Patent Application
20200354273
The present invention relates to a coarse aggregate for concrete.
Concrete is a substance normally obtained by solidifying so-called fresh concrete, which is obtained by mixing water, a coarse aggregate (crushed stone or gravel), and a fine aggregate (sand) in cement, on the basis of a hydration reaction of the water and the cement. Such concrete is widely used as a constructional material.
Concrete has a disadvantage of exhibiting very low tensile strength and bending strength compared to compressive strength. In order to compensate the concrete for such a disadvantage, it is generally performed that reinforcing bars assembled in a matrix (or lengthwise and breadthwise) form are disposed in concrete. There have been known a technique in which propylene fibers are contained as a reinforcing fiber in fresh concrete (Patent Literature 1), a technique in which organic fibers, amorphous steel fibers, or the like are contained in fresh concrete (Patent Literature 2), and a technique in which a reinforcing material such as an iron piece, a steel piece, high tensile strength carbon fibers, or glass fibers are protruded from an artificial aggregate forming material formed from expanded shale or the like (Patent Literature 3). Further, for the purpose of improving compressive strength and tensile strength by the shape of a coarse aggregate itself, there have been proposed, for example, a coarse aggregate in which spheres with a flange, each obtained by disposing two hemispherical molding products formed by pressing out a metal plate so as to face each other and bonding them to each other, are connected to each other by a connection portion having a narrow width (Patent Literatures 4 and 5) and a coarse aggregate having a shape in which both ends of a metal pipe are closed in a mutually different direction (Patent Literature 6). Further, for the purpose of improving adhesion between a metallic coarse aggregate and mortar, there have been proposed a coarse aggregate in which a thin wire of gauge No. 20 or more penetrates a metallic coarse aggregate body such that the wire is easily wound around the coarse aggregate body (Patent Literature 7). According to this coarse aggregate, the wire is wound around the coarse aggregate body during stirring of the fresh concrete, and the mortar is further captured by the wound wire, causing the coarse aggregate and the mortar to move integrally. This can provide an advantage in that the coarse aggregate is less likely to be sedimented in the fresh concrete, leading to excellent dispersibility of the coarse aggregate.
Patent Literature 1: Japanese Patent Application Laid-Open No. 2017-178755
Patent Literature 2: Japanese Patent Application Laid-Open No. 2001-220201
Patent Literature 3: Japanese Patent Application Laid-Open No. Sho. 63-206337
Patent Literature 4: Japanese Utility Model Registration Publication No. Sho. 45-7674
Patent Literature 5: Japanese Utility Model Registration Publication No. Sho. 45-7675
Patent Literature 6: Japanese Patent No. 6485932
Patent Literature 7: Japanese Patent No. 6532073
In a case where the reinforcing fiber is mixed in the fresh concrete as described in Patent Literatures 1 and 2, the reinforcing fiber is sometimes aggregated instead of being uniformly dispersed in the whole fresh concrete. In such a case, various strengths may vary from place to place in a concrete construction, causing a problem in which stress is concentrated on a location where the strength is relatively low, likely resulting in the occurrence of cracking in the concrete. Further, the reinforcing fiber is not an essential constituent component of the concrete conventionally used. Thus, there is a concern that using the reinforcing fiber makes it difficult to perform blending and adjustment of the constituent component of the concrete for obtaining predetermined concrete properties.
On the other hand, according to the coarse aggregates described in Patent Literatures 3 to 6, they can be used instead of the conventional coarse aggregate formed from crushed stones or gravel, and thus, the blending of the constituent component of the concrete can be easily adjusted. Further, the metallic coarse aggregates described in Patent Literatures 4 to 6 make it possible to increase tensile strength as compared with the conventional coarse aggregate. However, the coarse aggregates described in Patent Literatures 4 to 6 are easily sedimented in the fresh concrete, causing a problem of making it difficult to obtain the concrete in which the coarse aggregates are uniformly dispersed. In addition, it is also desired to further improve compressive strength and tensile strength.
Further, as described in Patent Literature 7, winding the wire around the metallic coarse aggregate body can improve the adhesion between the coarse aggregate and the mortar. However, inconsistency of the winding of the wire around the coarse aggregate body may cause variation in the tensile strength.
In order to cope with these problems of the conventional techniques of Patent Literatures 1 to 6, it is an object of the present invention to provide a novel material, which can be used as a coarse aggregate serving as an essential constituent component of concrete, which can further improve compressive strength and tensile strength of concrete, which is less likely to be sedimented in fresh concrete, and which can be obtained with high productivity and at a low cost. Further, besides the aforementioned problems, in order to cope with the problem of the conventional technique of Patent Literature 7, it is another object of the present invention to significantly improve tensile strength of concrete by more reliably improving adhesion between mortar and a coarse aggregate and thereby preventing breakage of a mortar part.
The present inventor has found that a coarse aggregate body having a shape of sphere or a shape similar to sphere (hereinafter, sometimes referred to as a spherical shape) has high strength to compression and tension in any direction due to its shape, and thus concrete prepared by using this coarse aggregate body can improve compressive strength and tensile strength, and that the coarse aggregate body having a shape of sphere or a shape similar to sphere can be easily produced by bonding two spherical cap portions, or the like.
Further, the present inventor has found that, in the production of the spherical coarse aggregate, an annular portion is protruded so as to surround the outer periphery of the spherical shape, the annular portion is rectangularly shaped, and, further, corners of the annular portion are bent, so that the spherical shape having the rectangular annular portion, not only exhibits the aforementioned advantageous effect, but also can be extremely easily produced by press processing using a metal plate or a metal pipe without generating punched debris.
Further, the present inventor has found that, when the coarse aggregate includes a plurality of the spherical portions having a shape of sphere or a shape similar to sphere, and the coarse aggregate has a sufficient width equal to or greater than the minimum diameter of the spherical portions in a connection portion where the plurality of spherical portions are directly connected to each other, the coarse aggregate has high strength to compression and tension in any direction due to its shape and thus exhibits the above advantageous effect. Furthermore, the present inventor has found that the shape of the coarse aggregate in which the connection portion of the spherical portions has the width equal to or greater than the minimum diameter of the spherical portions makes it possible to omit a punching step for forming the connection portion, which can increase productivity of the coarse aggregate, that the annular portion protruded from the surface of the spherical portions so as to surround the outer periphery of the plurality of spherical portions improves adhesion between the coarse aggregate and mortar, which can also improve strength of the concrete as well as dispersibility in the fresh concrete, and that the annular portion reduces the tendency of rolling of the coarse aggregate, which can improve handleability of the coarse aggregate.
Furthermore, the present inventor has found that, when the coarse aggregate body having a shape of sphere or a shape similar to sphere is made hollow, a plurality of flexible wires penetrates the hollow coarse aggregate body, and, for example, the plurality of wires protrudes from the coarse aggregate body or an outer fitting portion in which the wires are bent into an annular shape is externally fitted to the hollow coarse aggregate body, the coarse aggregate is less likely to be sedimented in the fresh concrete, which can improve dispersibility in the concrete. The present inventor has found that, in particular, when a plurality of the wires which have small diameters and are easily bent are used and the protrusion lengths of the wires have a sufficient length for the coarse aggregate body to be wound and entangled with the wires, the coarse aggregate body is wound and entangled with the wires by stirring of the fresh concrete or the like, thereby being covered with the wires, and the mortar is then captured by the wires, causing the actual specific gravity of the coarse aggregate to approach that of the mortar, and as a result, the coarse aggregate is further less likely to be sedimented in the fresh concrete and dispersibility in the concrete is improved. The present inventor has also found that, although, according to the descriptions in Patent Literatures 4 and 5, the punching step is required for the forming process of the shape in which the metal plate is molded into a spherical shape and then the spherical coarse aggregates are connected to each other by the connection portion having a narrow width, such a punching step is not required for the coarse aggregate including the coarse aggregate body and the wires, making it possible to reduce a production cost of the coarse aggregate accordingly.
