Compressive strength of concrete specimens with inclusions

Large diameters and grain aggregates and/or reinforcing bars can have a negative impact on the strength of concrete elements. Tests of concrete specimens with inclusions under uniaxial compression should contribute to a better understanding of the process of failure of concrete elements. The identification of the unstable phase of the cracking and quantification of the effect of diameters, positions, distances, number and material of inclusions, as well as the relative size of inclusions and matrix on compression strength could provide information for an explanation of the causes of the size effect in compressed structural elements. The introduction of the article provides a brief overview of the problem of concrete structures subjected to uniaxial compression. Attention is paid to the failure mechanisms in the process of loading the test specimens from initial crack formation to specimen collapse. The second part is devoted to the investigation of the size effect of varying dimensions of the test specimens with one or three inclusions.