JPH0868141A - Permanent formwork for concrete - Google Patents

Abstract

PURPOSE: To resolve the defective sticking caused by breathing water or the like by providing fine recessed grooves having a prescribed width and an irregularity difference continuously in the longitudinal direction on the faces of a formwork to be kept in contact with concrete. CONSTITUTION: Connecting coupling step sections 1D, 1D are provided on the end faces 1C, 1C of a hollow or solid plate-like body 1A made of fiber reinforced cement, and multiple protruded stripes 2...2 are provided on the faces 1B to be kept in contact with placed concrete in this permanent formwork for concrete 1. Multiple stripes 2...2 of the faces 1B to be kept in contact with concrete and fine recess grooves 3...3 having the width B and the depth with an irregularity difference of 0.1-3mm against the formwork surface 1B...1B are formed by extrusion molding continuously in the width direction. Bubbles and breathing water are stopped at these portions by the fine recess grooves 3...3 due to the surface tension and capillary tube phenomenon, and the upward shift is prevented. The generation of water channels between concrete and the permanent formwork for concrete 1 is prevented, and the adhesion is improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved permanent formwork for concrete.

[0002]

2. Description of the Related Art It has been proposed to use a permanent formwork made of fiber reinforced cement for concrete construction in place of a conventional plywood formwork as a building formwork for concrete walls (for example, Japanese Patent Laid-Open No. 3-293473). Bulletin). This type of concrete formwork has the advantage that it can be integrated with the concrete to be poured and the formwork will be integrated with the walls or columns of the building structure as it is, so that the subsequent frame removal work can be omitted. . By the way, in order to improve the adhesiveness of the permanent formwork for concrete construction with the concrete to be poured, it is considered to improve the physical adhesiveness by providing a ridge with a rectangular cross section or an inverted trapezoidal shape on the back surface. Has been.

[0003]

However, these permanent formwork for concrete construction may be arranged in a horizontal direction in addition to a vertical direction depending on the building structure such as wall surfaces and beams, and the continuous direction of the ridges may be used. There is a problem that the adhesion between the cast concrete and the permanent formwork for concrete construction may be poor depending on the correlation between the placement direction and the placement direction. That is, after pouring the concrete, the breathing water in the concrete is concentrated along with the air bubbles contained in the concrete at the contact interface with the permanent formwork for concrete construction, and has the property of attempting to rise through this interface. For this reason, especially when the permanent formwork for concrete is arranged in the vertical direction, there is a problem that the adhesive force with the cast concrete is significantly impaired despite the provision of the ridges.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has been made for the purpose of improving the adhesion to concrete in a permanent formwork for concrete work.

[0005]

That is, the permanent formwork for concrete according to the present invention has a hollow or solid fiber-reinforced cement plate-shaped body 1A in a longitudinal direction on a surface 1B in contact with concrete to be cast. Plural number of ridges 2 ... 2
In the permanent formwork 1 for concrete which is provided with,
A small groove 3 continuous in the length direction and having a width and unevenness difference of 3 mm or less and 0.1 mm or more on the surface 1B that contacts the concrete to be cast.
... 3 is continuously provided in the width direction.

In another aspect of the invention, minute concave grooves 3 ... 3 which are continuous in the lengthwise direction and have a width and unevenness difference of 3 mm or less and 0.1 mm or more are provided only on the mold surface 1B between a plurality of ridges 2. It is characterized by being formed. Furthermore, in the above first and second inventions, the cross-sectional shape of each of the minute concave grooves 3 ... 3 is a dovetail groove, and the sectional shape of the minute concave grooves 3 ...
It is characterized by being constituted by a combination of grooves having different heights and widths.

[0007]

In the invention of claim 1, the surface 1B of the permanent formwork for concrete which is in contact with the concrete is continuous in the lengthwise direction with the minute concave grooves 3 ... 3 having a width and unevenness difference of 3 mm or less and 0.1 mm or more. The reason for this is to prevent air bubbles and breathing water from stopping at the portion due to the surface tension and the capillary phenomenon by the minute grooves 3, ... Therefore, it is possible to prevent water from being formed between the concrete and the permanent formwork for concrete, which improves the adhesion between the concrete and the permanent formwork for concrete.

