Comprehensive Laboratory Evaluation of Thermophysical Properties of Pavement Materials: Effects on Urban Heat Island

In the context of urban heat islands (UHI), sustainable solutions are being devised to craft greener built environments such as cooler roofs and pavements mainly to counter a variation of thermal flux within the urban climates. Modification of the pavement thermal properties is a potential strategy to render pavements cooler with different cooling mechanisms. The thermal behavior of pavements is largely dependent on the different but interactive thermal properties of pavement materials such as thermal conductivity, specific heat capacity, density, albedo, thermal emissivity, and not on one single property alone. The objective of this research study was to investigate the thermophysical properties of different pavement systems through the development of a comprehensive methodology that can quantify contribution of thermal properties on urban climates from laboratory-based measurements. Six different paving mixtures including conventional dense-graded, asphalt-rubber, and cement concrete mixes were prepared encompassing 96 sample data points for the experimental program. With an increase in specific heat capacity, thermal conductivity, thermal diffusivity, and albedo, there was a decrease in the maximum pavement surface temperature of the various mixes. Although the investigation of thermal behavior of pavement materials is complex in nature, this laboratory study has attempted to investigate all major thermophysical properties of different pavement systems in a comprehensive manner. It is envisioned that this research study will help advance the state of the art and knowledge related to pavements' selection and contribution to urban climates, and in recommending a suitable UHI mitigation strategy from the pavements' perspective.