Investigating the Effect of Using Macro and Micro Steel Fibers with Nano Silica on the Mechanical Properties of Concrete

Using fibers with different sizes and types part plays more important roles in energy absorption capability of reinforced concrete structures. The effects of different sizes and proportions of fibers on energy absorption capability, bending strength, tensile and compressive strength of concrete have been investigated in this work. Steel fibers have been used to improve the post fracture behavior of concrete and pozzolanic materials have been added to concrete to increase the strength of transition zone. In this regard, the combination of fibers in different sizes for bridging the cracks at different stages of the crack growth and also using nano silica with high surface energy and reactivity can be considered. Simultaneous use of mentioned additives can improve the properties of concrete in the case of using appropriate mix design. Different mix designs containing combinations of different types of steel fibers and micro silica and nano silica have been tested and an optimized mix design of concrete with improved mechanical properties has been reached. Energy absorption capability, bending strength, tensile and compressive strengths can be mentioned as those mechanical properties.