Experimental Investigation of the Mechanical Behaviour of Interfaces Between Pavement Layers

Pavement structure lifetime can be dramatically reduced in case of poor bonding between layers. Study of interfaces between pavement layers is essential to improve pavement durability. An innovative and new experiment named 2T3C Hollow Cylinder Apparatus (2T3C HCA) has been implemented to characterize interface performances. In this test, combined compressive (or tensile) stress and shear stress can be independently applied to the interface. The tested samples are hollow cylinder samples (12 cm height, 17.5 cm external diameter and 12.5 cm internal diameter) constituted of two bituminous pavement layers separated by an interface made with a tack coat. Samples representing a pavement structure are made in laboratory using the French wheel compactor. Digital Image Correlation (DIC) is used to obtain displacements in the three dimensions on the surface of samples. It makes it possible to locate the interface and observe its deformation. In this paper the 2T3C HCA device is presented and first results on bituminous mixtures behaviour and on interface behaviour are presented.