Development of preliminary transfer functions for performance predictions in FlexPAVE

Abstract Mechanistic-empirical design and performance-related specifications are state-of-the-art tools for designing pavements and determining incentives/disincentives for paving contracts. These methods require the reliable prediction of pavement performance throughout the pavement’s design life. One such prediction program is FlexPAVE™, which applies three-dimensional viscoelastic finite element analysis with moving loads to calculate the pavement’s mechanical responses under traffic loading and given climate data. The simplified viscoelastic continuum damage model and shift model are used to calculate the fatigue damage in the pavement’s cross-section and the rut depths, respectively. With regard to fatigue damage, a fatigue transfer function is needed to convert the computed cross-sectional damaged area (i.e., the damage level) to the cracked area on the pavement surface. With regard to rut depth, a rutting transfer function is needed to calibrate the predicted rut depths. In this study, preliminary transfer functions for the predicted fatigue damage and rut depths were developed using four sets of field measurement data obtained from test sections in the United States, Canada, and South Korea that include interstate highways and an accelerated testing facility. Good agreement between the predicted performance and field observations was found after calibration of FlexPAVE™.