Physical, rheological, and FTIR-based chemical properties of reclaimed asphalt pavement from varied sources in a single climatic region

This study investigates the effects of reclaimed asphalt pavement (RAP) content and source on asphalt mix performance, analyzing eight RAP sources from the Montreal area. It characterizes the physical, rheological, and infrared absorbance properties of RAP materials, RAP aggregates and extracted bitumen. The research finds that finer RAP has a higher bitumen content, while RAP aggregates display consistent intrinsic properties. Significant variability in rheological properties is observed in RAP bitumen, particularly in finer RAP, indicating the presence of polymers and stiffer bitumen. The 2S2P1D model, applied for assessing linear viscoelastic behaviour, corroborates these observations. Furthermore, FTIR indices offer insights into bitumen oxidation, enhanced by including two virgin bitumens in the analysis. The sulphoxide and long chain indices appear to be reliable indicators for categorizing the oxidation level of bitumen. This study highlights the critical need for detailed RAP characterization to optimize asphalt mix performance and encourage more effective recycling in asphalt production.