Superhydrophobic and Anti-Icing Coatings on Asphalt Pavements: A Review

Ice formation on asphalt roads poses severe safety hazards and maintenance issues, especially in cold climates. Traditional deicing methods are typically energy intensive, environmentally adversive, and economically inadvisable. Alternative superhydrophobic coatings (SHCs) have emerged as promising passive anti-icing solutions. This review summarizes recent trends in the development of SHCs for asphalt applications, focusing on three generic categories: carbon nanotube (CNT)-based, silica (SiO₂)-based, and silicone-based systems. Their surface chemistry, preparation techniques, adhesion to asphalt substrates, and icephobic performance parameterssuch as water contact angle, ice adhesion strength, and more importantly, freezing delay timeare noted by the review. Freezing time measurements, which quantify the ice formation delay on coated surfaces under controlled low-temperature conditions, are referred to as a pivotal measure of SHC efficacy. Although there is promising laboratory data, there are issues regarding coating durability, scalability for application on a large scale, environmental concern, and standardization of tests. The review finishes by looking forward to research directions necessary to bridge the gap between laboratory evidence and practical implementation.