Characterisation of a hybrid plant-based asphalt binder replacement with high reactive phenolic monomer content

The present study was undertaken to formulate a hybrid plant-based modifier to replace at least 20% of a non-polymer-modified asphalt binder (non-PMB). Different amounts of two types of lignin (L1 and L2) having high reactive phenolic monomer contents and a corn-based recycling agent (RCA) were shear-mixed with a PG 58-28 binder. Rheological properties of binder blends and those of neat PG 58-28 and PG 64-28 (PMB) were characterised. Also, their adhesion to granite and quartzite aggregates was evaluated. Furthermore, asphalt mixes containing neat PG 58-28 and that modified by different amounts of L1, L2, and RCA were produced and their resistance to cracking, rutting, and stripping was evaluated. While incorporating 25%L2 + 2%RCA in PG 58-28 was found to improve its resistance to rutting and thermal cracking, using 25% L1 caused excessive binder embrittlement. Incorporating L1, L2, or RCA in PG 58-28 was not found to have an adverse effect on binder-aggregate adhesion. Achieving a PG 64-28 binder (PMB) was found to be feasible by incorporating 25%L2 + 2%RCA in PG 58-28 binder while replacing 21.3% of virgin binder. Asphalt mixes containing L2 or a combination L2 + RCA exhibited resistance to cracking, rutting, and stripping which were higher than those of the control mix.