Evaluation on Solar Heat Reflective Coatings to Reduce Asphalt Concrete Temperature

Abstract

As the development of civil construction, the heat island effect in large cities of China has gradually become a social issue. Pavements, especially asphalt pavements, are considered to be one of the main causes of the heat island effect as they cover wide area of cities. In some regions, the surface of asphalt pavements can even be heated up to more than 70°C by solar irradiation in summer times due to the excellent heat-absorbing property of asphalt concrete. In this paper, a solar heat reflective coating on asphalt pavement was investigated to reduce asphalt pavements temperature and mitigate the heat island effect. A solar heat reflective coating was synthesized with certain component contents of resin, pigments, fillings and additives on the basis of the principles of heat reflection. The surface temperatures of the concrete covered by solar heat reflective coating and the reference were compared. Meanwhile, an accelerated loading test with loaded vehicles was performed for these two asphalt concretes. The influence of the reduction in the surface temperature on the air temperature was simulated. The research results indicate that the solar heat reflective coating can obviously reduce the surface temperature of asphalt concrete for its high light-reflection rate in the infrared and visible wavelength region. Furthermore, the accelerated loading test also suggests that this coating improves the rutting resistance of the asphalt concrete compared to the reference when exposed to the same irradiation strength. Therefore, this solar heat reflective coating on asphalt pavement could be adopted as a countermeasure against the heat island effect.

Development of Super Road Heat-Reflective Coating and Its Field Application

“…The functional filler comprises TiO 2 and SiO 2 . High reflectivity guarantees the cooling effect of heat-reflective coatings; the higher the coating reflectivity, the better its cooling effect [21,39,40]. Therefore, in this study, the functional filler content was optimized based on the resulting cooling effect.…”

“…Cao et al compared the internal temperature of asphalt and heat-reflective pavements; At 2.5 cm depth, the temperature of the traditional pavement reached 62.7 • C, while that of the heat-reflective one was reduced by 9 • C [12]. Outdoor tests and experiments on test sections have also been conducted to further confirm the cooling effect of heat-reflective coatings [7,10,20,21]. Furthermore, Jiang et al reported that heat-reflective pavements have better stability at high temperatures [17,22,23].…”