JP7029950B2 - Construction method of sound absorbing concrete and surface member for fixing - Google Patents

Description

The present invention relates to a method for constructing sound-absorbing concrete and a surface-shaped member for fixing.

Depending on the purpose of the classroom, church, music hall, etc., the walls and ceiling may have a sound absorbing effect. When the wall is finished with exposed concrete, a Helmholtz-type sound absorbing mechanism may be provided inside the wall because a sound absorbing plate for preventing the generation of reflected sound cannot be installed on the surface. In order to provide the Helmholtz-type sound absorbing mechanism in the wall, there are a method of burying a Helmholtz resonator in the wall and a method of forming the sound absorbing mechanism by a construction method as in Patent Document 1.

When burying the Helmholtz resonator in the wall, the opening of the Helmholtz resonator is closed with adhesive tape, and concrete is poured with the Helmholtz resonator fixed to a reinforcing bar or a formwork.

In Patent Document 1, concrete is cast in a state where a box-shaped discard mold is installed to form a cavity, and in a subsequent process, a through hole is formed from the surface of the hardened concrete to the cavity to form a Helmholtz. A method of forming a mold sound absorbing mechanism is disclosed.

Japanese Unexamined Patent Publication No. 2014-844578

In the conventional construction method, when the concrete is placed, the position of the Helmholtz resonator may be displaced or the adhesive tape may be peeled off to close the opening due to the pressure of the concrete or the vibration of the vibrator. Further, when the Helmholtz resonator is attached to the reinforcing bar, the distance between the cavity and the formwork becomes long, and the neck-shaped opening becomes long, so that the Helmholtz resonator is easily damaged when the concrete is placed. Further, in the construction method of Patent Document 1, there is a problem that the position of the box-shaped discard mold is displaced at the time of placing concrete, and there is also a problem that the construction time is increased because a through hole is formed in a subsequent process. ..

From this point of view, the present invention is a method for constructing sound-absorbing concrete that can form a Helmholtz-type sound-absorbing mechanism at an accurate position and does not require the work of drilling a through hole, and a fixing preferably used for the construction method. An object of the present invention is to provide a surface-like member.

The first invention for solving such a problem is a method of constructing sound-absorbing concrete in which a Helmholtz resonator having a cavity and an opening is embedded in the surface, and a plurality of protrusions arranged in parallel at a predetermined pitch are formed. The helmholtz resonator is fixed by a preparatory step of preparing the provided surface-shaped member for fixing, an installation step of installing the surface-shaped member for fixing inside the mold, and inserting the protrusion into the opening. The fixing process of fixing to the surface-shaped member, the placing process of placing concrete in the mold, the dismantling process of disassembling the mold, and the removal process of removing the surface-shaped member for fixing are performed. The preparatory step is a method for constructing sound-absorbing concrete, characterized in that the arrangement pitch of the protrusions is determined according to the required sound-absorbing performance .

According to such a construction method, since the Helmholtz resonator can be fixed by inserting the Helmholtz resonator into the protrusion through the opening, it is possible to prevent the Helmholtz resonator from being displaced when the concrete is placed. Therefore, the Helmholtz resonator can be formed in the correct position. Further, since the Helmholtz resonator is fixed to the fixing surface member installed on the formwork, the length of the opening does not become larger than necessary. Therefore, it is possible to prevent the opening from being easily damaged. Further, after the concrete is hardened, the opening is opened by removing the fixing surface member, so that it is not necessary to perform the work of drilling a through hole.

A second invention for solving the above-mentioned problems is a fixing surface used for fixing the Helmholtz resonator when constructing a sound-absorbing concrete in which a Helmholtz resonator having a cavity and an opening is embedded in a surface. It is a shaped member and includes a formwork installation surface that abuts on the inner surface of the formwork and a surface that faces the concrete casting portion, and the opening on the surface facing the casting portion. It is a fixing surface-shaped member characterized in that a plurality of protrusions inserted through the portions are arranged in parallel at a predetermined pitch .

With such a configuration, the Helmholtz resonator can be easily fixed. Further, since the opening of the Helmholtz resonator appears on the concrete surface only by removing the fixing surface member, it is not necessary to make a through hole after the concrete is hardened. Moreover, since the position of the Helmholtz resonator does not shift when the concrete is placed, the Helmholtz resonator can be formed at an accurate position.

Further, in the fixing planar member of the present invention, it is preferable that the cross-sectional shape of the protrusion is equivalent to the cross-sectional shape of the opening. According to such a configuration, since the protrusion is fitted to the tubular member constituting the opening, it becomes more difficult for concrete to flow into the opening.

