본 연구의 목적은 복층 배수성·저소음 아스팔트 포장의 공용수명 예측과 경제성 분석에 있다. 성능평가를 위한 현장시 험은 투수시험 및 소음 측정을 실시하였으며, 실내시험은 반사균열, 동탄성계수, 소성변형(FN) 시험을 진행하였다. 성능 평가 결과를 기반으로 포장설계 수명 예측 및 비용 편익 분석을 수행하였으며, 이를 일반 밀입도 포장의 비용 편익과 비 교·분석하여 복층 배수성·저소음 아스팔트 포장의 경제성을 확인하고자 하였다. 성능평가 결과 복층 배수성·저소음 포장 이 일반 밀입도 포장과 비교 시 소음 저감 성능에서 매우 우수한 결과를 나타내었다. 비용 편익 분석 결과 복층 배수성· 저소음 아스팔트 포장은 높은 초기비용에도 불구하고 설계기간동안 낮은 유지보수 비용을 가지며 안전 및 소음 측면에 서 일반 밀입도 포장과 비교 시 매우 경제적인 것으로 나타났다. 총 비용과 총 편익 비용을 편익 비용 비율(BCR)로 계 산한 결과 복층 배수성·저소음 아스팔트 포장이 단위 비용 당 편익 측면에서 방음벽이 있는 다른 포장에 비해 가장 우수 한 결과를 보였다.

This study aimed to evaluate the performance criteria of low-noise asphalt pavements under laboratory conditions. Laboratory tests were performed on eight porous and three non-porous asphalt mixtures. Draindown, Cantabro, tensile strength ratio (TSR), and dynamic stability tests were conducted to evaluate durability. The functionality was assessed using sound-absorption and indoorpermeability- coefficient tests. The laboratory results showed that all mixtures satisfied the quality standards for the draindown and TSR tests. In the dynamic stability test, all the mixtures demonstrated adequate rutting resistance. For porous mixtures, the Cantabro test results indicated sufficient shatter resistance and the indoor-permeability-coefficient test confirmed proper drainage performance. All mixtures exhibited satisfactory sound absorption, with the porous mixtures exhibiting slightly better sound absorption than the non-porous mixtures. Both porous and non-porous mixtures are durable and functional and are used in Korea. Future field tests are required to evaluate the noise reduction performance under different conditions and to compare the in-situ performance results with those from laboratory tests.

도로 포장 기술이 발달함에 따라 내구성 확보 등의 구조성능 중심에서 이용자의 승차감 및 소음 저감 등의 기능성 중심으로 변화하 고 있다. 최근 도로 소음에 대한 민원이 증가하고 있고 도로 소음으로 인한 피해를 보상하라는 판결 사례도 증가하고 있다. 이러한 문 제를 해결하기 위해 차량 소음 저감 효과가 우수한 저소음 포장을 적용하고 있다. 본 연구에서는 저소음 배수성 포장과 저소음 비배 수성 포장의 내구성 및 공용성을 평가하였으며, 기대수명 예측을 위해 국내에 있는 배수성 8종, 비배수성 3종의 제품을 이용하여 실내 성능 평가를 수행하였다. 국토교통부의 "아스팔트 콘크리트 포장 시공 지침(2021)"의 배수성 포장 품질기준 및 비배수성 혼합물에 대 한 품질기준에 따라 시험을 진행하였다. 아스팔트 혼합물의 생산, 저장, 운반 및 포설 시 아스팔트의 흘러내리는 양이 적합한지를 평 가하기 위해 드레인다운 시험을 진행하였고, 배수성 혼합물의 골재 비산 저항성을 평가하기 위해 칸타브로 손실률 시험을 진행하였다. 또한 포장의 수분 저항성을 평가하기 위해 인장강도비(TSR) 시험과 소성변형 저항성을 평가하기 위해 동적안정도 시험을 진행하였다. 이후, 배수성 포장의 투수 성능을 평가하기 위한 실내투수계수 시험을 진행하였고, 저소음 포장의 소음 저감 성능을 평가하기 위해 임 피던스 관을 이용한 흡음률 시험을 진행하였다. 시험 결과 모든 종류의 혼합물이 품질기준을 통과하여 충분한 기초 성능을 가지고 있 는 것으로 나타났고, 흡음률 시험의 경우 배수성 혼합물이 평균 0.779, 비배수성 혼합물이 평균 0.638의 흡음계수를 나타내었다. 배수 성 혼합물과 비배수성 혼합물의 평균 공극률은 각각 19.3%, 3.2%로 배수성 혼합물이 비배수성 혼합물에 비해 많은 공극률을 가지고 있어 소음 저감 성능이 비배수성에 비해 우수한 것으로 판단하였다.

