JPH0441884B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is applicable to forming friction-increasing parts on concrete piles, and forming decorative patterns on the surfaces of concrete columns, beams, gateposts, poles, etc. It relates to the manufacturing method of concrete products and belongs to the industrial field that deals with concrete products made by centrifugal forming.

(Prior art) Conventionally, after the surface of a concrete product is in a semi-hardened state, a part of the cement mortar on the surface is removed,
A washing method is known that exposes the aggregate on the surface.

This cleaning method involves applying a hardening retardant to the inner surface of the formwork in which concrete is to be formed, pouring the concrete, and after removing the mold, the semi-hardened cement mortar on the cement surface is washed out with water to expose the aggregate. A method is adopted in which the surface of concrete after hardening is dissolved and removed using an acid such as hydrochloric acid or sulfuric acid.

It is possible to use these washing methods to expose aggregate at desired locations on the surface of concrete piles. In other words, the strength of a pile buried underground increases as the frictional force with the stratum increases. However, geological formations are made up of multiple layers with different properties, and while it is desirable to increase the friction with layers such as gravel, it is not desirable to increase the friction with soft layers. , it is necessary to selectively expose aggregate at desired locations in the concrete layer.

(Problem to be Solved by the Invention) However, when manufacturing concrete products by centrifugal molding, according to the former of the conventional washing methods, the curing retardant applied to the formwork is washed away by the inner surface of the formwork due to centrifugal force. There is a problem that it is difficult to accurately form the desired aggregate exposed surface because of the diffusion.

Furthermore, among the conventional washing methods, the latter method is dangerous due to the handling of acid, requires specialized workers, and even professional workers can shape the concrete surface into the desired shape based on the use of acid. There are problems in that it is not easy to dissolve accurately and the working efficiency is also not good.

(Means for Solving the Problems) The basic purpose of the present invention is to solve the above problems, and the present invention is a method for manufacturing concrete products that can accurately and quickly form an exposed surface of aggregate into a desired shape. It provides:

That is, in this invention, concrete is poured into a centrifugal molding form with a predetermined shape of hardening retarder paper pasted on the inner wall, a concrete product is centrifugally molded by a conventional method, and then concrete is applied to the hardening retarder paper. This method is characterized by exposing the aggregate by washing out the surface of the concrete product in contact with it and removing the cement mortar near the surface.

The hardening retarder paper can be coated with or impregnated with both a release agent and a segment hardening retarder or only a cement hardening retarder, or can be coated with or impregnated with other chemicals if desired. It is also possible to use an impregnated one.

The cement hardening retarders used here include lignins, sugar oxides such as gluconic acid,
Examples include sugars such as sugar and fluorine compounds such as magnesium silicofluoride.

This curing retarder paper is cut into a predetermined shape according to the shape to be added to the surface of the concrete product. The predetermined shape can be arbitrarily determined, and it can also be shaped to represent famous landscapes or famous figures, such as forming patterns on the surface of concrete products, and can also be shaped to represent famous landscapes or famous figures, etc. can also be expressed arbitrarily.

For example, when cutting curing retarder paper into a predetermined shape, an NC-controlled (numerically controlled) cutting machine can be used to easily produce curing retarder paper of the same shape, and it can also be cut into various shapes. It is also possible to efficiently cut curing retarder paper.

An adhesive layer made of adhesive, pressure-sensitive adhesive, etc. is provided on the surface of the curing retarder paper formed into a predetermined shape, and the paper is pasted to a predetermined location on the inner wall of a centrifugal molding form via this adhesive layer. For example, taking into account the depth of the piles to be driven into the ground and the geological condition, aggregate is attached to the inner surface of the formwork in accordance with the location of the concrete pile where it is desired to be exposed. When adding a pattern to the surface of a concrete product, the pattern is attached to the inner surface of the formwork so as to match the part of the concrete product to be patterned.

This centrifugal forming form is not limited to a specific shape, and can be applied to various forming forms used for manufacturing concrete products of various shapes to be formed. Using a formwork with this hardening retardant paper attached to the inner wall, the concrete content is centrifugally formed, compacted, and hardened. After demolding, the cement mortar on the surface of the concrete product can be washed out and removed by simple and inexpensive washing with water. It is also possible to use solutions in which various chemical solutions are dissolved, if desired.

Note that the depth of the above-mentioned washing out can be freely set by adjusting the amount and type of the chemical applied to and impregnated into the hardening retardant paper, the hardening time of the concrete, etc.

(Operation of the invention) That is, according to the present invention, the hardening retarder paper attached to the inner wall of the centrifugal molding form comes into contact with the surface of the concrete where the aggregate is to be exposed, and the hardening retarder paper is coated or impregnated. The chemical applied penetrates into the concrete surface. This agent contains either a release agent or a concrete retarder, or only a cement retarder, and inhibits the hardening of the concrete in contact with the retarder paper.

After compacting with a centrifugal molding machine, the concrete is then cured at room temperature or by steam curing, and after being removed from the mold, the concrete surface where the hardening retardant paper contacts is washed away, since the concrete in this area is in a semi-hardened state. Cement and sand are easily washed out and removed, and the unevenness of the aggregate is formed on the surface of the concrete product precisely along the shape of the hardening retarder paper, dramatically improving the coefficient of friction.

Concrete is a mixture of aggregates with various particle sizes, and due to the centrifugal force during centrifugal forming, large-diameter aggregates, that is, coarse aggregates, are scattered more on the surface side, making the unevenness more noticeable. , the friction coefficient is significantly improved, and the appearance is also improved.

