Size effect in normal- and high-strength amorphous metallic and steel fiber reinforced concrete beams

In this study, the size effect on the flexural behavior of amorphous metallic fiber reinforced concrete (AM-FRC) was investigated. For this, several AM-FRC beams having three different sizes were fabricated with different values of water-to-cementitious material (w/cm) ratio and fiber volume fraction. In order to estimate the implication of fiber type on the size effect, steel fiber reinforced concrete (SFRC) having the same mixture proportion as that of the AM-FRC and 0.75% by volume of hooked-end steel fibers were also fabricated and tested. The experimental results showed that lower flexural performance including flexural strength, normalized deflection capacity, and normalized toughness was obtained with an increase in the specimen size, regardless of w/cm ratio and volume content and type of fibers. High-strength concrete was more sensitive to the size effect on flexural strength than normal-strength concrete, whereas less sensitivity to the size effect was observed with an increase in the fiber volume content. The effectiveness of using hooked-end steel fibers in reducing the size effect was greater for high-strength concrete compared to normal-strength concrete, due to the better fiber bond performance.