Finite-Element Modeling of Instrumented Flexible Pavements under Stationary Transient Loading

Abstract

Results from a finite-element program developed in the commercial code Plaxis were compared to those from an instrumented thin flexible pavement containing multiple test sections. The model has performed reasonably well under the limited environmental conditions encountered to date. Horizontal strain in the longitudinal direction of the asphalt concrete, vertical pressure in the crushed stone, and vertical pressure in the compacted subgrade were measured for 2,100 passes of loaded single axle dump truck traffic to compare to the values calculated in the model. Necessary inputs were determined using a rigorous laboratory testing program, alongside field data from over 500 drops of a falling weight deflectometer. Key features of the finite-element model include stationary transient loading and nonlinear stress dependent characterization of the compacted subgrade and crushed stone. Highlights of the results include the model moderately overpredicted unbound layer stresses, while overpredicting asphalt strain in some cases and underpredicting it in other cases, Discussion of the full scale test section, project scope, finite-element model development, and the results have been included in the body of the paper.