Evaluating the effect of nano-clay and nano-alumina on the fatigue response of bitumen using strain and time sweep tests

The effect of nano-clay and nano-alumina on the fatigue life of bitumen was investigated. Bitumens containing 2, 4 and 6% of these additives underwent cyclic loading at strains of 2, 3.5 and 5% using time sweep DSR test. Frequency sweep test was accomplished to present the rheological properties of bitumens. Strain sweep test was performed to investigate the linear and nonlinear viscoelastic behavior. The results indicated that by adding nano-materials to bitumen, the linear viscoelastic limit declined by increasing the shear modulus. The results of time sweep test suggested increased fatigue life of the modified bitumens compared to base bitumen.