Evaluation of remaining fatigue life model for hot-mix asphalt airfield pavements

Several design criteria exist for predicting the fatigue life of hot-mix asphalt (HMA) pavements. Researchers previously developed an Aged Asphalt fatigue criterion from laboratory testing of aged field HMA airfield pavements. This criterion is unique because the majority of the existing fatigue criteria were developed from laboratory-prepared specimens. In this paper, a comparison of the Department of Defense (DoD), the Asphalt Institute (AI) and the Aged Asphalt fatigue models was completed for the HMA surfaces. The analysis showed that the Aged Asphalt fatigue criterion was more conservative than the DoD and AI fatigue criteria at low strain levels and low pavement modulus values. Furthermore, the Aged Asphalt fatigue criterion revealed that fatigue life decreased with increasing strains but increased with increasing modulus values. After evaluating the potential causes of this unexpected trend in detail, it is reasonable to expect that stiffer in situ mixes will have a longer fatigue life than less stiff mixes.