Optimization of compressive strength of fly ash-based geopolymers using central composite design

Moutaoukil, Ghizlane; Alehyen, Saliha; Sobrados, Isabel; Fadil, Mohamed El; Taïbi, M.

doi:10.1007/s12034-021-02424-3

Cited by 5 publications

(4 citation statements)

References 49 publications

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“…The CCD approach was used to evaluate the individual and synergistic effects of three components with three levels on a particular response. This technique can decrease the number of experiments required to determine the major effect and interactions of each [48,49]. Table 4 presents the boundaries of the selected factors; polypropylene fiber (PPF), nano silica (NS), and nano alumina (NA).…”

Section: Design and Methodsmentioning

confidence: 99%

Performance of Fiber-Reinforced Alkali-Activated Mortar with/without Nano Silica and Nano Alumina

2022

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The current study is aimed to evaluate the effect of nanomaterials (nano alumina (NA) and nano silica (NS) on the mechanical and durability performance of fiber-reinforced alkali-activated mortars (FRAAM). Polypropylene fiber (PPF) was added to the binders at 0.5% and 1% of the volume of the alkali-activated mortar (AAM). Design-expert software was used to provide the central composite design (CCD) for mix proportions. This method categorizes variables into three stages. The number of mixes was created and evaluated with varied proportions of variables. The primary binders in this experiment were 50% fly ash (FA) and 50% ground granulated blast slag (GGBS). The alkali-activated solution to binder ratio was 0.5, and the sodium hydroxide (NaOH) concentration was 12 molarity. The sodium silicate to sodium hydroxide ratio was 2.5. The cubic specimens and prisms were evaluated in an ambient atmosphere at 23 + 3 °C room temperature at the ages of 7 and 28 days. The mechanical performance of AAM was indicated through evaluation of the compressive and flexural strength, flowability, and unit weight of the alkali activator mortar. In addition, the durability performance and microstructure analysis were also evaluated. The experiments demonstrated that the AAM without fibers and nanomaterials had a higher flow rate than the other mixtures. However, the flowability of all mixtures was acceptable. The highest compressive strength was deducted through the use of 2% NA and higher flexural tensile strength was obtained for mixtures included 1% NS and 0.5% PPF. The lower water absorption was noted through the combination of 2% nano silica and 1% polypropylene fiber. Whereas, the combination of 2% nano silica, 1% nano alumina, and 0.5% polypropylene fiber had the lower sorptivity. In addition, the microstructure analysis indicated that the nanomaterials significantly improved the matrix and the porosity of the matrix was considerably reduced.

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Section: Design and Methodsmentioning

confidence: 99%

Performance of Fiber-Reinforced Alkali-Activated Mortar with/without Nano Silica and Nano Alumina

2022

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“…In this study, three common foaming agents were used: aluminum powder [26,27,31,32], zinc powder [28,33,34], and hydrogen peroxide [28,32,[35][36][37]. Aluminum powder is favored for its ability to release hydrogen gas upon reacting with alkaline solutions, contributing to lightweight foam with interconnected voids.…”

Section: Methodsmentioning

confidence: 99%

“…The formulation selection was based on extensive research conducted in our previous studies. In these studies, we focused on optimizing various parameters, including the initial ratios of fly ash (FA) to alkaline solution, and the ratio of sodium silicate to sodium hydroxide [33], as well as the type of alkaline solution and curing conditions [34,35]. Through systematic experimentation and analysis, we identified the optimum formula that yielded the desired properties for geopolymer foam production, encompassing mechanical, microstructural, and thermal aspects [36].…”

Section: Methodsmentioning

confidence: 99%

Monitoring the Geopolymerization Reaction of Geopolymer Foams Using 29Si and 27Al MAS NMR

Moutaoukil,

Sobrados,

Alehyen

et al. 2024

Minerals

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This study aims to investigate the geopolymerization reaction of geopolymer foams produced with three different foaming agents: aluminum powder, zinc powder, and hydrogen peroxide. The geopolymerization reaction of geopolymer foam was monitored using the 27Al and 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy technique. 27Al MAS-NMR was used to monitor the reaction at an early stage, while 29Si and 27Al MAS-NMR analyses were employed at specific time intervals of 3, 6, 10, 15, and 28 days to examine the changes that occurred in the formed gel over time. We discussed in detail how the type of foaming agent used and the duration of the reaction both influence the quantity of gel formed and the amount of remnant fly ash. Our findings indicate that the type of foaming agent used affects the formation and structure of the gel, with aluminum powder leading to the highest gel formation. Additionally, the duration of the reaction plays a significant role in determining the quantity of remnant fly ash, with longer reaction times resulting in decreased fly ash content. This study sheds light on the relevance of understanding the role of foaming agents in the geopolymerization reactions of geopolymer foams and the influence of reaction time on the formed gel properties.

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“…The CCD method was used to assess three components' individual and synergistic potential effects with three levels in one response. This method can restrict the number of tests needed to determine each variable's key effects and interactions [36,37]. Nano-silica and Nano-alumina were used at varying percentages of 1% and 2% [38,39] of the binder by weight, respectively.…”

Section: Methods and MIX Designmentioning

confidence: 99%

The Effect of Nano-Silica and Nano-Alumina with Polypropylene Fiber on the Chemical Resistance of Alkali-Activated Mortar

2022

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This study investigates the simultaneous effect of nano-silica and nano-alumina with and without polypropylene fiber on the chemical-resistant of alkali-activator mortar (AAM) exposed to (5% Sulfuric Acid, 5% Magnesium Sulphate, and 3.5% Sodium chloride) attack. Design-expert software provided the central composite design (CCD) for mixed proportions. Nano-silica (NS) and nano-alumina (NA) at 0, 1%, and 2%, and with polypropylene fiber (0, 0.5%, and 1%) were used in the production of AAM. The alkali activator mortar mixes were created using an alkaline activator to binder ratio of 0.5. The binder materials include 50% fly ash Class F (FA) and 50% ground granulated blast furnace slag (GGBS). A sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH) were combined in the alkaline activator at a ratio of 2.5 (Na2SiO3/NaOH). The mechanical properties of AAM were tested via compressive strength and flexural strength tests. The results show that the acid attack, more than the sulphate and chloride attacks, significantly influenced the AAM. The addition of both nanomaterials improved the mechanical properties and chemical resistance. The use of nanomaterials with PPF showed a superior effect, and the best results were indicated through the use of 2%NA–1%PPF.

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Optimization of compressive strength of fly ash-based geopolymers using central composite design

Cited by 5 publications

References 49 publications

Performance of Fiber-Reinforced Alkali-Activated Mortar with/without Nano Silica and Nano Alumina

Performance of Fiber-Reinforced Alkali-Activated Mortar with/without Nano Silica and Nano Alumina

Monitoring the Geopolymerization Reaction of Geopolymer Foams Using 29Si and 27Al MAS NMR

The Effect of Nano-Silica and Nano-Alumina with Polypropylene Fiber on the Chemical Resistance of Alkali-Activated Mortar

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