Bio-based Light-Transmitting Concrete for solar-sidewalk applications: Evaluation of mechanical, optical and thermal characteristics

Light-Transmitting Concrete (LTC) provides a sustainable and innovative solution for integrating solar energy harvesting into pavements, addressing the dual goals of energy efficiency and environmental responsibility. This study examined the mechanical, optical, and thermal properties of LTC made with recycled glass and bio-based epoxy, targeting optimization for solar-sidewalk applications. Mixes with varying epoxy-to-glass ratios (4.75–12.7 mm aggregates) were tested for compressive strength, light transmittance, and thermal conductivity. Spectroscopic analysis showed a maximum light transmittance of 69 % in a mix of 48 % epoxy and 52 % glass by volume. The optimized mix achieved a thermal conductivity of 0.43 W/m·K, balancing insulation and structural integrity. Temperature-dependent behavior indicated that epoxy contributed to thermal sensitivity, while glass provided stability. Field testing confirmed the effective integration of LTC with photovoltaic panels, with stable power generation and superior thermal retention, especially under low-irradiance conditions. The LTC module achieved a Levelized Cost of Electricity (LCOE) of $0.57/kWh and avoided 1280 kgCO₂eq/m² of emissions over 20 years, outperforming several conventional PV pavement systems. These findings offer a practical framework for applying LTC in energy-harvesting sidewalks, promoting resilient and eco-friendly infrastructure.