The effect of fly ash on the rheological properties of bituminous materials

To assess the effect of fly ash on the rheological performance of asphalt cement, a dynamic shear rheometer was used to measure the binder's resistance to shear deformation in the linear viscoelastic region. The rutting factor, G*/sin(δ) and dynamic viscosity, η′, were determined for different types of bitumen at different temperatures, with 5%, 15%, 30% and 60% of binder replacement by weight of fly ash class C and F. The addition of fly ash improved the rutting factor and reached a higher performance grade of the binders. The viscosity for both bitumen types increased at 124 °C degrees, but for the most of the compositions it remained within the range for mixing and placement of asphalt concrete.