Fatigue and Thermal Cracking Analysis of Asphalt Mixtures Using Continuum-Damage and Cohesive-Zone Models

Abstract

Cracking in asphalt pavements has continued to cause prominent pavement distress. This study evaluated fatigue and thermal cracking performance for nine asphalt mixtures using three approaches: simplified viscoelastic continuum-damage model; thermal stress-driven Paris-law cracking model; and cohesive-zone fracture model. The mixtures encompass three asphalt binder grades, three aggregate sizes, and a combination of recycled asphalt amounts. Simplified viscoelastic continuum-damage characterization of the mixtures was performed using direct tension cyclic tests and low-temperature fracture characterization using disk-shaped compact tension tests. Cracking performance predictions were conducted using the layered viscoelastic pavement analysis for critical distresses software, the thermal cracking model used in PavementME, and the IlliTC thermal cracking simulation systems. Various lab-measured performance prediction parameters were compared with simulation results. Analysis shows that the use of simulation models is essential to reliably link lab-measured properties with expected cracking performance of asphalt mixtures. Furthermore, the study also shows that fatigue and thermal cracking performances are not linked and the study also shows lack of correlation between cracking performance and recycled asphalt binder contents.