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Hydration mechanism of a sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) in supersulfated cement system
https://orcid.org/0000-0002-1550-9067
Abstract A sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) was synthesized via hydrothermal method within an hour under atmospheric pressure and the influence of omongwaite on the hydration mechanism of supersulfated cement (SSC) was studied. Isothermal calorimetry, X-ray diffraction (XRD), and field emission scanning electron microscopy (SEM) was used to investigate hydration process and early hydration products in hour scale. Quantitative X-ray diffraction (QXRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) were applied to examine the hydration products in 28 days. The results indicated that in the early stage of hydration, the hemihydrate whisker was hydrated and converted into columnar shape dihydrate gypsum, resulted in initial setting of SSC paste in ∼1 h, which is favorable for SSC. The columnar shape dihydrate gypsum may because of presence of sodium and high concentration of ions. Along with Al3+ ions that release from slag, needle-like ettringite was formed and interlocked with columnar shape dihydrate gypsum to form a framework. This gives SSC paste 1-day compressive strength ∼10 MPa. As hydration proceeds, gypsum is gradually consumed and ettringite continue to form, ensuring further development of strength in later stage. Columnar gypsum that originates from omongwaite acts as both a hydration product and a reactant, exhibiting good coordination in the strength development of SSC paste.
Highlights Sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) can be synthesized within 1 h under ambient pressure. Omongwaite shortened the setting time of SSC. Omongwaite improved the early compressive strength of SSC. Gypsum that originate from omongwaite, act as both a hydration product and a reactant in SSC, leading to rapid hydration and development of strength.
Hydration mechanism of a sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) in supersulfated cement system
https://orcid.org/0000-0002-1550-9067
Abstract A sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) was synthesized via hydrothermal method within an hour under atmospheric pressure and the influence of omongwaite on the hydration mechanism of supersulfated cement (SSC) was studied. Isothermal calorimetry, X-ray diffraction (XRD), and field emission scanning electron microscopy (SEM) was used to investigate hydration process and early hydration products in hour scale. Quantitative X-ray diffraction (QXRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) were applied to examine the hydration products in 28 days. The results indicated that in the early stage of hydration, the hemihydrate whisker was hydrated and converted into columnar shape dihydrate gypsum, resulted in initial setting of SSC paste in ∼1 h, which is favorable for SSC. The columnar shape dihydrate gypsum may because of presence of sodium and high concentration of ions. Along with Al3+ ions that release from slag, needle-like ettringite was formed and interlocked with columnar shape dihydrate gypsum to form a framework. This gives SSC paste 1-day compressive strength ∼10 MPa. As hydration proceeds, gypsum is gradually consumed and ettringite continue to form, ensuring further development of strength in later stage. Columnar gypsum that originates from omongwaite acts as both a hydration product and a reactant, exhibiting good coordination in the strength development of SSC paste.
Highlights Sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) can be synthesized within 1 h under ambient pressure. Omongwaite shortened the setting time of SSC. Omongwaite improved the early compressive strength of SSC. Gypsum that originate from omongwaite, act as both a hydration product and a reactant in SSC, leading to rapid hydration and development of strength.
Hydration mechanism of a sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) in supersulfated cement system
https://orcid.org/0000-0002-1550-9067
Abstract A sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) was synthesized via hydrothermal method within an hour under atmospheric pressure and the influence of omongwaite on the hydration mechanism of supersulfated cement (SSC) was studied. Isothermal calorimetry, X-ray diffraction (XRD), and field emission scanning electron microscopy (SEM) was used to investigate hydration process and early hydration products in hour scale. Quantitative X-ray diffraction (QXRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) were applied to examine the hydration products in 28 days. The results indicated that in the early stage of hydration, the hemihydrate whisker was hydrated and converted into columnar shape dihydrate gypsum, resulted in initial setting of SSC paste in ∼1 h, which is favorable for SSC. The columnar shape dihydrate gypsum may because of presence of sodium and high concentration of ions. Along with Al3+ ions that release from slag, needle-like ettringite was formed and interlocked with columnar shape dihydrate gypsum to form a framework. This gives SSC paste 1-day compressive strength ∼10 MPa. As hydration proceeds, gypsum is gradually consumed and ettringite continue to form, ensuring further development of strength in later stage. Columnar gypsum that originates from omongwaite acts as both a hydration product and a reactant, exhibiting good coordination in the strength development of SSC paste.
Highlights Sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) can be synthesized within 1 h under ambient pressure. Omongwaite shortened the setting time of SSC. Omongwaite improved the early compressive strength of SSC. Gypsum that originate from omongwaite, act as both a hydration product and a reactant in SSC, leading to rapid hydration and development of strength.
Hydration mechanism of a sodium-doped phosphogypsum-based hemihydrate whisker (omongwaite) in supersulfated cement system
Huang, Jiyun (author) / Huang, Jian (author) / Min, Junjie (author) / Lv, Ruoyun (author) / Kuang, Hao (author) / Hu, Hailong (author) / Yang, Rong (author) / Tang, Pei (author) / Zhao, Qinglin (author) / Jian, Shouwei (author)
2024-04-10
Article (Journal)
Electronic Resource
English