According to the present invention, a Helmholtz-type sound absorbing mechanism can be formed at an accurate position, and sound absorbing concrete can be constructed without drilling through holes.

It is a perspective view which showed the fixing surface member and Helmholtz resonator which concerns on embodiment of this invention. It is sectional drawing which showed the fixing process of the construction method of the sound absorbing concrete which concerns on embodiment of this invention. It is sectional drawing which showed the casting process of the construction method of the sound absorbing concrete which concerns on embodiment of this invention. It is sectional drawing which showed the dismantling process and the removal process of the construction method of the sound absorbing concrete which concerns on embodiment of this invention. It is a perspective view which showed an example of the Helmholtz resonator. (A) is a cross-sectional view showing a Helmholtz resonator according to the present embodiment, and (b) to (e) are cross-sectional views showing a modified example of the Helmholtz resonator.

Hereinafter, the method of constructing the sound-absorbing concrete and the surface-shaped member for fixing according to the embodiment of the present invention will be described with reference to the attached drawings. The sound-absorbing concrete constructed in the present embodiment is constructed with an exposed concrete finish, and is used for the walls and ceilings of living rooms such as prayer rooms and music halls of classrooms and churches where reflected sound is an obstacle. .. As shown in FIG. 4, the Helmholtz resonator 10 is embedded in the sound absorbing concrete 1. The Helmholtz resonator 10 is open to the indoor surface of the sound absorbing concrete 1. The fixing surface member 2 is for fixing the Helmholtz resonator 10 when constructing the sound absorbing concrete 1.

As shown in FIGS. 1 and 2, the Helmholtz resonator 10 is configured to include a cavity 11 and an opening 12. The hollow portion 11 is partitioned by a hollow container 13 having a circular bottom surface portion 13a, a cylindrical side surface portion 13b, and a circular top surface portion 13c, and has a cylindrical shape (circular cross section). A hole connected to the opening 12 is formed in the center of the top surface portion 13c. The dimensions and shape of the cavity 11 are appropriately determined according to the frequency band of the sound to be reduced. The depth dimension of the cavity 11 (the depth dimension along the direction orthogonal to the surface of the sound absorbing concrete 1) is shorter than the wavelength of the sound to be reduced. The arrangement pitch of the Helmholtz resonator 10 is determined according to the required sound absorption performance within a range in which the strength of the sound absorbing concrete 1 can be secured. The cross-sectional shape of the cavity 11 is not limited to a circle, and may be another shape such as an ellipse, a rectangle, or a polygon.

The opening 12 is formed in a neck shape extending from the cavity 11 by a predetermined length. The opening 12 is partitioned by a cylindrical member 14 and is formed to have a circular cross section. One end of the cylindrical member 14 is fixed to the central portion of the top surface portion 13c of the hollow container 13. The opening 12 has a diameter smaller than the diameter of the cavity 11. The dimensions and shape of the opening 12 are appropriately determined according to the frequency band of the sound to be reduced. The opening 12 is not limited to a circular cross section, and may have another shape such as a polygonal cross section or an elliptical cross section.

The Helmholtz resonator 10 is made of a material such as resin or metal, and is formed to have a thickness that is not deformed by the pressure of concrete. Further, if the Helmholtz resonator 10 is formed by solidifying a material that can be expected to react with cement hydrate, such as blast furnace slag fine powder and fly ash, the adhesion between concrete and the Helmholtz resonator 10 is further enhanced. Can be enhanced.

Below, as a modification of the configuration in which the Helmholtz resonator can be easily formed, it is formed of a vinyl chloride resin pipe (hereinafter referred to as "PVC pipe") and a vinyl chloride resin plate material (hereinafter referred to as "PVC panel"). Explain what you did. As shown in FIG. 5, in the Helmholtz resonator 10A, the hollow container 13 is composed of a PVC pipe and a PVC panel, and the cylindrical member 14 is composed of a PVC pipe.

The side surface portion 13b of the hollow container 13 is composed of a PVC pipe, and the bottom surface portion 13a and the top surface portion 13c of the hollow container 13 are composed of a PVC panel. The PVC pipe constituting the side surface portion 13b has a cylindrical shape having a large inner diameter and a relatively short axial length. The internal space of the PVC pipe constituting the side surface portion 13b has a volume required for the required sound absorption performance. The vinyl chloride panel constituting the bottom surface portion 13a and the top surface portion 13c is a plate material covering the openings at both ends of the side surface portion 13b, and has a square shape having a side length slightly longer than the outer diameter of the side surface portion 13b. The PVC pipe constituting the cylindrical member 14 has a cross-sectional area and a length required for the required sound absorption performance.

