Simplified Wedge Splitting Test for Evaluating Asphalt Low-Temperature Cracking Potential

Low-temperature cracking is a significant distress for asphalt pavements in cold climates. To evaluate the low-temperature cracking resistance of asphalt mixtures, the Semi-Circular Bending (SCB) and the Disk-shaped Compact Tension (DCT) tests are commonly used. However, both tests have their limitations. These include the relatively short ligament length and long testing duration in the SCB, and the complexity of specimen preparation associated with DCT. Moreover, both tests require low-temperature conditioning, which further increases testing time and costs. This study investigates the Simplified Wedge Splitting Test (SWST), designed to evaluate the low-temperature cracking potential of asphalt mixtures. This test aims to use gyratory compacted specimens prepared with minimal cutting effort, while ensuring a sufficient fracture ligament. It also aims to replace the low-temperature conditioning with a faster loading rate at room temperature through Time-Temperature Superposition Principle (TTSP). To this end, SWST experiments were conducted using different ligament lengths and loading rates, and a Finite Element (FE) model was developed with a cohesive zone fracture model to numerically evaluate the SWST test parameters. Experimentally determined SWST fracture properties show sensitivity to the fracture ligament length, with modeling results identifying 75 mm ligament length as optimal. FE modeling at different loading rates shows that linear viscoelasticity cannot fully capture the effect of loading rate on asphalt fracture, limiting the ability of TTSP to provide the required temperature-loading rate correlations. Thereafter, a framework with initial TTSP correction factors is proposed based on the modeling results.