Influence of luminescent powder type and characteristic on the glow light performance of architectural glass mortar

Abstract

The effect of luminescent powder (LP) type and characteristics on the properties of architectural luminescent glass-mortars (ALM) was investigated. Four LPs including ZnS:Cu (LP1) and SrAl2O4:Eu2+,Dy2+ (LP2-4) with different particle sizes and surface conditions (with or without a protective layer) were coated on the surface of glass particles using an adhesive paint for producing luminescent glass (LG). LG was then used to replace coarse aggregate in conventional glass mortar for the production of ALM. The results showed that all ALMs obtained good fresh properties and mechanical strength (>40 MPa) with proper excitation and emission wavelengths ranging from 250 to 450 nm and 500–560 nm, respectively, demonstrating the feasibility of fabricating decorative concrete. Regarding the glow light performance, SrAl2O4:Eu2+,Dy2+ outweighed ZnS:Cu in all luminescent indexes including initial brightness (luminescent intensity), decay rate, and afterglow time. Coarser LP attained lower luminescent intensity but a better decay rate due to the its relative lower specific surface area. A protective layer on the LP surface (surface condition) inhibited its light absorption and emission capacity, leading to poor luminescent performance. The adhesive paint used for producing LG, having poor UV aging resistance, was susceptible to sunlight degradation, reflected by colour turning into brown. The darker colour reduced its light transmitting efficiency, inducing a decrease in glow light performance of ALM. The excellent water and wearing resistance of ALM allowed maintaining their luminescent performance under extreme environment conditions.