Fatigue Resistance of RCA Modified Asphalt Based on Dielectric Properties

In order to study the anti-fatigue performance of RCA modified asphalt (RMA), the performance of RMA and 90 # matrix asphalt with different modifier content were measured by asphalt penetration, ductility, softening point, Brookfield viscosity, rheological index, infrared spectrum and dielectric constant test. This paper discusses the changes of asphalt basic indexes, fatigue properties and asphalt components based on dielectric properties under different modifier contents, and analyzes the grey correlation degree between components and asphalt pavement performance indexes. The results show that the optimum content of RCA modifier is 16.7% of the asphalt quality according to the penetration, ductility, softening point, Brockfield viscosity, viscosity temperature curve and fatigue life. In the phase angle-strain curve, there is disorder in the latter part of the curve. According to the strain (ε_d) corresponding to the disorder point, a new fatigue failure criterion is proposed and proved. Based on the new asphalt fatigue failure criterion, the fatigue prediction model of asphalt mixture is improved, and the fatigue life predicted by the improved fatigue model is compared with the fatigue life obtained by four-point bending fatigue test. The results show that the proposed new asphalt fatigue failure criterion is reasonable, and the fatigue life predicted by the improved asphalt mixture fatigue prediction model is accurate. The research method of classifying asphalt components based on dielectric properties is simple and effective, and the components have a high correlation with the road performance of base asphalt and modified asphalt.