Preparation and microwave heating performance of a sustainable de-icing asphalt coating by introducing reversible disulfide bonds

In cold regions, road surface icing poses a significant threat to traffic safety, leading to increased accident rates and considerable socioeconomic losses. Commonly used de-icing strategies include mechanical removal and salt spreading. Mechanical methods require substantial investment in equipment and maintenance, while salt-based approaches may have negative environmental impacts. In this study, a microwave-responsive, self-healing asphalt coating (SPMA) was developed by blending self-healing polyurethane (SP) with hydroxyl-functionalized multi-walled carbon nanotubes (MWCNT-OH) at a mass ratio of 30:1, and incorporating the composite into matrix asphalt. Under microwave irradiation, SPMA with 5 wt% SP/MWCNT composite exhibited a maximum surface temperature of 57.0 °C after 300 s, with an average temperature of 55.2 °C, indicating improved microwave heating efficiency and reduced thermal gradients. The de-icing rate of SPMA remained consistently high throughout the microwave heating test, outperforming both matrix asphalt and MWCNT-blended matrix asphalt (MA) specimens. After knife scratching, surface scratch on the specimens were nearly fully repaired within 20 h at 25 °C, indicating reliable self-healing performance due to reversible disulfide bonds. After 500 rutting abrasion cycles, the SPMA maintained both thermal responsiveness and structural integrity. The durability and skid resistance properties have been further substantiated through the 100 cycles of vehicular loading. These results suggest that SPMA holds promise for long-term de-icing applications on cold-region pavement.