A Comparative Study of RTFO, PAV and UV Aging Using FT-IRS and DSR Tests

The objective of this study was to investigate RTRO (Rolling Thing Film Oven), PAV (Pressure Aging Vessel), UV (Ultraviolet), and forced draft oven aging behavior of original binder through dynamic shear rheometer (DSR) and FT-IRS (Fourier Transform Infrared Spectrometer). Different aging equipment, namely RTFO, PAV, UV chamber, and forced draft oven, were used to age the binder until equal stiffness (same G*/sinδ) was obtained. A comparison has been performed among these four aging procedures based on their differences in chemical and rheological properties. FT-IRS was used to envisage the chemical alteration, whereas DSR was used to perceive the rheological changes. Samples were prepared in RTFO at 163 °C and were collected at different degrees of RTFO aging. PAV, UV, and oven aged samples were prepared considering conditions without RTFO aging. Results showed that carbonyl (C=O) and sulfoxide (S=O) content of different degrees of RTFO and PAV aged samples increased with duration. On the other hand, C=O and S=O content in UV and oven aged samples decreased after 36 h of aging. At similar stiffness of RTFO and PAV aged binders, C=O content was similar, but S=O content was higher in PAV aged binders. DSR results also showed a resemblance with the FT-IRS results, which indicated that these different aging procedures with different equipment could be correlated with each other.