PURPOSES : The purpose of this study is to estimate the reduction in traffic noise in a double-layered specific porous pavement at roadsides based on variations in traffic volume and driving speed. METHODS : A statistical pass-by (SPB) method was employed in this study to measure noise. Variations in the following parameters were measured: running speed, heavy traffic percentage, and traffic volume. RESULTS : Quantitative analysis revealed that the double-layered porous pavement reduced noise levels by 9.16 dB(A) at a 95% confidence level at the sides of roads. CONCLUSIONS : As a countermeasure of traffic noise, porous pavement has been recommended. This research quantitatively proved that double-layered porous pavement can reduce traffic noise by more than 9.0 dB(A) at roadsides

PartI of this paper identified the location and size of the noise sources from the axial flow fans, and partII based on that, identified the magnitude of sound pressure from the case and the blade according to frequency in the range of 2200 Hz to 5000 Hz. The equation of Lighthill was used for calculation. Generally, when measuring noise, the analytical area was extended more than 1m from the outlet of the fan. To eliminate the effects of backflow coming from the rear of the fan, the analytical area was extended a little longer than 1m. From the results of the analysis, high noise occurs in the low frequency area, and the lower noise becomes in the high frequency area. The maximum sound pressure generated in the range of 2000Hz~5000Hz is 65dB at a distance of 1m and 82dB at the outlet of the fan. Noise of the fan mainly occurred around the blade and guide, and the noise decreased as the frequency increased between 2200Hz and 3400Hz, but the noise increased as the frequency increased between 3800Hz and 5000Hz.

In this study, numerical analysis was carried out to develop low-noise axial fans, which are often used for ventilation in houses. A commercial program and the turbulence models are used for the analysis of internal fan. Proudman acoustic power model and the Curle surface acoustic power model were used for analysis. As a result, the distribution of flow velocity and pressure around the blade and guide of the fan was high, and low in the center of the fan. Noise from the inner wall of the fan case and the blade surface was the highest at the body and vane connections of the blade, and low at the center of the vane and the center of the body.

PURPOSES : The purpose of this study is to estimate the reduction of traffic noise in a double-layered specific porous pavement based on the traffic speed variation. METHODS : The close-proximity method was used in noise measurement, and the running speed was measured at 10 km/h and from 50 to 80 km/h. RESULTS : From the quantitative analysis, it was found that the double-layered porous pavement reduced by 9.4 dB (A) on the average and 9.16 dB (A) at a 95% confidence level. CONCLUSIONS : The use of porous pavements have been recommended to minimize traffic noise. In this study, it is quantitatively demonstrated that the double-layered porous pavement can reduce the traffic noise by more than 9.0 dB(A).

PURPOSES : In many European countries, the fine-size exposed aggregate concrete pavement (EACP) technique has been adopted for a quiet pavement. However, different noise reduction levels were reported based on the mixture design and texture conditions. This study aims to suggest a quality control condition for achieving low-noise texture and a mixture design procedure for exposed aggregate concrete overlay (EACO), which will provide the optimum mixture of the surface texture that can reduce the tire-pavement noise. METHODS : The tire-pavement noise is highly influenced by the pavement surface texture. The surface texture of the EACP can be quantified by the mean texture depth (MTD) and the exposed aggregate number (EAN). The optimum condition for the low-noise texture of the EACP was investigated herein based on the analysis of the review of the texture conditions and noise measurement in many EACP sites. RESULTS : The MTD and EAN criteria can be derived according to the investigated relationship between noise and texture condition. The optimum mixture design to satisfy these criteria can be achieved by controlling the maximum size of the coarse aggregate and the S/a. CONCLUSIONS: This study aimed to suggest a quality control condition for achieving low-noise texture and an optimum mixture design for EACO. As a result, we found that the early traffic opening of EACO can be achieved by using high early-strength cement.

