Development of a Fatigue Life Prediction Model for Rejuvenated Recycled Asphalt Binders under Various Thermal Conditions

Abstract

The Linear Amplitude Sweep (LAS) test is recognized as a valuable tool for evaluating the fatigue performance of asphalt binders. However, due to their viscoelastic behavior, fatigue life is highly temperature-dependent. Therefore, selecting an appropriate testing temperature for LAS remains a critical challenge. This study investigates the combined effects of temperature and strain at intermediate temperatures using LAS tests conducted at four different temperatures on rejuvenated recycled asphalt binders. A simplified approach is proposed to predict fatigue behavior at various temperatures using limited experimental data. The results show that LAS parameters (A and B) exhibit linear correlations with the complex modulus (|G*|) at the corresponding temperatures. Model parameters were calibrated using experimental data at two temperatures to predict fatigue life at other temperatures. Based on the maximum stress failure criterion and a 35% damage level recommended by AASHTO, the proposed model provides a simple and accurate framework for fatigue life prediction over a wide range of temperatures and strain levels relevant to rejuvenated recycled binders in flexible pavements.