JP4398382B2 - Sound absorbing structure and track structure using the same - Google Patents

Description

  The present invention makes use of the excellent sound absorbing function of the recycled material itself (function to absorb and reduce sound), and the recycled material does not scatter as a whole, has a water permeability function, is flame retardant, and can be manufactured at low cost. The present invention relates to a sound absorbing structure that is easy to construct and a track structure that reduces noise using the sound absorbing structure.

  For the purpose of reducing noise generated from railway trains and automobiles, sound absorbing materials are used for railway tracks, sound barriers of highways, and the like. For example, conventionally, as a measure for preventing noise generated from a slab track during traveling of a train, a method of providing a recess in the track slab and spraying a roadbed ballast or the like there has been used.

FIG. 4 is a diagram showing a trajectory subjected to a conventional roadbed ballast spraying method. (A) is a plan view, (B) is a side sectional view, and (C) is a front sectional view. The surface of the track slab 41 is provided with concave portions 43 (depth 13 cm, width 20 to 30 cm) in a row, and the road bed ballast 42 (particle size 1.9 to 6.4 cm) is laid in the concave portion 43. It has been. A roadbed ballast 42 is also stacked on the side of the track slab 41.
The above-mentioned roadbed ballast laying method has a low noise reduction effect if the spreading thickness of the roadbed ballast 42 is thin, and if the spreading thickness of the roadbed ballast 42 is increased, the rail position becomes high and uneconomical.

Further, a method of installing a sound absorbing material formed of foamed lightweight concrete or ceramic on the upper surface of the track slab is adopted.
FIG. 5 is a cross-sectional view showing a track subjected to a conventional sound absorbing material laying method. A sound absorbing material 51 is laid around the rail 32 on the upper surface of the track slab 31.
The above-mentioned sound absorbing material laying method has a certain noise reduction effect, but generally, the sound absorbing material is expensive (for example, a foamed concrete board having a thickness of 60 mm is about 10,000 yen / m ² ), so that the construction cost is high. There is.

  On the other hand, Patent Document 1 discloses a general waste for the purpose of providing a noise-reducing track structure having a low noise reduction effect even when the construction cost is low and the sound absorption layer is thin (for example, 10 cm or less). A noise-reducing track structure using a recycled material, characterized in that it has a layer of a recycled material substantially made of inorganic particles produced by pulverizing and classifying the incineration residue, is described. In addition, in Patent Document 1, in order to prevent scattered recycled materials from scattering, a method of spreading a connecting material such as a resin to solidify the surface of the recycled material layer, a method of covering the surface portion of the recycled material layer with a net, Alternatively, a method is described in which the bag is packed in a fine bag and arranged on the upper surface of the track slab. The document also describes a method for manufacturing a recycled material layer in advance as a molded product having a predetermined shape in a factory.

  By the way, in recent years, the reuse of resources has become an important issue from the viewpoint of environmental protection, etc. Clinker ash, a type of coal ash that is produced when coal is burned at a thermal power plant, is about half the amount of land. Although used as a building material, the remainder was disposed of in landfill (see Non-Patent Document 1).

JP-A-8-068001 Environmental Action Report 2004, Technology Development for Effective Use of Waste, [online], Tohoku Electric Power Co., Inc. [searched on November 2, 2004], Internet <URL: http: // www. tohoku-epco. co. jp / enviro / tea2004 / 03 / 03c. htm>

In the noise reduction type track structure described in Patent Document 1, in order to prevent the recycled material from scattering, a method of solidifying the surface of the recycled material layer by spraying a connecting material such as resin, the surface portion of the recycled material layer is connected to the net. In the case of using the method of covering with or the method of packing in a fine bag etc. and arranging on the upper surface of the track slab, the sound absorption effect can be expected if there is enough space between the particles of the recycled material. It takes a lot of manpower, and the sound absorption effect cannot be expected unless the various methods described above are appropriately selected depending on the particle size of the recycled material. In addition, the method of hardening the surface with a connecting material also has a problem that the connecting agent has a resin as a main component so that it easily burns.
Patent Document 1 describes a method of manufacturing a recycled material layer as a molded product having a predetermined shape in a factory in advance. However, if the recycled material layer is formed as a resin molded product, a sufficient air portion cannot be provided and a sound absorbing effect is obtained. I can not expect.

