Comparative mechanical and microstructural properties of high calcium fly ash one-part geopolymers activated with Na2SiO3-anhydrous and NaAlO2

Wan-En, Ooi; Yun-Ming, Liew; Cheng-Yong, Heah; Abdullah, Mohd Mustafa Al Bakri; Li, Long-yuan; Ho, Li-Ngee; Loong, Foo Kai; Shee-Ween, Ong; Hui-Teng, Ng; Yong-Sing, Ng; Jaya, Nur Ain

doi:10.1016/j.jmrt.2021.10.018

Cited by 30 publications

(8 citation statements)

References 45 publications

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“…The most comprehensive 28-day compressive strength data for various one-part geopolymer pastes was collected from accessible, pertinent data in the open literature [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. The database comprises 80 FA/GGBS binder-based one-part geopolymers made with an anhydrous sodium silicate alkaline source, see Table 1 .…”

Section: Methodsmentioning

confidence: 99%

Optimization of Fly Ash—Slag One-Part Geopolymers with Improved Properties

et al. 2023

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One-part geopolymer concrete/mortar is a pre-mixed material made from industrial by-products and solid alkaline activators that only requires the addition of water for activation. Apart from being environmentally friendly, it also reduces complexity and improves consistency in the mixing process, leading to more efficient production and consistent material properties. However, developing one-part geopolymer concrete with desirable compressive strength is challenging because of the complexity of the chemical reaction involved, the variability of the raw materials used, and the need for precise control of curing conditions. Therefore, 80 different one-part geopolymer mixtures were compiled from the open literature in this study, and the effects of the constituent materials, the dosage of alkaline activators, curing condition, and water/binder ratio on the 28-day compressive strength of one-part geopolymer paste were examined in detail. An ANN model with the Levenberg–Marquardt algorithm was developed to estimate one-part geopolymer’s compressive strength and its sensitivity to binder constituents and alkaline dosage. The ANN model’s weights and biases were also used to develop a CPLEX-based optimization method for achieving maximum compressive strength. The results confirm that the compressive strength of one-part geopolymer pastes increased by increasing the Na2O content of the alkaline source and the slag dosage; however, increasing the Na2O content in alkaline sources beyond 6% by fly ash weight led to decreasing the compressive strength; therefore, the optimum alkaline activator dosage by weight of fly ash was to be 12% (i.e., 6% Na2O). The proposed ANN model developed in this study can aid in the production and performance tuning of sustainable one-part geopolymer concrete and mortar for broader full-scale applications.

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Section: Methodsmentioning

confidence: 99%

Optimization of Fly Ash—Slag One-Part Geopolymers with Improved Properties

et al. 2023

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“…82,84 However, beyond the optimal value, an increase in Na 2 SiO 3 viscosity can impede the contact between the raw material and the alkaline solution, obstruct the discharge of air bubbles, and lead to the failure of geopolymer formation. 85,86 Moreover, a high modulus of Na 2 SiO 3 causes the silica-aluminate and geopolymerization structures to depolymerize, thereby breaking down the formed network structure and reducing the compressive strength of the geopolymer. 10,87 Na 2 SiO 3 can also function as a reactant by supplying a large amount of amorphous silicate monomers that directly react with the dissolved silica-aluminate monomers to form geopolymers, which improves the Si/Al ratio in the system and creates a more stable geopolymer structure.…”

Section: Alkali Activatormentioning

confidence: 99%

“…The observed behavior can be attributed to the dissolution of more Si and Al ions, resulting in increased geopolymerization, which occurs due to the increased OH − and Na 2 O in the solution with an increase in the modulus of Na 2 SiO 3 82,84 . However, beyond the optimal value, an increase in Na 2 SiO 3 viscosity can impede the contact between the raw material and the alkaline solution, obstruct the discharge of air bubbles, and lead to the failure of geopolymer formation 85,86 . Moreover, a high modulus of Na 2 SiO 3 causes the silica‐aluminate and geopolymerization structures to depolymerize, thereby breaking down the formed network structure and reducing the compressive strength of the geopolymer 10,87 .…”

Section: Properties Of Sludge Geopolymermentioning

confidence: 99%

Sludge‐based geopolymer materials: A review

Kong,

Shi,

Shen

et al. 2024

Int J Applied Ceramic Tech

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Sludge refers to the solid waste produced after sewage treatment. Unreasonable disposal of sludge can cause environmental pollution. Nonetheless, the sludge contains large amounts of silica‐aluminate, which has pozzolanic activity by treatment, and the sludge can be used as a sustainable building material. The previous studies have recommended that it is reasonable to produce geopolymers, that is, a green low‐carbon cementitious material with excellent mechanical and durability properties, from sludge. This article provides an overview of recent advancements in the study of sludge‐based geopolymer. It delves into the mechanisms behind alkali‐activated geopolymer, examines the feasibility of preparing geopolymer from sludge, and discusses various preparation methods. Additionally, it elaborates on the impact of incorporating different auxiliary materials on sludge‐based geopolymer. The comprehensive performance of sludge‐based geopolymer, encompassing mechanical properties, durability, and setting time, is thoroughly summarized. An environmental assessment is conducted, evaluating heavy metal leaching and the lifecycle of sludge‐based geopolymer. Finally, we briefly discuss some problems in the current research and development trends in the future on sludge‐based geopolymer. The aim of this article is to provide comprehensive support and guidance for both the research and practical engineering applications of sludge‐based geopolymer.

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“…The significant absorption band located at 1433 cm -1 is due to the CO3 -2 stretching vibrations. Meanwhile, the dispersion of atmospheric carbonate inside the composites during the ageing process produced the development of the absorption band [26]. The band at 954 cm -1 was caused by the asymmetric stretching vibrations of (Si-O-T) where (T,tetrahedal =Si or Al) [27].…”

Section: Ftir Techniquementioning

confidence: 99%

Physico-Mechanical Characteristics Of Reinforced Slag-Based Geopolymer Composites By Using Steel Fibers

et al. 2022

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A considerable portion of the CO2 emissions produced during the cement manufacturing process contribute to the greenhouse effect and the planet's warming. This prompted the quest for cement substitutes that were more environmentally friendly. Utilizing steel slag from blast furnaces or creating slag geopolymer composites are good alternatives. Despite having good compressive strength and endurance, blastfurnace steel slag in geopolymer has low flexural and tensile strength. In order to address these issues, steel fibres are introduced. This study examines the effects of adding steel fibres to slag-based geopolymer composites that have been activated by an alkaline solution of 6 % sodium hydroxide in various ratios (0.5, 1, 2, and 3 percent by weight). Compressive strength, water/binder ratio, and mechanical characteristics are described. Several methods, including X-ray diffraction and Fourier transform infrared spectra, have been used to pinpoint the phases and structural characteristics of the resulting geopolymer. The results demonstrated that adding different percentages of steel fibre up to 2 % followed by a step decrease, led to higher mechanical strength, shrinkage, water absorption, crack propagation, and post-cracking in the resulting geopolymer composites.

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Comparative mechanical and microstructural properties of high calcium fly ash one-part geopolymers activated with Na2SiO3-anhydrous and NaAlO2

Cited by 30 publications

References 45 publications

Optimization of Fly Ash—Slag One-Part Geopolymers with Improved Properties

Optimization of Fly Ash—Slag One-Part Geopolymers with Improved Properties

Sludge‐based geopolymer materials: A review

Physico-Mechanical Characteristics Of Reinforced Slag-Based Geopolymer Composites By Using Steel Fibers

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