Coating material for underwater structure, underwater structure and method for producing underwater structure with coating material

Abstract

[Project] The objective is to provide a covering material for underwater structures that can supply nutrients to seaweed for a longer period even when using underwater structures. [Solution] The covering material for underwater structures comprises ferrous fulvate (2-valent) produced by reacting ferrous sulfate with fulvic acid, and at least a portion is covered on the outer surface of an underwater structure (e.g., artificial grass (1)) installed underwater. By doing so, nutrients can be supplied to the seaweed for a longer period even when using the underwater structure.

Description

Technology Field

[0001] The present invention relates to a covering material for an underwater structure, an underwater structure, and the manufacture of an underwater structure with the covering material attached, relating to an underwater structure in which at least a part thereof is installed underwater. Background Technology

[0002] Recently, in coastal areas, the decrease in seaweed such as algae has led to the progression of rocky-shore denudation. This is because, although iron fulvate, which is generated in the humus soil of forests, used to flow in from rivers in the past, its amount has decreased recently, resulting in a shortage of nutrients necessary for seaweed. Patent Document 1 discloses a water environment conservation material in which iron fulvate leaches out when submerged in water by containing a divalent iron-containing material and a humus-containing material. Prior art literature

[0003] Japanese Patent Publication No. 2006-81457 The problem to be solved

[0004] However, underwater structures such as wave-dissipating blocks and breakwaters exist in the water, and concrete is frequently used as a component of these underwater structures. Calcium hydroxide contained in concrete reacts with iron fulvate in the water, causing the iron fulvate to become trivalent, which does not contribute to the growth of seaweed. As a result, as long as underwater structures are exposed and exist in the water, it is difficult to suppress the progression of the seaweed erosion phenomenon even when using water environment conservation materials such as those described in Patent Document 1.

[0005] Therefore, the present invention aims to provide a covering material for an underwater structure and an underwater structure covered with the covering material, which can supply nutrients to seaweed for a longer period even when using an underwater structure including concrete, etc. means of solving the problem

[0006] The coating material for an underwater structure according to the present invention comprises ferrous fulvate (divalent) produced by reacting ferrous sulfate with fulvic acid, and at least a portion of it is coated on the outer surface of an underwater structure installed underwater.

[0007] The underwater structure of the present invention comprises a main body and a coating material provided on the outer surface of the main body, comprising ferrous sulfate (divalent) produced by reacting ferrous sulfate with fulvic acid.

[0008] The method for manufacturing an underwater structure with a coating material attached according to the present invention is characterized by forming an underwater structure to be installed underwater in at least a portion thereof, and coating the outer surface of the underwater structure with a coating material comprising ferrous sulfate (divalent) produced by reacting ferrous sulfate with fulvic acid. Effects of the invention

[0009] According to the present invention, nutrients to seaweed can be supplied for a longer period even when using an underwater structure. Brief explanation of the drawing

[0010] FIG. 1 is a perspective view of an artificial reef according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of an artificial grass of one embodiment of the present invention. FIG. 3 is an explanatory diagram of the manufacturing process of an artificial grass according to one embodiment of the present invention. FIG. 4 is an explanatory diagram of the function of an artificial grass of one embodiment of the present invention. FIG. 5 is an explanatory diagram of a seawall and a breakwater block of one embodiment of the present invention. FIG. 6 is a side view of a quay wall and a sofa block of one embodiment of the present invention. FIG. 7 is a cross-sectional view of a quay wall of one embodiment of the present invention. FIG. 8 is an explanatory diagram and cross-sectional view of a sofa block of one embodiment of the present invention. FIG. 9 is a side view of a breakwater and a wave-dissipating block of one embodiment of the present invention. FIG. 10 is a cross-sectional view of a breakwater according to one embodiment of the present invention. Specific details for implementing the invention

[0011] One embodiment of the present invention will be described in detail below with reference to the drawings. The configurations, shapes, components, etc. described below are examples for illustrative purposes and may be appropriately modified in accordance with the specifications of the underwater structure, covering material, and underwater fertilizer material. In the following, the same reference numerals are used for corresponding elements in all drawings, and redundant descriptions are omitted.

[0012] First, with reference to FIGS. 1 and 2, the composition of an artificial reef (1) as an example of an underwater structure will be described. In addition, other underwater structures include caissons, such as wave-dissipating blocks, breakwaters, seawalls, or parts of bridges as shown in FIGS. 5 to 10, in which at least a part of the outer surface is placed and installed underwater, and are generally manufactured including concrete or steel.

