metal plate and a plastic sheet having micropores for ventilation and water permeability covering its surface, and since the plastic sheet is only attached to the metal formwork at the ear parts, deaeration and dehydration of the fresh concrete is carried out quickly, improving work efficiency at a relatively low cost and enabling the production of high-quality hardened concrete.

Furthermore, after the mold is used, it goes without saying that if the plastic sheet is bonded to the ears by heating, it can be easily separated by heating.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of the formwork of the present invention, Fig. 2 is a sectional view of the end face of Fig. 1, Fig. 3 is a perspective view showing another example of the formwork of the invention, and Fig. 4 is FIG. 4 is a sectional view of the end face of FIG. 3; 1... Metal plate, 2... Vertical rib, 2a... Ear part,
3... Middle vertical rib, 4... Horizontal rib, 5... Middle horizontal rib, 6... Hole for clip or bolt, 7... Plastic sheet.

Claims (1)

[Claims for Utility Model Registration] 1. A metal formwork in which ribs constituting at least both end portions in the vertical direction are provided inside ears of a constant width, and a flat part of the formwork, and 1. A formwork for concrete comprising a plastic sheet having holes for ventilation and water permeability, the ends of which are engaged with and tightly adhered to the ears. 2. The ribs constituting at least both end portions in the vertical direction cover a metal formwork provided inside an ear portion of a constant width and a metal plate on a flat part of the formwork, and the ribs forming at least both end portions in the vertical direction A concrete formwork comprising a plastic sheet having holes for ventilation and water permeability, which are engaged with and tightly attached to the ears.