Effects of fly ash, phosphoric acid, and nano-silica on the properties of magnesium oxychloride cement

Huang, Qing; Zheng, Weixin; Xiao, Xueying; Dong, Jinmei; Wen, Jing; Chang, Chenggong

doi:10.1016/j.ceramint.2021.08.347

Cited by 26 publications

(13 citation statements)

References 36 publications

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“…As an inert additive, a little chemical reaction occurred when FA was added into MOC pastes and the presence of FA prevented the generation of hydration products to some extent [ 32 ]. Similar results were obtained by Huang et al, showing the replacement of MgO by FA in MOC will lead to a large strength reduction due to the decreased amount of main hydrate [ 10 ]. Moreover, the lubricating effect induced by spherical FA particles would reduce the mechanical interaction with the hydrates, resulting in a negative effect on the strength of hardened pastes [ 33 ].…”

Section: Role Of Fly Ash In Moc Pastessupporting

confidence: 85%

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Eco-Sustainable Magnesium Oxychloride Cement Pastes Containing Waste Ammonia Soda Residue and Fly Ash

et al. 2022

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Magnesium oxychloride cement (MOC), a type of special construction material, has drawn much research attention in solid waste utilization and environmental protection due to its eco-friendly production. Ammonia soda residue (ASR), a by-product generated from sodium carbonate manufacturing, is one of the industrial wastes that can be recycled in MOC systems. However, ASR exhibits adverse effects on the fresh performance and volume stability of MOC pastes. This paper aims at improving the properties of ASR-MOC by introducing fly ash (FA), solid waste from the power industry. Firstly, the roles of FA in MOC pastes are evaluated and analyzed. Then, three substitution ratios of FA (33.3%, 50% and 66.7% in weight) for ASR are designed for MOC pastes with 10% to 40% industrial wastes. Flowability, setting, strength and expansion of all mixtures were experimentally studied. Furthermore, X-ray diffraction (XRD) and scanning electron microscope (SEM) approaches were adopted to illustrate the microstructure changes. Results show that by adding different amounts of FA, the inferior flowability of MOC caused by ASR can be improved by 6–23%, the setting process can be prolonged by 30–55% and the expansion ratio can be reduced by 14–66%. The intensity of characteristic peaks of 5-phase and Mg(OH)2, together with the degrees of crystallization in XRD curves, well explain the strength variation and volume stability of ASR-MOC pastes. According to the regulation of relative specification, up to 20% of solid wastes in weight (10% FA + 10% ASR) can be consumed, contributing greatly to the greener sustainable development of construction materials.

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Section: Role Of Fly Ash In Moc Pastessupporting

confidence: 85%

“…MOC, produced from magnesium oxide and magnesium chloride mainly, is commonly used in various building materials, such as fire-resistant panels, tiles, decorative components, ventilation pipes, etc. [ 9 , 10 ]. Compared with traditional cement, MOC has the advantages of ultra-high strength, wear and fire resistance.…”

Section: Introductionmentioning

confidence: 99%

Eco-Sustainable Magnesium Oxychloride Cement Pastes Containing Waste Ammonia Soda Residue and Fly Ash

et al. 2022

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“…Second, 12 groups of MOCLC were prepared according to the division criteria in Section 2.1. Accordingly, an average of three specimens was prepared for [23,25]. Te water resistance coefcient is defned as the ratio of the immersed compressive (splitting) strength to the dry compressive (splitting) strength of the specimen and is calculated using the following formula:…”

Section: Te Strength Of Moclcmentioning

confidence: 99%

“…Zheng et al investigated the mechanical characteristics of magnesium oxychloride cement concrete (MOCC) using the changing law of the microstructure. Te addition of MOC increases the pavement strength of the structure, which was based on X-ray difraction (XRD) and scanning electron microscopy (SEM) results, as well as the compressive and fexural strengths of MOCC at various ages [23]. Cheng et al investigated the long-term mechanical properties of MOCC, measured the change in the phase 5 content in MOCC by XRD and SEM, and tested the compressive strength of MOCC at 28, 180, and 270 days.…”

Section: Introductionmentioning

confidence: 99%

“…Although the addition of MOC to concrete buildings can signifcantly increase their mechanical and durability features, water resistance issues still exist [27,28]. Phases 5 and 3 are easy to decompose in the water environment, and the strength of MOC decreases gradually [23]. Te specifc decomposition formula is shown in equations ( 2) and (3).…”

Section: Introductionmentioning

confidence: 99%

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Influence of Mineral Admixtures on the Properties of Magnesium Oxychloride Cement Lean Concrete

Guan

et al. 2023

Advances in Materials Science and Engineering

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This study investigated the effects of light-burned magnesia, fly ash (FA), dolomite powder (DP), and limestone powder (LP) contents on the performance of magnesium oxychloride cement lean concrete (MOCLC). The effects of light-burned magnesia and mineral admixture content on the mechanical properties and durability of MOCLC were tested by the compressive strength test, splitting strength test, water resistance test, shrinkage test, and fatigue test, respectively. The results revealed that the optimum dosage of MgO was 4%. The optimum dosages of FA, DP, and LP were 25%, 20%, and 20% of the cement dosage, respectively. The compressive and splitting strengths of the MOCLC were decreased by the addition of FA and DP. Due to part of the internal pores of MOCLC were filled with FA and DP, the decomposition of the main strength phase 5Mg (OH)2·MgCl2·8H2O (phase 5) was suppressed and the water resistance of MOCLC was improved. The addition of FA and DP also improved the shrinkage resistance, and the fatigue resistance of MOCLC was also improved by the addition of FA and DP. The water resistance, shrinkage, and fatigue properties of MOCLC with a FA content of 25% were better than those of MOCLC with DP and LP.

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Carbon sequestration behavior of magnesium oxychloride cement based on salt lakes magnesium residue and industrial solid waste

Li,

Zheng

et al. 2024

Carbon Capture Science & Technology

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Effects of fly ash, phosphoric acid, and nano-silica on the properties of magnesium oxychloride cement

Cited by 26 publications

References 36 publications

Eco-Sustainable Magnesium Oxychloride Cement Pastes Containing Waste Ammonia Soda Residue and Fly Ash

Eco-Sustainable Magnesium Oxychloride Cement Pastes Containing Waste Ammonia Soda Residue and Fly Ash

Influence of Mineral Admixtures on the Properties of Magnesium Oxychloride Cement Lean Concrete

Carbon sequestration behavior of magnesium oxychloride cement based on salt lakes magnesium residue and industrial solid waste

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