Developing Temperature-Induced Fatigue Model of Asphalt Concrete for Better Prediction of Alligator Cracking

Currently, the fatigue performance of asphalt concrete (AC) is predicted according to repeated traffic-induced tensile strain at the bottom of AC layer. Cyclic thermal strain caused by day-night temperature fluctuation is not considered because of the fact that there is no closed-form solution or model available for calculating thermal fatigue damage. This study, for the first time, develops a closed-form equation for calculating the temperature-induced fatigue damage of AC. To generate data, beam fatigue testing was conducted on three Superpave mixtures in the laboratory. The mechanical beam fatigue test data were correlated with the actual cyclic temperature loading test data. The developed model was then calibrated for field condition. Finally, the model was used to evaluate fatigue damages of randomly chosen 34 long-term pavement performance (LTPP) test sections from 19 states in the United States. Fatigue damage determined by the traditional pavement design software (which considers traffic-induced fatigue damage only) is compared with that by the combined traffic- and temperature-induced fatigue. The results show that the error may decrease by 14% through the incorporation of temperature-induced fatigue damage in the current design approach. Therefore, it is suggested to include the temperature-induced fatigue damage in the pavement design software.