A poroelastic road surface is a wearing course made essentially of rubber granules bound together with a binder and with a selection of particle sizes resulting in a porous structure. This report describes attempts to construct and test in laboratory and field experiments three poroelastic surfaces intended for road traffic noise reduction in urban areas. The studied surfaces were made up of rubber particles bound with polyurethane to create a 30 mm thick porous structure with 30-35 % interconnecting air voids. 

Laboratory experiments indicated very low wear of the test specimens due to exposure to studded tyres as well as very low emissions of particles in the air. They also indicated rolling resistance to be comparable to that of a conventional asphalt surface. Adhesion to the base course and skid resistance received particular attention and the laboratory experiments indicated satisfactory performance. Three types of poroelastic road surfaces were laid in 2004 on one lane of a street in Stockholm City carrying a mix of light and heavy traffic (5400 AADT, 50 km/h posted speed). Wet skid resistance measurements and dry braking tests indicated satisfactory performance. Noise measurements with the CPX method indicated tyre/road noise reductions relative to the adjacent asphalt surface of 10-15 dB(A).

After a few months, the experiment was interrupted due to the underlying asphalt surface separating from the asphalt layer beneath it. This was very unfortunate since the rubber surfaces and the adhesion of them onto the first asphalt layer still seemed to perform well. The report includes comprehensive descriptions of the testing, production and maintenance of the tested poroelastic surfaces. An exception is the results in terms of wet friction and noise measured in the Stockholm street experiment, since this is the subject of another report and therefore not treated here. Furthermore, this report includes comprehensive conclusions and recommendations for further work.