Mechanistic Assessment of Flexible Pavements in Wisconsin Using Traffic Speed Deflectometer

Abstract

The traffic speed deflectometer (TSD) has been gaining interest for pavement management practices, as it can continuously collect deflection data at traffic speed without requiring traffic control. TSD data have been typically used to provide an estimate of the structural condition of pavements with a limited range of significant parameters considered in the analysis. To date, limited studies have been conducted in or for cold regions to consider the potential use of TSD data for pavement structural assessment. This study aimed to bridge this gap by developing a twofold approach to: (1) mechanistically characterize the structural integrity and remaining life of pavements; and (2) compare TSD and falling weight deflectometer (FWD) data collected in the field, considering the features of pavement facilities in Wisconsin. A field testing plan was developed to characterize the site-specific features of eight representative pavement sections, with a total length of about 30 mi and distinct pavement structures, truck traffic patterns, and climatic conditions. The postprocessed results underscored the significance of the TSD data and their potential for the structural evaluation of underlying layers in a multilayered pavement system when integrated with the site-specific pavement profile and truck traffic information derived from field testing. A comparison of the normalized deflections and structural parameters characterized by TSD and FWD data showed similar trends, while the average FWD-based deflections were 12%–37% higher than the TSD-based deflections.