RESEARCH TO IDENTIFY ADVANCED ASPHALT TECHNOLOGY TO ADDRESS SHEAR DISTRESSES ON AIRSIDE FACILITIES

Taking in to account the widespread application of asphalt pavements for airside infrastructure and the very high shear forces at airport pavements, it is critical that these forces and their affect are carefully considered during the design and construction phase of asphalt materials. This paper describes an ongoing research on shear distresses at airside facilities focused on identifying the primary factors in the pavement design and construction phases that affect the development of these distresses in the asphalt layers in airport pavements and how to address them. Distresses related to application of high shear forces is one of major concerns associated with airfield pavements and has been observed at airports of varying sizes and in varying climates. The recent few examples are Lester B. Pearson International Airport in Toronto, Edmonton International Airport, Halifax International Airport and Quebec International Airport. These particular distressed areas may pose a significant safety hazard and are a challenge for airport operators as well as a continuous economic burden to both airport operators as well as airlines. Due to the complexity of the issue, the current pavement technology does not address it efficiently but rather focuses on short term repairs of the problems areas. In spite of best practices in pavement structural design and construction being followed, distresses that are consistent with existence of very high horizontal and shear forces frequently occur at certain, critical locations on airside pavements (stop bars, sharp turns, rapid exits). These distresses appear to be occurring in spite of the pavement and asphalt mix being structurally adequate to accommodate vertical loads. The research goal is to identify the flexible pavement failure mechanism at high shear areas and through laboratory testing and finite element modelling to identify asphalt mix and other material adjustments that can be made to achieve pavements with sufficient shear resistance. The behaviour of the asphalt materials is being modeled using finite element methodology to evaluate its response to applied shear stresses. The model is then used to evaluate the effect of asphalt mix and materials characteristics on the shear resistance of airfield asphalt mixtures. Finally, a test or tests is being identified that can be used to evaluate the suitability of candidate asphalt mixtures based on their resistance to development of shear distress.