The widths and depths of the fine recessed grooves 3 ... 3 are set to 3 mm or less because generally the diameter of bubbles contained in the breathing water of the concrete to be cast is 3 mm or less. This is because air bubbles rise along the grooves of the grooves 3 ... 3 so that water can be easily produced and the adhesion between concrete and the permanent formwork for concrete cannot be improved. Also, if the groove is 3 mm or less, it may be a fine groove, but if it is too small, it becomes difficult to form a minute groove, and since it is substantially the same as a smooth surface and the effect cannot be obtained, the minimum is 0.1 mm. mm is suitable. In addition,
The cross-sectional shape of the minute concave grooves 3 ... 3 is not particularly limited as long as it is a shape that can exhibit the above-mentioned action, such as a triangular shape, a rectangular shape, and a semicircular shape.

In the second aspect of the invention, the minute concave grooves 3 ... 3
3 is provided only on the mold surface 1B between the plurality of ridges 2 ... 2 so that even if the concrete permanent molds 1 are stacked during transportation and storage, the minute concave grooves 3 ... 3 have a plurality of ridges 2 ... 2 protects from contact with other objects, and the minute grooves 3 ... 3 prevent other objects from being scratched or the minute grooves 3 ... 3 from being scratched away or damaged.

In the invention of claim 3, the minute concave grooves 3 ... 3
The cross-sectional shape of each groove is formed in the shape of a dovetail groove in order to further improve the catching property of breathing water due to the capillary phenomenon. In the invention of claim 4, the cross-sectional shape of the minute recessed grooves 3 ... 3 is formed by a combination of grooves having different heights and widths, even if the bubble diameters contained in the breathing water vary, the breathing water due to the capillary phenomenon. This is for surely supplementing.

[0011]

Embodiments of the present invention will be described below. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of the embodiment of FIG. 1, and FIGS. 3 to 6 are enlarged sectional views of an essential part of another embodiment.

[Embodiment 1] A fiber-reinforced cement plate-shaped body 1A which is a hollow or solid body (solid body in the illustrated example) as shown in FIG. In the permanent formwork 1 for concrete, in which the parts 1D and 1D are provided and a plurality of ridges 2 ... 2 are provided on the surface 1B which is in contact with the concrete to be cast, the surface in contact with the concrete, that is, the ridges 2 ... 2 2 and a plurality of ridges 2 ... 2 and a mold surface 1B ... 1B as shown in FIG.
3 are provided with a plurality of fine grooves 3 having a triangular cross section of 1 mm. The minute concave grooves 3 ... 3 were extruded at the same time when the permanent mold for concrete 1 was extruded.

[Embodiment 2] Micro concave groove 3 in Embodiment 1
The permanent mold 1 for concrete was molded in the same manner as in Example 1 except that the cross-sectional shape of 3 was rectangular as shown in FIG.

[Embodiment 3] Micro concave groove 3 in Embodiment 1
A permanent mold for concrete 1 was molded in the same manner as in Example 1 except that the cross-sectional shape of 3 was formed into a dovetail groove shape as shown in FIG.

[Embodiment 4] Micro recessed groove 3 in Embodiment 1
The permanent mold 1 for concrete was molded in the same manner as in Example 1 except that the cross-sectional shape of 3 was a combination of a triangular shape and a dovetail groove shape as shown in FIG.

[Embodiment 5] Micro recessed groove 3 in Embodiment 1
As shown in FIG. 6, the sectional shape of 3 is a large triangular protrusion 3A having a height of 3 mm and a small triangular protrusion 3 having a height of 1 mm.
A permanent formwork 1 for concrete was molded in the same manner as in Example 1 except that B and B were combined in a ratio of 1 to 3.

[Embodiments 6 to 10] A fiber-reinforced cement plate-shaped body 1A which is a hollow or solid body (solid body in the illustrated example) as shown in FIG. 1, and is joined to its end faces 1C, 1C. In the permanent formwork 1 for concrete, which is provided with the engaging step portions 1D and 1D, and is provided with a plurality of ridges 2 ... 2 on the surface 1B which comes into contact with the concrete to be placed, a plurality of ridges 2 ... 2 are provided. 2B, only a plurality of micro recessed grooves 3 having a triangular cross section with a width B and a depth D of 1 mm as shown in FIGS.

