The development of novel cool asphalt pavement structures to alleviate the urban heat island effects

Abstract

The urban temperature is usually higher than the suburban temperature due to some human activities and inventions, one of which is asphalt pavement. Asphalt pavement absorbs and stores solar energy during the day and releases it at night, exacerbating a phenomenon named urban heat island (UHI). Two different solutions were proposed in this research to mitigate the effects of UHI. Firstly, the asphalt pavement was coated with chip seals made of some recycled materials to increase the surface reflectivity and reduce heat absorption during the day, cooling the asphalt pavement. The mechanical properties, safety, and durability of these new chip seals were also evaluated for cold and hot weather conditions. Although the heat entering the asphalt pavement can be minimized by reflective pavements, it cannot be zero. Hence, the absorbed heat in the asphalt mixture should be transferred into the layers below to observe a smaller thermal gradient between the asphalt mixture and its surrounding air. As a result, less heat is transferred to the ambient air, mitigating the UHI. For this purpose, the second proposed solution was enhancing the heat transfer at the interface of the asphalt mixture and base course and developing a conductive base course. Therefore, an industrial by-product, steel slag, was utilized to prepare a conductive prime coat and a conductive base course. Overall, the laboratory and field experiments indicated that reducing pavement heat absorption and transferring the absorbed heat into the base course can decrease the asphalt pavement temperature, resulting in less heat release into the ambient air and mitigating the UHI associated with asphalt pavements.

Date	6 Feb 2026
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Michel Vaillancourt (Supervisor) & Alan Carter (Co-supervisor)