Å·ÃÀ¿Ú±¬ÊÓƵ

Background

This research is motivated by the results of the recently completed project which recommended new moduli for the design of Full Depth Reclamation (FDR) pavements. Cold-recycling technologies, such as FDR, are effective rehabilitation strategies that reduce environmental impacts, as well as construction costs and time. FDR involves pulverizing and reusing materials from distressed pavements in place. 

FDR default values used in Pavement Mechanistic-Empirical Design (PMED) have been shown to be overly conservative. This has resulted in underestimation of performance capabilities of FDR and therefore a reluctance to implement these rehabilitation techniques. Implementing updated design values will provide a more accurate deterioration model, and allow for a representative life-cycle cost analysis (LCCA), of FDR sections. 

Research Objective

The primary objective of this research is to analyze the long-term performance and life-cycle costs of FDR compared to more traditional rehabilitation methods used by the Å·ÃÀ¿Ú±¬ÊÓƵ Department of Transportation (i.e. level and overlay or mill and overlay). To achieve this objective, the research plan considers the following sub-objectives:

• Collect long-term performance data for the CDOT Pavement Management System of FDR sections and adjacent sections which used other rehabilitation methods, as well as economic data related to construction and maintenance of these pavements. 
• Analyze the long-term performance of reference sections in terms of their roughness, cracking, and rutting, and determine the maintenance needs of the sections throughout their design life.
• Validate predicted deterioration of mechanistic-empirical models using the data available. 
• Perform a life-cycle cost analysis and conduct sensitivity analyses based on the reference sections collected. 

Research Methods

As part of this project, the research team will organize data from 11 FDR projects constructed throughout Å·ÃÀ¿Ú±¬ÊÓƵ.  The research team will also collect data on the design, construction, and actual performance of these sections from the CDOT Pavement Management System as well as pavements adjacent to the FDR sites that have used traditional rehabilitation techniques. Financial information related to the construction and maintenance of these sections will be collected as well. The research team will validate the long-term performance of these sections using the mechanistic-empirical design software (AASHTOWare). Finally, the research team will use this data to conduct a life cycle-cost analysis and sensitivity analyses that compare rehabilitation methods on the reference sections. 

Expected Findings

From the findings of this study, CDOT will have information on the relative life cycle costs of FDR materials compared to other pavement rehabilitation options. This research should benefit local entities including cities, municipalities, counties, other government agencies, consultants, and contractors that are involved in pavement rehabilitation decision-making.

Funding

Å·ÃÀ¿Ú±¬ÊÓƵ Department of Transportation (CDOT)