Evaluation of fatigue endurance limit of dense bituminous mix using different failure theories for the design of perpetual pavement

The endurance limit of the bituminous mix is an important parameter in the mechanistic-empirical based pavement design concept. Dense bituminous macadam (DBM) is one of the most used bituminous mixes in the binder course of pavement construction. This research aims to evaluate the fatigue endurance limit of the dense bituminous mix using beam fatigue tests. In the beam fatigue test, samples, composed of DBM gradation type II and Polymer modified bitumen of grade 40 (PMB-40) binder, were tested under strain conditions: 600 & mu;& epsilon;, 400 & mu;& epsilon;, 300 & mu;& epsilon;, 200 & mu;& epsilon;. Further, the number of repetitions until failure was estimated using logarithmic regression and single-stage Weibull function method for those which did not fail after 10 million cycles. The endurance limit was determined from the analysis of the graph plotted between strain values and the number of repetitions/cycles until failure. The logarithmic regression method showed better results for fatigue life, compared to the single-stage Weibull method. The mixture of DBM-II graded aggregates and PMB-40 binders could be used in the pavement construction for longer design life. Finally, the laboratory determined Endurance limit is used in pavement design and is presented through a representative case.