Therefore, even when it is desired to add a pattern to the surface of a concrete product, a highly decorative pattern can be accurately formed using hardening retarder paper.

(Example) An example of the present invention will be described below based on FIGS. 1 to 4.

The curing retarder paper 1 used in this example has a multilayer structure as shown in FIG.

That is, a waterproof protective layer 3 is provided on the other surface (lower layer in the figure) of the base paper 2, which has a chemical layer 1a coated with a release agent and a cement hardening retardant, and the lower layer of this protective layer 3 Then add adhesive layer 4
is formed, and a separator 5 is formed on the surface of the adhesive image layer 4.
is installed.

The hardening retardant paper 1 is cut into a predetermined shape corresponding to the shape desired to be added to the surface of a concrete pile, and then used to form the inner wall 6a of a centrifugal shaping form 6 for shaping a cylindrical concrete product. Curing retarder paper 1 with separator 5 peeled off at a predetermined location
is pasted through the adhesive layer 4 (Fig. 2).

With the chemical layer 1a of the hardening retardant paper 1 exposed inward, cement and
Concrete 7 mixed with aggregate and water is injected and centrifugally formed by rotating the form 6 using a centrifugal forming machine (not shown) (FIG. 3). At this time, it is also possible to increase the strength by arranging reinforcing bars as necessary.

A cylindrical concrete pile 8 is obtained by this centrifugal forming machine.

Next, at least the part of the concrete pile 8 that was in contact with the hardening retarder paper 1 is washed with water to remove the semi-hardened cement mortar on the surface part. Next, on the removed surface portion, an uneven portion having the same shape as the hardening retardant paper 1 is formed by washing out the cement mortar, and relatively large-diameter coarse aggregate is exposed in an orderly manner to form an aggregate exposed surface 9. is formed.

This concrete pile 8 is embedded in the ground, and the exposed aggregate surface 9 comes into contact with a desired stratum 10, increasing friction and improving strength.

FIG. 5 shows another example, in which curing retarder paper is shaped into a predetermined shape and concrete product 1 is prepared.
A pattern 12 is formed on the surface of 1.

In this example, curing retarder paper is cut into a predetermined shape corresponding to the pattern desired to be added to the surface of the concrete product 11, and washed out in the same manner as in the previous example.
It forms the On the surface where the aggregate is exposed by washing out, relatively large-diameter coarse aggregate is exposed in an orderly manner, and the exposure of this aggregate has the effect of significantly improving decorative hardening.

The shape of these curing retarder papers is arbitrary and can be determined as appropriate to suit the pattern desired to be expressed on the surface of the concrete product. It is also possible to represent the pattern of

Further, the shape and use of the concrete product to which the pattern is added are not particularly limited, and the present invention can be applied to various concrete products formed by centrifugal molding.

In addition, in these examples, a set retarder paper coated with both a release agent and a cement set retarder on the surface was used, but a set retarder paper containing only a cement set retarder may also be used. Any substance that delays the hardening of cement through the action of the drug may be used. It is also possible to impregnate the curing retarder paper with the agent. Furthermore, in the above two embodiments, the curing retarder paper was provided with an adhesive layer 4 on one side of the base paper, and a separator 5 was further provided on the surface thereof, but it is necessary to provide an adhesive layer and a separator as the curing retarder paper. This is not necessarily the case, and it is also possible to use the curing retarder paper shown in FIG. 6 and apply an adhesive or adhesive to the curing retarder paper or the mold when pasting it to the mold. Note that 13 in the figure is a chemical layer having both a release agent and a cement hardening retardant applied to its surface.

(Effects of the Invention) As explained above, according to the present invention, concrete is poured into a formwork for centrifugal molding with curing retarder paper of a predetermined shape pasted on the inner wall, and the concrete product is centrifuged in a conventional manner. After forming, the surface of the concrete product in contact with the hardening retarder paper is washed out to remove cement mortar.
By appropriately determining the position or shape of the hardening retardant paper, it is possible to efficiently provide an uneven aggregate exposed surface on the surface of the concrete product, and the coarse aggregate is exposed in an orderly and close manner due to the centrifugal effect. It has the effect of being extremely beautiful and having excellent decorative effects.

[Brief explanation of drawings]

Fig. 1 is an enlarged cross-sectional view of a release paper used in an embodiment of the present invention, Fig. 2 is a partial sectional view of the formwork, and Fig. 3 is a state in which concrete is poured into the formwork and centrifugally formed. FIG. 4 is a cross-sectional view showing the state of use of a concrete product similarly obtained by implementing the present invention, FIG. 5 is a perspective view of a concrete product obtained by another example, and FIG. 6 is a hardened concrete product. FIG. 7 is an enlarged cross-sectional view showing a modified example of retardant paper. 1... Curing retarder paper, 1a, 13... Drug layer,
3... Protective layer, 6... Formwork, 6a... Inner wall, 8...
...Concrete pile, 9...Aggregate exposed surface, 11...
...Concrete products, 12... Decorative patterns.

Claims (1)

[Scope of Claims] 1. Concrete is poured into a centrifugal molding form with a predetermined shape of hardening retarder paper pasted on the inner wall, and after centrifugally molding a concrete product by a conventional method, the hardening retarder paper is A method for producing a concrete product having a washed-out portion on the surface, which comprises washing out the surface of the concrete product that has come into contact with the concrete product and removing cement mortar near the surface to expose aggregate. 2. The hardening retarder paper has a surface coated with or impregnated with both a release agent and a cement hardening retarder, or only a cement hardening retarder. A manufacturing method for concrete products having parts.