According to the Helmholtz resonator 10A having such a configuration, it can be formed for use only by appropriately cutting and adhering the PVC pipe and the PVC panel. Further, since the peripheral portions of the bottom surface portion 13a and the top surface portion 13c project outward from the side surface portions 13b, the adhesion to the concrete can be enhanced. The shape of the vinyl chloride panel is not limited to a square, but may be circular.

The Helmholtz resonator 10 can have variations as shown in FIG. 6 (a) shows the Helmholtz resonator 10 shown in FIG. 2, and (b) to (e) show the Helmholtz resonators 10B to 10E according to the modified example. In FIGS. 6 (b) to 6 (e), the parts different from the Helmholtz resonator 10 in (a) will be mainly described, and the equivalent parts will be designated by the same reference numerals and the description thereof will be omitted.

In the Helmholtz resonator 10B of FIG. 6B, the axial length of the side surface portion 13bB of the hollow container 13B is large. As a result, the depth dimension of the cavity portion 11B is increased, and the volume of the cavity portion 11B is also increased. According to such a Helmholtz resonator 10B, the resonance frequency becomes low.

In the Helmholtz resonator 10C of FIG. 6C, the diameters of the bottom surface portion 13aC and the top surface portion 13cC of the hollow container 13C are small. As a result, the cross-sectional area of the cavity 11C is reduced, and the volume of the cavity 11C is also reduced. According to such a Helmholtz resonator 10C, the resonance frequency becomes high.

In the Helmholtz resonator 10D of FIG. 6D, the shape of the hollow container 13 does not change, the diameter of the cylindrical member 14D does not change, and the axial length increases. The protrusion 6 is inserted through the elongated opening 12D. According to such a Helmholtz resonator 10D, the resonance frequency is lowered.

In the Helmholtz resonator 10E of FIG. 6 (e), the shape of the hollow container 13 does not change, and a sound absorbing material 17 such as glass wool is provided in the hollow portion 11 inside the hollow container 13. According to such a Helmholtz resonator 10E, the frequency range for absorbing sound is widened. As described above, if the Helmholtz resonators 10B to 10E having various shapes are formed, sound absorption in a wide frequency band becomes possible.

As shown in FIGS. 2 and 3, the fixing surface member 2 is for fixing the Helmholtz resonator 10 in the concrete casting area inside the formwork 3. The fixing surface-shaped member 2 is made of a resin sheet-shaped member, and can be deformed according to the shape of the mold 3. The fixing surface member 2 includes a formwork installation surface 4 and a casting portion facing surface 5. A protrusion 6 is formed on the surface facing the casting portion 5.

The formwork installation surface 4 is a surface that abuts on the inner surface (concrete casting portion side) of the formwork 3, and is composed of one surface of the fixing surface member 2. The formwork installation surface 4 is configured to be flat, and is coated with an adhesive in order to have adhesiveness. The adhesive does not peel off the fixing surface member 2 from the formwork 3 when concrete is placed in a state where the Helmholtz resonator 10 is fixed to the fixing surface member 2, and the formwork 3 is fixed when the formwork 3 is removed. A member having an adhesiveness that can be peeled off from the formwork member 2 is used.

The casting portion facing surface 5 is a surface facing the concrete casting portion, and is composed of the other surface of the fixing surface-shaped member 2 (the back surface of the formwork installation surface 4). The surface facing the casting portion 5 is a surface on which the placed concrete comes into contact.

The protrusion 6 is a portion inserted into the opening 12 of the Helmholtz resonator 10, and serves to fix the Helmholtz resonator 10 to the fixing surface member 2. The cross-sectional shape of the protrusion 6 is equivalent to the cross-sectional shape of the opening 12, and has a cylindrical shape. The protrusion 6 is fitted into the opening 12. The protruding length of the protrusion 6 is slightly shorter than the axial length of the cylindrical member 14. The protruding length of the protrusion 6 may be longer than the axial length of the cylindrical member 14 as long as the tip portion of the protrusion 6 does not abut on the bottom surface portion 13a of the hollow container 13. A plurality of protrusions 6 are arranged in parallel at a predetermined pitch in the horizontal direction, and a plurality of protrusions 6 are arranged in parallel at a predetermined pitch in the vertical direction. That is, the protrusions 6 are arranged linearly in the horizontal direction and the vertical direction, respectively. The protrusions 6 may be offset in each row to shift the installation position so as to be arranged in a staggered manner.

