Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aluminate by 27Al and 29Si MAS NMR spectroscopy

Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Joergen

doi:10.1016/j.cemconres.2003.10.009

Cited by 316 publications

(179 citation statements)

References 24 publications

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“…The development of a signal at 10 ppm with an unresolved downfield shoulder at ~14 ppm, are respectively indicative of the formation of monosulphate and ettringite. As hydration proceeds, the ettringite and monosulphate signals become better resolved and an upfield shoulder appears at ~4 ppm which is attributed to the presence of a third poorly crystalline calcium aluminate hydrate phase or aluminium hydroxide gel 12,17) . The upfield shift of the tetrahedral aluminium signal to 66.5 ppm during the first week of hydration is attributed to the progressive incorporation of aluminium into the silicate chain structure of the C-S-H gel phase 12) .…”

Section: Deconvolution and Analysis Ofmentioning

confidence: 99%

“…29 Si MAS NMR spectroscopy 29 Si MAS NMR spectroscopy can be used to determine the co-ordination environment and the extent of polymerization of silicate species in mineral phases 14) . Isolated Q 0 silicate species have a chemical shift range of −65 to −75 ppm, Q 1 species resonate between −78 and −82.5 ppm, and Q 2 silicates give rise to signals in the range −84 to −87.5 ppm 11,12,15) . Replacement of silicon for aluminium in a neighbouring tetrahedron increases the chemical shift by approximately 5 ppm per Al substitution.…”

Section: Powder Xrd Analysismentioning

confidence: 99%

“…(It should be noted that the sharp signal from belite at −72 ppm persists in the subtracted spectrum, as the hydration of belite is considerably slower than that of alite.). The relative abundance of the various Q n species and degree of hydration were then calculated from the subtracted and deconvoluted spectra 12) .…”

Section: Si and 27mentioning

confidence: 99%

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The hydration chemistry of ProRoot MTA

Coleman

2015

Dent. Mater. J.

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'Tooth-coloured' ProRoot MTA is an endodontic cement comprising an 80:20 wt% mixture of white Portland cement (WPC) and bismuth oxide. The setting reactions within this cement system are not currently well understood. Accordingly, this research monitors the early hydration chemistry of ProRoot MTA by X-ray diffraction, solid state nuclear magnetic resonance and Fourier transform infrared spectroscopies, and isothermal calorimetry. The initial rate of hydration is rapid with 40% having reacted within the first 24 h; it then slows considerably such that within 3 days the hydration reactions are 58% complete and only increase by a further 1% within one week. The relatively fast reaction of alite to form C-S-H gel and portlandite, and the development of the calcium aluminosulphate phases, are as would be anticipated for the hydration of pure WPC. These findings confirm that bismuth oxide is an inert additive which does not participate in the hydration reactions.

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Section: Deconvolution and Analysis Ofmentioning

confidence: 99%

Section: Powder Xrd Analysismentioning

confidence: 99%

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The hydration chemistry of ProRoot MTA

Coleman

2015

Dent. Mater. J.

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“…From the deconvolution results, the degree of reaction (DR) of GGBFS, the average chain length (mean chain length-MCL) and the Si/Al-ratio of the C-(A)-S-H phases are calculated [35,38,42,43]. The formulas are quoted elsewhere [38].…”

Section: Nuclear Magnetic Resonance Spectroscopymentioning

confidence: 99%

Effect of slag chemistry on the hydration of alkali-activated blast-furnace slag

2014

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This paper presents results of detailed investigations about the alkaline activation of ground granulated blast furnace slags whose chemical composition were modified. Sodium hydroxide and potassium silicates were used as alkaline activators. The influence of the CaO/SiO 2 ratio, the Al 2 O 3 and TiO 2 content of the slag composition on the hydration reaction was analyzed utilizing isothermal heat flow calorimetry, compressive strength development of binder samples, 29 Si MAS NMR spectroscopy and molybdate method. It could be shown that the TiO 2 content of the slag has only minor influence on the hydraulic reactivity and compressive strength of the alkaline activated binders.The variation of the Al 2 O 3 content of the slag leads to different results. A rise in Al 2 O 3 content enhanced the strength if activating with NaOH but resulted in a lower strength if activating with potassium silicate. The results of the 29 Si MAS NMR spectroscopy verify the decrease in the reaction degree with increase of Al 2 O 3 content. This is associated with the rise of the chain length of the C-(A)-S-H phases by incorporation of Al-O tetrahedrons resulting in a lower Si/Al-ratio. A decrease in the C/S-ratio yielded to a lower heat evolution, whereas the reaction was delayed if activated with potassium silicate with higher silicate content. The increase of the C/S-ratio caused in less condensed slag glass and therefore an enhancement of the reaction degree with a simultaneous decrease of silicate chain length, as seen by 29 Si NMR. These outcomes fit well with the results measured by the molybdate method.

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“…Chemical shifts are given in ppm relative to AlCl 3 ·6H 2 O. The assignment of the signals is accomplished in accordance with the published data [9][10][11]. The deconvolution of spectra was realised by using software Dmfit.…”

Section: Experimental Partmentioning

confidence: 99%

The Impact of Aluminum-Containing Set Accelerators on Sulfate Resistance of Portland Cement Compositions

Brykov¹,

Vasiliev²,

Мокеев³

2013

MSA

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This study contains comparative research of sulfate resistance of ordinary Portland cement pastes with addition of basic aluminum sulfate (hydroxosulfate, Al(OH) 1.78 (SO 4 ) 0.61 ) and amorphous Al(OH) 3 . Over 3 months of storing in sodium sulfate solution, the most significant expansion and deterioration occur in case of samples with aluminum hydroxide. During sulfate resistance test, the ratio between aluminum nuclei in AFt (ettringite) and AFm phases was studied by 27 Al-MAS NMR, and the impact of aluminum-containing admixtures on this ratio was specified. In accordance with NMR data, in samples with Al(OH) 3 , the rate of secondary ettringite formation becomes noticeable after one month of storing in sulfate solution. For samples with Al(OH) 1.78 (SO 4 ) 0.61 , the rate of elongation and temper of changes in molar ratio between sulfoaluminate phases were comparable with reference samples without admixtures.

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Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aluminate by 27Al and 29Si MAS NMR spectroscopy

Cited by 316 publications

References 24 publications

The hydration chemistry of ProRoot MTA

The hydration chemistry of ProRoot MTA

Effect of slag chemistry on the hydration of alkali-activated blast-furnace slag

The Impact of Aluminum-Containing Set Accelerators on Sulfate Resistance of Portland Cement Compositions

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