JP6510323B2 - Precast concrete slab - Google Patents

Description

  The present invention relates to a precast concrete slab which constitutes a part of a half precast synthetic slab, and more particularly to a precast concrete slab in which a void is provided between the rest of the half precast synthetic slab and a cast-in-place concrete layer.

In concrete slabs, it is known to embed a void member in order to reduce the amount of cast concrete and reduce the weight. A void (lack of concrete) is formed by this void member. In general, the void member is made of lightweight foamed polystyrene resin (see Patent Document 1 etc.).
In Patent Document 2, a groove is formed on the upper surface of a precast concrete slab constituting the lower half of a half precast composite slab, the upper end opening of the groove is covered with a partition plate, and a cast-in-place concrete layer is laminated thereon. ing. As a result, the internal space of the recessed groove is a void.

Patent No. 5259465 gazette Japanese Utility Model Application Publication No. 5-30313

Concrete slabs having void members made of expanded polystyrene resin are subject to various constraints for securing fire resistance.
In addition, in the precast concrete slab for half precast synthetic slab of Patent Document 2, it is difficult to notice foreign matter such as water and dust entering the inside of the recessed groove covered with the partition plate, and a cast-in-place concrete layer is cast as it is It is possible to do it.
An object of the present invention is, in view of such circumstances, to secure fire resistance and to prevent the possibility of foreign matter remaining in a void in a precast concrete slab for a half precast synthetic slab having a void.

In order to solve the above problems, the present invention is a precast concrete slab which constitutes a part of a half precast composite slab and in which a void is provided between the rest of the half precast composite slab and a cast-in-place concrete layer. ,
A void recess which is opened to a laminating surface on which the cast-in-place concrete layer is laminated to be the void;
And a reticulated member covering an opening of the void concave portion to the lamination surface.
According to the precast concrete slab for the half precast synthetic slab, when the cast-in-place concrete layer is cast and laminated, it is possible to prevent the concrete from entering the void recess by the mesh member. This makes it possible to secure the void volume. In addition, since the mesh member has a mesh, the mesh member can be made smaller in weight and smaller in volume than the partition plate of Patent Document 2. Therefore, even if the reticulated member is made of a flammable material, the calorific value upon burning can be smaller than that of the partition plate of Patent Document 2, and the fire resistance of the half precast synthetic slab can be sufficiently ensured.
In addition, when the cast-in-place concrete layer is laminated, when foreign matter such as water or dust has entered the void concave portion, it can be easily found and removed. Therefore, the foreign matter can be prevented from remaining in the void.
In addition, the adhesion between the cast-in-place concrete layer and the reticulated member can be enhanced by the fact that the concrete in the cast-in-place concrete layer enters the mesh of the reticulated member. Furthermore, the soundproofness can be improved by making the ceiling surface of the void uneven.

It is preferable that the reticulated member is formed of a metal lath mesh.
As a result, the reticulated member can be made noncombustible, and hence the fire resistance of the half precast composite slab can be reliably ensured. In addition, the material cost can be reduced.

It is preferable that a locking recess for locking an end of the mesh member is formed at a corner between the inner surface of the void recess and the laminated surface.
This allows the mesh member to be stably held by the precast concrete slab.

It is preferable that the mesh member is curved to be convex upward.
This allows the mesh member to be held firmly to the precast concrete slab by elastic force. In addition, it is possible to suppress or prevent the mesh member from being dented by the weight of the cast-in-place concrete, and the void volume can be secured.

  According to the present invention, fire resistance can be secured by using a net-like member as the void forming member. Further, when foreign matter such as water or dust enters the void concave portion, it can be easily found and removed, and the foreign matter can be prevented from remaining in the void. Furthermore, soundproofness can be improved.

FIG. 1 shows a half-precast composite slab according to a first embodiment of the present invention, in which a precast concrete slab constituting a part is shown by a solid line, and a remaining cast-in-place concrete layer is shown by a two-dot chain line. It is front sectional drawing in alignment with an II line of. FIG. 2 is a plan view of the precast concrete slab. FIG. 3 is a cross-sectional view showing a part of the half precast composite slab in an enlarged manner. FIG. 4 is a front sectional view showing a half-precast composite slab according to a second embodiment of the present invention, in which a precast concrete slab constituting a part thereof is indicated by a solid line, and a remaining cast-in-place concrete layer is indicated by a two-dot chain line. It is. FIG. 5 is a front sectional view showing a half precast composite slab according to a third embodiment of the present invention, showing a precast concrete slab constituting a part by a solid line, and showing a remaining cast-in-place concrete layer by a two-dot chain line. It is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a half precast composite slab 1 according to a first embodiment of the present invention. The half precast synthetic slab 1 is provided with a precast concrete slab 10 and a cast-in-place concrete layer 20 indicated by a two-dot chain line in FIG. The cast-in-place concrete layer 20 is stacked on the upper side of the precast concrete slab 10. Between the precast concrete slab 10 and the cast-in-place concrete layer 20 in the inside of the half precast synthetic slab 1, a void 1a (a cavity or a concrete defect portion) is formed.

