Samet ÖZTÜRK, Varol KOÇ
Many linear and non-linear approaches are used in calculations and models for failure analysis in concrete and reinforced concrete structures. When these approaches are made in accordance with the principles of fracture mechanics, more realistic results are obtained. However, the increase in the accuracy of these approaches depends on the increase in experimental studies in the literature based on element-system geometries and concrete type. Beam specimens have been widely used in the fracture mechanics tests of concrete since ancient times. However, cube and cylindrical samples are preferred recently due to their light weight and ease of transport. Additionally, since the dimensions are proportionally enlarged, it is advantageous to ensure that the largest sized sample batches will fit in the test frames. In addition, these sample geometries are preferred for studying compressive failures apart from bending-tensile failures. In the experimental studies conducted on concrete samples with different geometric shapes in the literature, it has been observed that there is an inverse proportionality between the sample sizes and the nominal compressive strength. This is called the size effect in fracture mechanics. Based on the results obtained according to the fracture loads obtained in the concrete samples as a result of the studies carried out under laboratory conditions, size effect curves can be drawn and size effect parameters can be obtained. In this study, notched concrete cube samples were tested under pressure failure. A total of 48 notched concrete cube samples were tested from C20 concrete in 1:2:4 size and notch ratios. The relationships between the specimen dimensions and the fracture loads obtained from the experiments showed that there were changes in the stresses compatible with the size effect. The relationship between the concrete strengths and the size effect was established and it was clearly seen that there were differences according to the results obtained from the experiment according to the sample sizes. ORCID NO: 0009-0003-3765-6353

Anahtar Kelimeler: Fracture Mechanics, Concrete Size Effect, Compressive Strength,