Development Of A Comprehensive Backcalculation Procedure For Rigid Pavement Design Parameters Using Slab-Edge Deflection Basins

Abstract

Backcalculation of structural parameters for rigid pavements is commonly conducted with falling weight deflectometer (FWD) deflection basins measured at the center of slabs. Although a number of established techniques exist to backcalculate pavement parameters for the slab-center location, a reliable technique to backcalculate such parameters at the neighboring slab-edge location does not exist. The slab-edge location is critical to the design and management of rigid, concrete pavements because high stress levels and early signs of degradation originate at the slab edge. An edge backcalculation procedure accounting for the load transfer efficiency (LTE) of inter-slab joints is developed in this study. The proposed procedure is based on finite element modeling and dimensional analysis. Testing and validation of the edge backcalculation procedure is performed using FWD basins measured at the slab-edge location of in-situ pavements, along with measured LTEs, via the Long Term Pavement Performance (LTPP) program. Some prospective applications of the new procedure, in conjunction with the LTPP database, are presented. It is shown that the new edge backcalculation procedure is robust and satisfactory, particularly for pavements in good structural condition.