JPH10315216A - Concrete product form structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete product form structure which can prevent the setting of air into ready-mixed concrete within a form main body even when air is expanded within a hollow box removing form part due to heating in the case of steam curing, whereby the smoothness of the surface of a concrete product is maintained and the formation of holes in the concrete product by escaping air is prevented. SOLUTION: The structure for a form for producing a concrete segment having a recessed portion formed in the surface thereof is provided in which when a hollow box removable form portion 12 is fixed inside a form main body 11 for forming a main part of a concrete segment, a through passageway 14a is formed at a position along a central axis of a tightening bolt 14 so as to allow the interior space of the hollow box removable form portion 12 to communicate with the atmospheric air via the through passageway 14a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete product formwork structure, and more particularly to a formwork for manufacturing a concrete product through a steam curing process.

[0002]

2. Description of the Related Art It is well known that a concrete segment 1 as shown in FIG. 5 is used as a lining when a tunnel is constructed by a shield method or the like. There are various methods of manufacturing the concrete segment 1. As one manufacturing method, after the fresh concrete is poured into the segment form, steam curing is performed to promote concrete hardening, and the concrete is poured into the segment form during the steam curing. There is a method of manufacturing the concrete segment 1 through a step of heating the ready-mixed concrete at about 65 ° C.

In this type of concrete segment 1, for example, a recess 2 for a ring joint or a segment joint is formed on an end face or a side face. When the concrete segment 1 is manufactured, such a recess 2 is formed by forming a steel plate called a hollow boxless formwork portion 4 inside a formwork body 3 forming a main portion of the segment 1 as shown in FIG. It is formed by fixing a component processed into a mold.

Normally, the hollow box-extracting formwork 4 is attached to the mold main body 3 by forming a bolt through hole 5 in a close contact portion between the mold main body 3 and the hollow box-extracting formwork 4, The bolts 6 are inserted through the through holes 5 and fastened and fixed with the nuts 7 so that mutual fixing is achieved.

[0005]

However, in such a conventional concrete segment formwork, after the hollow boxless formwork portion 4 is completely sealed by the components of the formwork body 3, the mold is formed on the formwork. When the concrete 8 is poured and steam curing is performed, the air inside the hollow box blanking mold section 4 expands due to heating during steam curing, and the mold body 3 and the hollow box blanking are removed through the bolt insertion holes 5. In some cases, the concrete was squirted from the close contact portion with the formwork portion 4 to the ready-mixed concrete 8 in the formwork body 3.

[0006] The air 9 jetted into the ready-mixed concrete in the segment form as described above rises to the surface of the concrete 8, and as a result, a hole is formed in the segment surface after hardening of the concrete to roughen the surface. In some cases, there is a problem in that the holes 9 pass through the inside of the concrete due to the jetted air 9 and may lead to water leakage after the segment construction.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem. Even when the air inside the hollow box-forming mold section expands due to heating during steam curing, the inside of the mold body remains. It is an object of the present invention to provide a concrete product formwork structure which prevents the air from escaping into ready-mixed concrete, thereby maintaining the smoothness of the concrete product surface and preventing the formation of air escape holes inside the concrete product. .

[0008]

SUMMARY OF THE INVENTION The present invention is a concrete product formwork structure, which is configured as follows to solve the above-mentioned technical problems. That is, the present invention
A structure of a formwork for producing a concrete product having a concave portion formed on the surface, the formwork body forming a main part of the concrete product, and a concrete product fixed inside the formwork body and manufactured. It is characterized by comprising a hollow box-forming frame forming a concave portion and air venting means for communicating the internal space of the hollow box-forming frame with the atmosphere.

<Concrete Structure of the Present Invention> The concrete product formwork structure of the present invention is composed of the above-mentioned essential components. However, the concrete product formwork can be established even when the components are specifically as follows. The specific constituent element is an attachment in which one end is located in the hollow box-extracted formwork when fixing the hollow box-exposed formwork to the formwork main body, and the other end is located outside the formwork main-body. A through passage formed in the bolt can be used as the air vent. Further, the air bleeding means may be an air bleed hole formed in the hollow box dies and the frame body.

[0010] According to the concrete product formwork structure of the present invention, when the air inside the hollow boxless formwork expands due to heating during steam curing, the air, for example, passes through the hollow boxless formwork to the formwork. Escape to the atmosphere through a through passage formed in the mounting bolt fixed to the main body. That is, since the inside of the hollow box-forming form is in communication with the atmosphere through the through-path, the inflated air in the hollow box-forming form immediately escapes to the atmosphere, and as a result, the pressure in the hollow box-forming form increases. Therefore, the air expanded into the ready-mixed concrete in the form body is not pushed out.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete product formwork structure of the present invention will be described in more detail below with reference to an embodiment shown in the drawings. FIG. 1 shows a main part of a concrete segment formwork 10 according to one embodiment of the present invention. The concrete segment form 10 includes a form body 11 that forms the main part of the concrete segment.

The form body 11 itself has been used in the manufacture of this type of concrete segment,
Since it is already well known, detailed description is omitted. As described above, a recess 2 for a ring joint or a segment joint is formed on an end face or a side face of the concrete segment 1 used as a lining when a tunnel is constructed. A hollow box-cutting formwork portion 12 is fixed inside a predetermined position of the formwork body 11.

