Developing a Network-Level Structural Capacity Index for Asphalt Pavements

This paper presents a network-level structural capacity indicator for asphalt pavements in the state of Virginia. A literature review revealed that several network-level structural capacity indexes have been proposed, and a number of states use structural capacity measures in their network-level decision processes. Some decision methods and structural indexes are compared in this paper using network-level deflection data collected using the falling weight deflectometer and distress data from tests conducted on Virginia interstates. One index that is based on the structural number concept, the Structural Capacity Index, is found to produce network-level decisions that most closely match project-level work done by the Virginia Department of Transportation during the 2008 construction season. The index was adopted, and its sensitivity to various input parameters was determined. Furthermore, the impact of the structural capacity of the pavement on the service life of a pavement maintenance treatment was clearly established in this paper. Equations to define the service life of a corrective maintenance treatment as a function of the structural condition of the pavement are also presented in this paper.