Modeling Interface Debonding between Asphalt Layers under Dynamic Aircraft Loading

Understanding and avoiding debonding failures is extremely important as the only repair is removal and replacement, which is very costly and time consuming. However, mechanical modeling of interface layer slippage is complex, requiring advance modeling techniques, commonly resulting in the assumption of full bonding in modeling pavement response to loading. A case study is presented analyzing a debonding failure at one of the nation’s busiest international airports. For this high risk situation the newly developed 3D-FAST (3-dimensional Fourier analysis of pavement structures under transient loading) software was used. It was selected because it is capable of analyzing pavement under dynamic loading with visco-elastic material characterization. 3D-FAST is also capable of analyzing pavement responses under fully bonded and partially bonded conditions at layer interfaces. Furthermore, it has been verified using rheological models, as well as has been validated using several case studies. Heavy aircraft dynamic loads under take-off, taxi and landing conditions were simulated and analyzed using 3D-FAST. In the analyses, layers were considered fully bonded, however, as shear stress exceeded the critical value a slippage factor was used to address interface shear transfer characteristics. The results of this case example illustrate the contribution of debonding to airfield pavement service life. It also illustrates the use of a powerful analytical model for estimating airfield and highway pavement responses under dynamic loading available in the public domain.