Mechanism-based shift factors to predict the fatigue performance of cemented pavement materials

Cemented pavement materials (CPMs) are essential components in pavement structures, yet accurately predicting their service life due to fatigue damage remains challenging. Laboratory fatigue test results are commonly employed to predict the service life of CPMs by applying a lab-to-field shift factor (SF). However, traditional approaches rely heavily on experimental data, posing challenges in ensuring the certainty of lab-to-field results. Additionally, inconsistencies in lab-to-field fatigue failure criteria further complicate SF development. To address these challenges, this study proposes a mechanism-based methodology for developing SF. This methodology comprises a rigorous two-scale fatigue model developed by the authors to characterise the fatigue performance of CPMs at the lab scale and predict their performance at the field scale, thereby facilitating the development of SFs. These SFs are established based on a consistent lab-to-field fatigue failure criterion (i.e. the modulus reduction of CPMs). By accounting for strain differences between laboratory and field scales, SFs are derived in the strain-fatigue life space. Application of this approach to typical Australian CPMs, namely siltstone and hornfels, yields mechanism-based SFs of 1.19 and 1.21, respectively.