JPH02130102A - Method for treating inner surface of concrete mold - Google Patents

Abstract

PURPOSE:To dispense with coating at each molding and to make the coating of oil sufficient at every molding of several times by forming a film composed of a synthetic resin hard to release from a steel plate and having good concrete releasability to the inner surface of a mold made of a steel plate for molding concrete and applying fatty acid to the film before casting concrete. CONSTITUTION:A sinthetic resin film 2 is formed to the steel plate 1 of a mold and a film 3 composed of fatty acid is formed thereon. Next, when a mold is filled with concrete C, aggregate 4 breaks the fatty acid film 3 at a part to slightly penetrate in the synthetic resin film 2. The fatty acid film 3 on the steel plate 1 of the mold becomes thin by the quantity transferred to the concrete C to be left on the steel plate 1 and an impression 5 is formed at the part where the aggregate 4 is pushed in. When the charging and demolding of concrete are repeated several times and the fatty acid film 3 becomes thin, fatty acid dissolved in a volatile solvent is applied by spraying. The solvent is volatilized for about 30min - 1hr after spraying to restore the thickness of the fatty acid film 3 before use. The impression 5 formed to the synthetic resin film 2 is left but there is no problem from a practical stand point.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for treating the inner surface of concrete formwork.

<Prior Art> The inner surface of a concrete formwork is treated to prevent the concrete filled into the formwork from adhering or remaining when the formwork is removed, and conventionally, only a release agent was applied. Recently, Utility Model Publication No. 58-4652, ``Formwork that does not require release agent,'' proposed an inner surface treatment that improves the peelability of concrete without applying a release agent.

The content is to create a porous structure layer on the inner surface of the mold using synthetic resin, powder, and granules, and to impregnate this layer with oil. The oil expands as the temperature rises during concrete curing, preventing concrete from sticking.

However, this idea has not been put into practical use because it has no practical effect. Theoretically, this seems to be because there is little oil on the surface of the formwork when concrete is poured, so it tends to stick to it, and even if the oil bulges out during curing, it is not possible to separate the entire surface of the concrete.

<Problem to be solved by the invention> In concrete product manufacturing factories, concrete is poured into steel forms, whether the mold is removed immediately using hardened concrete or cast with solid line concrete, once the product is removed from the mold. Before the first injection, the inner surface is always cleaned and oiled (release agent applied).

If cleaning is not done, it will create defects on the concrete left on the inside of the formwork or on the surface of the next product. If oil is not applied, some concrete will stick to the inner surface of the form, creating gaps on the surface of the product. Steel plate formwork tends to adhere to concrete, so -
After each concave molding, the mold is cleaned with a wire brush or the like to remove even the slightest concrete adhesion, and then the inner surface of the form is coated with oil using a blower or the like. As long as steel plate formwork was used, both cleaning and oiling were considered essential.

In this invention, the inner surface of the steel plate formwork is treated so that the above-mentioned cleaning is completely unnecessary and oiling only needs to be done every few times of concrete molding.

Means for Solving the Problems> The method for treating the inner surface of a concrete formwork of the present invention provides a method for treating the inner surface of a concrete formwork that is difficult to peel off from the steel plate, on the inner surface of a steel plate formwork for concrete forming.
A synthetic resin coating with good removability from concrete is formed before concrete is poured.

The method is characterized in that a fatty acid is further applied onto the above coating film.

Preferably, the synthetic resin coating is formed by a baking method, and the fatty acid is applied by spraying using a volatile solvent.

Furthermore, as a means to extend the life of the above-mentioned coating film.

It is preferable to weld, press, or adhere a thin film of hard powdery material to the inner surface of the mold to form a rough surface before forming the coating film.

Furthermore, the above-mentioned fatty acid is applied each time the product is demolded, and the amount of application is sufficient to compensate for the wrinkles that have been reduced because the fatty acid that has risen in temperature during curing penetrates into the concrete side and forms a waterproof film. preferable.

(Function) If you choose a synthetic resin paint that is difficult to peel off when painted on the steel plate and has good peelability from the concrete filled in it, such as polyphenylene sulfide, and form that coating on the inner surface of the formwork, the steel plate formwork will be removed. It provides complete rust prevention and perfect removability from hardened concrete. However, the paint film is so weak that if concrete containing gravel is repeatedly poured into it, it will rapidly wear away, exposing the steel plate.

As a means to prevent wear of this coating film, a fatty acid such as vaseline is applied to the coating film before concrete is poured. This fatty acid coating acts as a protective layer between the poured concrete and the coating on the formwork side, significantly reducing wear on the coating, and also acts as a release agent during demolding.

The fatty acid coating is transferred to the concrete side and diluted to some extent each time it is poured into concrete, so it is necessary to replenish it so that the bare surface of the synthetic resin coating does not come out, but it does not need to be done every time like traditional oil application good.

