Influence of Different Parameters on the Performance of Alkali-Activated Slag/Fly Ash Composite System

Zhang, Zhipeng; Jia, Yanmin; Liu, Jinliang

doi:10.3390/ma15082714

Cited by 3 publications

(4 citation statements)

References 27 publications

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“…The flow test values for the produced composites indicate that the addition of both water and zinc oxide increases the fluidity of the mixtures, which was also confirmed by the research of Zhang et al [ 23 ], who studied the effect of various parameters on alkali-activated slag/fly ash composites. They observed that fluidity increased with increasing fly ash content in the mixture.…”

Section: Discussionsupporting

confidence: 73%

Alkali-Activated Materials Doped with ZnO: Physicomechanical and Antibacterial Properties

Ślosarczyk,

Klapiszewska,

Parus

et al. 2023

Materials

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The requirements related to reducing the carbon footprint of cement production have directed the attention of researchers to the use of waste materials such as blast-furnace slag or fly ashes, either as a partial replacement for cement clinker or in the form of new alternative binders. This paper presents alkali-activated materials (AAMs) based on blast-furnace slag partially replaced with fly ash, metakaolin, or zeolite, activated with water glass or water glass with a small amount of water, and doped with zinc oxide. The mortars were tested for flow, hydration heat, mechanical strength, microstructure, and antimicrobial activity. The obtained test results indicate the benefits of adding water, affecting the fluidity and generating a less porous microstructure; however, the tested hydration heat, strength, and antibacterial properties are related to more favorable properties in AAMs produced on water glass alone.

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Section: Discussionsupporting

confidence: 73%

Alkali-Activated Materials Doped with ZnO: Physicomechanical and Antibacterial Properties

Ślosarczyk,

Klapiszewska,

Parus

et al. 2023

Materials

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“…The main reasons for the inhibition of AASRSS hydration by NaSt are as follows: (1) NaSt adsorbs on the surface of silica-aluminate precursor particles, which prevents the precursor and alkali activator from reacting in contact with each other [24]. (2) The wrapping effect of NaSt on the solution in the slurry reduces the liquid-phase distribution of the system to some extent, resulting in a reduction in the contact area between the precursor particles and the alkali activator [26]. To further explore the mechanisms behind these findings of compressive strength and water sorptivity, the reaction process, reaction products and pore structure were carefully examined, and the results are presented in the following sections.…”

Section: Isothermal Calorimetrymentioning

confidence: 99%

Section: Isothermal Calorimetrymentioning

confidence: 99%

Effect of Sodium Stearate on the Microstructure and Hydration Process of Alkali-Activated Material

Yao,

Li,

Chen

et al. 2023

Applied Sciences

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In response to the high water sorptivity of alkali-activated slag–red mud–steel slag cementitious material (AASRSS), water and aggressive ions are easily transferred to the interior of cementitious materials, which poses a significant threat to their durability. In order to limit the transfer of moisture and aggressive ions to the interior of AASRSS, sodium stearate (NaSt) was utilized in this paper to reduce its water sorptivity. The aim of this study was to elucidate the role of NaSt in the AASRSS system. The changes in the compressive strength and water sorptivity of AASRSS mortar were tested by mixing different amounts of NaSt into the mortar. The changes in the hydration process and microstructure of AASRSS after mixing with NaSt were analyzed by using the test methods of the isothermal calorimetry, resistivity, SEM and MIP. The results showed that NaSt plays an important role in the pore structure characteristics of AASRSS and that the use of NaSt significantly reduces its water sorptivity. The improvement in the water sorptivity was caused by two main mechanisms, namely the optimization of the pore structure (reduction in defects of the microstructure and alteration of pore size distribution) and the introduction of a hydrophobic film on the pore surface. The addition of NaSt did not change the type of AASRSS hydration product, but it inhibited the hydration reaction, leading to a reduction in the hydration product. The combination of the increased porosity and reduced hydration products mainly accounts for the decrease in the compressive strength of AASRSS due to NaSt.

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“…This is because when the dosage of sodium silicate is 50 g, the concentration of OH − in the system is low, the erosion of precursor is slow, and the slurry is mainly manifested as the highly viscous sodium silicate aqueous solution and suspended particle mixture. At this point, if the content of sodium silicate is slightly increased, the concentration of OH − is enough to erode the precursor, while if the content of sodium silicate continues to increase, excessive OH − will form Ca (OH) 2 with Ca 2+ , inhibiting an increase in the fluidity [38].…”

Section: Workabilitymentioning

confidence: 99%

Effect of Solid Sodium Silicate on Workability, Hydration and Strength of Alkali-Activated GGBS/Fly Ash Paste

Dong

Sun

et al. 2023

Coatings

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Based on economic and environmental considerations, the recycling economy of mineral waste has been found to have great potential and economic benefits worldwide, in which alkali-activated cementitious materials are one of the main developing directions. The alkali activators commonly used in alkali-activated cementitious materials are the composite activators of sodium silicate solution and solid sodium hydroxide, which not only need to deal with high viscosity and corrosive chemicals, but also need to be prepared in advance and properly stored. In this paper, ground granulated blast furnace slag (GGBS) and fly ash were used as precursors, while solid sodium silicate powder was applied as the alkali activator. In addition, the precursors were mixed with the activator in advance and activated by adding water to prepare alkali-activated GGBS/fly ash cement. The influence of precursor components, the dosage of the alkali activator and the liquid–solid ratio on the working performance, mechanical strength and hydration process of alkali-activated cement was studied. The results showed that the further incorporation of GGBS accelerated the alkali activation reaction rate and improved the strength of the specimen. However, in the specimen with GGBS as the main component of the precursor, the main hydration product was C-A-S-H gel, which was different in the structural order and quantity. The compressive strength indicated that there was the best amount of activator to match it in terms of the precursor with certain components. A too high or too low amount of activator will hinder the alkali activation reaction. This study can provide some significant reference material for the use of solid alkali activators in alkali-activated cementitious materials.

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Influence of Different Parameters on the Performance of Alkali-Activated Slag/Fly Ash Composite System

Cited by 3 publications

References 27 publications

Alkali-Activated Materials Doped with ZnO: Physicomechanical and Antibacterial Properties

Alkali-Activated Materials Doped with ZnO: Physicomechanical and Antibacterial Properties

Effect of Sodium Stearate on the Microstructure and Hydration Process of Alkali-Activated Material

Effect of Solid Sodium Silicate on Workability, Hydration and Strength of Alkali-Activated GGBS/Fly Ash Paste

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