  As shown in FIG. 1 and FIG. 2, the precast concrete slab 10 has a reinforced concrete structure including concrete 11 and reinforcing bars 12 arranged therein. The precast concrete slab 10 has a bottom plate portion 13 and a plurality of ridges 14. The bottom plate portion 13 has a flat plate shape extending in the front, rear, left and right. A plurality of ridges 14 are provided on the upper surface of the bottom plate 13 so as to project upward. Each of the ridges 14 has, for example, a substantially rectangular cross section, and extends in the front-rear direction (the direction orthogonal to the paper surface of FIG. 1, the vertical direction of FIG. 2). A plurality of ridges 14 are arranged at intervals on the left and right.

  A void recess 15 is formed between adjacent ridges 14. The void recess 15 is opened to reach the upper surface of the ridge portion 14 and thus the upper surface 10a (laminated surface) of the precast concrete slab 10, and has a groove shape extending in the front-rear direction. The internal space of the void recess 15 is a void 1a.

  As shown in FIGS. 1 and 2, the precast concrete slab 10 further includes a reticulated member 30. The mesh member 30 extends in the same direction as the void recess 15. The mesh member 30 entirely covers the upper end opening of the void recess 15 by straddling between the upper ends of the adjacent ridges 14 and 14. The net-like member 30 is constituted by a ras mesh. The material of the lath mesh is, for example, a metal such as steel, iron, stainless steel or the like. Preferably, the net-like member 30 is constituted by a punching metal made of lath mesh. The size of the mesh 31 of the net-like member 30 is preferably such that coarse aggregates (not shown) such as gravel and crushed stone in the cast-in-place concrete layer 20 can not pass through. The diameter is about 3 mm to 15 mm. The thickness of each wire 32 of the mesh member 30 is about 0.1 mm to 3 mm.

  A locking recess 16 is formed at a corner between the side surface 14 b (the inner side surface of the void recess 15) of the ridge portion 14 and the upper surface 10 a. The end 30 e in the width direction of the mesh member 30 is locked in the locking recess 16. The width dimension when the mesh member 30 is flat is larger than the width of the void recess 15. Therefore, the mesh member 30 is curved along the width direction so as to be convex upward.

  As shown in FIG. 3, a cast-in-place concrete layer 20 is laminated on the precast concrete slab 10 and thus on the reticulated member 30. A portion 21 a of the concrete 21 of the cast-in-place concrete layer 20 enters the mesh 31 and further wraps the wire 32. The ceiling surface 1 b of the void 1 a is defined by the part of the concrete 21 a and the reticulated member 30. The ceiling surface 1b of the void 1a is uneven.

The above-mentioned half precast synthetic slab 1 is produced as follows.
In a precast concrete manufacturing plant, a form for a precast concrete slab 10 is constructed. Rebars 12 are arranged in the formwork. It is not necessary to attach the mesh member 30 to the formwork.
Next, concrete 11 is placed in the formwork.
After curing until the concrete 11 hardens, the formwork is removed.

The mesh member 30 is attached to the void recess 15 of the concrete 11. At this time, the mesh member 30 is curved so as to be upwardly convex, and both end portions 30 e in the width direction of the mesh member 30 are locked in the locking recesses 16, 16. The bent mesh member 30 tries to return to a flat state by elasticity, so that both end portions 30e, 30e strongly hit the inner surfaces or corners of the locking recesses 16, 16 and are caught. Thereby, the mesh member 30 can be stably installed on the precast concrete slab 10.
As compared with the case of installing a large void member that fills the entire void, such as expanded polystyrene, the labor and effort of the installation operation can be simplified.

The precast concrete slab 10 produced as described above is transported to a construction site of a building for installation.
A formwork for the cast-in-place concrete layer 20 is assembled around the precast concrete slab 10, and reinforcing bars 22 are arranged above the precast concrete slab 10 to cast concrete 21. Thus, the cast-in-place concrete layer 20 is stacked on the precast concrete slab 10.

