JPH0547374B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a concrete block having a cylindrical shape such as a box culvert, which prevents the formation of craters on the inner surface of the formed block in an extremely good and rational manner, and also allows molding. The form of the usage type has been significantly streamlined.

[Conventional technology]

Conventionally, there are the following forming methods for manufacturing concrete blocks exhibiting a cylindrical shape such as box culverts. The first method uses a formwork for producing a cylindrical block, which is composed of a box-shaped outer mold and a cylindrical middle mold mounted in the middle of the outer mold. However, if such a method is used, a crater 10 as shown in FIG. 3 will occur due to reasons described below. As a molding method that solves the problem of the generation of craters 10, there is a second method described below. This uses a medium-sized formwork with a ventilated bottom surface. Specifically, as shown in FIG. 4, the second method includes an outer mold 3 in which the side plate 1 and the end plate 2 are provided so as to be openable and closable, and the outer mold 3 is inserted into the through hole 4 of the end plate 2 horizontally. It is equipped with a medium size 5 to be attached. The medium size 5 is divided into a bottom frame 8 forming the bottom surface thereof, and a portal frame 7 provided with an opening 6 into which the bottom frame 8 is attached. The cylindrical block 9 is formed by pouring concrete into a horizontal cylindrical cavity formed when the outer mold 3 and the middle mold 5 are assembled. In addition, the medium-sized 5 can be constructed by removing the bottom frame 8 and using the gate-shaped frame 7.
By squeezing the cylindrical block, it can be removed from the formed cylindrical block. Furthermore, in the second method, the forming surface of the bottom frame 8 is formed by a punching metal 11 provided with a large number of ventilation holes, and during molding, a fabric 12 is placed on the outside of the punching metal 11.
Since the particles are discharged through the grains of the fabric, the formation of craters 10 as shown in FIG. 3 is prevented. However, in the second method described above, the surface formed by the bottom frame 8 becomes a rough surface, and the crater hidden under the brittle layer that becomes this rough surface becomes a block. When the strength is reduced and an impact is applied, a problem arises in that the fragile layer collapses and a crater appears. As a molding method that aims to eliminate such problems, there is a third method as described below. As shown in FIG.
2, a cylindrical medium mold 5 equipped with a temporary bottom frame 23 is horizontally mounted on the outer mold 3 to assemble the mold 14,
Concrete 16 is poured into the empty space 15 of the formwork 14, and before the concrete hardens, the temporary bottom frame 23 is removed, and this temporary bottom frame 23 is moved horizontally and removed. Insert the bottom frame 8 horizontally into the middle mold 5, push out the excess concrete in the raised part 19 formed in the recess 22 outside the form 14, and then insert the regular bottom frame 8 into the middle mold 5. 5 to solidify the concrete within the formwork 14.

[Problem to be solved by the invention]

In the first method described above, that is, the method using a formwork in which the medium mold is mounted horizontally, a space whose upper part is not open is formed between the bottom surface of the medium mold and the bottom surface of the outer mold. Therefore, when the air, excess water, cement paste, sand, etc. contained in the concrete (including mortar; the same applies hereinafter) that has flowed into this space moves upward, the bottom of the medium size prevents its discharge. Large air bubbles and water bubbles are formed in the area that contacts the bottom of the medium-sized concrete, and the slump value of the concrete in this area becomes high. If the concrete solidifies in this state, craters 10 as shown in Figure 3 will occur on the inner surface of the formed cylindrical block, which will significantly reduce the quality of the product. A problem will arise. Next, regarding the second method described above, that is, the method using a formwork with a structure as shown in FIG.
It is said to be extremely effective in preventing craters from forming on the inner surface of cylindrical blocks. However, when molding with a formwork having such a structure, the bottom frame 8
As water in the concrete in contact with the concrete is excessively removed, a fragile layer with a coarse structure is formed in the contact area, and after the fragile layer loses its fluidity, it rises from below. If water remains in the lower part of the weak layer, it will lead to a situation where the concrete hardens. As a result, the surface formed by the bottom frame 8 becomes a rough surface, and craters hidden under the roughened brittle layer reduce the strength of the block, causing the brittle layer to cave in when an impact is applied. This inevitably caused the problem of craters appearing. As for the third method mentioned above (the method shown in Figure 5), by adopting such a method, air bubbles and water bubbles that occur when concrete is poured into the formwork are reliably removed, and therefore, This solves problems such as the occurrence of craters, rough surfaces, and brittle layers on the inner surface of the cylindrical block, and makes it possible to manufacture high-quality cylindrical blocks. In other words, the third method solves the problems of the first and second methods described above, and can be said to be superior as a method for forming cylindrical blocks. However, the problem with the third method is that it uses two bottom frames, the temporary bottom frame 23 and the regular bottom frame 8,
Since these parts are replaced based on the required process, the work is extremely complicated and unreasonable, and at the same time, the manufacturing cost of the mold is inevitably increased. The present invention is an improvement on the third method, and is characterized by solving the above-mentioned problems.

