An accurate assessment of the fatigue life of hot mix asphalt (HMA) mixtures depends on the criteria used in the fatigue analysis.\r\nIn the past, various studies have been conducted on crack initiation and crack propagation of the HMA mixtures. Most of these\r\nstudies were focused on the beam samples with or without a sawed crack at the bottom. ?is paper presents and discusses two\r\ndifferent fatigue life criteria for two-dimensional problems represented by cylindrical samples. One criterion is based on the rate\r\nof accumulation of the tensile horizontal plastic deformation (HPD) as a function of the number of load repetitions. ?e second\r\ncriterion is based on fracture mechanics, stress intensity factor, and the rate of crack growth with respect to the number of load\r\nrepetitions. It was found that, because of three-dimensional nature of the crack growth in cylindrical samples, the Paris� law was\r\nviolated. It is shown that the rate of crack growth criterion provides higher values of fatigue life relative to the rate of accumulation\r\nof HPD criterion. Although a trend could be established among the fatigue lives obtained by using the two criteria, it was found\r\nthat the fatigue lives obtained from the rate of accumulation of HPD were consistent and based on the actual measurement of HPD\r\nfor HMA mixtures.
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