Internal stability of road aggregate grading

The drainage of road materials has a major impact on the durability of roads. This drainage capacity is intimately linked to the granulometry of the road materials which must have a certain stability to avoid that the fines are carried away by water flow. During the experimental approach we evaluated two complementary aspects of the filtration: that of the modifications to the granulometry (rearrangement of the particles) and that of the local variations of hydraulic conductivity whereas the only forces which act are limited to those of water flow and gravity. It has highlighted the unstable behavior of certain granulometric compositions.