Reduced Rehabilitation Cost from Use of Falling Weight Deflectometer

A network-level falling weight deflectometer (FWD) testing program was performed on a selected subset, approximately 533 centerline (CL) km (330 mi), of the National Highway Network of New Jersey. The main goals of this program were to identify the limits of structurally homogeneous sections, to assess pavement structural capacity, to estimate remaining pavement service life, and to predict future rehabilitation needs. A comparison was made between the FWD rehabilitation analysis results and those obtained from the Pavement Management System (PMS) network-level rehabilitation analysis, in which network-level distress, rut depth, and roughness measurements are considered. Results of the comparison show that (a) the PMS rehabilitation analysis results agreed with those obtained from the FWD rehabilitation analysis for 27 percent (146 CL km) of the total length considered in this project; (b) the PMS rehabilitation analysis results were found to be overdesigned for 32 percent (173.5 CL km) of the total length considered in this project (e.g., the PMS selected a strengthening rehabilitation activity, whereas the FWD showed that the pavement has adequate structural capacity and no need for any structural improvement); and (c) the PMS rehabilitation analysis results were found to be underdesigned for 41 percent (224 CL km) of the total length considered in this project (e.g., the PMS analysis did not select a strengthening rehabilitation activity, whereas the FWD analysis showed that the pavement had inadequate structural capacity and there was a need for structural improvement). Limited life-cycle analysis was performed to quantify the difference between the FWD and PMS rehabilitation analysis results. In this analysis, the differences in rehabilitation costs for the overdesigned sections (173.5 CL km) and for the underdesigned sections (224 CL km) were estimated to be $6.6 million and $11.35 million, respectively.