In order to rationally select materials and improve the sound absorption and sound insulation treatment of buildings, firstly, the sound insulation, sound insulation, sound absorbing materials and sound insulation materials are conceptually distinguished, which should be the primary basic problem in building noise control.
Most of the buildings in the 1980s and before, the partition walls mostly use clay bricks, and the 240mm clay brick walls have a sound insulation of more than 50dB, and the sound insulation effect is good. However, today's building partitions have undergone fundamental changes. On the one hand, for the need of environmental protection, clay bricks have been banned in buildings because clay bricks will destroy farmland; on the other hand, due to the new building system and high-rise buildings, the weight is light. To make the partition wall structure tend to be thin and light. The sound insulation of light walls is generally low, and single-walls generally do not reach 50dB. Usually below 45dB, which makes the sound insulation worse than traditional clay brick walls. At present, there are five main types of partition wall materials and components, and their sound insulation conditions are generally as follows:
(1). The sound insulation of the cast-in-place solid reinforced concrete wall with a thickness of 200mm or more on the concrete wall is close to that of the 240mm clay brick wall. The sound insulation of the 150-180mm thick concrete wall is about 47-48dB, but the reinforced concrete with an areal density of 200kg/m2 is porous. Board, the sound insulation is below 45dB.
(2). There are many types of block wall blocks, and there are load-bearing and non-load-bearing blocks according to their functions. Commonly used blocks mainly include concrete hollow and solid blocks such as ceramsite, fly ash, slag, sandstone, etc.; gypsum, calcium silicate and other blocks. The sound insulation of the block wall varies with the weight and thickness of the wall. The sound-insulating performance of the load-bearing block wall with the same areal density as the clay brick wall is similar to that of the clay brick wall. The sound insulation performance of the cement mortar plastering block filling wall is largely determined by the wall surface. The thickness of the plastering layer. The sound insulation of the 15mm~20mm thick cement mortar on both sides is about 43~48dB, and the soundproofing of the lightweight block wall with the areal density less than 80kg/m2 is usually below 40dB.
(3). The strips of the partition wall of the slab wall are usually 60mm~120mm, and the areal density is generally less than 80kg/m2. It has the advantages of light weight and convenient construction. The slab wall can be further divided into two categories: one is used Solid or porous strips made of inorganic cementitious materials and aggregates, such as (reinforced) lightweight aggregate concrete strips, autoclaved aerated concrete strips, steel mesh ceramsite concrete strips, gypsum strips, etc. The sound insulation of single-layer lightweight slatted walls is usually between 32 and 40 dB; the other is prefabricated sandwich slabs, such as concrete rockwool or pre-composited by dense surface materials and lightweight core materials in the production plant. Polystyrene sandwich strip, fiber cement board lightweight sandwich panel, etc. The sound insulation of prefabricated sandwich strip walls is usually between 35 and 44 dB.
(4). The thin-wall composite wall and thin-wall composite wall is a lightweight wall formed by fixing the thin plates on both sides of the keel at the construction site. The thickness of the thin plate is generally 6mm-12mm, the thin plate is used as a wall surface layer board, and the wall keel is filled with rock wool or glass wool. 3. The thin plate varieties include gypsum board, fiber gypsum board, fiber cement board, calcium calcium board, calcium magnesium board, etc.
The sound insulation of the thin plate itself is not high, and the sound insulation of the single-layer board is between 26 and 30 dB, and the double-layer hollow cotton-filled composite wall composed of light steel keel and rock wool (or glass wool) can be obtained. Good sound insulation. Their sound insulation is usually between 40 and 49dB. Increase the number of layers, the sound insulation of the wall can be greater than 50dB.
(5). The core material wall of the cement mortar surface layer is sprayed on the construction site, and then the cement mortar surface is sprayed on both sides of the core material board. Commonly used core plates are steel wire mesh polystyrene board, steel wire mesh rock wool board, and plastic hollow inner template.
The sound insulation of such walls is related to the type of core material and the thickness of the cement mortar. Their sound insulation is usually between 35 and 42 dB.
