Sound absorption characteristics of rubberised porous asphalt mixture

Traffic noise pollution has increased the demand for low-noise pavements. Improving the sound absorption performance of asphalt mixtures is crucial for reducing tyre-pavement noise. This study investigates the sound absorption characteristics of rubberised porous asphalt mixtures (RPAM) at macro- and micro-scales, focusing on the effect of rubber particles. The results indicated that there was a significant correlation between the maximum aggregate size, rubber particle content and the sound absorption performance of RPAM. Furthermore, the pore characteristics of RPAM with different maximum aggregate sizes and rubber particle contents were extracted by X-ray CT scanning and 3D reconstruction techniques, and the impact on sound absorption performance was investigated. The grey correlation analysis showed that pore characteristic parameters including throat length and coordination number had a more significant impact on the sound absorption performance. Reducing the maximum aggregate size and rubber particle content can increase these parameters, thereby improving the sound absorption performance.