Use of Falling Weight Deflectometer Data for Network-Level Flexible Pavement Management

Abstract

The objectives of this research were to investigate spatial and temporal falling weight deflectometer (FWD) testing rates employed in network-level pavement management by selected state departments of transportation (DOTs) and to recommend specific methods of FWD analysis that best reflected actual pavement conditions. With funding from the Utah DOT, a literature review and a telephone questionnaire survey were performed. FWD data collected from Legacy Parkway and Long-Term Pavement Performance Program Site 49-1001 were analyzed with models by Noureldin, Hoffman, Jameson, COST (European Cooperation in Science and Technology), Rohde, and AASHTO, as well as with multiple-layer linear elastic analysis (MLLEA), which was assumed to be the most accurate of the methods evaluated in this study. In consideration of (a) the results of two-way comparisons with the MLLEA method, (b) applicability to situations in which pavement layer thicknesses are not known, and (c) simplicity, the COST method is recommended for general implementation. To the extent that the data sets analyzed in this research are representative of the Utah DOT pavement network, the COST model should be modified according to the regression results developed in this research to produce more accurate calculations of structural number. Application of temperature corrections to FWD deflections is recommended for structural pavement monitoring.