  The present invention makes use of the excellent sound absorbing function of the recycled material itself, and has a water-permeable function without scattering of the recycled material as a whole, is flame retardant, can be manufactured at low cost, and is easy to construct. The purpose is to provide.

  As a result of intensive studies, the inventor has a sound absorbing structure including a case main body provided with a sound wave incident port and a drain port, and a sound absorbing material filled in an internal space of the case main body, wherein the sound wave incident Each of the mouth and the drain port is provided with a porous lid, and the case main body is composed of clinker ash having an average particle size of 0.05 mm to less than 2 mm joined by a binder, and the porous lid Each of the bodies is composed of clinker ash having an average particle diameter of 2 mm to 20 mm bonded with a binder, and the sound absorbing material is composed of clinker ash having an average particle diameter of 2 mm to 20 mm; Then, it was found that it has an excellent sound absorption function and water permeability function, is flame retardant, can be manufactured at low cost, and is easy to construct, and thus completed the present invention.

  That is, the present invention provides the following (1) to (8).

(1) A sound absorbing structure having a case main body provided with a sound wave incident port and a drain port, and a sound absorbing material filled in the internal space of the case main body,
A porous lid is provided for each of the sound wave incident port and the drain port,
The case body is composed of clinker ash having an average particle size of 0.05 mm to less than 2 mm bonded with a binder,
Each of the porous lids is composed of clinker ash having an average particle diameter of 2 mm to 20 mm bonded with a binder,
The sound absorbing material is a sound absorbing structure made of clinker ash having an average particle diameter of 2 mm to 20 mm.

  (2) The sound absorbing structure according to (1), wherein 70 to 80% of the total mass of the sound absorbing structure is clinker ash.

  (3) The sound absorbing structure according to (1) or (2), wherein 35 to 50% of the mass of the case body is clinker ash.

  (4) The sound-absorbing structure according to any one of (1) to (3), wherein the case main body is made of a water-impermeable molded product obtained by molding a mixture of clinker ash and a binder.

  (5) The sound absorbing structure according to any one of (1) to (4), wherein 80 to 90% of the mass of the lid is clinker ash.

  (6) The sound absorbing structure according to any one of (1) to (5), wherein each of the lids is made of a porous molded product obtained by molding a mixture of clinker ash and a binder. .

(7) The sound absorbing structure according to any one of (1) to (6), wherein the apparent specific gravity of the clinker ash is 0.6 to 1.1 g / cm ³ .

  (8) A track structure including a rail on which a train travels and the sound absorbing structure according to any one of (1) to (7) installed between the rails.

The sound absorbing structure of the present invention utilizes the excellent sound absorbing function of the clinker ash itself, and has a water permeable function without scattering of the clinker ash as a whole, is flame retardant, can be manufactured at low cost, and is easy to install. is there.
The track structure of the present invention can significantly reduce noise generated from a train as compared with a conventional track structure. Moreover, even when it is flooded due to rain or the like, noise can be stably reduced because it has an excellent water permeability function. Furthermore, the track structure of the present invention is easier to construct than the conventional roadbed ballast laying method or the like.

  Hereinafter, although the sound-absorbing structure of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings, the present invention is not limited to these preferred embodiments.

FIG. 1 is a schematic cross-sectional view of an embodiment of a sound absorbing structure of the present invention.
The sound absorbing structure 10 of the present invention is installed inside a case main body 13 having a sound wave incident port 11 and a drainage port 12 on two opposed surfaces, respectively, so that the lower lid 14 covers the drainage port 12. The sound absorbing material 15 is filled in the internal space 13, and the upper lid body 16 is installed so as to cover the sound wave incident port 11 from the inside of the case main body 13.
Usually, the sound absorbing structure 10 of the present invention is horizontally installed such that the sound wave incident port 11 is on the upper side (noise source side) and the drain port 12 is on the lower side. In this specification, for the sake of convenience, the description will be made with the sound wave incident port 11 side as the upper side and the drainage port 12 side as the lower side. The sound absorbing structure 10 of the present invention is not limited to being installed horizontally, but may be installed vertically or obliquely as a wall material or the like.

