| Summary: | Reclaimed asphalt pavement (RAP) is a material frequently used in asphalt mixtures. As asphalt industries strive for sustainability, more RAP materials are used in new pavements. However, the biggest drawback in using RAP is the deterioration of the binder's characteristics as it ages. This is because as the asphalt binder ages, the ratio of maltenes to asphaltenes reduces, thus making the binder stiffer and brittle. The use of rejuvenators in RAP containing asphalt mixture has the potential to restore the balance between the asphaltenes and maltenes like those of 60/70 grade virgin binder. This study aimed to investigate the performance of reclaimed asphalt pavement with Waste Engine Oil (WEO) and Polyethylene terephthalate (PET) as a rejuvenator. Phase I involved the aminolysis process of converting the PET bottles into a PET-derived additive (glycol). Phase II involved the production of polymer-modified binder (PMB) and extraction of RAP binder (RB). The virgin binder (VB) was mixed with 2% of a PET-derived additive to produce a polymer-modified binder (PMB). Various percentages WEO of 3%, 4%, and 5% by weight of the total binder were then added. This PMB mixed with different percentages of RAP binder (RB), specifically 30%, 40%, and 50%. The physical properties of binder samples were evaluated using several tests, including penetration, softening point, ductility, viscosity, storage stability, and penetration index. Rheological properties were assessed using a Dynamic Shear Rheometer (DSR), while chemical properties were analysed through Scanning Electron Microscopy (SEM), Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetric Analysis (TGA), and Atomic Force Microscopy (AFM). All rejuvenated asphalt binder samples were compared with 100% virgin binder penetration grade 60/70 (VB100) and 100% RAP binder (RB100). In Phase III, various mechanical performance tests were conducted to assess the rejuvenated asphalt mixtures. From Phase I, it was found that the aminolysis of PET bottles with triethylenetriamine (TETA) successfully produced PET additives with improved properties and functional groups. From Phase II, results reveal that binders with 30% RB rejuvenated with 5% WEO exhibited the best physical properties. Rheological improvements were noted, with reduced stiffness and ageing due to WEO's rejuvenating effects. SEM results show complete PET dissolution, results homogeneous solution. FTIR analysis indicates similar functional groups across asphalt binders without new chemical reactions. TGA results highlight improved thermal stability at higher temperatures, while AFM reveal reduced ageing levels and smaller bee-like structures compared to VB100 and RB100. From Phase III, it was found that the combination of 70% PMB and 30% RB, along with 5% WEO, results in a rejuvenated asphalt mixture with reduced stiffness, as well as increased flow and tensile strength ratio (TSR) values. It also performs well in terms of fatigue cracking and rutting resistance. The rejuvenated asphalt mixtures also demonstrated reduced water susceptibility in both static and total immersion tests. This study finds that using hybrid rejuvenator made from waste PET bottle and WEO for road construction is valuable.
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