Further, the present inventor has found that, when a specific metallic mesh material molded so as to be hollow is used as a coarse aggregate for concrete, the mortar intrudes inside the coarse aggregate through a hole of the metallic mesh material forming the outer surface of the coarse aggregate, and the metallic mesh material and the mortar are strongly integrated with each other after hardening of the fresh concrete, resulting in significant improvements in compressive strength, shearing strength, and bending strength of the hardened concrete.
The present inventor has made the following first to fourth modes of the present invention on the basis of the aforementioned findings.
That is, a first mode of the present invention provides a metallic coarse aggregate for concrete including a coarse aggregate body including a spherical cap portion bonded body having two hollow spherical cap portions and an annular portion protruding from a surface of the spherical cap portion bonded body so as to surround an outer periphery of the spherical cap portion bonded body, the annular portion having a shape in which a corner of a rectangular shape is bent upward or downward.
Further, the first mode of the present invention provides, as a method for producing the above-described coarse aggregate for concrete, a method for producing a coarse aggregate for concrete including: performing press processing using a rectangular metal plate to form a spherical cap portion with flange having a rectangular flange at a bottom portion thereof; disposing the bottom portions of two spherical cap portions with flange so as to face each other; and pressure-bonding the flanges of the two spherical cap portions with flange to each other by press processing and bending a corner of a rectangular annular portion upward or downward.
According to the first mode of the present invention, the coarse aggregate body of the coarse aggregate for concrete, in which the spherical cap portion bonded body has a shape of sphere or a shape similar to sphere, exhibits high strength to compression and tension in any direction. Further, since the annular portion protrudes from the surface of the spherical cap portion bonded body so as to surround the outer periphery of the spherical cap portion bonded body, adhesive force between the coarse aggregate body and a mortar portion of concrete is improved. Further, since this annular portion is formed in a shape in which the corner of the rectangle is bent, the coarse aggregate is formed by press molding from a metal plate or a metal pipe without generating debris, and a die is also easily created. As a result, the coarse aggregate body can be produced with high productivity and at a low cost, therefore being useful as a building material that is consumed in large quantities.
A second mode of the present invention provides a metallic coarse aggregate for concrete including a plurality of spherical portions, and an annular portion protruding from the surface of the spherical portions so as to surround the outer periphery of the plurality of spherical portions. In such a coarse aggregate for concrete, the plurality of spherical portions are directly connected to each other, and the width of the coarse aggregate in a connection portion of the spherical portions on a surface formed by the outer edge of the annular portion is equal to or greater than the minimum diameter among the diameters of the plurality of spherical portions. In particular, the second mode of the present invention provides an aspect in which a flexible wire penetrates the spherical portion and protrudes from the annular portion or the spherical portion.
Further, the second mode of the present invention provides, as a method for producing the aforementioned metallic coarse aggregate for concrete, a method for producing a coarse aggregate for concrete including: performing press processing using a metal plate to form the spherical cap portions with flange in which bottom portions of the spherical cap portions are continued by the flange; and welding the flanges of two spherical cap portions with flange to each other. Further, the second mode of the present invention provides the method for producing a coarse aggregate for concrete in which the spherical portion and the annular portion are molded by press processing using a metal bar or a metal pipe.
Further, the second mode of the present invention provides, as a method for producing the aforementioned metallic coarse aggregate for concrete in the aspect in which the flexible wire penetrates the spherical portion and protrudes from the annular portion or the spherical portion, a method for producing a coarse aggregate for concrete including performing press processing using a metal plate to form the spherical cap portions with flange in which the bottom portions of the spherical cap portions are continued by the flange, disposing the bottom portions of two spherical cap portions with flange so as to face each other via the flexible wire, and welding the opposing flanges to each other; a method for producing a coarse aggregate for concrete including passing the flexible wire through inside a metal pipe, and performing press processing using the metal pipe through which the wire is passed to form the spherical portion and the annular portion such that the wire protrudes from the annular portion; and a method for producing a coarse aggregate for concrete including performing press processing using a metal bar or a metal pipe to form the spherical portion and the annular portion, making a through-hole in the spherical portion, and passing the flexible wire through the through-hole.
According to the second mode of the present invention, the coarse aggregate for concrete includes the plurality of spherical portions having a shape of sphere or a shape similar to sphere, the plurality of spherical portions are directly connected to each other, and the coarse aggregate has a sufficient width not only in the plurality of spherical portions but also in the connection portion therebetween. Thus, the coarse aggregate for concrete exhibits high strength to compression and tension in any direction. Further, the annular portion protrudes from the surface of the spherical portions so as to surround the outer periphery of the plurality of spherical portions, and thus the adhesive force between the coarse aggregate and a mortar portion of concrete is improved. This also improves strength of the concrete and facilitates uniform dispersion of the coarse aggregate in the fresh concrete. As a result, the concrete prepared by using the coarse aggregate for concrete of the present invention shows significant improvements in compressive strength and tensile strength. In spite of having a shape of sphere or a shape similar to sphere, the protruding annular portion reduces the tendency of rolling of the coarse aggregate, thereby improving handleability thereof. The plurality of spherical portions are surrounded by the annular portion and the width of the connection portion of the spherical portions is equal to or greater than the minimum diameter of the spherical portions.
Thus, the coarse aggregate can be easily molded by press processing using a metal plate with high productivity. The coarse aggregate can be produced at a low cost because a punching step for forming the connection portion can be omitted. Thus, the coarse aggregate is useful as a building material that is consumed in large quantities.
A third mode of the present invention provides a metallic coarse aggregate for concrete, which includes a coarse aggregate body including a spherical cap portion bonded body having two hollow spherical cap portions (hereinafter, sometimes simply referred to as a □spherical cap portion bonded body□) and an annular portion protruding from the surface of the spherical cap portion bonded body so as to surround the outer periphery of the spherical cap portion bonded body, and a plurality of flexible wires penetrating the spherical cap portion bonded body and protruding from the spherical cap portion bonded body or the annular portion. In such a coarse aggregate for concrete, the length of a protrusion portion of the wire (that is, when a part of the wire protruding outside the coarse aggregate body is bent, whether one end of the protrusion portion is held by the coarse aggregate body or both ends of the protrusion portion are held by the coarse aggregate body with the protrusion portion forming a loop, the length of the part of the wire protruding outside the coarse aggregate body when it is extended to a straight line in a state in which the end held by the coarse aggregate body remains held) is 1 to 5 times the maximum diameter of the spherical cap portion bonded body.
