The effects of pavement surface characteristics on tire/pavement noise
Introduction
Tire/pavement noise is a major source of traffic noise at high speeds. The noise exposure not only impairs human hearing capacity (hearing loss), but also causes some mental diseases [1]. Sound wall or sound barrier is a common measure to mitigate traffic noises, but their construction and maintenance costs are high.
Originally, Porous Asphalt (PA) and Open-Graded Friction Course (OGFC) were developed in Europe and US to improve frictional resistance of asphalt pavements [2]. The spray and splash were significantly reduced and surprisingly noise levels were also mitigated. It was believed that pavement surface characteristics (such as porosity, texture, and stiffness) might be major attributes to tire/pavement interaction and they might lead to cost-effective options to mitigate traffic noises. Since then, poro-elastic material and asphalt rubber material are also reported to reduce noise levels [3], [4], [5].
With regard to the effects of pavement surface characteristics on noise levels, previous researches show that macrotexture and International Roughness Index (IRI) increase noise levels at lower frequencies and higher air-void content reduces noise levels at higher frequencies [6], [7], [8]. However, until now, the question about the relative significance of pavement surface characteristics on noise levels is still not well known [6]. This paper will help to understand tire/pavement noise generation mechanisms and to design new generation of low-noise asphalt pavements.
Section snippets
2009 NCAT test track
Forty-six asphalt pavement sections are included in the 2009 NCAT oval-shaped test track (Fig. 1), 40 of them are impervious asphalt pavements (including 27 fine-graded Superpaves, eight coarse-graded Superpaves [9], five Stone Mastic Asphalt (SMAs)), and the other ones (six sections) are open-graded asphalt pavements (OGFCs). Among them, 10 fine-graded and eight coarse-graded Superpave pavement sections (all constructed in 2009 except for E4 section in 2000), five SMA and five OGFC pavement
Single surface characteristic analysis
Like those done in many previous researches, the linear regression analysis method is used to evaluate the effects of single pavement characteristic on noise levels.
Multiple surface characteristic analyses
The effects of single pavement surface characteristic have been evaluated in Section 3. A more important and interesting question may arise among many researchers that which pavement surface characteristic is the paramount important contributor to noise levels at different frequencies. The answer to this question will not only help to understand tire/pavement noise generation mechanisms and also benefit to design the future low-noise pavement surfaces.
Impervious asphalt pavement
From Sections 3 Single surface characteristic analysis, 4 Multiple surface characteristic analyses, it shows that surface texture of impervious asphalt pavements increase noise levels at lower frequencies (below 1600 Hz, especially at 500 Hz). So, if you want to reduce noise levels efficiently, you should decrease Mean Profile Depth (MPD) of surface texture as far as possible. But this may sacrifice driving safety on these pavements because friction between a tire and a pavement may decrease as
Conclusions
The effects of single and multiple pavement surface characteristics on noise levels are evaluated in this paper based on the data collected from 2009 NCAT test track. The following conclusions can be drawn.
- (1)
Pavement surface texture (MPD) increases noise levels below 1600 Hz especially on impervious asphalt pavements.
- (2)
Pavement surface porosity (VA) decreases noise levels at every frequency (except at 2500 Hz) on open-graded asphalt pavements.
- (3)
Pavement surface stiffness (E*), roughness (IRI) and
Acknowledgements
The authors gratefully appreciate the support from Dr. Buzz Powell at NCAT at Auburn University and the fund from China Scholarship Council (CSC).
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