The frame body 11 of the hollow boxless mold section 12
For fixing to the frame body, a bolt through hole 13 is formed in a tight contact portion between the mold body 11 and the hollow box removing mold frame portion 12, a tightening bolt 14 is inserted into the bolt through hole 13, and the tightening bolt 14 is rotated. The nuts 15 are screwed together to fix each other. In this case, one end of the tightening bolt 14 is located inside the hollow box blanking mold frame portion 12, and the other end is located outside the mold body 11.

On the shaft center line of the tightening bolt 14,
As shown in FIGS. 1 and 2, a through-passage 14 a that penetrates the entire length of the tightening bolt 14 is provided. As a result, the hollow box-extracting formwork portion 12 is
Even after the open portion of the hollow box-exposed mold portion 12 is closed and sealed by the components of the mold body 11, the inside of the hollow box-extracting mold portion 12 is fixed to the through-hole 14a formed in the tightening bolt 14 after being attached to the mold body 11. Through the atmosphere.

Therefore, the through passage 14a functions as an air bleeding device for bleeding air from the hollow box piercing frame 12. Needless to say, the through-passage 14a functioning as such an air venting means may be located at a position other than the axis center line, as is apparent from its role.

According to the concrete segment formwork structure according to the present embodiment thus configured, after the ready-mixed concrete 8 is poured into the segment formwork, steam curing is performed to promote concrete hardening. When the ready-mixed concrete poured into the segment formwork at this time is heated at, for example, about 65 ° C., and the air in the hollow box-forming formwork section 12 expands, the expanded air passes through the through passage 14 a formed in the tightening bolt 14. Escape to the atmosphere.

Therefore, the pressure in the hollow box-forming frame 12 is always kept at the same level as the atmospheric pressure. As a result, the air in the hollow box-forming frame 12 expanded at the time of heating flows through the bolt holes 13 and the like. A hole is formed in the segment surface of the hardened concrete without hardly penetrating into the ready-mixed concrete 8 through a small gap between the hollow box-exposed mold frame portion 12 and the close contact portion between the mold body 11, and the surface is roughened. Or formation of an air passage inside the concrete can be prevented.

In the concrete segment formwork structure according to the above-described embodiment, the air release means for communicating the internal space of the hollow box formwork portion 12 with the atmosphere is constituted by a through passage 14a formed on the center axis of the tightening bolt. However, as shown in FIG. 3, an air vent hole 17 penetrating the plate member 16 closing the open portion of the hollow box emptying mold frame portion 12 and the close contact portion between the component 11a of the mold body 11 is provided. Is also good.

At this time, the plate member 16 for closing the open portion of the hollow box-extracting formwork portion 12 and the component 1 in the formwork body 11
In order to prevent the leakage of concrete moisture from the contact portion with the plate member 16a, the plate member 16 at the inner peripheral portion of the air vent hole 17 is formed.
It is preferable to provide an O-ring 18 at the contact portion between the component and the component 11a.

In the concrete product formwork structure according to the above-described embodiment, the manufacture of a concrete segment used as a lining of a tunnel has been described as an example. However, the present invention is not limited to this. It goes without saying that the present invention can be applied not only to the production of concrete segments to be used but also to the production of concrete products that undergo steam curing.

[0021]

As described above, according to the concrete product formwork structure of the present invention, the hollow boxless formwork portion in the case of manufacturing a concrete product having a recess formed on its surface is communicated with the atmosphere. After the fresh concrete is poured into the product form, for example, when the raw concrete poured into the product form is heated when steam curing is performed to accelerate concrete hardening, the hollow box punching die The air in the frame does not enter the ready-mixed concrete through a small gap between the hollow boxless die frame and the tightly-fitted portion of the die body through the bolt holes and the like.

As a result, holes are formed in the surface of the product after hardening of the concrete, and the surface does not become rough, or an air passage is not formed in the concrete, thereby producing a high quality concrete product. be able to.

[Brief description of the drawings]

FIG. 1 is a fragmentary fragmentary view showing a main part of a concrete segment formwork according to an embodiment of the present invention.

FIG. 2 is a front view showing a mounting state of a tightening bolt used in the concrete segment formwork shown in FIG. 1;

FIG. 3 is a fragmentary sectional view schematically showing a main part of a concrete segment formwork according to another embodiment of the present invention.

FIG. 4 is a fragmentary sectional view schematically showing a main part of a conventional concrete segment formwork.

FIG. 5 is a perspective view showing an example of a conventional concrete segment used as a lining when constructing a tunnel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete segment 2 Concavity 6 Tightening bolt 7 Nut 8 Fresh concrete 10 Concrete segment formwork 11 Formwork body 12 Hollow boxless formwork part 13 Bolt through hole 14 Tightening bolt 14a Penetrating path 15 Nut 16 Closure plate 17 Air vent hole 18 O -Ring

Claims (3)

[Claims] 1. A structure of a formwork for manufacturing a concrete product having a concave portion formed on a surface thereof, comprising: a formwork body forming a main part of the concrete product; A concrete product form structure comprising: a hollow box-forming form part forming a concave portion in the concrete product thus formed; and air vent means for communicating the internal space of the hollow box-forming form part with the atmosphere. . 2. The method according to claim 1, wherein one end of the air venting means is located inside the hollow box emptying form when fixing the hollow box emptying form to the mold main body, and the other end is located outside the mold main body. The concrete product formwork according to claim 1, wherein the concrete product formwork is a through passage formed in the mounting bolt. 3. The concrete product formwork structure according to claim 1, wherein said air release means is an air release hole formed in said hollow box release formwork portion and said formwork body. [0000]