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Abstract. In this paper, detailed study is carried out to develop a new workflow from image acquisition to numerical simulation for the asphalt concrete microstructures. High resolution computed tomography scanned images are acquired and the image quality is improved using digital image processing techniques. Nonuniform illumination is corrected by applying an illumination profile to correct the background and flat-fields in the image. Distance map based watershed segmentation are used to segment the phases and separate the aggregates. Quantitative analysis of the micro-structure is used to determine the phase volumetric relationship and aggregates characteristics. The result of the quantitative analysis showed a very high level of reliability. Finite Element simulations were carried out with the developed micro-mechanical meshes to capture the strength and deformation mechanisms of the asphalt concrete micro-structure. From the micro-mechanical investigation the load transfer chains, higher strength characteristics and high stress localization at the mastic interface between adjacent aggregates was shown.

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Short-term aging of asphalt binders is an inevitable phenomenon during mix production and laydown that significantly affects the rheological properties of asphalt binders and further contributes to the deterioration of pavement performance. This paper presents a new short-term aging model for asphalt binders. The new model focuses on the binder viscosity as the target property and incorporates the rheological activation energy for the model development. It consists of four model coefficients and two essential binder specific inputs (i.e. viscosity and rheological activation energy of the unaged asphalt binder). The rheological activation energy is calculated from the conventional properties of unaged asphalt binders like penetration, kinematic viscosity, and absolute viscosity measured at various temperatures or from the known Viscosity Temperature Susceptibility parameters (i.e. ''A-VTS'' values) of unaged asphalt binders. The global model coefficients are determined using data extracted from the longterm pavement performance database. The short-term aging is verified to increase the rheological activation energy of the asphalt binder to a certain amount which is linearly proportional to that of the unaged binder. It is also found that the new model delivers more accurate viscosity prediction capabilities over the existing binder aging model. The new model is then validated through data collected from multiple independent data sources. The validation results indicate that the new model provides fairly accurate predictions in both laboratory and field short-term aging. Thus, it can be concluded that the new model is a good candidate for the short-term aging prediction. Keywords Short-term aging Á Viscosity Á Rheological activation energy Á Asphalt binder 1 Introduction Aging is a phenomenon that affects the physical properties, rheological properties as well as the Electronic supplementary material The online version of this article (