Investigation of Parameters Interface of Asphaltic Concrete and Sand

Asphaltic concrete has been used as waterproofing core in embankment dams, since 1948. The large majority of embankment dams' central core is made of clay worldwide. However, as clay is increasingly difficult to find at new construction sites, asphalt concrete was used as a replacement core material. Cores made of clay has also some other disadvantages such as, low shear strength, compressibility, long construction time, requiring higher amount of material and accurate controls during construction, etc. These are in favor of using asphalt concrete, which has advantages such as less sensitivity to weather conditions, less width of core, healing behavior of bitumen, high shear strength etc. In this application, granular materials are used around the asphaltic concrete as filter, which makes a complicated behavior in the interface and needs to be researched by experiments and modeling. This paper describes experimental work and the results of investigating the mechanical behavior of the interface between aggregates and asphaltic concrete. Small scale shear strength test has been used in this study, in which the shear surface is considered as the interface. The effect of bitumen penetration grade, moisture, density and angularity of aggregates on the shear strength parameters at different levels of vertical stresses and a constant shear rate was studied.