Flexural properties of fiber reinforced concrete containing silica fume and nano-silica

In this study, the effects of silica fume, nano-silica and polypropylene fibers on the flexural properties of concrete are investigated. The main focuses of this research are on the flexural strength and fracture energy of fiber reinforced concrete. To study the fracture energy of the concrete, flexural test is used. Polypropylene fibers increased the fracture energy and flexural strength of the specimens. Response surface method is used to find the relationships between the mentioned parameters and the amounts of silica fume, nano-silica and fibers. The best mixture with the maximum flexural strength and fracture energy contained 5% silica fume, 0.75% nano-silica and 0.15% fibers. According to scanning electron microscope (SEM) images, silica fume and nano-silica increased the homogeneity and density of the samples.