Influence of Different Interface Properties on the Interlayer Bond Shear Stiffness

Abstract

A good and durable interlayer bond is crucial for the long service life of asphalt pavements. In order to determine the shear stiffness at the interface between two asphalt layers, a new apparatus for cyclic testing of the interlayer bond (CTIB) in double-layered asphalt specimens has been developed. An extensive testing procedure has been created to take into account all the parameters that influence the interlayer bond, namely the interactions of repeated traffic loading, acceleration and braking processes as well as temperature. Numerous experimental tests have been carried out under sinusoidal repeated shear loading conditions at varying frequencies and temperatures under different normal stresses. A comparison between the average shear stiffness values at 200 g/m2, 300 g/m2 and 400 g/m2 of C60BP1-S bitumen emulsion applied on the underlying layer's surface with different degrees of contamination has been made. Furthermore, in order to examine only the effect of adhesion, without having aggregate interlocking and friction at the interface, both layer's surfaces have been finely polished before applying the tack coat at the interface.