Evaluation of the Federal Aviation Administration methodology for characterizing the nonlinear behavior of granular base and subbase materials

While the overall average results of 243 separate pavement computer analysis were found to provide somewhat comparable modulus values, several analytical limitations were found that would lead to relative errors of resilient modulus of base and subbase materials ranging from −60% to +60%. Errors in the modulus of the underlying base and subbase layers are very important as they will lead to significant errors in predicting the subsequent fatigue cracking resistance and predictions of any asphalt surfacing layer.