Using calcium carbide residue to prepare ecological alkali activated slag composites: Effect of anion type

Zhao, Yunqi; Gu, Xiaowei; Xu, Xiaochuan; Zhang, Zaolin

doi:10.1016/j.ceramint.2023.05.039

Cited by 13 publications

(5 citation statements)

References 94 publications

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“…The excess CMTs particles seemed to limit the growth of the hydration gel, leading to poorer continuity and more microdefects in the sample, hence exhibiting lower compressive strength. The Ca/Si atomic ratio of the hydration products of sample S50F30C20 were calculated to be in the range of 1.8 to 2.3, which was slightly higher than the data reported in existing studies [50,55]. The Ca/Si atomic ratio of the hydration products in sample S50F50C0 was 0.8, which was consistent with the data from current research.…”

Section: Sem/eds Analysissupporting

confidence: 87%

“…Figure 11 presents the EDS results of the elements Ca, Si, Mg, Al, Fe, and O in the sample S50F30C20 from Figure 10d. The composition of the elements Ca, Si, Mg, Al, Fe, and O in the microstructure of the sample S50F50C0 from Figure 10a is shown in Figure 12.The Ca/Si atomic ratio of the hydration products of sample S50F30C20 were calculated to be in the range of 1.8 to 2.3, which was slightly higher than the data reported in existing studies[50,55]. The Ca/Si atomic ratio of the hydration products in sample S50F50C0 was 0.8, which was consistent with the data from current research.…”

mentioning

confidence: 60%

“…The main mineral phases in sample S50F50C0 were ettringite, quartz, C(-N)-S-H gel, and calcite [49], while the samples with added CMTs exhibit the presence of the complex salt phase CaNa2(CO3)2. Gaylussite (CaNa2(CO3)2⋅5H2O) could be observed in the XRD pattern at approximately 2θ = 36.2° [50]. The presence of gaylussite implies the dissolution of Ca 2+ from CMTs under alkaline conditions, suggesting that hydration of CMTs may occur in the presence of alkali.…”

Section: Xrd Analysismentioning

confidence: 99%

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Utilization of Copper–Molybdenum Tailings to Enhance the Compressive Strength of Alkali-Activated Slag-Fly Ash System

Wang,

Gu,

Wang

et al. 2024

Buildings

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Utilizing a variety of solid wastes to prepare alkali-activated cementitious materials is one of the principal trends in the development of cementitious materials. Commonly used alkali activation precursors such as granulated blast furnace slag (GBFS) and fly ash (FA) will be less available due to resource pressures. Supply limitation is an important reason to research alternative precursors. To realize the high value-added utilization of copper–molybdenum tailings (CMTs), this study adopted the modified sodium silicate solution as an alkaline activator to activate GBFS-FA-CMTs cementitious system to prepare alkali-activated cementitious materials. The influence of CMTs content on the compressive strength of GBFS-FA-CMTs cementitious system was analyzed, and the mechanism of GBFS-FA-CMTs cementitious system was also analyzed through hydration product types, physical phase composition, and microscopic morphology. The results indicated that a paste with the incorporation of CMTs, S50F30C20 (50% GBFS, 30% FA, 20% CMTs), achieved the highest compressive strength of 79.14 MPa, which was due to the filling effect of the CMTs and the degree of participation in the reaction. Pastes with different contents of CMTs, while maintaining a constant CBFS content, exhibited similar strength development. Excessive amounts of CMTs could result in reduced compressive strength. Microstructural analysis revealed that the hydration products were structurally altered by the addition of CMTs. In addition to ettringite, quartz, C(-N)-S-H gel, and calcite, gaylussite was also formed; moreover, the mass of chemically bound water increased, and the microstructure of reaction products became denser. An excess of CMTs may restrict the growth of the hydration gel, leading to more microstructural defects. The study suggests that CMTs could enhance the compressive strength of hardened paste within an alkali-activated slag-fly ash system, possibly due to a filling effect and participation in the chemical reaction. This research confirms the feasibility of using CMTs in alkali-activated cementitious materials.

