Neural Networks Analysis of Airfield Pavement Heavy Weight Deflectometer Data

The Heavy Weight Deflectometer (HWD) test is one of the most widely used tests for assessing the structural integrity of airport pavements in a non-destructive manner. The elastic moduli of the individual pavement layers predicted from the HWD deflection measurements through inverse engineering analysis are effective indicators of pavement layer condition. The primary objective of this study was to develop a tool for backcalculating non-linear pavement layer moduli from HWD data using Artificial Neural Networks (ANN) for rapid structural evaluation of airfield pavements. A multilayer, feed-forward backpropagation ANN which uses an error-backpropagation algorithm was trained to approximate the HWD backcalculation function. The synthetic database generated using an axisymmetric pavement finite-element program was used to train the ANN. Using the ANN, the Asphalt Concrete (AC) moduli and subgrade moduli were successfully predicted. Apart from the moduli, an attempt was made to predict the critical pavement structural responses using ANN models. The final product was used in backcalculating pavement layer moduli and predicting subgrade deviator stresses from actual field data acquired at the Federal Aviation Administration’s National Airport Pavement Test Facility (NAPTF).