In this study, as the first step towards understanding the behavior of the mortar around an aggregate, comparisons have been made between the strain distributions, just prior to sample fracture, around different aggregates in mortar specimens containing just a single aggregate particle. We calculated the displacement field inside each specimen by Digital Volume Correlation (DVC) analysis of tomography images acquired first before loading and the second under maximum loading. The DVC was performed with the program “TomoWarp2”. The study showed that if a particle is inserted into the mortar, the shrinkage strains are inhibited and the shear strains occur around the surface of particles. The regions of elevated shear strain become cracks at sample fracture. The region of elevated shear strain is larger for softer particles.