JP2004285592A - Embedding material for concrete slab and concrete slab using embedding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a cast-in-place hollow concrete slab avoiding an upward bend of an embedding material 20 due to the buoyancy, and having a covering thickness and a hollow ratio as a design value. <P>SOLUTION: In a concrete slab formed by embedding an embedding material 20 together with a fixing implement 40 in the cast-in-place concrete 33, recessed grooves 2, 3 are formed along the ridge lines of the top and bottom of the embedding material body 10 constituted by two or more unit embedding bodies 1 continuing in the longitudinal direction, and reinforcing sash wooden bars 5, 6 are integrally inserted into the recessed grooves 2, 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an embedding material for a concrete slab and a concrete slab having the embedding material.
[0002]
[Prior art]
Conventionally, a concrete slab in which a synthetic resin foam or a lightweight metal tube is embedded in a concrete layer is known. For example, Patent Literature 1 (Japanese Patent Publication No. 2-41614) discloses a lightweight embedding made of a synthetic resin foam in a state of being lifted by a required cover thickness from the surface of a temporarily-molded temporary mold frame. The concrete is fixed using appropriate fixing tools, the necessary reinforcement is provided there, and the cast-in-place concrete is cast over the embedded material so that the required cover thickness can be obtained. A slab is described. The so-called hollow concrete slab of this configuration can be reduced in weight by the amount of the embedding material, while the required stiffness due to the presence of concrete for the thickness of the concrete slab exists between the embedding materials. Is also secured.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 2-41614
[Problems to be solved by the invention]
When constructing a concrete slab with the above configuration, after fixing the embedding material to the required position on the demolding temporary formwork by using an appropriate fixture, cast-in-place concrete will be poured. Since the batting material has a lower specific gravity than the concrete to be cast, it receives buoyancy from the cast concrete. When the embedding material is lifted by the buoyancy, the cover thickness with the upper surface of the slab is reduced, and when the upper end muscle runs immediately above the embedding material, it comes into contact with the upper end muscle.
[0005]
In order to prevent such a situation from occurring, in the conventional concrete slab, a large number of fixtures for fixing the embedding material are arranged at narrow intervals, and the amount of work on site is increased. Further, when the embedding material is a molded article of a foamed resin, the length of one embedding material is limited in relation to a molding die, and the length is usually about 1 m at most. For this reason, when making a concrete slab having a long span (currently, about 8 m per span), a plurality of embedding materials are arranged in a straight line in the longitudinal direction. Work is required, but the arrangement work is not easy. In addition, due to the buoyancy acting near the abutting portion between the end surfaces of the embedding material, both end regions are lifted and a gap is generated in the abutting portion, where cast-in-place concrete enters, and the planned weight reduction (hollowness) is achieved. It happens that it becomes impossible to obtain.
[0006]
The present invention has been made in view of the above circumstances, and simplifies the work of mounting an embedding material at a construction site, and avoids the generation of a gap in a butt portion between ends of the embedding material. Then, an object of the present invention is to obtain an embedding material for a concrete slab and a concrete slab using the embedding material, which can ensure a predetermined hollow ratio.
[0007]
[Means for Solving the Problems]
An embedding material according to the present invention is an embedding material used for a concrete slab formed by embedding the embedding material in a concrete together with a fixture thereof, wherein two or more unit embedding bodies are continuous in a longitudinal direction. The embedding material main body includes a reinforcing timber that is disposed along at least a top ridge line of the embedding material main body and substantially the entire length in the longitudinal direction. Preferably, the crosspieces for reinforcement are arranged along substantially the entire length in the longitudinal direction also along the bottom ridgeline symmetrical to the top ridgeline.
[0008]
As described above, the embedding material for a concrete slab according to the present invention includes a plurality of unit embedding bodies that are continuous in the longitudinal direction, and crosspieces arranged at least along the top ridge. Since the crosspiece runs in the longitudinal direction, the rigidity (resistance) of the entire embedding material against bending becomes large. In particular, when two crosspieces are arranged along both the top ridge line and the symmetric bottom ridge line, a large bending resistance is exhibited. This improvement in bending resistance basically depends on the physical properties of the crosspiece, and does not depend on the length of each unit embedded body in the longitudinal direction. Therefore, an embedded material having a required bending resistance can be obtained even if a unit embedded body having a short length is used. For example, unit embedded bodies having a length of, for example, about 1 m or shorter formed using a conventional molding die are arranged in the longitudinal direction as many as required in a posture with their end faces facing each other. By attaching the crosspiece along, a desired embedding material can be obtained.
