Effect of C/S ratio on morphology and structure of hydrothermally synthesized calcium silicate hydrate

He, Yongjia; Zhao, Xiaogang; Lü, Linnü; Struble, Leslie J.; Hu, Shuguang

doi:10.1007/s11595-011-0308-z

Cited by 57 publications

(23 citation statements)

References 8 publications

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“…A lower Ca/Si ratio was observed in the sample of the 65% RH condition than in that of the control. This is consistent with previous studies [50,51], which propose that the higher the polymerization degree, the lower the Ca/Si ratio. However, the hydrates under the water condition showed an unexpectedly higher Ca/Si ratio above 2.…”

Section: Discussionsupporting

confidence: 94%

Impacts of Space Restriction on the Microstructure of Calcium Silicate Hydrate

et al. 2021

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The effect of hydration space on cement hydration is essential. After a few days, space restriction affects the hydration kinetics which dominate the expansion, shrinkage and creep of cement materials. The influence of space restriction on the hydration products of tricalcium silicate was studied in this paper. The microstructure, morphology and composition of calcium silicate hydrate (C-S-H) were explored from the perspective of a specific single micropore. A combination of Raman spectra, Fourier transform infrared spectra, scanning electron microscopy and energy dispersive X-ray spectroscopy were employed. The results show that space restriction affects the structure of the hydration products. The C-S-H formed in the micropores was mainly composed of Q3 silicate tetrahedra with a high degree of polymerization. The C-S-H formed under standard conditions with a water to cement ratio of 0.5 mostly existed as Q2 units. Space restriction during hydration is conducive to the formation of C-S-H with silica tetrahedra of a high polymerization degree, while the amount of water filling the micropore plays no obvious role on the polymeric structure of C-S-H during hydration.

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Section: Discussionsupporting

confidence: 94%

Impacts of Space Restriction on the Microstructure of Calcium Silicate Hydrate

et al. 2021

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“…As discussed in various theory publications [31][32][33] and also shown experimentally in Ref. 34, this can lead to significant current increase even far away from the thermionic (Richardson) regime, where electron states with energies above the barrier become populated thermally. The change of the electron emission transient could be due to structural modifications of the tip during conditioning.…”

Section: Resultsmentioning

confidence: 71%

Fiber tip-based electron source

Casandruc

Kassier

Zia

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The authors report on the first experimental characterization of a fiber tip-based electron source, where electron emission can be triggered by both electric field and optical excitation. Our approach consists of coating the open aperture of a commercial 100 nm apex size near-field scanning optical microscopy fiber tip with a 10 nm thick tungsten (W) layer, which is back-illuminated by a 405 nm continuous-wave laser beam in the presence of an extraction electric field. Despite the very low optical transmission of the fiber due to the subwavelength aperture size, measurements show a clearly enhanced emission when photoexciting the W layer with respect to pure field emission. The emission response time is slower than the optical trigger time, suggesting that thermal effects are predominant in the studied regime. To back up this hypothesis, the authors fabricated a nanometric thermocouple probe based on a Pt/Au junction and measured the temporal response of the tip temperature. The measured switch-on time for the tip temperature is consistent with the switch-on time of the optically enhanced electron emission

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“…The broadening of the peaks evidences the gel-like nature of this phase. In the case of C-S-H sample, Tobermorite (Ca 5 (Si 6 O 16 (OH) 2 )•4(H 2 O)) is the main component 20 and the presence of sharper peaks with respect to M-S-H evidences a more ordered structure.…”

Section: Resultsmentioning

confidence: 99%