Runway Pavement Rehabilitation Design and Construction in Remote Areas in the North-Case Study

This paper discusses the unique challenges that can be encountered during the design and construction of airfield pavements in remote areas and under harsh climatic and soil conditions in the North. The case study will identify the problems encountered and the solutions that were implemented or recommended to overcome these issues. The case study is about the Runway 13-31 pavement major rehabilitation at Churchill Falls Airport in Labrador. The airport is located in a very remote area with very limited access to paving materials and contractors. In addition to the remoteness of the airport, it also experiences harsh winters and a frost penetration depth of approximately 3.0 m below the ground surface. Subgrade soils at the airport are comprised of a frost-susceptible glacial till underlain by a shallow, undulating bedrock. Extensive Ground Penetrating Radar (GPR) survey was carried out to map the depth to bedrock. The primary distresses on the runway pavement were extensive frost heaving and cracking. The shallow bedrock was also a significant challenge that had to be considered in selecting feasible rehabilitation alternatives. Five pavement design alternatives were considered: (1) reconstruction without grade raise; (2) reconstruction with 0.5 m grade raise; (3) rehabilitation, including pulverizing existing pavement; (4) rehabilitation, including installation of polystyrene insulation (5) pavement rehabilitation without grade raise. Drainage improvements included deepening an intercepting ditch and construction of new subdrains along both edges of the runway. Subdrains design included very extensive rock cuts. Although the Life Cycle Cost Analysis indicated that the most cost effective was Option 2, the Client decided to go ahead with Option 5 which had the lowest initial cost. Major construction issues included difficulties with obtaining good quality aggregates and proper asphalt cement grade, asphalt mix production in very remote location, deep rock cuts and difficult soil and weather conditions.