Calibration of Fatigue Transfer Functions for Mechanistic-Empirical Flexible Pavement Design

Abstract

As agencies continue to adopt mechanistic-empirical (M-E) pavement design, the need for locally calibrated transfer functions will continue to increase. Transfer functions are the critical link from mechanical pavement response to field performance. Further, the models must be applicable to the given field conditions and local materials. To that end, fatigue transfer functions were developed using data from the 2003 Structural Study at the National Center for Asphalt Technology (NCAT) Test Track. This included in situ material properties, performance data, traffic data along with environmental and dynamic response data via embedded instrumentation. Fatigue transfer functions were developed using exclusively field data. In order to develop the models from the field data, an extensive testing scheme and parameter characterization process was developed. In addition, a data acquisition and processing procedure was developed to handle the dynamic strain data. From this studying, no comprehensive conclusions could be made regarding the fatigue performance of the two binders tested: neat PG 67-22 and polymer-modified PG 76-22 because only three test sections showed significant fatigue distress at the time of this thesis. Of the two complimentary sections that did reach fatigue failure, the PG 67-22 showed slightly better fatigue performance. Further, the rich bottom test section with neat binder did not perform as well in fatigue as the other conventional cross sections. In addition, it was determined that three separate fatigue models were needed to describe the fatigue performance: a thin, thick and rich bottom model.