* [41] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]AIL_ADDRESS].ir (M.R.M.A.) * [42] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [EMAIL_ADDRESS] (M.R.M.A.) * [43] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]AIL_ADDRESS] (M.R.M.A.) * [44] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [EMAIL_ADDRESS] (M.R.M.A.) * [45] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [EMAIL_ADDRESS] (M.R.M.A.) * [46] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [EMAIL_ADDRESS] (M.R.M.A.) * [47] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [48] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.M.A.) * [49] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran  
* [72] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [73] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.M.A.) * [74] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [75] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.M.A.A.) * [76] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [77] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [78] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.R.M.A.) * [79] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [80] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.M.A.) * [81] School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran
* [82] Correspondence: [EMAIL_ADDRESS] (D.Y. ); [PERSON]DRESS] (M.R.M.A.) * [9] School of Civil Engineering, Iran University of Science and Technology, N Asphalt overlay containing a top-down crack is often subjected to pure mode I or crack opening failure mode and this is the most common mode of failure due to the cracking of pavement structures. Traffic loads via passing vehicles and daily or seasonal gradient temperatures or freeze-thaw cycles are two major sources of crack propagation inside the pavements (as shown schematically in Figure 1). Indeed, both thermal and mechanical loading mechanisms tend to gradually and repeatedly open the top-down crack faces initiated in the surface of the overlay. In order to assess the crack growth behavior and appropriate pavement repair time, it is necessary to know the mode I fracture toughness value (K\({}_{\text{lc}}\)) for the asphalt mixtures [9; 10; 11]. Fracture toughness (K\({}_{\text{lc}}\)) can be determined experimentally using suitable specimens and relevant test methods. Among the test configurations available for obtaining the K\({}_{\text{lc}}\) value of asphalt mixtures, the following methods have received much attention by the researchers:  
1. Edge cracked rectangular beam loaded with three-point or four-point bending [1; 6; 9; 10; 12];
2. Edge cracked circular compact tension specimen by pin loading (DCT) [1; 2; 13];
3. Edge cracked semi-circular specimen loaded with symmetric three-point bending (SCB) [4; 6; 7; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29];
4. Center cracked Brazilian disc specimen loaded with diametral compression (BD) [30; 31];
5. Edge cracked disc specimen loaded with diametral compression (ENDC) [32; 33];
6. Edge cracked disc specimen subjected to three-point bending (ENDB) [34; 35; 36; 37; 38; 39; 40; 41; 42];
7. Edge cracked circular disc loaded with wedge splitting fixture [43];
8. Indirect diametral disc test [44]. The simplicity of the specimen shape and test geometry is an important issue for conducting the fracture tests on asphalt materials. In addition, the specimen and its loading type should be a good representative for the actual loading conditions that is experienced by the paving materials in the field.