The case main body 13 has a sound wave incident port 11 and a drainage port 12, has an internal space, and is composed of clinker ash having an average particle diameter of 0.05 mm to less than 2 mm combined with a binder.
The shape of the case body 13 is not particularly limited, and examples thereof include a rectangular parallelepiped and a cylindrical shape.

The case body 13 is tightly filled with clinker ash having a relatively small particle diameter, and the gap is filled with a binder, so that it is water-impermeable and has excellent mechanical strength against external stress.
In addition, the amount of binder used can be suppressed by the effect of close packing, and the amount of clinker ash, which is a non-combustible material, is relatively increased. Therefore, an excellent difficulty with a critical oxygen index of about 45 can be obtained without adding a flame retardant. Flammability is obtained.
Here, since the critical oxygen index of the case body similarly prepared using clinker ash having an average particle size of 2 mm or more is about 30, an improvement in flame retardance of 30% or more can be expected.
In view of these characteristics, the average particle diameter of the clinker ash used for the case body 13 is preferably 0.05 mm to less than 2 mm, and more preferably 0.5 to 1.0 mm.

The apparent specific gravity of clinker ash is preferably 0.6~1.1g / cm ³ used in the case body 13, and more preferably 0.8~1.0g / cm ^3. When the apparent specific gravity is within this range, the sound-absorbing structure of the present invention becomes relatively light and construction becomes easy.
In the present specification, the apparent specific gravity means the mass of clinker ash / the volume of clinker ash. Here, the volume of the clinker ash refers to the total volume including the gaps of the clinker ash in a state where the clinker ash is not pressurized and compressed.
Means.

  It is preferable that 35 to 50% of the mass of the case body 13 is clinker ash. Within this range, the strength and flame retardancy of the case body 13 can be maintained in a high balance. In particular, when the average particle size of the clinker ash is 0.5 to 1 mm, it is particularly preferable that 40 to 50% of the mass of the case main body 13 is clinker ash because of excellent characteristics.

In the present specification, clinker ash refers to silica (SiO ₂ ) and alumina (Al) obtained by pulverizing a porous lump formed by coal ash produced by combustion in a boiler of a thermal power plant by a pulverizer or the like. ₂ O ₃ ) is a main porous material. Clinker ash has the same particle size distribution and hydraulic conductivity as sand, and has excellent water permeability. Furthermore, clinker ash has an excellent sound absorbing function.

  The case main body 13 is formed of clinker ash having a relatively small average radius, which is obtained by classifying clinker ash having a particle size distribution using a sieve or the like and bonded with a binder. A material having a relatively large average particle diameter is used for the lid bodies 14 and 16 and the sound absorbing material 15. That is, the sound absorbing structure 10 of the present invention satisfies the required characteristics by using clinker ash having a different particle size for each member. Therefore, since all particle sizes of clinker ash are used, there is an advantage that almost no secondary industrial waste is generated.

The binding material is not limited as long as it is a resin or an adhesive that can be bonded to clinker ash. Specifically, for example, vinyl ester resins such as epoxy acrylate resins, epoxy resins, unsaturated polyester resins, phenol resins, acrylic resins, and the like, epoxy adhesives, acrylic adhesives, vinyl adhesives, carbohydrates Examples thereof include adhesives such as system glues.
Among these, vinyl ester resins are preferable from the viewpoints of weather resistance, mechanical strength, and chemical resistance.

The sound wave incident port 11 of the case body 13 serves as an entrance for noise into the sound absorbing structure. Further, when rainwater or the like enters the sound absorbing structure through the sound wave incident port 11 when the sound absorbing structure 10 of the present invention is installed outdoors, the water can be discharged from the drain port 12.
As shown in FIG. 1, the opening of the case body 13 includes a sound wave incident port 11 on the upper surface of the case body 13, and a drain port 12 on the bottom surface of the case body 13. The sound wave incident port 11 is preferably larger than the drain port 12. However, the shape, size, and position are not particularly limited when there are two or more sonic wave incident ports 11 and drain ports 12. Examples of the shape of the opening include a quadrangle and a circle. Moreover, you may have many small opening parts (for example, about 1 cm in diameter) in the whole bottom face of the case main body 13. FIG.

