N. Tabatabaee - Associate Professor, Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
M. Z. Alavi - Graduate Student, Department of Civil Engineering, Sharif University of Technology, Tehran, Iran

Crumb rubber modifier (CRM) is known to have a positive effect on the properties of typical paving asphalts. In this paper, the effect of CRM on the performance properties of vacuum bottom, a residuum from the vacuum tower of a crude oil refinery plant, is investigated using the Superpave testing protocol. Initial results show that rubber modification increases viscosity, enhances high service temperature, and expands intermediate service temperature range as defined in performance grade superpave specifications. The effect of this modification on low service temperature is positive, but less pronounced compared to high and intermediate service temperatures.

Keywords Vacuum Bottom residuum, Crumb rubber modifier, Viscosity, Performance grade