Influence of mixture design parameters on tyre–pavement interaction noise of polyurethane porous elastic road surfaces (PUPERS)

Polyurethane porous elastic road surfaces (PUPERS) are promising low-noise pavements owing to their excellent acoustic performance and cold-mix construction advantages; however, how mixture design parameters govern their tire-pavement interaction noise (TPIN) reduction mechanisms remains insufficiently understood. In this study, twelve PUPERS mixtures were prepared by varying aggregate particle size, rubber particle size, rubber content, and porosity. Their sound absorption, vibration energy attenuation, and surface texture were characterized using impedance tube testing, vibration attenuation testing, and three-dimensional laser texture scanning, while TPIN was measured by the tire vertical drop method. Sound absorption is strongly affected by the ratio of aggregate particle size to rubber particle size and by rubber content, with apparent trend changes around a particle size ratio of 2.5 and a rubber content of 20 wt.%, whereas higher porosity consistently enhances absorption. All mixtures outperform AC10 and PA10 in vibration attenuation and achieve a maximum TPIN reduction of 9.9 dB(A). Spectral analysis shows that TPIN reduction mainly suppresses tire structural vibration within the 500-1600 Hz band through the combined effects of enhanced vibration attenuation and reduced macro-texture, while the porous structure provides additional noise reduction above 2000 Hz. These findings guide the mixture design of low-noise pavements.