Further, the third mode of the present invention provides a method for producing the aforementioned metallic coarse aggregate for concrete in the aspect in which the wires protrude from the annular portion, that is, a method (i) including performing press processing using a metal pipe through which the plurality of flexible wires are passed, to form the spherical cap portion bonded body and the annular portion and to cause the plurality of flexible wires to protrude from the annular portion, and a method (ii) including performing press processing using a metal plate to form a spherical cap portion with flange having a flange at a bottom portion thereof, disposing the bottom portions of two spherical cap portions with flange so as to face each other as well as disposing the plurality of flexible wires between the spherical cap portions with flange so as to cross them, and pressure-bonding the flanges of the two spherical cap portions with flange to each other by press processing as well as holding the plurality of wires between the flanges.
Further, the third mode of the present invention provides a method for producing the coarse aggregate for concrete including a spherical cap portion bonded body having two hollow spherical cap portions and an annular portion protruding from the surface of the spherical cap portion bonded body so as to surround the entire outer periphery of the spherical cap portion bonded body. In such a production method, the spherical cap portion bonded body and the annular portion surrounding the entire outer periphery of the spherical cap portion bonded body are formed by press processing using a metal pipe. This production method has a significance as a production method of the spherical cap portion bonded body itself regardless of the presence/absence of the flexible wire.
Furthermore, the third mode of the present invention provides a metallic coarse aggregate for concrete which includes: a coarse aggregate body for concrete including a spherical cap portion bonded body having two hollow spherical cap portions and an annular portion protruding from the surface of the spherical cap portion bonded body so as to surround the outer periphery of the spherical cap portion bonded body; and a wire which is not adhered to the coarse aggregate body but is wound around the outer surface of the coarse aggregate body.
The third mode of the present invention also provides a metallic coarse aggregate for concrete which includes a coarse aggregate body for concrete including a spherical cap portion bonded body having two hollow spherical cap portions and an annular portion protruding from the surface of the spherical cap portion bonded body so as to surround the outer periphery of the spherical cap portion bonded body, and an outer fitting portion obtained by molding a bent wire into an annular shape so as to externally fit to the coarse aggregate body.
According to the third mode of the present invention, since the spherical cap portion bonded body has a shape of sphere or a shape similar to sphere, the coarse aggregate body of the coarse aggregate for concrete exhibits high strength to compression and tension in any direction. Further, in the coarse aggregate body, since the annular portion protrudes from the surface of the spherical cap portion bonded body so as to surround the outer periphery of the spherical cap portion bonded body, the adhesive force between the coarse aggregate body and a mortar portion of concrete is improved. Further, the spherical cap portion bonded body is made hollow and the plurality of flexible wires protrudes from the coarse aggregate body with the protrusion length of 1 to 5 times the maximum diameter among the diameters of the plurality of spherical cap portion bonded bodies. Thus, these wires are wound around the coarse aggregate body in a step of storage and conveyance of the coarse aggregate, preparation of the mortar, and the like, and the mortar is captured by the wound wires. Thus, the actual specific gravity of the coarse aggregate approaches that of the mortar. As a result, the coarse aggregate is less likely to be sedimented in the fresh concrete and dispersibility thereof in the concrete is improved. Accordingly, the concrete prepared by using the coarse aggregate of the present invention has significant improvements in compressive strength and tensile strength. Further, both in the coarse aggregate for concrete of the present invention in which the wire not adhered to the coarse aggregate body is wound around the outer surface of the coarse aggregate body and in the coarse aggregate for concrete of the present invention which includes the outer fitting portion obtained by molding the bent wire into an annular shape so as to externally fit to the coarse aggregate body, the adhesive force between the coarse aggregate body and a mortar portion of concrete is similarly improved. Furthermore, the coarse aggregate for concrete of the present invention can be produced with high productivity and at a low cost by press processing or the like using a metal plate or a metal pipe, and the wire. Therefore, the coarse aggregate for concrete of the present invention can be useful as a building material that is consumed in large quantities.
A fourth mode of the present invention provides a coarse aggregate for concrete which is obtained by molding a metallic woven net in a hollow shape.
According to the fourth mode of the present invention, when the coarse aggregate for concrete and the mortar are mixed, the mortar intrudes inside the coarse aggregate through a hole of mesh of the metallic woven net which is a metallic mesh material forming the outer surface of the coarse aggregate. Thus, the mortar enters the hole of the mesh of the metallic mesh material, whereby the metallic mesh material and the mortar are integrated with each other in a state of being strongly adhered to each other after the hardening of the fresh concrete. This can prevent the mortar portion integrated with the metallic mesh material from being peeled off from the metallic mesh material and thus being broken, even when a strong load is applied to the concrete. Accordingly, compressive strength, tensile strength, shearing strength, and bending strength of the concrete can be significantly improved.
Hereinafter, a coarse aggregate for concrete of the first mode of the present invention will be described in detail with reference to drawings. Note that, in the present mode, the same reference numerals represent the same or similar constituent elements in each drawing.
In the present example, each spherical cap portion 2 preferably has a shape of spherical cap equal to or greater than a half of the sphere. In the coarse aggregate 1A of the present example, two opposing spherical cap portions 2 have a shape of hemisphere, and the radius R of a sphere of each spherical cap portion 2 is equal to the height H of the spherical cap portion 2. Further, the two spherical cap portions 2 are bonded symmetrically to each other across a bottom surface 2g of each spherical cap portion 2. Accordingly, the outer shape of this spherical cap portion bonded body 3 forms a spherical shape and the outer shape of the coarse aggregate as a whole also forms a substantially spherical shape. Thus, as compared with the coarse aggregate of which the outer shape is a polyhedral shape or an indeterminate three-dimensional shape, the coarse aggregate exhibits high strength to a plane load or a splitting tensile load applied from any direction. Note that, in
In the coarse aggregate 1A, an annular portion 5 having a rectangular shape in plan view, which protrudes from the surface of the spherical cap portion bonded body 3 so as to surround the bottom portion of the spherical cap portion 2, is formed, and thus the spherical cap portion bonded body 3 and the annular portion 5 constitute the coarse aggregate 1A. This annular portion 5 is formed by bonding the rectangular annular flanges 4 formed around the outer peripheries of the bottom surfaces 2g of the respective spherical cap portions. The annular portion 5 is formed over the entire periphery of the spherical cap portion bonded body 3, and thus the coarse aggregate 1A has an approximate Saturn shape. The annular portion 5 protruding in this manner increases the adhesive force between the coarse aggregate 1A and the mortar when the coarse aggregate 1A is mixed with the mortar. Thus, along with the above-described strength improvement effect caused by the outer shape being a substantially spherical shape, the concrete prepared by using this coarse aggregate 1A instead of the conventional coarse aggregate has significant improvements in compressive strength and tensile strength.
Note that the coarse aggregate 1A of the present example includes the annular portion 5 having a shape of square in plan view. However, in the present invention, the outer shape of the annular portion 5 in plan view is not limited to the square, and it may be a rectangle.
