Durability of the noise-reduction performance of the PMSMA and CRSMA pavements - a case study in Hong Kong

Abstract

Tyre/road interaction noise is one of the main sources of urban traffic noise, which has aroused public concern about health and living environment. Low-noise road surface (LNRS) is a feasible solution to reduce tyre/road noise from its source. As a high-density city, Hong Kong has studied the noise-reduction performance of different LNRS materials in the past decade, such as the crumbed rubber modified stone mastic asphalt (CRSMA) and polymer modified stone mastic asphalt (PMSMA) with a small maximum aggregate size. This study aims to evaluate and compare the durabilities of the noise-reduction performance of CRSMA and PMSMA pavements. The close-proximity (CPX) method was applied to collect the tyre/road noise data over three consecutive years after the pavements were constructed. The sound pressure levels and spectrograms were investigated to compare the noise reduction durabilities of the two LNRS materials. The results showed that the CRSMA6 pavement showed good and relatively stable noise reduction performance during the whole observation period. In contrast, although PMSMA6 presented a lower noise level than CRSMA6 at the early stage, its noise reduction property gradually deteriorated. PMSMA6's noise value surpassed CRSMA6 in the third year.