JPH09227202A - Underwater block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater block high in strength by forming the block of a concrete molded product in which almost spherical electrical furnace oxidized slag particulates having fine ruggedness on the surface are dispersed as fine aggregates into a cement hardened matrix. SOLUTION: The fused product of an electric furnace oxidized slag is poured into a drum having blades and rotating at high speed crushed and granulated, and then quenched under cooling a water mist atmosphere to produce the fine aggregates with almost spherical shape having <= about 2.5mm particle size, specific gravity of about 3.5-3.8 and fine ruggedness on the surface or having a hollow structure. Next, a cement slurry is prepared by mixing 100 pts., by wt., cement such as Portland cement, the 300-600 pts. fine aggregates, proper quantity of fine aggregates such as silica sand, silica, a cement hardening control agent, a water reducing agent and about 25-60 pts. water. A wave absorbing block or the underwater block such as fish bank consisting of a concrete molding in which the fine aggregates are dispersed is obtained by a pouring molding method pouring the cement into a flask or an extrusion molding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater block used for a wave-dissipating block or a fish reef, for example.

[0002]

2. Description of the Related Art Conventionally, for example, a concrete molded product in which crushed stone powder, sea sand, river sand, silica sand, etc. are mixed with cement as an aggregate in an underwater block immersed in water of a sea or river such as a wave-dissipating block or fish reef. Is used.

[0003]

The above-mentioned underwater block is required to have high corrosion resistance in order to come into contact with seawater or river water.
In addition, large weight and high strength are required to withstand water flow and buoyancy. However, in the case of the above-mentioned conventional concrete molded product, the corrosion resistance, weight, and strength are insufficient, and there is a possibility that problems such as erosion, shaking, and damage of the underwater block are often caused. In addition, natural resources such as crushed stone powder and river sand as aggregates are currently in short supply and are in a serious condition.

[0004]

Means for Solving the Problems As a means for solving the above problems, the present invention provides a fine aggregate (8) of a substantially spherical electric furnace oxidized slag granule having fine irregularities on the surface in a cement hardened material matrix. The present invention provides an underwater block (11) consisting of a concrete molded material dispersed as Examples of the underwater block include a wave-dissipating block and a fish reef. The present invention will be described in detail below.

[Electric Furnace Oxidation Slag] The electric furnace oxidation slag referred to in the present invention is usually 10 to 26% by weight of CaO and SiO ₂
8 to 22% by weight, MnO 4 to 7% by weight, MgO _{2 to} 8% by weight, Fe O 13 to 32% by weight, Fe ₂ O ₃ 9 to 45% by weight, Al ₂ O ₃ 4 to 16% by weight, Cr ₂ O Includes about _{31 to} 4% by weight and, as a minor component, TiO ₂ 0.25 to 0.7
0 wt%, P ₂ O ₅ 0.15~0.50 wt%, S0.
It contains about 005 to 0.085% by weight and about 20 to 45% by weight of Fe for obtaining a stable mineral composition. It does not contain clay, organic impurities or salt contained in the natural aggregate component at all. Free of stable free lime, free magnesia or minerals.

[Production of Fine Aggregate] In order to produce fine aggregate by granulating the electric furnace oxidation slag, the melt of the electric furnace oxidation slag is poured into a drum with a blade rotating at a high speed, and the melt is obtained. Is crushed and granulated by the bladed drum, and the granulated melt is rapidly cooled in a water mist atmosphere. A plurality of the bladed drums may be arranged to perform crushing and granulation in a plurality of stages. The granulated product of the electric furnace oxidized slag thus obtained is usually classified as a fine aggregate having a particle size of 5 mm or less, and those having a particle size of 2.5 mm or less are substantially spherical and have a specific gravity of 3.3-. It is in the range of 3.8, has no defects such as cracks on the surface, has fine irregularities, and has a hollow structure or includes a hollow structure. The particle size distribution is within the standard range of JIS-A5005 crushed sand for concrete.

[Cement] The cement to which the fine aggregate made of substantially spherical electric furnace oxidized slag granules having fine irregularities on the surface is mixed is, for example, Portland cement.
Alumina cement, fly ash cement, blast furnace slag cement, silica cement and the like.

[Use of Fine Aggregate] The mixing ratio of fine aggregate made of electric furnace oxidized slag granules having fine irregularities on the surface and cement is usually the same as that of conventional natural fine aggregate,
Volume ratio of 300 to 600 for 100 cement
The degree of fine aggregate is mixed. The cement-fine aggregate mixture includes river sand, sea sand, silica sand, crushed stone, crushed sand, pearlite,
Other aggregates such as fly ash and blast furnace slag, a cement hardening regulator, a water reducing agent, and a thickening agent may be added. Water is usually added to the cement-fine aggregate mixture in an amount of 25 to 60 parts by weight based on 100 parts by weight of cement to prepare a cement slurry or a cement kneaded product, which is usually placed in a mold. It becomes a concrete molded product molded into a predetermined shape by cast molding or extrusion molding. Reinforcing bars may be inserted into the concrete molded product for reinforcement, but in this case, cement slurry is poured with the reinforcing bars being inserted in the mold.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[Example 1] (Production of fine aggregate) Fig. 1 shows an apparatus for producing the fine aggregate of the present invention. That is 15
The electric furnace oxidation slag melt (1) at around 00 ° C. is transferred from the ladle (2) to the shooter (3) and poured from the shooter (3) into the high speed rotating bladed drums (4,5). The steelmaking slag melt (1) is crushed by the bladed drums (4,5) to be granulated, and the electric furnace oxidation slag melt is granulated (1A).
Is quenched by the water mist sprayed from the spray device (7) in the quench chamber (6). The fine aggregate (8) thus obtained is stored in the storage container (9). The fine aggregate (8) is substantially spherical, has no defects such as cracks on the surface, has fine irregularities, and has high hardness (Vickers hardness of 755, Mohs hardness of about 6) and wear resistance. Excellent specificity, true specific gravity 3.84, absolute dry specific gravity 3.52,
It has a fire resistance of 1100 ° C. and is excellent in magnetic permeability, conductivity, acid resistance and alkali resistance. The particle size distribution of the fine aggregate (8) is shown in FIG. In FIG. 2, the solid line graph is the aggregate of the present invention.
The particle size distribution and dotted line graph of (8) show the standard range of JIS-A5005 fine aggregate for concrete, and it is recognized that the fine aggregate (8) is within the standard range.

