Application of a coupled digital image correlation and discrete element method approach to model low temperature asphalt concrete fracture

The transportation industry has become increasingly focused on thermal cracking in asphalt concrete. As such, fracture tests such as a single-edge notched beam test have become the norm. The most important output from this type of test is the crack mouth opening displacement (CMOD) based fracture energy, but it only takes into account the applied load and displacement at a discrete location on the test specimen. Full field displacement evaluation such as digital image correlation (DIC) and advanced material models used in discrete element modeling (DEM) provide further avenues to characterize the complex fracture process associated with asphalt mixtures. An ongoing research study couples DEM with DIC displacement fields to study the Mode I response of asphalt concrete in the beam fracture test. Previous research studies defined local properties to match the global load-CMOD behavior using elastic contact bonds. However, improved property calibration is possible through the optimized use of DIC displacement fields and viscoelastic DEM traction-separation laws. Research findings in the proposed work demonstrate the applicability of the DIC-DEM optimization scheme.