Characterization of self-cleaning pavement coatings with catalytic-hydrophobic synergistic effects

Abstract

The deterioration of the atmosphere around the road and the decrease in the cleanliness of the road surface due to fuel vehicle exhaust emissions, spilled transport goods, and vehicle wear deposition not only affect the experience of road users, but also threaten the health of the surrounding residents. Pavement coatings with self-cleaning functions can purify the atmosphere around the road and improve the cleanliness of the pavement. To provide raw material support for self-cleaning pavement coatings, hydrophobically modified TiO2 was prepared by Polytetrafluoroethylene (PTFE) coating method and epoxy resin modified silicone resin was prepared by the co-blending method. The optimal preparation scheme was selected to develop self-cleaning pavement coatings with catalytic-hydrophobic synergistic effects (SCPC). The exhaust gas degradation and hydrophobically cleaning performance of permeable asphalt mixture specimens with different SCPC spraying volumes were tested using self-developed evaluation methods. The experimental results show that modification of TiO2 with PTFE of 1.2 times its mass significantly increases the contact angle with little loss of photocatalytic performance. Under the best process and proportion, the epoxy resin and silicone resin are blended uniformly, and the mechanical properties can meet the demand of road use. The exhaust degradation and hydrophobically cleaning efficiency of SCPC are satisfactory when the spraying volume is greater than 500 g/m2. Moreover, the increase in spraying volume enhanced the hydrophobic cleaning ability. In addition, the SEM images show that the surface of SCPC presents a micron-level rough structure, which is conducive to enhancing the hydrophobic self-cleaning of SPSC. The permeability will inevitably be affected after SPSC is sprayed on the surface of permeable asphalt mixture, but when the spraying volume is less than 800 g/cm2, the attenuation rate of the permeability coefficient of the specimen is within 10%. The exhaust degradation and hydrophobic properties of the permeable asphalt mixture specimens with reasonable amounts of SPSC were tested after wear, and the attenuation was found to be very slight, indicating that the environmental performance of SPSC has good wear resistance.