[0013] The artificial grass (1) is formed by including a roughly spherical main body (2) having an internal cavity (2a) formed inside, and a fertilizer material (hereinafter referred to as "underwater fertilizer material (3)") that is filled into a retaining part (4) formed in the main body (2) and installed underwater. At least one upper opening (5) that penetrates to the internal cavity (2a) is formed in the upper part (2b) of the main body (2). Additionally, a plurality of side openings (6) that penetrate to the internal cavity (2a) are formed in the side part (2c) of the main body (2). The artificial grass (1) is installed so that the bottom part (2d) of the main body (2) is in contact with the seabed. Furthermore, the shape of the main body (2) may be such that it can be installed stably on the seabed, and may be an irregular shape that imitates a rock.

[0014] In FIG. 2, the main body (2) is formed to include a base (7) on the side of the internal cavity (2a) and an outer part (8) formed on the outside of the base (7). The base (7) is formed of dense concrete containing cement, gravel, sand, diatomaceous earth, water-reducing agent, etc. By this, the base (7) can maintain strength for a long time even in seawater. The outer part (8) contains cement, gravel, sand, diatomaceous earth, water-reducing agent, etc. and has a number of uneven shapes or pores formed therein. The outer surface of the main body (2), including the upper part (2b), side part (2c), bottom part (2d), and interior (2e) (the surface of the base (7) forming the internal cavity (2a)), is covered by a coating material (9) containing iron fulvate (in a divalent iron state) by coating, etc. As for ferrous fulvate (in the divalent iron state), it will be described later. In this way, the main body (2) is formed including concrete, and at least the outer surface (upper part (2b), side part (2c)) of the main body (2) has a number of irregular shapes or pores. By having a number of irregular shapes or pores on the outer surface of the main body (2), seaweeds can easily attach to and grow on the outer surface of the artificial grass (1). Furthermore, the irregular shapes or pores on the outer surface of the main body (2) are freely designed according to the type of seaweed that attaches and grows.

[0015] In FIG. 2, the retaining portion (4) is formed by penetrating from the outer surface (side portion (2c)) of the main body portion (2) through the outer portion (8) and base (7) to the internal cavity (2a). The retaining portion (4) is filled with an underwater fertilizer (3). The underwater fertilizer (3) is composed of at least one of cement, sand, gravel, silicon, diatomite, granular stone (e.g., diameter 3 mm to 5 mm) and iron fulvate (in a divalent iron state). As for the stone included in the underwater fertilizer (3), it is preferable to include elements such as magnesium, barium, strontium, and rubidium. The hydrogen ion index (pH) of the underwater fertilizer (3) is less than 8, and 7.7 to 7.9 is most preferable. The underwater fertilizer (3) can be attached in a solid state to the inside of the maintenance part (4) or the outer surface of the main body part (2) by means of cement. In addition, the underwater fertilizer (3) can supply minerals, which are components necessary for the growth of seaweed, etc., in small amounts over a long period of time from within. Furthermore, by filling the maintenance part (4) with the underwater fertilizer (3), minerals, etc. can be supplied appropriately and stably.

[0016] Additionally, the underwater fertilizer (3) may be exposed to at least one of the internal cavity (2a) and the outer surface of the main body (2). Furthermore, the underwater fertilizer (3) does not necessarily need to be completely filled into the retaining part (4), and may be filled into a part of the inner wall of the retaining part (4). Additionally, it may be configured such that a groove is formed on the outer surface (upper part (2b), side part (2c)) of the main body (2) and the underwater fertilizer (3) is attached to the groove. Thus, the artificial grass (1) may include the main body (2) and the underwater fertilizer (3), which includes cement, iron sulfide, and silicone, attached to at least a part of the main body (2).

[0017] In FIGS. 1 and 2, the size of the artificial reef (1) ranges from 20 cm to 2 m in height and is appropriately changed according to the installation location and the type of seaweed or fish to be raised. For example, in the case of an artificial reef (1) with a height of 70 cm, the thickness of the main body (2) is 15 cm when combining the base (7) and the outer part (8), and the weight is 170 kg. Additionally, the upper opening (5) has a diameter of 30 cm, the side opening has a diameter of 15 cm to 25 cm, and the support part (4) has a diameter of 10 cm to 15 cm. The upper opening (5) and the side opening (6) are preferably sized so that fish inhabiting the location where the artificial reef (1) is installed can freely move between the outside and the inside cavity (2a). Additionally, the weight (thickness of the main body (2)) is preferably such that the artificial reef (1) does not move due to large waves such as typhoons.

