Environmental and Economic Benefits of the Full Depth Reclamation Process in the Urban Context

In 2000, The City of Lethbridge in partnership with the “Alliance for Lethbridge Infrastructure Services (ALIS)“ consulting team commenced planning and design for the upgrading of Mayor Magrath Drive from a four-lane to a six-lane divided urban cross-section. Consideration of several pavement reconstruction alternatives led to the selection of a Full Depth Reclamation (FDR) construction strategy for the project. For this project it is estimated that approximately 25,000 cu.m. of “waste” material was reused. With conventional methods, this material would typically be removed from the site and potentially placed in a landfill. The FDR process reduced quantities of imported construction materials and resulted in an estimated 8000 less truck trips to, and from, the construction site. The FDR strategy resulted in significant capital cost savings (in the order of 28% compared to conventional reconstruction), and allowed construction to occur on a key transportation corridor within the City of Lethbridge without major disruption to traffic flow and business access. The reduction in construction duration and the environmentally responsible re-use of a non-renewable resource, were added benefits. This paper describes the process whereby the FDR alternative was selected, the steps taken to address the relative inexperience with this type of construction in Western Canada, as well as design and construction issues. The relative economics of the FDR strategy compared to conventional reconstruction alternatives are also discussed.