Evaluation of the microstructure and micromechanics properties of structural mortars with addition of iron ore tailings

Almada, Bruna Silva; Neto, Gilberto Alves da Silva; Prado, Dyala Fraga do; Aguilar, Maria Teresa Paulino; Garcia, Dayana Cristina Silva; Silva, Guilherme Jorge Brigolini; Santos, White José dos

doi:10.1016/j.jobe.2022.105405

Cited by 4 publications

(4 citation statements)

References 55 publications

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“…The similarity between the groups corroborates the mechanical properties and durability indicators, for which no significant variation was identified. In fact, it is known that the interfacial transition zone is the weakest region of a cementitious composite [42], and, as there was no change, this had an impact on the non-alteration of mechanical properties and durability between the different groups, regardless of the percentage of substitution. Although the elemental compositions of the mortar specimens were strongly affected by the selection of material for analysis, it is possible to observe a reduction in the content of Ca and Fe in addition to an increase in the Si content as a consequence of the incorporation of sand and dregs.…”

Section: Mortar Specimens' Chemical and Microstructural Propertiesmentioning

confidence: 99%

“…The similarity between the groups corroborates the mechanical properties and durability indicators, for which no significant variation was identified. In fact, it is known that the interfacial transition zone is the weakest region of a cementitious composite [42], and, as there was no change, this had an impact on the non-alteration of mechanical properties and durability between the different groups, regardless of the percentage of substitution. Regarding the hydrated compounds in the cement matrix, once analyzed in the broken section, it was found that calcium hydroxide (Portlandite) was found in the samples at 10, 15, and 20%, and 30% of dregs (Figures 14 and 15), while Ref.…”

Section: Mortar Specimens' Chemical and Microstructural Propertiesmentioning

confidence: 99%

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Use of Dregs as a Replacement for Hydrated Lime in Cement Coating Mortar

et al. 2023

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The pulp and paper industry generates a significant volume of solid waste during its operations. In order to mitigate the environmental impact caused by this industry, one of its residues was applied in eco-friendly composites. Therefore, this research aims to use green liquor dregs as a partial replacement for lime in coating mortars. Hydrated lime was replaced by dregs in percentages of 10%, 15%, 20%, and 30%, and the manufactured mortar specimens were tested in terms of their flowability, air content, and specific gravity in the fresh state. In the hardened state, physical and chemical characterization was carried out to determine the influence of the introduction of the dregs on the properties of the different types of mortar. Mechanical testing of the mortar specimens’ compressive, flexural, and adhesive strengths was carried out, and scanning electron microscopy was performed to evaluate the microstructural features of the cement composites. In general, the types of mortar with dregs showed a high degree of similarity to conventional mortar in all studied aspects, including the 30% replacement group. The obtained SEM images indicated that the presence of dregs in the mortar did not change the formational mechanism of C-S-H crystals, maintaining the mechanical properties of the material even after the accelerated aging procedure was performed, reaching similar levels of flexural, compressive, and tensile bond strengths when compared to the neat mortar. Furthermore, tensile bond levels reached approximately 0.9 MPa for all the studied types of mortar, allowing the material to be used in external applications.

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Section: Mortar Specimens' Chemical and Microstructural Propertiesmentioning

confidence: 99%

“…The similarity between the groups corroborates the mechanical properties and durability indicators, for which no significant variation was identified. In fact, it is known that the interfacial transition zone is the weakest region of a cementitious composite [42], and, as there was no change, this had an impact on the non-alteration of mechanical properties and durability between the different groups, regardless of the percentage of substitution. Regarding the hydrated compounds in the cement matrix, once analyzed in the broken section, it was found that calcium hydroxide (Portlandite) was found in the samples at 10, 15, and 20%, and 30% of dregs (Figures 14 and 15), while Ref.…”