  When the sound wave incident port 11 and the drainage port 12 are respectively positioned on the two opposing surfaces of the case body 13, for example, when installed horizontally outdoors, rainwater that has entered from the sound wave incident port 11 efficiently passes through the drainage port 12. Drained. Therefore, it is possible to prevent the sound absorbing function from being deteriorated due to the pores of the sound absorbing material 15 being blocked with rainwater.

  Moreover, in the sound absorbing structure 10 of the present invention, the sound absorbing material 15 filled in the internal space of the case body 13 has a particularly excellent sound absorbing function. It is preferable to take in inside. Therefore, it is preferable that the sound wave incident port 11 is as large as possible. On the other hand, the drain port 12 is preferably as small as possible within a range in which a certain level of drainage can be maintained from the viewpoint of excellent sound absorbing function.

  The case main body 13 described above may contain other materials other than the clinker ash and the binder as long as the characteristics of the present invention are not impaired. Examples of other materials include flame retardants, fillers, and fiber base materials such as glass, carbon, aramid, basalt, and vinylon.

  The upper lid body 16 and the lower lid body 14 are lid bodies installed so as to cover the sound wave incident port 11 and the drainage port 12, respectively, and are composed of clinker ash having a relatively large average particle diameter, which is coupled with a binder. Has been. Therefore, the lids 14 and 16 have a function of blocking the sound absorbing material 15 from coming out of the case main body 13, a sound passing function, a water permeability function, and a gap (hole) between particles of the clinker ash. A sound absorbing function is imparted to the sound absorbing structure 10 of the present invention. From the point which is excellent by the balance of these characteristics, 5-18 mm is preferable and, as for the average particle diameter of the clinker ash which comprises the cover bodies 14 and 16, 10-15 mm is more preferable.

  It is preferable that 80 to 90% of the mass of the lid bodies 14 and 16 is clinker ash. Within this range, there will be moderate holes, and the sound absorbing material 15 will be excellent in balance between the function of blocking the sound absorbing material 15 from coming out of the case body, the sound passing function, the water permeability function and the sound absorbing function. In addition, when the sound absorbing structure of the present invention is used for a track structure of a train, it is possible to maintain a mechanical strength that does not cause damage even if an operator walks on for walking. It is particularly preferable that 80 to 85% of the masses of the lid bodies 14 and 16 are clinker ash because they are more excellent in these characteristics.

The apparent specific gravity of the clinker ash used for the lid bodies 14 and 16 is preferably 0.6 to 1.1 g / cm ³ . When the apparent specific gravity is within this range, the sound-absorbing structure 10 of the present invention becomes relatively light and construction becomes easy. In particular, when the average particle diameter of clinker ash is 5 to 18 mm and the apparent specific gravity is 0.6 to 0.8 g / cm ³ , the above properties are more excellent.

  As the bonding material constituting the lids 14 and 16, the same bonding material as that used for the case body 13 described above can be used.

  The porosity of the lid bodies 14 and 16 is preferably 40 to 80%, and more preferably 50 to 70%. If it is within this range, it will have appropriate holes, and it will have an excellent balance of the function of blocking the sound absorbing material 15 from coming out of the case body, the sound passing function, the water permeability function and the sound absorbing function. Can hold.

The shapes and sizes of the lids 14 and 16 are not particularly limited as long as they can cover the sound wave incident port 11 and the drainage port 12 of the case body 13. Examples of the shape include a quadrangle and a circle.
The thickness of the lids 14 and 16 is not particularly limited, but is preferably 5 to 20 mm, and more preferably 6 to 15 mm. Within these ranges, the balance of mechanical strength, sound transmission function, water permeability function and sound absorption function is excellent.

  In the sound absorbing structure 10 of the present invention, the lids 14 and 16 are installed inside the case main body 13, but may be installed so as to cover the sound wave incident port 11 and the drainage port 12 from the outside.

  The above-mentioned lids 14 and 16 may contain materials other than the clinker ash and the binder as long as the characteristics of the present invention are not impaired. Examples of other materials include flame retardants, fillers, and fiber base materials such as glass, carbon, aramid, basalt, and vinylon.