Example 2 A mixture having the following composition was kneaded and prepared using the above fine aggregate. Ordinary Portland cement 540 kg / m ³ Fine aggregate (Example 1 ρ = 3.79) 1213 〃 (320 liters) Coarse aggregate (crushed stone) 916 〃 Silica fume 60 〃 High performance AE water reducing agent 12 〃 Water 135 〃 Above mixture Pour the material into the mold in 30 minutes 20
The slump flow value measured after 2 seconds was 31.5 cm. The above composition is poured into a mold to mold a block of φ10 cm × 20 cm, and the compression strength of the block after molding is measured daily. The results are shown in Table 1.

[Table 1]

[Comparative Example 1] A mixture having the following composition was kneaded and prepared using river sand as fine aggregate. Normal Portland cement 540 kg / m ³ Fine aggregate (Kawasuna ρ = 2.56) 819 〃 (320 liters) Coarse aggregate (crushed stone) 916 〃 Silica fume 60 〃 High performance AE water reducing agent 12 〃 Water 135 〃 Pour into formwork with kneading time of 30 minutes 20
The slump flow value measured after 2 seconds was 24.0 cm. The above-mentioned composition was poured into a mold to form a block similar to that in Example 2, and the compression strength of the block was similarly measured daily. The results are shown in Table 2.

[Table 2]

Comparing Table 1 of Example 2 with Table 2 of Comparative Example 1, the block made of the compound of Example 2 is superior to the compound of Comparative Example 1 (conventional example) in strength, particularly in initial strength. It was recognized that From the slump flow value, it was confirmed that the compound of Example 2 was superior in moldability to the compound of Comparative Example 1 (conventional example).

[Corrosion Resistance Test] The compositions of Example 2 and Comparative Example 1 were cast into molds to form blocks of φ10 cm × 20 cm, and each block was allowed to stand for 28 days and then immersed in seawater for a period of time. The compressive strength (N / mm ² ) was measured. Table 3 shows the results.

[Table 3] As seen from Table 3, the block of the compound of Example 2 shows excellent corrosion resistance with little decrease in compressive strength over time even when immersed in seawater, while the block of the compound of Comparative Example 1 has an excellent corrosion resistance. It was found that the compressive strength of the block was lower than that of the block of No. 1 and that the strength was significantly decreased with time when immersed in seawater.

[Application Example] Using the composition of Example 2, various molded products were molded by cast molding. Fig. 3 shows a so-called tetrapod wave-dissipating block (11),
A fish reef (21) is shown in FIG. 4, and the fish reef (21) is composed of a stack of a plurality of cylindrical blocks (22).

[0015]

EFFECTS OF THE INVENTION The fine aggregate used in the present invention has a substantially spherical shape and has fine irregularities on the surface, and the concrete has an extremely good adhesion to the concrete due to the anchoring effect that bites into the irregularities, so that it has excellent corrosion resistance. A strong underwater block can be obtained. Further, since the fine aggregate has a substantially spherical shape, the slurry has good fluidity, excellent filling properties when poured into a mold, an underwater block having a predetermined shape can be accurately obtained, and defects such as burrows do not occur. . Since the underwater block using the fine aggregate has a large weight, it can withstand buoyancy even when immersed in seawater or river water. Since the fine aggregate of the present invention is obtained from the electric furnace oxidizing slag which is an industrial waste generated in the steelmaking process, there is no resource problem and the electric furnace oxidizing slag can be effectively used.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an aggregate manufacturing apparatus.

FIG. 2 is a graph showing a particle size distribution of an aggregate. FIGS. 3 and 4 show application examples of the present invention.

FIG. 3 is a perspective view of a wave breaking block.

[Figure 4] Perspective view of fish reef

[Explanation of symbols]

 8 Fine aggregate 11 Wave-dissipating block (underwater block) 21 Fish reef (underwater block)

Claims (3)

[Claims] 1. An underwater block characterized by comprising a concrete molded product in which a substantially spherical electric furnace oxidized slag granule having fine irregularities on the surface is dispersed as a fine aggregate in a cement hardened product matrix. 2. The underwater block according to claim 1, wherein the underwater block is a wave-dissipating block. 3. The underwater block according to claim 1, wherein the underwater block is a fish reef.