As shown in
In order to allow the fresh concrete in which the coarse aggregate 1A is blended to be pumped through a hose by pressure feeding, when the radius of the sphere of the spherical cap portion 2 is represented by R and the protrusion length (maximum length) of the annular portion 5 is represented by L, the maximum diameter ((R+L)×2) of the spherical cap portion bonded body 3 is preferably set to be approximately the same size as that of crushed gravel or stones of the conventional coarse aggregate. Specifically, the maximum diameter ((R+L)×2) of the coarse aggregate 1A is preferably set to be within a range of particle size and particle shape defined by JIS A 5308. In general, it is preferable that the diameter 2R of the sphere of the spherical cap portion 2 be set to be 10 mm to 30 mm, and the protrusion length L of the annular portion 5 be set to be ⅖ to 1 time the radius R of the sphere of the spherical cap portion 2. On the other hand, if the protrusion length L of the annular portion 5 is too small, when the annular portion 5 is formed by bonding to each other the flanges 4 formed outside the bottom portion of the spherical cap portion 2, it is difficult to strongly bond the flanges to each other. Further, when formation of the spherical cap portion bonded body by pressure-bonding of the spherical cap portions and insertion of the wire are not performed at the same time in the production method of the coarse aggregate, the spherical cap portion bonded body 3 is caused to excessively easily roll and thus handleability is deteriorated.
In the first mode of the present invention, the outer shape of the spherical cap portion bonded body 3 is a shape of sphere or a shape similar to sphere, and thus the height H of the spherical cap portion 2 is preferably equal to or greater than the radius R of the sphere of the spherical cap portion 2. In the coarse aggregate 1A of the present example, the height H of the spherical cap portion 2 is equal to the radius R of the sphere of the spherical cap portion 2.
The thickness t of the spherical cap portion 2 can be determined in accordance with, for example, the kind of metal constituting the coarse aggregate 1A, the formation method of the shape of the spherical cap portion, and the use of the concrete prepared by using the coarse aggregate. For example, when the coarse aggregate is used in heavyweight concrete for radiation shield, the specific gravity of the coarse aggregate is preferably increased by increasing the thickness t of the spherical cap portion 2. There is no particular upper limitation on the thickness t. In this case, the spherical cap portion 2 can be produced by hot press.
On the other hand, when the coarse aggregate is used for the normal concrete and the spherical cap portion is formed by cold press, the spherical cap portion 2 having an excessively large thickness t makes it difficult to form the spherical cap portion by press processing, while the spherical cap portion 2 having an excessively small thickness t causes insufficient strength even when the coarse aggregate is used for the normal concrete. Thus, the thickness t of the spherical cap portion 2 is preferably set to be 1 mm to 6 mm.
As the metal constituting the coarse aggregate 1A of the first mode of the present invention, iron, aluminum, titanium, copper, stainless steel, and the like can be mentioned, and the metal can be selected in accordance with the use of the concrete. For example, when the coarse aggregate is included in the heavyweight concrete used for shielding radiation in a nuclear facility or the like, the metal with high density such as iron is preferably used from the viewpoint of shielding X rays, γ rays, and the like. In order to perform production, conveyance, and the like of the coarse aggregate 1A itself or various concrete products including the coarse aggregate 1A by using an electromagnet, the coarse aggregate is preferably formed from a magnetic substance such as iron.
As a production method of the coarse aggregate 1A, first, the spherical cap portion 2 having the flange 4 at its bottom portion (that is, spherical cap portion with flange) is formed by press processing using a metal plate. Next, as shown in
The coarse aggregate of the first mode of the present invention is made of metal and can take various shapes as long as it includes the spherical cap portion bonded body having two spherical cap portions and the rectangular annular portion formed around the outer periphery of the spherical cap portion bonded body. For example, as shown in
In a coarse aggregate 1C shown in
Note that the depth d of the recessed portion 3a is preferably set to be ⅓ to ½ the radius R of the spherical cap portion bonded body 3.
In a coarse aggregate 1D shown in
In a coarse aggregate 1E shown in
In the first mode of the present invention, in order to improve the adhesion of mortar, molten metal droplets generated by a sputtering phenomenon of various welding types are welded to a part or the whole, preferably the whole, of the surface of the coarse aggregate body, so that the surface can be roughened by the metal particle welded to the surface. According to this method, as compared with a case where the surface of the coarse aggregate is roughened simply by irradiating the surface with electron beam or the like, the metal droplets generated by melting an electrode bar are adhered to the surface of the coarse aggregate body without reducing the thickness of the coarse aggregate body, and thus the adhesion of mortar to the coarse aggregate body can be improved without reducing the strength of the coarse aggregate body.
In particular, it is preferable that arc discharge be performed using an electrode preferably with heating, and the molten metal droplets generated from the electrode be welded to the surface of the coarse aggregate body under heating. In this manner, as seen in the metal surface shown in
Further, instead of welding of the molten metal droplets of the electrode bar to the coarse aggregate body by arc discharge as described above, welding of the molten metal droplets of the electrode bar may be performed by applying arc discharge or the like in advance to a metal plate, a metal pipe, or a metal bar to be used at the time of producing the coarse aggregate.
Note that the modified aspects of the first mode of the present invention described above can be appropriately combined with one another.
The coarse aggregate for concrete of the first mode of the present invention can partially or wholly replace the coarse aggregate in the blending composition of the conventional concrete. As a preferable application example of the coarse aggregate for concrete of the first mode of the present invention, as a concrete precast product, for example, the hollow coarse aggregate of the first mode of the present invention can be used to produce a light-weight ferroconcrete plate that is highly resistant to compression and tension. The coarse aggregate for concrete can be preferably used for a concrete construction without a reinforcing bar (e.g., a dam wall, a road set directly on the ground, a mat foundation for a construction, and a paved place). As a specialized application example, the coarse aggregate for concrete can be preferably used for a ferroconcrete floor slab for an express-highway set at a position apart from the ground, or the like. Further, when the coarse aggregate for concrete of the first mode of the present invention is constituted from a magnetic material, conveyance, installation, and removal of a panel can be performed through attraction to an electromagnet, and thus workability is improved.
Hereinafter, a coarse aggregate for concrete of the second mode of the present invention will be described in detail with reference to drawings. Note that, in the present mode, the same reference numerals represent the same or similar constituent elements in each drawing.
In the coarse aggregate 1A, the annular portion 5 protruding from the surface of the spherical portions 3 so as to surround the outer periphery of two spherical portions 3 on the plane including the bottom surface 2g of each spherical cap portion 2 is formed. As shown in
The two spherical portions have an equal diameter D, and the width W of the coarse aggregate in a connection portion P of the two spherical portions 3 on the plane formed by the outer edge of the annular portion 5 is equal to or greater than the diameter D of the spherical portions 3. Here, in a case where the two spherical portions 3 are away from each other as shown in
Further, according to this coarse aggregate 1A, the annular portion 5 increases the adhesive force between the coarse aggregate 1A and the mortar when the coarse aggregate 1A and the mortar are mixed. Thus, along with the above strength improvement effect caused by the two spherical portions 3 included in the coarse aggregate 1A, the concrete prepared by using this coarse aggregate 1A instead of the conventional coarse aggregate has significant improvements in compressive strength and tensile strength.
