Heat-reflective technology for cold-region roads: Mechanisms, materials, performance and life-cycle perspectives

Heat-reflective technologies reduce solar heat gains of asphalt surfaces and can contribute to energy-efficient, low-carbon transport systems. Their relevance is amplified for cold-region highways, where disturbed surface energy exchange can accelerate permafrost warming and intensify freeze-thaw distress. However, the evidence base remains dispersed and often fails to connect optical engineering with roadway performance and life-cycle implications. This review synthesizes laboratory measurements, outdoor-model experiments, and field monitoring through a surface-energy-balance framework, covering coating and material systems, spectral-property characterization, cooling effectiveness, functional performance, and life-cycle assessment considerations. Reported datasets consistently indicate that increasing albedo yields a monotonic, often near-linear, reduction in surface temperature and radiation indices, with measurable cooling in shallow pavement layers. Among deployable options, coating-based solutions dominate current practice, particularly multilayer epoxy or acrylic matrices formulated with near-infrared selective pigments. Evidence underscores the roles of binder chemistry and surface texturing in resisting aging. Their benefits are strongly modulated by embankment slope and aspect, which govern short-wave radiation. Functional outcomes show systematic trade-offs: lower operating temperature can improve rutting resistance and moisture sealing, whereas skid resistance, adhesion, and optical retention depend on surface texture, freeze-thaw exposure, snowplowing abrasion, and de-icing chemicals. Based on these insights, we propose a cold-region evaluation framework and research priorities including standardized spectral sensing, predictive optical-aging models, coupled thermo-mechanical simulation, AI-enabled field assessment or material design, and context-specific life-cycle accounting. As this technology matures and its adoption scales, it is expected to enhance the whole-life service performance of cold-region road transport infrastructure while reducing life-cycle costs.