Cooling Effect of Permeable Asphalt Pavement under Dry and Wet Conditions

Abstract

The improvement of the street thermal environment for walking and cycling is attracting increased attention as a strategy for increasing livability. This approach has also been proposed as a strategy for mitigating the local heat island effect and reducing energy use for buildings and vehicle air conditioning during hot periods. This research explored a potential pavement design and management strategy for improving the street thermal environment and mitigating the heat island effect. Through field measurements on pavement test sections with both conventional and alternative designs, the thermal behavior and cooling effect of permeable asphalt pavements under dry and wet conditions were investigated. The overall 7-day average cooling effect of wetting once on permeable pavements for near-surface air was approximately 0.2°C to 0.45°C; for the surface, the temperature was approximately 1.2°C to 1.6°C, and it was approximately 1.5°C to 3.4°C for the in-depth layers. On the basis of these findings, permeable asphalt pavements might be a type of cool pavement that produces lower temperatures and thus helps improve the thermal environment and mitigate the heat island effect. However, attention should be given to this type of pavement under dry conditions. As a pavement thermal management strategy, water from rain or irrigation systems might need to be applied to the pavements to produce a better cooling effect for improving the thermal environment and mitigating the heat island effect.