Molecular structure evolution of asphaltite-modified bitumens during ageing; Comparisons with equivalent petroleum bitumens

This work focuses on the molecular structure evolution of asphaltite-modified paving bitumens during ageing. In order to quantify the effect of ageing on the molecular weight distribution (MWD) of bitumens, a new parameter, called hereafter the ageing molecular-distribution shift (AMDS), is introduced. The molecular evolutions of asphaltite-modified bitumens during aging are compared with the molecular evolutions of pure petroleum bitumens of equivalent grade. The results based on AMDS confirm previous research showing that the asphaltite attenuates the ageing and, compared to hard petroleum bitumens produced in refinery, the asphaltite-modified bitumens present a better ageing performance. The AMDS parameter reveals appropriate for the evaluation of evolutions due to ageing. Keywords: Asphaltite, Bitumen modification, Bitumen aging, Molecular weight distribution of bitumen