Noise reducing thin pavements - urban roads

Thin pavements optimised for noise reduction are being developed as a promising tool for noise abatement.The Danish Road Institute (DRI) and Road and Hydraulic Engineering Institute in the Netherlands (DWW) are coop-erating on the DRI-DWW noise abatement programme.A test section with six types of thin layers including a reference pavement was established on a Danish highway in 2004.The purpose of this experiment is to document the noise reducing effect, and on the long term the acoustical and the structural lifetime.Noise measurements were performed according to the international standard ISO 11819-1 characterizing road surface influence on traffic noise the so called SPB method when the pavements were a few months old and one year old.Furthermore, a series of CPX measurements were performed in year 0.To describe the surface texture detailed texture measurements has been performed by laser equipment.The friction has also been measured.The noise increased 0 to 1 dB from year 0 to 1. At the reference pavement there was no increase.Relative to the reference there was a noise reduction for the thin layers of 1 to 3 dB in both years.The tendency was a slightly lower noise reduction in year 1.The uncertainty for the SPB measurements was 0.4 dB.