Note that, although two spherical portions have the equal diameter in the coarse aggregate 1A of the present example, when two spherical portions have a different diameter, the width W of the coarse aggregate in the connection portion P is equal to or greater than the smaller diameter. Further, in the coarse aggregate 1A of the present example, the outer shape of the annular portion 5 in plan view is a rectangular shape having rounded corners. However, the outer shape of the annular portion 5 in the present invention is not limited thereto, and, for example, the annular portion 5 may have a rectangular shape as seen in a coarse aggregate 1A′ shown in
In order to allow the fresh concrete in which the coarse aggregate 1A is blended to be pumped through a hose by pressure feeding, the maximum diameter of the coarse aggregate 1A is preferably set to be approximately the same size as that of gravel or crushed stones of the conventional coarse aggregate. Specifically, the maximum diameter of the coarse aggregate 1A is preferably set to fall within a range of particle size and particle shape defined by JIS A 5308. For this purpose, in general, the diameter D of the spherical portion 3 is preferably set to be 10 to 30 mm and the protrusion length L of the annular portion 5 in the radial direction of the sphere of the spherical cap portion 2 is preferably set to be ⅖ to 1 time the radius R of the sphere of the spherical cap portion 2. On the other hand, when the protrusion length L of the annular portion 5 is too small, the adhesive force between the coarse aggregate and the mortar is reduced and the coarse aggregate 1A is caused to excessively easily roll. Thus, handleability is deteriorated. Further, when the annular portion 5 is formed by bonding to each other the flanges 4 formed outside the bottom portions of the spherical cap portions 2, if the protrusion length L of the annular portion 5 (that is, the protrusion length of the flange 4) is too small, it becomes difficult to strongly bond the flanges 4 to each other.
In the coarse aggregate 1A of the present example, the height H of the spherical cap portion 2 is equal to the radius R of the sphere of the spherical cap portion 2. In the second mode of the present invention, the height H of the spherical cap portion 2 is preferably set to be equal to or greater than the radius R of the sphere of the spherical cap portion 2 in order to allow the outer shape of the coarse aggregate 1A to include the spherical portion 3 having a shape of sphere or a shape similar to sphere. On the other hand, when the height H is too high, it sometime becomes difficult to pump the concrete through a hose by pressure feeding. Thus, the height H of the spherical cap portion 2 is preferably set to be 1.5 times or less the radius R of the sphere of the spherical cap portion 2.
In the second mode of the present invention, the thickness t of the spherical cap portion 2 (that is, a thickness of the spherical portion 3) can be determined in accordance with, for example, the kind of metal constituting the coarse aggregate 1A, the formation method of the shape of the spherical cap portion, and the use of the concrete prepared by using the coarse aggregate. For example, when the coarse aggregate is used in heavyweight concrete for radiation shield, the specific gravity of the coarse aggregate is preferably increased by increasing the thickness t of the spherical cap portion 2. There is no particular upper limitation on the thickness t. A hollow portion may not be substantially formed inside the coarse aggregate. In this case, the spherical cap portion 2 can be produced by hot press.
On the other hand, when the coarse aggregate is used for the normal concrete and the spherical cap portion is formed by cold press, the spherical cap portion 2 having an excessively large thickness t makes it difficult to form the spherical cap portion by press processing, while the spherical cap portion 2 having an excessively small thickness t causes insufficient strength even when the coarse aggregate is used for the normal concrete. Thus, the thickness t of the spherical cap portion 2 is set to be preferably 1 to 6 mm, more preferably 2 to 4 mm.
As the metal constituting the coarse aggregate 1A of the second mode of the present invention, iron, aluminum, titanium, copper, stainless steel, and the like can be mentioned, and the metal can be selected in accordance with the use of the concrete. For example, when the coarse aggregate is included in the heavyweight concrete used for shielding radiation in a nuclear facility or the like, the metal with high density such as iron is preferably used from the standpoint of shielding X rays, γ rays, and the like. In order to perform production, conveyance, and the like of the coarse aggregate 1A itself or various concrete products including the coarse aggregate 1A by using an electromagnet, the coarse aggregate is preferably formed from a magnetic substance such as iron.
The coarse aggregate 1A of the present example can be easily produced through press processing using a metal plate as shown in
Welding of the flanges 4 is preferably performed over the entire periphery of the flanges 4. On the other hand, the flanges 4 may be bonded to each other by caulking instead of welding.
Note that, in the second mode of the present invention, the production method of the coarse aggregate is not limited to press processing using a metal plate, and, as described below, the coarse aggregate can be produced by press processing using a metal pipe or a metal bar, or the like.
The coarse aggregate of the second mode of the present invention is made of metal, includes a plurality of the spherical portions and the annular portion protruding from the surface of the spherical portions so as to surround the outer periphery of the plurality of spherical portions, and can be formed in various shapes in which the width of the coarse aggregate in the connection portion of the spherical portions on the plane formed by the outer edge of the annular portion is equal to or greater than the minimum diameter of the spherical portions.
For example, in the coarse aggregate 1A shown in
The width W of the coarse aggregate 1C in the connection portion P when the spherical portions are directly connected to each other is, as shown in
In a coarse aggregate 1D shown in
In a coarse aggregate 1E shown in
A coarse aggregate 1F shown in
A coarse aggregate 1G shown in
A coarse aggregate 1H shown in
By using the similar method, the coarse aggregate in which three or more spherical portions 3 are directly connected may be molded using a metal pipe, and three or more spherical portions may be disposed side by side via the annular portion 5.
Instead of the small piece 11 obtained by cutting the metal pipe, a solid coarse aggregate having a similar outer shape to that of the coarse aggregate obtained by press molding using a metal pipe can be produced by performing hot press with the similar die using a small piece obtained by cutting a metal bar, or a metal plate. For example, a coarse aggregate 1I shown in
In the coarse aggregate of the second mode of the present invention, in any of the aspects described above, a wire can be protruded from the spherical portion in order to improve bonding strength between the coarse aggregate and the mortar.
A coarse aggregate 1J shown in
Further, when the wire having a small diameter is used, for example, in the stirring step of the fresh concrete after producing the coarse aggregate including the wire, as shown in
The coarse aggregate to which the wires 13a are attached may be produced, as shown in
When the wire is attached to the coarse aggregate body including the spherical portion 3 and the annular portion 5, for example, as seen in a coarse aggregate 1L shown in
Further, as seen in a coarse aggregate 1M shown in FIG. 19b, the wires 13a may simply be wound from the outside of the coarse aggregate body including the spherical portion 3 and the rectangular annular portion 5. These wires 13a do not penetrate the spherical portion 3 or adhere to the spherical portion 3. When the wires 13a are wound around the coarse aggregate body from the beginning, the mortar tends to adhere to the coarse aggregate 1M as soon as the coarse aggregate 1M is mixed to the mortar, which improves dispersibility of the coarse aggregate 1M in the mortar and strength of the concrete. On the other hand, once the wires 13a are wound around the coarse aggregate body, the wires 13a do not fall off from the coarse aggregate body at the time of storage and conveyance of the coarse aggregate 1M.
In any of the coarse aggregates 1A to 1M described above, surface unevenness can be created on the coarse aggregate by emboss processing in order to improve adhesion of mortar in the concrete. Further, molten metal droplets generated by a sputtering phenomenon of various welding types are welded to a part or the whole, preferably the whole, of the surface of these coarse aggregates, so that the surface can be roughened by the metal particles welded to the surface. According to this method, as compared with a case where the surface of the coarse aggregate is roughened simply by irradiating the surface with electron beam or the like, the metal droplets generated by melting the electrode bar adhere to the surface of the coarse aggregate body without reducing the thickness of the coarse aggregate body. Thus, the adhesion of mortar to the coarse aggregate body can be improved without reducing the strength of the coarse aggregate body.
