Effect of micro-scale morphological parameters on meso-scale response of Asphalt Concrete
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With recent advancement in the use of X-Ray Computed Tomography to capture the internal structure of Asphalt Concrete (AC), results have shown several possibilities to account for the distribution of the different phases in the mix and quantify them in a reliable way. The morphology of asphalt mixtures which includes the aggregate size gradation and the distribution of the air-voids and bitumen phase are captured in a single morphological parameter called the Primary Structure (PS) coating thickness-(Tps). In this study, the effect of variations in the morphological micro-structural property on the mesoscale response of three (3) AC samples is examined using the 3D Finite Element Method (FEM). The AC internal geometry is acquired using X-Ray Computed Tomography (CT); the distribution of the aggregates, mastic and air-voids phase is considered and obtained using Digital Imaging Processing (DIP) techniques. Using a surface-based cohesive behavior and assuming a predominant adhesive failure at the interface between the mastic and aggregate, a maximum traction criterion is used to obtain the damage propensity of the different mixtures. The result of the analysis shows that the microstructural morphological parameter Tps adequately captures the meso-scale response of the mixtures; there exist an inverse relationship between mixture strength characterization and the morphological parameter Tps. 2014 Taylor & Francis Group, London.