Prediction of hot mix asphalt stiffness behavior by means of multiscale modeling

Abstract

Cracking behavior and fatigue performance of hot mix asphalt (HMA) are the important factors, when it comes to evaluate the durability and structural lifetime of bituminous pavement constructions. Both effects are strongly affected by resulting stresses in the bituminous layers due to traffic and/or temperature change, whereat HMA stiffness has huge impact on the magnitude of these stresses and, hence, on the durability. It is obvious that a reliable characterization and prediction of HMA stiffness is crucial. A suitable way for the description of the viscoelastic response of a material is continuum micromechanics, where the mechanical, volumetric and morphologic properties of the constituents of the material are considered to predict the homogenized, “overall” material behavior. Thereby, the material is observed on different, reasonably chosen lengths scales allowing for a description of mechanical effects where they occur. These model assumptions were validated extensively showing good accordance between experimental results obtained from 4 PB-PR tests and model predictions with only the mechanical properties of the constituents (bitumen, aggregate) and the volumetric composition as model input. The results of this investigation suggest that applying the presented technique can lead to a significant reduction of experimental efforts in mix design.