JPH0353905A - Throw-away frame made of concrete - Google Patents

Abstract

PURPOSE:To raise adhesion of the contact surfaces between cast-in-place concrete and mold frames, and render both integrated by making the adhesive surfaces of concrete mold frames to cast-in-place concrete be treating surfaces, and roughened. CONSTITUTION:Throw-away frames are formed into a approximate rectangle so that a vertical frame 1a in the rear position and a slant frame 1b in the front position are stood previously on a bottom board 5 at an appropriate interval upon placing cast-in-place concrete 3. In washing out the concrete on their surfaces, aggregates in the concrete are exposed whereby the surfaces are roughened; as a result, the cast-in-place concrete is improved in its adhesion. When the concrete 3 is placed between the treating surfaces 2 of the throw-away frames which are washed out and removed away in this manner, it becomes a strengthened member such that the throw-away frames integrate with the concrete 3.

Description

[Detailed description of the invention] Industrial application field> The present invention relates to concrete disposable formwork used for construction of cast-in-place concrete structures such as retaining walls, and relates to disposable formwork and cast concrete. Improves the adhesion of both
Easier concrete work by integrating
1.
”.

<Prior art> Concrete disposable formwork is made by erecting vertical formwork at the back and inclined formwork at the front with appropriate spacing on the bottom slab before placing concrete on site, and reinforcing is arranged inside the formwork. It is used to pour ready-mixed concrete into the interior space. Using disposable formwork eliminates the process of disassembling the formwork, cleaning it, and applying a release agent, which is required when using wooden or steel formwork, and cement can be poured just by assembling the formwork. The construction period can be significantly shortened. Additionally, the surface is made of precast concrete, so it is aesthetically pleasing. It has become increasingly popular in recent years because it has many characteristics such as being left on the site without being collected even after concrete hardens, making it a strong member. However, the inner surface of the conventional concrete disposable formwork used for such construction was smooth.

<Problems to be Solved by the Invention> Therefore, early concrete disposable formwork was dangerous because it had a high possibility of peeling off due to adhesion to cast-in-place concrete. There are two representative examples of inventions that are said to have solved this problem. First, in 1986
- No. 53838, a plurality of protrusions whose tips are wider than their bases are formed on the inner surface that comes into contact with the filling concrete. Also, in Utility Model Application No. 61-54024,
The total amount of reinforcing bars required are assembled into concrete construction components, and these components are assembled as formwork and simultaneously integrated with cast-in-place concrete to form construction components. but,
These ideas had many problems. In the former case, the problems include the large amount of cement used, the inability to properly shape the large number of ridges unless the particle size of the aggregate is made small, and the cost of molds for manufacturing high. The latter method has problems such as not being easy to manufacture, being heavy and inconvenient to carry, and not being able to completely pour cement 1 between the reinforcing bars and the formwork.

The present inventor has solved many of the difficulties that these conventional concrete disposable formworks had.

<Means for solving the problem> As a result of considering the above-mentioned difficulties, the inventor of the present invention solved the problem by identifying the surface of the concrete mold that adheres to cast-in-place concrete and using it as the processed surface (2). ; The washed-out surface here refers to an uneven surface that is created by washing away the concrete before it solidifies, exposing the aggregate in the concrete and creating an uneven surface.

The unevenness further includes a partially exposed portion of the pipe material (7) or a partially exposed portion of the reinforcing bar (6).

<Function> When a polished surface (2) is provided on the surface of the concrete formwork that adheres to the cast-in-place concrete, the unevenness increases the adhesion to the cast-in-place concrete. Furthermore, it is possible to form a large number of protrusions or to provide exposed reinforcing bars on the inner surface of the sacrificial form by washing out after molding with a simple ordinary hollow form.

These irregularities or partially exposed portions of the reinforcing bars have the effect of increasing adhesion and bonding force, making the disposable formwork a strength member, and providing the integral strength of both the disposable formwork and the cast-in-place concrete.

<Example> -4- Fig. 1 is a perspective view showing the construction state of the concrete disposable formwork of the present invention. When placing cast-in-place concrete (3), the disposable formwork (1) is placed on the bottom slab (5) with an appropriate distance between the vertical formwork (1a) at the back and the inclined formwork (1b) at the front. It is formed into an almost rectangular shape so that it can stand upright.

The back side of the front inclined formwork can be seen in Figure 1, and in the present invention, the surface of the formwork concrete is removed by washing out and machining. For washing, the general washing process used for decorative concrete 1-blocks used for normal wall surfaces and bill calculations can be used, and water is sprayed using water pressure to a depth of about 5+ nm from the back side at the deepest point. It is done. In other words, the washing process referred to here is an application of the surface finishing method for walls or columns, and as shown in Figure 4, quartz, feldspar, etc.
Crushed stone aggregate is mixed in place of decorative stone pieces of about 200 m in diameter, poured into a forming mold to form a thinner inner layer than usual, and then ordinary mortar is poured to form it. If the mortar (8) on the surface is washed off when the mortar on the inner layer begins to harden, an uneven surface will be created. By washing off the concrete 1- on the surface in this way, the aggregate in the concrete is exposed and the surface is made uneven. This is intended to increase the adhesion with cast-in-place concrete 1-. When concrete (3) is placed between the machined surfaces (2) (2) of the sacrificial formwork that have been washed out and removed as shown in Figure 2, the sacrificial formwork (1) becomes the actual material. The poured concrete (3) is integrated to form a strong member.

As shown in Figure 3, if reinforcement (4) is placed and concrete is poured into this, it will become even stronger. In this case, the problem of rust on the inner surface of the disposable formwork remains, but if the ore reinforcement (6) is also placed inside the disposable formwork and a part of it is exposed by washing out, it can be connected to the reinforcement (4) with wire. Further integration is then achieved.

<Effects of the Invention> According to the present invention, the adhesive strength of the contact surfaces between the cast-in-place concrete and the formwork is increased by washing, and the two can be integrated. As a result, the concrete 1 and formwork can be calculated as an integral part of the concrete structure itself, making it possible to rationalize the use of materials, and making it possible to ensure accurate and easy reinforcing bar cover, leading to improved quality, etc. The effect was obtained.

[Brief explanation of drawings]

The construction drawing is a perspective view showing the construction state of the concrete disposable formwork of the present invention. FIG. 2 is a sectional view of the formwork from which the concrete surface has been removed by washing. FIG. 3 is a partial sectional view showing reinforcement between the washed and removed formwork. FIG. 4 is a cross-sectional view of a main part showing how an inner layer with a low hardening dimension is formed during manufacturing of the product of the present invention. (1) Concrete disposable formwork (1a) Vertical formwork (1b) Slanted formwork (2)
Cleaned surface (3) Cast-in-place concrete (4) Reinforcement (5) Bottom slab (6) #C in disposable formwork
(7) More than aggregate

Claims (1)

[Scope of Claims] 1. A disposable concrete formwork, characterized in that the surface of the concrete formwork that adheres to cast-in-place concrete is washed out and made into a processed surface (2) with irregularities. 2. The concrete disposable formwork according to claim 1, wherein the unevenness is a partially exposed portion of the aggregate (7) or a partially exposed portion of the reinforcing bar (6).