Deflection-Based Analysis Techniques for Jointed Concrete Pavement Systems

Techniques are presented that are based on the dense-liquid foundation model for analyzing deflection data obtained at center slab, slab edge, and slab corner positions to provide indications of the quality and uniformity of support beneath jointed concrete slabs. Deflections obtained at central slab positions are used to quantify a baseline foundation k-value for each slab tested. Edge and corner deflection data are used to establish the foundation edge and corner k-values of each slab. Adjustments for slab size and temperature curling during testing are discussed. Slab support ratios are determined on a slab-by-slab basis using the ratio of edge and corner k-values to center-of-slab k-values, k_e/k_i, and k_e/k_i. When nonuniform support exists, the foundation support ratio will typically be less than 0.75. Example and field results are provided to illustrate the analysis techniques and the interpretations necessary to distinguish between poor support due to slab curling or foundation voids.