Who
Department of Public Works
Where
Chattanooga, TN
When
November-December 2007
What
Full-Depth Reclamation with Cement Stabilization
Why
"To extend available resources, the city is evaluating and implementing the use of innovative materials and methods to extend the service lives of existing pavements and push the design lives for new projects from 20 years to 30 to 50 years."
Author(s)
Ariel Soriano, Government Engineering
Chattanooga, TN, has over 1,200 centerline miles of roadway and numerous paved areas to manage. Like many municipalities in the United States, Chattanooga maintains and rehabilitates this massive infrastructure with limited resources and funding. To extend available resources, the city is evaluating and implementing the use of innovative materials and methods to extend the service lives of existing pavements and push the design lives for new projects from 20 years to 30 to 50 years. Two methodologies evaluated and implemented by Chattanooga are full-depth reclamation (FDR) and FDR with cement stabilization (FDRC).
FDR and FDRC both use a pavement reclaimer to pulverize the existing pavement structure to some predetermined depth. The reclaimed material, which normally requires some water addition to bring the material up to its optimum moisture content, is then graded and compacted in-place to form a new aggregate base or subbase as part of a new pavement structure. FDRC involves incorporating three to five percent (by weight) Type I portland cement and water with the pulverized material into a relatively consistent mixture. The resulting material may then be graded and compacted in place to form a new stabilized base or subbase for the new pavement structure. In both cases, hauling away existing material and exposing the subgrade to potential precipitation is minimized or eliminated.