Chemical and rheological characteristics of accelerate aged asphalt binders using rolling thin film oven

Abstract

The SUPERPAVE (Superior Performance Pavements) system and design method uses a rolling thin film oven (RTFO) test in the laboratory to simulate short-term ageing. The accelerated asphalt ageing method to simulate the long-term ageing. Whereas the method accelerated asphalt ageing using a pressure ageing vessel (PAV) takes an extended period of time to prepare the samples. In this case, the present study is an attempt to achieve accelerated long-term aged binder similar to that of PAV by running multiple cycles of RTFO maintained at 163 °C for a duration of 85 min per cycle. To achieve this, two unmodified binders of PG 70-XX were obtained from two different sources, and a styrene–butadienestyrene (SBS) modified binder of PG 64-XX was selected. The rheological characteristics such as viscosity at elevated temperature using rotational viscometer (RV), rutting and fatigue parameters using dynamic shear rheometer (DSR), the chemical characteristics such as carbonyl and sulfoxide indices using Fourier transform infrared spectroscopy (FTIR) are used to compare between the RTFO and PAV aged binders. The rheological results suggest that, to produce an accelerated aged binder using RTFO for unmodified and SBS modified asphalt binder with respect to G*sinδ, the RTFO duration of 5 h 20 min and 6 h can be used as alternative for ASTM D6521 respectively. In additions, the rutting parameter G*/sinδ shows to match its PAV aged binder properties at 256 ± 6 min for both PG 70-XX, and 269 min for PG 64-XX modified binder. Further, the variations in functional group concentration and changes in volatile mass are limited the achievement of specific RTFO duration.