During curing after concrete is poured, the fatty acid coating on the heated inner surface of the mold gains fluidity and penetrates into the concrete to some extent, creating a waterproof coating on the demolded product.

As stated in claim (2), the easiest and most reliable way to carry out this invention is to apply a baking coating method to form a synthetic resin coating, and to apply a spray coating using a volatile solvent to apply a fatty acid coating.

Further, as described in claim (3), if hard powder and granule material is welded, crimped, or adhered in advance to the inner surface of the formwork in a thin film form, and the synthetic resin coating film is formed thereon, the hard powder and granule material The rough surface caused by the material is evenly covered with a coating film.

Even if the paint film in this state is directly subjected to friction by breaking the poured concrete or fatty acid coating, only the paint film on the convex parts of the hard rough surface will wear out, and the paint film on the convex parts will not wear out. Not many,
As a result, the coating film as a whole has minimal wear, and the inherent properties of the coating film, such as removability from concrete, are maintained for a long time.

As described in claim (4), if a fatty acid is supplementally applied each time, a waterproof film can be formed on the demolded product.

Embodiment Example Fig. 1 is a partial cross-sectional view of the inner surface of a steel plate form which has been subjected to the inner surface treatment of the present invention, in which 1 is a form steel plate, 2 is a synthetic resin coating film formed thereon, and 3 is a synthetic resin coating film formed thereon. It is a coating of fatty acid (Vaseline) applied to the surface.

Figure 2 shows concrete C filled with the inner surface of the formwork shown in Figure 1.
In some parts, the aggregate (gravel) 4 or the fatty acid coating 3 has been broken and the synthetic resin coating 2 has been bitten into the coating to some extent.

Figure 3 shows concrete C in Figure 2 starting to separate from the inner surface of the formwork due to demolding. On the surface of the concrete C, a thin fatty acid coating 3' is formed by the fatty acid 3 on the formwork side gaining fluidity due to the temperature increase during curing and partially penetrating into the surface of the concrete C. This has the effect of making the product surface waterproof. To create a sufficient waterproof film on the surface of the product, apply the necessary amount of extra fatty acid each time the product is demolded.

The fatty acid coating 3 of the formwork steel plate L becomes thinner and remains as it moves toward the concrete C side, and in the part where the aggregate 4 is pushed, it partially bites into the synthetic resin coating 2 and creates a pressure [5]. There is.

Figure 4 shows a state in which the fatty acid coating 3 has become thinner after repeating the above-mentioned concrete pouring and demolding several times, so a fatty acid dissolved in a volatile solvent (alcohol, etc.) is applied by spraying.
The solvent will evaporate in about 30 minutes to 1 hour after spraying.
The thickness of the fatty acid coating 3 before use shown in FIG. 1 is returned to. However, the impressions 5 made on the synthetic resin coating film 2 remain, but this poses no practical problem.

The practical life of the synthetic resin coating 2 comes to an end when the deep indentation 5 that reaches the steel plate 1 spreads and the peelability of the concrete can no longer be maintained.

In order to greatly increase the life of the synthetic resin coating 2, apply it to the steel plate l on the inner surface of the form! FIG. 5 shows a cross-sectional view of an embodiment in which hard powder material 6 is thinly welded as a pretreatment before baking 2 and painting.

It is made by heating the surface of the steel plate 1 with a gas burner and uniformly scattering ceramic grains as the hard powder material 6 thereon, but the powder material 6 may also be pressed and crimped with a roller or the like. Even without heating, you can apply adhesive to one steel plate, sprinkle powder material 6 on it, and press it lightly.
The method of attaching the powder material 6 to the steel plate 1 is arbitrary.

The embodiment shown in FIG. 5 is a cross-sectional view of a structure in which a powder material 6 is thinly adhered to a steel plate 1, the aforementioned synthetic resin coating 2 is baked or painted, and a fatty acid coating 3 is sprayed on top of it. be.

Fig. 6 shows a state in which the synthetic resin coating 2 of Fig. 5 maintains its removability from concrete even if it is greatly worn due to repeated pouring and demolding of concrete during long-term rIF1. The coating [2], which was up to a height of 2゛, has been heavily worn away due to the friction and impact of the concrete aggregate that has broken through the fatty acid coating 3. However, as shown in the coating film 2 shown by the solid line in FIG. 6, the coating film 2 in the concave portions of the uneven surface formed by the powder material 6 goes behind the convex portions and is not subjected to friction or blows, making it difficult to maintain removability. Sufficient coating area is maintained. Coating Wi on the convex part
The components are greatly worn due to friction and impact, and the upper end of the powder granule material 6 is often exposed, but this is due to the wide coating.
! ! They are only scattered in spots on the surface of 2, and are covered by the fatty acid coating 3, which is omitted in Figure 6, so concrete is attached there! 1# Does not generate adhesion that reduces properties.

