Environmentally Friendly Pavements: final report

Abstract

This final report presents the main results, advice and recommendations from the research and development program Environmentally Friendly Pavements run by the Norwegian Public Roads Administration (NPRA) in the period 2004-2009. The main focus of the project has been to optimise the environmental properties of road surfaces with respect to low road tyre noise and road dust emissions. The project has shown that: The tested environmentally friendly pavements give an initial noise reduction of 3-9 dB(A) compared to the reference level (SMA11 older than one year). The noise reducing effect decreases relatively rapidly for all types of pavements that have been investigated. Annual increase in noise levels measured on Norwegian pavements is considerably higher than what is reported from a number of other countries. The increase is particularly large during the first winter. It is natural to explain this phenomenon by the wear from studded tires and its influence on the pavement surface texture. The friction properties of tested environmentally friendly pavements are in the same range as traditional Norwegian pavements, and they require no special winter maintenance. Porous pavements seem to have slightly better friction than dense pavements with similar maximum aggregate size. It is difficult to develop pavements with considerably higher wear resistance than those we have today, without compromising other important properties as stability and friction. However, through adjusted requirements for material quality and mix design, it is possible to maintain the durability of low noise pavement alternatives.