Portland cement based concrete is the most versatile, durable and reliable building material. Unfortunately, the production of Portland cement is environmentally unfriendly. An interesting alternative is provided by alkali-activated geopolymer materials (AAGM). This book focuses on fly ash-based alkali-activated geopolymer concrete, its production and characteristic properties. The re-use of waste materials and industrial by-products, such as fly ash, is not only economically of interest but also helps to reduce carbon dioxide emissions. The carbon footprint of these materials is much lower than that of concrete using ordinary Portland cement. They thus offer new sustainable solutions to the construction industry.
Keywords: Geopolymers, Geopolymer Concrete, Alkali-activated Geopolymer Materials (AAGM), Portland Cement, Fly Ash-based Geopolymer Concrete, Reduction of Carbon Dioxide Emissions, Concrete Applications, Self-Compacting Concrete, High-strength Concrete, High-performance Concrete.
Author(s): Adrian Lăzărescu, Henriette Szilágyi, Cornelia Baeră
Series: Materials Research Foundations
Publisher: Materials Research Forum LLC
Year: 2021
Language: English
Pages: 138
City: Millersville
Alternative Concrete – Geopolymer Concrete
Table of Contents
Introduction
Acknowledgement
Global Perspectives on the Production of Industrial By-Products in the Context of "Circular Economy”
Retrospective Regarding Research in the Field of Alkali-Activated Geopolymer Materials
2.1. Geopolymers and geopolymerisation – chemical characteristics
2.2. Geopolymers and geopolymerization – mechanical characteristics
2.3. Types of alkaline activators used in the synthesis of geopolymers
2.4. Alkali-activated geopolymer materials mix-design
2.4.1. Properties of the alkaline activator
2.4.2. Heat curing procedures
2.5. Properties of alkali-activated geopolymer materials
2.5.1. Mechanical properties of alkali-activated geopolymer materials
2.5.2. Durability of alkali-activated geopolymer materials
2.5.3. Remarks
2.6. Factors influencing alkali-activated geopolymer materials
2.6.1. Physical and chemical properties of fly ash
2.6.2. Alkaline activator and heat treatment properties
2.6.3. Mixing procedure
2.7. Alkali-activated geopolymer materials applications
Raw Materials Used in the Production of Alkali-Activated Geopolymer Materials
3.1. Why alkali-activation?
3.2. Portland cement and fly ash
3.2.1. Fly ash for cement
3.2.2. Fly ash for construction industry
3.2.3. Fly ash as type II addition for concrete
3.2.4. General conditions for producing fly ash
Development of Alkali-Activated Geopolymer Binder
4.1. General principles for the production of alkali-activated geopolymer materials
4.2. Alkali-activated fly ash-based geopolymer paste – raw materials characteristics
4.2.1. Fly ash (FA)
4.2.2. Alkaline activator (AA)
4.3. Alkali-activated fly ash-based geopolymer paste technology
4.4. Alkali-activated fly ash-based geopolymer paste characteristics
4.4.1. Alkali-activated geopolymer paste mixtures (AAGP)
4.4.2. Physical-mechanical properties of the alkali-activated geopolymer paste mixtures
4.4.3. Technological and mix-design influences on the performance of alkali-activated geopolymer binder
4.4.3.1. Influence of age on the compressive strength
4.4.3.2. Influence of the alkaline activator to fly ash ratio (AA/FA) on the compressive strength
4.4.3.3. Influence of the alkaline activators ratio (Na2SiO3/NaOH) on the compressive strength
4.4.3.4. Influence of the molar concentration of the NaOH solution on the compressive strength
4.4.3.5. Interdependence between molar concentration of NaOH solution and water in the mixture
4.4.3.6. Fly ash type influence on the compressive strength
4.4.3.7. Influence of fly ash physical properties on the compressive strength
4.4.4. Microscopic evaluation of alkali-activated geopolymer paste mixtures
Development of Alkali-Activated Fly Ash-Based Geopolymer Concrete
5.1. Raw materials characteristics
5.2. Alkali-activated fly ash-based geopolymer technology
5.3. Alkali-activated fly ash-based geopolymer concrete mixtures
5.4. Alkali-activated fly ash-based geopolymer physical-mechanical properties
5.4.1. Fresh-state properties
5.4.2. Apparent density
5.4.3. Flash setting
5.4.4. Physical-mechanical properties of the alkali-activated geopolymer concrete mixtures
5.4.5. Microscopic evaluation
5.5. Technological and mix-design influences on the performance of alkali-activated geopolymer concrete
5.5.1. Influence of the molar concentration of the NaOH solution on the compressive strength
5.5.2. Influence of NaOH type on the compressive strength of AAGC mixtures
5.5.3. Influence of Na2SiO3/NaOH ratio on the compressive strength of AAGC mixtures
Research Regarding Alkali-Activated Fly Ash-Based Geopolymer Concrete Applications
6.1. Alkali-activated fly ash-based geopolymer panels
6.2. Alkali-activated fly ash-based geopolymer paving blocks
6.3. Legislative framework on the possibility of using alkali-activated geopolymer paving blocks
Conclusions and Final Remarks
References
List of Symbols
About the Authors
