Overview
Currently noise counts as one of the most significant sources of environmental pollution. Today, many people suffer from the burden of noisy traffic, the continuous growth of which is causing a steady increase in noise levels.
These are objectives of the project:
- Periodically measuring of noise levels on different test sections, having regard to already existing ones and the corresponding data.
- By means of measurements in labour and field to find correlation between specific properties of the surfaces and the noise level of different surfaces (considering the available national and international experiences).
- It is planned to take into consideration in each case the specific safety recommendations. The goal is to deduce new rudiments and guidelines, which enables an optimised design of pavements with regard to surface noise. Objectives
- Noise measurement with IVT-trailer and testing the dynamic properties of pavements
- Optimisation of pavement properties with regard to noise emission.
Finally the research shows how to improve the pavement structure or how to consider it by design.
Funding
Results
On November 5, 1992, the Swiss Federal Highways Office ordered the IVT - ETH Zurich to investigate rolling noise emissions (and related factors) from a variety of road surfaces. The goal was: to investigate the potential of keeping motor and rolling noise emissions (from both tyre and surface) at their current levels, or even reduce them, despite rising traffic.
Between 1985 and 1999 around 4000 noise measurements were taken on approximately 500 stretches of road with about 20 different surfaces, in order to determine A-weighted sound levels as well as tertiary band spectra. The measurements resulted in surfaces being subdivided into four groups.
The first group includes surfaces with "low to medium" sound levels with a maximum tertiary band level of 1.6 kHz. AB 11, AB 16, TA 10, TA 16, MR 11, SMA 11 and SMA 16 surfaces all belong to this group. AB 16 surfaces, and those consisting of composite mixture S, are somewhat noisier. AB 11 shows the best results in this group.
The second group includes the noisy surfaces of concrete, GA, HRA 16 and HRA 25 with maximum tertiary band levels mostly at 1 kHz.
The third group includes porous asphalts, whose noise emissions depend to a high degree on their age. With hollow spaces intact, they belong to the low noise group; with blocked hollow spaces, to noisy ones. Seal coats (0B) are also part of this group, showing similar dB (A) levels and tertiary band spectra as drain surfaces with blocked hollow spaces. The maximum tertiary band level is about 1 kHz.
The fourth group includes SMA 6, SMA 8, micro surfaces and seal coat 3/6. SMA 6 clearly shows lower sound levels. The maximum tertiary band level is around 1.6 kHz, an advantageous point bearing in mind noise control measures.
The fourth group includes SMA 6, SMA 8, micro surfaces and seal coat 3/6. SMA 6 clearly shows lower sound levels. The maximum tertiary band level is around 1.6 kHz, an advantageous point bearing in mind noise control measures.
In addition, the relationship between sound emissions and other key factors was investigated, the most important proving to be surface temperature. With a difference of 50° C, noise levels change by 4 dB (A) for drain asphalts, about 3 dB (A) for compact bituminous surfaces, and about 2 dB (A) for concrete and seal coats.
The role texture plays was more difficult to determine. Qualitatively, tertiary band analyses of a surface are the same for all velocities and, in general, the maximum sound level does n