JP2964501B2 - Concrete casting formwork - Google Patents

Description

[Detailed Description of the Invention] [Industrial application field] The present invention can remove moisture generated from concrete during concrete casting from a concrete casting surface, so that water mark remains on the concrete casting surface. The present invention also relates to a concrete casting formwork capable of maintaining the concrete casting surface in an appropriate wet state during curing of the concrete and performing good wet curing.

[Conventional technology]

Conventionally, in concrete casting, wooden plywood and iron formwork have been used.However, when concrete is cast using these forms and solidified, the concrete casting surface in contact with the formwork is However, there is a problem that traces of water bubbles generated by water mixed in concrete are left behind, and fine irregularities (so-called "junka") are generated.

In order to solve such a problem, recently, in order to positively discharge moisture existing on the concrete casting surface from the concrete casting surface, a large number of through holes for discharging moisture are formed in the formwork, and extra A mold that discharges excessive moisture and air bubbles or a mold that has a water-permeable layer provided on the surface of the mold has been proposed. According to such a mold, an excess amount of concrete generated during casting is produced. It is possible to remove moisture from the casting surface and prevent the occurrence of air bubble marks.

[Problems to be solved by the invention]

Here, when forming a concrete wall or the like, after the concrete is poured and solidified, the concrete is kept warm while the concrete casting surface is kept in a wet state to prevent rapid drying shrinkage of the concrete while the concrete is poured. Moisture curing is performed to improve the strength, but when concrete is poured using the formwork, after the concrete solidifies, it is not possible to maintain a good wet state until curing is completed. Therefore, after the concrete solidifies, remove the formwork, cover the concrete casting surface with a curing sheet, etc., and keep the concrete warm,
It is necessary to constantly sprinkle water on the concrete casting surface to prevent rapid drying and shrinkage of the concrete and to perform wet curing, and thus there is a problem that a large amount of labor is required for curing.

The present invention has been made in view of the above circumstances, and it is possible to remove moisture generated from concrete at the time of casting concrete from the casting surface, so that no water bubbles are left on the concrete surface, and furthermore, when the concrete is cured. An object of the present invention is to provide a concrete casting formwork capable of performing wet curing in a good and simple manner.

[Means for solving the problem]

In order to achieve the above object, the present invention has a water retaining layer containing a water-absorbing polymer substance laminated directly or via a water-conducting buffer sheet on the surface of the formwork body on the concrete casting side, and further comprising the water retaining layer. Provided is a concrete casting formwork characterized by laminating a water-permeable surface layer made of a plastic film of polyethylene or ethylene-vinyl acetate copolymer having a large number of fine holes forming a concrete casting surface thereon. I do.

Here, as the water-absorbing polymer material constituting the water retaining layer, vinyl acetate-acrylic acid copolymer, starch-acrylic acid graft copolymer, starch-acrylonitrile graft copolymer, polyvinyl alcohol maleic anhydride, Inbutylene-maleic anhydride-based, polyacrylic-acid-based materials and the like can be suitably used, and these can be used alone or by dispersing them in a nonwoven fabric or the like to form a water retention layer. As the surface layer, a polyethylene or ethylene-vinyl acetate copolymer plastic film having a large number of fine pores is used from the viewpoint of the releasability from the concrete surface after the concrete curing is completed. Further, when the water retention layer is laminated via a buffer sheet, a nonwoven fabric, a woven fabric, a synthetic resin net, a synthetic resin corrugated sheet, or the like can be used as the buffer sheet. In addition, as the formwork body, one having resistance to the concrete casting pressure, specifically, an iron plate,
A wood board, a synthetic resin board, or the like is used.

(Operation)

The concrete casting formwork of the present invention casts concrete in contact with the surface layer, but when casting concrete, moisture generated from the concrete passes through the surface layer of the formwork to the water retaining layer. Absorbed and removed from the concrete casting surface, the formation of water bubbles and fine irregularities on the concrete casting surface can be prevented, so that the concrete surface can be cast neatly. Further, in this case, by laminating the water-retaining layer via a buffer sheet having water conductivity, or by forming a water-retaining layer in which a water-absorbing polymer is dispersed in a nonwoven fabric, the water-absorbing capacity of the water-absorbing polymer is exceeded. When this occurs, the water can flow through the nonwoven fabric constituting the buffer sheet or the water retaining layer and be discharged to the outside.

When the concrete is cast using the formwork of the present invention and the concrete is cured and then cured, if the formwork is still attached to the casting surface, or the formwork body and sheets and the like And remove the formwork body, leaving the surface sheet and the water retention layer on the concrete casting surface,
The water absorbed by the water-absorbing polymer material in the water-retaining layer keeps the concrete-casting surface in a moderately wet state and also keeps the concrete-casting surface warm, so that the concrete can be wet-cured easily and easily. Can be performed.

Furthermore, after the completion of the above-mentioned wet curing, there is a surface layer between the water retaining layer and the concrete casting surface. Therefore, by using the above-described water-permeable plastic film having excellent releasability as the surface layer, the formwork or concrete can be formed. The sheet can be easily removed by leaving the sheet on the casting surface without damaging the concrete casting surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

〔Example〕

First Embodiment FIG. 1 shows a concrete casting mold according to an embodiment of the present invention. One surface of the mold body 1 is made of a water-absorbing polymer material and has a thickness of about 0.1 to 5 mm. A water-retaining layer having a thickness of 0.3 to 1.5 mm is formed, and a polyethylene, ethylene-vinyl acetate copolymer, or the like having a large number of fine pores (normally 0.1 to 1.5 mm, preferably 0.3 to 0.8 mm) on the water retaining layer 2 The surface layer 3 made of a plastic film is laminated.

