Comparison of Surface Characteristics and Pavement/Tire Noise of Various Thin Asphalt Overlays

Recently, the use of pavement surfaces designed to reduce traffic noise has become a common practice. Reducing noise levels by proper selection of surface type is considered a more effective strategy compared to sound walls since the noise is treated at the source. Before placing more open graded mixes, there is a need to identify their noise reduction properties, durability, and safety, and to compare these with other asphaltic mixes. In 2005, California Department of Transportation initiated a long-term program to investigate and monitor field performance of different open graded mixes and other commonly used asphalt surface mixes. This paper summarizes part of the first-year measurements of relevant parameters from asphalt pavements with different surface mixes. It was found that open graded mixes generally reduce the tire/pavement noise level, and the amount of reduction is correlated with air-void content, and surface texture. However, the noise-reduction benefit may be lost with the increase of pavement ages.