SABOURI, MOHAMMADREZA. Development of a Unified Fatigue Failure Criterion for Asphalt Mixtures and Its Applications to Reclaimed Asphalt Pavement (RAP) Mixtures

ABSTRACT SABOURI, MOHAMMADREZA. Development of a Unified Fatigue Failure Criterion for Asphalt Mixtures and Its Applications to Reclaimed Asphalt Pavement (RAP) Mixtures. (Under the direction of Dr. Y. Richard Kim.) Fatigue cracking due to repeated traffic loading is one of the major types of distress in asphalt concrete pavements. Propagation of fatigue cracks in the asphalt layer will eventually allow water to come into the pavement system, and cause deterioration of pavement structure which reduces its serviceability. Hence, description and prediction of fatigue resistance of hot mix asphalt (HMA) in an accurate manner is extremely important to flexible pavement design and preservation. In this study, to predict the fatigue life of the pavements, a failure criterion for the simplified viscoelastic continuum damage (S-VECD) model, referred to here as G R method, is proposed. This failure criterion found to exist in both reclaimed asphalt pavement (RAP) and non-RAP mixtures and also found to be independent of the mode of loading, strain/stress amplitude, and temperature and also is effective in accurately predicting the fatigue life of the mixtures. The direct tension cyclic test with the G R method, along with beam fatigue test, and overlay tester were used to evaluate the fatigue cracking performance of plant-produced RAP mixtures in the Northeast. The S-VECD model and the G R method also was input to the linear viscoelastic pavement analysis for critical distresses (LVECD) program to predict the fatigue behavior of the tested mixtures on thin and thick asphalt pavement structures. This study included testing on 12 plant-produced mixtures from New Hampshire and Vermont that contained RAP contents of 0% to 40% by total weight of mixture. In addition, the performance grades (PGs) of the binders that were extracted and recovered from the mixtures were determined. In general, the addition of RAP resulted in an increase in the stiffness of the materials. The magnitude of the impact of higher RAP percentages varied with each set of mixtures. The S-VECD model and beam fatigue test data showed a loss of fatigue resistance for high percentage RAP mixtures in most of the cases. The overlay tester results showed