Performance evaluation of bio-based asphalt and asphalt mixture and effects of physical and chemical modification

Adding bio-binder (BB) into petroleum-based asphalt (BA) to produce the sustainable pavement material of bio-based asphalt (BBA), and replace the BA partially or even fully could reduce the dependence of pavement engineering on fossil fuels. This study aims to investigate the effects of adding single-source BB from corn on asphalt binder and asphalt mixture performance. Rheological properties measured from Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) showed that addition of BB increased the viscosity while decreased the temperature susceptibility of asphalt binder, the BBA became stiffer at high temperatures and more brittle at low temperatures. Pavement performance tests conducted at mixture level showed that adding BB is capable of improving rutting resistance while sacrificing low-temperature cracking resistance slightly, but moisture damage resistance decreased evidently. Therefore, chemical characterisation of BB and BA was conducted using Elemental Analysis, Gas Chromatography-Mass Spectroscopy (GC-MS), Fourier-Transform Infrared Spectroscopy (FTIR) and Saturates, Aromatics, Resins and Asphaltenes (SARA) Fractions Analysis was employed to investigate the performance variation mechanism due to the addition of BB. The results proved that a certain number of light and soluble components existed in BB. After that, physical and chemical modifications with the modifiers of Styrene-Butadiene-Styrene (SBS) block copolymer and o-Phthalic anhydride, respectively, were adopted to improve the performance of BBA. Mixture performance tests showed that physical method improved high- and low-temperature performance obviously while had no effect on moisture damage resistance. On the other hand, the chemical approach enhanced moisture damage resistance of mixture visibly while not affecting other performance criteria. The study findings emphasised that utilising BBA proposed to partially replace BA is potential and feasible with appropriate modification.