Tyre/road noise reduction of poroelastic road surface tested in a laboratory

A so-called poroelastic road surface (PERS) is being developed in Europe. This contains a large percentage of rubber particles mixed with hard aggregate (stone and sand) and bound with polyurethane. This gives high air void content (around 30 %), high elasticity and smooth texture, all of which should give low noise properties. Inthis experiment anominally 30 mm thick sample of PERS was mounted on a steel drum. Various car tyres were then run on the PERS surface at a range of speeds, while measuring noise levels and frequency spectra. Similar measurements were made when the drum was equipped with a replica of a dense as phalt surface as well as a rough-textured surface dressing. These measurements indicated a 9-10 dB reduction in A-weighted noise level compared to the replica of the dense asphalt surface, and even higher when compared to the surface dressing. In addition, rolling resistance measurements were made with similar equipment and facility. The results showed that the rolling resistance was almost as low as that on a smooth sandpaper surface (a standard surface allowed in ISO tests), which is likely to give lower rolling resistance than most conventional road surfaces.