TA256 : Evaluating the fracture resistance of core baxsed asphalt samples using semi-circular bending test
Thesis > Central Library of Shahrood University > Civil & Architectural Engineering > MSc > 2015
Authors:
Abstarct: Cracking of hot mix asphalt (HMA) pavements at low temperature condition is one of the most common HMA pavements`distresses that leads to the reduction of ride quality and the long-term durability of pavement. The traffic loading and weather cycles causes tensile stresses at the bottom of asphalt laxyer and the repetition of these factors lead to the initiation and propagation of cracks at the asphalt pavement. Thus, it is important and necessary to have the precise and accurate knowledge of the behavior of binder and asphalt mix at low temperature, and determining the causes and mechanisms of its cracking. Due to the viscoelastic nature of asphalt, various factors including temperature and loading time will have a significant impact on the asphalt behavior. In this study, in order to examine the asphalt cracking resistance at -15 ˚C, under mode I loading, semi-circular bending test (SCB) has been used. Fracture parameters including stress intensity factor, fracture energy and the critical value of strain energy release rate were determined for asphalt samples. In the first section of this study, to evaluate the effects of asphalt aging on its cracking resistance, three asphalt samples with same conditions (in terms of mix design, traffic loading volume and weather conditions), and with three different service life of zero, two and six years were prepared through pavement coring. In the second section of laboratory work and in order to examine the effect of loading speed on fracture parameters of semi-circular asphalt samples with the service life of two years, the semi-circular bending test with two different speeds was conducted (5 and 50mm/min). Evaluating the diagrams obtained from tests showed that asphalt behavior at -15 ˚C is quite linear. According to test results, by increasing the pavement life, breaking deformation and fracture energy of samples significantly reduced. By increasing the pavement life, the critical value of strain energy release rate (which is called J integral) reduced. baxsed on test results, by increasing loading speed, failure force of samples increased and fracture energy and breaking deformation reduced. Finally extended finite element modelling of crack propagation using linear elastic fracture mechanic approach was done according to the experimental test results.
Keywords:
#Extended finite element method #Fracture parameters #Low temperature asphalt cracking #Semi-circular bending test Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: