Road traffic noise barriers based on recycled materials.

Abstract

One of the main corrective measures taken to reduce environmental noise produced by roads is using sound barriers. However, the construction of miles of noise barriers implies a high cost. One solution to reduce the costs is using recycled materials in the noise barriers, for example, plastic wastes, which has great environmental benefits. According to EN 1793-1 to 3:1998, the main acoustic characteristics of noise barriers are the sound absorption and the airborne sound insulation. On the other hand, the technical document CEN/TS 1793-5:2003 gives guidelines for determining the in situ sound reflection index, which is an important parameter because the reflections from the barrier may increase the background noise in the surrounding area. This method has not been validated for noise barriers having a relatively low airborne sound insulation. In this study, sound reflection index using the impulse method is obtained in the laboratory for a wide frequency range. Environmental designs of road traffic noise barriers based on recycled materials with minimum sound reflection index are obtained. Optimization of the acoustic characteristics of the designs allows one to reduce the annoyance in the vicinity of the noise barrier.