JPH06226729A - Cylindrical concrete item, manufacture thereof and mold frame employed therefor - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for a cylindrical concrete capable of molding continuous cylindrical concrete, a mold frame employed therefor, and cylindrical concrete items. CONSTITUTION:A space 20 where cylindrical concrete is poured is defined by an outer mold frame 14 having an opening in its upper surface and an inner mold frame 16 of cylindrical synthetic resin or the like. Iron bars and the like are disposed ion the space 20, and after pouring concrete therein, the concrete is subjected to curing. As a result, a cylindrical concrete item can be obtained as in a state of the inner mold frame 16 spreading over the inside of the cylindrical concrete.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular concrete product, a method for producing the same, and a mold used for the same.

[0002]

2. Description of the Related Art Conventionally, a tubular concrete product called a so-called box culvert is known. This box culvert is buried in the ground in a connected state and used as an underpass, a waterway or a sewer. Conventionally widely known methods for manufacturing this type of box culvert are horizontal casting in which concrete is poured from the side of the product and vertical casting in which concrete is poured from the small edge of the product with the formwork standing upright. . A conventional manufacturing method for lateral driving will be described with reference to FIGS. 4 and 5. The box culvert formwork 2 comprises an outer formwork 14 and an inner formwork 8. The upper surface of the outer frame 14 is open, and one of the side plates 14a, 14a in the width direction (both may be both, but only one in the drawing) is slidable outward along the frame 13 with respect to the bottom plate 14b. is there. In addition, the end plates 15, 1
5 is rotatably supported by the bottom plate 14b via a hinge 18. In addition, the gable plate 15 may be slidable. Each side plate 14a, 14a of the outer mold 14 and each gable plate 15,
Each of them and 15 is detachably connected by a known connecting means. On the other hand, both ends of the inner mold 8 are supported by the end plates 15 of the outer mold 14 and the central opening 15a. The inner frame 8 has a rectangular cross section, and the upper plate 8a and both side plates 8b, 8b are a side-gate-shaped portal body, and the bottom plate 8c can be pulled out (separated) from the bottom surface of the portal body. It is provided. The gate-shaped body is formed by narrowing the lower ends of both side plates 8b, 8b, and the bottom plate 8c.
It is held open by. The outer mold 14
Since the inner formwork 8 is inserted into the openings 15a of the gable plates 15 and 15, since it is a heavy load, it is performed using a large-scale dedicated carrier device. The outer mold 14 and the inner mold 8 are each made of steel.

A cylindrical space is formed by the outer mold 14 and the inner mold 8. Concrete is put into this space, and the product is taken out after curing. Reinforcing bars are appropriately arranged in the space 6. When the bottom plate 8c of the inner mold 8 is pulled out after curing, the lower ends of the side plates 8b, 8b of the gate-shaped body are elastically deformed inward and peeled off from the inner surface of the concrete product. Then, the arch body is pulled out, both the end plates 15 and 15 are opened, and one or both side plates 14a of the outer frame 14 are slid (or rotated) in the outward direction to take out the concrete product.

[0004]

However, in the above-mentioned method for producing a tubular concrete product by horizontal casting, when a long concrete product is produced, a wide working space for pulling out the inner formwork in the lateral direction is secured. In practice, there was a limit to the molding of long concrete products. In addition, also in the manufacturing method of vertical striking, similarly,
There is a limited length because the inner formwork or product is pulled upwards. In addition, during horizontal driving, the space formed by the outer mold and the inner mold is divided into two, concrete flows into the bottom space from both sides, and the concrete joins at the center position of the inner bottom of the product. . The air in the space gathers at this confluent portion and becomes the inner bottom surface of the concrete product, and the finished surface becomes rough. For this reason, it is necessary to finish after molding. Further, when the inner form is pulled out laterally from one end of the product after curing, since the inner form is a heavy object, it is a troublesome work using a dedicated transfer device. Moreover, it is necessary to take out the concrete product after that, and many steps are required. Therefore, it is an object of the present invention to provide a method for manufacturing a tubular concrete and a mold used for the method, which can improve workability and can form a long tubular concrete. Further, another object of the present invention is to
An object of the present invention is to provide a tubular concrete product having a smooth running water surface, excellent watertightness and excellent chemical resistance.

