Anti-Icing Properties of a Polyurethane Superhydrophobic Coating on Asphalt Pavement

Snow and ice accumulation on asphalt pavement can increase the risk of traffic issues. The traditional method of removing snow and ice manually or mechanically from the road surface is time-consuming and labor-intensive. Another common method of spraying salt pollutes the surrounding environment. To overcome these issues, the objective of this study is to study a polyurethane superhydrophobic coating on asphalt pavement and characterize its anti-icing and road properties. A polyurethane superhydrophobic coating (PSC) using polyurethane and carbon nanotube particles (CNTPs) was developed in the lab. The contact angle and roll angle tests, surface roughness test, water droplet icing test, differential scanning calorimetry (DSC) test, ice adhesion test, pavement skid resistance test, water permeability test, and load wheel rolling test were conducted. The results show that the static contact angle and the rolling angle of the water droplet on the PSC surface are 161.176° and 6.6°, which satisfy the requirements to be superhydrophobic. The icing time of the water droplet on the asphalt mixture coated with PSC (AMC) is twice that of the surface of the ordinary asphalt mixture (OAM). In the differential scanning calorimetry test, the PSC released heat slower than polyurethane and asphalt binder during the cooling process. The ice adhesion strength of AMC is 82.78% smaller than that of the OAM. This means the PSC has great anti-icing and deicing properties. In addition, the pendulum value on the AMC surface is 45.7, satisfying the pavement skid resistance requirement. The results of the water seepage test show that the AMC is impermeable to water, thus reducing the risk of water damage to the pavement. Finally, the contact angle of the AMC after the indoor load wheel rolling is still greater than 150°, which proves that the PSC has good wear resistance. In summary, the PSC has good anti-icing properties and road performance.