Top-Down Cracking Prediction Tool for Hot Mix Asphalt Pavements

This paper presents an analysis tool for predicting top-down cracking (TDC) of hot-mix asphalt (HMA) pavements. TDC is known to involve a complicated set of interactive mechanisms, perhaps more so than other HMA distresses. Such complexity makes it difficult to predict TDC reliably using conventional material models and analysis tools. Over the years, the viscoelastoplastic continuum damage (VEPCD) model has been improved to better understand and predict the behavior of asphalt concrete materials. The ability of the VEPCD model to accurately capture various critical phenomena has been demonstrated. For fatigue cracking evaluation of pavement structures, the viscoelastic continuum damage (VECD) model has been incorporated into a finite element code as VECD-FEP++. To use this code in the prediction of TDC requires the enhancement and incorporation of additional sub-models to account for the effects of aging, healing, thermal stress, viscoplasticity and mode of loading. The Enhanced Integrated Climatic Model (EICM) is also integrated into the framework.The flexible nature of the VECD-FEP++ modeling technique allows cracks to initiate and propagate wherever the fundamental material law suggests. As a result, much more realistic and accurate cracking simulations can be accomplished using the VECD-FEP++.To demonstrate the full capabilities of the VECD-FEP++, two example simulations were carried out, and the results indicate that the interactions among the sub-models and overall trends in terms of pavement behavior were reasonably captured.After proper calibration, this tool could provide quantitative predictions of the extent and severity of TDC.