Falling Weight Deflectometer Joint Load Tests Used for Direct Calculation of Pavement Joint Stiffness

Abstract

A load test performed with a falling weight deflectometer over a joint or crack was used in a new method for the direct calculation of the apparent vertical shear stiffness of a pavement joint or crack feature (i.e., joint stiffness). Joint stiffness is the primary input parameter, or constant, in most software for the structural analysis of pavements by the finite element method (FEM) used for controlling how much load is transferred through joints between simulated concrete slabs. FAA has been developing multislab FEM analysis tools for rigid pavement. Joint models used in FEM analysis tools for pavements must be calibrated to reproduce real measured joint behaviors. The new procedure for calculation of joint stiffness based on the falling weight deflectometer enables these calibrations. This technique was used as part of a procedure for mechanistic site evaluations performed at airfield sites of heavy-duty rigid pavements as part of a study within the Innovative Pavement Research Foundation program in cooperation with FAA.