JPH03144064A - Form for placing concrete - Google Patents

Abstract

PURPOSE:To ensure quality of concrete by a method wherein a water retention layer is laminated directly on a concrete placed surface or through a cushion sheet, and a water permeable surface layer on which a concrete placed surface is formed is laminated on the water retention layer. CONSTITUTION:A water retention layer 2 formed of a water absorptive high molecular material is formed on the one surface of a form body 1, and further a surface layer 3 formed of a plastic film, e.g. polyethylene, having a number of fine through-holes is laminated on the layer 2. Concrete is placed adjacently to the surface layer 3, a moisture content produced from concrete is absorbed through the through-holes of the surface layer 3 and held at the water retention layer 2 and removed from a concrete placed surface. In a way that after curing of the concrete, the form body 1 is removed and the water retention layer 2 and the surface layer 3 are caused to remain, a wet state is kept by means of the absorbed and held moisture content. This constitution provides concrete of high quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of removing moisture generated from concrete during concrete pouring from a concrete pouring surface.
For this reason, the present invention relates to a concrete casting form that does not leave blisters on the concrete casting surface, and furthermore, can maintain the concrete casting surface in an appropriate moist state during curing of concrete and perform good moist curing.

[Conventional technology]

Traditionally, wooden plywood or iron formwork has been used to place concrete, but when concrete is poured using these formworks and allowed to harden, the surface of the concrete placed in contact with the formwork is However, there was a problem in that the moisture mixed in the concrete caused the remains of blisters and fine irregularities (so-called junks).

In order to solve this problem, recently, the formwork is equipped with many through-holes for moisture drainage, with the aim of actively draining the moisture present on the concrete pouring surface from the concrete pouring surface. Formwork designed to discharge excess moisture and air bubbles, or formwork with a water-permeable layer on the surface of the formwork, have been proposed. According to such formwork, excess water generated from concrete during pouring can be removed. Removes moisture from the pouring surface,
It is possible to prevent the generation of bubble marks.

[Problem to be solved by the invention]

When forming a concrete wall, etc., after the concrete is poured and hardened, the concrete is kept warm and the surface on which the concrete is poured is kept moist to prevent rapid drying and shrinkage of the concrete. Moist curing is performed to improve its strength,
When concrete is poured into the formwork mentioned above, after the concrete has hardened, there is no moisture content until the end of curing.
For this reason, after the concrete has hardened, the formwork is removed and the concrete is warmed by covering the concrete casting surface with a curing sheet base. Preventing rapid drying shrinkage? It is necessary to carry out U-curing, and therefore there is a problem in that curing requires a large amount of labor.

The present invention was developed in view of the above circumstances, and is capable of removing water deposits generated from concrete from the concrete pouring surface during concrete pouring, and without leaving any blisters on the concrete surface. An object of the present invention is to provide a concrete casting mold that can perform wet curing in a good and simple manner during curing of concrete.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a water-retaining material containing a water-absorbing polymer substance on the surface of the formwork body on the concrete placement side directly or through a water-conducting buffer sheet. To provide a formwork for concrete casting, characterized in that layers are laminated, and a water permeable surface layer forming a concrete pouring surface is further laminated on the water retaining layer.

Here, the water-absorbing polymer material that constitutes the water-retaining layer is as follows:
Vinyl acetate-acrylic acid copolymer system, starch-acrylic acid graft copolymer system, starch-acrylonitrile graft copolymer system, polyvinyl alcohol maleic anhydride system, inbutylene-maleic anhydride system, polyacrylic acid system, etc. They can be suitably used, and a water-retaining layer can be constructed by using these alone or by dispersing them in a nonwoven fabric or the like. In addition, the surface layer is not particularly limited, but plastics such as polyethylene and ethylene-vinyl acetate copolymer, which have a large number of micropores, and film may be used in terms of peelability from the concrete surface after the concrete has finished curing. Preferably used from Furthermore, when the water retaining layer is laminated via a buffer sheet, nonwoven fabric, woven fabric, synthetic resin net, synthetic resin corrugated sheet, etc. can be used as the buffer sheet. Note that as the formwork body, a material that is resistant to concrete casting pressure, specifically, an iron plate, a wooden board, a synthetic resin board, etc., is used.

[For production]

The formwork for placing concrete of the present invention is used to place concrete in contact with the surface layer of the formwork, but when concrete is placed, moisture generated from the concrete passes through the surface layer of the formwork and enters the water retention layer. It is absorbed and removed from the concrete pouring surface, and can prevent the formation of blisters and fine irregularities on the concrete pouring surface, so that the concrete surface can be placed cleanly. Also,
In this case, by laminating a water-retaining layer with a water-conducting buffer sheet interposed therebetween, or by forming a water-retaining layer with a water-absorbing polymer material dispersed in a nonwoven fabric, moisture exceeding the water absorption capacity of the water-absorbing polymer material may be generated. Even in such a case, this water can flow through the buffer sheet or the hand-woven cloth constituting the water-retaining layer and be discharged to the outside.

In addition, concrete is poured using the formwork of the present invention,
+' when curing concrete after it hardens
t. With the formwork attached to the concrete pouring surface, or by separating the formwork body and sheets and removing the formwork body, the top sheet and water retaining layer are left on the concrete pouring surface,
The water absorbed and retained by the water-absorbing polymeric substance in the water-retaining layer keeps the concrete pouring surface in a moderately moist state and also keeps the concrete pouring surface warm, making it easy and convenient for moist curing of concrete. can be done.

