JP2022146316A - Coarse aggregate for concrete - Google Patents

Abstract

To provide a coarse aggregate capable of greatly increasing a tensile strength of concrete.SOLUTION: The present invention relates to a coarse aggregate 1A for concrete having a coarse aggregate main body 2 formed from a concrete material and a high strength steel material 10 embedded in the coarse aggregate main body 2. A compression stress is applied to the coarse aggregate main body 2 by the high strength steel material 10. As the high strength steel material 10, a high strength steel wire 11 such as a PC steel wire, a PC steel stranded wire, and a piano wire, or a high strength steel mesh 12 formed from a high strength steel wire can be used. This coarse aggregate can be formed into an aggregate 1X of a coarse aggregate with a plurality of coarse aggregate main bodies 2 being embedded in one piece of the high strength steel mesh 12.SELECTED DRAWING: Figure 1A

Description

The present invention relates to coarse aggregate for concrete.

Concrete is usually made by mixing cement, water, coarse aggregate (crushed stone and gravel) and fine aggregate (sand), so-called ready-mixed concrete, and solidifying it based on the hydration reaction between water and cement. It is widely used as a building material.

Concrete has the disadvantage that its tensile strength is very low compared to its compressive strength. In order to make up for this shortcoming, it is common to arrange reinforcing bars in a matrix in the concrete, but in order to improve not only the compressive strength but also the tensile strength, it is necessary to use a specific coarse aggregate. is proposed.

For example, coarse aggregate is formed of concrete material such as cement and sand, and iron pieces or the like are mixed as a reinforcing material inside (Patent Document 1), and a coarse aggregate body is formed of metal material such as pipe, There are those in which a wire protrudes from there (Patent Document 2), and those in which a metallic mesh material is formed into a spherical shape with a flange (Patent Document 3).

JP-A-63-206337 Japanese Patent No. 6532073 Japanese Patent No. 6667886

However, as described in Patent Document 1, even if iron pieces or the like are simply mixed into the interior of a coarse aggregate body formed of a concrete material such as cement or sand, the tensile strength of concrete using it is greatly improved. It is not possible.

On the other hand, if the coarse aggregate is made of a metal material as described in Patent Document 2, the tensile strength of the coarse aggregate itself is too strong compared to the mortar portion of concrete, so the interface between the coarse aggregate and mortar separates. As a result, the mortar part may break, and the coarse aggregate may not contribute to improving the tensile strength of the concrete.

As described in Patent Document 3, the coarse aggregate obtained by forming the metal mesh material into the hollow is integrated with the metal mesh material and the mortar. can be prevented. Therefore, this coarse aggregate can improve the compressive strength and tensile strength of concrete more than the conventional coarse aggregate. However, there is a demand for the development of coarse aggregate that can further increase the tensile strength of concrete.

In contrast to such prior art, an object of the present invention is to provide a coarse aggregate that can greatly improve the tensile strength of concrete.

When the coarse aggregate is formed from a concrete material, the tensile strength of the coarse aggregate is increased by applying a compressive stress to the coarse aggregate by a high-strength steel material on the same principle as PC concrete. The present invention was completed based on the idea that the tensile strength of concrete using this coarse aggregate would be improved.

That is, the present invention provides a coarse aggregate for concrete having a coarse aggregate main body made of a concrete material and a high-strength steel material embedded in the coarse aggregate main body, wherein the high-strength steel material is attached to the coarse aggregate main body. To provide a coarse aggregate for concrete to which compressive stress is applied.

The present invention also provides a method for producing coarse aggregate for concrete having a coarse aggregate body made of a concrete material and a high-strength steel material embedded in the coarse aggregate body, wherein a tensile force is applied to the high-strength steel material. Provided is a method for producing coarse aggregate for concrete, in which a concrete material is pressure-molded so that the high-strength steel material is embedded while being applied.

According to the coarse aggregate for concrete of the present invention, compressive stress is applied to the coarse aggregate body formed of concrete material by the high-strength steel material, so the coarse aggregate body is compressed on the same principle as PC concrete. Improves strength.
Therefore, concrete using this coarse aggregate for concrete has improved compressive strength.

