Unsteady flow simulation of water drainage in open-graded asphalt mixtures

Laboratory tests or measures on the field are widely carried out in order to evaluate the drainage capability of pavement. Such an approach is in general not efficient and it shows poor significance. In this paper we propose a novel method, very effective for mix design, based on simulation of unsteady-flow of water through open-graded mixture. In particular we have modelled internal microstructures of an open-graded asphalt sample, positioning any aggregate particle and creating the bitumen film around each of them. The unsteady-flow of water inside the sample is simulated to evaluate the expected permeability for different specimens and compaction