Noise-Reducing Pavements for Highways and Urban Roads -State of the Art in Denmark

摘要

Noise is one of the most serious environmental problems caused by road traffic. About 28% of all Danish homes are exposed to more than 55 dB, which is the official recommended noise limit for road traffic noise. The Danish government has a long-term goal to reduce the noise to a level that is considered satisfactory for the health. According to the national road noise strategy, one of the most cost-effective means of noise abatement is the use of noise-reducing pavements. In this paper, the on-going Danish research to develop and test different types of noise-reducing pavements is presented and discussed. Single-layer porous pavements with a high built-in air void and a small maximum aggregate size have been tested on a highway with a speed-limit of 80 km/h. Over the structural lifetime, the noise reduction of the porous pavements was 3-4 dB relative to dense asphalt concrete with a maximum aggregate size of 12 mm. In order to achieve the same noise reduction, the traffic volume must be reduced by more than 50%. On an urban test road with a speed-limit of 50 km/h, similar single-layer porous pavements have been tested. Here, the observed noise reduction of 3 dB disappeared within 2 years, because the pores of the pavement were clogged. Three new types of two-layer porous asphalt are now being tested on an urban road with a speed limit of 50 km/h. These pavements are designed and constructed to avoid clogging and to improve durability. The pavements are cleaned with special equipment using water under high pressure twice a year. After four years, noise reductions of approximately 3 dB have been measured compared to a dense asphalt concrete with a maximum aggregate size of 8 mm. In order to develop new types of cost-effective noise-reducing pavements for urban application, research and testing of different kinds of thin surface layers have been started in the framework of an EU research project (SILVIA).