Using Colloidal Nano Silica to Enhance the Performance of Cementitious Mortars

Achraf Ayad,Aly Said

doi:10.4236/ojce.2018.81007

Abstract

Nanomaterials have been widely used in the past few decades due to their proven capacity to enhance the mechanical properties of materials. While many studies have sought to improve the understanding of how nanomaterials affect the behavior of concrete, additional research is needed in order to achieve the full potential of the material, especially in the presence of supplementary cementitious materials. This study aims to investigate the mechanical properties of cement mortars incorporating both nano-silica (NS) and class F fly ash (FA). Furthermore, mercury intrusion porosimetry (MIP) was performed to study its effect on pore characteristics, and thermogravimetric analysis (TGA) was performed to measure the calcium hydroxide Ca(OH)2 content in the mixtures. It was found that using nano-silica enhances the compressive strength, reduces the total porosity and accelerates the pozzolanic reaction.

Highlights

The use of supplementary cementitious materials (SCM) reduces the embodied energy in concrete considerably
This study aims to investigate the mechanical properties of cement mortars incorporating both nano-silica (NS) and class F fly ash (FA)
This paper aims to investigate the combined effect of using NS and fly ash on cement mortars’ compressive strength, porosity and pozzolanic activity

Summary

Introduction

The use of supplementary cementitious materials (SCM) reduces the embodied energy in concrete considerably. It significantly improves the durability of concrete and increases its lifecycle leading to a more sustainable design. Despite the available literature on nanotechnology and its applications in the construction industry, further research is needed on the effect of using nano silica (NS) in concrete, especially when combined with SCMs. Fly ash is the most commonly used supplementary cementitious material in the cement industry because of its various advantages like increased flowability [1], and strength gain at later ages. Said strength gain at early ages [2] [3]. Researchers have examined the effects of using NS in pastes [4], mortars [5]

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Conclusion