JPH08157246A - Ceramic fine aggregate for concrete - Google Patents

Abstract

PURPOSE: To cope with the shortage of a high quality fine aggregate in future, when the development and security of natural sources as the fine aggregate will become difficult, by forming a spherical electric furnace oxidizing slag granulated body, having fine ruggedness on the surface. CONSTITUTION: An electric furnace oxidizing slag fused material containing 10-26wt.% CaO (hereafter in wt.%), 8-22% SiO2 , 4-7% MnO, 2-8% MgO, 13-32% FeO, 9-45% Fe2 O3 , 4-16% Al2 O3 , 1-4% Cr2 O3 , 0.25-0.70% TiO2 , 0.15-0.50% P2 O5 , 0.005-0.08% P and 20-46% Fe, containing completely no clay, no organic impurities and no salt matter and hardly containing free lime, free magnesia and minerals is injected into a drum with propeller, crushed, granulated and quenched in a water mist atmosphere to make a fine aggregate having <=0.5mm particle diameter and the resulting spherical fine aggregate having <=2.5mm particle diameter, 3.3-3.8 specific gravity, free from crack, having fine ruggedness on the surface and composed of a hollow structure is made into slurry by adding cement, water and if necessary, an admixture and the slurry is fed to a molding flask to obtain a concrete product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic fine aggregate for concrete used in concrete buildings, concrete structures, concrete moldings and the like.

[0002]

2. Description of the Related Art As a conventional fine aggregate for concrete,
Natural resources such as river sand, silica sand, and crushed sand are mainly used.

[0003]

However, it is said that it will be inevitable that the development and securing of natural resources as the above-mentioned fine aggregate will gradually become difficult, and that there will be a shortage of high-quality fine aggregate for concrete in the future.

[0004]

Means for Solving the Problems As a means for solving the above problems, the present invention provides a ceramic-based fine aggregate for concrete, which is made of substantially spherical electric furnace oxidized slag granules having fine irregularities on the surface. It is desirable that the electric furnace oxidation slag granules have a hollow structure, or a ceramic fine aggregate for concrete containing a hollow structure. The present invention is 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 bladed drums may be arranged to carry out crushing 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 above cement-fine aggregate mixture may be added with other aggregates such as river sand, silica sand, crushed stone, crushed sand, perlite, fly ash, blast furnace slag, cement hardening regulator, water reducing agent, thickener and the like. . Water is usually added to the cement-fine aggregate mixture in an amount of 25 to 60 parts by weight per 100 parts by weight of cement to form a slurry, and the slurry of the cement-fine aggregate mixture is usually poured into a mold. Then, it becomes a concrete product such as a building or a building frame, or a concrete molded product such as a tetrapot. In the case of the skeleton of a building or structure, reinforcing bars are inserted in the formwork.

[0009]

The fine aggregate of 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. Further, since the fine aggregate of the present invention has a high specific gravity and has a hollow structure or includes a hollow structure, the heat insulating property and sound insulating property of the concrete product are improved. Further, since the fine aggregate of the present invention has a substantially spherical shape, it has a good fluidity of the slurry, an excellent filling property when poured into a mold, a predetermined shape can be accurately obtained, and defects such as burrows do not occur. 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.

[0010]

【Example】

[Production of Fine Aggregate] FIG. 1 shows an apparatus for producing the fine aggregate of the present invention. That is, electric furnace oxidation slag melt at around 1500 ° C
(1) Transfer the ladle (2) to the shooter (3) and inject it from the shooter (3) into the high speed rotating bladed drums (4,5). The steelmaking slag melt (1) is the vaned drum (4,5)
The granulated product (1A) of the electric furnace oxidation slag melt is crushed into particles by means of water mist sprayed from the spray device (7) into 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 (755 Vickers hardness, about 6 Mohs hardness). It also has excellent abrasion resistance, a true specific gravity of 3.84, an absolute dry specific gravity of 3.52, and a fire resistance of 1100 ° C, and is excellent in magnetic permeability, conductivity, acid resistance, alkali resistance and the like. The particle size distribution of the fine aggregate (8) is shown in FIG. In FIG. 2, the solid line graph is the particle size distribution of the aggregate (8) of the present invention, and the dotted line graph is JIS-A50.
05 Indicates the standard range of fine aggregate for concrete,
It is recognized that (8) is within the standard range.

