Mechanical Performance and Microstructure of High Strength Concrete Using Nano-Silica

Abstract

Nowadays, high strength and high-performance concrete are being widely used all over the world. Most applications of high strength concrete have been in tall rise buildings, long-span bridges, and some unique applications in structures. In the present experimental investigation, an attempt has been made to examine the effect of nano-silica by partially replacing it with cement (0.5–4%) for M45 grade of concrete. For evaluating concrete performance, different mechanical tests were performed like compressive and flexural strength. Load–deflection and microstructural characteristics of nanomodified concrete were also studied to examine the influence of nano-silica on concrete properties. It was concluded that concrete made with upto 3% nano-silica replacement by cement showed an increase in strengths after 28 days of curing. The optimum content of nano-silica for various mechanical properties was found at 3%. The pores and voids in concrete can be minimized by incorporating nano-silica, which was observed through microstructural characterization by SEM images.