[0009]
The unit embedding body is preferably a foam of a synthetic resin such as expanded polystyrene, but is not limited to this and may be a known hollow embedding material as long as the specific gravity is smaller than the concrete cast in place. In that case, those having a bulk specific gravity of 0.5 or less are preferable. The shape and size of the embedding material may be selected as appropriate according to the design conditions of the concrete slab to be constructed.However, the unit is designed so that the cast-in-place concrete can quickly and sufficiently flow to the back side at the construction site. It is desirable that the cross-sectional shape orthogonal to the longitudinal direction of the embedding body be a shape that gradually widens at least upward from the bottom. It is preferable that the cross-sectional shape orthogonal to the longitudinal direction is circular or elliptical, but a cross-sectional shape such as a combination of a circular or elliptical upper surface and an inverted triangular lower surface may be used. The upper surface side may be a flat surface. However, in this case, it is assumed that the central portion of the flat surface in the widthwise direction corresponds to the “top ridgeline”, and the timber is disposed at that portion.
[0010]
It is desirable that the surface of the embedding material is a smooth flat surface without any irregularities in order to improve the familiarity with the cast-in-place concrete and also to facilitate the casting operation. For this purpose, it is preferable to form a groove having a size and a cross-sectional shape into which the timber enters the unit embedding body, and to embed the timber therein. Preferably, both are bonded and integrated using an adhesive at the time of embedding.
[0011]
Any material can be used for the crosspiece as long as it has a property capable of improving the bending rigidity (resistance) of the embedding material body, which is an aggregate of unit embedding bodies continuous in the longitudinal direction, such as plywood and fiber-reinforced plastic. , Bamboo, wood, thin metal bars, and the like. Plywood is most preferred in terms of cost and workability. The sectional shape is also arbitrary, and may be a solid body or a hollow body.
[0012]
A concrete slab according to the present invention is characterized in that the above-mentioned embedding material is embedded in concrete together with its fixture. At the time of construction, a temporary molding form for concrete casting is erected by a conventionally known method, and a fixing tool is fixed for fixing the embedding material using the temporary molding form. It is desirable that the fixing device is constituted by a lower fixing device for receiving the bottom surface side of the embedding material and a band-shaped member for holding down the upper surface side of the embedding material on which the lower fixing device is mounted.
[0013]
At a required interval, the lower fixture is attached to the temporary mold release mold, and the above-mentioned embedding material is placed thereon. At that time, the timber attached along the top ridge line should be the highest. After that, the embedding material is fixed to the lower fixture using the band-shaped member. In order to prevent the embedding material from rotating unnecessarily, it is desirable to integrate the crosspiece and the band-shaped member with screws or the like. After performing the required fixing work and, if necessary, arranging the necessary reinforcing bars, cast concrete in place. The poured concrete wraps around the embedding material while wrapping around the lower surface side of the embedding material, and gives buoyancy to the embedding material so as to float. However, the embedding material is suppressed by the band-shaped member attached to the fixture, and the entire embedding material does not rise. The buoyancy tries to dig into the embedding material in the band-shaped member, but since the timber runs, the digging is suppressed.
[0014]
Buoyancy also acts on the implant between the fixtures. However, since the embedding material has the crosspiece wood incorporated over the entire length in the longitudinal direction, upward bending is suppressed. For this reason, the cover thickness of the concrete above does not decrease, and there is no contact with the reinforcing bars located above. Since the upward bending is suppressed, no gap is generated at the connection portion between the end faces of the unit embedded body. From those facts, it is possible to maintain the cover thickness and the hollow ratio of the concrete on the upper and lower surfaces after the concrete is poured, as the initial design values. In addition, since the embedding material can suppress the upward bending of the embedding material due to buoyancy due to the presence of the crosspiece, the interval between the fixtures can be set wider, and the work of fixing the embedding material can be simplified.
