Graphical solutions for back-calculation of rigid pavement parameters

This technical note presents the graphical version of the solutions of a closed-form back-calculation algorithm for two-layer rigid pavements, The development of the graphs and the theoretical basis for the choice of analysis parameters for the graphical solutions are described. Graphs are developed for back-calculating the moduli of the pavement slab and the subgrade, based on the common deflection measurement data obtainable from typical falling weight deflectometer tests. Two sets of graphs are presented, one for back-calculating the radius of relative stiffness, and the other for determining the deflection factor that relates pavement properties to surface deflections. The graphical solutions are applicable for back-calculating the properties of rigid pavements supported on either a liquid foundation or a solid foundation.