Studying the effect of alkali dosage on microstructure development of alkali-activated slag pastes by electrical impedance spectroscopy (EIS)

Xiang, Huimin; Shi, Caijun; Liu, Xiaojin; Zhang, Zuhua

doi:10.1016/j.conbuildmat.2020.119982

Cited by 26 publications

(15 citation statements)

References 36 publications

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“…In sample G1is_6_highK, the higher concentration of Ksil contributes to better geopolymerization both directly via a higher dissolution rate of the MK and slag reagents and indirectly due to a slightly better fluidity coming from the liquid part of the Ksil, thus compensating for the adverse mixing conditions, resulting in a sample with electrical resistivity slightly higher than the matrix. For the sample G1is_6_highW in which fluidity and mixing conditions were improved via extra water addition, reactivity and geopolymerization should be similar to the matrix, even if the extra water addition increases sample porosity, which is known to decrease electrical resistivity [ 75 , 76 ], in agreement with the lower resistivity observed for sample G1is_6_highW.…”

Section: Resultsmentioning

confidence: 69%

“…For example, conductivity values reported in. [ 76 ] for Nasil-blast furnace slag samples aged 30 days are 0.02–0.05 S/m, while in. [ 77 ] for Mk-Nasil geopolymer samples, a value of 6.2·10 −3 S/m can be retrieved based on reported sample dimensions and resistance values.…”

Section: Resultsmentioning

confidence: 99%

“…In comparison, our samples exhibit conductivities ranging from 4.4–8.3·10 −4 S/m, which is about 10–100 times lower than values reported in refs. [ 76 , 77 ] and 3–6 times higher than that of chemosynthetic geopolymers in [ 78 ]. Our highest value of resistivity (2.3·10 5 ohm-cm, for G1is_6_highK) is in the same range as given by Davidovits, [ 13 ] suggesting a complete geopolymerization for this sample.…”

Section: Resultsmentioning

confidence: 99%

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Novel Magnetic Inorganic Composites: Synthesis and Characterization

et al. 2021

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The addition of magnetic particles to inorganic matrices can produce new composites exhibiting intriguing properties for practical applications. It has been previously reported that the addition of magnetite to concrete improves its mechanical properties and durability in terms of water and chloride ions absorption. Here we describe the preparation of novel magnetic geopolymers based on two different matrices (G1 without inert aggregates and G2 with inert quartz aggregates) containing commercial SrFe12O19 particles with two weight concentrations, 6% and 11%. The composites’ characterization, including chemical, structural, morphological, and mechanical determinations together with magnetic and electrical measurements, was carried out. The magnetic study revealed that, on average, the SrFe12O19 magnetic particles can be relatively well dispersed in the inorganic matrix. A substantial increase in the composite samples’ remanent magnetization was obtained by embedding in the geopolymer SrFe12O19 anisotropic particles at a high concentration under the action of an external magnetic field during the solidification process. The new composites exhibit good mechanical properties (as compressive strength), higher than those reported for high weight concretes bearing a similar content of magnetite. The impedance measurements indicate that the electrical resistance is mainly controlled by the matrix’s chemical composition and can be used to evaluate the geopolymerization degree.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Novel Magnetic Inorganic Composites: Synthesis and Characterization

et al. 2021

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“…Other authors have used the technique in materials that include carbon additions [26,27], and even it has been used for the following of mechanical loading and damage sensing [28]. After an exhaustive search in the literature, only one recent paper has been found about the use of impedance spectroscopy to study the evolution of the microstructure of alkali activated slag [29]. This paper studies up to 28 days of age the evolution of the electrical parameters in the range from 40 Hz to 35 MHz.…”

Section: Introductionmentioning

confidence: 99%

Use of Impedance Spectroscopy for the Characterization of the Microstructure of Alkali Activated SiMn Slag: Influence of Activator and Time Evolution

et al. 2022

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The impedance spectroscopy technique has been used to study the microstructure of the binder resulting from the alkaline activation of SiMn slag. Two alkaline activators were used: waterglass and NaOH. Three different concentrations were analysed for both activators: 3.0, 3.5 and 4.0% Na2O for NaOH; and 4.0, 4.5 and 5.0% Na2O for waterglass with a constant SiO2/Na2O ratio of 1.0. The time evolution of the microstructure has been followed up using the non-destructive technique of impedance spectroscopy. This technique has been proved to be effective describing the microstructural changes in alkali activated pastes, and also can help predicting the mechanical behavior of mortars. The use of the resistivity itself seems to be deficient, but the analysis of the electrical parameters calculated from the impedance spectra measured gives a complete idea of the evolution in the material.

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“…In order to study the internal formation mechanism of scale, scholars have adopted many technical methods, such as Electrochemical Impedance Spectroscopy (EIS) (Hu et al 2020), X-ray Diffraction (XRD) (Sanjuán et al 2019b), Fourier Transform Infrared spectroscopy (FTIR), Raman Spectra (RAMAN) spectroscopy (Simpson 1998), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) (Gabrielli et al 2006;Tuan et al 2015), the microscopic morphology and crystal structure of scale has been analyzed comprehensively in these studies. Under normal temperature and pressure, calcite is stable.…”

Section: Introductionmentioning

confidence: 99%

Research on performance optimization and mechanism of electrochemical water softening applied by pulse power supply

Wang

et al. 2021

Water Science and Technology

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In order to promote the application of electrochemical water softening technology in industrial circulating cooling water systems, electric field type, cathode structure and solution residence time are selected for optimization analysis of electrochemical water softening device. The experimental results show that the water softening performance per unit area of mesh cathode is better than that of plate cathode. In addition, the softening amount per unit area of the mesh cathode can be further increased when the high-frequency (HF) power supply is applied. When the HF power supply is applied, the softening amount per unit area is 158.58 g/m2·h−1 more than that the direct current power supply is applied. In order to explore the growth mechanism of calcium carbonate, micro-analysis technology and high-speed bubble photography technology are used. The results show that the bubbles escape along the longitudinal direction of the electrode plate, and the main growth direction of calcium carbonate growth is consistent with the escape direction of the bubble, that is, the bubbles grow along the longitudinal direction of the electrode plate. The special structure of the diamond-shaped mesh cathode facilitates the growth of calcium carbonate crystals.

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Studying the effect of alkali dosage on microstructure development of alkali-activated slag pastes by electrical impedance spectroscopy (EIS)

Cited by 26 publications

References 36 publications

Novel Magnetic Inorganic Composites: Synthesis and Characterization

Novel Magnetic Inorganic Composites: Synthesis and Characterization

Use of Impedance Spectroscopy for the Characterization of the Microstructure of Alkali Activated SiMn Slag: Influence of Activator and Time Evolution

Research on performance optimization and mechanism of electrochemical water softening applied by pulse power supply

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