JPH0529741B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a covering material for formwork that can significantly increase the conversion rate of wooden concrete formwork and that is less likely to cause air bubbles or blisters on the concrete surface. .

[Conventional technology]

Plastic film is applied to the surface of the formwork in order to improve the releasability of the formwork and avoid adhesion of concrete to it, to have a positive effect on the feel and texture of the concrete surface, and to increase the reuse rate of the formwork. Many have been proposed with . However, plastic film has excellent waterproof properties and is not breathable, so air bubbles and blisters form on the concrete surface that comes into contact with the film due to stagnation of air and water, leaving traces on the concrete surface. The cavity remains unsightly. Therefore, it has been proposed to open pores in the plastic film to provide ventilation and water permeability (Jitsukai Sho.
50-70729).

〔Problems to be solved〕

However, even in the above-mentioned conventional example, the release of air and water (exhaust/drainage performance) from the concrete surface was not perfect. For this reason, on the concrete surface, the occurrence of cavities that must be repaired is unavoidable.

When we investigated the cause, we found that as a result of the plastic film being thermally welded or glued to the concrete formwork, the pores become clogged and sealed by the surface of the concrete formwork, resulting in a loss of ventilation and water permeability. Ta. In other words, even if the concrete formwork is made of wood and has air permeability and water permeability, it is limited to the pores at most, so the air permeability is negligible or non-existent. It will be equal to

The present invention was developed in view of the above circumstances, and when used by adhering to concrete formwork, the exhaust and drainage properties of the adhesive surface of the concrete are very good, making it difficult for air bubbles and blisters to form on the concrete surface. The purpose is to provide covering materials for formwork.

[Means to solve the problem]

In order to achieve the above object, the present invention has a structure in which a water-resistant film, foil or sheet is used as a formwork covering material that is removably applied to a concrete formwork in order to improve its releasability from concrete. is the outer layer, and on the back side of this outer layer is cardboard base paper,
It is made by laminating water-absorbing base materials such as kraft paper, cardboard sheets, cardboard, water-absorbing fibrous materials, and water-absorbing polymer materials, and is formed by scattering countless pinholes that pass through both the outer layer and the base material. The gist of the present invention is a formwork covering material formed in a shape that removably covers the front side of the formwork except for the back side.

[Effect]

Since the formwork sheathing material is configured as described above, when concrete is poured between the sheathing materials covering the surface side of the formwork, air and excess water in the concrete at the boundary with the outer layer will not form pinholes. When the air flows in, the base material with high ventilation and water permeability is exposed on the inner peripheral surface of the pinhole, so air intake and water flow into the base material.
Water is absorbed. Moreover, since it is not bonded to the surface of the concrete formwork and is simply in surface contact with it, exhaust and drainage are carried out along the contact surface.
As a result, air and water will be sucked into the concrete formwork over a wide area.

Pinholes can be formed using an extremely simple method, for example, by protruding a large number of pins on the outer circumferential surface of a press roll and inserting a covering material consisting of a waterproof layer and a base material under the press roll. If possible, if press rolls with different pin diameters, protruding dimensions, arrangement intervals (densities), etc. are prepared or made adjustable, the degree of pinholes can be appropriately selected.

The waterproof layer can be made of films such as plastic film, foamed film, perforated plastic film, or aluminum vapor-deposited film, or metal foils such as aluminum foil or iron foil, as well as airtight cloth, closed-cell plastic foam sheet, or soft plastic. Examples include sheets such as sheets.

Base materials include kraft paper, corrugated liner base paper, corrugated paperboard, paperboard, various water-absorbing and moisture-absorbing papers, water-absorbing non-woven fabrics, water-absorbing cloth, woven and non-woven fabrics made of water-absorbing polymer fibers, and water-absorbing polymer materials. A so-called water-absorbing polymer material such as a sheet is used.

Basically, pinholes are formed on substantially the entire surface of the coating material.

〔Example〕

Next, embodiments will be described with reference to the drawings.

The coating material 1 according to the embodiment of the present invention shown in FIGS. 1 to 3 is constructed in the shape of a truncated quadrangular pyramid box consisting of a top wall 2 and a side peripheral wall 3, and is provided on the surface 5 side of a formwork 4 in the direction of the arrow. It is used by covering it.

That is, the top wall 2 and side wall 3 of the covering material 1 are made to correspond to the approximately same size as the surface 5 of the formwork 4 and the side surface 7 including the crosspieces 6, respectively, and the surface 5 of the formwork 4 is
It is shaped like a truncated quadrangular pyramid box so that it can be easily put on from the sides. This box state can be easily fixed by staples or the like.