In particular, it is preferable that arc discharge be performed using an electrode preferably with heating, and the molten metal droplets generated from the electrode be welded to the surface of the metal constituting the coarse aggregate under heating. In this manner, as seen in the metal surface shown in
Note that welding of the molten metal droplets melted from the electrode bar to the surface of the coarse aggregate by the arc discharge can be performed with high productivity and at a low cost.
Further, instead of performing welding of the molten metal droplets to the coarse aggregate by the arc discharge as described above, welding of the molten metal droplets may be performed by applying the arc discharge or the like in advance to a metal plate, a metal pipe, or a metal bar to be used at the time of producing the coarse aggregate.
The coarse aggregate for concrete of the second mode of the present invention can partially or wholly replace the coarse aggregate in the blending composition of the conventional concrete. As a preferable application example of the coarse aggregate for concrete of the second mode of the present invention, as a concrete precast product, for example, the hollow coarse aggregate of the present invention can be used to produce a light-weight ferroconcrete plate that is highly resistant to compression and tension. Further, it can be preferably applied to a concrete structure not including a reinforcing bar (e.g., a dam wall, a road directly laid on the ground surface, a mat foundation for a construction, and a paved square). As a specialized application example, it can be preferably applied to a ferroconcrete floor slab for a highway constructed at a position away from the ground surface, or the like. When the coarse aggregate for concrete of the present invention is formed from iron, in particular, when it is made solid, it can be useful as the coarse aggregate for heavyweight concrete used for shielding radiation in a nuclear facility or the like. Further, when the coarse aggregate for concrete of the second mode of the present invention is constituted from a magnetic material, conveyance, installation, and removal of a panel can be performed through attraction to an electromagnet, and thus workability is improved.
Hereinafter, a coarse aggregate for concrete of the third mode of the present invention will be described in detail with reference to drawings. Note that, in the present mode, the same reference numerals represent the same or similar constituent elements in each drawing.
In the present example, each spherical cap portion 2 preferably has a shape of spherical cap equal to or greater than a half of the sphere. In the coarse aggregate 1A of the present example, two opposing spherical cap portions 2 have a shape of hemisphere and the radius r of a sphere of each spherical cap portion 2 is equal to the height h of the spherical cap portion 2. Further, the two spherical cap portions 2 are bonded symmetrically to each other across a bottom surface 2g of each spherical cap portion 2. Accordingly, the outer shape of this spherical cap portion bonded body 3 forms a spherical shape and the outer shape of the coarse aggregate as a whole also forms a substantially spherical shape. Thus, as compared with the coarse aggregate of which the outer shape is a polyhedral shape or an indeterminate three-dimensional shape, the coarse aggregate exhibits high strength to a plane load or a splitting tensile load applied from any direction. Note that, in
In the coarse aggregate 1A, an annular portion 5 protruding from the surface of the spherical cap portion bonded body 3 so as to surround the bottom portion of the spherical cap portion 2 is formed, and thus the coarse aggregate body 1A□ is constituted by the spherical cap portion bonded body 3 and the annular portion 5. This annular portion 5 is formed by bonding the annular flanges 4 formed around the outer peripheries of the bottom surfaces 2g of the respective spherical cap portions. The annular portion 5 is formed over the entire periphery of the spherical cap portion bonded body 3, and thus the coarse aggregate 1A has an approximate Saturn shape. The annular portion 5 increases the adhesive force between the coarse aggregate 1A and the mortar when the coarse aggregate 1A is mixed with the mortar. Thus, along with the above-described strength improvement effect caused by the outer shape being a substantially spherical shape, the concrete prepared by using this coarse aggregate 1A instead of the conventional coarse aggregate has significant improvements in compressive strength and tensile strength.
Note that the coarse aggregate 1A of the present example includes the annular portion 5 having an annular shape. However, in the third mode of the present invention, the outer shape of the annular portion 5 in plan view is not limited to the circle, and it may be an oval shape, an irregular annular outer shape, or a rectangle. As a coarse aggregate 1B shown in
A plurality of flexible wires 13a penetrate the spherical cap portion bonded body 3, so that the plurality of wires 13a protrude from the coarse aggregate body 1A′, more specifically from the ends of the annular portion 5. It is preferable that the length L2 of the protrusion portion of the wire 13a be 1 to 5 times, specifically 1 to 3 times the maximum diameter L3 of the spherical cap portion bonded body 3. Here, the length of the protrusion portion of the wire 13a is the length when the wire which was bent is extended in a substantially straight line shape. When one coarse aggregate for concrete has a plurality of spherical cap portion bonded bodies as described below, the maximum diameter of the spherical cap portion bonded body 3 means the maximum diameter among them.
Since the length L2 of the protrusion portion of the wire 13a is not less than 1 time the maximum diameter L3 of the spherical cap portion bonded body 3, the wires 13a are wound around the coarse aggregate body as shown in
The number of wires 13a protruding from one end of the coarse aggregate body 1A′ is preferably 2 to 5.
It is not always necessary that all of the plurality of wires protruding from the coarse aggregate body have a diameter of 1 to 5 times the maximum diameter L3 of the spherical cap portion bonded body 3, and there may be a protrusion portion having a length outside this range. However, it is preferable that the protrusion portions of all the wires have such a length. Here, □the length of the protrusion portion of the wire□ can be defined as □when a part of the wire protruding outside the coarse aggregate body is bent, whether one end of the protrusion portion is held by the coarse aggregate body or both ends of the protrusion portion are held by the coarse aggregate body with the protrusion portion forming a loop, the length of the part of the wire protruding outside the coarse aggregate body when it is extended to a straight line in a state in which the end held by the coarse aggregate body remains held.□
As the wire 13a, a wire of gauge No. 16 or more and 21 or less, which has a small diameter and is easily bendable, is preferable, and a wire of gauge No. 20 or more is particularly preferable. When a wire having a small diameter and being easily bendable is used, the wires 13a are easily bent by applying a force to the wires 13a even at the time of attaching the wires 13a to the coarse aggregate body 1A′ including the spherical cap portion bonded body 3 and the annular portion 5, storing and conveying the coarse aggregate after the attachment, and preparing the fresh concrete including the coarse aggregate 1A. Thus, the wires 13a and the coarse aggregate body are not necessarily strongly fixed to each other by welding or the like, and the wires 13a are only required to be pressure-bonded to the coarse aggregate body to such an extent that the wires 13a do not fall off from the coarse aggregate body. This can reduce time and a cost required for attaching the wires 13a.
