Mechanisms of recycled fine brick aggregate in autogenous shrinkage mitigation, mechanical properties enhancement and microstructure improvement of alkali-activated slag-fly ash mortar

Tian, Lingyu; Chen, Xin; Liu, Xu; Li, Hebin; Ge, Yaojun

doi:10.1016/j.conbuildmat.2023.130755

Cited by 12 publications

(3 citation statements)

References 61 publications

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“…Lower w/b increases the OH − ion concentration. Consequently, the rate of breaking the Ca-O, Si-O-Si, and Al-O-Al bonds is sped up, which leads to the increase in Ca 2+ ion concentration and accelerates the formation of hydration products and the arrival of the initial setting state [20,46,47]. However, the water absorption of mud also delays the hydration process, especially with high kaolinite content [48][49][50][51], leading to a longer final setting time.…”

Section: Se Ing Timementioning

confidence: 99%

“…However, the water absorption of mud also delays the hydration process, especially with high kaolinite content [48][49][50][51], leading to a longer final setting time. As for the effect of the particle sizes of mud on setting time, the capability of liquid absorption of clay with a smaller particle size is stronger than that of silt with a larger particle size [46]. Therefore, the initial setting time of AAS containing clay is shorter, and the final setting time is longer.…”

Section: Se Ing Timementioning

confidence: 99%

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Effects of Mud Content on the Setting Time and Mechanical Properties of Alkali-Activated Slag Mortar

Chen²,

Jia

et al. 2023

Materials

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High mud content in the sand has a negative impact on cement mortar but there is little research on Alkali-activated slag (AAS) mortar. In order to explore the impacts of mud content in the sand on the performance of AAS mortar, this paper used sand that contains silt, clay, and a mixture of silt and clay; tested the setting time of AAS with different mud contents of 0%, 2%, 4%, 6%, 8%, and 10%; and measured the unconfined compressive strength and beam flexural strength of 3 d, 7 d, and 28 d AAS mortar specimens. The microstructure of AAS mortar with different kinds of mud was observed by scanning electron microscope (SEM), the elemental composition of the hydration product was tested by energy dispersive spectroscopy (EDS), and the AAS interaction mechanism with different kinds of mud was analyzed. The main conclusions are: the higher the mud content in the sand, the shorter the initial setting time and the longer the final setting time of AAS, mainly because the mud in the sand affects the hydration process; mud content above 4% causes a rapid decrease in the compressive and flexural strengths of AAS mortar, mainly because the mud affects the hydration process and hinders the bonding of the hydration product with the sand. When there is no mud in the sand, the main hydration product of AAS is dense calcium-alumina-silicate-hydrate (C-A-S-H) gel. When the sand contains silt, the hydration product of AAS is loose C-A-S-H gel. When the sand contains clay, the hydration products of AAS contain C-A-S-H gel and a small amount of sodium-aluminum-silicate-hydrate (N-A-S-H), and needle-like crystals. Loose gel and crystals have a negative effect on the AAS mortar strength.

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Section: Se Ing Timementioning

confidence: 99%

Section: Se Ing Timementioning

confidence: 99%

Effects of Mud Content on the Setting Time and Mechanical Properties of Alkali-Activated Slag Mortar

Chen²,

Jia

et al. 2023

Materials

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“…Nevertheless, geopolymer composites can have their thermal behavior engineered and optimized with the reinforcement of the resulting microstructure with organic or inorganic fibers, inorganic fillers, etc. [6,[8][9][10][11][12][13]. For example, Hemra and Aungkavattana [12] reported that 50 wt% of cordierite addition to a metakaolin-based matrix resulted in specimens with improved thermo-mechanical properties, as the prepared compositions kept their compressive strength values (19.8 MPa) even after 15 thermal shock cycles.…”

Section: Introductionmentioning

confidence: 99%

Recycling of roof tile waste in the manufacturing of high-temperature metakaolin-based geopolymer composites

Bezerra,

Soares,

Morelli

et al. 2023

Cerâmica

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The possibility of recycling solid wastes in the production of geopolymers and advanced ceramic products has received special attention recently. This work investigated the feasibility of replacing a high amount (70-90 wt%) of metakaolin with roof tile waste (CW) in the production of Na-geopolymer composites. Additionally, the influence of this alternative material, in the phase transformations and properties evolution (elastic modulus, compressive strength, porosity, density, and linear shrinkage) of the prepared compositions after distinct thermal treatments (40-1000 °C) was evaluated. The results showed that the incorporation of CW powder into the geopolymeric compositions enhanced their thermal and mechanical properties up to 1000 °C. The best performance was reached when using 80 wt% of the selected waste, which led to ceramic specimens with high crystallinity (presenting quartz, hematite, and albite phases), compressive strength (39.6 MPa), suitable linear shrinkage (-7.4%), and improved thermal stability (without visual cracks) after firing at 1000 °C.

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Characteristics of carbide-slag-activated GGBS–fly ash materials: Strength, hydration mechanism, microstructure, and sustainability

Li,

Wang,

Wei

et al. 2024

Construction and Building Materials

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Mechanisms of recycled fine brick aggregate in autogenous shrinkage mitigation, mechanical properties enhancement and microstructure improvement of alkali-activated slag-fly ash mortar

Cited by 12 publications

References 61 publications

Effects of Mud Content on the Setting Time and Mechanical Properties of Alkali-Activated Slag Mortar

Effects of Mud Content on the Setting Time and Mechanical Properties of Alkali-Activated Slag Mortar

Recycling of roof tile waste in the manufacturing of high-temperature metakaolin-based geopolymer composites

Characteristics of carbide-slag-activated GGBS–fly ash materials: Strength, hydration mechanism, microstructure, and sustainability

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