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Section: Sem/eds Analysissupporting

confidence: 87%

mentioning

confidence: 60%

Section: Xrd Analysismentioning

confidence: 99%

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Utilization of Copper–Molybdenum Tailings to Enhance the Compressive Strength of Alkali-Activated Slag-Fly Ash System

Wang,

Gu,

Wang

et al. 2024

Buildings

Self Cite

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“…Numerous studies have shown that cementitious materials have a complex spatial structure and uneven pore distribution [58][59][60][61], The pore distribution and total porosity of the samples with different mixing ratios were tested by MIP at 28 d, and the results are shown in Figure 8. According to the results of academician Zhongwei Wu, all pores are classified into four types: pores with diameters less than 20 nm are considered to be harmless pores, produced by gel pores with a C-S-H interlayer structure [62][63][64][65]: less hazardous pores (d = 20~100 nm); more hazardous pores (d = 100~200 nm); and more hazardous pores, with diameters more than 200 nm.…”

Section: Mercury Impression Test (Mip)mentioning

confidence: 99%

Experimental Study on the Properties and Hydration Mechanism of Gypsum-Based Composite Cementitious Materials

Liu,

Song,

et al. 2024

Buildings

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In order to achieve the resourceful, large-scale and high-value utilization of bulk industrial solid wastes such as flue gas desulfurization gypsum (FGDG), fly ash (FA) and ground blast furnace slag (GGBS), and to reduce the dosage of cementitious materials, orthogonal experimental methods were used to prepare composite cementitious materials based on the principle of synergistic coupling and reconstruction of multi-solid wastes. Through the method of extreme difference and ANOVA, the influence law of different factor levels on the performance of the cementitious materials was studied, and the maximum compressive strength of cementitious materials was reached when the ordinary Portland cement (OPC) dosage was 20%, the FGDG dosage was 56%, the FA dosage was 19.2% and the slag dosage was 4.8%, and the W/B was 0.55. The hydration products and microscopic morphology of the cementitious materials were analyzed by means of XRD, SEM and MIP techniques, so as to elucidate the complex synergistic hydration mechanism, and then to determine the more optimal group distribution ratio. The results show that the hydration reaction between FGDG and OPC can be synergistic with each other, and C-A-H further generates AFt under the action of SO42−, and at the same time, it plays the role of alkali-salt joint excitation for FA–GGBS, generates a large amount of cementitious materials, fills up the pores of the gypsum crystal structure, and forms a dense microstructure.

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“…Numerous studies have demonstrated that CS possesses a certain alkali excitation effect. The combination of CS and GBFS yields the best effect, but adding some auxiliary material is often required to obtain ideal strength [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

Liang,

Liu,

Jing

et al. 2024

Applied Sciences

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Industrial solid waste is characterized by complex mineral phases and various components. Low-carbon cementitious materials can be prepared through precise regulation based on the material composition and properties of various industrial solid wastes. In this study, electrolytic manganese residue (EMR), carbide slag (CS), and granulated blast-furnace slag (GBFS) were used as alternatives to cement to prepare multicomponent solid waste cementitious materials. The effects of the proportions of EMR and CS on the cementitious activity of GBFS and the activation mechanism of alkali and sulfur were studied. The results showed that with increasing EMR content, the strength first increased and then decreased. At a GBFS content of 20%, CS content of 2%, and EMR content of 8%, the compressive strength was highest, reaching 45.5 MPa after 28 days of curing, mainly because the OH− in CS and SO42− in EMR synergistically stimulated the active components in GBFS. Hydrated products such as ettringite and hydrated calcium silicate (C–S–H gel) were generated and interlaced with each other to improve the densification of the mortar. Overall, the proposed system provides an avenue to reduce or replace the production of cement clinker and achieve the high-value-added utilization of industrial solid waste.

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Using calcium carbide residue to prepare ecological alkali activated slag composites: Effect of anion type

Cited by 13 publications

References 94 publications

Utilization of Copper–Molybdenum Tailings to Enhance the Compressive Strength of Alkali-Activated Slag-Fly Ash System

Utilization of Copper–Molybdenum Tailings to Enhance the Compressive Strength of Alkali-Activated Slag-Fly Ash System

Experimental Study on the Properties and Hydration Mechanism of Gypsum-Based Composite Cementitious Materials

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

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