Scientists explore the durability of glass bead RR materials.
In a new study published by Science Direct, several glass bead retro-reflective (RR) materials with different refractive indices and different colour reflective layers were developed. The long-term change in solar reflectivity and angular distribution of reflection intensity for these glass bead RR materials was evaluated for purpose of durability verification.
According to the study reports, heat from buildings contributes about half of the city’s anthropogenic heat to the urban heat island (UHI). The ratio of heat emitted from building external walls occupies about one third of the anthropogenic waste heat total in Japan. Retro-reflective (RR) materials applied to building facades instead of highly reflective (HR) materials for UHI mitigation are being studied.
The result showed that both the solar reflectivity and angular distribution of reflection intensity for these developed glass bead RR materials almost have no significant change after 368 days of exposure in the outdoor environment. Additionally, the study found that the glass bead RR material with a refractive index of 1.9 has much better RR performance, compared to that with a refractive index of 1.5.
The study can be found online at: https://www.sciencedirect.com/science/article/pii/S0300944017307312.