On the quantification of degrees of reaction and hydration of sodium silicate-activated slag cements

Park, Solmoi; Abate, Selamu Yihune; Lee, Hyo Kyoung; Kim, Hyeong-Ki

doi:10.1617/s11527-020-01505-9

Cited by 9 publications

(5 citation statements)

References 33 publications

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“…16f. It can be found that the reaction degree of slag is increased steadily from 25.19% to 61.31% between 1 d and 28 d. This is consistent with the result reported in literature that the reaction degree of slag at 28 d can reach around 60% [61,62]. Nevertheless, its reaction rate is decreased dramatically from 25.19%/d to 6.63%/d between first curing stage (0 -1 d) and second curing stage (1 -3 d), followed by a continuous reduction to 0.59%/d at the last stage (7 -28 d), which suggests that the early formation of inner products at 1 d would influence the reaction rate at later curing ages.…”

Section: Microstructure Evolution With Curing Agesupporting

confidence: 92%

In-situ X-ray tomographic imaging of microstructure evolution of fly ash and slag particles in alkali-activated fly ash-slag paste

Fang

Wang

Zhang

2021

Composites Part B: Engineering

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Section: Microstructure Evolution With Curing Agesupporting

confidence: 92%

In-situ X-ray tomographic imaging of microstructure evolution of fly ash and slag particles in alkali-activated fly ash-slag paste

Fang

Wang

Zhang

2021

Composites Part B: Engineering

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“…Based on the TGA thermograms all samples were stable up to 200 • C. At the range of 200-230 • C, the recast Nafion ® membrane shows the sharp drop pattern on the weight loss, while the other Nafion ® /ionic liquid remained stable. This indication of the first stage of weight loss, below 250 • C is attributed primarily to the evaporation of water molecules [23]. This proves that the incorporation of ionic liquids can improve the membrane thermal resistance to temperature variations.…”

Section: Tga Analysismentioning

confidence: 58%

“…This is because the anti-sulfonation active ionic bonds that occur between the Nafion ® molecule on the membrane at active site Bronsted acid and base along with sulfonation on Nafion ® bond began to unravel [24]. After the sudden drop, all the membranes show a slight decline before stabilizing at 400-450 • C. This upgrade may be due to the interaction between the polymer sulfonic acid and hydroxyl group, which enhances the membrane heat resistance and reduces the rate of decomposition [23].…”

Section: Tga Analysismentioning

confidence: 99%

“…The next stage involved increasing the temperature beyond 450 • C, correlating to the degradation of the polymer backbone [23,24]. At this stage, all the membranes showed severe weight loss and stabilized afterwards at 500 • C. At 600 • C, all the membrane had decomposed, and the remaining mass was different across all samples.…”

Section: Tga Analysismentioning

confidence: 99%

“…The IEC analysis was carried out to identify the concentration of free charge carriers in the membrane, meanwhile the water uptake and swelling analyses were to test the capabilities of membrane in water [23,26]. The results of these analyses for the recast Nafion ® , Nafion ® /2-HEAF and Nafion ® /PAN membrane are tabulated in Table 2.…”

Section: Iec Water Uptake and Swellingmentioning

confidence: 99%

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Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications

et al. 2021

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The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.

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Comparison of thermogravimetry response of alkali-activated slag and Portland cement pastes after stopping their hydration using solvent exchange method

Bílek,

Švec,

Másilko

et al. 2024

J Therm Anal Calorim

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The critical step for any subsequent instrumental analysis of cementitious binders is to stop their hydration reactions, i.e., to remove free water. One of the most available techniques is a solvent exchange method. However, the solvents are known to be strongly bound in ordinary Portland cement (OPC) paste and alter the results of thermogravimetric analysis (TGA) and sensitive hydrates, while their effect on TGA response of alkali-activated slag (AAS) has not been comprehensively investigated. Therefore, the objective of this paper is to track the effects of fundamental aspects of the solvent exchange on the TGA response of AAS with different sodium activators (hydroxide, carbonate, waterglass) and to support these results by X-ray diffraction and effluent gas analysis. All solvents used (acetone, diethyl ether, isopropyl alcohol, ethanol, and methanol) affected the TGA response of all tested pastes, and their effect was enhanced by prolonged immersion time. All solvents induced an additional mass loss at around 800 °C and, especially for OPC paste, increased in situ carbonation, even in an inert atmosphere. Methanol and ethanol had a detrimental effect on ettringite and decreased the basal distance of the C–(A)–S–H gel, while they only marginally affected gaylussite. For AAS, hydration stoppage by washing out the alkali-rich pore solution with water was also investigated and can usually be recommended (except for its detrimental effect on gaylussite), as it is more efficient than organic solvents, which lack solubility for activators. Methanol and ethanol are the most suitable alternatives, particularly for NaOH.

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On the quantification of degrees of reaction and hydration of sodium silicate-activated slag cements

Cited by 9 publications

References 33 publications

In-situ X-ray tomographic imaging of microstructure evolution of fly ash and slag particles in alkali-activated fly ash-slag paste

In-situ X-ray tomographic imaging of microstructure evolution of fly ash and slag particles in alkali-activated fly ash-slag paste

Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications

Comparison of thermogravimetry response of alkali-activated slag and Portland cement pastes after stopping their hydration using solvent exchange method

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