Acoustic and economic analysis of the use of palm tree pruning waste in noise barriers to mitigate the environmental impact of motorways

Abstract

This research has a twofold environmental benefit. On the one hand, there is the recycling of a waste by-product and, on the other hand, the reduction of traffic noise pollution levels. The objective of this study is to determine and evaluate the use of a mixture of shredded palm tree pruning waste with dampened topsoil in the construction of noise barriers. With a view to efficiently recycling pruning waste and using an environmentally-friendly material which does not pose any environmental risks at the end of its useful life, the composition offering the best sound absorption has been analyzed. Based on the results obtained, a completely eco-friendly roadside noise barrier (RNB) 1:1 scale model was built, and noise levels measured at various points close to it. Significant sound absorption benefits were detected, not only in the shaded area behind the barrier, but also in the unprotected area immediately above the barrier. Furthermore, the economic feasibility of both the construction and recycling processes has been calculated.