[0018] Next, with reference to FIG. 3, the manufacturing process of the artificial candle (1) will be described. First, fresh concrete (unhardened concrete) containing a predetermined material that becomes the base (7) is poured into a mold to form the base (7) (Fig. 3(a)). The mold has a shape formed in advance that becomes an internal cavity (2a), an upper opening (5), and a side opening (6). Next, the outer surface of the base (7) is processed to form an outer part (8) having a plurality of uneven shapes or pores (Fig. 3(b)). Additionally, the outer part (8) may be formed by processing fresh concrete additionally applied to the outer surface of the base (7).

[0019] Next, a retaining portion (4) that penetrates to the internal cavity (2a) is formed on the side portion (2c) of the main body portion (2) (Fig. 3(c)). The hole that becomes the retaining portion (4) is formed using a core drill or the like. Additionally, the retaining portion (4) does not necessarily have to be a shape that penetrates to the internal cavity (2a); it may be a concave portion or a groove formed on the surface (upper portion (2b), side portion (2c), bottom portion (2d), interior (2e)) of the main body portion (2). Furthermore, the location and number of the retaining portions (4) can be appropriately designed. Additionally, the retaining portion (4) may be formed on the upper portion (2b) of the main body portion (2). Also, the retaining portion (4) may be formed during the creation of the base (7), just like the upper opening (5) and the side opening (6).

[0020] Next, a coating material (9) is applied to the entire outer surface (upper (2b), side (2c), bottom (2d), and inner (2e)) of the main body (2), including the inner wall of the retaining part (4), upper opening (5), and side opening (6) formed in the main body (2) (Fig. 3(d)). The coating material (9) is not limited to being applied by coating, but may cover the main body (2). As will be described later, the coating material (9) contains iron sulfide, and may be applied to the main body (2) using an air gun or the like, or may be applied by immersing the main body (2) in a liquid containing iron sulfide contained in a container (tank). The iron sulfide applied to the outer surface of the main body (2) (outer part (8)) penetrates into the concrete and forms an iron sulfide-containing layer, thereby preventing the leakage of calcium hydroxide into the water.

[0021] Next, water is added to a predetermined material that becomes an underwater fertilizer (3) to form a paste. Then, the paste is filled and attached to a retaining part (4), etc., to form a predetermined shape (Fig. 4(e)). After that, by drying, a solid underwater fertilizer (3) is formed. In this way, the underwater fertilizer (3) of the present embodiment can be easily formed into various shapes by adding water to form a paste and filling and attaching it to a predetermined location. In addition, after drying, it becomes solid, allowing the contained minerals, etc., to be supplied to the water in small amounts over a long period of time.

[0022] Next, with reference to FIG. 4, the function of the artificial grass (1) will be explained. FIG. 4 illustrates an artificial grass (1) installed on the seabed (10). Minerals are supplied from the underwater fertilizer (3) filled in the maintenance part (4) of the artificial grass (1) to the seawater (11) outside the artificial grass (1) (arrow (a)) and inside the cavity (2a) (arrow (b)). The water flow entering the inside cavity (2a) from the side opening (6A) and side opening (6B) of the artificial grass (1) (arrow (c)) flows inside the inside cavity (2a) (arrow (d)) and exits to the outside of the artificial grass (1) through the top opening (5) (arrow (e)). By this, minerals supplied from the underwater fertilizer (3) to the internal cavity (2a) are supplied to the far side of the artificial grass (1).

[0023] In this way, the internal cavity (2a) is formed inside the main body (2) and is connected to the outside of the main body (2) through the upper opening (5) and the side openings (6A, 6B). Additionally, it is preferable to position the retaining part (4) above any one of the multiple side openings (6A, 6B). By doing so, minerals leached into the internal cavity (2a) from the underwater fertilizer (3) filled in the retaining part (4) can be efficiently supplied to the outside through the upper opening (5).

[0024] In addition, the side openings (6A, 6B) and the upper opening (5) can disperse the force that moves the artificial grass (1) laterally by allowing large waves, which are generated by typhoons or the like and surge onto the side (2c) of the artificial grass (1), to flow out from the side openings (6A, 6B) to the upper opening (5). By doing so, the artificial grass (1) installed on sandy ground or gravel ground can be prevented from moving away from the installation site, tipping over, or being buried in sand, thereby maintaining a stable state. Furthermore, by attaching the underwater fertilizer (3) to the maintenance part (4), the underwater fertilizer (3) can be prevented from being scattered by large waves.

[0025] In this way, seaweed and other marine algae grow on the outer surface (upper part (2b), side part (2c)) of the artificial reef (1) or on the seabed (10) surrounding the artificial reef (1) through components such as minerals supplied from the underwater fertilizer (3). That is, the artificial reef (1) to which the underwater fertilizer (3) is attached is an underwater fertilizer structure that supplies minerals and other substances necessary for the cultivation of seaweed or coral underwater. In addition, the underwater structure may be a wave-dissipating block installed underwater or on the coast or riverbank, in addition to the artificial reef (1).

