Effect Of Bio-Binders On Binder And Mix Properties With High Rap Content

The use of Recycled Asphalt Pavement (RAP) has significantly increased in construction and rehabilitation of flexible pavements to ensure proper utilization of limited natural resources. Recycling also provides a greater environmental benefits and energy conservations. It saves the lands from being the dumping site, conserves energy, and reduces the emission of greenhouse gases. But high RAP in the HMA mix increases the stiffness and may result in cracking. Bio-binders could reduce the stiffness of binder and mixes with high RAP content. Two oils, namely Waste Cooking Oil (WCO), and Soy Oil are potential sources of bio-binder that are abundant and yet to be explored. This research was conducted to explore the effects of selected bio-binders on binder and mixture properties that contain a high percentage of RAP binder. Two different types of aggregates and two virgin binders were used in the study. RAP binder was extracted and modified by the bio-binder. Unaged, Rolling Thin Film Oven (RTFO), and Pressure Aging Vessel (PAV) aged virgin and bio-binder modified RAP binder were tested for both high and low-temperature rheology using Dynamic Shear Rheometer (DSR). Virgin binders were tested as control specimen while 100% RAP binder was used to see the level of modification of RAP binder. These modified binders were further used to make HMA specimens. Nominal maximum aggregate size (NMAS) used for all mixes was 12.5 mm. Eight specimens (150 mm diameter and 75 mm high each) were compacted at a target 7% air void content using gyratory compactor. Asphalt Pavement Analyzer (APA), Semi-Circular Bending (SCB), and Disk-shaped Compact Tension (DCT) tests were conducted to determine the performance properties of the HMA with modified binder. The results showed that modified binder with bio-binder, virgin binder, and high RAP binder maintained/improved the performance properties of HMA