Abstract:
The effectiveness of natural Gilsonite on the performance properties of modified bitumens was studied. Three samples having different ratios of Gilsonite that are 6%, 8% and 10% by weight of base bitumen which was PG 64-16 grade were prepared. The physical properties and storage stabilities of four samples were investigated by means of conventional tests. The short-term and long-term aging processes of bitumens were conducted with rolling thin oven and pressure aging vessel tests, respectively. Rheological properties of bitumens were examined by means of Superpave tests such as rotational viscosity, dynamic shear rheometer and bending beam rheometer. After the rheological study, the low and high temperature performance classes of bitumens were determined by the Superpave specification. The results showed that natural Gilsonite-modified bitumens provide improvement in rheological and physical properties of bitumen, and were found highly compatible with base bitumen. Gilsonite additive significantly increased stiffness and viscosity of bitumen, and improved the resistance against fatigue cracking and rutting of bitumen, without causing a reduction in thermal cracking resistance of bitumen.
