Modeling of the fracture propagation in heterogeneous material based on reconstructed microstructure

Recently, X-ray tomography is used to explore the microstructure of different materials non-destructively.Here, we utilized it for the reconstruction of the microstructure of cement-mortar.Cement-mortar was prepared by mixing the cement and sand in a ratio of 1:1.The phase distribution in the cement mortar is quite complex due to the random size and distribution of the sand particles.Also, the contrast between sand and cement is low due to their neighboring densities.Thus, a combined distribution of greyscale values exists in the reconstructed images in these phases of the mortar, which makes the segmentation process difficult.However, the segmentation of the voids at this length scale resolution is possible by defining a suitable greyscale cut-off value.Here, we have used an optimum window and median-based greyscale markers to differentiate these phases for segmentation.Later, the segmented image was meshed into the finite elements, and the fracture process of the mortar is predicted using concrete damage plasticity.The predicted effective stress/strain response of the specimen was similar to one reported in the literature for concrete.It is found that the response is consistent with the previously reported observations.The elastic and softening behavior of the cement mortar is captured.