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The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


Network-level Pavement Evaluation of Virginia's Interstate System Using the Falling Weight Deflectometer
Brian K. Diefenderfer
Brian K. Diefenderfer
Year: 2008
VTRC No.: 08-R18
Abstract: The Virginia Department of Transportation (VDOT) currently uses the results of automated surface distress surveys to assist in developing pavement maintenance strategies for its interstate and primary roadways. Totaling nearly 27,000 lane-miles, these roadways consist of flexible, rigid, and composite (flexible over rigid) pavements. These video-based surface distress data consist of quantities of distress that is visible in the pavement surface; however, no information regarding the actual structural capacity of the pavement system on a network level is currently available. This study describes the processes and presents the results of a network-level survey conducted on Virginia's interstate system using the falling weight deflectometer (FWD). The data obtained from this study can be used by pavement engineers to determine the structural capacity of the interstate network and to develop condition forecasting tools to assist with determining future structural conditions. Similar network surveys have been performed by the Kansas, Texas, New Jersey, Indiana, and Oklahoma departments of transportation. Although it is not yet possible to assign a monetary benefit to the results of this study as these data were not previously available, their benefits to VDOT's Asset Management Division are expected to be great. The use of these data can result in more cost-effective decisions regarding pavement rehabilitation. In a study comparing pavement rehabilitation designs based on visually observable distresses versus pavement rehabilitation designs based on structural capacity using the FWD for sections of interstate pavement in New Jersey, the authors estimated that only 27% of the designs based on visually observable distresses agreed with those based on structural data; 41% of the rehabilitation treatments were underdesigned, and 32% were overdesigned. The current study recommends that VDOT continue network-level structural evaluation of the interstate system using the FWD and perform similar testing on the primary network.