Next, a construction method for constructing the sound-absorbing concrete in which the Helmholtz resonator 10 is embedded in the surface by using the fixing surface-shaped member 2 will be described. The sound-absorbing concrete construction method includes a preparation process, an installation process, a fixing process, a formwork installation process, a casting process, a dismantling process, and a removal process.

The preparation step is a step of preparing the fixing planar member 2. In the preparatory step, for example, the protrusion 6 is adhered or welded to a flat plate-shaped resin sheet to form the fixing surface-shaped member 2. The resin may be poured into a mold to form the fixing planar member 2.

As shown in FIG. 2, the installation step is a step of installing the fixing surface-shaped member 2 inside the formwork 3. In the installation process, an adhesive is applied to the formwork installation surface 4, and the fixing surface-like member 2 having adhesiveness is attached to the formwork 3. As the adhesive, an adhesive that can peel off the fixing surface member 2 and the mold 3 in a later process is used. As a result, the fixing surface member 2 is temporarily fixed to the formwork 3. The fixing surface-shaped member 2 may be attached to the entire inner surface of the formwork 3, or a standardized small-area fixing surface-shaped member may be attached in combination with a necessary portion. The adhesive may be applied to the inner surface of the mold 3 instead of the fixing surface member 2.

As shown in FIGS. 1 and 2, the fixing step is a step of fixing the opening 12 of the Helmholtz resonator 10 to the protrusion 6 of the fixing surface member 2. Specifically, the protrusion 6 is covered with the cylindrical member 14, and the protrusion 6 is inserted into the opening 12. As a result, the protrusion 6 is fitted to the cylindrical member 14, and the Helmholtz resonator 10 is fixed to the fixing surface member 2. At this time, the tip surface of the cylindrical member 14 is brought into contact with the casting portion facing surface 5.

The formwork installation process is a process of installing the formwork 3. In the formwork installation process, the formwork 3 is installed so as to surround the reinforcing bars 21 arranged. The formwork 3 is installed in a state where the fixing surface member 2 and the Helmholtz resonator 10 are fixed.

The placing step is a step of placing concrete 20 in the formwork 3. In the placing step, concrete 20 having high fluidity is placed so that the concrete 20 is filled tightly to the periphery of the Helmholtz resonator 10. In the placing step, it is preferable to place the concrete 20 at a position away from the Helmholtz resonator 10 so that the concrete 20 does not fall directly onto the Helmholtz resonator 10. Further, it is preferable to insert the vibrator (not shown) that vibrates the concrete 20 at a position where it does not collide with the Helmholtz resonator 10. Since the Helmholtz resonator 10 is firmly fixed by being fitted to the protrusion 6, the position does not shift even if the cast concrete 20 collides with the concrete 20 to some extent.

As shown in FIG. 4, the dismantling step is a step of dismantling (demolding) the mold 3. The dismantling step is performed after the concrete has developed a predetermined strength. In the dismantling step, the formwork 3 is dismantled while leaving the fixing planar member 2. In this way, by allowing the fixing surface member 2 to remain for a while even after the mold is removed, it is possible to prevent the surface of the concrete 20 from drying.

The removal step is a step of removing the fixing surface member 2 from the hardened concrete 20. In the removing step, the fixing surface member 2 is pulled and the protrusion 6 is pulled out from the opening 12. Since the tip surface of the cylindrical member 14 that partitions the opening 12 was in contact with the casting portion facing surface 5, when the fixing surface member 2 was removed, the tip surface of the cylindrical member 14 and the surface of the concrete 20 became surfaces. The opening 12 of the Helmholtz resonator 10 exposes the concrete to the surface of zero.

According to the above-mentioned construction method of sound-absorbing concrete, the Helmholtz resonator 10 can be easily and firmly fixed by fitting the opening 12 of the Helmholtz resonator 10 into the protrusion 6 of the fixing surface member 2. This makes it possible to prevent the Helmholtz resonator 10 from being displaced when the concrete 20 is placed. Therefore, the Helmholtz resonator 10 can be formed at an accurate position.

Further, since the Helmholtz resonator 10 can be fixed only by fitting the protrusion 6 to the cylindrical member 14, the fixing work becomes much easier and the fixing position is much easier than in the conventional case where the protrusion 6 is fixed to the reinforcing bar or the like with a wire. Becomes accurate.

After the concrete 20 is hardened, the opening 12 is exposed only by removing the fixing surface member 2, so that it is not necessary to make a through hole as in the conventional case. Therefore, the Helmholtz resonator 10 embedded in the concrete 20 can be easily formed.