The sound absorbing material 15 is filled in the internal space of the case main body 13 and is stored by the lid bodies 14 and 16 so as not to be scattered from the sound wave incident port 11 and the drain port 12.
The sound absorbing material 15 is clinker ash having an average particle diameter of 2 mm to 20 mm. As described above, there is a problem that the sound absorbing function is not sufficiently exhibited when pores existing on the clinker ash surface are blocked by rainwater or the like, but if the average particle size is in the above range, it has an excellent water permeability function. Therefore, such a decrease in sound absorption function can be suppressed, and a stable sound absorption function can be exhibited. In view of these characteristics, the average particle diameter of the clinker ash of the sound absorbing material 15 is preferably 3 to 15 mm.

  Moreover, since the sound absorbing material 15 is not bonded with a binding material, it can exhibit an excellent sound absorbing function and water permeability function. Furthermore, since the clinker ash itself is nonflammable, flame retardancy can be imparted to the sound absorbing structure of the present invention.

The apparent specific gravity of the clinker ash of the sound absorbing material 15 is preferably 0.6 to 1.1 g / cm ³ . When the apparent specific gravity is within this range, the sound-absorbing structure of the present invention becomes relatively light and construction becomes easy. In particular, when the average particle diameter of clinker ash is 3 to 15 mm and the apparent specific gravity is 0.7 to 0.9 g / cm ³ , the above properties are more excellent.

  The sound absorbing material 15 may contain other materials other than the clinker ash as long as the characteristics of the present invention are not impaired, but is preferably made of only the clinker ash. Examples of other materials include materials having sound absorption characteristics such as glass wool and urethane foam.

  It is preferable that 70 to 80% of the total mass of the sound absorbing structure 10 of the present invention is clinker ash. When the clinker ash is contained in this range, excellent flame retardancy can be obtained while maintaining the required mechanical strength. Moreover, effective use of clinker ash, which is industrial waste, can be substantially achieved, and can be an object of Eco Mark products. From these points, it is more preferable that 75 to 80% is clinker ash.

  Since the sound absorbing structure 10 of the present invention described above has a water permeability function from the sound wave incident port 11 to the drain port 12, the sound absorbing function can be stably exhibited, and also when the sound absorbing structure 10 of the present invention is submerged. Since it does not float on the water, it can be installed in places where water tends to accumulate.

  In the sound absorbing structure 10 of the present invention, the sound absorbing material 15 mainly functions as a sound absorbing material and exhibits a sound absorbing function. The lids 14 and 16 themselves have a sound absorbing function. Furthermore, the sound absorbing structure 10 of the present invention has a structure in which the sound absorbing function of the sound absorbing material 15 does not deteriorate because the sound absorbing material 15 is not hardened by the binder. Further, when the lid bodies 14 and 16 contain clinker ash in the above ratio, the amount of the binder is relatively small, so that the sound absorbing function of the lid body is reduced due to the pores of the clinker ash being blocked. Can be suppressed.

  The manufacturing method of the sound absorbing structure 10 of the present invention is not particularly limited. For example, a mixture of a clinker ash having a predetermined particle size and a binder is poured into each mold and molded. The upper lid body 16 and the lower lid body 14 are formed. Next, the lower lid 14 is fixed to the inside of the case body 13 with an adhesive or the like so as to cover the drain port 12, and the sound absorbing material 15 is filled in the internal space of the case body 13. Next, the upper lid body 16 is fixed with an adhesive or the like so as to cover the sound wave inlet 11 from the inside of the case body 13, and the sound absorbing structure 10 of the present invention is obtained.

FIG. 2 is a schematic cross-sectional view of another embodiment of the sound absorbing structure of the present invention.
In FIG. 2, the case main body 21 is configured by a combination of an upper case main body 211 and a lower case main body 212, has a sound wave incident port 22 and a drainage port 23, and houses the sound absorbing material 24 in the internal space of the case main body 21. The upper lid body 25 and the lower lid body 26 are installed so as to cover the sound wave incident port 22 or the drainage port 23, respectively. The sound absorbing structure 20 of the present invention is installed inside the lower case body 212 so that the lower lid body 26 covers the drain port 23, and the sound absorbing material 24 is filled inside the lower case body 212, so The upper case main body 211 in which the upper cover body 25 is installed so as to cover 22 from the inside is combined with the lower case main body 212.