[Example 1] Using the above fine aggregate and natural silica sand as a comparison, the fine aggregate and cement were mixed at a volume ratio of 4.0, and water was added to each mixture to form a mortar. It was prepared and adjusted so that the flow value of the mortar was 180 mm. Table 1 shows the water-cement ratio (weight ratio) in this case.
Shown in The fine aggregate of the present invention and the particle size of natural silica sand are JIS
-A5005 The same particle size was used after sieving so as to have a particle size in the center of the crushed concrete standard.

[Table 1] As shown in Table 1, when the fine aggregate of the present invention is used, it is recognized that the water-cement ratio for achieving the same flow value is much lower than that when natural silica sand is used. .

After molding each of the above mortars into a block material of 4 cm × 4 cm × 16 cm and curing in a constant temperature water bath at 20 ° C.,
The bending strength and the compressive strength of each block material were measured on the 1st, 3rd, 7th and 28th days of the material age. The results are shown in Table 2.

[Table 2] Block material A: Use fine aggregate of the present invention Block material B: Use natural silica sand According to Table 2, the block material A using the fine aggregate of the present invention is a block material using natural silica sand as fine aggregate. It is recognized that both flexural strength and compressive strength are much higher than those of B. These results indicate that the fine aggregate of the present invention has a substantially spherical shape, so that the amount of water required to prepare a mortar exhibiting the same flow value as compared with natural silica sand is significantly small, and Since the fine aggregate of the present invention has fine irregularities on the surface, this is due to the anchoring effect that cement bites into the irregularities.

[Embodiment 2] The fine aggregate of the present invention has a particle size of 5
The kneaded material shown in Table 3 was prepared by using the material sieved to a size of less than mm.

[Table 3] Fill the mold with the above kneaded product and have a thickness of 100 mm and a height of 190.
A hollow concrete block (weight block) having a length of 390 mm and a length of 390 mm was molded. Regarding the weight block, JIS
Table 4 shows the results of measuring the sound transmission loss in the laboratory by the sound transmission loss measurement method of A1416.

[Table 4] As shown in Table 4, the weight block using the fine aggregate of the present invention exhibits much higher sound transmission loss from the low frequency band to the high frequency band as compared with the commercially available weight block. It is considered that this is because the fine aggregate of the present invention has a hollow structure and thus has a large sound absorbing effect in addition to the mass effect.

Example 3 The above fine aggregate was sieved to a particle size of 1.2 mm or less, and then a mixture having a formulation shown in Table 5 below was prepared.

[Table 5] Composition B is a comparative composition in which the fine aggregate of the present invention is not added.

Table 6 shows the results of the slump flow test and the filling test 20 seconds after the mixture of the compositions A and B was kneaded and placed in the mold for 30 minutes.

[Table 6] According to Table 6, the mixture of composition A using the fine aggregate of the present invention exhibits much higher slump flow and filling value than the mixture of composition B not using the fine aggregate of the present invention.

[0017]

EFFECTS OF THE INVENTION The ceramic fine aggregate for concrete of the present invention does not consume natural resources and uses electric furnace oxidation slag, which is generated in a large amount in the electric furnace steelmaking process, as a raw material, so that there is no resource problem. The electric furnace oxidation slag can be effectively used. Since the ceramic fine aggregate for concrete of the present invention has a substantially spherical shape and has fine irregularities on the surface and has a large specific gravity, it is made of a hollow structure or includes a hollow structure, Useful as a material,
In addition, it has good adhesion to concrete, has excellent mechanical strength, heat insulation, and sound insulation, and is a sound block for heavy blocks, highway sound insulation walls, etc., building structure walls, tetrapots, fish reefs, and fumes. It exhibits excellent performance when used in concrete products such as pipes, underdrain blocks, concrete blocks, L-shaped retaining walls, sheet piles, piles, sewer manhole covers, surface plates, stair blocks, and paving stones.

[Brief description of drawings]

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

FIG. 2 is a graph showing the particle size distribution of aggregate.

[Explanation of symbols]

 1 Electric furnace Oxidized slag melt 4,5 Drum with blade 6 Cooling chamber 7 Water mist spray device 8 Fine aggregate

Claims (2)

[Claims] 1. A fine ceramic aggregate for concrete, comprising a substantially spherical electric furnace oxidized slag granule having fine irregularities on the surface. 2. The fine ceramic aggregate for concrete according to claim 1, wherein the granulated product of the electric furnace oxidized slag has a hollow structure or includes a hollow structure.