Cotton and Flax Fibre-Reinforced Geopolymer Composites: Synthesis, Properties and Applications (Composites Science and Technology)

This book provides an overview on the latest advances in the synthesis, properties and applications of geopolymers reinforced with natural fibres such as pulp fibre, cotton, sisal, flax and hemp. The influence of adding various natural fibres and nanofillers on the mechanical properties of these composites is discussed. Potential challenges and future directions of these composites are highlighted and addressed. The content of this book caters to students, researchers and academics who are interested in the synthesis and applications of geopolymers composites. Preface 6 Contents 8 About the Authors 11 1 Background 13 1.1 Introduction 13 1.1.1 Overview of Composite Materials 13 1.1.2 Fibre-Reinforced Geopolymer Composites 14 1.2 Literature Review 18 1.2.1 Geopolymers 18 1.2.2 Microstructural Properties of Gopolymers 25 1.2.3 Thermal Properties of Geopolymers 26 1.2.4 Mechanical Properties of Geopolymers 27 1.2.5 Behaviour of Geopolymer Matrices at Elevated Temperatures 35 1.2.6 Fibre Reinforced Geopolymer Composites 37 1.2.7 Applications of Geopolymers 45 References 46 2 Materials and Methodology 53 2.1 Methodology of Synthesis 53 2.1.1 Cotton Fibre Reinforced Geopolymer Composites 53 2.1.2 Cotton Fabric Reinforced Geopolymer Composites 54 2.1.3 Portland Cement Modified Cotton Fabric Reinforced Geopolymer Composites 55 2.1.4 Flax-Fabric Reinforced Geopolymer Composites 56 2.1.5 Flax Fabric Reinforced Geopolymer Nanocomposites 58 2.2 Techniques of Characterisation 59 2.2.1 X-Ray Diffraction and X-Ray Fluorescence 59 2.2.2 Thermogravimetric Analysis (TGA) 60 2.2.3 Scanning Electron Microscopy (SEM) 60 2.2.4 Fourier Transform Infrared (FTIR) Spectra 61 2.3 Physical and Mechanical Properties 61 2.3.1 Density and Porosity 61 2.3.2 Moisture Absorption 61 2.3.3 Flexural Strength and Modulus 62 2.3.4 Impact Strength 62 2.3.5 Rockwell Hardness 63 2.3.6 Fracture Toughness 63 2.3.7 Flexural Toughness and Toughness Indices 63 References 64 3 Physical Properties 65 3.1 Cotton Fibre-Reinforced Geopolymer Composites 65 3.1.1 Synchrotron Radiation Diffraction 65 3.1.2 Density and Porosity 66 3.2 Cotton Fabric-Reinforced Geopolymer Composites 68 3.2.1 Effect of Fibre Content 68 3.2.2 Effect of Nanoclay 68 3.2.3 Effect of Ordinary Portland Cement 72 3.3 Flax Fabric-Reinforced Geopolymer Composites 77 3.3.1 Effect of Flax-Fibre Content 77 3.3.2 Effect of Nanoclay and Flax-Fibre Content 78 3.3.3 Effect of Nanosilica 86 References 95 4 Mechanical Properties 98 4.1 Cotton Fibre-Reinforced Geopolymer Composites 98 4.1.1 Flexural Strength and Modulus 98 4.1.2 Fracture Toughness 100 4.2 Cotton Fabric-Reinforced Geopolymer Composites 102 4.2.1 Effect of Fibre Content and Fabrication Methods 102 4.2.2 Effect of Fabric Orientation 116 4.2.3 Effect of Nanoclay 122 4.2.4 Effect of Ordinary Portland Cement 127 4.2.5 Effect of Elevated Temperature 134 4.3 Flax Fabric-Reinforced Geopolymer Composites 138 4.3.1 Effect of Flax-Fibre Content 138 4.3.2 Effect of Nanoclay 144 4.3.3 Effect of Nanosilica 146 References 155 5 Moisture Absorption and Durability 158 5.1 Cotton Fabric-Reinforced Geopolymer Composites 158 5.1.1 Water Absorption Behaviour 158 5.1.2 Flexural Strength 159 5.1.3 Flexural Modulus 161 5.1.4 Impact Strength 163 5.1.5 Hardness 164 5.1.6 Fracture Toughness 165 5.2 Flax Fabric-Reinforced Geopolymer Composites 167 5.2.1 Effect of Nanoclay 167 5.2.2 Effect of Nanosilica 176 References 184 6 Thermal Stability and Flammability 188 6.1 Cotton Fabric Reinforced Geopolymer Composites 188 6.1.1 Effect of Elevated Temperature 188 6.1.2 Effect of Nanoclay 193 6.1.3 Effect of Ordinary Portland Cement 195 6.2 Flax Fabric Reinforced Geopolymer Composites 197 6.2.1 Effect of Composition 197 6.2.2 Effect of Nanoclay 198 References 199 7 Summary and Concluding Remarks 201 7.1 Summary on Cotton Fibre Reinforced Geopolymer Composites 201 7.1.1 Short Cotton Fibre Reinforced Geopolymer Composites 201 7.1.2 Cotton Fabric-Reinforced Geopolymer Composites 202 7.2 Summary on Flax Fibre Reinforced Geopolymer Composites and Nanocomposites 206 7.2.1 Flax Fabric-Reinforced Geopolymer Composites 206 7.2.2 Nanoclay-Filled Geopolymer Composites 206 7.2.3 Nanoclay-Filled Flax Fabric-Reinforced Geopolymer Composites 207 7.2.4 Nanosilica-Filled Geopolymer Composites 208 7.2.5 Nanosilica-Filled Flax Fabric-Reinforced Geopolymer Composites 209 7.2.6 Durability of Flax Fabric Reinforced Geopolymer Nanocomposites 210 7.3 Concluding Remarks and Future Directions 211