The upper case main body 211 and the lower case main body 212 have a sound wave incident port 22 and a drainage port 23, respectively, and are composed of a clinker ash having an average particle diameter of 0.05 mm to less than 2 mm and a binder.
The shape of the case main body 21 (the shape of the sound absorbing structure 20 of the present invention) is not particularly limited, and examples thereof include a rectangular parallelepiped and a cylindrical shape.
The upper surface of the upper case body 211 is provided with a sound wave incident port 22, and the side surface 211 a is preferably thinned as it is lowered downward, and the cross-sectional shape of the side surface 211 a as a whole is preferably a wedge shape. It is preferable that the drain port 23 is provided on the bottom surface of the lower case main body 212, and the side surface 212a is thinned as it rises upward, so that the cross-sectional shape of the side surface 212a becomes a wedge shape as a whole. Moreover, it is preferable that the front-end | tip part of the side surface 211a and the side surface 212a is round from a viewpoint of assembly workability | operativity.
With such a structure, the upper case main body 211 and the lower case main body 212 can be easily removed from the mold. Further, when the upper case body 211 and the lower case body 212 are combined, the side surface 211a of the upper case body and the side surface 212a of the lower case body are in close contact, and the upper case body 211 and the lower case body 212 are difficult to be detached. Further, a fixing means such as providing a convex portion on the side surface 211a of the upper case body and providing a concave portion in which the convex portion is fitted on the side surface 212a of the lower case main body may be provided.

The material constituting the case body 21 is the same as the material of the case body 13 described with reference to FIG. In addition, the sound wave incident port 22 and the drain port 23 have the same size and shape as the sound wave incident port 11 and the drain port 12 described in FIG.
The lid bodies 25 and 26 are the same as the lid bodies 14 and 16 described in FIG. In the sound absorbing structure 20 of the present invention, the lower lid 26 is installed inside the case main body 21, but may be installed so as to cover the drain outlet 23 from the outside.
The sound absorbing material 24 is the same as the sound absorbing material 15 described in FIG.

  As described above, the sound absorbing structure of the present invention can be used outdoors or in places where there is a concern about the presence of fire due to littering of cigarettes, etc. because of its excellent sound absorbing function and water permeability function and high flame retardancy. Specifically, it can be used for, for example, a sound absorbing material installed between railroad rails traveling outdoors or indoors, a sound absorbing material for exteriors such as a wall surface material, a sound insulating wall of an expressway, and the like.

Next, although the track structure of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings, the present invention is not limited to these preferred embodiments.
FIG. 3 is a perspective view of an embodiment of the track structure of the present invention.
In FIG. 3, 31 is a track slab, 32 is a rail, and the above-described sound absorbing structure 33 of the present invention is arranged side by side as a sound absorbing material on the track slab between the rails. On the upper surface of the sound absorbing structure 33 of the present invention, a rope-shaped member 34 is stretched over the surface of the sound absorbing structure of the present invention, and both ends of the rope-shaped member 34 are bound to anchor bolts 35 on the track slab side. .
In the illustrated example, the sound absorbing structures 33 according to the present invention are arranged two by two between the rails, but may be one, or may be three or more.

The fixing means for fixing the sound absorbing structure 33 of the present invention is not particularly limited, and examples include means for locking the tip of the rope-shaped member 34 to the anchor bolt 35 shown in FIG. Examples of the rope-shaped member 34 include a rope and a band. In the embodiment shown in FIG. 3, a rope is used.
Other fixing means include, for example, means for directly fixing the sound absorbing structure 33 of the present invention to the track slab 31 using anchor bolts; and bonding the sound absorbing structure 33 of the present invention to the track slab 31 using an adhesive. Means: Means for covering and fixing the sound absorbing structure 33 of the present invention with a net can be mentioned, and these fixing means can be used in combination.

  As described above, since the sound absorbing structure of the present invention has an excellent sound absorbing function, the track structure of the present invention can reduce noise generated from a train as compared with a conventional track structure. Further, even when submerged by rain or the like, the sound absorbing structure of the present invention has an excellent water permeability function, so that noise can be stably reduced. Furthermore, the sound absorbing structure of the present invention is relatively light weight, and the track structure of the present invention only fixes the sound absorbing structure of the present invention side by side between the track rails. Construction is easy.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Normal incidence sound absorption measurement test>
FIG. 6 is a cross-sectional view of a specimen used for a normal incidence sound absorption coefficient measurement test.
Using two types of test bodies (impedance tube A (for low frequency) and impedance tube B (for high frequency)) in which a lower lid 62, a sound absorbing material layer 64, and an upper lid 66 are laminated as shown in FIG. The normal incident sound absorption coefficient was measured.
Hereinafter, the method of the normal incidence sound absorption coefficient measurement test will be described in detail.

