Pavement Structural Evaluation: Production Level FWD Back-Analysis Using the Full Time History

When pavement structural evaluation is carried out using the Falling Weight Deflectometer, the full displacement-time history for each geophone is measured in the field, but for normal production only the peak deflection data are stored for subsequent processing. Velocity and acceleration information can however be readily captured. A preliminary study has been made to examine whether useful time-dependent parameters could be extracted from the full time history and used by practitioners. Software has been developed for capturing wave speeds and correlating with approximate moduli of the surface layer, to complement conventional back-analyses. Surface wave speeds appear promising indicators to allow rapid distinction of near surface material types and structural condition, at no additional cost or time. For the covering abstract see ITRD E118503.