[Means to solve the problem]

The method for manufacturing a cylindrical block according to the present invention is based on the following means to solve the above-mentioned problems. A cylindrical medium 5 in which a pre-filled concrete forming frame part N is removably attached to the lower surface of a bottom frame part M, and the bottom frame part M is detachably attached.
are installed horizontally on the outer mold 3 to assemble the formwork 14. Then, concrete 16 is poured into the empty space 15 of the formwork 14, and before the concrete hardens, the pre-filled concrete forming frame part N and the bottom frame part M are poured.
Once removed, the bottom frame M from which the pre-filled concrete forming frame N was separated is placed again into the medium-sized 5
Insert inside. As a result, excess concrete in the pre-heavy portion L formed by the pre-heaped concrete forming frame portion N is scraped out. After that, the bottom frame part M is fixed to the medium mold 5, and the concrete in the mold 14 is allowed to solidify.

[Effect]

According to the method according to the present invention, the bottom surface of the medium 5 and
Air and excess water rising from the concrete that has flowed into the space between the outer mold 3 and the bottom surface of the outer mold 3 are generated in the pre-heap part L formed by the pre-heap concrete forming frame part N, and then the bottom frame part M is When the preparatory portion L is scraped out, it is removed from the formwork along with the concrete in the portion. After the bottom frame part M is removed, it is fixed to the middle mold 5 to form the surface of the block in that part, so that good molding is possible without creating craters or brittle layers on the surface. This results in a surface area being obtained.

【Example】

Embodiments of the present invention will be described in detail with reference to the drawings as follows. FIG. 1 shows a molding process according to an embodiment of the present invention. Incidentally, the present invention is applied to the outer mold 3 as shown in FIG.
Please also refer to the figure. First, as shown in FIG. 1A, the side plate 1 and end plate 2 are erected on the base 13, and the box-shaped outer mold 3 is assembled.
A gate frame 7 of medium size 5 is inserted into the through hole 4 of the end plate 2, and the gate frame 7 is expanded to form a bottom in which a pre-filled concrete forming frame N is removably attached to the bottom surface of the opening 6. The frame portion M is fitted and fastened to assemble the formwork 14. Next, as shown in FIG. 1B, concrete 16 having a slump value of about 4 to 10 is poured into the cylindrical cavity 15 of the formwork 14 while being vibrated and compacted. When about 10 to 60 minutes have passed after the completion of pouring, air, some water, cement, and sand gather at the bottom of the medium mold 5 and bubbles 17 are generated, causing a gap of 3 to 5 mm from the contact surface with the bottom frame M. The concrete layer with a slump value of 12
It will be about. At the above point, as shown in FIG. 2C, the formwork 14
Remove the pre-filled concrete forming frame part N and the bottom frame part M from. In this state, bubbles and water bubbles 17 are generated in the pre-heaped concrete forming part L formed by the pre-hewn concrete forming frame part N, and the concrete layer 3 to 5 mm from the contact surface with the bottom frame part M is , the slump value is around 12. Next, as shown in FIG. By inserting it horizontally from one end of
Scrape out. Based on the above scraping operation, as shown in FIG.
Excrete outside. Finally, while holding down the bottom frame part M so as not to lift it up, it is rubbed back and forth on the concrete surface about 20 times to blend in with the concrete surface, and then it is fixed to the portal frame 7 and cured. After curing is completed, the formwork 14 is opened and the cylindrical block 9 is demolded.

