Evaluation on Solar Heat Reflective Coatings to Reduce Asphalt Concrete Temperature

摘要

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.