JPH11131624A - Sound absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability by integrally connecting a large number of aggregate comprising gravel, with a bond formed of cement to form a plate body or a block body with permeability, and embedding a reinforcing member in the plate body or block body. SOLUTION: A reinforcement 4 serving as reinforcing material is built into a form, and a large number of aggregate comprising weighty gravel 2 of 5-30 mm in grain diameter, Portland cement and water are poured thereon and hardened to form a gas-water permeable plate body 1 of 20-50% in the percentage of void with a large number of continuous open pores between the respective gravel 2. The gravel 2 are exposed to the surface of the plate body 1 to form uneven face shape. This plate body 1 of rectangular shape is built up along the inside wall of a tunnel and used to absorb low frequency noise in the tunnel. A sound absorber with strength enough to stand use even under an adverse condition such as the outdoors can therefore be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sound absorber used mainly outdoors.

[0002]

2. Description of the Related Art In recent years, noises generated by running trains and automobiles along railways and roads have become a problem, and it is necessary to reduce noises.

[0003]

By the way, as the sound absorbing material, for example, those made of glass wool or asbestos, and those made of foamed concrete are found, but none of these sound absorbing materials has strength and weight. Unsuitable for use in places where it joins. In particular, especially for glass wool and asbestos, it has a bad effect on the human body,
It is difficult to use outdoors because it is susceptible to rainwater, and foamed concrete has a problem that the surface is easily scratched and easily damaged by impact, such as outdoors in poor conditions Can not withstand use in

[0004] The present invention has been developed in view of the above-mentioned circumstances, and it is intended to endure its use not only indoors but also under bad conditions such as outdoors and at a low cost. The aim is to provide a sound absorber that can be manufactured.

[0005]

In order to achieve the above object, the invention according to claim 1 has a particle size of 5 mm to 30 mm.
A large number of aggregates having a high weight were joined together by a bonding agent to form a plate or block having air permeability of 20% to 50%. The invention according to claim 2 uses stone as an aggregate according to claim 1 and cement as a bonding agent.

According to the third aspect of the present invention, a reinforcing member 4 such as a reinforcing bar is buried in the plate 1 or the block 10 so that the strength of the plate 1 or the block 10 is further increased. It is. The invention according to claim 4 has the water permeability in the invention according to claim 1, 2 or 3.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The sound absorber shown in the figure is assembled along the inner wall of a tunnel T as schematically shown in FIG.
The sound absorber is mainly used for absorbing low-frequency noise in the tunnel T. This sound absorber is a plate having a rectangular shape in a plan view formed by integrally combining a large number of heavy aggregates with a bonding agent. Formed on body 1.

In the above embodiment, the plate 1 is formed so as to have air permeability and a porosity of about 30%, and to expose the aggregate on the surface of the plate 1. The surface is formed as an uneven surface. That is, the sound absorber of the present invention shown in the figure basically has an average particle size of 10 mm as an aggregate.
A gravel 2 having a moderate weight is used, and Portland cement 3 is used as a bonding agent. Specifically, a reinforcing bar 4 as a reinforcing material is incorporated in a predetermined formwork. A mixture obtained by mixing the gravel 2, Portland cement 3, and water having the above-described particle size and kneading the mixture was poured into the mold and hardened to form a continuous open pore 20 between the gravel 2. % Of the sheet 1 having air permeability and water permeability.

At the time of forming the above-mentioned plate 1, it is desirable to compress a mixture of gravel 2, Portland cement 3, and water as an aggregate filled in the mold with the mold, and compress the mixture with the mold. Thereby, the bonding force between the gravel 2 via the Portland cement 3 is increased, and the plate 1 having high strength is obtained. In the above embodiment, the outer periphery of the plate 1 is
A frame-shaped reinforcing wall portion 11 is provided around the plate body 1 so as to surround the plate body 1 integrally with ordinary concrete containing a mixture of gravel, sand, and water having a small particle size, thereby increasing the strength of the plate body 1. I try to raise it even further.

The plate 1 having the above structure is formed by bonding the gravel 2 with the Portland cement 3, so that it can be used outdoors. In the embodiment shown in FIG. 5, the plate 1 is used by being attached along the inner wall of the tunnel T. Thus, in the above-mentioned plate body 1, as described above, it has air permeability with a porosity of about 30%, and has a large number of continuous open pores 20.
However, the noise of the train running in the tunnel T enters the many continuous open holes 20 opening on the side surface of the plate 1 because the train extends in the plate 1 vertically and horizontally like a maze. As shown by the arrow in FIG. 5, while entering the inside of the plate 1 in the direction along the side surface of the plate 1, the light is efficiently absorbed in the plate 1 and noise can be reduced.

As a result of the experiment, according to the plate body 1 of the above embodiment, it is possible to efficiently absorb low-frequency noise of about 250 Hz (for example, in the reverberation room absorption rate of 250 H
It can be expected that noise at frequencies in the z region is reduced to about 0.5 to 0.7. ), It was found to be effective in absorbing mainly low-frequency noise in the tunnel T.

Accordingly, in a Shinkansen or the like employing a so-called slab track in which rails are directly laid on a concret, the plate 1 is laid on a line in the tunnel T, or a cover for a gutter in the tunnel T as described later. It is also possible to reduce the noise of the train efficiently by using it, and it is very effective in reducing the ultra low frequency noise generated when the train enters or exits, especially in the tunnel T of the Shinkansen. is there.