【Effect of the invention】

According to the present invention, it is possible to reliably remove air bubbles and water bubbles that occur when pouring concrete into the formwork, which can prevent the formation of craters, rough surfaces, brittle layers, etc. on the inner surface of the cylindrical block. This will help eliminate situations like this. Therefore, it becomes possible to manufacture a high-quality cylindrical block that is dense, has high strength, and has excellent surface properties. Furthermore, the present invention provides a bottom frame part M having a pre-filled concrete forming frame part N removably attached to the lower surface thereof,
It is separably attached to the cylindrical medium 5, and scrapes out excess concrete in the pre-heap portion L formed by the pre-heap concrete forming frame portion N by separating and detaching the pre-heap concrete forming frame portion N. Since this is done through the bottom frame M, the shape of the mold can be significantly streamlined. That is, when the temporary bottom frame 23 with the recess 22 on the lower surface and the bottom frame 8 are replaced in response to the work process as in the conventional method shown in FIG. Formwork manufacturing problems, such as the precise formation of the recess 22 with the required depth relative to the temporary bottom frame 23, are eliminated. Furthermore, with such a conventional method, the temporary bottom frame 23 also needs to have the same strength as the bottom frame 8, and therefore,
Manufacturing costs increase. On the other hand, the pre-filled concrete forming frame N in the present invention only plays the role of a kind of spacer, so it does not require that much strength, and since it is a simple rectangular frame etc., the material cost is also reduced. This is minimized, resulting in a significant cost reduction compared to the conventional example.

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal sectional view showing an embodiment of the present invention in the order of steps, Fig. 2 is a perspective view showing a pre-filled concrete forming frame part N and a bottom frame part M used in the present invention, and Fig. 3 is a FIG. 4 is an exploded perspective view of the formwork used in the conventional method, and FIG. 5 is an explanatory vertical sectional view showing another conventional example in the order of steps. 1... Side plate, 2... End plate, 3... Outer mold, 4...
Through hole, 5...Medium size, 6...Opening, 7...Portal frame, 8...Conventional bottom frame, 9...Cylindrical block, 1
0... Crater, 11... Punching metal,
12...Fabric, 13...Base, 14...Formwork, 1
5... Blank space, 16... Concrete, 17... Blister, 18... Mortar, 19... Swelling part,
22... Recess, 23... Temporary bottom frame, M... Bottom frame portion, N... Pre-filled concrete forming frame portion, L...
Preparation section.

Claims (1)

[Claims] 1 A cylindrical medium 5 in which a pre-filled concrete forming frame part N is removably attached to the lower surface of a bottom frame part M, and the bottom frame part M is detachably attached.
are installed horizontally on the outer mold 3 to assemble the formwork 14, and concrete 16 is placed in the empty space 15 of the formwork 14.
is poured, and before the concrete solidifies, the pre-filled concrete forming frame part N and the bottom frame part M are once removed, and then the bottom frame part M from which the pre-filled concrete forming frame part N has been separated is reinstalled. , by inserting it into the medium mold 5 to scrape out the excess concrete of the pre-heaped part L formed by the pre-hewn concrete forming frame part N, and then remove the concrete from the pre-heaved concrete forming frame part N.
A method for manufacturing a cylindrical block, characterized in that the concrete in the formwork 14 is solidified by fixing the block to a medium size 5.