Measurement of road surface sound absorption coefficients by use of impulsive sound

摘要

The development of an in-situ instrumentation system to measure the sound absorption coefficient of the road surface is strongly desired for the purpose of the maintenance of the drainage pavements. This paper describes the structure and the performance of the developed system. In the system, a loudspeaker radiates an impulsive sound and a microphone picks up the incident sound and the reflected sound. As the height of the system has big influence on the performance, the effects of the height are mainly investigated. According to the results, the microphone height should be higher than 60cm. If the height is lower, there can be a considerable error due to the slight change in the microphone height.