On site acoustical characterization of a removable urban pavement with functionalized surface

Removable urban pavement consists in an assembly of cement concrete slabs that can be easily removed or replaced for maintenance purposes. Within the I-STREET CUD-SF project, a removable urban pavement with functionalized surface was implemented in the inner city of Nantes in France. The slabs are made of cement concrete with a dense body and a porous top layer of grading 0/6 and porosity 25%, enabling water drainage and sound absorption. The demonstrator was approximately 31 m long by 6 m wide. Road surface texture was measured in 3D, leading to classical texture indicators and assessment of irregularities at the junction between slabs. Sound absorption was also measured by the extended surface method. Noise performance of the pavement was assessed at 30 km/h by the Statistical Pass-By and the Close-Proximity methods. Pass-by noise level was reduced by 2.3 dBA by comparison with the old pavement. Close-Proximity noise levels have shown a reduction of 3.4 dBA by comparison with an old DAC 0/10. The noise abatement is mainly due to a decrease in the frequency range between 800 Hz and 1600 Hz. Noise measurements will be repeated after one year to highlight a possible evolution of acoustical performance.