Spectral noise reduction of double-layer porous asphalt: From laboratory to field

• Published in: Construction & building materials 2024-09, Vol.445, p.138025, Article 138025
• Main Authors: Liao, Gongyun, Zha, Jiaji, Lu, Xueyuan, Wu, Wei, Zhang, Weijie, Wang, Hao, Zhang, Zhenshan, Liu, Xiaodong
• Format: Article
• Language: English
• Subjects: Double-layer porous asphalt; Interior noise; Noise reduction; Sound absorption; Spectral noise; Surface condition
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2024.138025

The double-layer porous asphalt (DLPA) pavement is a practical way to mitigate traffic noise from the source. However, there hasn't been much research done on the spectral noise characteristics of the car/truck on this type of pavement with different surface conditions yet. The objective of this paper was to reveal these noise characteristics and the behaviors of the DLPA pavement by laboratory tests and field measurements. First, measurements were made of the road performance of different porous asphalt (PA) mixtures and DLPA structures. Then, a vector impedance measurement system was utilized to evaluate the effects of porosity, aggregate size, and thickness on the sound absorption coefficient (SAC) of the DLPA slabs. Third, a sound meter was used to record the noise levels outside/inside the car/truck on the roads with three surface conditions for the DLPA (PA-10+PA-20) and stone matrix asphalt (SMA) test section, which were paved on an elevated urban road. Finally, an analysis was done on the overall and spectral noise characteristics. The results demonstrated good road performance of these PA mixtures and DLPA structures. Relatively fine and coarse aggregates in the upper and lower layers, respectively, enhanced the sound absorption. But an increase in porosity beyond 20 % and a slight variation in thickness did not considerably improve the sound absorption. Compared to SMA pavement, the overall noises levels of the DLPA pavement were 4–8 dBA lower on the “dry” surface and 6 dBA lower on the “wet” surface. The DLPA pavement exhibited a noise reduction at the full frequency band, which attributed to the pore structure and the relatively fine aggregate used. The interior sound energy always concentrated on the low-frequency band. However, the exterior sound energy on the “dry” and “wet” road surfaces tended to the low-frequency and high-frequency bands, respectively. These findings would shed light on the spectral noise characteristics of the DLPA pavement and provide a new knowledge about the behaviors of the lower layer and upper layer in relation to noise reduction and road performance. [Display omitted] •The PA-10+PA-20 structure was measured in the laboratory and test section.•The effects of porosity, aggregate size and thickness were evaluated.•Both the overall and spectral noises were measured and analyzed.•Both the exterior and interior noises were measured and analyzed.•The noises on three road surface conditions were measured and analyzed.