Influence of red mud filler on the fatigue behaviour of bituminous mastic

The objective of this research was to investigate the influence of volume fraction of red mud filler on the fatigue behaviour of bituminous mastic at intermediate temperature range. The experimental programme included linear amplitude sweeps and frequency sweeps of long-term aged mastic specimens with the volume fractions of red mud filler of 10, 20, and 30 %, which enabled the determination of fatigue functions. It was found that the increase in the volume fraction of filler above 20 % had almost no influence on peak shear stress. The linearity limit of shear strain amplitude was especially low (below approximately 1 %) and decreased with the volume fraction of filler. Within the linear viscoelastic domain, the volume fraction of filler had a distinct influence on complex hear modulus, while its influence on phase angle was minor. The rate of fatigue damage increased with the volume fraction of filler, but no significant improvement took place above 20 %.