Comparative Analyses of Granular Pavement Moduli Measured from Lightweight Deflectometer and Miniaturized Pressuremeter Tests

A field investigation was conducted with two testing devices, the miniaturized pressuremeter test (MPMT) and a lightweight deflectometer (LWD), to evaluate the elastic characteristics of granular pavement layers. The stress–strain data from the MPMT tests were used to determine the stiffness of pavement materials under the influence of static loading conditions in initial elastic modulus (E_i) and reload elastic modulus (E_r). The time–deflection data from the LWD tests were used to determine the stiffness parameters of pavement materials under the influence of dynamic loading conditions in dynamic deformation modulus (E_d) and LWD plate deflection. The results of the MPMT tests were compared with the results of the LWD tests in two phases. First, a direct approach was conducted with statistical analysis. MPMT elastic moduli were compared with LWD dynamic moduli. The results indicate that E_i and E_r could be used to estimate E_d. The initial-modulus model had the best prediction for granular pavement dynamic moduli, followed by the reload moduli model. Second, an inverse approach was achieved by implementing finite element analysis. Three MPMT modulus models were utilized as inputs in the two-dimensional finite element simulation to predict pavement layer deflections. The predicted deflections were compared with deflections measured from LWD tests. The results revealed that a strain-level model in numerical simulation of base course moduli provided satisfactory values of predicted deflection and that the reload modulus model yielded the best prediction deflections for subgrade soils.