Implementation of the Linear Amplitude Sweep Test to Evaluate Fatigue Resistance of Highly Polymerized Asphalt Binders

Highly polymerized asphalt binders (HPABs) such as PG 64-40 have been increasingly used in cold regions such as Alaska in recent years. However, there are currently considerable data gaps when it comes to the characterizations of the HPABs, especially their fatigue behaviors. The objective of this study is to apply the linear amplitude sweep (LAS) test with the viscoelastic continuum damage (VECD) model to assess the fatigue resistance of HPABs. Three HPABs (PG 52-40, PG 64-40, and PG 52-46) and one unmodified binder (PG 52-28) were used in the study. The fatigue failure during LAS tests on HPABs was defined, and an analysis protocol using the VECD model was proposed based on the experimental results. The analysis protocol was validated by the agreements of the predicted and measured number of cycles to failure in the time sweep (TS) test. The results indicated that the LAS test with the selected analysis protocol can effectively predict the fatigue lives of HPABs. Both the LAS and TS test results showed that the HPABs had higher fatigue resistance than the unmodified asphalt binder. Among the four binders, the PG 64-40 binder exhibited the longest fatigue lives under repeated loadings.