Issue 42

A. Jadidi et alii, Frattura ed Integrità Strutturale, 42 (2017) 249-262; DOI: 10.3221/IGF-ESIS.42.27 257 28-day bending strength of all samples has increased. Based on these results, the highest 28-day bending strength exists in samples reinforced with 2.5% hybrid steel fibers (hooked steel fibers L/D=30 and crimped steel fibers L/D=50) with 12.96 MPa and 329% bending strength increase. Figure 11 : Impact of steel fiber content on 28-day bending strength of steel fiber-reinforced concrete. Based on Fig. 12 the lowest bending strength increase exists in samples reinforced with 1.5% steel fibers L/D=50 with 5.16 MPa and 70.86 bending strength increase. Figure 12 : Impact of steel fiber content on 28-day bending strength of steel fiber-reinforced concrete. Addition of steel fibers in bending test contributes to increased toughness and energy absorption which play an important role in the type of concrete fracture. The use of fibers causes an increase in concrete tensile toughness and softer behavior. Figure 13 : Load-displacement graph for fibreless sample on 28-day.