In Situ Characterization of a Full Scale Poroelastic Test Section in Belgium

During the European PERSUADE project, a full scale test section with a poroelastic road surface (PERS) has been built on a road with regular traffic in Herzele in Belgium. The acoustical performance of the PERS test section has been monitored during ten months. SPB, CPB and CPX measurements were performed and showed no significant deterioration of the acoustical properties over time. The noise reduction was remarkable. Noise reductions up to 9 dBA were measured in comparison with and old asphalt concrete at the reference speed of 50 km/h. Several road properties influencing rolling noise have also been measured in situ. Mean Profil Depth (MPD) and road texture spectra were assessed from texture measurements with a dynamic laser profilometer. Sound absorption was measured following ISO13472-1 and appeared to be relatively low for a porous road surface. Mechanical impedance of the road surface was also measured using a specific impact method. Thus, the dynamic Young modulus of the road surface was estimated using a single degree of freedom approach. The stiffness was relatively high for a PERS but much less than a traditional asphalt concrete, having a good potential for reduction of tyre/road interaction via the elasticity of the road surface.