Effect of sillimanite sand on the mechanical property and thermal resistance of alkali-activated slag mortar

Sharma, Raju; Pei, Junjie; Miah, Md Jihad; Jang, Jeong Gook

doi:10.1016/j.conbuildmat.2023.130654

Cited by 14 publications

(2 citation statements)

References 54 publications

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“…It is a polymorph of aluminosilicate [127], [128], [129]. Sillimanite sand improved the compressive and flexural strength and resistance to elevated temperatures of alkali-activated slag mortars [130]. Sillimanite enhanced the wear resistance of the composite specimens [131].…”

Section: X-ray Diffraction Analysis Of Fly Ash and Ggbsmentioning

confidence: 99%

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

Kumar Darapu,

Vindula

2023

IOP Conf. Ser.: Earth Environ. Sci.

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Alkali contamination induces swelling in the inherently non-swelling soils, resulting in heave severely damaging the sub and superstructures. Stabilization measures must be taken in vulnerable areas to prevent such colossal losses. Considerable research has been conducted regarding the swelling behavior of soils contaminated with alkalis and the impact of subsequent stabilization techniques utilizing different industrial byproducts and pozzolanic materials. However, there is a paucity of such studies on the Red Earth (RE) of the Visakhapatnam region. Furthermore, limited attention was given to the effects of extremely low concentrations of alkalis on the swelling behavior of soils. RE in the study area of the Visakhapatnam region predominantly consists of quartz, kaolinite, and hematite. In phase 1 of the experimental analysis, RE was contaminated with a highly dilute NaOH solution (0.05 N), and the resulting swell characteristics were investigated. A free swell of 10% was observed. One-dimensional standard oedometer tests revealed an equilibrium swelling of 5.6%, indicating significant potential for substantial heave and subsequent damage. X-ray diffraction (XRD) analysis revealed the formation of natrolite and analcime zeolites with a hollow structure, which caused the swell. Peaks of silicate minerals like paragonite and ussingite were also observed, indicating the dissolution of authigenic minerals and new precipitations even at lower concentrations of NaOH. In phase 2, swell tests were conducted on a mixture of contaminated red earth (50% w/w), fly ash (25% w/w), and ground granulated blast furnace slag (GGBS, 25% w/w), and it was observed that the swelling was completely arrested. XRD analysis unveiled that even though siliceous zeolites were formed, the development of chrysotile, attapulgite, tobermorite, and dicalcium silicate effectively inhibited the swelling with their pozzolanic behavior.

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Section: X-ray Diffraction Analysis Of Fly Ash and Ggbsmentioning

confidence: 99%

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

Kumar Darapu,

Vindula

2023

IOP Conf. Ser.: Earth Environ. Sci.

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“…The volumetric expansion effect can effectively offset the volumetric shrinkage of the product at high temperatures and improve the thermal shock resistance of the products. Sillimanite can be used as raw materials for refractories [7], synthetic mullite [8][9][10][11], metal composites [12], construction and building materials [13][14][15], and so on. Thus, sillimanite is widely used in metallurgy, ceramics, and other fields.…”

Section: Introductionmentioning

confidence: 99%

The Dissolution Mechanism of Low-Molecular-Weight Organic Acids on the Sillimanite

Zhang,

Yu,

Zhong

et al. 2023

Materials

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The interaction between low-molecular-weight organic acids (LMWOAs) and minerals in nature has been widely studied; however, limited research has been conducted on the dissolution mechanism of sillimanite in the presence of different organic acids. In this study, the interaction between the sillimanite sample and LMWOAs (citric acid, oxalic acid, and citric/oxalic mixture) at the same pH was investigated. The dissolution rate of Si and Al was high during the initial reaction time, then slowed down in the presence of LMWOAs. The dissolution data for Si and Al from sillimanite in the LMWOAs fit well with the first-order equation (Ct = a(1 − exp(−kt))) (R2 > 0.991). The dissolution process of sillimanite in the organic acids was controlled by the surface chemical reaction step. The dissolution concentration of Si in aqueous citric acid was higher than that in oxalic acid. In contrast, the dissolution concentration of Al in oxalic acid was more than that in citric acid. The maximum concentrations of Si and Al in the presence of composite organic acids were 1754 μmol/L and 3904 μmol/L. The sillimanite before and after treatment with LMWOAs were studied using X-ray diffraction (XRD) and scan electron microscopy (SEM). These results are explained by the characterization of the sillimanite. Under the single acid solution, the (210) crystal plane with a high areal density of Al in sillimanite was easily dissolved by the oxalic acid, while the (120) in sillimanite with a high areal density of Si was more easily dissolved by citric acid. In the composite organic acids, the Si-O bond and Al-O bond in sillimanite were attacked alternately, leading to the formation of some deeper corrosion pits on the surface of sillimanite. The results are of interest in the dissolution mechanisms of sillimanite in the low-molecular-weight organic acids and the environmentally friendly activation of sillimanite.

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Manufacturing non-sintered ceramsite from dredged sediment, steel slag, and fly ash for lightweight aggregate: production and characterization

Deng,

Li,

et al. 2024

Environ Sci Pollut Res

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Effect of sillimanite sand on the mechanical property and thermal resistance of alkali-activated slag mortar

Cited by 14 publications

References 54 publications

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

Mitigation Measures of Swelling Characteristics in Alkali-Contaminated Red Earth using Fly Ash and GGBS Blends

The Dissolution Mechanism of Low-Molecular-Weight Organic Acids on the Sillimanite

Manufacturing non-sintered ceramsite from dredged sediment, steel slag, and fly ash for lightweight aggregate: production and characterization

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