Further, when the wires having a small diameter and being easily bendable are used, for example, in the stirring step of the fresh concrete, as shown in
On the other hand, a wire having a diameter larger than gauge No. 16, and preferably a wire having a large diameter of gauge No. 8 or more and gauge No. 12 or less may be used together with the wire having a small diameter. In this case, it is preferable that the tip end of the wire having a large diameter be bent into a key shape, a C shape or the like. The large-diameter wire does not wind around the coarse aggregate body 1A′ as shown in
In order to allow the fresh concrete in which the coarse aggregate 1A is blended to be pumped through a hose by pressure feeding, when the radius of the sphere of the spherical cap portion 2 is represented by r and the protrusion length of the annular portion 5 is represented by L, the maximum diameter ((r+L)×2) of the spherical cap portion bonded body 3 is preferably set to be approximately the same size as that of crushed gravel or stones of the conventional coarse aggregate. Specifically, the maximum diameter ((r+L)×2) of the coarse aggregate 1A is preferably set to be within a range of particle size and particle shape defined by JIS A 5308. In general, it is preferable that the diameter 2r of the sphere of the spherical cap portion 2 be set to be 10 mm to 30 mm, and the protrusion length L of the annular portion 5 be set to be ⅖ to 1 time the radius r of the sphere of the spherical cap portion 2. On the other hand, if the protrusion length L of the annular portion 5 is too small, when the annular portion 5 is formed by bonding to each other the flanges 4 formed outside the bottom portion of the spherical cap portion 2, it is difficult to strongly bond the flanges to each other. Further, when formation of the spherical cap portion bonded body by pressure-bonding of the spherical cap portions and insertion of the wire are not performed at the same time in the production method of the coarse aggregate, the spherical cap portion bonded body 3 is caused to excessively easily roll and thus handleability is deteriorated.
In the third mode of the present invention, the outer shape of the spherical cap portion bonded body 3 is a shape of sphere or a shape similar to sphere, and thus the height h of the spherical cap portion 2 is preferably equal to or greater than the radius r of the sphere of the spherical cap portion 2. In the coarse aggregate 1A of the present example, the height h of the spherical cap portion 2 is equal to the radius r of the sphere of the spherical cap portion 2. On the other hand, if the height h is too large, the maximum length of the spherical cap portion bonded body 3 becomes long, which may hinder pumping of concrete through a hose by pressure feeding. Therefore, the height h of the spherical cap portion 2 is preferably 1.8 times or less the radius r of the sphere of the spherical cap portion 2.
The thickness t of the spherical cap portion 2 can be determined in accordance with, for example, the kind of metal constituting the coarse aggregate 1A, the formation method of the shape of the spherical cap portion, and the use of the concrete prepared by using the coarse aggregate. For example, when the coarse aggregate is used in heavyweight concrete for radiation shield, the specific gravity of the coarse aggregate is preferably increased by increasing the thickness t of the spherical cap portion 2. There is no particular upper limitation on the thickness t. In this case, the spherical cap portion 2 can be produced by hot press.
On the other hand, when the coarse aggregate is used for the normal concrete and the spherical cap portion is formed by cold press, the spherical cap portion 2 having an excessively large thickness t makes it difficult to form the spherical cap portion by press processing, while the spherical cap portion 2 having an excessively small thickness t causes insufficient strength even when the coarse aggregate is used for the normal concrete. Thus, the thickness t of the spherical cap portion 2 is preferably set to be 1 mm to 6 mm.
As the metal constituting the coarse aggregate 1A of the third mode of the present invention, iron, aluminum, titanium, copper, stainless steel, and the like can be mentioned, and the metal can be selected in accordance with the use of the concrete. For example, when the coarse aggregate is included in the heavyweight concrete used for shielding radiation in a nuclear facility or the like, the metal with high density such as iron is preferably used from the viewpoint of shielding X rays, γ rays, and the like. In order to perform production, conveyance, and the like of the coarse aggregate 1A itself or various concrete products including the coarse aggregate 1A by using an electromagnet, the coarse aggregate is preferably formed from a magnetic substance such as iron.
As a production method of the coarse aggregate 1A, first, the spherical cap portion 2 having the flange 4 at its bottom portion is formed by press processing using a metal plate. Next, as shown in
The coarse aggregate of the third mode of the present invention is made of metal and can take various shapes as long as it includes the spherical cap portion bonded body having two spherical cap portions, the annular portion formed around the outer periphery of the spherical cap portion bonded body, and the plurality of flexible wires penetrating the spherical cap portion bonded body and protruding from the spherical cap portion bonded body or the annular portion. For example, as shown in
When the wire is to be protruded in the coarse aggregate, the wires 13a penetrating the spherical cap portion bonded body 3 may be protruded from the surface of the spherical cap portion bonded body 3 like a coarse aggregate 1E as shown in
Even when the wire is protruded from the surface of the spherical cap portion bonded body 3, the spherical cap portion bonded bodies 3 having a plurality of annular portions 5 may be adjacent to each other like a coarse aggregate 1F shown in
In addition, as shown in
A coarse aggregate 1H shown in
A coarse aggregate body 1I′ of a coarse aggregate 1I shown in
In producing the coarse aggregate using the metal pipe, as shown in
In addition, a method for producing a coarse aggregate body including a spherical cap portion bonded body and an annular portion by pressing a metal pipe as shown in
On the other hand, in a coarse aggregate 1K shown in
A coarse aggregate 1L shown in
In particular, in this coarse aggregate 1L, the shape of the annular portion 5 in plan view is rectangular, and each side of the rectangle is preferably recessed inward under the influence of the press of the spherical cap portion. The deviation of the wires 13a is prevented when the wires 13a are wound around the coarse aggregate body 1L′, so that the wires 13a can be easily wound. Thus, when the wires 13a are wound around the coarse aggregate body 1L′ in this manner, it is not necessary for the wires 13a to be sandwiched between the flanges 4 constituting the annular portion 5, to pass a through-hole that is opened in the coarse aggregate body 1L′, or to be bonded to the coarse aggregate body 1L′. Accordingly, the coarse aggregate can be easily produced.
The gauge number of the wire to be wound around the coarse aggregate body 1L′ is preferably gauge No. 8 to gauge No. 20, and more preferably gauge No. 12 to gauge No. 20.
In a coarse aggregate 1M shown in
The third mode of the present invention can take various aspects even for the coarse aggregate body. In a coarse aggregate 1N shown in
In a coarse aggregate 1O shown in
In a coarse aggregate 1P shown in
Note that the depth d of the recessed portion 3a is preferably set to be ⅓ to ½ times the radius r of the spherical cap portion bonded body 3.
A coarse aggregate body 1Q′ shown in
In a coarse aggregate body 1R′ shown in
In a coarse aggregate body 1S′ shown in
In a coarse aggregate body 1T′ shown in
In a coarse aggregate body 1U′ shown in
In a coarse aggregate body 1V′ shown in
As described above, the coarse aggregate bodies shown in
In the third mode of the present invention, in order to improve the adhesion of mortar, molten metal droplets generated by a sputtering phenomenon of various welding types are welded to a part or the whole, preferably the whole, of the surface of the coarse aggregate body, so that the surface can be roughened by the metal particles welded to the surface. According to this method, as compared with a case where the surface of the coarse aggregate is roughened simply by irradiating the surface with electron beam or the like, the metal droplets generated by melting an electrode bar are adhered to the surface of the coarse aggregate body without reducing the thickness of the coarse aggregate body, and thus the adhesion of mortar to the coarse aggregate body can be improved without reducing the strength of the coarse aggregate body.
In particular, it is preferable that arc discharge be performed using an electrode preferably with heating, and the molten metal droplets generated from the electrode be welded to the surface of the coarse aggregate body under heating. In this manner, as seen in the metal surface shown in
Further, instead of welding of the molten metal droplets of the electrode bar to the coarse aggregate body by arc discharge as described above, welding of the molten metal droplets of the electrode bar may be performed by applying arc discharge or the like in advance to a metal plate, a metal pipe, or a metal bar to be used at the time of producing the coarse aggregate.
