Book Description
Highway traffic noise is a major environmental issue all over the world. This is particularly annoying to residents who live nearby major transportation corridors. Noise pollution adversely affects the quality of their life. It also causes sleep disturbance and anxiety. The most commonly used noise abatement technique is the use of noise barrier walls, which is costly and not always effective. Reducing the tirepavement noise at the source is a viable alternative to cut down the noise level. This study examined the use of an impedance tube to measure the acoustic absorption of asphalt mixtures in the laboratory. The effect of various parameters on the acoustic absorption was investigated including aggregate gradation, aggregate type, binder type, percent air voids, and specimen thickness. In addition, factors that could affect the acoustical performance of asphalt mixtures after pavement construction were also investigated including air void structure, surface texture, temperature, and surface conditions. Percent air voids and layer thickness were found to have a significant influence on the acoustic absorption of asphalt mixtures. An analytical model was proposed to estimate the acoustic absorption coefficient of asphalt mixtures during the design stage. A good correlation was found between predicted and measured absorption coefficients in the laboratory. In addition, a double-layer system of asphalt mixtures was found to be effective in providing improved acoustical performance that overcomes the issues associated with the use of open-graded friction course as a wearing surface.
