Glass beads are solid glass spheres. Because of their high strength, chemical stability, low thermal expansion, and good flowability, they are manufactured from colorless glass for many industrial purposes. In recent years, the urban heat island (UHI) phenomenon has become very serious in urban centers. Heat emitted from exterior walls of buildings accounts for a relatively large proportion of total anthropogenic waste heat. Retroreflective (RR) materials are researched worldwide for the potential in application to building exterior wall surface instead of normal diffuse highly reflective (DHR) materials to resist the UHI. Glass beads are the common main components of these RR materials. Glass beads have different refractive indices and diameters. The classification and reflection principles of glass beads, experimental analysis on the optical properties and thermal performance of glass bead RR materials are elaborated in detail in this chapter. In addition, if these glass bead RR materials are used in building facades, when the incident angle of the sun is very high, the facade will produce a large specular reflection to the road, which may cause adverse effects on pedestrians. Therefore, theoretical and technical aspects of preventing the specular reflection from glass bead RR materials should be studied and implemented.
Part of the book: Advances in Glass Science and Technology