Evaluation of fatigue endurance limit of dense bituminous mix using different failure theories for the design of perpetu
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International Journal of Pavement Research and Technology Journal homepage: www.springer.com/42947
Evaluation of fatigue endurance limit of dense bituminous mix using different failure theories for the design of perpetual pavement Sanchit Ananda,b*, Arun Gaurb, Gagandeep Singhc b
a Department of Civil Engineering, Manipal University Jaipur, Jaipur 303007, Rajasthan, India Department of Civil Engineering, Malaviya National Institute of Technology Jaipur, Jaipur 302017, Rajasthan, India c Central Road Research Institute, New Delhi 110025, India
Received 31 January 2020; received in revised form 30 July 2020; accepted 17 August 2020
Abstract
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 rese arch 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 grad ation type II and Polymer modified bitumen of grade 40 (PMB-40) binder, were tested under strain conditions: 600 µε, 400 µε, 300 µε, 200 µε. 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 li mit is used in pavement design and is presented through a representative case. Keywords: Endurance limit; Beam fatigue test; Dense bituminous mix; Perpetual pavement; Hot mix asphalt
1. Introduction The concept of endurance limit, the maximum strain level below which fatigue damage never occurs was originally developed for metals [1,2]. It is also recognized as fatigue stress, the maximum stress that a material can withstand for an infinite number of cycles without causing fatigue failure [1]. In stress versus cycles to failure plot, therefore, the limit becomes essential to be horizontal and fatigue-free. In literature, for asphalt pavements, the endurance limit for bituminous mixes was proposed as 70 µε, since in log-log relationship, the plot between strain and fatigue cycles converged at approximately 70 µε and approximately 5 million cycles [3]. A pavement often experiences fatigue strain due to vehicle repetitions and thus, the endurance level would be the maximum strain level that it can withstand without fatigue failure, * Corresponding author E-mail address: [email protected] (S. Anand); [email protected] (A. Gaur); [email protected] (G. Singh). Peer review under responsibility o
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