FIG. 1A is a perspective view of a coarse aggregate for concrete 1A of an example. FIG. 1B is a cross-sectional view of the coarse aggregate for concrete 1A of the example. FIG. 2 is an explanatory view of the method of manufacturing the coarse aggregate for concrete 1A of the embodiment, and is a plan view of a state in which a tensile force is applied to the PC steel wire. FIG. 3A is an explanatory diagram of the method for manufacturing the coarse aggregate for concrete 1A of the embodiment, and is a plan view showing a state in which the main body of the coarse aggregate is pressure-molded while applying a tensile force to the PC steel wire. FIG. 3B is an explanatory view of the method for producing the coarse aggregate for concrete 1A of the example, and is a cross-sectional view showing a state in which the main body of the coarse aggregate is pressure-molded while applying a tensile force to the PC steel wire. FIG. 4 is an explanatory view of the method of manufacturing the coarse aggregate for concrete 1A of the embodiment, and is a cross-sectional view of a state in which the main body of the coarse aggregate is pressure-formed by a hydraulic jack while applying a tensile force to the PC steel wire. is. FIG. 5A is a perspective view of the coarse aggregate for concrete 1B of the example. FIG. 5B is a cross-sectional view of the coarse aggregate for concrete 1B of the example. FIG. 6 is an explanatory view of the method of manufacturing the coarse concrete aggregate 1B of the embodiment, and is a plan view of a state in which a tensile force is applied to the PC steel wire. FIG. 7 is an explanatory view of the method of manufacturing the coarse aggregate for concrete 1B of the embodiment, and is a plan view showing a state in which the main body of the coarse aggregate is pressure-formed while applying a tensile force to the PC steel wire. FIG. 8A is a perspective view of an aggregate of coarse concrete aggregate 1B of the example. FIG. 8B is a cross-sectional view of an aggregate of coarse concrete aggregate 1B of the example. FIG. 9 is a cross-sectional view of a state in which an aggregate of coarse aggregates 1B for concrete of Examples is separated into individual coarse aggregates 1B for concrete of Examples.

Hereinafter, the coarse aggregate for concrete of the present invention will be described in detail with reference to examples. In each figure, the same reference numerals denote the same or equivalent components.

(Overall composition of coarse aggregate for concrete)
FIG. 1A is a perspective view of a coarse aggregate for concrete 1A according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view thereof taken along the line xx. This coarse aggregate for concrete 1A has a coarse aggregate body 2 made of a concrete material and a plurality of high-strength steel wires 11 as high-strength steel materials 10 . Each high-strength steel wire 11 has its central portion embedded in the coarse aggregate body 2 and both ends protruding from the coarse aggregate body 2 .

Compressive stress is applied to the coarse aggregate body 2 by high-strength steel wires 11, as indicated by arrows in FIG. 1B. This compressive stress is applied to the coarse aggregate body 2 based on the same principle as the pretension method for PC concrete. The coarse aggregate body 2 is press-molded with the be under compressive stress. Therefore, this coarse aggregate for concrete 1A has improved tensile strength compared to coarse aggregate in which reinforcing metal is simply mixed, and the tensile strength of concrete obtained by mixing this coarse aggregate for concrete is Strength can be improved.

When the coarse aggregate 1A for concrete is mixed with fresh concrete and the ready-mixed concrete is hardened, the projecting portion of the high-strength steel wire 11 from the coarse aggregate body 2 connects the coarse aggregate 1A for concrete and the concrete. Acts as an anchor. Furthermore, since the coarse aggregate body 2 of the coarse aggregate for concrete 1A is made of a concrete material, it has a good affinity with the concrete mixed with the coarse aggregate for concrete 1A. Therefore, from these points as well, the adhesion between the coarse aggregate for concrete 1A and concrete is improved, and the tensile strength of concrete can be improved.

(Coarse aggregate body)
The coarse aggregate body 2 is made of a concrete material obtained by mixing cement and sand or further fine aggregate such as gravel. The concrete material itself is not particularly limited, and various known concrete materials can be used.

In the present invention, the shape of the coarse aggregate body 2 is not particularly limited, and in this embodiment, it is substantially spherical. The size of the coarse aggregate body 2 can be approximately the same as that of the conventional coarse aggregate. More specifically, it is preferable to set the particle size and particle size within the range specified in JIS A 5308, and it is preferable to set the particle size L1 to 5 to 25 mm.

(high-strength steel)
In the present invention, as the high-strength steel material, a steel material having a tensile strength of 690 N/mm ² or more can be used from the viewpoint of imparting high compressive stress to the coarse aggregate body. Examples of high-strength steel materials include PC (Prestressed Concrete) steel wires, tendons for PC such as PC steel stranded wires, and high-strength steel wires selected from piano wires and the like. As the high-strength steel material, a high-strength steel mesh made by woven high-strength steel wire may be used.

The wire diameter of the high-strength steel material 10 can be appropriately selected according to the number of high-strength steel wires 11 used as the high-strength steel material. In addition, the size of the entire coarse aggregate 1A including the high-strength steel wire 11 is set to be about the same as that of the conventional coarse aggregate, and the high-strength steel wire 11 is used in order not to interfere with the pumping of ready-mixed concrete. is preferably 5 cm or less.

(Production method)
1 A of coarse aggregates for concrete shown in FIG. 1A can be manufactured as follows.
First, a tensile force is applied to the high-strength steel wire 11 as shown in FIG. The strength of the tensile force shall be within the elastic limit of the high-strength steel wire 11 .

Next, as shown in FIG. 3A and FIG. 3B , the central portion of the high-strength steel wire 11 is embedded in the coarse aggregate body 2 while a tensile force is applied to both ends of the high-strength steel wire 11 . A molding die 3 is used to pressure-mold the coarse aggregate body 2 . As a result, the coarse aggregate main body 2 fixes the state in which the high-strength steel wire 11 is pulled, that is, the state in which the high-strength steel wire 11 has a compressive force against the tensile force. As a method for pressure molding the coarse aggregate body 2, as shown in FIG. 4, pressure compaction can be mentioned, in which a molding die 3 for the coarse aggregate body is pressurized by a hydraulic jack or the like. The pressurization conditions in this case can be appropriately determined according to the composition of the concrete material.

