Development and performance of sand fog seal with cooling and air purification effects

Two types of environment-friendly SFS (sand fog seals) with cooling and air purification effects are developed to achieve environmental effects under the condition of good road performance. In this work, the cooling and air purification effects at different temperature ranges are studied using a thermal-insulation device and air purification testing equipment developed independently by our research group. Meanwhile, the pavement performances are confirmed using artificial laying sand instrument, pendulum instrument and pavement seepage meter. Finally, the microstructures are analyzed using the scanning electronic microscopy and fourier transform infrared spectroscopy. The cooling and purifying mechanisms are discussed based on relevant chemical theory. Results show that the optimum spraying amount of environment-friendly SFS materials is 0.75 kg/m2, the highest cooling effect can reach more than 5 °C, and the purification rates of carbon oxides, nitrogen oxides, and sulfur dioxides can reach more than 16%. In addition, the purification rates of particulate matters with particle size below 2.5 (PM2.5) and below 10 µm (PM10) are about 20%. Results also reveal that these two types of environment-friendly SFS have good road performances, and the functional modifier distributes evenly and stably in fog seal materials. The self-polarization effect of the functional modifier likewise contributes to the cooling and air purification effects.