Thermosetting powder coating for asphalt pavement

The high temperature in asphalt pavement during summer accelerates the rutting and aggravates the phenomenon of urban heat island (UHI). One of the mitigation methods is the use of heat-reflective coating (HRC) on asphalt pavement. However, conventional HRC faces some challenges such as poor abrasion resistance, poor skid resistance and environment pollution. In this paper, a new type of coating, named thermosetting powder coating (TPC), was developed for reflecting heat off asphalt pavement. Four types of TPCs, including the polyester powder coating (PPC), modified polyester powder coating (MPPC), polyester/epoxy powder coating (PEPC) and modified polyester/epoxy powder coating (MPEPC) were made. Meanwhile, A type of conventional HRC was chosen as a reference. Performances tests were conducted to evaluate the cooling effect, skid resistance, abrasion resistance, adhesion strength, anti-glare performance and erosion resistance of the asphalt concrete specimens coated by the TPCs or conventional HRC. Impacts on performances of several factors such as resin type, application rate and texture agent were discussed. Finally, the costs of the TPC and conventional HRC were compared. Results indicate that though the cooling effect and anti-glare performances of these two types of coatings are resembled, the skid resistance, abrasion resistance and adhesion strength of the TPC are better than those of conventional HRC. What's more, the cost of the former is only 0.1 times of that of the latter. Among four types of TPCs, MPPC is recommended to be used for reflecting heat and its optimum application rate (dosage) is 100–150 g/m2.