Self-luminescent cement-based composite materials: properties and mechanisms

Abstract

Self-luminescent cement-based composite materials (SLCCM) have been considered as an innovatively functional civil engineering material for environmental protection pavement and smart pavement. In this study, luminescent cement-based composite materials (LCCM) were prepared by doping luminescent powder (LP) and reflective powder (RP) into cement-based materials. The mechanical properties and luminous properties, as well as the luminescence mechanism, were evaluated. The results indicate that the incensement of RP mesh improved the mechanical strength of the LCCM specimen, while the mechanical strengths, brightness and afterglow time of the LCCM first increase and then decrease with an increase in the mesh of the LP. The LP and RP reacted with cement hydration products to produce abundant C-S-H. However, when the particle size was too small, SrAl2O4 could hydrolyzes to produce SrAl4O7, furthermore, a large amount of aluminum ions in the LP are free, which accelerates the hydration reaction of Ca(OH)2 to produce C-S-H and AFt crystals. The self-hydration of LP and the coverage of hydration products make the luminescent properties of LCCM with fine particles decrease, while the coarse particles have the lowest luminescent properties due to the limited effective luminescent area in cement. The optimum excitation spectrum of the LCCM is found in the range between 350 and 450 nm, and the emission spectrum is yellowish–green with a peak value of 510–520 nm. The comprehensive evaluation results of LCCM show great feasibility of its utilization in road pavement, which is help to save energy, reduce ecological light pollution and improve the safety of road traffic in low lighting environment.