Assessment of Asphalt Rheological Behaviors by Studying Their Aromatic Structures

Abstract

Assessment of asphalt rheological behaviors during road service life requires to better know original asphalt chemical structures responsible of its main mechanical features. For this purpose, the nature of the asphalt chemical structures were characterized by using Fourier transformed Infrared (FTIR) and Synchronous UV Fluorescence (SF) spectroscopies. Indices based on the ratios of some FTIR absorption bands were established to evaluate aromatic and aliphatic structure contents of 10 asphalt cements. For instance, valuable information about aromatic families was obtained from SF indices which were related to FTIR indices. Relationships between these structural characteristics and the rheological properties were evaluated using Principal Component Analysis and Multivariate Linear Regression. As a result, bitumen rheological properties, at low or at high temperature, were found to greatly depend on the aromatic substitution and condensation degree, the aliphatic/ aromatic structure ratio and the vanadium contents. Hence, some rheological properties could be predicted from less than five SF/FTIR indices.

Key Words:

• Asphalts
• Structural indices
• FTIR
• Synchronous UV Fluorescence
• Prediction of asphalt rheological properties