Phosphorescent-based pavements for counteracting urban overheating – A proof of concept

The built environment is particularly sensitive to elevated temperatures across urban areas. Furthermore, engineered materials usually amplify surface overheating, exacerbating urban heat island and cooling energy needs. In the last decades, the scientific community introduced a new class of materials, i.e. cool materials, in the attempt of mitigating these phenomena. In this context, this work investigates the hygrothermal and radiative potential of phosphorescent-based paving solutions and benchmarks their performance against commercially available cool concrete. To this end, an extensive outdoor monitoring campaign was carried out in terms of surface/air temperature, relative humidity, reflected solar radiation and wind speed/direction during summer 2019. Phosphorescent-based fields were found to maintain lower superficial temperature than the reference during the hottest hours of the day, by up to 0.9 °C and 3.3 °C in terms of average and absolute values, respectively. Even though other cooling techniques have been found to have higher cooling effect, the outcomes of this study, reveal for a first time, (i) the promising thermal behavior of phosphorescent-based pavements, as well as (ii) their potential for developing advanced cool materials equipped with both radiation reflection and re-emission mechanisms.