[0026] Here, examples in which the underwater structure is not an artificial reef (1) are described. Referring to FIGS. 5 through FIGS. 8, the case in which the underwater structure is a seawall (12) and / or a wave-dissipating block (13) is described, and referring to FIGS. 9 and 10, the case in which the underwater structure is a breakwater (14) and / or a wave-dissipating block (13) is described.

[0027] As illustrated in FIGS. 5 and 6, at least a portion of the underwater structure, the quay wall (12) and the wave-dissipating block (13), is installed underwater. As shown in FIG. 7, since the quay wall (12) is configured to cover the coast, the main body (2) is installed at a portion of the boundary between the land and the coast. Accordingly, a covering material (9) is applied to the outer surface of at least the portion of the main body (2) of the quay wall (12) that comes into contact with seawater. Of course, the covering material (9) may be applied to the entire outer surface of the quay wall (12). Additionally, one or more underwater fertilizers (3) may be placed, such as by providing a retaining portion (4) on a portion of the outer surface of the quay wall (12) that comes into contact with seawater. Furthermore, the covering material (9) may also be applied between the main body (2) of the quay wall (12) and the seabed (10).

[0028] Additionally, FIG. 8(a) is a wave-dissipating block (13), and FIG. 8(b) is a schematic cross-sectional view of the wave-dissipating block (13) viewed from direction A of FIG. 8(a). As shown in FIG. 8(b), a covering material (9) is covered on the outer surface of the main body (2) of the wave-dissipating block (13), at least in the part in contact with the sea, and may be covered over the entire outer surface. One or more underwater fertilizers (3) may be arranged, such as by providing a retaining part (4) on a part of the outer surface of the wave-dissipating block (13) that is in contact with seawater.

[0029] In addition, when the underwater structure is a breakwater (14), as shown in FIG. 9, at least a portion of the underwater structure, the breakwater (14) and the wave-dissipating block (13), are installed underwater. Since the breakwater (14) is installed away from the coast, a foundation stone (14c) is provided at the bottom above the seabed (10), a caisson (14b) is installed on top of the foundation stone (14c), and concrete (14a) is installed on top. The covering material (9) is covered at least on the outer surface of the caisson (14b) and the foundation stone (14c) that is in contact with the coast, but it may be covered over the entire outer surface. Of course, the covering material (9) may also be covered over at least a portion of the outer surface of the concrete (14a). One or more underwater fertilizers (3) can be arranged, such as by providing a maintenance part (4) on a part of the outer surface of a caisson (14b) that is in contact with seawater, for example, by the breakwater (14).

[0030] Next, we will explain the iron fulvate (in the divalent iron state) included in the covering material (9) and the underwater fertilizer (3). As previously mentioned, in coastal areas, seaweed is decreasing and the phenomenon of coastal erosion is progressing. Previously, iron fulvate generated in the humus soil of forests was flowing in from rivers, but recently, the amount has decreased. Therefore, we want to supply fulvate to the seawater, but ordinary divalent iron fulvate (divalent iron ions) is easily oxidized by oxygen in the water, changing into trivalent iron fulvate (trivalent iron ions) and immediately forming and sinking as granular iron, making it impossible for organisms to consume.

[0031] In addition, divalent iron fulvate (divalent iron ions) reacts with calcium hydroxide contained in concrete to become trivalent iron fulvate (trivalent iron ions). In this case, calcium hydroxide in concrete, which is frequently used in underwater structures, also leaches out, which can degrade the durability of the concrete. As such, installing concrete exposed underwater is not desirable for the marine environment because it accelerates the deterioration of the concrete, along with promoting the phenomenon of seaweed erosion that transforms divalent iron fulvate (divalent iron ions) into trivalent iron fulvate (trivalent iron ions) underwater.

[0032] Accordingly, the present invention provides a covering material (9) and an underwater fertilizer (3) containing fulvic acid that can maintain a divalent state for a longer period even underwater, and a structure that prevents the deterioration of concrete.

[0033] First, here we will explain fulvic acid that can maintain a divalent state even in water. Iron fulvate (in a divalent iron state) is preferably prepared by dissolving ferrous sulfate with a pH of 4 or lower and fulvic acid in fresh water, respectively, and mixing them. In other words, it is desirable to always convert to iron fulvate in an acidic state. By using ferrous sulfate with a pH of 4 or lower, it becomes difficult for iron fulvate to change into trivalent iron for a long period of time even when it comes into contact with water or seawater. It is preferable to incorporate at least 0.001 to 0.1% by weight of fulvic acid relative to ferrous sulfate.

