THE FLUOROMETRIC CHARACTERIZATION OF ASPHALTS

ABSTRACT

Fluorescence microphotometry has been used as a technique for the characterization of asphalt binder quality and the deterioration of asphalt cements. The technique employs optical microscopy for the in situ identification of asphalt binder from aggregate materials in cements, thereby eliminating the need to solvent extract the binder for evaluation. It may also obviate the possibility of solvent interaction or interference with the physical and chemical properties of asphalt binders that have developed in-service.

In this research effort a standard technique for the measurement of fluorescence intensity has been developed and applied to the characterization of twelve raw asphalts. These studies were first necessary before undertaking the more difficult task of measuring asphalt binder fluorescence in cements. Analytical techniques and some of the factors which influence asphalt fluorescence have been considered. With this small sample set, relationships appear to be emerging between original asphalt viscosity as well as the viscosity of laboratory-aged asphalts and fluorescence intensity. As viscosity increases, intensity decreases, suggesting that quantitative fluorescence may be used as a measure of the molecular associations that result during asphalt hardening