[0005]

In order to solve the above problems, the present invention has the following constitution. The tubular concrete product is characterized in that the inner surface of the tubular body is covered with a tubular material such as synthetic resin. Further, as a manufacturing method, an outer mold and an inner mold are formed by arranging a cylindrical inner mold such as a synthetic resin in a box-shaped outer mold having an open upper surface to form a cylindrical concrete. And to form a space into which the concrete is poured, and by arranging reinforcing bars and the like in the space, and then pouring the concrete into the space where the reinforcing bars are arranged, the concrete is cured, and the concrete product after curing Is taken out from the outer mold, and the inner mold is characterized in that the inner side of the tubular concrete is covered. In addition, it is preferable to reinforce the inner formwork from the inside so as not to deform.
Further, a hole is formed in the inner mold surface located on the bottom side of the outer mold, and when the concrete is poured into the space formed by the outer mold and the inner mold, air is removed from the hole. Alternatively, the filling of the concrete may be confirmed by discharging the concrete from the hole. Furthermore, the formwork
A box-shaped outer mold with an open top surface and a cylindrical body made of synthetic resin, etc., in which the open ends are in contact with a pair of inner wall surfaces of the outer mold that face each other, and concrete or the like is poured into. An inner formwork that forms a space, pours concrete into the space by arranging reinforcing bars, etc., then cures the concrete, and keeps the inner surface covered when removed from the outer formwork after curing. And is provided.

[0006]

Next, the operation will be described. A cylindrical inner mold made of synthetic resin or the like is placed in the outer mold, and concrete is poured into the space formed by the outer mold and the inner mold. Reinforcing bars and the like are arranged in advance in the space. After pouring the concrete and curing it, the product is taken out from the outer mold. The inner formwork remains to cover the inner surface of the tubular concrete product. In addition, it is preferable to reinforce from the inside so that the inner formwork is not deformed. Also, make holes in the inner mold surface located on the bottom side of the outer mold to remove air from the holes and confirm that the concrete was evenly poured into the space when the concrete was discharged. be able to.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In this embodiment, the same members used in the above-mentioned conventional example are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 is a cross-sectional explanatory view of a molding frame. The mold 12 for molding is composed of an outer mold 14 and an inner mold 16. The upper surface of the outer mold 14 has an opening 14A. The inner formwork 16 is provided in the openings 15a of the gable plates 15, 15.
Support both ends of. A space 20 into which concrete is poured is formed by the outer mold 14 and the inner mold 16. Reinforcing bars are appropriately arranged in the space 20.

The inner frame 16 is made of, for example, a synthetic resin. As synthetic resin, reinforced plastic, polyethylene resin, vinyl chloride resin or FRP
Synthetic resin materials such as The inner formwork 16 may be made of metal or the like. On the other hand, when concrete is poured into the space 20 formed by the outer mold 14 and the inner mold 16, the mold 12
Although a large pressure is applied to the outer mold 14, since the outer mold 14 is made of steel, it is possible to sufficiently withstand the pressure of concrete by providing fin-shaped ribs, but when the inner mold 16 is made of synthetic resin, it is deformed. there's a possibility that. Therefore, it is necessary to reinforce the inner formwork 16 from the inside. As a reinforcing method, it is conceivable to apply a plurality of metal plates or the like from the inside and also to maintain the distance between the inner side surfaces of the inner formwork 16 with a rod or the like.

Further, a reinforcing inflator 22 may be arranged in the inner space of the inner mold 16 so as to inflate compressed air to inflate it. In this case, the reinforced inflatable body 22 contracts when air is removed, and it is easy to install and take it out inside the inner formwork 16. The number of the reinforcing inflatable bodies 22 may be one, or a plurality of them may be arranged.

