Issue 43

M. Fakhri et alii, Frattura ed Integrità Strutturale, 43 (2018) 113-132; DOI: 10.3221/IGF-ESIS.43.09 113 The effect of loading rate on fracture energy of asphalt mixture at intermediate temperatures and under different loading modes M. Fakhri, E. Haghighat Kharrazi Department of Civil Engineering, KN.Toosi University of Technology (KNTU), Tehran, Iran M.R.M. Aliha * Welding and Joining Research Center, School of Industrial Engineering, Iran University of Science and Technology (IUST), Iran mrm_aliha@iust.ac.ir F. Berto Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 2b, 7491 Trondheim, Norway A BSTRACT . At intermediate service temperatures hot mix asphalt (HMA) concretely are subjected to different loading rates due to movement of vehicles which can significantly affect their mechanical characteristics and final service load. Hence, in this paper the effect of loading rate on intermediate temperature fracture resistance of HMA materials is investigated experimentally in different modes of cracking. Different hot mix asphalt mixtures made of various compositions were subjected to asymmetric three- point bend loading in the form of edge cracked semi-circular bend (SCB) specimens. The effect of aggregate type and air void were studied on the fracture energy values for three mode mixities (including pure mode I, mixed mode I/II and pure mode II) and at different temperatures of 5°C, 15°C and 25°C. Trends of change in fracture energy values revealed noticeable influence of loading rate on the low and intermediate temperature cracking behavior of tested asphalt mixtures with different air void contents and aggregate types subjected to mixed mode I/II loading. Also, a change observed in fracture resistance of asphalt mixtures at nearly zero (5°C) and intermediate temperatures (25°C) that was due to change in the behavior of bitumen from elastic to viscoelastic. K EYWORDS . Asphalt mixtures; Loading rate effect; Fracture energy; Temperature effect; Air void effect; Mixed mode I/II loading. Citation: Fakhri, M., Haghighat Kharrazi, E., Aliha, M.R.M., Berto, F., The effect of loading rate on asphalt mixture fracture energy at intermediate temperatures under different loading modes, Frattura ed Integrità Strutturale, 43 (2018) 113-132. Received: 17.10.2017 Accepted: 03.11.2017 Published: 01.01.2018 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.