Evaluating Fatigue-Damage of Asphalt Binder and Mastic Modified with Nano-Silica and Synthesized Polyurethane Using VECD Method

Abstract

In this study, the fatigue performance of asphalt binder and mastic containing nano-silica and synthesized polyurethane was evaluated. Modifiers were used in three values of asphalt binder weight. The asphalt binder does not work alone in the asphalt mixture, but its combination with the filler is known as an active substance in the reaction. Superpave fatigue parameter (G*sinδ), time sweep (TS), and linear amplitude sweep (LAS) tests were used to evaluate the fatigue. The viscoelastic continuum damage (VECD) model has been successfully implemented for investigation of the fatigue damage in asphalt binder materials. The VECD method was utilized due to higher precision in measurement, less time consumption of test execution, and being model-based approach resulting in less number of tests required for each strain level. Fourier-Transform Infrared Spectroscopy (FTIR) was used to evaluate chemical structure. Johnson’s criteria cannot be used to estimate the fatigue life of mastic in this regard; the maximum shear stress criterion is reliable to evaluate fatigue performance of mastic. Results of this study indicated that damage mechanism in asphalt binder and mastic, especially in high strains, is different from that of modified and neat asphalt binder. Furthermore, the parameter of damage intensity is a good criterion for evaluation of fatigue performance in asphalt binder and mastic.