Determination of fracture toughness (K_Ic) for the asphalt mixture concrete requires employment of suitable testing methods and specimens. Disc-shape specimens are among the favorite test geometries for conducting the fracture toughness experiments on asphalt concrete materials since they can be manufactured easily from those samples obtained by the gyratory compactor machine. Semi-circular bend (SCB) and edge notch disc bend (ENDB) specimens are two suitable and well-known specimens in this regard, and both of them are tested using three-point bend setup. In order to compare the consistency of fracture toughness results obtained from these two specimens, an experimental study is performed herein on a typical asphalt concrete mixture. In the experiments, the thickness of SCB and ENDB specimens and also the loading rate and test temperature are considered as variable. It is found that the K_Ic values obtained from both SCB and ENDB testing methods are in good agreement. The corresponding value of K_Ic obtained from the SCB specimen being slightly smaller than the data obtained from the ENDB specimen. Using a two term K_I + T strain-based fracture model, that the critical normal strain value for both specimens is shown to be nearly the same and constant for both SCB and ENDB specimens. In addition, it is found that the fracture toughness value and load carrying capacity of asphalt mixture increases by increasing the specimen thickness (from 30 to 70 mm) and the loading rate (from 1 to 6 mm/min), and by decreasing the test temperature (from −15 °C to −25 °C).

断裂韧性的测定（K _Ic）对于沥青混合料混凝土需要使用合适的测试方法和样本。圆盘形试样是在沥青混凝土材料上进行断裂韧性试验的最喜欢的测试几何形状，因为它们可以很容易地从旋压夯实机获得的试样中制造。在这方面，半圆弯曲（SCB）和圆口缺口圆盘弯曲（ENDB）样品是两个合适的且众所周知的样品，并且它们都使用三点弯曲设置进行了测试。为了比较从这两个样品获得的断裂韧性结果的一致性，本文对典型的沥青混凝土混合物进行了实验研究。在实验中，SCB和ENDB样品的厚度以及加载速率和测试温度都被认为是可变的。发现，从SCB和ENDB测试方法获得的K _Ic值非常吻合。从SCB样品获得的K _Ic的相应值略小于从ENDB样品获得的数据。使用基于K _I  +  T应变的两个术语的断裂模型，两个标本的临界法向应变值显示为几乎相同，并且对于SCB和ENDB标本都是恒定的。此外，发现通过增加试样厚度（从30到70 mm）和加载速率（从1到6 mm / min）并通过降低试验，沥青混合料的断裂韧性值和承载能力增加。温度（从-15°C到-25°C）。