Porosity–grouting–luminescence coupling mechanism and durability of semi-flexible self-luminous pavements

The development of self-luminous pavements offers a promising strategy to enhance nighttime road visibility and reduce external lighting energy consumption. This study proposes a semi-flexible self-luminous (SFSL) pavement by filling the interconnected voids of porous asphalt with a cement-based luminescent grouting system containing long afterglow phosphors (SrAl₂O₄: Eu²⁺, Dy³⁺). A comprehensive evaluation was conducted to correlate porosities, grout setting time, and filling efficiency with the luminescent area and optical performance. High-precision image recognition based on OpenCV algorithms was introduced for quantitative analysis of luminous coverage, enabling accurate assessment of luminescence uniformity. The results indicate that porosities of 20–22% and a grout setting time within 25 min achieve optimal light-emitting efficiency and penetration depth (~20 mm). A strong linear correlation (R² > 0.93) was found between the connected voids and the luminous area. Mechanical and durability evaluations revealed that SFSL pavements maintain excellent rutting resistance, skid resistance, and water stability, while a moderate reduction in low-temperature flexibility was observed. Outdoor illumination tests demonstrated persistent luminescence exceeding 6 h under natural solar excitation, even in cloudy conditions. Accelerated loading tests identified a three-phase degradation pattern—rapid, stable, and slow decay—characterizing the attenuation of both optical and skid resistance performance. This research establishes the mechanism of porosity–grouting–luminescence coupling in semi-flexible systems and provides quantitative design guidance for balancing structural strength, durability, and energy-saving functionality. The proposed SFSL pavement system demonstrates substantial potential for sustainable and self-illuminated roadway applications.