Aggregate size distribution and hydraulic permeability of HMA: A full simulation study

Water trapped within the hot-mix asphalt layers of a flexible pavement causes the loss of strength and durability of the material, producing surface damages and deteriorations such as stripping and ravelling. Open graded pavements are considered potentially to be effective solutions to avoid these forms of infiltration-related distress. The main property that influences the performance of HMA is hydraulic permeability. The permeability is a function of several properties of HMA that make the process of mix design very complex and uncertain. In this paper, starting from different grading curves, we evaluate the dependence of the permeability by the size distribution of aggregates using a full numerical model that has yet been validated through experimental tests and theoretical calculations. The correlation between the grain size distributions and the hydraulic permeability is very useful to simplify and optimize the design of open-graded pavements.