The formwork 7 whose cross section is shown in Fig. 7 is used to form a concrete U-shaped groove C'.
Open 7a to the left and right to the chain line position and demold the product upward. After that, the entire inner surface of the formwork is cleaned with a single rotating brush, or the rotary brush that is automatically operated only on the narrow refractive surface 8 at the north end of both side plates 7a is difficult to clean.

Therefore, after applying the inner surface treatment method of the present invention only to the vicinity of the refractive surface 8, when manufacturing the mold 7, the vicinity of the refractive surface 8 was sandblasted, and a commercially available thermoplastic resin with excellent peeling properties was used. If the refractive surface 8 is baked and coated with polyphenylene sulfide and sprayed to an extent that the fatty acid will not be depleted during use, and the other parts are oiled each time as before, cleaning the refractive surface 8 will be completely unnecessary.

Before the baking process, a sandblasted steel plate is heated with a burner to attach ceramic grains as shown in Figure 5, so that it can be used semi-permanently without cleaning.

Although the present invention has been described in detail above, the present invention will be described depending on the implementation conditions without changing the gist thereof.

It goes without saying that it can be varied and applied in a variety of ways through the well-known techniques and ingenuity of engineers.

<Effects of the invention> This invention breaks the conventional fixed concept that cleaning and oiling work is indispensable every time steel plate formwork is prone to rust and has poor concrete peelability, and completely eliminates the need for cleaning work for the first time. We were able to provide a method for treating the inner surface of formwork.

That is, the present invention covers the surface of the steel plate with a synthetic resin coating to prevent contact between the formwork steel plate and concrete, and protects this easily abraded coating by covering it with a fatty acid coating that is a viscous solid. The fatty acid also acts as a release agent during demolding.

By combining a weak synthetic resin coating with a fatty acid coating that is occasionally replenished, there is no concrete adhesion or residue even on steel plate formwork, completely eliminating the need for cleaning after product demolding.

And since the fatty acid does not form a thin film like the conventional oil-based release agent coated surface and does not run down, it can withstand several times of concrete pouring and demolding, and the conventional oiling work is significantly reduced.

The inner surface treatment method of the present invention can be carried out very easily by forming a synthetic resin coating by the well-known baking method and then spraying a fatty acid diluted with a volatile solvent.

In addition, by applying a thin layer of hard powder to the base of the synthetic resin coating, the drawbacks of the coating, which tend to wear easily, have been significantly improved.

Also, each time, the fatty acid sprayed onto the inside of the formwork penetrates into the concrete at the curing temperature, creating a waterproof film on the surface of the product.

This invention also has a great technical effect of promoting the rationalization of cleaning and oiling operations for steel plate formwork, which have not been advanced in the past.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of the inner surface of a form to which this invention is applied, Fig. 2 is a sectional view of the form filled with concrete,
Fig. 3 is a cross-sectional view of the concrete starting to separate from the inner surface of the form due to demolding, and Fig. 4 is a cross-sectional view of the inner surface of the form after it has been used and has been restored by spraying and replenishing fatty acid.
Figure 5 is a partial sectional view of the inner surface of the formwork when a thin layer of hard powder material is attached as a pretreatment to the base of the synthetic resin coating, and Figure 6 is a sectional view showing the state of wear of the formwork shown in Figure 5. . FIG. 7 is an explanatory cross-sectional view of a formwork to which this invention is locally applied, in which 2 is a synthetic resin coating, 3 is a fatty acid coating,
6 indicates a hard powder material.

Claims (4)

[Claims] (1) A synthetic resin coating that is difficult to peel off from the steel plate and has good concrete releasability is formed on the inner surface of the steel plate formwork for concrete molding, and a fatty acid is further applied on top of the coating before concrete is poured. A method for treating the inner surface of concrete formwork. (2) In the method for treating the inner surface of concrete formwork according to claim (1), the synthetic resin coating is formed by a baking coating method, and the fatty acid is applied by spraying using a volatile solvent. A method for treating the inner surface of concrete formwork. (3) In the method for treating the inner surface of a concrete formwork according to claim (1), before forming the coating film, a thin layer of hard granular material is welded, crimped, or adhered to the inner surface of the formwork, A method for treating the inner surface of concrete formwork, which is characterized by creating a rough surface. (4) In the method for treating the inner surface of concrete formwork according to claim (1) or (3), the application of the fatty acid is performed each time the product is demolded, and the amount of application is such that the fatty acid heated during curing is A method for treating the inner surface of concrete formwork, which is characterized by penetrating into the concrete side and creating a waterproof membrane, so that the amount is sufficient to compensate for the amount lost.