Development of Probabilistic Viscoelastic Continuum Damage Model for Asphalt Concrete

The main objective of this paper is to develop a realistic probabilistic framework for characterization of different types of asphalt concrete using advanced material modeling. The adopted methodology builds on and enhances a viscoelastic continuum damage (VECD) material model by utilizing a suite of associated experimental testing protocols and incorporating the uncertainties associated with the different material properties. The modeled uncertainties address the variabilities and errors associated with the linear viscoelastic (LVE) functions achieved from the complex modulus test and damage characteristic curves obtained from constant crosshead rate testing. A probabilistic scheme using First Order approximations and Monte Carlo simulations is developed to characterize the inherent uncertainty of each of the LVE functions over the time domain of their mastercurves. For damage characteristic curves, the uncertainty in normalized pseudostiffness increases as the level of damage becomes larger. The uncertainties of LVE properties are propagated along with those of C versus stress curves to yield a probabilistic viscoelastic continuum damage model (P-VECD). The P-VECD not only predicts the average viscoelastic response to a given loading input, but it can also provide its distribution, which is essential for a reliability-based pavement design.