Photoluminescent road surface dressing: a first laboratory experimental investigation

The main objective of this experimental research was to analyze the possible use of afterglow photoluminescent pigments for road wearing courses. Thanks to their natural color or their glowing color, depending on their emission spectra, photoluminescent pigments could allow a better identification of different pavement zones in the darkness. We studied two type of pigments (masterbatches and powders), based on zinc sulfide (ZnS: Cu) or on strontium aluminate phosphors (SrAl2O4: Eu (2+), Dy (3+)), in different experimental conditions. Firstly, experiments were performed to determine the crystals' luminescent properties. Next, we investigated possible application of these materials in asphalt concrete and slurry seal, prepared by using clear binder and synthetic bitumen emulsion. The representative samples of photoluminescent Strontium Aluminate surface dressing were able to re-emit energy in the form of visible light for significant period of time, after exposure to daylight or artificial light. Assuring good performances in different condition, they could be having interesting suitable applications in a wide variety of contexts: low-volume roads, footpaths and bicycle lanes.