As a result of the experiment, it has been found that the use of the gravel 2 used as an aggregate, which has a rounded surface, such as crushed stone, for example, improves the sound absorption, rather than that having a rounded surface. There was found. Further, the above plate 1 is a tunnel T
It can also be used as a gutter lid inside, and when used as a gutter lid as described above, for example, people can walk on it, and by providing water permeability, for example, tunnels Water flowing from the inner wall and flowing onto the plate 1 can also be smoothly passed through the plate 1 and into the side groove, and there is no danger that water will collect on the plate 1.

Therefore, the upper opening of the side groove is closed by the plate body 1 so that the water flowing into the plate body 1 is reliably discharged into the side groove while reliably preventing dust or the like from entering the side groove. Can be done. In the above embodiment, the plate 1 is used for the inner wall of the tunnel T or the lid of the gutter. However, the present invention is not limited to this. For example, the plate 1 may be used for a soundproof wall standing on a road side zone of a highway. It may be used for the inner side wall or the road surface of an underground shopping mall, or may be used as a floorboard laid on a sidewalk, flooring or a wallboard of a factory.

In the case of using as a floorboard, a flooring or a wallboard of a factory, for example, on an inner side wall or a road surface of an underground shopping mall, a sidewalk, or the like, a natural stone of beautiful color is used on the surface of the plate 1. It is preferable that the surface of the plate 1 is formed into a decorative surface by bonding with a transparent epoxy resin. In the above embodiment, the reinforcing bar 4 is embedded in the plate 1, but a reinforcing member made of, for example, a metal net or a plastic frame may be embedded instead of the reinforcing bar 4.

FIG. 4 shows an example in which the present invention is applied to a so-called sidewalk block which is provided at a boundary between a sidewalk and a road to separate the road from the sidewalk. A mixture of the gravel 2, Portland cement 3, and water weighing about 10 mm in weight and kneaded is poured into a predetermined mold and hardened, and has a porosity of about 30% and air permeability and water permeability. This is molded into a block body 10 having

Even with the above-described block body 10, it is possible to absorb the noise of the car, and it is also easier to break than the ordinary concrete one. Even at the time, the block body 10 is easily broken as compared with the ordinary concrete sidewalk block, and the collision energy of the vehicle can be absorbed by the block body 10 and the damaged block body 1
0 can be replaced and repair is easy.

In the above embodiments, the average particle size of the aggregate is 10 mm. However, the present invention is not limited to this. The average particle size of the aggregate may be in the range of 5 mm to 30 mm. . In the above embodiments, as the aggregate, gravel or crushed stone was used.However, the invention is not limited to this.For example, crushed concrete lump as industrial waste, or waste material of asphalt road surface laid on roads By reusing the gravel and crushed stones contained in the steel, the sound absorber can be provided at low cost, and it can contribute to the recycling of industrial waste.

In the above embodiment, Portland cement 3 is used as a bonding agent. However, the present invention is not limited to this. For example, an adhesive made of a synthetic resin material may be used as the bonding agent.

[0020]

As described above, according to the first aspect of the present invention, a large number of aggregates 2 having a particle size of 5 mm to 30 mm are joined together by a bonding agent 3 to form a porosity of 20%. %
By forming the plate 1 or the block 10 having an air permeability of 50% to 50%, a sound absorber having sufficient strength to withstand use even under bad conditions such as outdoors can be obtained.

According to the second aspect of the present invention, stone is used as the aggregate of the first aspect, and cement is used as the bonding agent. The body 1 or the block body 10 can be manufactured at low cost, and the rigidity of the plate body 1 or the block body 10 can be sufficiently increased. According to the third aspect of the present invention, the reinforcing member 4 such as a reinforcing bar is buried in the plate 1 or the block 10, so that the first or second aspect of the present invention is provided.
In addition to the functions and effects of the invention described above, the strength of the plate body 1 or the block body 10 is further increased, so that the plate body 1 or the block body 10 can be sufficiently used even under bad outdoor conditions.

According to the fourth aspect of the present invention, since the sound absorber has water permeability, rainwater or the like does not accumulate on the surface of the sound absorber when used outdoors.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a sound absorbing body according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the same.

FIG. 3 is an explanatory diagram showing a main part in an enlarged manner.

FIG. 4 is a schematic explanatory view in which the sound absorber according to the present invention is applied to an inner surface of a tunnel.

FIG. 5 is a schematic plan view showing a state of noise absorption by a sound absorber applied to the inner surface of the tunnel.

FIG. 6 is a schematic perspective view showing another embodiment of a sound absorbing body according to the present invention, with a part thereof being omitted;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate body 10 Block body 2 Gravel (aggregate) 3 Portland cement (joining agent) 4 Rebar (reinforcing material)

Claims (4)

[Claims] 1. A large number of aggregates (2) weighing 5 mm to 30 mm in particle size are joined together by a bonding agent (3),
A sound absorber characterized by being formed into a plate (1) or a block (10) having a porosity of 20% to 50% and air permeability. 2. An aggregate (2) made of stone, and a bonding agent (3).
2. The sound absorber according to claim 1, wherein the sound absorber comprises cement. 3. A sound absorber according to claim 1, wherein a reinforcing material (4) is embedded in the plate (1) or the block (10). 4. The method according to claim 1, wherein water permeability is provided.
The described sound absorber.