[0034] The covering material (9) is prepared by dissolving ferrous sulfate and fulvic acid in fresh water using the method described above, and is applied to the entire main body (2) by spraying or the like (or coating). In the case of an underwater structure other than the artificial grass (1) (e.g., wave-dissipating blocks, breakwaters, seawalls, etc.), the covering is applied to at least the outer surface of the underwater structure that comes into contact with water. Of course, the entire outer surface may also be covered.

[0035] In this way, by covering the entire outer surface with a covering material (9) as an outer surface treatment of the underwater structure, an iron sulfide-containing layer is formed, thereby suppressing the leaching of calcium hydroxide in the concrete contained in the underwater structure into the water, and preventing the decrease in the strength of the underwater structure. In addition, since it is also possible to prevent the oxidation of iron fulvate by calcium hydroxide in the concrete, iron fulvate in a divalent iron state can be supplied into the water for a long period of time.

[0036] In addition, the role of the covering material (9) is to promote the growth of seaweed by supplying iron fulvate, which is part of its composition, into the water. At the same time, by continuously covering the outer surface of the underwater structure over a long period, it also prevents calcium hydroxide of the concrete contained in the underwater structure from leaking into the water. Therefore, the covering material (9) has the role of leaching into the water and the role of remaining on the outer surface of the underwater structure. Therefore, in order to continuously perform these two roles over a long period, a thickness of at least 3 mm is required, and preferably 5 mm to 10 mm. However, if the outer surface of the main body (2) has irregularities, the thickness of the covering material (9) changes according to the shape of the irregularities.

[0037] Additionally, the underwater fertilizer (3) can be prepared by mixing an appropriate amount of cement, sand, small gravel, micro silica, natural ore, rock salt, etc. with seawater, and in the mixture, preferably by dissolving ferrous sulfate and fulvic acid, each with a pH of 4 or lower, in fresh water, and then mixing the resulting iron fulvate (in a divalent iron state) by combining and reacting them. Natural ore or rock salt, etc., may be added not only during the preparation of the underwater fertilizer (3), but also during the preparation of the covering material (9). By doing this, even when the underwater fertilizer (3) is not used, nutrients consisting of natural ore or rock salt, etc., are released into the water from the covering material (9), thereby promoting the growth of seaweed.

[0038] In addition, by forming a covering material (9) containing iron sulfide, etc., on the outer surface (upper (2b), side (2c), bottom (2d), and inner (2e)) of the main body (2), the hydrogen ion index (pH) near the outer surface where the artificial reef (1) comes into contact with seawater can be adjusted to an environment suitable for the growth of seaweed. For example, the hydrogen ion index (pH) near the outer surface where the artificial reef (1) comes into contact with the coast is preferably 7.8 to 8.4, which is the same as that of seawater.

[0039] Furthermore, although the descriptions so far have primarily focused on underwater structures installed in seawater, the use of underwater structures is increasing, such as when riverbeds and riverbanks are reinforced with concrete during river revetment construction due to river flooding caused by heavy rain disasters. Since there is a possibility that such underwater structures installed in water other than the sea, such as rivers, may also affect the sea due to flooding, the present invention may be applied. Industrial applicability

[0040] The present invention provides a covering material for underwater structures and an underwater structure covered with the covering material for stably supplying components necessary for the cultivation of seaweed, etc. Explanation of the symbols

[0041] 1: Artificial grass (underwater fertilization structure) 2: Main body 2a: Internal cavity 2b: Top (outer surface) 2c: Side (external) 3: Underwater fertilizer 4: Maintenance section 5: Upper opening 6, 6A, 6B: Lateral opening

Claims

Claim 1 An underwater structure comprising a main body and a covering material provided on the outer surface of the main body, the covering material comprising ferrous sulfate (divalent) produced by reacting ferrous sulfate with ferrous acid, wherein the main body comprises concrete and the covering material covers the entire outer surface of the main body. Claim 2 An underwater structure according to claim 1, characterized in that the coating material is sprayed and applied to the outer surface of the main body. Claim 3 An underwater structure according to claim 1, characterized in that the thickness of the covering material is 3 to 10 mm. Claim 4 A method for manufacturing an underwater structure with a coating attached, characterized by forming a main body portion including concrete and covering the entire outer surface of the main body portion with a coating material containing at least ferrous sulfate (divalent) produced by reacting ferrous sulfate with fulvic acid. Claim 5 delete

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