Road traffic is the pre-dominant source of noise affliction in Norway. Construction of noise barriers and facade insulation of buildings are the most commonly used measures for traffic noise reduction but were found to be insufficient to meet the national target. It therefore became necessary to look for ways of reducing noise at source.
The high concentration of suspended matter (dust) due to the use of studded tyres is a significant problem in several Norwegian cities, particularly on dry winter days, and the poor air quality represents a threat to public health. As a result, standards have been set for the maximum acceptable dust concentration, and these are expected to be strengthened in 2010. Thus it has become necessary to develop environmentally friendly pavements which will help in alleviating noise and dust pollution.
The project focuses on optimising the environmental properties of road surfaces in order to reduce the environmental impact on surroundings, and thereby contribute to achieving the environmental targets set for levels of dust in suspension and noise.
Further work will ensure that the environmental improvements proposed are at an acceptable cost and do not cause significant problems in other areas.
The project includes the following work areas:
- Strategy development
- Operation and maintenance
- Trial pavements
- Functional requirements
- Impact analysis (on the economy, safety, health and the environment)
- Special pavements.
The 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.
Optimisation of the environmental properties of road surfaces in order to reduce the environmental impact on surroundings.
Enhancing using of the environmentally friendly pavements on roads.