The mechanical properties of magnesium oxysulfate cement enhanced with 517 phase magnesium oxysulfate whiskers

Guo, Tao; Wang, Hefang; Yang, Heng; Cai, Xiaojun; Qian, Ma; Yang, Shihao

doi:10.1016/j.conbuildmat.2017.06.024

Cited by 89 publications

(12 citation statements)

References 12 publications

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“…In recent years, to improve the mechanical performance and water resistance properties of MOSC, many researchers directed their attention to incorporating various chemical additives into the system. These additives include citric acid and citrate [8], tartaric acid [9], sodium malate [10], and phosphoric acid and phosphate [11]. The addition of additives into the MOSC induces the formation of a stronger phase (517).…”

Section: Introductionmentioning

confidence: 99%

Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement

Liu

et al. 2022

Materials

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To improve the mechanical performance and lower the production cost of magnesium oxysulfate cement (MOSC), this article investigates the effects of single and compounded addition of metakaolin (MK) and/or fly ash (FA) on the setting time, mechanical strength, water resistance, hydration product, composition, and microstructure of the resulting cement. MOSC samples with different proportions, ranging from 0 to 30 wt.%, of FA and/or MK substituting magnesium oxide (MgO) were prepared. The microstructure was explored by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. The findings suggest that adding FA can delay the setting of MOSC; however, the effect of adding MK to MOSC was reversed. Furthermore, the phase composition of the MOSC hydration products was unaltered upon adding FA and/or MK, but thicker and longer 517 phase crystals were observed. FA and MK can effectively fill the large pores of MOSC through filling and nucleation effects, reduce the pore size, and form a denser microstructure, thereby improving its mechanical properties. The optimal MOSC sample was found by substituting 10 wt.% of both FA and MK, resulting in a cement that exhibited a short setting time and an incredibly high mechanical strength and density. These findings will further the development of stronger, more cost-efficient, and more water-resistant MOSC products.

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Section: Introductionmentioning

confidence: 99%

Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement

Liu

et al. 2022

Materials

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“…Wu et al (2016) pointed out that 5Mg(OH) 2 •MgSO 4 •7H 2 O (5•1•7 phase) was formed by adding other substances such as phosphoric acid and citric acid as additives to magnesium oxysulfide cement and then undergoing various complex reactions. The 5•1•7 phase is the main strength phase of BMSC (Guo et al 2017). This type of cement has a wide range of uses in the field of civil engineering, mainly for the production of various composite panels and lightweight insulation products (Wu et al 2016;Zeng et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Influence of Magnesium Oxide Activity on Water Resistance of Basic Magnesium Sulfate Cement

Zhang

2022

ACT

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Basic magnesium sulfate cement (BMSC) is a new type of gas-hardening magnesium cementitious material. In this study, basic magnesium carbonate was used as the raw material to obtain different active magnesium oxides by calcination at different temperatures to prepare BMSC with MgO:MgSO 4 :H 2 O = 5:1:20. The effect of different active magnesium oxides and different mineral admixtures and their content on the compressive strength of BMSC before and after soaking was analyzed, and the influence of MgO activity on the water resistance of BMSC was explored. The experimental results show that the activity of MgO has a significant impact on the water resistance of BMSC, and the water resistance of BMSC prepared from low-activity MgO is better, mainly because the hydration products of BMSC prepared by low-activity MgO are 5•1•7 phases. The MgSO 4 in the 5•1•7 phase is insoluble in water; consequently, the free MgSO 4 in BMSC is scarce; thus, the phase remains unchanged. After selecting low-activity MgO (T1000) and adding mineral admixtures to study its water resistance, it was found that the BMSC softening coefficient increases with an increase in the mineral admixture content. Both fly ash and silica fume were found to improve the water resistance of BMSC and increase its water resistance.

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“…In recent years, magnesite, waste sulfuric acid and industrial waste (fly ash, slag and byproduct of magnesia) were adopted as main raw materials and through chemical additive technology [5] in the author’s research group, a new type of MgO-MgSO 4 -H 2 O cementitious material (Basic magnesium sulfate cement, BMSC) was developed. Basic magnesium sulfate whisker was the main hydration product of BMSC, whose the mechanical properties were greatly improved compared to Portland cement [6] , [7] . The chemical composition and this new whisker were analyzed to be 5 Mg (OH) 2 ·MgSO 4 7H 2 O (referred to as 5-1-7 phase) [8] .…”

Section: Introductionmentioning

confidence: 99%

Properties and microstructure of basic magnesium sulfate cement: Influence of silica fume

Tan

Sun

et al. 2021

Construction and Building Materials

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The mechanical properties of magnesium oxysulfate cement enhanced with 517 phase magnesium oxysulfate whiskers

Cited by 89 publications

References 12 publications

Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement

Effect of Fly Ash and Metakaolin on Properties and Microstructure of Magnesium Oxysulfate Cement

Influence of Magnesium Oxide Activity on Water Resistance of Basic Magnesium Sulfate Cement

Properties and microstructure of basic magnesium sulfate cement: Influence of silica fume

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