Issue 35

S. Tarasovs et alii, Frattura ed Integrità Strutturale, 35 (2016) 271-277; DOI: 10.3221/IGF-ESIS.35.31 273 Figure 2 : Steel fiber modeling by non-linear springs. Figure 3 : Determination of the fiber orientation angle. E XPERIMENTAL PART ver decades many works have shown the advantages of fiber reinforced concrete (FRC)[8]. In FRC the amount and shape of the steel fibers plays an important role on composites mechanical properties. In this study 2% volume fraction of “hook-end” steel fibers is chosen. Commercially available steel fibers HE 75/50 were used with geometrical parameters shown in Tab. 1 and Fig. 4. Fiber diameter, d 0.75 ± 0.04 mm Fiber length, L 50.0 ± 3 mm Hook length, l and l’ 1 – 4 mm Table 1 : Parameters of hooked steel fiber used in experiments. Figure 4 : Geometry of steel fiber HE 75/50 used in experiments. It is well known that fibers orientation has large effect on the structural strength of fiber-reinforced concrete [9], [10]. In order to evaluate single fiber and matrix interfacial properties, single fiber pull-out tests (SFPT) were performed. The fibers embedded in half of total fiber length (L) were located at different angles (0, 20, 40 and 60 degrees) according to the O