Studies on the aging behavior of the Arabian asphalts

In this study the rheological, physical, and chemical properties of asphalts procured from Ras Tanura, Riyadh, Kuwait, and Bahrain refineries were evaluated. The rolling thin-film oven (RTFO), termed as short-term aging, and the pressurized aging vessel (PAV), termed as long-term aging, tests were used to simulate asphalt aging. Viscosity, penetration, softening point, and weight loss tests were applied to investigate the rheological properties of fresh and aged Arabian asphalts. The Corbett method was used to separate asphalts into asphaltene, polar aromatic, naphthene aromatic, and saturate fractions. Asphaltene contents and Gaestel index (Ic) were found to increase linearly with aging process. It was found that PAV has more severe effects on the rheological and chemical properties of asphalt than RTFO test method. Using infrared spectroscopy, it was found that on aging the weight percent of oxygen as carbonyl and sulfur as sulfoxide group types increased in asphaltenes. Significant differences were observed between the structure and composition of fresh and aged asphaltenes of Ras Tanura (RT) asphalt. (C) 1999 Elsevier Science Ltd. All rights reserved.