In order to determine the shear stiffness at the interface between asphalt layers and to take into account the interactions of repeated traffic loading, acceleration and braking processes as well as temperature influence, a complicated apparatus for cycling testing of the interlayer bond (CTIB) has been developed. An extensive experimental procedure has been created to include all factors that influence the interlayer bond. Using the experimental results, a master function for the analytical assessment of the shear stiffness has been established. The regression which approximates most accurately the experimentally determined shear stiffness values is the sigmoid function. Through implementation of the master function into a finite element program the fatigue status of asphalt pavements, which is affected by the interlayer bond of different quality, have been calculated over the service life of 30 years using the German method for computational design according to RDO Asphalt 09. The results presented below are based on the results of IGF project “Cyclic Shear Stiffness and Shear Fatigue Testing for Evaluation and Optimization of Interlayer Bond in Asphalt Pavements”, supported by the Association of Industrial Research Communities (AIF) of the German Asphalt Institute (DAI) in cooperation with TU Braunschweig.
Monetary evaluation of the reduced service life of asphalt pavements caused by the interlayer bond