[0015]
At the actual construction site, workers may walk on the embedded material when fixing the embedded material, when arranging the surrounding reinforcement, and when placing the cast-in-place concrete. It can happen. The unit embedded body has insufficient strength, and the unit embedded body may be deformed by walking. In the embedding material according to the present invention, since the crosspieces are arranged over the entire length of the embedding material main body, the worker pays a little attention, that is, by walking on the crosspieces, Such deformation can be effectively suppressed.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. FIG. 1 is a view for explaining an embedding material according to the present invention. FIG. 1a shows a state before assembling, and FIG. 1b shows a state after assembling. FIG. 2 is a view for explaining a process of constructing a hollow concrete slab using the embedding material shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view showing a state where the embedding material is attached by a fixture. ing. FIG. 4 is an exploded view of the fixture used.
[0017]
In this embodiment, the unit embedding body 1 is a styrofoam molded product having a circular cross section, and has a diameter of about 10 cm to 20 cm and a length of about 80 cm to 110 cm. In the unit embedding body 1, upper concave grooves 2 and lower concave grooves 3 each having a rectangular cross section along the longitudinal direction are formed at diametrically opposed positions. The diameter and length are merely examples, and may be appropriately selected in consideration of the conditions of the hollow concrete slab to be constructed, the foaming mold, and the like.
[0018]
The crosspieces 5 and 6 are long members made of, for example, plywood, and have a cross-sectional shape that can be inserted into the upper concave groove 2 and the lower concave groove 3 formed in the unit embedding body 1. In this example, the upper crosspiece wood 5 and the lower crosspiece wood 6 have the same cross-sectional shape, but they may be different. In that case, the cross-sectional shapes of the upper concave groove 2 and the lower concave groove 3 can be changed accordingly. The length of the crosspieces 5, 6 is at least the length of two unit embedding bodies 1. Preferably, the length is equal to the number of unit embedded bodies 1 continuously arranged in the longitudinal direction at the construction site.
[0019]
The required number of unit embedding bodies 1 are arranged in the longitudinal direction such that the upper concave groove 2 and the lower concave groove 3 are respectively continuous to form an embedding material main body 10. In the illustrated example, the embedding material main body 10 is formed by two unit embedding bodies 1, but this is merely an example, and in actuality, the embedding material main body 10 is configured by a larger number of unit embedding bodies 1. It is usually done. An adhesive such as a vinyl acetate-based acrylic emulsion or an ethylene-vinyl acetate copolymer-based hot melt is applied to the upper concave groove 2 and the lower concave groove 3 of the embedding material main body 10 arranged as described above. An adhesive is also applied to the wood 5 and the lower timber 6 side. In some cases, it is sufficient to apply an adhesive to the upper crosspiece wood 5 and the lower crosspiece wood 6 side.
[0020]
In this state, the upper timber 5 is inserted into the upper groove 2 and the lower timber 3 is inserted into the lower timber 6, and the adhesive is hardened. Thereby, the embedding material 20 according to the present invention is completed. In the illustrated example, the upper surfaces of the upper crosspiece lumber 5 and the lower crosspiece lumber 6 are substantially flush with the surface of the embedding material main body, but are not necessarily flush. Both the upper and lower crosspieces 5 and 6 are inserted into the grooves such that the long sides of the cross sections are horizontal, but are inserted in a state where both or one of them is changed by 90 degrees. You may make it. In this case, greater bending rigidity can be given to the embedding material.
[0021]
When constructing the hollow concrete slab, the temporary mold form 30 is erected by a standard method, and the lower end streaks 31 are arranged thereon. Next, the lower fixing tool 41 of the fixing tool 40 is attached to a predetermined position of the temporary release mold frame 30, the embedding material 20 is placed thereon, and the embedding material 20 is It is fixed to the fixture 41. This is performed for the required number of columns (FIG. 2B) (see also FIGS. 3 and 5).
