Snow and Ice Melting Performance Evaluation and Economic-Environmental Assessment of a Novel Steel Slag-Based Composite Phase Change Aggregate Asphalt Pavement

The traditional mechanical equipment/chemical salt approach for pavement snow/ice removal is costly and may cause serious environmental pollution problems. To facilitate the pavement snow/ice melting in a more economical and sustainable way, a novel steel slag-based composite phase change aggregate (SS-CPCA) asphalt pavement was developed, and its technical performance was experimentally evaluated. The experimental results revealed that: (1) after 14 cycles of freeze-thaw treatment, the SS-CPCA asphalt pavement has an identical temperature regulation performance as its initial state, identifying that its long-term thermal durability is promising; (2) snow layer with a thickness of 5 mm that is covered on the SS-CPCA asphalt pavement at 0°C can be melted completely within 32 min, verifying that the SS-CPCA asphalt pavement has a satisfactory snow melting performance; and (3) a decrease of environmental temperature can result in an increase of ice melting rate (IMR) and a decrease of effective ice melting time (EIMT), indicating that the IMR and EIMT should be balanced to each other when selecting appropriate PCMs for pavement snow/ice melting. In addition, the economic-environmental performance of the SS-CPCA asphalt pavement was examined through a case study. It was found that, as compared with conventional asphalt pavements, it has a relatively higher initial construction cost. However, when taking the snow/ice removal cost into account, its total cost is significantly lower for the second-year application. Further, the SS-CPCA asphalt pavement can dramatically reduce CO2 emissions as compared with the traditional snow/ice melting approaches. Thus, it can be concluded that the newly developed SS-CPCA asphalt pavement can provide considerable economic-environmental benefits toward the pavement's snow/ice melting.