Noise performance of drainage asphalt pavement

In this paper, the noise-reducing characteristics of open graded drainage asphalt mixture pavement were investigated. Based on the prevailing theory of the Pumping Effect between tire and pavement, tire-pavement noise was evaluated. The Standing Wave Tube (SWT) method and the Roadside Pass-by (RPB) method were used. The acoustic properties of the five types of asphalt mixtures typically used in the Beijing region were determined. Properties studied in the laboratory included the noise reduction coefficient and sound absorption coefficient. In situ noise levels and noise frequency spectrums were obtained and compared using these methods. Also, the relationships between the noise reducing coefficient and the percentage of air voids (Va), nominal maximum aggregate size (NMAS), and texture depth (TD) were also analyzed. Analysis of the frequency spectrum of the pavement noise indicated that the open graded drainage asphalt pavement mixture had outstanding performance in reducing the noise level compared with that of dense-grade mixtures. Its noise reducing coefficient was twice as large, and it reduced the pavement equivalent continuous sound level (Leq) by 3.4 to 6.7dB(A).