EVALUATION OF BACKCALCULATION ALGORITHMS THROUGH DYNAMIC MODELING OF FWD TEST.

The availability of information on pavement moduli profile is essential for mechanistic design and rehabilitation decisions of new and distressed pavements. The Falling Weight Deflectometer (FWD) test is in use by many states for monitoring variability of pavement materials and seasonal changes in material properties, and for providing data for overlay thickness design. Experience has shown that different backcalculation programs produce different results when applied to the same pavement. In this project, dynamic finite element models of flexible, rigid, and composite pavements were developed to produce deflection basins that closely match those measured during FWD tests. The pavement moduli profiles predicted by several major backcalculation programs for the same pavement structure will be compared with the moduli profile used in the finite element model. The backcalculation algorithm that produces a moduli profile closest to the one used in the model will be identified. The effect of thermal warping of concrete slabs and layers interface bond on the backcalculated moduli will be studied.