In summary, at present, there are quite a few light-weight partition walls at home and abroad with poor sound insulation performance. The sound insulation of single-walls can not meet the minimum sound insulation requirements of residential wall, and can only be used for the inner partition wall. In order to improve the sound insulation of lightweight partition walls, construction acoustics workers at home and abroad have carried out a lot of research work and accumulated certain experience [4~11]. The following are some basic characteristics and laws of wallboard sound insulation: The amount of sound insulation varies with the material. The sound insulation of a single layer of uniform and dense wall panels obeys the "sound quality law" of architectural acoustics, that is, the sound insulation is proportional to the weight per unit area of ​​the building. The surface density is doubled and the sound insulation is approximately Increase 4~5dB. When sound waves are projected on the wallboard, the heavy wall is less prone to vibration than the light wall. The low frequency is easy to excite vibration than the high frequency. Therefore, the heavy wall is better than the light wall, and the high frequency is better than the low frequency sound insulation. The surface density of lightweight partition walls is limited. To improve their sound insulation, double or multi-layer composite construction is applied.
2. The air layer is arranged with a double wall structure, and a certain air layer gap is left between the two walls. Due to the elastic layer of the air layer, the sound insulation of the total wall exceeds the mass law.
3. The application of sound absorbing materials places sound absorbing materials in the air layer of the double wall, which will further improve the sound insulation of the double wall. The greater the thickness of the sound absorbing material, the better the sound absorbing performance of the sound absorbing material, and the more significant the sound insulation. The sound-absorbing material is placed in the double-wall air layer. For the lightweight double-wall, the effect is more prominent in the double-wall. The Chinese home theater network welcomes you. It should be noted that the appearance of the acoustic bridge should avoid the rigid connection of the solid between the air layers of the double wall - the acoustic bridge. If there is a sound bridge, it will destroy the elastic layer of the air layer, so that the sound insulation is reduced. Hollow wall partition or The hollow part of the hollow block partition wall can reduce the weight of the wall, but it is not good for the sound insulation. For the hollow slab, the hollow building block and the like, and the built-in empty wall, the inner cavity cannot be mistaken. It is a layer of air that can be used for sound insulation. Because these cavities are surrounded by 100% rigid acoustic bridges, they do not have the elasticity of the air layer. Compared with solid plates, the same material has the same surface density. The amount of sound insulation will be lower than or approximately equal to the sound insulation of the latter.
5. The plastering layer can increase the sound insulation. The holes and gaps have a great adverse effect on the sound insulation. The fine holes and gaps on the wall will reduce the high frequency sound insulation. As the holes or gaps increase, the high frequency sound insulation will gradually decrease. And affect the expansion of the medium and low frequency. Some lightweight aggregate hollow block walls, due to the existence of a large number of interpenetrating small holes and slits in the block material, the block must be plastered on the wall surface after the masonry is completed (sealed ), otherwise the sound insulation is very low. For example, the wall of a 190mm thick ceramsite hollow block, the sound insulation is less than 20dB when the surface is not plastered, the thickness of the plaster layer is increased to 30mm, the sound insulation of the wall The amount reaches 50dB.
6. Plates of different materials can avoid "matching" phenomenon. When the wall plate is excited by sound waves for bending vibration, an anastomosis effect will occur in a certain frequency band, forming a sound insulation trough. The frequency of the anastomosis is not only related to the stiffness and surface density of the wallboard, but also increases with the thickness of the panel. Frequency shifting down. Two-layer thin-wall composite wall on both sides of the wall panel, two plates of different thickness or different materials are used to prevent the two plates from simultaneously matching, so that the matching valleys of the two panels are staggered to improve the sound insulation performance of the wall. .
Sound absorption, changing the characteristics of the indoor sound field for the same space. The main function of sound absorption is to absorb the reverberation sound in the room, which does not work for direct sound, that is to say, sound absorption can improve the sound quality, but the effect on noise reduction is not good; and the sound absorbing material is porous and evacuated, and the sound insulation is Density-based;
Sound insulation, relative to the two spaces, the main function of sound insulation is to block the sound from one space to another to prevent noise interference. The specific requirements of the soundproof material are: dense and non-porous, with a large weight.
However, in general, when noise reduction treatment is carried out, it is combined with suction and sound insulation, that is, noise and indoor noise are transmitted to the outside by sound insulation, and the reverberation sound in the room is adjusted by sound absorption. The envelope structure of the building such as the wall The sound insulation of doors, windows, slabs and roofs directly relates to outdoor traffic, construction and the introduction of noise from neighbors and the noise of factory production equipment, the high noise of indoor noise such as computer rooms and discos, affecting the surrounding environment. Therefore, the building sound insulation material is the technical guarantee for obtaining a quiet sound environment. The low ambient noise in the room is also the basic condition for good sound quality in the room. Sound insulation is to reduce the sound pressure level from the sound source to the destination. From the perspective of initiative, the sound insulation measures Both active and passive; but often passive methods are used—even if the energy is converted to another form of energy.