(Modification mode)
The coarse aggregate for concrete of the present invention can take various modifications.
The coarse aggregate 1B for concrete shown in FIGS. 5A and 5B is a high-strength steel material 10 in which high-strength steel wires having a finer diameter are used as a plain-woven mesh instead of the high-strength steel wires 11 described above. The mesh 12 is used. Note that the type of mesh is not limited to plain weave.

At the time of manufacturing the coarse concrete aggregate 1B, first, a tensile force is applied to the high-strength steel wires forming the high-strength steel mesh 12 . In this case, as shown in FIG. 6, it is preferable to apply a tensile force to each of the high-strength steel wires in two orthogonal directions forming the high-strength steel mesh 12 . Moreover, when the tensile force is applied in two directions, the tensile force in the two directions may be applied at the same time, or the tensile force in one direction may be applied and then the tensile force in the other direction may be applied.

After applying tensile force to the high-strength steel mesh 12, as shown in FIG. Coarse aggregate for concrete 1B is obtained from which the high-strength steel mesh 12 protrudes like a flange.

According to this coarse aggregate for concrete 1B, since the high-strength steel mesh 12 protrudes in a flange shape from the coarse aggregate body 2, the coarse aggregate for concrete 1B and the concrete are stronger than the coarse aggregate for concrete 1A described above. improves adhesion.

FIG. 8A is a perspective view of aggregate 1X of coarse aggregate 1B for concrete obtained by forming a plurality of coarse aggregate bodies of coarse aggregate 1B for concrete on one sheet of high-strength steel mesh 12. FIG. and FIG. 8B is its xx sectional view. In this aggregate 1X, the high-strength steel meshes 12 between the coarse aggregate bodies 2 are formed with halving lines 13 separating the individual coarse aggregates 1B for concrete. Therefore, as shown in FIG. 9, the aggregate of coarse aggregates 1B for concrete can be easily separated into individual coarse aggregates 1B for concrete.

If the aggregates for concrete are easily separable in this way, the aggregates can be stored and transported in a stacked state. Since the coarse aggregate can be used after being separated from the aggregate, the handling of the coarse aggregate during storage and transportation is improved.

(Application example of coarse aggregate)
The coarse aggregate for concrete of the present invention can replace part or all of the coarse aggregate in the conventional concrete composition. As a preferred application example of the coarse aggregate for concrete of the present invention, for example, in concrete precast products, the coarse aggregate of the present invention can be used to manufacture reinforced concrete plates that are stronger than before against tension and bending. . It is also preferably applicable to concrete structures that do not use reinforcing bars (eg, dam walls, roads laid directly on the ground, mat foundations of buildings, paved open spaces, etc.). As a special application example, it can be preferably applied to a reinforced concrete floor slab of a highway, which is installed at a position away from the ground.
In these applications, the coarse aggregate for concrete of the present invention may be used in the form of aggregates as described above, if desired. This aggregate can be widely used as a civil engineering and building material.

In addition, when magnetic steel such as PC steel is used as the high-strength steel, the concrete panel using the coarse aggregate for concrete of the invention can be attracted to an electromagnet to be transported, installed, and removed, resulting in workability. improves.

1A, 1B Coarse aggregate 1X Aggregate 2 Coarse aggregate body 3 Mold 10 High-strength steel material 11 High-strength steel wire 12 High-strength steel mesh 13 Half cutting line

Claims (6)

A coarse aggregate for concrete comprising a coarse aggregate body made of a concrete material and a high-strength steel material embedded in the coarse aggregate body, wherein the high-strength steel material imparts a compressive stress to the coarse aggregate body. Coarse aggregate for concrete. 2. The coarse aggregate for concrete according to claim 1, wherein the high-strength steel material includes high-strength steel wires, and both ends of the high-strength steel wires protrude from the coarse aggregate body. 2. The coarse aggregate for concrete according to claim 1, wherein the high-strength steel material comprises a high-strength steel mesh made of high-strength steel wire, and the high-strength steel mesh protrudes like a flange from the coarse aggregate body. 4. The coarse aggregate for concrete according to claim 3, wherein one high-strength steel mesh is embedded in a plurality of coarse aggregate bodies, and the high-strength steel mesh between the coarse aggregate bodies is formed with a half cutting line. material. The coarse aggregate for concrete according to any one of claims 1 to 4, wherein the high-strength steel wire is selected from PC steel wire, PC steel stranded wire and piano wire. A method for producing a coarse aggregate for concrete having a coarse aggregate body made of a concrete material and a high-strength steel material embedded in the coarse aggregate body, wherein the high-strength steel material is applied with a tensile force. A method for producing coarse aggregate for concrete, in which a concrete material is pressure-molded so that steel material is embedded.

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