JPH078134A - Artificial fish reef - Google Patents

Abstract

PURPOSE:To suppress a producing amount of calcium hydroxide to the surface of a fish reef body. CONSTITUTION:Blast furnace granulated slag powder is kneaded into concrete and the kneaded material is formed. As a result, the area of a cement layer formed on the surface is reduced as much as possible by the presence of the blast furnace granulated stag powder and the area attached by white deposition is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial fish reef capable of suppressing the amount of calcium hydroxide produced on the surface of a fish reef body.

[0002]

2. Description of the Related Art In recent years, artificial fish reefs have been actively deposited in the sea, especially on the seabed, for the purpose of so-called collecting, protecting, growing and multiplying aquatic organisms, especially seafood.

In this case, concrete is used as a material suitable for mass production and manufacturing cost, and an artificial fish reef is manufactured by molding it into a shape according to its purpose. The concrete used here is usually It is also known that Portland cement is used.

When this cement hardens, it produces a large amount of calcium hydroxide. On the other hand, in seawater, carbon dioxide gas that dissolves from the atmosphere and water (seawater) containing a large amount of this carbon dioxide gas are natural limestone. Since a large amount of calcium hydrogen carbonate and the like generated by dissolution reacts with the calcium hydroxide generated from the cement, a large amount of calcium compound (mainly calcium carbonate) precipitates and adheres to the surface of the fish reef body. That is, a large amount of white deposits are formed on the surface of the fish reef made of concrete.

As described above, most of the white deposits are calcium carbonate and a large amount of calcium hydroxide is mixed therein, so that the white deposits are highly alkaline. Therefore, in this state, the pH of the surface layer of the fish reef body is high. It is extremely high and forms an environment unsuitable for habitation of living things. Incidentally, normal seawater is in an acidic environment with a pH of around 6, and it is said that organisms die in a highly alkaline environment.

Therefore, in this state, seaweed such as kelp does not propagate on the surface layer of the fish reef body, and abalone, sea urchin and the like that feed on these seaweeds do not approach.

As a means for solving this, it has been made in the past to basically use natural stone, for example, as a fish reef without using the cement as described above.

A method has also already been proposed in which resin caps formed in a shape covering the surface of an artificial fish reef made of concrete are stacked in several layers to cover the fish reef body, and the caps are peeled off year by year. ing.

Further, at the time of molding the fish reef main body, natural stones were buried in the surface of the fish reef main body to prevent the cement layer from being exposed to the outer surface as much as possible.

[0010]

However, in the fish reef made of the above-mentioned natural stone, not only the large amount of natural stone is required, but also the amount of natural stone is naturally limited. In the case of using natural stone, it was also difficult to secure a suitable natural stone, considering that its size is extremely important.

Further, in the case of using the cap body,
The attachment / detachment of the cap body to / from the fish reef body requires a diving work, which is difficult and also unrealistic.

Further, in the case where the natural stone is buried in the surface layer of the fish reef body, this stone does not have to be particularly large, but since it is complicated and difficult to mold, it has been widely used. There was no

[0013]

In order to solve the above-mentioned problems, the artificial fish reef according to the present invention uses granulated blast-furnace slag powder, which produces less calcium hydroxide when being hardened, as a part of cement. Instead, it was kneaded and molded into concrete.

[0014]

In other words, in the artificial fish reef according to the present invention,
By mixing granulated blast furnace slag powder, which produces less calcium hydroxide when hardening, into concrete,
The area of the cement layer formed on the surface is reduced as much as possible, and thus the adhesion area of the white deposit is reduced.

Here, the granulated blast furnace slag powder means slag emitted from an ironmaking blast furnace, impurities in iron ore and ash of coke,
And a melt formed by the reaction of limestone (compositionally, the content of calcium oxide is less than that of cement (which hydrates to calcium hydroxide when hardened)).

[0016]

EXAMPLE Next, an example of an artificial fish reef according to the present invention will be described. The fish reef main body according to the present invention is basically made of concrete. In this case, the granulated blast furnace slag powder is mixed with the concrete. To do.

The granulated blast furnace slag powder used here is 25 to 40% of the amount of cement in concrete, preferably 3%.
About 0% is mixed, and a fine powder (Blaine value of about 6000 cm ² / g) is used as the powder.

The above materials are kneaded and molded by using an ordinary mold. Since the ground granulated blast furnace slag is mixed in the concrete, the ground granulated blast furnace slag also contains the above ground granulated blast furnace slag. The amount of cement that is present and exposed on the surface layer and its area are reduced. Therefore, the white deposits are unlikely to adhere.

In the above description, the blast furnace marine slag powder to be mixed is set to the above-mentioned value because the granulated blast furnace slag basically has no binding property. This is because it is considered brittle. Furthermore, granulated blast furnace slag has its own strength (however, the age must be taken into consideration), so adjusting the amount mixed will not adversely affect the overall strength of the fish reef itself. .

[0020]

As described above, according to the artificial fish reef according to the present invention, since the granulated blast furnace slag powder is kneaded into the concrete and molded, it is formed on the surface due to the presence of the granulated blast furnace slag powder. It is possible to reduce the area of the cement layer as much as possible, and thus to reduce the area of adhesion of the white deposits.

Claims (3)

[Claims] 1. An artificial fish reef characterized by being formed by kneading granulated blast furnace slag powder into concrete. 2. The artificial fish reef according to claim 1, wherein the granulated blast furnace slag powder is 25 to 40% of the amount of cement in concrete. 3. The artificial fish reef according to claim 1, wherein the granulated blast furnace slag powder is a fine powder.