In-Place Stabilization for the Rehabilitation of Taxiway S at Nashville International Airport

摘要

At Nashville International Airport, Taxiway S is a parallel taxiway to Runway 2C-20C constructed in concrete and asphalt and divided in 8 different sections. The asphalt sections between Taxiway N and S5 were the most deteriorated and required rehabilitation due to the amount of distresses recorded. Distresses included load and climate related cracking, weathering and raveling. The pavement was estimated to be more than 40 years old with the last recorded mill and overlay rehabilitation conducted in 1983. The pavement investigation revealed that the asphalt sections did not have the structural capacity to carry the anticipated traffic operations. Replacement was initially considered as the only alternative since a structural overlay was not feasible due to violations to the runway's primary surface. Removing the entire pavement full-depth was an expensive alternative; therefore, other alternatives such as stabilizing the existing aggregate base to provide a stronger base over the soft clayey subgrade were considered. The initial plan was to stabilize 10 inches of aggregate base in-place to avoid exposing the underlying clayey soil. After the base was completed a 9-inch asphalt layer was to be constructed. In theory, the approach was feasible but the limited number of subcontractors in the area was a challenge. After a detailed evaluation that included life cycle cost analysis, risk assessment, sustainability and availability of contractors, the in-place stabilization of the existing aggregate base was selected. The Federal Aviation Administration P-304 specification was modified for the in-place stabilization process. This paper briefly discusses the planning, design and construction considerations conducted for the completion of this project.