Chemical characterization and oxidative aging of bio-asphalt and its compatibility with petroleum asphalt

The objective of this paper is to characterize the elemental composition, chemical compounds, oxidative aging and the compatibility of bio-asphalt modified with bio-oil. A petroleum asphalt was modified with treated and untreated bio-oil at 2%, 5% and 10% by weight to prepare bio-asphalt, respectively. Gas chromatography-mass spectrometry (GC-MS) was employed to characterize the chemical compounds in the bio-oil. The Fourier Transform Infrared Spectroscopy (FTIR) was utilized to explore the influence of bio-oil on the aging performance of asphalt. The compatibility of bio-oil with petroleum asphalt was investigated using automated flocculation titrimetry (AFT) based on flocculation stability. The elemental composition analysis revealed a higher amount of oxygen in the bio-oil. The GC-MS results showed the presence of chemical compounds with low boiling temperatures, which have potential environmental impacts and health concerns if used in hot mix asphalt. The FTIR results indicated the presence of aromatic and nitrogenous compounds, alcohols, ethers, ketones, carboxylic acids, aldehydes, esters, acyls, alkanes, polymeric OH, NH2 and water. The AFT results implied a stable and compatible mixture of 2% bio-asphalt. The study also suggested that with an increase in the fraction of bio-oil, the compatibility with petroleum asphalt would decrease.