JPH02144472A - Concrete form - Google Patents

Abstract

PURPOSE:To obtain a form capable of curing while securing water necessary for hardening by providing a metal plate having a large number of narrow through-holes provided with a catch drain smaller than fine aggregate but bigger than cement particle to the inside of the form. CONSTITUTION:A metal plate 2 is mounted to the contact surface of a form body 1 and concrete 5. After that, a large number of narrow through-holes 3 is provided to the metal plate 2 smaller than fine aggregate 6 but bigger than cement particle and, at the same time, the rear is continuously connected to a catch drain 4. The surplus water and bubbles are such that they can be easily removed. According to the constitution, a concrete construction with high strength and high quality can be obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a formwork for concrete, and in particular to a formwork for concrete that is capable of simultaneously improving the surface condition of poured concrete after hardening and its curing condition. Concerning formwork.

(Prior Art) As is well known, excessive water is added to concrete poured when constructing concrete structures to ensure workability.

This excessively added water is removed when concrete is poured into the formwork due to the difference in specific gravity between cement, aggregate and water.

However, the water separated after pouring collects on the formwork surface with air bubbles, which causes so-called avatars to occur on the hardened concrete surface.

Concrete structures with such avatars not only lose their aesthetic appearance but also cause cracks.

In addition, excess water that collects at the interface between the poured concrete and the formwork increases the water-cement ratio of the concrete in this area, reducing the durability of the concrete after hardening and accelerating deterioration due to salt damage, etc. .

Therefore, as a method to solve this kind of problem, for example, Japanese Patent Application Laid-Open No. 60-43582, 1987 Concrete Engineering Annual Papers 91 ([1054] As disclosed in the Physical Properties Improvement Method, a method has been proposed in which a water-permeable or water-absorbing sheet is attached to the surface of the formwork that the concrete to be poured comes into contact with, and these sheets can remove separated water. Alternatively, by absorbing water, the above-mentioned problems can be solved.

In other words, in the former method, a sheet made of porous material is attached to the inside of the formwork, and excess water is actively drained through the sheet from the time the concrete is poured to the time it hardens, thereby reducing the amount of concrete at the interface. This is an attempt to prevent deterioration.

In the latter method, a sheet made of fiber material impregnated with a superabsorbent polymer is pasted on the inside of the formwork, and excess water from poured concrete is absorbed by the superabsorbent polymer to remove avatars. be.

(Problems to be Solved by the Invention) However, these construction methods have the following problems.

First, with the former, if a sheet of porous material is left in contact with concrete for a long period of time, cement particles in the concrete will enter the porous areas and harden, making the sheet extremely difficult to remove after curing. Ta.

On the other hand, if the sheet was removed early before curing was completed, there was a problem that the concrete could not be cured sufficiently.

In other words, when curing concrete, maintaining a moderately moist state has greater strength than curing in air.
If the sheet is removed early, the curing period in the air will be longer and the concrete will not be able to develop sufficient strength. In addition, this type of sheet has a large degree of opening and continuously removes moisture, so even if it is left in contact with a concrete surface for a long period of time, it is difficult to cure it in an appropriately moist state.

On the other hand, according to the latter, which uses a super absorbent polymer,
In reality, the surplus water was not absorbed as much as expected, and the absorbed polymer gelled and closed the voids in the fiber material, so the surplus water was not sufficiently drained, and the concrete strength was not sufficiently developed as described above. There was a problem that I couldn't do it.

This invention was developed in view of the above-mentioned problems, and is capable of curing in a wet state while securing the moisture necessary for hardening concrete without using a water-permeable sheet.
Another object of the present invention is to provide a formwork for concrete that can be easily demolded after concrete has hardened and that can be used more frequently.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a structure in which the concrete contact surface side and the external side of the formwork are smaller than the average grain size of fine aggregate and smaller than the maximum grain size of cement. It has a structure in which it communicates with many large pores.

Further, in this invention, the formwork is constituted by a formwork body and a metal plate that is removably laminated and adhered to the concrete contacting surface side of the formwork body, and the fine bones are formed by penetrating the inside and outside of the metal plate. A large number of pores smaller than the average particle size of the material and larger than the maximum particle size of the cement can be formed, and grooves communicating between the pores can be carved on the back surface of the metal plate.

(Function) According to the concrete formwork with the above configuration, the pores formed in the formwork are blocked by the aggregate in the concrete, but lateral pressure is applied to the formwork due to the weight of the poured concrete. This pressure causes excess water to weave through the gaps in the aggregate and drain to the outside through the pores.

As the poured concrete gradually hardens and the lateral pressure against the formwork decreases, the pores are blocked by aggregate, so
Drainage is reduced accordingly, ensuring the moisture needed for concrete hardening. At the same time, contact with air is cut off, allowing curing to take place in a moist state.

When the formwork is composed of a formwork body and a metal plate, excess water reaches the back side through the pores formed in the metal plate, and is discharged to the outside through the grooves that communicate between the pores, producing the same effect as described above. conduct.

The metal plate is smooth and can be easily removed even after the concrete has sufficiently hardened. After removal, it can be washed with water and reused. It can also be used as the formwork body and the metal plate.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

1 to 5 show a formwork according to the invention.

This formwork consists of a panel-shaped metal form 1 constituting the formwork body, and a metal plate 2 that is removably attached to the inner surface of the metal form 1.