[Comparative Example] A permanent mold 1 for concrete was formed in the same manner as in Example 1 except that the minute groove 3 was not provided in the permanent mold 1 for concrete in Example 1.

Next, for Examples 1 to 10 and Comparative Example, as shown in FIG. 7, the formwork 1 was assembled in the vertical arrangement X, the horizontal arrangement Y, and the bottom arrangement Z, and concrete was actually placed 3 Form 1 with a diamond cutter after a week
Cut out a 10 cm square including the placed concrete P,
As shown in FIG. 8, jigs Q and Q were adhered to the concrete surface P and the surface of the mold 1 with an epoxy resin adhesive, respectively, and subjected to a tensile tester to test the adhesive force. The results are shown in Table 1.

[0020]

[Table 1] * 1 in the table indicates that the concrete surface of concrete form 1 was destroyed. The same * 2 indicates that interfacial peeling between concrete and form 1 occurred. In addition, no mark indicates the value when the concrete layer was destroyed.

As is clear from Table 1, in the case of the permanent mold for concrete 1 of the present invention, the adhesiveness to the concrete to be cast is small even in the case of the arrangement in the X direction where water can be produced most easily. About 2 to 4 times as compared with the comparative example without the groove
It was found that the adhesive strength was doubled and the adhesiveness to the concrete P was excellent. In the comparative example, interfacial peeling occurred, but in the example, there was no interfacial peeling, and it was confirmed that water supply with breathing water was not possible. still,
The cross section of the sample of Example 6 which was forcibly peeled off at the interface confirmed that bubbles of 1 to 2 mm were attached.

[0022]

As described above, the permanent mold 1 for concrete according to the invention of claim 1 is provided with the micro-grooves 3 so that it is difficult to produce water due to the surface tension of breathing water or the capillary phenomenon. It has excellent adhesiveness with and can build a strong structure. In addition, in the case of the invention of claim 2, since the minute recessed grooves 3 ... 3 are not exposed on the back surface of the mold, there is no possibility that they will come into contact with other objects and damage them, thus facilitating the management of transportation and storage. Have. In the case of the invention of claim 3, since it is the dovetail-shaped minute concave grooves 3 ... 3, the adhesiveness with the concrete that has penetrated between the minute concave grooves is improved, and there is an effect that a more excellent adhesive force is obtained. .
In the case of the invention of claim 4, there is an effect that a uniform adhesive force can be obtained even if the diameters of the bubbles contained in the cast concrete vary.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the embodiment shown in FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of another embodiment.

FIG. 4 is an enlarged cross-sectional view of a main part of another embodiment.

FIG. 5 is an enlarged sectional view of an essential part of another embodiment.

FIG. 6 is an enlarged cross-sectional view of a main part of another embodiment.

FIG. 7 is a perspective view showing a state in which a mold is assembled.

FIG. 8 is an explanatory diagram of an adhesive strength test device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Permanent formwork for concrete 1A ... Fiber-reinforced cement plate-shaped body 1B ... Surface that contacts concrete to be cast 1C ... End surface 1D ... Engaging step portion for joining 2 ... Plural ridges 3 ... Micro concave groove P … Concrete placed Q… Jig

Claims (4)

[Claims] 1. A plurality of ridges 2, 2, which are continuous in the length direction, are provided on a surface 1B of a plate-shaped body 1A made of a fiber-reinforced cement, which is hollow or solid, and which is in contact with concrete to be cast. In the permanent formwork 1 for concrete, on the surface 1B in contact with the concrete to be cast, minute concave grooves 3 ... 3 having a width and unevenness difference of 3 mm or less and 0.1 mm or more are continuously provided in the width direction. A permanent formwork for concrete characterized by 2. Micro-grooves 3 ... 3 continuous in the lengthwise direction and having a difference in width and unevenness of 3 mm or less and 0.1 mm or more are provided only on the mold surface 1B between a plurality of ridges 2. The permanent formwork for concrete according to claim 1. 3. The permanent formwork for concrete according to claim 1 or 2, wherein each of the minute concave grooves 3 ... 3 has a dovetail groove in cross section. 4. The permanent formwork for concrete according to claim 1 or 2, characterized in that the cross-sectional shape of the minute concave grooves 3 ... 3 is constituted by a combination of grooves having different heights and widths. .