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2023 | Buch

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Silica Fume in Geopolymers

A Comprehensive Review of Its Effects on Properties

verfasst von: Alaa M. Rashad

Verlag: Springer Nature Switzerland

Buchreihe : SpringerBriefs in Applied Sciences and Technology

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

This book provides a comprehensive review of past studies that have investigated the effects of Silica Fume (SF) on the properties of geopolymers in its three different forms: as an additive to the precursor, as part of an activator, or as a foaming agent. By analyzing previous studies, this book aims to provide a clear understanding of the positive and negative effects of recycling SF into various geopolymer types. It is a valuable resource for researchers, academics, and professionals working in the field of geopolymer technology and cementitious materials.

Inhaltsverzeichnis

Frontmatter

1. Introduction

Abstract

Silica fume (SF) is a by-product of ferrosilicon alloys or the silicon metal industry. Due to its high fineness and amorphous silica, it is widely used in Portland cement (PC) systems as a cementitious material to enhance the durability and mechanical properties. In recent developments, numerous studies have been implemented to obtain superior properties of various types of geopolymer by incorporating SF. On the whole, SF can be recycled into geopolymers in three various forms: as an additive to the precursor or as a part of a precursor, as a part of an activator or as a foaming agent. Recycling SF into various geopolymer types may have a positive effect or an adverse effect. This mainly depends on precursor/SF fineness, activator concentration and type, activator/binder ratio, testing age, curing condition, SF amount and Si/Al ratio. The target of this document is to review, summarize and analyse the past studies focused on the effect of SF, in its three various forms, on the properties of geopolymers.

Alaa M. Rashad

2. Silica Fume as a Part of Precursor/An Additive

Abstract

Due to the prospective properties of silica fume (SF), it is frequently used in Portland cement (PC) systems as a supplementary cementitious ingredient to improve the mechanical and durability properties. In recent developments, numerous studies have been implemented to obtain superior properties of various types of geopolymer by incorporating SF. In spite of SF can be incorporated into geopolymers in various forms, most of the past studies employed it as a part of precursor/an additive. However, recycling SF as a cementitious material (as a part of precursor) into various geopolymer types may have a positive effect or an adverse effect. This mainly depends on precursor/SF fineness, activator concentration and type, activator/binder ratio, testing age, curing condition, SF amount and Si/Al ratio. The target of this part is to review, summarize and analyse the past studies focused on the effect of SF, as an additive or a part of precursor, on workability, setting time, density, mechanical strength and different durability aspects of various types of geopolymer.

Alaa M. Rashad

3. Silica Fume as an Activator Component

Abstract

As known, NaOH and sodium silicate are widely used as alkaline activators for preparing geopolymers due to better obtained strength. Unfortunately, the manufacture of these activators is somewhat costly and requires a lot of energy. This is particularly true for sodium silicate, which is made by melting sodium carbonate and sand at 1350–1450 °C, then dissolving the glass that is created in an autoclave at 140–160 °C under the prober steam pressure. This procedure generates a lot of CO₂ emissions. Employing by-product material such as silica fume (SF) as a part of activator may mitigate these problems. In this part, the earlier studies that used SF as a part of activator were collected. The effect of this activator on the properties of different geopolymer types was reviewed, summarized and analysed.

Alaa M. Rashad

4. Silica Fume as a Foaming Agent

Abstract

The incorporation of foaming or blowing agent in the geopolymer can produce porous microstructure, which improves the effectiveness of its thermal insulation. Improving the thermal insulation effectiveness can save energy and absorb acoustic. The target of this part is to review, summarize and analyse the past studies focused on the effect of SF, as a foaming agent, on density, porosity, thermal conductivity, sound absorption and compressive strength of various types of geopolymer.

Alaa M. Rashad

5. General Perspective and Suggestions for Upcoming Work

Abstract

In spite of silica fume (SF) can be incorporated into different geopolymer types as a part of precursor, as a part of activator or as a foaming agent, most of the earlier studies employed SF as a part of cementitious material (as a part of precursor or an additive) (~ 74.1%), whilst employing it as a part of activator came in the second place (14.81%). Finally, employing SF as a foaming agent came in the last place (11.11%). In this part, the percentage of studies about the effect of SF as a part of precursor on each property of geopolymers was established and compared. The effect of SF in its three forms (part of precursor, part of activator and foaming agent) on the various geopolymer types was summarized.

Alaa M. Rashad

6. General Remarks

Abstract

Herein, the incorporation of SF as a part of a precursor, as a part of activator and as a foaming agent for geopolymers has been comprehensively reviewed, summarized and analysed. The main outcomes can be briefed as follows.

Alaa M. Rashad

Titel: Silica Fume in Geopolymers
verfasst von: Alaa M. Rashad
Verlag: Springer Nature Switzerland
Electronic ISBN: 978-3-031-33219-7
Print ISBN: 978-3-031-33218-0
DOI: https://doi.org/10.1007/978-3-031-33219-7

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