A method for molding a concrete product with the above-described mold will be described. Inner mold 1 inside outer mold 14
6 is arranged, and a reinforcing bar or the like is arranged in the space 20 formed by the outer mold 14 and the inner mold 16. Also, the inner formwork 1
By the above-described reinforcing method from the inside of 6, the inner formwork 16 is reinforced so as not to be deformed by the pressure of the poured concrete. Then, concrete is poured into the space 20 through the opening 14A of the mold 12. After curing the poured concrete, the inner reinforcement of the inner mold 16 is removed, and one end plate 15 of the outer mold 14 is opened via the hinge 18,
One side plate 14a of the outer form 14 is slid outward to take out the tubular concrete product 10. In this tubular concrete product 10, the inner formwork 16 is not removed and becomes a part of the concrete product as it is.

When the concrete product is molded by the outer mold 14 and the inner mold 16, the concrete is filled in the space 2
It is difficult to judge whether or not it is full of zero. Therefore, a hole 16a is formed in the bottom surface 16A of the inner mold form 16. When molding the product with the outer mold 14 and the inner mold 16, when the concrete is poured into the space 20, the opening 1 in the space 20
The space is filled with concrete up to 4A.
When the concrete is poured into the space without any gap, it can be confirmed that the concrete is projected from the hole 16a and the concrete is evenly flowed into the space. Also, the hole 16a is
Also serves as an air vent hole. It should be noted that the hole 16a may be one having an appropriate size, but the holes 16a ... May be formed so as to be scattered on a straight line on the bottom surface 16A of the inner formwork 16.

In the above embodiment, the method of manufacturing a concrete product by the horizontal pouring method has been described, but the concrete product can also be manufactured by vertical pouring. The conventionally used outer die for vertical striking may be used, and the inner die 16 for vertical striking may be used instead of the conventional inner die 16 for vertical striking. Although various descriptions have been given with reference to the preferred embodiments of the present invention, the present invention is not limited to the above embodiments, and many modifications can be made without departing from the spirit of the invention. .

[0013]

INDUSTRIAL APPLICABILITY According to the present invention, since a concrete product can be directly molded using an inner mold made of synthetic resin or the like, the inner surface such as a running water surface can be made smooth, and watertightness and chemical resistance are excellent. Tubular concrete products. Particularly in a large so-called box culvert, the inner bottom surface does not become rough, and it is not necessary to finish after molding.
Further, unlike the conventional case, the work of pulling out the inner mold is not required, the workability is improved, and a long product can be formed, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a front explanatory view of a mold according to the present invention.

FIG. 2 is a vertical sectional view of a mold.

FIG. 3 is a front view of a tubular concrete product.

FIG. 4 is a front view of a conventional mold.

FIG. 5 is a side view of a conventional mold.

[Explanation of symbols]

 10 Tubular Concrete Products 12 Formwork 14 Outer Formwork 15 Gable Plate 16 Inner Formwork 16a Hole 18 Hinge

Claims (5)

[Claims] 1. A tubular concrete product, characterized in that the inner surface of the tubular body is covered with a tubular material such as synthetic resin. 2. A box-shaped outer mold having an open upper surface, on which a cylindrical inner mold made of synthetic resin or the like is placed, and by which the outer mold and the inner mold are formed to form cylindrical concrete. A space for pouring cylindrical concrete is formed, and reinforcing bars, etc. are laid in the space, concrete is poured into the space in which the reinforcing bars, etc. are reinforced, and then the concrete is cured. A method for producing a tubular concrete product, characterized in that the inner formwork is kept in a state of covering the inside of the tubular concrete. 3. The method for producing a tubular concrete product according to claim 2, wherein the inner formwork is reinforced from the inside so as not to be deformed. 4. An outer mold having a box-shaped outer mold having an open upper surface, the inner mold being horizontally arranged, and the inner mold surface located on the bottom side of the outer mold being provided with holes. When the concrete is poured into the space formed by the frame and the inner formwork, air is removed from the holes and the concrete is discharged from the holes to confirm the filling of the concrete. The method for producing a tubular concrete product according to claim 2 or 3. 5. A box-shaped outer mold having an open upper surface, and a cylindrical body made of synthetic resin or the like, the open ends of which are brought into contact with a pair of inner wall surfaces facing each other, and concrete or the like. While forming a cylindrical space into which the concrete was poured, after pouring concrete by arranging reinforcing bars and the like in the space, curing the concrete and covering the inner surface when removing it from the outer formwork after curing A formwork for a tubular concrete product, comprising: an inner formwork to be left as it is.