Contribution of an asphalt pavement modified with TiO2 to the moderation of the Urban Heat Island (UHI)

Urban pavements, covering up to 40% of cities, intensify the Urban Heat Island (UHI) phenomenon by impeding rainwater infiltration and absorbing solar radiation. High pavement temperatures increase urban energy demand and pollution. One important factor affecting pavement temperature is albedo. The higher the albedo, the less solar irradiation the pavement absorbs, and the cooler it remains. This study evaluates TiO2 incorporated into asphalt to enhance albedo. The thermal response of conventional and TiO2-modified pavements was monitored under natural sunlight. Opto-thermal properties were measured initially and after twelve months of outdoor exposure. An energy balance quantified the heat amount released to the environment for both pavements. Results demonstrate TiO2 effectiveness in reducing heat storage and improving radiative cooling over time. Additionally, the mechanical and rheological impacts of TiO2 on asphalt binders were analyzed. Cool pavements with TiO2 emerge as a viable UHI mitigation strategy, offering energy savings and enhanced urban sustainability.