As a result, the covering material 1 can cover the front side of the formwork 4 except for the back side 8, and after covering, the covering material 1
Important points of the side peripheral wall 3 may be appropriately fastened to the crosspieces 6 of the formwork 4 with staples or adhesive tape.

As shown in FIG. 2, the covering material 1 can be stored and transported in the unfolded state and is easy to install. That is, it is sufficient to simply bend the dotted line portions of the formwork 4 and properly fix the side peripheral wall 3 to the formwork side surface 7, making it possible to cover the formwork 4 easily and accurately.

This coating material 1 is a laminate of an outer layer 10 and a base material 11, as shown in the partial cross-sectional view of FIG. Constructed of waterproof material. That is, the outer layer 10 is a waterproof layer and is made of a film or sheet made of plastic such as polyethylene, polypropylene, or polystyrene, or a metal foil such as aluminum foil.

Further, the base material 11 is made of a paper base material that is inexpensive and easy to process, such as cardboard base paper or kraft paper.
Note that the base material 11 may be a so-called water-absorbing polymer material, such as a cloth made of water-absorbing polymer fibers or a sheet made of a water-absorbing polymer material.

In the present invention, pinholes 15 are formed in the outer layer 10, that is, the waterproof layer, so as to be scattered at equal intervals vertically and horizontally.

In the case of the embodiment shown in FIG. 3, if the inner surface of the base material 11 is waterproofed by water-repellent treatment, lamination with plastic film, or plastic coating,
Even when moisture such as rain enters the front side of the formwork 4 through the holes 9 from the back side of the formwork 4, the inner side of the covering material 1 is also water resistant, which is more preferable.

That is, when the paper of the base material 11 gets wet due to moisture intrusion on the inner surface side, the paper stretches accordingly, and the film of the outer layer 10 is also partially stretched, resulting in wrinkles. By waterproofing the fabric as described above, the occurrence of wrinkles can be prevented.

Furthermore, by configuring the outer layer 10 as a biaxially stretched polypropylene film layer with very little expansion and contraction, the generation of wrinkles can be further prevented.

In addition, the covering material 1 is not limited to such film laminated paper, but also aluminum foil laminated paper,
The object of the present invention can be achieved even with a corrugated cardboard sheet whose surface is provided with water resistance and slipperiness by the outer layer 10, or even with a paperboard on which the outer layer 10 is laminated.

The pinhole 15 allows the pin to pass through the base material 11, and the through hole 13 of the pinhole 15 is provided in the base material 11.

FIG. 4 shows, with arrows, the discharge routes of air and excess water in the concrete C poured into the concrete formwork 8 when the formwork covering material 1 is in use. Although the surface of the concrete formwork 8 and the base material 11 are in close contact, since both have ventilation and water permeability, it can be considered that a minute gap 18 is created between them.

Therefore, when the air and water in the concrete C enters the pinhole 15 as shown by the arrow, it permeates widely to the back surface through the base material 11 and the gap 18, and as a result, it spreads over a wide area of the formwork. Since air and water are absorbed into the surface, air bubbles and water bubbles will not form inside the concrete. And when the formwork was removed,
A clean concrete surface with no cavities can be obtained.

〔Effect of the invention〕

As explained above, according to the formwork covering material of the present invention, when air or excess water flows into the pinhole at the boundary with the concrete base material,
It penetrates the back side of the outer layer through the pinholes, into the base material, and into the contact surface with the concrete formwork, spreading both ways, and as a result, it is also absorbed into the concrete formwork over a wide area. It has the excellent effect of effectively preventing the formation of air bubbles and blisters, which are the cause of cavities on the surface of concrete.

[Brief explanation of the drawing]

Figures 1 to 4 illustrate a covering material according to an embodiment of the present invention. Figure 1 is a diagram explaining the relationship between the covering material and the formwork, and Figure 2 is a developed view of the covering material. , FIG. 3 is a partial cross-sectional view showing the structure of the covering material, and FIG. 4 is a partially enlarged cross-sectional view in a state of use. 1... Covering material, 4... Concrete formwork, 10
... Outer layer (waterproof layer), 11 ... Base material, 13 ... Through hole, 15 ... Pinhole.

Claims (1)

[Claims] 1 Formwork coating material that is removably applied to concrete formwork to improve its releasability from concrete, with an outer layer made of a water-resistant film, foil, sheet, etc., and a corrugated cardboard base paper on the back side of this outer layer. It is made by laminating water-absorbing base materials such as kraft paper, cardboard sheets, cardboard, water-absorbing fibrous materials, and water-absorbing polymer materials, and is formed by scattering countless pinholes that pass through both the outer layer and the base material. 1. A formwork covering material, characterized in that it is formed in a shape to removably cover the front side of the formwork except for the back side.