[0022]
To attach the lower fixing tool 41, the nut member 43 is placed at a predetermined position on the upper surface of the temporary release mold frame 30, and a bolt 44 is inserted and screwed in from the rear surface, so that the nut member 43 is fixed on the upper surface of the temporary temporary mold frame 30. Secure in position. The lower fixture 41 is placed at that position, and the bolt 45 is screwed into the fixed nut member 43 from the bottom surface. Thereby, the lower fixing tool 41 is fixed to the temporary mold release mold 30. Similarly, the required number of lower fixing tools 41 are fixed in an aligned state, and the embedding material 20 is placed on the fixed lower fixing tools 41. At this time, as shown in the figure, the upper crosspiece 5 is placed on top. Next, one hook 46 of the band-shaped member 42 is systematically attached to the stopper 47 of the lower fixture 41, the band-shaped member 42 is laid over the upper surface of the embedding material 20, and the other hook 48 is connected to the lower fixture 41. Is locked to the other stopper piece 49. Then, a nail 50 or a screw is driven into the upper beam 5 from above the band-shaped member 42. Hereinafter, this operation is performed for all the lower fixtures 41. Thereby, the embedding material 20 is fixedly attached to the fixture 40.
[0023]
Thereafter, as shown in FIG. 2c, the upper end bar 32 is arranged as necessary, and the cast-in-place concrete 33 is cast as shown in FIG. 2d. The poured concrete 33 wraps around the embedding material 20 while also wrapping around the lower surface side of the embedding material 20. The concrete slab using the concrete slab embedding material according to the present invention is completed by waiting for the concrete 33 to harden, removing the bolts 44, and removing the temporary mold release mold frame 30.
[0024]
As described above, the cast-in-place concrete 33 causes buoyancy in the embedded material 20. However, the embedding material 20 is suppressed by the band-shaped member 42 attached to the lower fixing tool 41 fixed to the temporary release mold frame 30, so that the entire embedding material 20 does not float. The band-shaped member 42 tries to bite into the unit embedded body 1 by buoyancy, but since the upper timber 5 is running, biting is suppressed.
[0025]
Buoyancy also acts on the embedding material 20 between the fixtures 40, 40, but even if the fixtures 40 are arranged at relatively wide intervals, the timbers 5, 6, which function as reinforcing members attached over the entire length in the longitudinal direction. Works effectively, and upward bending is suppressed. Therefore, the cover thickness of the upper concrete does not decrease, and the concrete does not come into contact with the upper end streaks 32. Since the curving upward is suppressed, there is no gap at the connection between the end faces of the unit embedded body 1. In addition, by causing the worker to walk on the upper crosspiece 5, unnecessary deformation of the unit embedded body 1 can be prevented.
[0026]
【The invention's effect】
As described above, according to the present invention, it is possible to simplify the work of mounting the embedding material at the construction site, and to prevent the embedding material from bending upward due to buoyancy by easy means, A cast-in-place hollow concrete slab having a cover thickness and a hollow ratio as designed can be obtained.
[Brief description of the drawings]
FIG. 1 is a view for explaining an embedding material according to the present invention, wherein FIG. 1a shows a state before assembling and FIG. 1b shows a state after assembling.
FIG. 2 is a diagram illustrating a process of constructing a hollow concrete slab using the embedding material shown in FIG.
FIG. 3 is an enlarged sectional view showing a state in which an embedding material is attached by a fixture.
FIG. 4 is an exploded view showing a fixing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Unit embedding material, 2, 3 ... Groove, 5, 6 ... Wood, 10 ... Embedding material main body, 20 ... Embedding material, 30 ... Demolding temporary formwork, 31 ... Lower end streak, 32 ... Upper end Reinforcement, 33: Cast-in-place concrete 40: Fixing tool, 41: Lower fixing tool, 42: Band member, 50: Nail or screw,

Claims (5)

An embedding material used for a concrete slab formed by embedding an embedding material together with a fixture thereof in concrete, wherein an embedding material main body in which two or more unit embedding bodies are continuous in a longitudinal direction; An embedding material for a concrete slab, comprising reinforcing lumber disposed at least along a top ridgeline of the embedding material body along substantially the entire length in a longitudinal direction thereof. The embedding material for a concrete slab according to claim 1, wherein the crosspiece for reinforcement is arranged along substantially the entire length in the longitudinal direction even along the bottom ridgeline which is symmetrical to the top ridgeline. The embedding material for a concrete slab according to claim 1 or 2, wherein a cross-sectional shape of the unit embedding body orthogonal to the longitudinal direction has a shape that gradually widens at least from a bottom portion upward. The embedding material for a concrete slab according to any one of claims 1 to 3, wherein the unit embedding body is a synthetic resin foam. A concrete slab wherein the concrete slab embedding material according to any one of claims 1 to 4 is embedded in concrete together with the fixture.

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