In advanced countries, various policies are being enforced to reduce equipment noise level at it’s source. This paper analyses the problems of domestic noise policies related to noisy equipment, and presents a plan for improving the implementation of expansion policy of low noise equipment based on this analysis. This paper proposes that the equipment satisfying the compulsory rule be able to use the environmental certification mark, the standards of which are defined in recommended rules, to improve the linkage between the two policy measures. This paper also suggests expanding the range of equipment to be supervised and using new noise label that has grades and shows detailed noise level of the equipment to improve environmental certification system. In addition, supplementing the construction permission system and supporting international certification system are offered to expand the use of low noise equipment.

PURPOSES : The purpose of this study is to compare noise reduction quantities between before/after two-layer low noise pavement implementation using equivalent noise level analysis and to analyze the noise reduction effects of the two layer low noise pavement with a statistical method such as the Anderson-Darling Test.METHODS: In order to compare and to analyze noise reduction effects between before/after two-layer low noise pavement implementation, data acquisition as noise levels on a roadside and an apartment rooftop was conducted in the study area. The equivalent noise level was estimated in order to compare noise reduction quantities and the Anderson-Darling Test was carried out for estimating noise reduction effects of the two-layer low noise pavement.RESULTS: The equivalent noise levels of before/after two-layer low noise pavement implementation for the roadside during the daytime are 65.355 dB and 63.520 dB and during the nighttime are 62.463 dB and 59.088 dB. The equivalent noise levels for the apartment rooftop during daytime are 57.301 dB and 59.088 dB and during the nighttime are 54.616 dB and 52.464 dB. Also two-layer low noise pavement decreased the noise reduction effects estimated with the statistical method as the Anderson-Darling test for the roadside during the daytime by around 66.68% and decreased noise reduction effects on the roadside during the nighttime by 0.70%. Moreover it reduced noise reduction effects in the apartment rooftop during the daytime and nighttime by 0% and 96.32%, respectively.CONCLUSIONS : Based on the result of this study, two-layer low noise pavement can positively affect noise reduction during both the daytime and nighttime according to the results of estimating the equivalent noise levels and the Anderson-Darling test.

최근 서울 도심 지역에 급격한 자동차 수 증가로 인한 도로교통소음의 심각성이 사회에서 주목을 받고 있다. 각 기관들은 도로교통소음을 해결하기 위해 여러 가지 방안을 내놓고 있으며, 2017년 3월 서울시는 저소음포장을 소음감소대책으로 내놓았다. 여러 가지 소음감소대책 중 저소음포장이 최근 들어 많은 관심을 받고 있는 이유는 방음벽과 방음터널의 경우 도심의 미관을 파괴하고 소음대책이 필요한 지점에 따라 소음저감 효과가 상이하게 발생하는 반면, 저소음포장의 경우 소음대책이 필요한 지점에 상관없이 일정한 소음저감 효과를 나타내고 있기 때문이다. 이와 관련하여 본 연구에서는 소음예측 프로그램을 통하여 저소음포장의 소음감소효과를 평가를 하는 것을 목적을 두고 있다. 소음예측은 Korea Environment Institute 가이드라인에 기초하여 수행되었다. 저소음 포장에 대한 감소효과를 평가하기 위해 소음지도 모델링을 진행하여야 한다. 모델링의 경우 일반포장에서의 실제 교통량과 통행속도를 입력하여 나온 시뮬레이션 값과 실제 지점에서 소음을 측정한 값이 3dB차이가 나지 않아야 검증된 모델로 규정하고 있다. 이렇게 검증이 된 모델을 사용하여 소음예측을 진행하였을 때, 일반 포장이 설치 된 도로를 저소음포장으로 교체 설치하여 소음감소도를 분석하게 된다. 또한 저소음포장이 한 층 및 두 층으로 포장되었을 경우에 대해 소음감소도를 분석하였고, 여러 조건의 속도와 교통량을 입력하여 각 조건별로 감소도를 분석하였다. 여러 가지 상황에서 어떤 경우에 가장 많은 감소도를 보이는지 분석하였다. 그림 1.은 특정 교통량과 특정 속도에 대한 소음예측을 한 것이다. 그림 2.의 경우는 그림 1.과 같은 교통량과 속력을 입력하였지만 포장이 저소음포장을 두 층으로 바꿔 설치 된 것이다. 그림을 비교해보면 저소음포장을 설치한 경우 7dB의 감소도를 볼 수 있다. 이를 포함한 많은 경우의 수에서 저소음포장에 대한 소음감소도를 분석하였다

