Which pavement structures are best suited to limiting the UHI effect? A laboratory-scale study of Parisian pavement structures

Paving materials can negatively impact the urban climate, but knowledge of the thermal and climatic behavior of multilayer urban structures is lacking, particularly under heat-wave conditions. To this aim, a laboratory-scale experiment was developed to characterize pavement samples under heat-wave conditions. Surface albedo and evapotranspiration are confirmed as the dominant parameters for surface heating. The thermal properties of the underlying layers of pavement structures also impact their behavior and contribution to the urban climate. In particular, the combination of high effusivity and diffusivity of the granite sidewalk structure allow it to exhibit cool behavior during the day and hot behavior at night despite its relatively high albedo. A solar transmission index is proposed, including both the radiative and the thermal properties of a structure's constitutive layers, to rank structures by their ability to transmit absorbed radiation in depth. Future work with the developed experimental platform will aim to evaluate the performance and optimize the watering method of pavement-watering for different kinds of pavement structures.