• Journal of Environmental Science International
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• v.11 no.3
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• pp.235-240
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• 2002

The blocks using flyash were prepared in this study. The characteristic of sound absorption of flyash block was investigated. It was revealed that the chemical additives and flyash played an important role to determine the characteristic of sound absorption. Chemical additive affects the capability of sound absorption while flyash affects the characteristic of sound absorption, i.e. high value of the sound absorption coefficient at the specific frequencies(1KHz and 2KHz). The flyash block showed higher sound absorption coefficient than that of the commercial concrete block having carpet on the surface. It was also shown that the sound absorption coefficient increases with increase of the content of flyash in the block. However, it was found that the 70wt% of flyash in the flyash block was the optimum content to obtain the highest sound absorption coefficient.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.830-839
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• 2008

This study is designed to manufacture the upgraded sound absorption concrete by using foamed concrete by using artificial light weight aggregate which raises the continuous void ratio to increase the sound absorption ratio and improve the strength. In manufacturing the sound absorption block, the pre-foaming form is applied to generate continuous voids, controlling the density by the addition of bubbles. It is general that the more porosity creates, the weaker strength becomes. Each of specimens are used for this experiment and measured their absorption ratio to examine the absorption property depending on frequency. As a results of experiment, it is evaluated that the absorption capacity of the sound absorption block has relation to compression strength and surface shape.

• KIEAE Journal
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• v.7 no.3
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• pp.57-62
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• 2007

Most of current building materials are made of organic compounds or at least made with chemical treatments. Though easy to use and comparatively pay less, those materials are generally not enviornmentally sound. VOC is one of harmful effects. On contrary, natural materials such as soil are usually eco-friendly, and environmentally sustainable as well if not treated in autoclaves. Acoustica materials made of such environmentally sound and sustainable could be widely used. It is aimed to prove that soil based materials could be effectively used in acoustical fields rather than the other usual materials. Experiments with various types of soil blocks and soil plaster were performed. It is proved that the soil plaster has better apsorption features than cement plaster. Soil blocks have higher absorption cofficients than soil plaster, due to the thickness, and the absorption characteristics can be controlled by the design of the blocks.

• Elastomers and Composites
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• v.46 no.1
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• pp.10-21
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• 2011

Recently, with developments in the automotive industry, sound and vibration damping have a considerable attraction with a diversified customer needs and advanced automobile. In general, among various materials, textile materials, such as felt and glass fibers, polyurethane foam, and PET fiber materials were used to reduce sound and vibration of the automobile. These materials were located in various main parts of the automobile to block sound and vibration, resulting in a comfortable ride. In addition, to improve fuel economy, weight reduction and cost saving for the automobile were also being considered together as well as the reduction of sound and vibration of the automobile. Therefore, in this paper, we focused on the need of interior sound and vibration absorption materials in the automobile and absorption materials-related technologies.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.25-34
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• 2012

The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of alternative methods to solve the social requirements of noise problems. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block for quiet pavement. The specimens, which is fixed hall-size, space, depth as the condition of this research, are analysed of noise reduction effect using different noise levels of vehicles. Judging from the analysis of test results with vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base and quiet asphalt surface showed a good alternative solution for decreasing traffic noise level, from 4dB to 9dB.

• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.223-231
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• 2018

Recently, due to various environmental problems, blast tracks in tunnel are replaced with concrete tracks, but they have more adverse effects on noise than blast tracks so that additional noise measures are needed. Among these measures, sound-absorbing blocks start to be used due to its easy and quick installation. However, the performance of sound absorption blocks need to be verified under real environmental and operational conditions. In this paper, interior noise levels in KTX train cruising in Dalseong tunnel are measured before and after the installation of sound-absorbing blocks and the measured data are analyzed and compared. Additionally, noise reduction are estimated by modeling the high speed train, the tunnel and absorption blocks. Measurement devices and methods are used according to ISO 3381 and the equivalent sound pressure levels during the cruising time inside the tunnel are computed. In addition to overall SPLs(Sound Pressure Levels), 1/3-octave-band levels are also analyzed to account for the frequency characteristics of sound absorption and equipment noise in a cabin. In addition, to consider the effects of train cruising speeds and environmental conditions on the measurements, the measured data are corrected by using those measured during the train-passing through the tunnels located before and behind the Dalseong tunnel. Analysis of measured results showed that the maximum noise reduction of 6.8 dB (A) can be achieved for the local region where the sound-absorbing blocks are installed. Finally, through the comparison of predicted 1/3-octave band SPLs for the KTX interior noise with the measurements, the understanding of noise reduction mechanism due to sound-absorbing blocks is enhanced.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.35-42
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• 2010

The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of considerable method to solve the social requirements of noise problem. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block. There are specimens which is fixed hall-size, space, depth as the condition of this research, and these are analysed of noise decrease effect using different condition of the first noise of each vehicle. As a result of analysis data according to vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base showed a good alternative solution for decreasing traffic noise level, from 4 dB to 9 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.195-200
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• 1994

과학문명의 발달은 지구환경에 미치는 영향이 서로 달라도 환경파괴라는 대가를 치르면서 발전하여 왔다. 환경문제는 수질오염, 대기오염, 폐기물 및 소음진동이 있다. 이중에서 소음진동과 관련된 환경문제는 도시가 커지고 기계문명이 발달하면서 심각성은 더해가고 있다. 환경소음중 주거생활에 직접적으로 영향을 미치는 교통소음, 공장소음에 대하여 일반적인 성분을 파악하였다. 조사시 소음레벨보다는 주파수 분석에 의한 특성을 중시하였으며, 주파수 분석 결과에 따라 저주파 대역 및 고주파 대역으로 분류하였다. 음향블럭은 시멘트 블럭을 가공하여 제작한 것으로 일정한 크기의 홈이 있다. 음향블럭의 음향특성은 이 홈에 따라 달라지는 것이 일반적인 특성인데 본 연구에서는 동일한 음향블럭에 대하여 설치방법 및 흡음재 사용에 따라 달라지는 음향 특성에 대하여 실험결과와 적용방법을 제시하였다.