The metal form 1 is a lightweight metal plate containing air bubbles formed to a predetermined thickness and size as a formwork material that can be used in place of the water-resistant plywood board conventionally used as a formwork.

The metal plate 2 is a metal plate with a thickness of 1,011 mm or more, in which pores 3 are regularly formed at 5 to 20 pitches, and the pores 3 have a diameter of 0 on the side of the contact surface with concrete.
．． It is 5 to 0.6 degrees, and it expands from here to 0.8 to 2 degrees on the back side, that is, the side in contact with the metal form 1.
It has the diameter of an irises.

In other words, the diameter of pore 3 on the concrete side is set to the above value, which is smaller than the average particle size of the fine aggregate used in the concrete to be poured, and larger than the maximum particle size of cement. Because I did. Further, the reason why the diameter of the rear side of the pores 3 is made large is to prevent clogging as much as possible.

Furthermore, as shown in FIG. 2, on the back side of the metal plate 2, a large number of grooves 4 are carved in a network shape to communicate between the pores 3, and the grooves 4 form a drainage path. It consists of

The width of this groove is 1.0~2.0cm, the depth is 0.5~0.8
m2, and the water and air bubbles discharged through the pores 3 are discharged to the outside of the formwork through these. The cross-sectional shape of the groove 4 can adopt various cross-sectional shapes such as a rectangular shape, a V-shape, and a semicircular shape as shown in FIGS. 3(a) to (c). It is fine as long as it satisfies the above requirements and has a shape that is easy to clean.

In addition, in processing the holes 3 and carving the grooves 4, means such as punching and laser processing, and combinations thereof, are used, for example.

Folded portions 2a with spring properties are formed on both sides of the metal plate 2 described above, and by fitting the folded portions 2a into both sides of the metal form 1, the metal form 1 is supported by the spring, and the - formwork is set. ting is now complete.

Depending on the shape of the intended concrete structure, a plurality of the above-mentioned formworks can be assembled by joining them vertically and horizontally, for example, as shown in FIG. 4, with the metal plate 2 inside.

Note that a release agent or the like is applied to the surface of the metal plate 2 as necessary. If the surface is treated in this manner, the metal plate 2 will be more easily peeled off from the surface of the concrete after curing.

When concrete 5 is placed inside the assembled formwork, it is compacted by its gravity and by a vibrator.

By placing the concrete 5, the pores 3 will be clogged relatively quickly by the aggregate 6 in the concrete 5, but the placed concrete 5 has its own weight,
This acts as lateral pressure against the formwork.

Then, due to this pressure, excess water or air bubbles weave through the gap between the aggregate 6 and the metal plate 2 as shown by the arrow in FIG. 1 and the edge of metal plate 2 to the outside.

When the poured concrete 5 gradually hardens and the lateral pressure against the formwork decreases, the pores 3 of the metal plate 2 are blocked by the aggregate 6, so the drainage also decreases accordingly.
Moisture necessary for hardening the concrete 5 is secured. Moreover, at the same time, contact with air is blocked by the metal plate 2 itself, and curing can be performed in a wet state.

After curing is completed, the formwork will be taken apart.

Since the metal plate 2 is smooth, it can be easily peeled off even after the concrete 5 has sufficiently hardened.

After peeling off, remove the metal plate 2 from the metal form 1 and wash the metal plate 2 with water to remove concrete residue adhering to the surface and concrete residue solidified in the pores 3 and grooves 4. This allows the metal plate 2 to be reused.

In the above embodiment, a metal form was used as the form body, but it goes without saying that commonly used water-resistant plywood or FRP plates may be used. Further, in the embodiments, the combination of the formwork body and the metal plate has been described, but in the present invention, the same effect can be obtained even if the above-mentioned pores are formed in the formwork itself.

(Effects of the Invention) As described above in detail through the embodiments, in the concrete formwork according to the present invention, excess water and air bubbles are removed from the pores, and after removal of the excess water and air bubbles, Since curing can be performed in a wet state, it is possible to obtain a high-strength, high-quality concrete structure.

Furthermore, when the formwork is a combination of the formwork body and metal plate, the metal plate that has peeled off from the concrete structure can be used repeatedly by cleaning, and can be reused instead of being disposable compared to conventional water-permeable sheets. There are other effects.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the concrete formwork according to the present invention, Fig. 2 is a perspective view showing a part of the back side of the metal plate, and Figs. A cross-sectional view showing an example of the cross-sectional shape, FIG. 4 is an explanatory view showing a state in which concrete is placed inside the formwork, and FIG. 5 is an explanatory view showing a state in which excess water is drained. 1... Metal form (formwork body) 2...
...Metal plate 3...Small hole 5...Concrete 4...Groove 6...Aggregate

Claims (2)

[Claims] (1) A concrete mold characterized in that the concrete contact surface side of the formwork and the outside side are communicated with each other through a large number of pores that are smaller than the average grain size of fine aggregate and larger than the maximum grain size of cement. frame. (2) The formwork consists of a formwork body and a metal plate that is removably laminated and adhered to the concrete contact side of the formwork body, and the metal plate has an average particle size of fine aggregate that penetrates the inside and outside of the metal plate. 1. A large number of pores smaller than the cement diameter and larger than the maximum particle diameter of the cement are formed, and grooves are carved on the back surface of the metal plate to communicate between the pores. Formwork for concrete as described in .