When concrete is cast using this formwork to form a concrete wall or the like, concrete is first cast in contact with the surface layer 3. As a result, the water generated from the concrete is absorbed and held by the water-absorbing polymer material constituting the water-retaining layer 2 through the through-holes of the surface layer 3, and is removed from the concrete-casting surface. Therefore, according to this formwork, the moisture generated from concrete can be reliably removed from the concrete casting surface, so that the water mark and fine irregularities caused by the presence of moisture bubbles on the concrete casting surface are generated. And a smooth concrete casting surface is formed.

After the concrete has solidified, the entire formwork may be left attached to the casting surface, or the formwork body 1 and the water retaining layer 2 may be attached.
To separate the form body 1 from the concrete casting surface and leave the water retaining layer 2 and the surface layer 3 on the concrete casting surface, thereby forming the water absorbing polymer constituting the water retaining layer 2. The concrete pouring surface can be kept in an appropriate wet state by the moisture absorbed and retained in the substance, and the concrete can be better kept warm by the water retaining layer 2 and the surface layer 3. Therefore, good wet curing can be performed without performing a complicated operation such as disposing a curing sheet on the concrete casting surface or constantly spraying water on the concrete casting surface.

Furthermore, after curing, since a plastic film having excellent releasability is used as a surface layer in contact with the concrete casting surface, the formwork or sheets can be easily removed without damaging the concrete casting surface. Things.

Thus, according to this concrete casting formwork,
The concrete can be cast neatly without causing water bubble marks and fine irregularities.When curing the concrete, arrange the curing sheet again on the concrete casting surface or always spray water on the concrete casting surface. It is not necessary to perform a complicated operation such as performing the operation, and the operation of forming a concrete wall or the like can be simplified.

Second Embodiment FIG. 2 shows a concrete casting mold according to another embodiment of the present invention, in which a nonwoven fabric, a woven fabric, a synthetic resin net, a synthetic resin corrugated sheet, etc. are provided on one surface of the mold body 1. A water-conducting buffer sheet 4 is laminated on the buffer sheet 4, and a water retention layer 2 and a surface layer 3 similar to those in the first embodiment are sequentially laminated on the buffer sheet 4.

This mold also casts concrete in contact with the surface layer 3 in the same manner as the mold of the first embodiment, whereby water generated from concrete is absorbed by the water retaining layer 2 through the through holes of the surface layer 3. Is used to remove water from the concrete casting surface. In this case, in this case, if the amount of water generated from the concrete exceeds the water absorbing capacity of the water-absorbing polymer material constituting the water-retaining layer 2, However, this can be guided to the buffer sheet 4, and the excess water can be discharged to the outside by flowing through the buffer sheet 4, so that a smooth concrete casting surface can be more reliably formed.

Furthermore, according to this formwork, at the time of curing of the concrete, while this formwork is attached to the concrete casting surface,
Alternatively, the mold body 1 is removed from the concrete casting surface by separating both between the form body 1 and the buffer sheet 4 or between the buffer sheet 4 and the water retaining layer 2, and sheets including the water retaining layer 2 are removed. The concrete can be wet-cured by remaining on the concrete casting surface in the same manner as in the first embodiment.

FIG. 3 shows still another embodiment of the concrete casting mold according to the present invention. This mold is formed by dispersing the above-mentioned water-absorbing polymer material in a non-woven fabric on one surface of the mold body 1. A water retention layer 5 is laminated, and a surface layer 3 similar to that of the first embodiment is formed thereon. Water generated from concrete is dispersed in the water retention layer 5 through the through holes of the surface layer 3. The excess water that is absorbed and held by the water-absorbing polymer material and that cannot be absorbed flows through the non-woven fabric of the water-retaining layer 5 and is discharged to the outside. Thereby, the concrete casting surface is maintained in a favorable wet state. The other functions and effects of this formwork are the same as those of the first embodiment, and the description thereof will be omitted.

The concrete casting formwork of the present invention is not limited to the above-described embodiment, and may be variously modified within the scope of the present invention.

Effect of the Invention As described above, according to the concrete casting formwork of the present invention, water generated from concrete during concrete placement is removed from the concrete placement surface by absorbing the water generated through the surface layer into the water retaining layer. Therefore, it is possible to reliably prevent the formation of water marks and fine irregularities on the concrete casting surface, and thus it is possible to cast the concrete surface neatly. In addition, during the curing of concrete, the concrete pouring surface can be kept in an appropriate wet state by the moisture absorbed and retained in the water retaining layer, and the concrete can be kept warm by the water retaining layer and the surface layer. There is no need to provide a curing sheet or perform a process such as watering, so that the work of forming a concrete wall or the like can be simplified.

[Brief description of the drawings]

1 to 3 are cross-sectional views each showing an embodiment of the present invention. 1 ... form body, 2,5 ... water retention layer, 3 ... surface layer, 4 ...
… Buffer sheet

Claims (1)

(57) [Claims] 1. A water-retaining layer containing a water-absorbing polymer substance is laminated directly or via a buffer sheet having water-conductivity on a surface of the formwork body on a concrete-casting side. A concrete casting formwork characterized by laminating a water-permeable surface layer made of a plastic film of polyethylene or ethylene-vinyl acetate copolymer having a large number of fine pores forming the following.