This Communication describes and discusses the results of laboratory and practical research carried out to assess the applications of porous asphalt surfacings. The research was carried out with the two thickness versions of the material, i.e. 20 and 40 cm. The tests have shown that the porous asphalt course has clear advantages with respect to road safety and environment. Thanks to the high percentage of hollow space the material has large water storage and drainage capacities. This considerably reduces the risk of aquaplaning, whereas in rainy weather also the splash and spray water is reduced. Moreover, the porous asphalt course is highly resistant to deformation. From the environmental point of view it is an asset that the noise produced in the contact between tires and road surface is (significantly) less than with other friction courses. Until recently there was uncertainty as to a number of aspects of porous asphalt application, one of these aspects being the contribution to the constructive strength of the road surfacing. Now this strength is assumed to be 75% of that of non-porous courses of similar thickness. Also the aspect of winter maintenance seemed to pose problems, but it has been experienced meanwhile that this is negligible provided a proper set of de-icing measures is applied; moreover, problems of this type will only apply under exceptional wintery conditions. Considering all aspects, it is the opinion of the working group that the time has come for a large-scale application of the porous asphalt surfacings though it is desired to study the stretches already realized of considerable length to quantify the positive effects and to work out a number of remaining questions. (Author/publisher)
Samenvatting