Issue 78

M. S ł owik et alii, Fracture and Structural Integrity, 78 (2026) 393-408; DOI: 10.3221/IGF-ESIS.78.23

In summary, these observations confirm that aggregate type plays a crucial role in the tensile splitting behaviour of concrete. Surface roughness and angularity of granite aggregate enhanced mechanical interlocking and bonding with the cement matrix, leading to a more resistant fracture path. Although cement matrix strength can affect cracking, the visual evidence suggests its impact is secondary to that of aggregate type in the tested concretes. The experimental findings and visual documentation provided a deeper insight into how aggregate type influences the splitting tensile strength of concrete.

C ONCLUSIONS

T

he presented experimental study aimed to provide a more detailed evaluation of how selected parameters: the strength of the cement matrix and the type of coarse aggregate, affect concrete’s splitting tensile strength. The analysis of the gathered laboratory data led to the following conclusions:  Concrete with a stronger cement matrix exhibited higher splitting tensile strength. However, for an equivalent increase in cement mortar strength, the corresponding increase in splitting tensile strength was more than twice as large in concrete with natural gravel aggregate compared to the one containing crushed granite aggregate.  For concretes produced with the same maximum aggregate size, higher splitting tensile strength was observed in mixes incorporating crushed granite aggregate than in those with gravel aggregate. The analysis of the contribution of individual components to tensile performance indicated that the cement matrix strength is the governing factor in concretes with gravel aggregate, whereas in concretes with granite aggregate, the aggregate strength itself plays a more decisive role.  A different influence of concrete components, such as cement matrix and coarse aggregate, on splitting tensile strength was explained on the basis of the character of crack propagation at failure. For concretes with gravel aggregate, the influence of the cement mortar was more apparent, as the failure crack surrounded aggregate grains and ran through the cement matrix. For concretes with crushed granite aggregate, the crack ran not only through the cement matrix but in several cases also through aggregate grains, causing their crushing. The different crack propagation is probably due to the stronger bond between the cement mortar and the granite aggregate grains. [1] EN 12390-3 (2019). Testing Hardened Concrete—Part 3: Compressive Strength of Test Specimen. European Committee for Standardization, Brussels, Belgium. [2] EN 12390-6 (2011). Testing Hardened Concrete—Part 6: Tensile Splitting Strength of Test Specimen. European Committee for Standardization, Brussels, Belgium. [3] RILEM TC-50 FMC (1985). Determination of the fracture energy of mortar and concrete by means of three-point bend tests on notched beams. Mater. Struct., 18(106), pp. 285–290. [4] RILEM TC-89 FMC (1991). Determination of fracture parameters (KIc and CTODc) of plain concrete using three point bend tests. Mater. Struct., 23, pp. 457–460. [5] Zhong, W., Pan, J., Wang, J. and Zhang, C. (2020). Size effect in dynamic splitting tensile strength of concrete: Experimental investigation. Constr. Build. Mater., 270. DOI: https://doi.org/10.1016/j.conbuildmat.2020.121449. [6] Liu, J., Yu, W., Du, X. and Yang, W. (2019). Mesoscopic numerical simulation of dynamic size effect on the splitting tensile strength of concrete. Eng. Fract. Mech., 209, pp. 317–332. [7] Suchorzewski, J., Tejchman, J. and Nitka, M. (2018). Experimental and numerical investigations of concrete behaviour at meso-level during quasi-static splitting tension. Theor. Appl. Fract. Mech., 96, pp. 720–739. [8] Pan, J., Zhong, W., Wang, J. and Zhang, C. (2022). Size effect on dynamic splitting tensile strength of concrete: Mesoscale modeling. Cem. Concr. Compos., 128. DOI: https://doi.org/10.1016/j.cemconcomp.2022.104435. [9] Zhang, L., Zheng, Y., Hu, S. and Du, C. (2025). Size effect difference between uniaxial and splitting tensile strength of recycled aggregate concrete considering the maximum aggregate size: Meso-simulation. Constr. Build. Mater., 462. DOI: https://doi.org/10.1016/j.conbuildmat.2025.139961. [10] Yu, W., Jin, L., Du, X. and Chen, F. (2022). Coupling influence of low strain rate and structural size on splitting-failure of concrete: Tests and mechanism analysis. Constr. Build. Mater., 323. DOI: https://doi.org/10.1016/j.conbuildmat.2022.126641. [11] S ł owik, M. and Akram, A. (2022). Length Effect at Testing Splitting Tensile Strength of Concrete. Materials, 15. R EFERENCES

406