JPH0552036A - Formwork for concrete placing, sheet for formwork, and concrete placing method - Google Patents

Abstract

PURPOSE:To discharge excess water and bubbles in ready-mixed concrete through small holes in a synthetic resin layer and nonwoven fabric so as to uniformly remove them, obtain a concrete structure having uniform surface, so as to repeatedly use a formwork. CONSTITUTION:Concrete is placed by using formwork in which nonwoven fabric 3 is stuck on a woody board 1 a synthetic resin layer 4 is stuck on it, and many small holes 5 reaching the nonwoven fabric 3 are provided on the synthetic resin layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for placing concrete, a form sheet used for the form, and a method for placing concrete using the form.

[0002]

2. Description of the Related Art A formwork for placing concrete is generally constructed by using plywood. The ready-mixed concrete poured into the formwork has a high amount of mixed water to ensure fluidity,
Inevitably contains excess water. The traditional wood formwork is
It is preferable because it has the ability to absorb this excess water, and the air remaining on the surface in contact with the concrete formwork can also be passed to some extent, but the air permeability and water absorption of the plywood are not uniform, It is difficult to remove excess water and bubbles evenly.

It is known that a water-absorbent polymer material is stuck on plywood to enhance the water absorbency of the mold, but since the absorbed water is retained as it is, it is necessary to remove excess water. It is not expensive, and since this formwork cannot be used repeatedly, there are problems such as high construction costs, and it is not used often.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to sufficiently remove excess water and air bubbles when pouring concrete,
It is an object of the present invention to provide a formwork for concrete pouring that can be repeatedly used, a sheet for the formwork, and a concrete pouring method using the formwork.

[0005]

The formwork for placing concrete according to the present invention, as shown in FIG. 1, is a wooden board (1).
, A synthetic fiber non-woven fabric (3) is pasted with an adhesive (2), a synthetic resin layer (4) is pasted on the non-woven fabric, and a large number of small holes (5) reaching the non-woven fabric are formed in the synthetic resin layer. It will be provided.

It is convenient to use the following mold sheet for manufacturing the above mold. That is, as shown in FIG. 2, the form sheet of the present invention has a synthetic resin layer (4) attached to a synthetic fiber nonwoven fabric (3), and a large number of small holes ( 5) is provided.

The wood board may be made of the same material as that used for a conventional concrete casting form, such as plywood or particle board. The thickness of the wooden board may be the same as the conventional one.

As the adhesive, one that strongly adheres to the non-woven fabric is selected depending on the kind of the non-woven fabric. A material having high water absorption and water permeability is desirable.

As the non-woven fabric, known ones made of polyester, nylon, vinylon, polypropylene, polyethylene and the like may be used. Its thickness is, water flow effect is too thin becomes poor, since synthetic resin layer is too thick interlayer strength becomes weak easily peeled from the wooden board, and the basis weight in the range of 30 to 150 g / m ² Preferably. In particular, the non-woven fabric manufactured by the melt blow type or the spun bond type is preferable because it can increase the interlayer strength between the wooden board and the synthetic resin layer.

To apply the synthetic resin layer to the nonwoven fabric, polyolefin, vinyl resin, polyester, acrylic resin,
A method of laminating a sheet of polycarbonate or the like on the nonwoven fabric, or a method of extrusion coating polypropylene, polyethylene, ethylene-vinyl acetate copolymer, nylon, polyvinyl chloride, polyethylene terephthalate, ionomer or the like onto the nonwoven fabric may be used.
The thickness of the synthetic resin layer is appropriately in the range of 15 to 100 μm.

The size of the small holes is preferably large enough for water to pass therethrough and difficult for cement paste or sand to enter, and it is generally preferable to select from the range of 0.005 to 0.2 mm ^2. .. The shape of the holes is arbitrary.

When the number of small holes is small, water and air cannot be sufficiently discharged, and when the number is too large, it becomes difficult to remove the formwork from the concrete after curing. Choose it according to your needs.
Generally, it is recommended to set 1 to 100 pieces per cm ² .

To form the small holes in the synthetic resin layer, known means such as using a roll with needles may be used. When the needle is heated and punched while melting the synthetic resin layer,
Well-formed pores can be provided.

