ABSTRACT
ABSTRACT: An international airport in southern Africa is experiencing premature asphalt surface distress; crescent shaped cracks appeared on the taxiway, one of the threshold areas on the runway and turning circle. Investigations into the cause and mechanism of distress indicated that delamination of the overlaid surfacing is the main cause of the crescent shaped cracks. Investigations confirmed that construction in periods of wet weather, a flat geometry and dysfunctional surface drainage coupled with an ageing porous surface layer caused stripping and delamination of the top 50 mm asphalt overlay which then showed crescent cracks due to aircraft braking and low speed turning maneuvers. A mechanistic analysis with a multilayered elastic analysis freeware was used to model the horizontal shear forces for the design aircraft with various levels of interlayer slip. The strain energy of distortion (SED) principle was used to model and predict the crescent shaped crack formation.
