Simulation of Flexible Pavement Response to FWD Loads: A Mechanistic Approach

Pavement deflection data coupled with backcalculation analysis are widely used to estimate the layer moduli of pavement structures for rehabilitation design and for pavement asset management. This paper presents a mechanistic approach to simulate full-depth flexible pavement responses when subjected to falling weight deflectometer (FWD) loads. The FWD testing is conducted at pavement locations instrumented with strain gauges, pressure cells, and thermocouples. For the selected full-depth asphalt concrete (AC) pavement structure, layer moduli are first backcalculated from FWD data, assuming that the AC and subbase materials are linear elastic, and that the subgrade can be treated as a nonlinear elastic material. The backcalculated AC moduli are compared to laboratory values, adjusted for load duration and temperature. The adjusted laboratory values for the surface layers are consistently lower, averaging about 70 percent of the backcalculated values. The adjusted laboratory values for the bituminous concrete base course (BCBC) are about 10 percent higher than the backcalculated values. The backcalculated layer moduli are then employed to predict horizontal strains in bound materials and vertical stresses in unbound materials through three-dimensional (3-D) finite element simulations. Finally, simulated responses and pavement responses from embedded instrumentation devices during the FWD loading are compared. An average prediction error of 30 percent was found through comparison of the simulated and measured pavement responses, with the predicted responses exceeding the measured responses in every case.

並列關鍵字

Backcalculation ； Finite element method ； Flexible pavement ； FWD ； Instrumentation ； Pavement response

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