This study explores the extent to which porous asphalt pavement influences pavement temperatures and investigates the impact on UHI by considering the diurnal temperature cycle. A one-dimensional pavement temperature model developed at Arizona State University was used to model surface temperatures of porous asphalt, dense graded asphalt and Portland cement concrete pavements. Several scenarios were considered to include variations in pavement thickness, structure and albedo. In addition, thermal conductivity testing was performed on porous asphalt mixtures to obtain values for current and future analysis. In general, porous asphalt exhibited higher daytime surface temperatures of the three pavement types because of the reduced thermal energy transfer from the surface to subsurface layers. In comparison, porous asphalt showed the lowest nighttime temperatures when compared to other materials with similar or higher albedo. This trend can be attributed to the unique insulating properties of this material along with a high air void content. As anticipated, the outcome of this study indicated that pavements impact on UHI is a complex problem and needs to consider important interaction between influencing factors such as pavement thickness, structure, material type, and albedo.
Source: 2012 Annual Meeting of the Transportation 39 Research Board
Publication Date: July 2011