Most of the buildings in the 1980s and before, the partition walls mostly use clay bricks, and the 240mm clay brick walls have a sound insulation of more than 50dB, and the sound insulation effect is good. However, today's building partitions have undergone fundamental changes. On the one hand, for the need of environmental protection, clay bricks have been banned in buildings because clay bricks will destroy farmland; on the other hand, due to the new building system and high-rise buildings, the weight is light. To make the partition wall structure tend to be thin and light. The sound insulation of light walls is generally low, and single-walls generally do not reach 50dB. Usually below 45dB, which makes the sound insulation worse than traditional clay brick walls. At present, there are five main types of partition wall materials and components, and their sound insulation conditions are generally as follows:
(1). The sound insulation of the cast-in-place solid reinforced concrete wall with a thickness of 200mm or more on the concrete wall is close to that of the 240mm clay brick wall. The sound insulation of the 150-180mm thick concrete wall is about 47-48dB, but the reinforced concrete with an areal density of 200kg/m2 is porous. Board, the sound insulation is below 45dB.
(2). There are many types of block wall blocks, and there are load-bearing and non-load-bearing blocks according to their functions. Commonly used blocks mainly include concrete hollow and solid blocks such as ceramsite, fly ash, slag, sandstone, etc.; gypsum, calcium silicate and other blocks. The sound insulation of the block wall varies with the weight and thickness of the wall. The sound-insulating performance of the load-bearing block wall with the same areal density as the clay brick wall is similar to that of the clay brick wall. The sound insulation performance of the cement mortar plastering block filling wall is largely determined by the wall surface. The thickness of the plastering layer. The sound insulation of the 15mm~20mm thick cement mortar on both sides is about 43~48dB, and the soundproofing of the lightweight block wall with the areal density less than 80kg/m2 is usually below 40dB.
(3). The strips of the partition wall of the slab wall are usually 60mm~120mm, and the areal density is generally less than 80kg/m2. It has the advantages of light weight and convenient construction. The slab wall can be further divided into two categories: one is used Solid or porous strips made of inorganic cementitious materials and aggregates, such as (reinforced) lightweight aggregate concrete strips, autoclaved aerated concrete strips, steel mesh ceramsite concrete strips, gypsum strips, etc. The sound insulation of single-layer lightweight slatted walls is usually between 32 and 40 dB; the other is prefabricated sandwich slabs, such as concrete rockwool or pre-composited by dense surface materials and lightweight core materials in the production plant. Polystyrene sandwich strip, fiber cement board lightweight sandwich panel, etc. The sound insulation of prefabricated sandwich strip walls is usually between 35 and 44 dB.
(4). The thin-wall composite wall and thin-wall composite wall is a lightweight wall formed by fixing the thin plates on both sides of the keel at the construction site. The thickness of the thin plate is generally 6mm-12mm, the thin plate is used as a wall surface layer board, and the wall keel is filled with rock wool or glass wool. 3. The thin plate varieties include gypsum board, fiber gypsum board, fiber cement board, calcium calcium board, calcium magnesium board, etc.
The sound insulation of the thin plate itself is not high, and the sound insulation of the single-layer board is between 26 and 30 dB, and the double-layer hollow cotton-filled composite wall composed of light steel keel and rock wool (or glass wool) can be obtained. Good sound insulation. Their sound insulation is usually between 40 and 49dB. Increase the number of layers, the sound insulation of the wall can be greater than 50dB.
(5). The core material wall of the cement mortar surface layer is sprayed on the construction site, and then the cement mortar surface is sprayed on both sides of the core material board. Commonly used core plates are steel wire mesh polystyrene board, steel wire mesh rock wool board, and plastic hollow inner template.
The sound insulation of such walls is related to the type of core material and the thickness of the cement mortar. Their sound insulation is usually between 35 and 42 dB.
In summary, at present, there are quite a few light-weight partition walls at home and abroad with poor sound insulation performance. The sound insulation of single-walls can not meet the minimum sound insulation requirements of residential wall, and can only be used for the inner partition wall. In order to improve the sound insulation of lightweight partition walls, construction acoustics workers at home and abroad have carried out a lot of research work and accumulated certain experience [4~11]. The following are some basic characteristics and laws of wallboard sound insulation: The amount of sound insulation varies with the material. The sound insulation of a single layer of uniform and dense wall panels obeys the "sound quality law" of architectural acoustics, that is, the sound insulation is proportional to the weight per unit area of ​​the building. The surface density is doubled and the sound insulation is approximately Increase 4~5dB. When sound waves are projected on the wallboard, the heavy wall is less prone to vibration than the light wall. The low frequency is easy to excite vibration than the high frequency. Therefore, the heavy wall is better than the light wall, and the high frequency is better than the low frequency sound insulation. The surface density of lightweight partition walls is limited. To improve their sound insulation, double or multi-layer composite construction is applied.