Section: Mortar Specimens' Chemical and Microstructural Propertiesmentioning

confidence: 99%

Use of Dregs as a Replacement for Hydrated Lime in Cement Coating Mortar

et al. 2023

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“…While it seems that IOTs of all particle sizes can be readily recycled into cementitious materials, the practical reuse of IOTs powder is impeded by its low reactivity within such systems. IOTs are highly crystalline, composed primarily of mineral phases like α-quartz and hematite, which have been shown to be nearly inert in many studies [13]. Although mechanical activation has been reported to enhance the pozzolanic activity of IOTs, thus improving the performance of IOT-based cementitious systems [14,15], Duarte et al [16] found that mechanically activated IOTs did not exhibit volcanic ash activity, suggesting a predominant nucleation effect.…”

Section: Introductionmentioning

confidence: 99%

The Role of Chemical Activation in Strengthening Iron Ore Tailings Supplementary Cementitious Materials

Hu,

Gu,

Cheng

et al. 2024

Buildings

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The preparation of iron ore tailings (IOTs) into supplementary cementitious materials (SCMs) is an effective approach to achieve value-added utilization of industrial solid waste. This study systematically investigates the hydration pattern and strength development of Portland cement systems with the incorporation of IOTs, steel slag (SS), granulated blast-furnace slag (GBFS), and fly ash (FA) under the action of different chemical additives. The hydration products, and microstructure and pore structure of the SCMs are analyzed using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and mercury intrusion porosimetry. The findings of this study demonstrate that chemical activation plays a significant role in the strength development of SCMs. Among the five chemical activators tested, Triethanolamine (TEA) had the greatest influence on mechanical properties. The maximum compressive strength of the SCMs at 28 days was 42.9 MPa at a dosage of 1%. Specifically, the addition of TEA promotes volcanic ash reactions, and the high fineness of SCM provides nucleation sites for hydration products. Interactions between the volcanic ash reaction and the complexation reaction of TEA have a positive effect on compressive strength development. This research expands the potential for IOTs SCMs through chemical activation methods for value-added applications.

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“…Slags have low activity, unstable chemical and mineral composition, and contain heavy metals with hazardous properties, posing an environmental risk. All these points limit the use of slags in the construction industry as inert aggregates and fillers [31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Deep Processing of Dump Slag from the Copper-Nickel Industry

Kasikov

Shchelokova

Timoshchik

et al. 2023

Metals

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This work proposes an environmentally safe and economically feasible method of waste copper-nickel production slag utilization (Kola Mining-Metallurgical Company, Nornickel, Kola Peninsula, Russia). This process involves the decomposition of slag by diluted solutions of sulfuric acid (7–10 wt.% H2SO4) with a transfer in a solution of more than 70% silicon, 77% iron and 78% magnesium, and a concentration of non-ferrous metals in the residue (~70%). Copper ions were used in the leaching stage to prevent the release of hydrogen sulfide into the working atmosphere. Dehydration of the solution, followed by washing of water-soluble sulphates from silica, was carried out to separate silica from the leaching solution. The dehydration temperature effect on the silica structural characteristics was determined. The possibility of recovering non-ferrous metals from solutions after silica extraction by precipitation, in the form of copper cementite, and the sum of nickel and cobalt sulfides, was evaluated. Pigment-grade iron dioxide, magnesium sulphate and aluminium hydroxide were obtained by dehydration of the solution after extraction of base metals, calcination and other operations. Sulfuric acid leaching resulted in the disclosure of sulfide grains encapsulated in ferrosilicate, which is a favorable factor for flotation. The depleted residue can be successfully used in the construction industry.

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Evaluation of the microstructure and micromechanics properties of structural mortars with addition of iron ore tailings

Cited by 4 publications

References 55 publications

Use of Dregs as a Replacement for Hydrated Lime in Cement Coating Mortar

Use of Dregs as a Replacement for Hydrated Lime in Cement Coating Mortar

The Role of Chemical Activation in Strengthening Iron Ore Tailings Supplementary Cementitious Materials

Deep Processing of Dump Slag from the Copper-Nickel Industry

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