Furthermore, after the above-mentioned moist curing is completed, a surface layer exists between the water retaining layer and the concrete placement surface, so by using the above-mentioned water permeable plastic film with excellent releasability as this surface layer, the formwork or A sheet left on a concrete placement surface can be easily removed without damaging the concrete placement surface.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

Figure 1 shows a formwork for concrete pouring according to an embodiment of the present invention, in which one side of the formwork body 1 is made of a water-absorbing polymer material with a thickness of about 0.1 to 511 mm. , especially 0.3 to 1.
A water retaining layer of 5 wheels is formed, and a large number of microscopic holes (usually 0.1 to 1.51 mm in diameter, preferably 0.5 mm in diameter) are formed on this water retaining layer 2.
．． Polyethylene, ethylene-
A surface layer 3 made of a plastic film such as vinyl acetate copolymer is laminated thereon.

When concrete is poured using this formwork to form a concrete wall or the like, concrete is first poured in contact with the surface layer 3. As a result, water generated from the concrete passes through the pores of the surface layer 3, is absorbed and retained by the water-absorbing polymeric substance constituting the water-retaining layer 2, and is removed from the concrete placement surface.

Therefore, according to this formwork, water generated from concrete can be reliably removed from the concrete pouring surface, which prevents the formation of blisters and fine irregularities on the concrete pouring surface due to the presence of water bubbles. A smooth concrete pouring surface is created without any problems.

After the concrete has solidified, the entire formwork can be left attached to the concrete pouring surface, or the formwork body 1 and the water retaining layer 2 can be separated and the formwork body 1 can be removed from the concrete pouring surface. At the same time as removing it, by leaving the water retaining layer 2 and surface layer 3 on the concrete casting surface, the concrete casting surface is kept in a moderately moist state by the water absorbed and retained by the water absorbing polymeric substance that constitutes the water retaining layer 2. At the same time, the water retaining layer 2 and the surface layer 3 can keep the concrete warm. Therefore, good moisture curing can be performed without having to perform complicated operations such as placing a curing sheet on the concrete placement surface or constantly sprinkling water on the concrete placement surface.

Furthermore, after curing, a plastic film with excellent peelability is used as the surface layer that comes into contact with the concrete pouring surface, so it does not damage the concrete pouring surface.
The formwork or sheets can be easily removed.

In this way, with this formwork for concrete pouring, it is possible to pour concrete neatly without creating blisters or fine irregularities, and when curing concrete, it is possible to curing the concrete pouring surface again. There is no need to perform complicated work such as arranging sheets or constantly sprinkling water on the concrete pouring surface, and the work of forming concrete walls etc. can be simplified.

Fig. 2 shows a formwork for concrete pouring according to another embodiment of the present invention, in which one side of the formwork body 1 is covered with non-woven fabric, woven fabric, synthetic resin net, synthetic resin corrugated sheet, etc. A water-conducting buffer sheet 4 consisting of the following is laminated, and a water retaining layer 2 and a surface layer 3 similar to those of the first embodiment are sequentially laminated on this buffer sheet 4.

Similar to the formwork of the first embodiment, this formwork is also one in which concrete is placed in contact with the surface layer 3, so that water generated from the concrete is absorbed into the water-retaining layer 2 through the holes in the surface layer 3. - Moisture is removed from the concrete placement surface, but in this case, in this formwork, if an amount of moisture is generated from the concrete that exceeds the water absorption capacity of the water-absorbing polymer material that makes up the water-retaining layer 2. However, it is possible to guide this to the buffer sheet 4 and drain the excess moisture to the outside by flowing through the buffer sheet 4, thereby making it possible to more reliably form a smooth concrete pouring surface.

Furthermore, according to this formwork, when curing concrete,
Concrete is poured into the formwork body 1 with the formwork attached to the concrete pouring surface, or by separating the formwork body 1 and the buffer sheet 4 or between the buffer sheet 4 and the water retaining layer 2. At the same time as removing it from the surface, the sheet a containing the water retaining layer 2 can be left on the concrete casting surface, and the concrete can be wet-cured in the same manner as in the first embodiment.

Moreover, FIG. 3 shows still another embodiment of the concrete casting formwork of the present invention, in which the above-mentioned water-absorbing polymer substance is dispersed in a nonwoven fabric on one side of the formwork body 1. A water retaining layer 5 is laminated, and a surface layer 3 similar to that of the first embodiment is formed on top of this, and water generated from the concrete is dispersed into the water retaining layer 5 through the holes in the surface layer 3. At the same time, surplus water that cannot be absorbed flows through this water-retaining N5 nonwoven fabric and is discharged to the outside. , to keep the concrete pouring surface in a good moist condition. Note that the other effects of this formwork are the same as those of the first embodiment, so
The explanation will be omitted.

The formwork for concrete pouring of the present invention is not limited to the above-mentioned embodiments, and various changes may be made within the scope of the gist of the present invention.

As explained above, according to the formwork for concrete pouring of the present invention, water generated from concrete during concrete pouring is absorbed into the water retaining layer through the surface layer, thereby improving concrete pouring. Therefore, it is possible to reliably prevent the formation of blisters and fine irregularities on the concrete placement surface, and therefore the concrete surface can be placed cleanly. In addition, when curing concrete, the water absorbed and retained in the water retaining layer keeps the surface of the concrete placed in a moderately moist state, and
The water retaining layer 2 surface layer can keep the concrete warm,
Therefore, when curing concrete, there is no need to separately arrange a curing sheet or perform treatments such as sprinkling water, and the work of forming concrete walls etc. can be simplified.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing embodiments of the present invention, respectively. 1... Form body, 2, 5... Water retention layer, 3... Surface layer, 4... Buffer sheet

Claims (1)

[Claims] 1. A water retaining layer containing a water-absorbing polymer substance is laminated directly or via a water-conducting buffer sheet on the concrete pouring side of the formwork body, and a concrete pouring surface is further formed on the water retaining layer. A formwork for concrete pouring characterized by a laminated water-permeable surface layer.