JP2861783B2 - Formwork for concrete casting and sheet for attaching formwork - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete casting formwork and a sheet for applying the formwork to be attached to a surface of the formwork which comes into contact with concrete.

[0002]

2. Description of the Related Art Conventionally, regarding improvement of physical properties of a concrete form surface, a water-permeable or water-absorbing sheet is attached to a form surface in contact with concrete, thereby facilitating removal of the form from the form. It has been proposed to finish the surface of concrete precisely and beautifully.

For example, in Japanese Patent Application Laid-Open No. 63-55264, as shown in FIG.
4 is bonded to one surface of a nonwoven fabric release surface material (polyethylene, polypropylene, polyester, cotton, or the like) 25 having water permeability and air permeability to form the open-celled rigid urethane foam plate 23. By this pasting process,
The cement solid content can be prevented from flowing out together with the breathing water, and the contact surface between the concrete 26 and the urethane plate 24 becomes smooth, so that the urethane plate form after the concrete hardens can be easily separated from the concrete. it can. In addition, 22 is a reinforcement frame.

In Japanese Unexamined Patent Publication No. 1-158179, as shown in FIG. 2, a water permeable material 10 made of a non-woven fabric disposed on a mold frame 16 side and a contact surface between the water permeable material 10 and concrete 18 are provided. Many pores 14 arranged on the side
And a film 12 made of a water-impermeable synthetic resin (polyethylene, polypropylene, ethylene-vinyl acetate, or the like) in which a perforated concrete formwork lining sheet is disclosed. According to this, since the concrete can be easily separated after hardening, and the concrete can be cured in a wet state, a high-strength, high-quality concrete structure can be obtained. Reference numeral 15 denotes an aggregate.

[0005]

However, in a large formwork method for repeatedly diverting such as a jump form method, it is important to improve the mold releasability in order to improve work efficiency.

In this regard, a method (sheet-in method) in which a sheet (for example, a polypropylene sheet or the like) having a small coefficient of friction is temporarily fixed to the inner surface of the mold and this is used as a trimming material has conventionally been adopted. Not only does it take time to attach the sheet to the sheet, but the sheet is thrown away once every time concrete is cast, which has the disadvantage of increasing the cost.

Accordingly, an object of the present invention is to solve the above problems and to provide a concrete casting formwork and a formwork attaching sheet which can be repeatedly used without disposable.

[0008]

In order to achieve the above object, a concrete casting mold according to the present invention has a water-resistant and alkali-resistant sheet attached to a concrete casting surface of a formwork body, and the sheet is previously attached to the sheet. It has a configuration impregnated with a setting retarder (claim 1).

[0009] The form-adhering sheet is a sheet to be adhered to the form surface in contact with the cast concrete, wherein the sheet is made of a water-resistant and alkali-resistant material and contains a setting retarder in advance. It has a configuration of impregnation (claim 2).

[0010]

The sheet according to claim 1 or 2 is impregnated with a setting retarder, so that even when the poured concrete hardens gradually and develops its strength, the surface of the concrete is retarded. Delays setting. For this reason, the adhesive force between the concrete and the sheet is reduced, and the mold can be easily removed from the mold and diverted.

Therefore, if the setting retarder is applied and impregnated to the sheet each time concrete is cast, the sheet can be repeatedly used and diverted, so that it is possible to save time and effort in attaching the sheet to the formwork body, thereby saving labor and cost. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, a concrete casting mold 1 of the present invention comprises a lightweight and strong mold body 2, and a water-resistant material having air permeability and water permeability firmly attached to a concrete casting surface of the mold body. Consisting of an alkali-resistant sheet 3,
The sheet 3 is impregnated with a setting retarder in advance.

The sheet 3 is made of a non-woven fabric or woven fabric made of a water-resistant or alkali-resistant material having a water-absorbing property, and is formed so that the sheet 3 is not peeled or broken by an external force during concrete casting. 2 Here, sheet 3
The brand name of the Sugimoto Sangyo is "Miznic Sheet". This sheet is made by bonding a special nonwoven fabric that does not allow cement particles to adhere to the air-encapsulation projection forming sheet made of a synthetic resin film, and backing the release paper by applying adhesive treatment on the back surface. It can be attached to the entire inner surface.

After the sheet 3 is fixed to the form body 2, the sheet is pre-impregnated with a setting retarder. Examples of the setting retardant include gluconic acid, sodium gluconate, lactic acid, ligninsulfonic acid, tannic acid, organic acids such as humic acid and salts thereof, lactones such as gluconodeltalactone, glucose, fructose, sucrose, and lactose. Saccharides such as maltose, maltose, dextrin, and glycogen; inorganic acids such as phosphoric acid, boric acid, and sodium silicofluoride; and salts thereof.

After the sheet 3 is impregnated with the setting retarder in advance as described above, concrete 4 is cast.

Since the excess water and air bubbles in the concrete 4 are discharged out of the formwork through the nonwoven fabric and the air-enclosed protrusion forming film sheet constituting the sheet 3, the excess water in the concrete surface layer is removed, and the water-cement ratio decreases. However, the development of the strength is accelerated, the demolding can be performed early, the generation of bubble avatars can be suppressed, and the concrete surface can be finished finely and beautifully.

Further, in the case of the present formwork 1, even when the poured concrete 4 gradually hardens and develops strength,
Since the sheet 3 in contact therewith is impregnated with a setting retarder, the setting of the surface of the concrete 4 is delayed by the setting retarder. For this reason, the adhesive force between the concrete 4 and the mold 1 (sheet 3) is reduced, and the mold can be easily removed from the mold and diverted even after sufficiently curing in an appropriate wet state. It becomes possible. Since the sheet is water-resistant and alkali-resistant, it can protect the formwork and increase the number of diversions.

Therefore, if the sheet 3 is coated and impregnated with a setting retarder every time concrete is cast, the sheet 3 can be repeatedly diverted. And cost reduction.

[0019]

In summary, according to the present invention, the following excellent effects can be obtained. 1) According to the concrete casting mold of the first aspect, since the sheet impregnated with the setting retarder is provided on the inner surface of the mold body, the cast concrete gradually hardens and develops strength. Even when the setting is performed, the setting of the surface portion of the concrete is delayed by the setting retarder. For this reason, the adhesive force between the concrete and the sheet is reduced, and the mold can be easily removed from the mold and diverted. Therefore, if the sheet is coated and impregnated with a setting retarder every time concrete is cast, the sheet can be repeatedly diverted, saving time and effort in attaching the sheet to the formwork body, thereby saving labor and reducing costs.

2) Since the setting sheet is impregnated in the sheet for applying a form according to the second aspect, the setting of the surface of the poured concrete can be delayed. For this reason, the adhesive force between the concrete and the sheet at the time of demolding can be reduced, and demolding can be facilitated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a concrete casting formwork of the present invention.

FIG. 2 is a cross-sectional view showing a conventional concrete casting formwork.

FIG. 3 is a cross-sectional view showing a conventional concrete casting formwork.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete casting formwork 2 Formwork main body 3 Sheet 4 Concrete

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Sone 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (58) Field surveyed (Int.Cl. ⁶ , DB name) E04G 9 / 00-9/10

Claims (2)

(57) [Claims] 1. A concrete casting formwork, wherein a water-resistant and alkali-resistant sheet is attached to a concrete casting surface of a formwork body, and the sheet is impregnated with a setting retarder in advance. 2. A sheet affixed to a formwork surface that comes into contact with cast concrete, wherein the sheet has water resistance,
A sheet for applying a formwork, wherein the sheet is an alkali-resistant material and has been impregnated with a setting retarder in advance.