Further, since the protrusion 6 is inserted through the opening 12, the opening 12 is cured. Therefore, the concrete 20 does not flow into the opening 12. Further, since the tip surface of the cylindrical member 14 is in contact with the casting portion facing surface 5, the concrete 20 does not enter between the tip surface of the cylindrical member 14 and the casting portion facing surface 5. Therefore, it is possible to reliably prevent the opening 12 from being blocked by the concrete 20.

Further, since the Helmholtz resonator 10 is fixed to the fixing surface member 2 in contact with the surface of the concrete 20, the cylindrical member 14 constituting the opening 12 is compared with the case where the Helmholtz resonator 10 is attached to a reinforcing bar away from the surface of the concrete. Can be shortened. As a result, it is possible to prevent the Helmholtz resonator 10 from being easily damaged, and it is possible to secure the length of the opening 12 according to the required sound absorption effect.

In the present embodiment, since the fixing surface member 2 is made of resin, the fixing surface is used for various shapes of the form 3 and the separator cone and insert installed on the inner surface of the form. The shape of the shape member 2 can be flexibly followed and matched.

Further, since the fixing surface member 2 and the formwork 3 can be used repeatedly, the construction cost can be reduced. In particular, in the formwork 3, the concrete does not come into direct contact with the fixing surface member 2 due to the laying. As a result, the surface of the mold 3 is protected and the number of diversions can be increased. Further, it is not necessary to specially manufacture a dedicated formwork, and the existing formwork can be used as it is.

Although the embodiment for carrying out the present invention has been described above, the present invention is not limited to the above-described embodiment, and the design can be appropriately changed without departing from the spirit of the present invention. For example, in the above-described embodiment, the fixing surface-shaped member 10 is formed in the form of a sheet that can be deformed with a resin, but the present invention is not limited to this. When the shape of the formwork 3 is all flat, the fixing surface-shaped member may be formed of a metal or the like into a plate shape that cannot be deformed.

Further, in the above embodiment, an adhesive is applied to the formwork installation surface 4 in order to fix the fixing surface member 2 to the formwork 3, but the present invention is not limited to this. For example, the fixing surface-shaped member 2 may be fixed to the mold 3 by using an adhesive tape, screws, or the like. For fixing the fixing surface member 2 to the formwork 3, the optimum one may be appropriately selected according to the material, dimensions and shape of the formwork 3 and the fixing surface member 2.

Further, in the above-described embodiment, the sound-absorbing concrete constructed by the exposed concrete finish has been described as an example, but the present invention is not limited to this. For example, the present invention can be applied even when a finish coating is applied to the surface of sound-absorbing concrete or a finishing material having through holes formed at a position corresponding to the opening 12 is laid. When laying the finishing material, the diameter of the through hole should be the same as that of the opening, and the total length of the through hole and the length of the opening should be the same as the length according to the required sound absorption effect. Is preferable.

1 Sound-absorbing concrete 2 Fixing surface member 3 Formwork 4 Formwork installation surface 5 Casting part facing surface 6 Protrusion 10 Helmholtz resonator 11 Hollow part 12 Opening 13 Hollow container 14 Cylindrical member 20 Concrete

Claims (3)

It is a method of constructing sound-absorbing concrete in which a Helmholtz resonator with a cavity and an opening is embedded in the surface.
A preparatory step for preparing a fixing planar member having a plurality of protrusions arranged in parallel at a predetermined pitch, and
The installation process of installing the fixing surface member inside the formwork,
A fixing step of fixing the Helmholtz resonator to the fixing surface member by inserting the protrusion into the opening, and a fixing step.
The casting process of placing concrete in the formwork and
The dismantling process of dismantling the formwork and
A removal step for removing the fixing surface member is provided.
In the preparation step, the arrangement pitch of the protrusions is determined according to the required sound absorption performance.
A method of constructing sound-absorbing concrete, which is characterized by this. A fixing surface member used for fixing the Helmholtz resonator when constructing a sound-absorbing concrete in which a Helmholtz resonator having a cavity and an opening is embedded in the surface.
It is provided with a formwork installation surface that abuts on the inner surface of the formwork and a surface that faces the concrete placement part.
A surface-shaped member for fixing, characterized in that a plurality of protrusions inserted through the opening are arranged in parallel on the facing surface of the casting portion at a predetermined pitch . The surface-shaped member for fixing according to claim 2, wherein the cross-sectional shape of the protrusion is equivalent to the cross-sectional shape of the opening.

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