(Creation of impedance tube A)
As shown in FIG. 6, clinker ash (made by Tohoku Electric Power Industry Co., Ltd., the same shall apply hereinafter) having a particle diameter of 5 to 15 mm and vinyl ester in an aluminum pipe 60 having a length of 70 mm, a diameter of 90 mm, and a tube wall thickness of 3 mm. Resin (manufactured by Nippon Iupika Co., Ltd., hereinafter the same) is mixed in a mass ratio (clinker ash / vinyl ester resin) 5/1, filled to a height of 10 mm, cured at 25 ° C. for 2 hours, The lower lid 62 having a rate of 67% was formed. Next, a clinker ash having a particle size of 5 to 10 mm was spread on the lower lid 62 so as to have a height of 50 mm, and the sound absorbing material layer 64 was formed. Next, the same material as that used for the lower lid 62 is filled on the sound absorbing material layer 64 so as to have a height of 10 mm, cured at 25 ° C. for 2 hours, and the upper lid having a porosity of 67%. 66 was formed to produce an impedance tube A. Similarly, impedance tube A was prepared, and a total of three specimens were prepared.
The porosity of the lid was calculated by injecting water into the lid just before overflowing, and dividing the volume of the water by the volume of the lid.

(Creation of impedance tube B)
Similarly, as shown in FIG. 6, a mass ratio (clinker ash / clinker ash / vinyl ester resin) of clinker ash having a particle diameter of 5 to 15 mm is placed in an aluminum pipe 68 having a length of 70 mm, a diameter of 38 mm, and a tube wall thickness of 2 mm. Vinyl ester resin) was mixed at 5/1, filled to a height of 10 mm, and cured at 25 ° C. for 2 hours to form a lower lid 62 having a porosity of 67%. Next, a clinker ash having a particle size of 5 to 10 mm was spread on the lower lid 62 so as to have a height of 50 mm, and the sound absorbing material layer 64 was formed. Next, the same material as that used for the lower lid 62 is filled on the sound absorbing material layer 64 so as to have a height of 10 mm, cured at 25 ° C. for 2 hours, and the upper lid having a porosity of 67%. 66 was formed to produce an impedance tube B. Similarly, impedance tube B was prepared, and a total of three specimens were prepared.
The porosity of the lid was measured by the same method as described above.

Using the three impedance tubes A created as described above, in accordance with JIS A1405-1998 under the conditions of 23 ° C., 1021 hPa, and back air layer 0 mm, in the range of 1/3 octave band center frequency 100 to 2000 Hz, Each normal incidence sound absorption coefficient was measured. The results and the average values of the three specimens are shown in FIG.
Similarly, using the three impedance tubes B created as described above, each normal incident sound absorption coefficient was measured in the range of 1/3 octave band center frequency 800 to 5000 Hz. The results and the average value of the three specimens are shown in FIG.

  As is apparent from the results shown in FIGS. 7 and 8, the impedance tube A has a normal incident sound absorption coefficient of 0.44 to 0.88 at a center frequency of 500 Hz to 2000 Hz, and the impedance tube B has a center frequency of 800 to 5000 Hz. The normal incident sound absorption coefficient was 0.40 to 0.91, and the sound absorption effect was sufficient. Therefore, even when the lid was used, it had a normal incident sound absorption coefficient comparable to the clinker ash itself.

<Bend strength test of case body>
Clinker ash having a particle diameter of 0.5 to 1 mm and vinyl ester resin are mixed at a mass ratio (clinker ash / vinyl ester resin) 1/1, and this mixture is filled in a mold and cured at 25 ° C. for 2 hours. A rectangular parallelepiped test body, which is the case body, was prepared. Each obtained specimen had the thickness and width shown in Table 1 below.
Using each of the obtained specimens, the bending strength and the flexural modulus were measured according to JIS K6911-1995.
The results are shown in Table 1.

