Document Type : Research Paper
Phd student of structural engineering, Department of Civil Engineering, Faculty Engineering, Razi University, Kermanshah, Iran
Associate Professor, Department of Civil Engineering, Faculty of Engineering, Razi University,Kermanshah, Iran
The problem of failure brings about considerable financial and living costs to various societies every year. The issue came under a scientific scrutiny since the beginning of the twentieth century. For the macro scale analysis of concrete structures, concrete is assumed as a homogeneous material, whereas in reality concrete contains various components such as cement paste, sand and air, which are important for concrete behavior determination. Therefore, in the current research, to calculate concrete failure parameters, cement paste and 4 different aggregate sizes were modelled to examine the effect of aggregates in the cement paste. According to the random distribution of the aggregates in the cement paste, 100 different types of the aggregate distribution in the cement paste were modeled to evaluate a wide range of responses. By examining the results obtained from 100 numerical samples of the bending beam under the three-point test, an unexpected result was obtained. It is normally expected that only the failure coefficient of the first mode should be created under this experiment. However, the failure coefficients of the second and third modes were also created due to the distribution of aggregates. The amount of these modes are probably dependent on aggregates and their location. The existence of all three failure modes contributes to the inconsistency of energy release rate distribution in the thickness, and the final result is the early failure of the sample.