CHARACTERIZATION STUDIES ON VISBREAKER RESIDUES AND BITUMENS

Abstract
To better characterize the visbreaker (VB) residues and bitumens, and to study the differences between visbreaker and stright run (SR) products, four groups of samples (VB and SR residues and bitumens) were produced in some italian refineries. The samples were tested and analysed in order to know their viscosity at various temperatures, and their composition (chemical analysis and nmr). Adhesion, stability to oxidation, flow resistance of asphalt concrete were also evaluated for the bitumens. The study showed that nmr-aromaticity of the visbreaker residues and bitumens was increased by the visbreaking operation. Visbreaker bitumens were sensitive to oxidation and gave higher Marshall resistances. The susceptibility of penetration and viscosity to temperature changes was higer for visbreaker bitumens.