Development of low noise and durable semi-dense asphalt mixtures

Abstract

The application of low noise pavement is one of the most effective solutions to reduce tire/pavement noise. Low noise pavements are achieved by using asphalt mixtures with a high air void content (e.g. porous asphalt). However, these material have relatively low durability. Therefore, to ensure sufficient durability and long-term acoustic properties, low noise asphalt mixtures must be designed considering both acoustic and climatic conditions. The main objective of this study was to design four semi-dense asphalt mixtures (2 stone and mastic asphalt (SMA) mixtures and 2 asphalt mixtures for very thin layers (BBTM)) with increased air void contents (>10%) that absorb tire/pavement noise and are resistant to traffic and climate conditions. Large-scale laboratory testing was performed to evaluate the acoustic properties as well as the effects of traffic and climate conditions on the performance of the designed asphalt mixtures. These tests revealed that modified BBTM asphalt mixtures have better sound absorption properties than modified SMA mixtures but are less resistant to rutting, have lower stiffness and indirect tensile strengths and exhibit higher mass loss after freeze-thaw cycles. BBTM 5 which has the highest air void content (15.4%), had the highest (0.54) sound absorption coefficient of all the tested mixtures. The most promising asphalt mixture was identified by a developed analytic hierarchy (AHP). The BBTM 8 mixture is the most rational solution for low noise pavement.