Influence of mechanical activation of fly ash on the properties of Portland cement mortars

Fami, Nisrine El; Ez-zaki, Hassan; Boukhari, A.; Khachani, N.; Diouri, A.

doi:10.1016/j.matpr.2022.02.340

Cited by 8 publications

(4 citation statements)

References 20 publications

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“…This can result in the reduction of the compressive strength [54]. It is important to note that higher compressive strengths are possible with higher fly ash content in cementitious composites when fly ash is mechanically activated, as shown in the outcomes of different studies [55][56][57]. Such studies are in accordance with the present investigation.…”

Section: Resultssupporting

confidence: 91%

Preparation of Green Sustainable Cement Paste Mixture Based on Inorganic Additives: An Experimental and Modelling Approach

Mahmood,

Pechočiaková,

Noman

et al. 2024

Buildings

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Using waste materials in the mixture of building materials is an approach aligned with the circular economy, a viewpoint that creates sustainable building industries, especially in developed countries. This study concentrated on the application of laponite (LAP), fly ash (FA), and bentonite (BENT) materials in the mixture of cement pastes. The first step used experimental practices to examine the metrics of toughness, three-point bending, and compressive strength with different percentages of added LAP, FA, and BENT after the characterization of samples by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The next step entailed assessment of cement paste specifications through some regressive equations obtained by the application of 2D curve fitting and sensitive analysis of additive (FA, LAP, and BENT) fluctuations in the structure of cement paste. The results show that linear polynomial equations are the best for the evaluation of cement paste terms as per different percentages of the additives. The environmental impact assessment (EIA) of nine prepared samples demonstrated that LAP created the safest condition in comparison to others. However, the ordered weighted averaging (OWA) computations applied for the sustainability assessment (SA) of the samples showed that the LAP is the most appropriate option for use in the structure of cement paste. Using experimental analysis and mathematical modeling, the behavior of cement paste interacting with mineral additives is evaluated. Sustainable mixtures are then presented based on EIA.

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Section: Resultssupporting

confidence: 91%

Preparation of Green Sustainable Cement Paste Mixture Based on Inorganic Additives: An Experimental and Modelling Approach

Mahmood,

Pechočiaková,

Noman

et al. 2024

Buildings

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“…First, such an increase in strength is determined by forming a denser structure and more hydration products due to the extremely active effect of AFA. As pointed out in [77], the mechanical activation of AFA improves particle fineness, increases silica and alumina content in the treated AFA, and increases the sample's compressive strength. When 5-10% milled FA was used [78], compressive strength was increased by 8-12%, compared to the results of untreated FA.…”

Section: Mechanical Propertiesmentioning

confidence: 78%

The Effect of Mechanical Activation of Fly Ash on Cement-Based Materials Hydration and Hardened State Properties

et al. 2023

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Fly ash from coal represents the foremost waste product of fossil fuel combustion. These waste materials are most widely utilised in the cement and concrete industries, but the extent of their use is insufficient. This study investigated the physical, mineralogical, and morphological characteristics of non-treated and mechanically activated fly ash. The possibility of enhancing the hydration rate of the fresh cement paste by replacing part of the cement with non-treated and mechanically activated fly ash, and the hardened cement paste’s structure and early compressive strength performance, were evaluated. At the first stage of the study, up to 20% mass of cement was replaced by untreated and mechanically activated fly ash to understand the impact of the mechanical activation on the hydration course; rheological properties, such as spread and setting time; hydration products; mechanical properties; and microstructure of fresh and hardened cement paste. The results show that a higher amount of untreated fly ash significantly prolongs the cement hydration process, decreases hydration temperature, deteriorates the structure and decreases compressive strength. Mechanical activation caused the breakdown of large porous aggregates in fly ash, enhancing the physical properties and reactivity of fly ash particles. Due to increased fineness and pozzolanic activity by up to 15%, mechanically activated fly ash shortens the time of maximum exothermic temperature and increases this temperature by up to 16%. Due to nanosized particles and higher pozzolanic activity, mechanically activated fly ash facilitates a denser structure, improves the contact zone between the cement matrix, and increases compressive strength up to 30%.

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“…Of the various solutions to efficiently reduce the consumption of Portland cement, its full or partial replacement with industrial wastes and cementitious materials, such as fly ash, slag, metakaolin, and silica fume, has shown promising results. In addition to alleviating the use of Portland cement, the mechanical and durability properties of construction products made with cementitious (partial replacement) or geopolymeric (full replacement) binders has been superior to those of counterparts made with cement only [6]- [11]. According to Alexander and Shashikala [11], fly ash-slag blended geopolymer mortar exhibited better resistance to acid, sulfate, and marine water attacks compared to a control mix prepared with Portland cement.…”

Section: Introductionmentioning

confidence: 99%

Effect of Type of Sand on the Flowability and Compressive Strength of Slag-Fly Ash Blended Geopolymer Mortar

Hwalla¹,

El-Hassan²,

Assaad³

et al. 2023

Proceedings of the 8th International Conference On Civil, Structural and Transportation Engineering (ICCSTE 2023)

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This paper investigates the influence of the type of fine aggregates on the properties of slag-fly ash blended geopolymer mortar. Twelve mixes were prepared with two types of sand: desert dune sand (DS) and crushed dolomitic limestone sand (CS). Different alkaline activator solution-to-binder (0.50, 0.60, and 0.65) and binder-to-sand ratios (1:2, 1:3, and 1:4) were considered to analyze their effect on the performance of the geopolymer mortar. The properties under investigation included the amount of additional water needed to maintain a flow of 150 ± 2 mm and the 7-and 14-day compressive strengths. Experimental test results showed that an increase in fine aggregates content resulted in a higher additional water demand, regardless of the type of sand used. As a result, the mortar compressive strength decreased by up to 29% compared to mixes with the lowest binder-to-sand ratios (1:2 for DS mixes and 1:3 for CS mixes). An increase in the alkaline activator solution-to-binder ratio reduced the additional water needed to satisfy the target flowability but increased the overall liquid-to-binder ratio. Meanwhile, for optimum compressive strength, DS-based mixes comprised B:S and AAS/B ratios of 1:2 and 0.60, respectively, while those of CS-based mixes were 1:3 and 0.65, respectively. Compared to mixes made with CS, those incorporating DS required the addition of more water to maintain the flowability and experienced up to 81% loss in compressive strength; still, DS-based mixes achieved 14-day compressive strengths exceeding 28 MPa. The experimental findings advocate the use of DS as fine aggregates in the production of slag-fly ash blended geopolymer mortar to be utilized in various construction applications.

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Influence of mechanical activation of fly ash on the properties of Portland cement mortars

Cited by 8 publications

References 20 publications

Preparation of Green Sustainable Cement Paste Mixture Based on Inorganic Additives: An Experimental and Modelling Approach

Preparation of Green Sustainable Cement Paste Mixture Based on Inorganic Additives: An Experimental and Modelling Approach

The Effect of Mechanical Activation of Fly Ash on Cement-Based Materials Hydration and Hardened State Properties

Effect of Type of Sand on the Flowability and Compressive Strength of Slag-Fly Ash Blended Geopolymer Mortar

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