Note that the modified aspects of the third mode of the present invention described above can be appropriately combined with one another.
The coarse aggregate for concrete of the third mode of the present invention can partially or wholly replace the coarse aggregate in the blending composition of the conventional concrete. As a preferable application example of the coarse aggregate for concrete of the third mode of the present invention, as a concrete precast product, for example, the hollow coarse aggregate of the third mode of the present invention can be used to produce a light-weight ferroconcrete plate that is highly resistant to compression and tension. The coarse aggregate for concrete can be preferably used for a concrete construction without a reinforcing bar (e.g., a dam wall, a road set directly on the ground, a mat foundation for a construction, and a paved place). As a specialized application example, the coarse aggregate for concrete can be preferably used for a ferroconcrete floor slab for an express-highway set at a position apart from the ground, or the like. Further, when the coarse aggregate for concrete of the present invention is constituted from a magnetic material, conveyance, installation, and removal of a panel can be performed through attraction to an electromagnet, and thus workability is improved.
Hereinafter, a coarse aggregate for concrete of the fourth mode of the present invention will be described in detail with reference to drawings. Note that, in the present mode, the same reference numerals represent the same or similar constituent elements in each drawing.
As to the size of the coarse aggregate for concrete in the fourth mode of the present invention, in order to allow the fresh concrete in which the coarse aggregate 1A is blended to be pumped through a hose by pressure feeding, the maximum diameter of the coarse aggregate for concrete is preferably set to be approximately the same size as that of gravel or crushed stones of the conventional coarse aggregate. Specifically, the maximum diameter of the coarse aggregate 1A including the protruded portions 2 and the flange 3 is preferably set to be within a range of particle size and particle shape defined by JIS A 5005 and JIS A 5308.
As the metallic mesh material in the fourth mode of the present invention, a woven net such as a plain weave and a twill weave, a lath net, a welding net, a perforated metal, a ring mesh, or the like can be used. The outer shape of the predetermined coarse aggregate may be formed by molding a flat metallic mesh material, or the metallic mesh material that forms the outer shape of the predetermined coarse aggregate may be formed by bonding individual annular materials together.
The coarse aggregate 1A for concrete according to the present example uses a woven net. The woven net used allows the mortar to be more likely to enter the holes of the mesh as compared with the case where perforated metal having the same aperture ratio is used, and the adhesive force of the mortar to the metallic mesh material can be further improved. On the other hand, the perforated metal used facilitates the press molding of a metallic mesh material and welding of metallic mesh materials together.
Even when any kind of metallic mesh material is used, it is preferable that the mesh spacing or opening diameter be usually 4 mm to 10 mm from the viewpoint of causing the mortar to easily enter the inside of the coarse aggregate 1A for concrete so that the mortar is contained in the metallic mesh material and integrated thereto when the coarse aggregate 1A for concrete is mixed with the mortar. On the other hand, the weight of the concrete may be reduced by not allowing the mortar to completely enter the inside of the coarse aggregate and forming a cavity inside the coarse aggregate. In this case, the opening diameter of the mesh may be selected so that when the coarse aggregate 1A for concrete is mixed with the mortar, the opening of the mesh becomes the resistance for the mortar entering the inside of the coarse aggregate.
In the fourth mode of the present invention, the wire diameter of the wire forming the metallic mesh material is determined according to the type of metal forming the wire from the viewpoint that it can be easily formed into a predetermined shape. For example, in the case of an iron wire used, the wire diameter is preferably 0.8 mm to 6 mm, more preferably 1 mm to 3 mm. It should be noted that a mesh material using a wire having a large wire diameter cannot be configured as a woven net, but is formed as a welded net.
Further, in the fourth mode of the present invention, a core material can be put inside the coarse aggregate as described below. When the core material is not put inside the coarse aggregate 1A and only the metallic mesh material is used as the constituent material of the coarse aggregate 1A as in this example, it is preferable to use a wire that is hard and thick as compared with the case where the core material is put inside the coarse aggregate 1A in order to substantially maintain the shape of the coarse aggregate 1A and prevent the coarse aggregate 1A from floating even when the coarse aggregate 1A is stirred in fresh concrete.
Examples of the types of metal constituting the metallic mesh material may include iron, aluminum, titanium, copper, and stainless steel, which can be selected according to the use of concrete. For example, from the viewpoint of making it possible to use a magnet during the production or conveyance of various concrete products including the coarse aggregate 1A for concrete, it is preferable that the constituent metal of the metallic mesh material be a magnetic material such as iron.
As a production method of the coarse aggregate 1A for concrete shown in
The coarse aggregate for concrete of the fourth mode of the present invention may have a core material thereinside. For example, a coarse aggregate 1B for concrete shown in
Further, it is preferable to use a magnetic material such as an iron material because a magnet can be used in the step of conveying the coarse aggregate and the concrete product using such a coarse aggregate.
The coarse aggregate for concrete of the fourth mode of the present invention can include various aspects. For example, a coarse aggregate 1C for concrete shown in
In a coarse aggregate 1D for concrete shown in
In a coarse aggregate 1E for concrete shown in
In a coarse aggregate 1F for concrete shown in
A coarse aggregate 1G for concrete shown in
A coarse aggregate 1H for concrete shown in
A coarse aggregate 1I for concrete shown in
A coarse aggregate 1J for concrete shown in
A coarse aggregate 1K for concrete shown in
A coarse aggregate 1L for concrete shown in
A coarse aggregate 1M for concrete shown in
A coarse aggregate 1N for concrete shown in
As described above, the coarse aggregate for concrete of the fourth mode of the present invention is characterized in that the entire outer surface is formed by the metallic mesh material, and thus it can take various outer shapes.
The coarse aggregate for concrete of the fourth mode of the present invention can partially or wholly replace the coarse aggregate in the blending composition of the conventional concrete. As a preferable application example of the coarse aggregate for concrete of the fourth mode of the present invention, as a concrete precast product, for example, the hollow coarse aggregate of the present invention can be used to produce a light-weight ferroconcrete plate that is more resistant to tension and bending than the conventional one. Further, it can be preferably applied to a concrete structure not including a reinforcing bar (e.g., a dam wall, a road directly laid on the ground surface, a mat foundation for a construction, and a paved square). As a specialized application example, it can be preferably applied to a ferroconcrete floor slab for a highway constructed at a position away from the ground surface, or the like. The coarse aggregate for concrete of the fourth mode of the present invention in which the core material is made of iron and the ratio occupied by the core material is increased can be useful as a coarse aggregate for heavyweight concrete used for shielding radiation in a nuclear facility or the like. Further, when the metallic mesh material or the core material is constituted from a magnetic material, conveyance, installation, and removal of a concrete panel can be performed through attraction to an electromagnet, and thus workability is improved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-069447 | Mar 2019 | JP | national |
| 2019-075574 | Apr 2019 | JP | national |
| 2019-128598 | Jul 2019 | JP | national |
| 2019-128625 | Jul 2019 | JP | national |
| 2019-172347 | Sep 2019 | JP | national |
| 2019-234290 | Dec 2019 | JP | national |
| 2020-000931 | Jan 2020 | JP | national |
| 2020-000999 | Jan 2020 | JP | national |