2. The air layer is arranged with a double wall structure, and a certain air layer gap is left between the two walls. Due to the elastic layer of the air layer, the sound insulation of the total wall exceeds the mass law.
3. The application of sound absorbing materials places sound absorbing materials in the air layer of the double wall, which will further improve the sound insulation of the double wall. The greater the thickness of the sound absorbing material, the better the sound absorbing performance of the sound absorbing material, and the more significant the sound insulation. The sound-absorbing material is placed in the double-wall air layer. For the lightweight double-wall, the effect is more prominent in the double-wall. The Chinese home theater network welcomes you. It should be noted that the appearance of the acoustic bridge should avoid the rigid connection of the solid between the air layers of the double wall - the acoustic bridge. If there is a sound bridge, it will destroy the elastic layer of the air layer, so that the sound insulation is reduced. Hollow wall partition or The hollow part of the hollow block partition wall can reduce the weight of the wall, but it is not good for the sound insulation. For the hollow slab, the hollow building block and the like, and the built-in empty wall, the inner cavity cannot be mistaken. It is a layer of air that can be used for sound insulation. Because these cavities are surrounded by 100% rigid acoustic bridges, they do not have the elasticity of the air layer. Compared with solid plates, the same material has the same surface density. The amount of sound insulation will be lower than or approximately equal to the sound insulation of the latter.
5. The plastering layer can increase the sound insulation. The holes and gaps have a great adverse effect on the sound insulation. The fine holes and gaps on the wall will reduce the high frequency sound insulation. As the holes or gaps increase, the high frequency sound insulation will gradually decrease. And affect the expansion of the medium and low frequency. Some lightweight aggregate hollow block walls, due to the existence of a large number of interpenetrating small holes and slits in the block material, the block must be plastered on the wall surface after the masonry is completed (sealed ), otherwise the sound insulation is very low. For example, the wall of a 190mm thick ceramsite hollow block, the sound insulation is less than 20dB when the surface is not plastered, the thickness of the plaster layer is increased to 30mm, the sound insulation of the wall The amount reaches 50dB.
6. Plates of different materials can avoid "matching" phenomenon. When the wall plate is excited by sound waves for bending vibration, an anastomosis effect will occur in a certain frequency band, forming a sound insulation trough. The frequency of the anastomosis is not only related to the stiffness and surface density of the wallboard, but also increases with the thickness of the panel. Frequency shifting down. Two-layer thin-wall composite wall on both sides of the wall panel, two plates of different thickness or different materials are used to prevent the two plates from simultaneously matching, so that the matching valleys of the two panels are staggered to improve the sound insulation performance of the wall. .
Sound absorption, changing the characteristics of the indoor sound field for the same space. The main function of sound absorption is to absorb the reverberation sound in the room, which does not work for direct sound, that is to say, sound absorption can improve the sound quality, but the effect on noise reduction is not good; and the sound absorbing material is porous and evacuated, and the sound insulation is Density-based;
Sound insulation, relative to the two spaces, the main function of sound insulation is to block the sound from one space to another to prevent noise interference. The specific requirements of the soundproof material are: dense and non-porous, with a large weight.
However, in general, when noise reduction treatment is carried out, it is combined with suction and sound insulation, that is, noise and indoor noise are transmitted to the outside by sound insulation, and the reverberation sound in the room is adjusted by sound absorption. The envelope structure of the building such as the wall The sound insulation of doors, windows, slabs and roofs directly relates to outdoor traffic, construction and the introduction of noise from neighbors and the noise of factory production equipment, the high noise of indoor noise such as computer rooms and discos, affecting the surrounding environment. Therefore, the building sound insulation material is the technical guarantee for obtaining a quiet sound environment. The low ambient noise in the room is also the basic condition for good sound quality in the room. Sound insulation is to reduce the sound pressure level from the sound source to the destination. From the perspective of initiative, the sound insulation measures Both active and passive; but often passive methods are used—even if the energy is converted to another form of energy.
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