Effect of Graphene Nanoplatelets (GNPs) on Fatigue Properties of Asphalt Mastics

To investigate the effect of graphene on the fatigue properties of base asphalt mastics, graphene nanoplatelets (GNPs)-modified asphalt mastics and base asphalt mastics were prepared. A dynamic shear rheometer (DSR) was used to conduct the tests in the stress-controlled mode of a time-sweep test. The results showed that GNPs can improve the fatigue life of asphalt mastic. Under a stress of 0.15 MPa, the average fatigue life growth rate (ω¯) was 17.7% at a filler-asphalt ratio of 0.8, 35.4% at 1.0, and 45.2% at 1.2; under a stress of 0.2 MPa, the average fatigue life growth rate (ω¯) was 17.9% at a filler-asphalt ratio of 0.8, 25.6% at 1.0, and 38.2% at 1.2. The growth value (ΔT) of fatigue life of GNPs-modified asphalt mastics increased correspondingly with the increase of filler-asphalt ratio, the correlation coefficient R² was greater than 0.95, and the growth amount showed a good linear relationship with the filler-asphalt ratio. In the range of 0.8~1.2 filler-asphalt ratio, the increase of mineral powder can improve the fatigue life of asphalt mastics, and there is a good linear correlation between filler-asphalt ratio and fatigue life. The anti-fatigue mechanism of GNPs lies in the interaction between GNPs and asphalt, as well as its own lubricity and thermal conductivity.