OTREC-RR-10-02

The Oregon Department of Transportation (ODOT) Pavement Services Unit is in the process of implementing a new pavement design procedure being developed under the sponsorship of AASHTO. Fatigue cracking is a key distress mechanism that is predicted as part of the overall process using a theoretical model calibrated to empirical data. Tensile strain at the underside of the hot-mix asphalt pavement layers induced by truck axle loads is, in turn, a key input into the fatigue cracking model. The principal objective of the project was to assess the validity of the predicted tensile strain via layered elastic analysis. This involved collecting data from an existing test site along Interstate 5 just north of Albany, Oregon and installing and collecting data from instruments at a new test site along US 97 in Redmond, Oregon. This report documents the progress made toward achieving the principal objective of the study during the contract period (October 1, 2007 to December 31, 2008).