Effect of Activated Coal Gangue in North China on the Compressive Strength and Hydration Process of Cement

Zhou, Shan; Dong, Jicheng; Yu, Lehua; Xu, Changjie; Jiao, Xiangke; Wang, Meiying

doi:10.1061/(asce)mt.1943-5533.0002643

Cited by 32 publications

(6 citation statements)

References 18 publications

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“…The strong absorption band at 1091 cm −1 corresponds to the antisymmetric stretching vibration of Si–O, whereas the peaks at 797, 778, and 695 cm −1 indicate the presence of the Si–O–Si bond of quartz 87,88 . The band at 797 cm −1 can also be attributed to the vibration of sixfold coordinated Al–O, which suggests that the raw powder contains octahedral six‐coordinate AlO 6 89 …”

Section: Resultsmentioning

confidence: 99%

“…[84][85][86] The strong absorption band at 1091 cm −1 corresponds to the antisymmetric stretching vibration of Si-O, whereas the peaks at 797, 778, 87,88 The band at 797 cm −1 can also be attributed to the vibration of sixfold coordinated Al-O, which suggests that the raw powder contains octahedral six-coordinate AlO 6 . 89 After the alkali activation reaction, the sample shows bands at 3594 and 1671 cm −1 , which are attributed to O-H from adsorbed atmospheric water 61 . In addition, the peak at 1452 cm −1 is assigned to the O-C-O stretching of sodium carbonate formed by the reaction between sodium silicate F I G U R E 3 (A) Total porosity and compression strength of the porous specimens (S0-S5); (B) the compression strength and the total porosity data of this study (samples S0-S5) (•) and previous data 25,34,35,60,91,[98][99][100][101] for high-porosity (>85%) samples prepared by different preparation methods.…”

Section: X-ray Diffraction and Infrared Spectroscopy Analysismentioning

confidence: 99%

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Porous alkali‐activated material from hypergolic coal gangue by microwave foaming for methylene blue removal

Liu

Bai

et al. 2022

J Am Ceram Soc.

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Overall, 100% hypergolic coal gangue (HCG)‐based geopolymer foams were produced by a novel saponification‐microwave foaming combined route. Microwave foaming with and without expired vegetable oil was first used to produce CG‐based geopolymer foams. Macropores were mainly generated by microwave foaming, and mesopores were mainly obtained by the addition of expired soybean oil that underwent a saponification reaction. The effects of the oil content on the density, porosity, pore morphology, compression strength, and methylene blue adsorption properties were studied. High total porosity (85.9–89.0 vol%) and acceptable compression strength (0.46–1.1 MPa) HCG‐based geopolymer foams were produced. Foams with 12.59 wt% oil exhibited the best adsorption properties, with an adsorption capacity up to 9.4 mg/g and high removal efficiency of about 95.3%. These solid‐waste‐based porous components are promising monolithic adsorbents for wastewater treatment.

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Section: Resultsmentioning

confidence: 99%

Section: X-ray Diffraction and Infrared Spectroscopy Analysismentioning

confidence: 99%

Porous alkali‐activated material from hypergolic coal gangue by microwave foaming for methylene blue removal

Liu

Bai

et al. 2022

J Am Ceram Soc.

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“…Zhang et al [31] found a thermal temperature of 800 • C was suitable for the pozzolanic reactivity of CG, and the calcined CG prepared geopolymers have good performance. As the temperature reached 900 • C, the mechanical properties of CG-based geopolymers decreased, as reported by Zhou et al [32]. Li et al [20] discussed the effects of CG particle size on the compressive strength of geopolymers and the results showed that the 200 mesh of CG could obtain the desired compressive strength for geopolymers.…”

Section: Introductionmentioning

confidence: 62%

Geopolymerization of Coal Gangue via Alkali-Activation: Dependence of Mechanical Properties on Alkali Activators

