Investigation of energy-based crack initiation threshold from meso-scale asphalt concrete response

Abstract

The existence of a fundamental energy threshold for meso-scale crack initiation is investigated using micromechanical modeling techniques. X-ray Computed Tomography (CT) is used to acquire the internal structure of an asphalt concrete mixture while Digital Image Processing (DIP) techniques is used to segment and analyze the different phases present in the mixture. Finite Element (FE) modeling is used to simulate a tensile loading condition to establish a critical micromechanical criterion for meso-scale crack initiation. The meso-scale asphalt concrete mixture is subjected to different loading rates to obtain the global strain energy density at the instance when the critical micromechanical crack-initiation criterion threshold is attained at different deformation rates. The result from the study shows that there exists a fundamental global strain energy density threshold that is invariant of the rate of loading at the instance of meso-scale crack initiation. The result of this study also shows the potential of the use of X-Ray computed tomography in understanding the cracking phenomenon in asphalt mixtures.