Effects of aging on rejuvenated vacuum tower bottom rheology through use of black diagrams, and master curves

Abstract

Bio-derived rejuvenating agents have the potential to enhance the rheological properties of the vacuum tower bottoms left over from the crude oil refining process. Enhancement of the rheological properties allows the stiff vacuum tower bottoms to be used as an asphalt binder in hot mix asphalt. This study investigates the use of several experimental bio-derived rejuvenating additives and compares them with a commercially available modifier. The experimental additives include a blend of, heat bodied linseed oil (HBO) and partially hydrogenated heat bodied linseed oil (PHBO). The effect of dosage level and aging influence on rheological properties was studied for the experimental materials and the commercially available additives. The findings show that all the rejuvenators used had similar effects in the reduction of vacuum tower bottom stiffness due to short-term and long-term aging. However, the commercial rejuvenator reduced stiffness the most. The results show that the material combination of HBO and PHBO better retain high temperature properties while lowering stiffness at intermediate and low temperatures, thus widening the continuous grade range better than the commercial rejuvenator. To better understand why these effects are taking place in vacuum tower bottoms from both the commercial rejuvenator and the combination of materials HBO and PHBO with aging it is felt that in the future analytical chemistry such as high definition mass spectrometry needs to take place. This will make it possible to understand why these effects are taking place with aging.