Bio-based palm oil as an additive for asphalt binder: Chemical characterization and rheological properties

Abstract

The asphalt industry has been increasingly concerned with solutions to develop new binder materials from sustainable resources that meet environmental and technical criteria. In this context, binder flow modifiers emerged as an alternative to reduce mixing and compaction temperatures, influencing binder performance. This study evaluated the effect of hydrogenated palm oil fat (HPF) and hydrogenated palm fat amide (FAA) - synthesized from palm oil - on the empirical, chemical, and rheological properties of asphalt binder (AB). The HPF and FAA were characterized by Fourier Transform Infrared Spectroscopy (FTIR), 1H and 13C Nuclear Magnetic Resonance NMR, Thermogravimetric Analysis (TGA and DSC). The additives presented good thermal resistance for paving applications and behave as low-viscosity modifiers, improving the workability of the asphalt binders reducing mixing and compaction temperatures. The additives have little effect on the rutting resistance at higher temperatures; however, HPF promoted greater resistance at lower temperatures. After short-term aging it was observed that both HPF and FAA present a rejuvenating effect. The peculiarities of crystalline phases of HPF and FAA, which results in different melting temperatures, was recognized to be responsible for the rheological effects linked with viscoelasticity. The results highlight the potential of using derivatives of palm oil as a binder flow modifier, with technical, economic, and environmental benefits.