Backcalculation of Permanent Deformation Parameters Using Time Series Rut Data from In-Service Pavements

Abstract

Time series of rut data from 109 in-service pavement sections in the Long-Term Pavement Performance (LTPP) Special Pavement Study-1 (SPS-1) experiment were used to predict the permanent deformation parameters for the VESYS mechanistic–empirical rut model. This was accomplished by matching the rut performance curves versus time being matched for each section with a commercially available iterative solver. To ensure uniqueness of each section's permanent deformation parameters (PDPs), the transverse surface profiles were used to match the most likely contributions by layer according to the criteria proposed in the NCHRP Report 468. On average, the contribution to the total surface rutting from the various pavement layers was as follows: 57% from the asphalt concrete layer, 27% from the base layer, and 16% from the subgrade. These results confirmed that the contribution to the total rutting from asphalt concrete and base layers is important and needs to be included in any mechanistic–empirical design procedure.