Cement-fly ash-based anti-icing concrete coating material for application onto tunnel-lining surfaces in cold regions

Large icing areas on the tunnel-lining surface can affect safe operation of roads and railways in cold regions. However, traditional deicing technologies (i.e., thermal and manual deicing) have problems, such as high-energy consumption, high cost, and low-deicing efficiency. To effectively solve the problem of “easy freezing and slow deicing”, we prepared an anti-icing concrete coating material using cement and fly ash, which exhibits cost-effectiveness and high anti-icing efficiency. The high performance of the coating material mainly relied on the developed low-cost and high-efficiency emulsion-type hydrophobic admixture and the micro-/nanobinary rough structure resulting from the recycled nylon mesh and metakaolin nanoparticles. Based on the systematic surface properties and freeze–thaw (F-T) and ice adhesion tests, we found that this material exhibited satisfactory anti-icing ability, easy deicing performance, and remarkable F-T durability. In addition, the superhydrophobicity mechanism and easy deicing property were studied via X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Finally, we established a novel contact angle (CA) model considering the micro-/nano binary structure of the concrete surface and a theoretical model of ice adhesion. Based on this, the influence of surface CA and ice adhesion was theoretically analyzed. This research provides important guidance for solving the anti-icing problem of the tunnel-lining surface in cold regions and can realize the transition from “passive deicing” to “active anti-icing”.