Durability and Mechanical Behavior of Fly Ash-GGBFS Geopolymer Concrete Utilizing Bottom Ash as Fine Aggregate
TL;DR: The mechanical properties and durability parameters such as wet-dry cycles, water sorptivity, efflorescence and acid resistance of geopolymer concrete synthesized from fly ash of three different or...
Abstract: The mechanical properties and durability parameters such as wet-dry cycles, water sorptivity, efflorescence and acid resistance of geopolymer concrete synthesized from fly ash of three different or...
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TL;DR: In this paper, the reported physical and chemical characteristics of coal bottom ash (CBA) are analyzed and the impact of the source (locality) on its characteristics is discussed.
50 citations
TL;DR: In this article, fly ash, ground granulated blast furnace slag (GGBS) and silica fume were used to produce different concrete mixes that were evaluated for mechanical properties, microstructural performance, and environmental impact.
46 citations
01 Apr 2021
TL;DR: In this article, fly and bottom ashes from a thermal-electrical unit were used as sources of aluminosilicate in the synthesis of geopolymers, and the results showed that it is possible to obtain a green cement using coal ashes as raw materials with high solid content.
Abstract: The use of by-products as raw materials in the manufacturing of industrial products has risen in the last years because of environmental considerations. One example is the use of coal ashes from thermal-electrical plants in the production of geopolymer -- a green cement made by mixing aluminosilicate with alkaline activator. In this study, fly and bottom ashes from a thermal-electrical unit were used as sources of aluminosilicate in the synthesis of geopolymers. A mixture of sodium hydroxide (10 mol/L) and sodium silicate (SiO2/Na2O ratio of 2.2) was used as the alkaline activator. The type (fly or bottom ash) and content of the ash were the variables in the synthesis. The ashes were characterized by X-ray fluorescence (XRF), X-ray diffraction (DRX), particle size distribution (PSD), specific surface area (BET), and thermal analysis (DTA/TGA). The ash-based geopolymer samples were measured to obtain their compressive strength after curing. The evolution of the geopolymerization process was also assessed based on final alkali concentration measurements. The results show that it is possible to obtain geopolymers using coal ashes as raw materials with high solid content. The compressive strength for the bottom ash geopolymer after 90 days of curing is 35 MPa. The low concentration of unreacted alkalis after curing (1.5× 10-3 – 3.5 × 10-3 M) corresponds to high efficiency of the geopolymerization reaction.
11 citations
TL;DR: In this article , the effects of high temperatures on the microstructures of AALWACs are examined by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and polarized light microscope (PLM) analyses.
10 citations
TL;DR: In this article , the authors reviewed the requisites of geopolymer concrete to perform like pavement quality concrete while utilizing maximum quantity of wastes in both the binder and aggregate phase.
Abstract: After industrial sector, construction sector utilizes significant quantity of natural raw materials and energy sources. Construction sector waste needs dumping spaces whereas the industrial sector waste like, fly ash and coal bottom ash poses health hazards as they contaminate water, air and soil. Pozzolanic concrete utilizes industrial waste by substituting a portion of cement (<60 %) and offers better durability with similar mechanical properties to normal concrete. Geopolymer concrete, a durable and high-strength concrete, has been devised to fully substitute cement with industrial wastes. This study reviews the requisites of geopolymer concrete to perform like pavement quality concrete while utilizing maximum quantity of wastes in both the binder and aggregate phase. This paper concludes that geopolymer concrete can be used in pavements even with more than 50 % virgin aggregate substitution with recycled aggregates. Further, the mix should be enriched with ground granulated blast furnace slag with sodium hydroxide molarity within 12–16.
8 citations
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TL;DR: A brief history and review of geopolymer technology is presented with the aim of introducing the technology and the vast categories of materials that may be synthesized by alkali activation of aluminosilicates as mentioned in this paper.
Abstract: A brief history and review of geopolymer technology is presented with the aim of introducing the technology and the vast categories of materials that may be synthesized by alkali-activation of aluminosilicates. The fundamental chemical and structural characteristics of geopolymers derived from metakaolin, fly ash and slag are explored in terms of the effects of raw material selection on the properties of geopolymer composites. It is shown that the raw materials and processing conditions are critical in determining the setting behavior, workability and chemical and physical properties of geopolymeric products. The structural and chemical characteristics that are common to all geopolymeric materials are presented, as well as those that are determined by the specific interactions occurring in different systems, providing the ability for tailored design of geopolymers to specific applications in terms of both technical and commercial requirements.
3,302 citations
TL;DR: In the last few years, technological progress has been made in the development of new materials such as "geopolymers" and new techniques, such as ''sol-gel'' as mentioned in this paper, opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry.
Abstract: Spectacular technological progress has been made in the last few years through thedevelopment of new materials such as «geopolymers», and new techniques, such as «sol-gel». New state-of-the-art materials designed with the help of geopolymerization reactions are opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry. High temperature techniques arc no longer necessary to obtain materials which are ceramic-like in their structures and properties
3,178 citations
TL;DR: In this paper, the potential position of and drivers for inorganic polymers (“geopolymers”) as an element of the push for a sustainable concrete industry are discussed.
1,444 citations
TL;DR: In this paper, the effect of mineral properties on the compressive strength of the synthesized geopolymer was investigated, and it was shown that a wide range of natural Al-Si minerals could serve as potential source materials for the synthesis of geopolymers.
1,424 citations
TL;DR: In this paper, a mechanistic model accounting for reduced structural reorganization and densification in the microstructure of geopolymer gels with high concentrations of soluble silicon in the activating solution has been proposed.
1,309 citations