<Shear strength test of case body>
Clinker ash having a particle diameter of 0.5 to 1 mm and vinyl ester resin are mixed at a mass ratio (clinker ash / vinyl ester resin) 1/1, and this mixture is filled in a mold and cured at 25 ° C. for 2 hours. A rectangular parallelepiped test body, which is the case body, was prepared. Each obtained specimen had a thickness and a width shown in Table 2 below.
Using each of the obtained specimens, the shear strength was measured according to JIS K6911-1995.
The results are shown in Table 2.

<Compression strength test of case body>
Clinker ash having a particle diameter of 0.5 to 1 mm and vinyl ester resin are mixed at a mass ratio (clinker ash / vinyl ester resin) 1/1, and this mixture is filled in a mold and cured at 25 ° C. for 2 hours. Then, a flat test body as a case body was prepared. Each obtained specimen had a width, a length and a cross-sectional area shown in Table 3 below.
The compressive strength was measured according to JIS K6911-1995 using each obtained test body.
The results are shown in Table 3.

  As is clear from the results shown in Tables 1, 2, and 3, each specimen had excellent strength. The case main body used for the sound absorbing structure of the present invention is made of basically the same material, composition and thickness as the test body used in each of the strength tests described above. Therefore, when the sound-absorbing structure of the present invention is used for a track structure of a train, it is possible to maintain a mechanical strength that does not cause damage even when an operator walks on for maintenance.

FIG. 1 is a schematic cross-sectional view of an embodiment of a sound absorbing structure of the present invention. FIG. 2 is a schematic cross-sectional view of another embodiment of the sound absorbing structure of the present invention. FIG. 3 is a perspective view of an embodiment of the track structure of the present invention. FIG. 4 is a diagram showing a track on which a conventional roadbed ballast laying method is applied. FIG. 5 is a cross-sectional view showing a track subjected to a conventional sound absorbing material laying method. FIG. 6 is a cross-sectional view of a specimen used for a normal incidence sound absorption coefficient measurement test. FIG. 7 is a graph showing the results of a normal incidence sound absorption coefficient measurement test using the impedance tube A. FIG. 8 is a graph showing the results of a normal incidence sound absorption coefficient measurement test using the impedance tube B.

Explanation of symbols

10, 20, 33 Sound absorbing structure of the present invention 11, 22 Sound wave inlet 12, 23 Drain 13, 13, Case main body 14, 26, 62 Lower lid 15, 24 Sound absorbing material 16, 25, 66 Upper lid 211 Upper Case body 211a Side surface of upper case body 212 Lower case body 212a Side surface of lower case body 31, 41 Track slab 32 Rail 34 Rope-shaped member 35 Anchor bolt 42 Road floor ballast 43 Recess 51 Sound absorbing material 60, 68 Aluminum pipe 64 Sound absorbing material layer

Claims (8)

A sound absorbing structure having a case main body provided with a sound wave incident port and a drain port, and a sound absorbing material filled in the internal space of the case main body,
A porous lid is provided for each of the sound wave incident port and the drain port,
The case body is composed of clinker ash having an average particle size of 0.05 mm to less than 2 mm bonded with a binder,
Each of the lids is composed of clinker ash having an average particle diameter of 2 mm to 20 mm bonded with a binding material,
The sound absorbing material is a sound absorbing structure made of clinker ash having an average particle diameter of 2 mm to 20 mm.   The sound absorbing structure according to claim 1, wherein 70 to 80% of the total mass of the sound absorbing structure is clinker ash.   The sound-absorbing structure according to claim 1 or 2, wherein 35 to 50% of the mass of the case body is clinker ash.   The sound-absorbing structure according to any one of claims 1 to 3, wherein the case body is made of a water-impermeable molded product obtained by molding a mixture of clinker ash and a binder.   The sound-absorbing structure according to any one of claims 1 to 4, wherein 80 to 90% of the mass of the lid is clinker ash.   The sound absorbing structure according to any one of claims 1 to 5, wherein each of the lid bodies is made of a porous molded article obtained by molding a mixture of clinker ash and a binder. The sound absorbing structure according to any one of claims 1 to 6, wherein an apparent specific gravity of the clinker ash is 0.6 to 1.1 g / cm ³ .   A track structure having a rail on which a train travels and the sound absorbing structure according to claim 1 installed between the rails.

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