Study on the solar-thermal effect mechanism and energy balance relationship of heat-reflective pavement model in cold region

Against the backdrop of global warming and accelerated urbanization, the proliferation of dark asphalt pavements has exacerbated urban heat island effects and highway damage in cold regions. Heat-reflective pavement, a promising cooling pavement technology, has yet to be systematically studied in terms of experimental models, solar-thermal mechanisms, and energy balance. Relevant studies are still relatively scarce in typical cold regions. This paper attempts to address this gap by conducting experimental and theoretical analyses of heat-reflective pavements in typical cold regions. The findings reveal significant seasonal and climatic variations in the solar-thermal characteristics of these pavements. Heat-reflective pavements notably reduce the maximum, annual average, and amplitude of temperature and heat flux in asphalt surfaces, as well as the N-factor variation. Increasing pavement albedo from 0.05 to 0.78 results in a reduction of the annual average temperature and heat flux by approximately 4 °C and 12 W/m². Furthermore, heat-reflective coatings significantly modify the energy balance of pavement surface, including the magnitudes, patterns, and proportions of heat exchanges. A new simple method for determining the upper thermal boundary conditions of heat-reflective pavements is proposed. The research results provide data accumulation and theoretical support for mitigating urban heat island effects and improving the thermal stability of permafrost embankments.