When the concrete 21 is cast, the net-like member 30 can prevent the concrete 21 from being filled inside the void recess 15. Thus, the internal space of the void recess 15 can be left as a cavity, and the volume of the void 1a can be secured.
A portion 21 a of the concrete 21 enters the mesh 31. By this, the mesh member 30 can be integrated with the concrete 21.
Coarse aggregates such as crushed stone in the concrete 21 are prevented from passing through the mesh 31. Although fine aggregate such as sand may pass through the mesh 31, such fine aggregate is sufficiently retained in the concrete 21a, so that it can be prevented from falling to the bottom of the void 1a.

According to the precast concrete slab 10, since the void forming member is the reticulated member 30, the weight can be reduced as compared with the case where the void member made of general foamed polystyrene is used, and furthermore, the mesh 31 is formed. The weight can be reduced more reliably than in the case of using the partition plate of Document 2.
Further, by forming the reticulated member 30 with a metal lath mesh, not only the fire resistance can be sufficiently secured, but also the material cost can be reduced.
Furthermore, when the cast-in-place concrete layer 20 is laminated at the construction site, if foreign matter such as water or dust has entered into the void recess 15, the foreign matter can be easily found visually through the mesh 31. Therefore, the concrete 21 can be cast after removing foreign matter. This can prevent foreign matter from remaining in the half precast composite slab 1.
Moreover, since the reticulated member 30 is curved so as to be convex upward, it is possible to develop the strength against the load at the time of placing the concrete 21. Thereby, the volume of the void 1a can be secured.
Furthermore, since the ceiling surface of the void 1a is formed by the net-like member 30 and the concrete 21a which has entered the mesh 31 thereof and is uneven, when the sound passes through the half precast composite slab 1, it strikes the uneven ceiling surface. It is scattered. Thereby, the soundproofness of the half precast synthetic slab 1 can be improved.

Next, another embodiment of the present invention will be described. The same numerals are given to a drawing about a configuration which overlaps with a form as stated above in the following embodiments, and explanation is omitted.
FIG. 2 shows a second embodiment of the present invention. The mesh member 30 </ b> B of the second embodiment includes a main portion 35 and a pair of legs 36. The main part 35 is flat. Both ends in the width direction of the main portion 35 are bent downward substantially at right angles to form the leg portion 36. The leg 36 is locked in the locking recess 16.

  FIG. 3 shows a third embodiment of the present invention. The mesh member 30C of the third embodiment is entirely flat. Both ends of the mesh member 30 </ b> C are accommodated in the locking recess 16 and fixed to the concrete 11 by the concrete nail 34.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.
For example, the mesh member is not limited to metal but may be resin or the like. Since the mesh-like member is light in mass and small in volume, the amount of heat generated when it burns can be made smaller than the void member made of expanded polystyrene or the partition plate of Patent Document 2 even if it is flammable, and the fire resistance is excellent. ing.
The reticulated members 30, 30B of the first and second embodiments may also be fixed to the concrete 11 by the concrete nails 34 of the third embodiment.

  The present invention is applicable to, for example, the construction of a reinforced concrete structure.

1 half precast synthetic slab 1a void 10 precast concrete slab 10a top surface (laminated surface)
14b Side surface (inner side surface of void recess)
15 Void recess 16 Locking recess 20 cast-in-place concrete layer 30, 30B, 30C Reticulated member 30e end

Claims (2)

A precast concrete slab which constitutes a part of a half precast composite slab and in which a void is provided between the rest of the half precast composite slab and a cast-in-place concrete layer,
A groove-shaped void-forming recess that is to be the void that is opened to the laminating surface on which the cast-in-place concrete layer is to be laminated;
And a net-like member extending in the same direction as the void recess and covering the opening of the void recess to the stacking surface, the inner surface and the stacking surface on both sides in the width direction orthogonal to the extending direction of the void recess. A locking recess is formed at the corner of the frame, and the width dimension when making the mesh member flat is larger than the width dimension of the void recess, and the mesh member is convex in the width direction. By bending along the length and trying to return to a flat state by elasticity, both ends in the width direction of the mesh member are elastically pressed against the inner surface of the locking recess or the corner of the locking recess precast concrete slab, characterized in that is. The precast concrete slab according to claim 1, wherein the reticulated member is formed of a metal lath mesh.

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