Pervious asphalt pavement- and concrete wall-watering for urban cooling: Characterization of surface cooling effects at an outdoor test site

Abstract

Pervious pavement- and wall-watering was studied at a 100 m2 pilot site in Hy'eres (France). Surface temperature monitoring was conducted continuously with an infrared camera to assess watering's cooling effects and duration as well surface drying time for the concrete fa¸cade and the pervious pavement. Watering was conducted every hour for 15 min from 8 am to 6 pm in summer 2021. Results show up to 14.3 °C surface temperature reductions for pervious pavementwatering, and up to 8.4 °C of cooling for wall-watering applied to a South-facing wall. For shaded surfaces, maximum cooling is limited to 5 °C, whether vertical or horizontal. Between watering cycles, the vertical and impervious wall surface dries in approximately 15 to 20 min. For the pervious pavement, drying time varies along the surface. While certain areas, downstream, don't dry between watering cycles, others dry in 25 to 35 min. These variations depend on the relative height of the considered zone along the pavement slope, as well as the pavement's material and topographical irregularities. Residual cooling effects are observed the following night until the next morning for both pavement- and wall-watering, in the order of 3.5 °C and 1 °C at 6 am, respectively. Results further illustrate the higher efficiency of urban watering solutions for surfaces in direct sunlight.