Churchill Falls Airport is located in Churchill Falls, Labrador and is owned and operated by Nalcor Energy Company. The airside pavements at the airport include Runway 13-31, Taxiway Alpha and an apron. There is relatively limited aircraft traffic at the airport. The case study presented in this paper discusses the investigation and design methodologies that were used for the rehabilitation of the runway pavement. It includes the innovative testing tools and designs that can be utilized to investigate and address challenging geotechnical and climatic conditions in remote areas in the North. The pavement at Churchill Falls airport was significantly distressed including numerous areas of frost heaving and extensive cracking. The field investigation included a detailed pavement distress inspection, test pit investigation and a geophysical survey using Ground Penetrating Radar (GPR). The field investigation program was developed based on an in depth review of findings from previous investigations. Due to the large mobilization costs for a drill rig it was decided to excavate a limited number of test pits using an on-site excavator in order to confirm subsurface soil information. Critical in ensuring the accuracy of the information obtained from the test pit investigation was the use of an experienced pavement specialist to both strategically locate the test pits in the field and prepare soils stratigraphy logs. It was determined from previous investigation and our own limited geotechnical investigation that the bedrock at the airport site was undulating and very shallow at some locations. The frost heaving of the runway pavement was due to frost susceptible subgrade soils (glacial till) and shallow undulating bedrock trapping groundwater. In order to develop a suitable rehabilitation strategy to the severity of frost heaving it was necessary to obtain a detailed map of the depth to bedrock. This mapping and continuous profile was obtained by carrying out a GPR survey. The results from the field investigations, in particular the GPR survey were used to develop pavement rehabilitation design alternatives and life cycle cost analysis to identify the most economically feasible alternative. One of the design alternatives developed included installation of polystyrene insulation to minimize frost penetration into the glacial till soils. The pavement rehabilitation was successfully completed in 2012.
Menu
