Oscillatory shear testing is commonly used in characterizing the fatigue performance of the bitumen. The bitumen is subjected to a time sweep test or linear amplitude test in the oscillatory mode and damage in the binder is identified using dissipative energy. Here, repeated strain-controlled time sweep test was conducted and the Fourier transformation analysis was used to identify the fatigue damage of the binder. VG30 grade of the binder as per Indian specification was used and the binder was tested under long-term aged condition. The repeated oscillatory shearing was applied for 20,000 cycles of loading, and the strain amplitude used for the testing was 1.5%. The test was conducted at the temperature of 20°C and 25°C and frequency of 5 and 10 Hz. The shear stress waveform data were collected for every 50th cycle and 3rd order harmonics were determined for each cycle of loading. The evolution of ratio of I3/I1 is used to define the fatigue life. This fatigue life was compared with other conventional approaches.
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