Bitumen Colloidal and Structural Stability Characterization

ABSTRACT Turbidimetric titration and analysis using SARA (Saturates, Aromatics, Resins and Asphaltenes) were done for bitumen, aged bitumen and recycled bitumen, and their index of colloidal stability (P) and Gaestel Index (iC) were calculated. The results show that with deep aging of the bitumen, its colloidal stability decreases. Changes in the SARA fractions influence the colloidal stability of the bitumen. The asphaltenes is the most influential factor. The recycling effect of rejuvenator C was good and that of rejuvenator A was bad. Higher aromatics, moderate saturates and lower asphaltenes content of the rejuvenator can produce a good regeneration effect. Hence, the colloidal stability of aged bitumen can be restored when the proper rejuvenator is chosen. The structural stability of bitumen was characterized using a three-dimensional titration. The experimental results indicate that for the bitumen after PAV aging, polar interactions and hydrogen bonding are stronger than that of unaged bitumen, but the dispersive force is lower.