JPH0338309A - Manufacture of concrete product - Google Patents

Abstract

PURPOSE:To manufacture a beautiful concrete product without aerated marks by overlapping a water absoring paperboard on a bottom plate of a mold, placing a concrete material, applying vibration and compaction, pressurizing the concrete material from above, turning over the mold and releasing, and removing the paperboard. CONSTITUTION:A mold 2 is placed on a bed 1 and a water absorbing paperboard 3 is overlapped on a bottom plate 2a of the mold 2. A soft regenerated paper, cut into same size as the bottom plate 2a or larger, is used for said paperboard 3. Mortar 4 is fed in and smoothed uniformly on the paperboard 3, over which a stiff consistency concrete material 5 is placed to be swollen out of the mold 2, and vibration and compaction are carried out. Then, the upper surface of the concrete material 5 is pressed by a finishing board 6, and then the finishing board 6 is turned to smooth the surface and vibration and compaction are carried out. Then, the mold 2 is transferred from the bed 1 to a curing site and turned over immediately and released. Finally the paperboard 3 containing the water content adhered onto a molded pavement concrete plate is released and curing is carried out. Thus, a beautiful concrete product without aerated marks on its surface is manufactured.

Description

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

The present invention provides clean pavement blocks with no bubble marks on the surface.
This article relates to a method for manufacturing concrete products such as gutter covers.

[Conventional technology]

After putting hardened concrete into the formwork and compacting it by vibrating it, the concrete is pressurized from above with a finishing machine and leveled out.
A method of manufacturing a concrete product is known in which the formwork is inverted and immediately demolded.

[Problem to be solved by the invention]

In this method of manufacturing concrete products using instant demolding, water flowing out from the concrete material collects between the bottom plate of the formwork and closes the gap between the two, which prevents air bubbles from leaving the bottom surface of the concrete. Having no place to escape, the bubbles remain on the surface of the concrete product, and these bubbles sometimes cause numerous large and small bubble marks on the surface of the concrete product.

[Means to solve the problem]

The present invention is a method for manufacturing concrete products developed to solve the above problems, in which water-absorbing paperboard is layered on the bottom plate of a formwork, concrete material is placed in the formwork, and vibration is applied to the concrete material. After applying pressure and leveling the concrete material from above using a finishing machine, the formwork is turned over and demolded, and the water-containing paperboard adhering to the surface of the concrete molded product is removed. It peels off. As the water-absorbing paperboard, dry thick waste paper, thick synthetic fiber paper, etc. are used. In addition, the concrete material used is one with an extremely low water-to-cement ratio and is rough, and in order to improve the surface finish, mortar with a low water-to-cement ratio is sometimes used for the surface layer. The manufacturing method of the present invention is disclosed in Japanese Patent Publication No. 4536305, for example.
Use a concrete product forming machine like the one in the publication.

[For use]

Dry water-absorbent paperboard is layered on the bottom plate of the formwork, and hardened concrete is poured onto it. When the concrete is vibrated, it immediately becomes fluid and compaction progresses. This concrete material can be sufficiently compacted by vibrating it while applying pressure with a finishing plate from above. Due to this vibration and compaction, excess water flowing out from the bottom edge of the concrete material permeates into the water-absorbing paperboard. Also, the air in the concrete material rises and diffuses to the outside.
Air bubbles trapped between the lower surface of the concrete material and the bottom plate either enter the paperboard or are pushed out into the gap between the inner wall of the formwork and the concrete material. Furthermore, after leveling the surface with a finishing machine, the mold is turned over and removed from the mold. When the molded product is removed, wet paperboard is attached to the surface of the molded product. If this paperboard is peeled off, the surface will be clean and free of air bubbles. This results in a concrete product with excellent quality.

【Example】

As an embodiment of the present invention, a method for manufacturing a concrete slab for pavement will be explained based on the drawings. In this embodiment, a concrete block forming machine disclosed in Japanese Patent Publication No. 45-36305 is used. A formwork 2 is placed on the machine stand l, and a water-absorbing paperboard 3 is stacked on the bottom plate 2a of the formwork 2. This paperboard 3 is made of soft recycled paper with a thickness of 2 mm, and is cut into the same size as the bottom plate 2a. First, a small amount of mortar 4 shown in Table 1 is poured and evenly leveled on the paperboard 3. On top of that, the hardened concrete material 5 shown in Table 2 is supplied from the formwork 2 so that it bulges out, and is then vibrated and tightened. Harden. Subsequently, the upper surface of the concrete material 5 is pressed by the finishing plate 6, and then the finishing plate 6 is rotated to level the surface, and the vibration and compaction are completed. Next, the formwork 2 is transferred from the machine 1 to a curing place, immediately turned over and demolded. Finally, after peeling off the water-containing paperboard 3 adhering to the formed concrete pavement board, curing is performed. Although the mortar 4 was used in the above embodiment, only the hardened concrete material 5 may be used. Furthermore, when paper with a particularly rough surface is used as the paperboard 3, it is possible to manufacture a concrete board for pavements that has a rough upper surface and is easy to walk on. Table 2

【effect】

As described above, since the method for manufacturing concrete products according to the present invention involves forming water-absorbing paperboard by stacking it on the bottom plate of a formwork, air bubbles remain on the lower surface of the concrete material, that is, the surface in contact with the paperboard. Never. Therefore, it is possible to produce a clean concrete product with no bubble marks on the surface. l; Machine frame 2; Formwork 2a: Bottom plate 3; Water-absorbing paperboard 4; Mortar 5; Hardened concrete material 6; Finishing board application agent Hisashi Matsumoto

Claims (1)

[Claims] Water-absorbent paperboard was layered on the bottom plate of the formwork, and concrete was poured into the formwork. The concrete was compacted by applying vibrations, and the concrete was then leveled by applying pressure from above using a finishing machine. After that, the formwork is reversed and demolded, and the water-containing paperboard adhering to the surface of the concrete molded product is peeled off.