Comparative Characterization of Field and Laboratory-Aged Binders Modified with Antioxidant Additives and Copolymers Using Fourier Transform Infrared Spectroscopy and Gel Permeation Chromatography

This study investigates the behavior of antioxidant additives and copolymers to an asphalt binder by comparing laboratory-aged (up to 60 h) and antioxidant-modified binders with binders extracted from field cores. To evaluate the change in carbonyl, sulfoxide, aromatic, and aliphatic compounds of asphalt binders due to both lab and field-aging, spectral analysis was performed using Fourier transform infrared spectroscopy. A good correlation was found between carbonyl growth and viscosity in the field-aged binders. Chemical analysis with gel permeation chromatography showed that the quantity of large particle sizes increases with the increase in carbonyl growth due to aging. Both Redicote and Solprene were found to retard the growth of large molecular size particles in lab-aged binders when compared to field-aged binders. This study provides further validation of the use of Redicote and Solprene in retarding the aging of asphalt binders. The advanced chemical characterization conducted in this study can be used to evaluate the effectiveness of antioxidant additives and copolymers in retarding oxidative aging and selecting the proper products that work better with specified asphalt binders.