Modification Mechanism of Using Waste Wood–Based Bio-Oil to Modify Petroleum Asphalt

Abstract

The aim of this research is using a waste wood–based bio-oil as the modifier of petroleum asphalt and analyzing its modification mechanism. The four components, infrared spectrum, and molecular weight distribution analysis were performed to investigate the chemical performance of control binder and bioasphalts. A conventional petroleum asphalt PG 64-22 was employed as the control binder. The bio-oil with addition of 10%, 15%, and 25% by weight was used to prepare bioasphalts (BMA). Meanwhile, the Gas Chromatograph Mass Spectrometer (GC-MS) and oven heating tests were conducted to explore the chemical compounds and their approximate contents in bio-oil. Results demonstrated that the bio-oil significantly changed the contents of chemical components in asphalt binder by decreasing the contents of saturates and asphaltenes and increasing the aromatics and resins contents. The modification of petroleum asphalt by bio-oil is not only a physical mixing but also a chemical process. Some chemical reactions were deduced between the PG 64-22 and bio-oil based on the infrared spectrum analysis. The added bio-oil converted some large molecules into small molecules. There are various chemical compounds in the bio-oil. Higher content of aromatic compounds and many lightweight compounds can explain the softer quality of bioasphalt and its inferior high temperature properties in comparison to petroleum asphalt.