The concrete pouring method of the present invention using the above-mentioned mold is a concrete pouring method in which fresh concrete is poured into the mold and the mold is removed after curing of the concrete. As shown in FIG. 1, a synthetic fiber non-woven fabric (3) is adhered to the wooden board (1) with an adhesive (2), and a synthetic resin layer (4) is formed thereon.
Using a mold in which a large number of small holes (5) reaching the non-woven fabric are provided in this synthetic resin layer, excess water and air bubbles generated during concrete pouring are removed as shown in FIG. ) Through the small holes (5) and the non-woven fabric (3), and is absorbed by the wood board and discharged.

In FIG. 3, (7) is fresh concrete that has just been cast.

[0016]

The mechanism of discharging excess water and air bubbles will be described with reference to FIG. 3. Excess water and air bubbles discharged from the poured fresh concrete (7) pass through the small holes (5) and the nonwoven fabric (3). Reach The air and a part of the water that have reached the non-woven fabric move in the non-woven fabric surface, reach the joint of the formwork, and are discharged to the outside from there (the arrow indicated by the solid line). Part of the water absorbed by the non-woven fabric is absorbed by the wooden board through the adhesive (2) layer and is further discharged to the outside (arrow indicated by a broken line).
In this way, water and air are removed from almost every part of the surface of green concrete at about the same rate.

Since the surface of the mold which contacts the concrete is a synthetic resin layer, it can be easily peeled from the solidified concrete. Since the damage caused by peeling is negligible, this formwork can be used repeatedly.

[0018]

Example A polypropylene resin was extrusion-coated on a spunbonded non-woven fabric "E-1070" (made by Asahi Kasei) of polyester fiber having a basis weight of 70 g / m ² to a thickness of 50 μm.
m synthetic resin layer was formed.

The mold sheet of the present invention in which the above laminated sheet is perforated by combining a heating roll in which a large number of needles are planted and a rubber roll, and holes of 0.2 mm in diameter are provided in the synthetic resin layer at intervals of 5 mm in length and width. Got

As the wood board, plywood having a thickness of 12 mm used for a concrete pouring formwork was prepared. An adhesive agent of ethylene vinyl acetate emulsion was applied onto this wooden board, and the above-mentioned form sheet was adhered to obtain a form of the present invention.

A mold for placing concrete was constructed with this form. When ready-mixed concrete was poured into the mold and the mold was removed after curing the concrete, it could be easily peeled off. Use the same formwork to place similar concrete. 5
Repeatedly, the surface of each concrete was smooth and uniform.

[0022]

The formwork of the present invention has a high function of discharging excess water and air bubbles contained in poured concrete.
And withstands repeated use.

The concrete cast according to the method of the present invention has water peat, junker,
There are no defects such as sand streaks and bubbles, and the surface texture is uniform.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining the configuration of a mold of the present invention.

FIG. 2 is a view similar to FIG. 1 for explaining the form sheet of the present invention.

FIG. 3 is a view for explaining a mechanism of discharging excess water from the mold when the concrete pouring method of the present invention is carried out, showing an enlarged part near the seam of the mold. Cross section.

[Explanation of symbols]

 1 Wood board 2 Adhesive 3 Nonwoven fabric 4 Synthetic resin layer 5 Small hole 7 Fresh concrete

Claims (3)

[Claims] 1. A formwork for concrete pouring in which a nonwoven fabric made of synthetic fibers is adhered to a wooden board, a synthetic resin layer is stuck thereon, and a large number of small holes reaching the nonwoven fabric are provided in the synthetic resin layer. 2. A mold sheet comprising a synthetic resin non-woven fabric on which a synthetic resin layer is attached, and a large number of small holes reaching the non-woven fabric are provided on the synthetic resin layer. 3. A method for placing concrete, which comprises pouring ready-mixed concrete into a formwork and removing the formwork after curing the concrete. In the formwork, a nonwoven fabric made of synthetic fiber is bonded to a wood board as the formwork. A synthetic fiber layer is attached on top of the synthetic resin layer, and a formwork with a large number of small holes reaching the nonwoven fabric is used to remove excess water and air bubbles generated during concrete pouring. A concrete pouring method characterized in that the concrete is passed through the seams of the formwork and absorbed by the wooden board and discharged.