An Investigation into the Role of Nano-Silica in Improving Strength of Lightweight Concrete

Abstract

Development of technology and human’s access to nanotechnology brings about the necessity to use nanotechnology in the concrete industry. Since the decrease of particles size leads to new properties, and unusual mechanical, electrical, and magnetic properties which are inaccessible in usual state, nanotechnology is highly considered. The emergence of nanotechnology in concrete industry has made great changes in many of the concrete properties. Dead load resulted from weight of ceilings and separation walls is one of the fundamental problems in seismic design and structures implementation especially in tall buildings. Obviously, using the lightweight materials could decrease the dead load, weight of beams, columns, and foundation. However, low compressive resistance of lightweight concrete mostly has a direct ratio with the specific gravity of it. Lightweight concrete has a low resistance as a result of its low specific weight. Silica nanoparticles (SNs) have a high surface energy as a result of their high specific surface.  Therefore, they are supposed to have a high pozzolanic reaction and they accelerate hydration reactions. Since the increase of concrete compressive strength is highly noticeable in the new technology, the increase of effective materials with the purpose of increasing compressive strength of concrete could increase the life circle of concrete structures. The present paper intends to investigate the effect of silica nanoparticles on compressive strength, tensile strength, bending strength, contraction of lightweight concrete, and concrete microstructure.