Correlation between rheology and chemical composition of aged polymer-modified asphalts

• The study explores correlation between chemistry and rheology of aged PMA.
• Severity of aging procedure, polymer content and its concentration affect PMA viscosity.
• Complex shear modulus can be fairly estimated from chemical composition elucidated by ATR FT-IR.
• Polymer concentration can be backcalculated from absorbance spectrum of PMA.

This study explores correlation between chemical and rheological changes in polymer-modified asphalts (PMA) aged in laboratory. Viscosity measurements were conducted in Dynamic Shear Rheometer (DSR), whereas the changes in asphalt chemical composition due to aging were elucidated from their Fourier transform infrared spectra obtained in Attenuate Total Reflection (ATR) mode. The analysis of variance in DSR and ATR measurements revealed that severity of aging procedure affected PMA viscosity greater than polymer composition and concentration did. Furthermore, it was possible to predict dynamic shear modulus of PMA at a given temperature and aging test severity from relative content of chemical functional groups identified from ATR spectrum.