Energy-Efficient Tunnel Paving Materials Based on Road Surface Luminance

To address the issue of excessive energy consumption in tunnel lighting, this study investigates the use of energy-efficient tunnel paving materials based on road surface luminance observed by drivers, which is applied by the reflection characteristics of the road surface. Using scaled model experiments and DIAlux lighting simulations, the luminance performance of nine types of pavement materials and three types of sidewall materials was systematically evaluated. The results show that sidewall materials primarily enhance lateral visual comfort and contribute minimally to improving pavement luminance. Even with high reflectance sidewalls at a reflectance level of 0.8, the luminance observed on the pavement increased by only 7.8 percent. In contrast, pavement materials with diffuse reflection can significantly improve both luminance and uniformity. Light-colored stones pavements demonstrated the highest energy-saving performance, achieving a reduction of up to 28 percent in energy consumption per kilometer when the embedding amount reached 6 kg/m2. Additionally, poured semiflexible (PSF) pavement material also improves luminance and uniformity of tunnel pavement, yielding energy savings of up to 18%.