PURPOSES : In this study, noise reduction effect of a two-layer porous asphalt pavement was investigated through site measurement and computer simulation. METHODS: To examine noise reduction effect, a 3 km long quiet pavement was installed by removing previous normal pavement, which had a rather low porosity. The studied site was a high-rise apartment building surrounded by the quiet pavement and Seoul ring road with heavy traffic volume, indicating relatively high background noise. RESULTS: The measurement result before and after installing the quiet pavement showed a noise reduction effect of 4.3 dB(A) at a distance of 7.5 m from the road. After validating the accuracy of simulation using SoundPLAN, the reduction in SPL(sound pressure level) at the facades by the quiet pavement was predicted by considering five different road conditions generating traffic noise from each road or in the combination of the quiet pavement and Seoul ring road. In the case of no noise from Seoul ring road, noise reduction at the facades was 4.2 dB(A) on average for 702 housing units. With background noise from Seoul ring road, however, the average SPL decreased to 2.0 dB(A). Regarding subjective response of noise, the number of housing units with a noise reduction of over 3 dB(A) was 229 out of 706 units (approximately 32%). For 77 housing units, the noise reduction was between 1~3 dB(A), while it was less than 1 dB(A) for 400 housing units. CONCLUSIONS: The overall result indicates that the quiet pavement is useful to reduce noise evenly at low and high floors compared to noise barriers, especially in the urban situation where background noise is low.

PURPOSES: The purpose of this study is to evaluate the effect of the quiet pavement on reducing a barrier height by using a prediction tool called SoundPLAN. METHODS: Firstly, the prediction was carried out to evaluate the difference in the maximum noise level at a building facade between the normal and the quiet pavements without a barrier. After calculating the noise reduction effect by the quiet pavement, a comparable barrier height to obtain the same noise reduction effect with it was predicted according to designable factors including road-building distance(10 m, 20 m, 40 m) and road-barrier distance(5 m, 10 m, 20 m, 30 m). RESULTS: The result showed that within the considered designable factors, the maximum barrier height was 37 m, 52 m, and 55 m to have the same noise reduction effect by the quiet pavement reducing 1 dBA, 3 dBA , and 5 dBA, respectively. It was evaluated that the barrier height increased with the increase of the road-building and road-barrier distances. To simulate the real situation in urban areas and to evaluate the combined effect of the normal/quiet pavement and barrier, the barrier height was fixed as 6 m. It was predicted that the noise level would reduce to as low as 0.2 dBA by the combination of normal pavement and barrier. On the other hand, the combination of the quiet pavement and barrier reduced 1.2 dBA, 3.2 dBA, and 5.2 dBA, respectively, for quiet pavement reducing 1 dBA, 3 dBA, and 5 dBA. CONCLUSIONS: A guideline needs to be suggested to select appropriate noise abatement schemes by considering factors such as the roadbuilding and road-barrier distances.

도로에 인접한 아파트 주동을 대상으로 일반 도로포장 대비 저소음 도로포장의 소음저감효과를 예측한 후, 일반 도로포장 시 이에 상응하는 소음레벨 저감을 위한 방음벽 높이를 예측하여 저소음 도로포장의 경제성 분석을 위한 기초연구를 수행하였다. 5dBA의 소음저감효과를 나타내는 저소음 도로포장 설치조 건에 대한 예측결과 최대 54m의 방음벽 높이를 저감시킬 수 있는 것으로 예측되어 도시미관 및 경제성 측면에서 효과적인 것으로 분석되었다.

The noise from the exhaust system to the engine is important in terms of the problem of noise pollution, as well as improved marketability, there are many studies being made. Normally, the exhaust noise change is the exhaust manifold of the muffler or four days depending on the structure of the portion of the shape and the Lancer, called look a big difference, and the perforated pipe resonance, expression that contains a study of the structure of the muffler is a general precedent. This muffler is based on four wheel to differentiate between the borrower and the borrower can be broken down into a motorcycle. The details of the stock muffler, the muffler is tuned racing use. Therefore, this study is the last motorcycle noise and exhaust emission for environmental tests have not been established yet 125cc motor cycle noise is used as a reference for the criteria for information about the experiment. There are few types of motorcycle muffler, such as stock muffler, slip on muffler and full system muffler used racing. On this study through to the measurement motorcycle exhaust noise and analysis 1/3 octave band get a target frequency. For the design resonance muffler used Helemholtz’s resonance formular. Also when design the muffler consider mount of frame. This studied expect reduction noise without sound absorption.