JPS6089304A - Manufacture of concrete product having small projection pattern - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a concrete product with a pattern of small protrusions.

Conventionally, concrete products with uneven patterns have been formed using flexible formwork with uneven patterns, but air bubbles in the concave parts of the formwork often fail to escape, leaving small holes in the convex parts of the concrete products. However, it was difficult to obtain the expected uneven pattern.

In particular, as shown in Figure 1, the surface of concrete poles for preventing stickers is covered with many small wart-like protrusions, and the shape of these small protrusions has a great effect on the anti-sticking effect, so the formwork It was important not only from an aesthetic point of view but also from a performance point of view to form the mold accurately according to the pattern. The object of the present invention is to improve the drawbacks of the prior art as described above.

Hereinafter, embodiments of the method of the present invention will be described in detail with reference to the drawings. Figure 1 is a side view of a concrete pole 1 for preventing pasting.A pasting prevention surface 2 is simultaneously formed on the above-ground part of the pole. 3 are provided in large numbers. As shown in the cross-sectional view of FIG. 3, this molding is carried out by filling concrete 7 into a flexible inner mold 5 which has a number of well-defined recesses 6 on the inside of a cylindrical formwork (not shown). , molded by centrifugal rotation. However, since the recesses 6 are independent recesses, the bubbles 4 do not come out and the protrusions 3 on the product surface do not come out even after demolding.
A small hole remains at the top of the protrusion 3, impeding the pasting prevention effect, and the edge 8 of the small hole at the top of the protrusion 3 is sharp, which may cause damage to human skin.

Of course, the beauty is also inferior. In order to solve this problem, we conducted molding experiments with various changes in concrete mix, workability, rotation speed and time of centrifugal molding, initial speed, medium speed, high speed rotation speed, time, speed change method, etc. I couldn't reach a solution. The present invention solves this problem by applying a wetting agent 6 such as a neutral surfactant to the inner mold 5 in advance. After coating or spraying a neutral surfactant aqueous solution on the surface of the inner mold 5 to form a wetting agent layer 9 on the uneven pattern surface of the inner mold 5, the concrete 7 is placed on the inner mold 5 as shown in cross-sectional view f21 in FIG. By centrifugally molding the wetting agent layer 9 on the surface of the recess 6 of the inner mold 5.
However, water from the concrete 7 is drawn in, the air bubbles 4 are expelled, and the recesses 6 are filled to form the protrusions 3 accurately. In this illustrated embodiment, the wetting agent 9 is a 10% commercially available neutral detergent based on a nonionic surfactant.
I used one coated with an aqueous solution, but any material that does not have any negative effects on the concrete may be used. Negative effects on concrete include poor curing that occurs when the concentration is high and the wetting agent layer is thick, acidic substances such as calcium chloride, and fatty acid lime formation such as soap, and as a result, the surface of the protrusions 3 becomes powdery. These problems include blowing, bubbles 3, difficulty in releasing from the inner mold 5, chipping of the protrusions 3, and deterioration of abrasion resistance and weather resistance.

The present invention has been described above with respect to a compaction method using centrifugal force, but it is even more effective when vibration compaction is used instead of compaction using centrifugal force. If the vibrator is inserted into the concrete 7, there is a risk that the vibrator will hit the formwork 5 and damage it, and the vibrator cannot be attached directly to the formwork 5, Even if a strong formwork is installed or a vibrator is installed, the bubbles 4 cannot be removed because they only work indirectly.

Therefore, according to the manufacturing method of the present invention, in which the wetting agent 6 is applied to the formwork 5, the formwork 5 is wrapped in a stronger formwork, and the formwork is vibrated to compact it, even weak indirect vibration is sufficient. Can be molded.

In addition, if the protrusions 3 are not independent but continuous in a linear or planar shape, it can be formed by a normal concrete compaction method without using a wetting agent as in the present invention. I can do it.

As described above, according to the present invention, it is possible to provide a concrete product that overcomes the drawbacks of conventional methods.

[Brief explanation of the drawing]

Figure 1 is a side view of a general concrete pole for preventing pasting, Figure 2 is an enlarged side view of its pasting prevention surface, and Figure 3 is:
FIG. 1 is a sectional view of a concrete product having a pattern of small protrusions according to the present invention. 1... Concrete ball for pasting prevention 2... Pasting prevention surface 3... Protrusion 4... Air bubble 5... Flexible formwork

Claims (1)

[Claims] A concrete product with a small protrusion pattern characterized by applying a wetting agent such as a neutral surfactant liquid to the surface of a flexible formwork having many small recesses, and then pouring concrete and compacting it. Production method.