Modification of asphalt binder using bio-oil and bio-char from oil palm biomass

Abstract

Agriculture biomass is found to be a potential alternative to petroleum asphalt binder used in pavement due to its carbon nature and morphology. Efforts have been made to look for practical applications of biomass. Bio-oil (BO) and bio-char (BC) derived from biomass of oil palm empty fruit bunches (EFB) could produce a wide range of products including energy source, chemicals and raw materials. Therefore, the aim of this study is to investigate the performance of asphalt binders modified by BO and BC generated from oil palm EFB biomass. In the first phase, pyrolysis process was carried out to produce BO and BC from oil palm EFB biomass. A new laboratory-scale machine has been designed for this purpose. BO and BC were characterized based on density test and elemental analysis. In the second phase, these additives were incorporated into 80-100 PEN asphalt binder at different percentages (0%, 5%, 10% and 15%) in order to obtain the recommended additive content. All samples were tested in the laboratory for their physical, rheological and chemical properties. Penetration, softening point, viscosity, storage stability, dynamic shear rheometer (DSR) and Fourier transform infrared (FTIR) tests were performed on the modified asphalt binder. The recommended amount of 5% BO and 5% BC were then be used in phase three for two types of asphaltic concrete mixtures. Mixtures with 14 mm nominal maximum aggregate size (AC 14) consisting 100% fresh aggregate (fresh mixture) and 60% fresh aggregate incorporated 40% reclaimed asphalt pavement (RAP) aggregate (RAP mixture) were tested. The performance tests include resilient modulus, dynamic creep and indirect tensile strength tests. Based on the findings, addition of BC shows 14% increment in rutting and fatigue resistance performance of fresh mixture. However, no significant improvement on performance of RAP mixture with the addition of BO and BC.