Suggested Citation:
Xie, Ning, Hui Li, Ahmed Abdelhady, John T. Harvey (2019) Experimental Study of the Optical and Thermal Properties of Reflective Coatings for Pavement. Transportation Research Board 98th Annual Meeting

Urban heat island (UHI) effect causes the increasing demand of energy consumption for building and environment cooling. As a type of cool pavement technology, a reflective coating can effectively counterbalance the urban warming effect. However, the investigation of the optical properties and their relation to colored reflective pavement coatings at the full solar spectrum (200 nm-2500 nm) of solar radiation is still in its infancy. This paper prepared ten non-white coating samples to evaluate the optical properties and thermal performance of pigments and coatings. It was found that color is a dominant factor of reflectance in the visible radiation region; however, it does not affect the near-infrared radiation reflectance. The coatings doped in chrome achieved reflectance around 60% and the near-infrared reflectance was similar to the white coating, around 95%. The relation between lightness and visible reflectance was linear for coatings in dark and medium color [brightness index (L*) 80]. Based on the statistical analysis, the reflectance in visible radiation region and short wave near-infrared radiation region (400 nm to 1100 nm) were the dominant factors to influence thermal performance of coatings. A simple proposed model (linear trend) between reflectance and surface temperature of the reflective cool pavement coatings has been investigated. The investigated results could provide insights and references for optimizing the design of reflective cool pavement coating and developing the metameric matching colored coatings without glare and aesthetic problems to mitigate the urban heat island effect.

Key words: Color, nanostructured materials, optical properties, pavements, thermal properties