Bitumen is manufactured from different crude oil sources also by various refining technologies, therefore, the impact of ageing is different. Bitumen is a complex chemical mixture consisting of a large number and diversity of organic compounds, mostly hydrocarbons, and varying in molecular mass, polarity and aromaticity. Various polar and non-polar fragments in bitumen interacting in-between form the certain structures which changes bitumen behaviour. Since bitumen is assigned as a colloidal system, consisting of high molecular weight asphaltene micelles dispersed in a lower molecular weight maltenes (saturates, aromatics, resins), the bitumen structure changes over time. Since ageing is one of the main factors effecting bitumen properties and asphalt pavement performance, it is essential to understand how the fractional composition of bitumen is affected by the long-term ageing simulation in the laboratory. The main purpose of this article is to analyse bitumen ageing process and influence to bitumen fractional composition (saturates, aromatics, resins, and asphaltenes), i.e. to show what happens to the bitumen fractional composition and colloidal stability when bitumen reaches a critical ageing point. The saturates, aromatics, resins, and asphaltenes were determined with the Thin Layer Chromatography with flame-ionisation detector (TLC/FID), the IATROSCAN MK-6s.

bitumen; fraction composition; SARA; aging; oxidation; colloidal stability