Improved mechanical strength of magnesium oxysulfate cement using ferric sulfate

Chen, Xiaoyang; Chen, Bing; Chang, Jun; Xu, Xing; Sun, Enyu; Guan, Yan; Wang, Shaoyan

doi:10.1016/j.jobe.2023.106007

Cited by 1 publication

(3 citation statements)

References 35 publications

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“…It can be seen that a 5 wt.%-30 wt.% addition of filler Q exhibited a stronger enhancement effect on the compressive strength than that on the flexural strength for MOS cement. As shown in Figure 5c, all of the hardened pastes showed volume drying shrinkage when curing in air, owing to the evaporation of free water molecules [3,12], but a 10 wt.%~20 wt.% addition of filler Q effectually decreased the drying shrinkage of the hardened MOS cement. According to the Ref.…”

Section: Early Hydration Process Of Mos Cement Containing Filler Qmentioning

confidence: 95%

“…Magnesium oxysulfate (MOS) cement, a type of the air-dried magnesia (MgO)-based cement, is formed from the reaction of reactive MgO and magnesium sulfate (MgSO 4 ) solution at ambient temperature [1][2][3]. Unlike the chemical composition of ordinary Portland cement (OPC), that of MOS cement is magnesium oxide rather than calcium oxide [2,3]. Meanwhile, compared with a magnesium oxychloride (Sorel or MOC) cement system, there is no free chloride ion in the MOS cement system.…”

Section: Introductionmentioning

confidence: 99%

“…It can be concluded that these inorganic or organic chemical additives can reduce the total pore volume of MOS matrix via promoting the growth of phase 5-1-7 crystals, enhancing the mechanical capability of MOS cement. The hardened MOS cement with chemical additives exhibits high later mechanical strength, but its setting time is increased and the early mechanical strength is decreased due to the electrostatic and steric stabilization of weak acids and their salts [3,16]. This limits the extensive utilization of MOS cement.…”

Section: Introductionmentioning

confidence: 99%

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Study of Using Quartz Powder as a Mineral Admixture to Produce Magnesium Oxysulfate Cement

Wang,

Pang,

Chen

et al. 2023

Minerals

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Magnesium oxysulfate (MOS) cement features potential advantages, including light weight, green and environmental protection, low thermal conductivity, and high frost- and fire-resistance, but its poor mechanical strength limits the extensive utilization in the architectural engineering. In this study, low-cost quartz (Q) was used as a mineral admixture to increase the mechanical strength of MOS pastes. The impact of the filler Q on the early and later mechanical strength of MOS cement was investigated, in which also had an impact on fluidity, setting times, volume stability, hydration processes, phase transformations, and microstructure. The results show that hydration of periclase to form 5Mg(OH)2·MgSO4·7H2O (phase 5-1-7) in this system was a multi-stage reaction process. 3Mg(OH)2·MgSO4·8H2O was the first sediment in this system and was converted into phase 5-1-7. The dilution and dispersion effects of the filler Q increased the early hydration rate, shortened the setting time, and increased the content and crystallite size of phase 5-1-7, increasing the early mechanical strength of MOS cement, while the volume-filling effect of the filler Q reduced the content of large pore and total pore volume, and improved the pore structure of the MOS cement, improving the later mechanical strength of MOS cement. MOS cement containing 15 wt.% of filler Q exhibited the highest early and later mechanical strength, and the lowest volume shrinkage, which is more suitable for application in architectural engineering. Based on these results, filler Q can be used as an enhancer in MOS cement, however its enhancement mechanisms are effective only when the content of filler Q is no more than 20 wt.%.

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Section: Early Hydration Process Of Mos Cement Containing Filler Qmentioning

confidence: 95%