Wang,

Liu,

Pan

et al. 2024

Buildings

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Coal gangue (CG) is a residual product from coal mining and washing processes. The reutilization of CG to produce geopolymers is a low-carbon disposal strategy for this material. In this study, the calcined CG (CG700°C) was used as aluminosilicate precursors, and the effects of alkali activators (i.e., Na2SiO3/NaOH, NaOH concentration, and liquid–solid) on the mechanical characteristics and microstructure of CG700°C-based geopolymers were investigated. The findings indicated that the specimens with a liquid–solid ratio of 0.50 (G2.0-10-0.50) exhibited a compact microstructure and attained a compressive strength of 24.75 MPa. Moreover, increasing the Na2SiO3/NaOH mass ratio has shortened the setting times and facilitated geopolymer gel formation, resulting in a denser microstructure and improved compressive strength. The higher NaOH concentrations of alkali activators facilitated the dissolution of CG700°C particles, and the geopolymerization process was more dependent on the condensation of SiO4 and AlO4 ions, which promoted the formation of geopolymer networks. Conversely, an increase in the liquid–solid ratio from 0.50 to 0.65 had a negative impact on compressive strength enhancement, impeding the polycondensation rate. Examination through scanning electron microscopy and mercury intrusion porosimetry revealed that employing a lower Na2SiO3/NaOH mass ratio (G1.2-10-0.55), smaller NaOH concentrations (G2.0-8-0.55), and a higher liquid–solid ratio (G2.0-10-0.65) led to the presence of larger pores, resulting in decreased 28 days compressive strength values (15.87 MPa, 13.25 MPa, and 14.92 MPa, respectively), and a less compact structure. The results suggest that the performance of CG700°C-based geopolymers is significantly influenced by alkali activators.

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“…Therefore, only a little amount of acicular ettringite was observed on the fracture surface. Other research works also found that metakaolin with high activity could promote the hydration process of Portland cement by formation of more C 3 AH 6 [25,26]. However, after cialcined at higher temperatures of 800 °C-1000 °C, the crystallization degree of metakaolin was increased with calcining temperature rising, metakaolin with low activity was not only incapable of producing sufficient C 3 AH 6 for hydration process of Portland cement but also counterproductive to the transformation of Aft to AFm due to its obstruction in the mortar.…”

Section: Fracture Surfaces Analysis Of Mortar Specimensmentioning

confidence: 88%

Thermal activation and mechanical properties of high alumina coal gangue as auxiliary cementitious admixture

Zhang,

Li,

Yang

et al. 2024

Mater. Res. Express

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In order to use high alumina coal gangue as auxiliary cementitious admixture via a simple and convenient thermal activation technique, the thermal transformation, mineral phase transformation and structure changes of coal gangue at calcining temperatures of 500-1000oC were analyzed using X-ray diffraction (XRD), differential thermal Analysis (DTA), thermogravimetry (TG), infrared analysis (IR) and scanning electron microscope (SEM). The mechanical properties of cement mortar with 30% coal gangue auxiliary cementitious admixture were also measured to determine the optimal calcining temperature. As calcining temperature was increased, the coal gangue experienced the following transformations: carbon combustion, dehydroxylation, metakaolin transformation and mullite transformation. The cement mortar with coal gangue auxiliary cementitious admixture calcined at 700oC presented the highest 28-d flexural and compressive strength, increasing by 8.27% and 11.85% respectively as compared with the benchmark cement mortar. The maximum dosage of coal gangue auxiliary cementitious admixture in cement mortar was further identified to be less than 30% by mechanical properties testing. The activity of high alumina coal gangues at different calcining temperatures was explained from the view points of hydration degree and products. The present investigation can provide a useful reference to utilize high alumina coal gangue as auxiliary cementitious admixture by means of a simple thermal activation at 700oC.

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Effect of Activated Coal Gangue in North China on the Compressive Strength and Hydration Process of Cement

Cited by 32 publications

References 18 publications

Porous alkali‐activated material from hypergolic coal gangue by microwave foaming for methylene blue removal

Porous alkali‐activated material from hypergolic coal gangue by microwave foaming for methylene blue removal

Geopolymerization of Coal Gangue via Alkali-Activation: Dependence of Mechanical Properties on Alkali Activators

Thermal activation and mechanical properties of high alumina coal gangue as auxiliary cementitious admixture

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