The Effect of Curing Temperature on Early Hydration of Gray Cement Via Fast Field Cycling-NMR Relaxometry

Badea, C.; Pop, Alexandru; Mattea, Carlos; Stapf, Siegfried; Ardelean, I.

doi:10.1007/s00723-014-0565-z

Cited by 18 publications

(10 citation statements)

References 19 publications

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“…Transformation of the acquired data into the T 1 domain for each frequency studied provides additional insight, as is seen in Figure . While the data for water, DMSO, cyclohexane, and n -heptane exhibit single-component T 1 distribution behavior, consistent with previous relaxation time analyses of these systems, ,,− the data for methanol and acetone clearly show two T 1 components. In both cases, this minor component was associated with a T 1 time constant approximately 1–2 orders of magnitude smaller than the main component.…”

Section: Resultssupporting

confidence: 86%

Insights into Functionality-Specific Adsorption Dynamics and Stable Reaction Intermediates Using Fast Field Cycling NMR

Ward-Williams

Korb

2018

J. Phys. Chem. C

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Fast field cycling, FFC, NMR relaxometry experiments are reported in the frequency range of 10 kHz-40 MHz to characterise the molecular dynamics of a series of protic (methanol and water) and aprotic (DMSO, acetone, cyclohexane and n-heptane) adsorbates on a γ-alumina surface of catalytic interest. By analysing the data in the T1 domain two distinct peaks were observed for both methanol and acetone. In the case of methanol the two peaks have been shown to originate from the two chemical environments of methanol, which at low field strengths differentiate the O 1 H and alkyl 1 H interactions with the surface. In contrast, the second environment of adsorbed acetone is assigned to a stable reaction intermediate formed during an aldol reaction, which strongly influences other molecular adsorption processes at the surface. Inversion of the FFC-NMR data into the T1-domain enables the combination of the ability of low field NMR to characterise relaxation modes directly associated with adsorption with T1 measurements specific to functional groups and reaction intermediates, thereby avoiding misinterpretation of molecular adsorption characteristics and giving greater insight into adsorption and catalytic behaviour than is possible from the overall relaxation dispersion profiles alone.

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Section: Resultssupporting

confidence: 86%

Insights into Functionality-Specific Adsorption Dynamics and Stable Reaction Intermediates Using Fast Field Cycling NMR

Ward-Williams

Korb

2018

J. Phys. Chem. C

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“…The NMR relaxometry techniques are completely non-invasive and allow the investigation of cement samples without special prior preparation. These have been used successfully in the recent years to extract information about the porous structure of cementbased materials and to extract information with respect to the evolution of water inside the pores during the hydration process [5,8,[35][36][37][38][39][40]. In the NMR relaxometry of cement-based materials, both the longitudinal relaxation time and the transverse relaxation time can be monitored [5,8,[35][36][37][38][39][40].…”

Section: Nmr Relaxometry Approach For Determining the Pore Size Distr...mentioning

confidence: 99%

“…These have been used successfully in the recent years to extract information about the porous structure of cementbased materials and to extract information with respect to the evolution of water inside the pores during the hydration process [5,8,[35][36][37][38][39][40]. In the NMR relaxometry of cement-based materials, both the longitudinal relaxation time and the transverse relaxation time can be monitored [5,8,[35][36][37][38][39][40]. Due to the fact that longitudinal relaxation measurements are slower and are more difficult to apply to the systems that evolve during the measurement process, it is preferable for many applications to measure the transverse relaxation time.…”

Section: Nmr Relaxometry Approach For Determining the Pore Size Distr...mentioning

confidence: 99%

“…The great advantage of the NMR techniques is that they are completely non-invasive and, in addition, they permit the study of materials without prior preparation of samples. In the present work, NMR relaxometry [5,8,[35][36][37][38][39][40][41] is used, again, to determine the residual water within the pores of the material and the effects of the freeze-thaw cycles on the porous system. Using this technique, information can be obtained about the porous structure of concrete containing a mixture of cement paste and aggregates, which is similar to the approach of Wawrze ńczyk J. and Kozak W. [12] and based on the Philleo concept.…”

Section: Introductionmentioning

confidence: 99%

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Freeze–Thaw Effect on Road Concrete Containing Blast Furnace Slag: NMR Relaxometry Investigations

et al. 2021

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The present work investigates the effect of freeze–thaw cycles on the porosity of three mixtures of road concrete containing blast furnace slag in comparison with two mixtures made with conventional materials. The main technique used in our investigations is nuclear magnetic resonance (NMR) relaxometry. This permitted the extraction of information with respect to the freeze–thaw effect on pore-size distribution, which influences both the mechanical strength and the molecular transport through the material. Moreover, by using this technique, the structure of the air voids was analyzed for the entire pore system in the cement paste and the aggregate particles. The samples under study were first dried in a vacuum oven and then saturated with water or cyclohexane where the distribution of the transverse relaxation times of the protons was recorded. The NMR relaxation measurements were performed on samples extracted from specimens maintained at 300 freeze–thaw cycles and on control samples extracted from specimens kept in water during the freeze–thaw period. Scanning Electron Microscopy (SEM) was used to analyze the microstructure of concrete samples in order to obtain information about the pore sizes and the distance between them. The results from the NMR relaxation measurements were consistent with those obtained by using standard techniques for determining the porosity and the freeze–thaw resistances. The investigations made it possible to establish the optimal composition of blast furnace slag that can be incorporated into road concrete compositions. This non-invasive technique can also complete standard techniques for assessing the porosity and the progress of internal cracks during the freeze–thaw test.

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“…Low-field nuclear magnetic resonance (NMR) relaxometry techniques are valuable instruments for monitoring the cement hydration under the influence of different additives and admixtures [ 6 , 7 , 8 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. They are completely noninvasive, do not require any special sample preparation and can be applied even during the hydration process.…”

Section: Introductionmentioning

confidence: 99%

The Effect of an Accelerator on Cement Paste Capillary Pores: NMR Relaxometry Investigations

Ardelean

2021

Molecules

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Nuclear Magnetic Resonance (NMR) relaxometry is a valuable tool for investigating cement-based materials. It allows monitoring of pore evolution and water consumption even during the hydration process. The approach relies on the proportionality between the relaxation time and the pore size. Note, however, that this approach inherently assumes that the pores are saturated with water during the hydration process. In the present work, this assumption is eliminated, and the pore evolution is discussed on a more general basis. The new approach is implemented here to extract information on surface evolution of capillary pores in a simple cement paste and a cement paste containing calcium nitrate as accelerator. The experiments revealed an increase of the pore surface even during the dormant stage for both samples with a faster evolution in the presence of the accelerator. Moreover, water consumption arises from the beginning of the hydration process for the sample containing the accelerator while no water is consumed during dormant stage in the case of simple cement paste. It was also observed that the pore volume fractal dimension is higher in the case of cement paste containing the accelerator.

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The Effect of Curing Temperature on Early Hydration of Gray Cement Via Fast Field Cycling-NMR Relaxometry

Cited by 18 publications

References 19 publications

Insights into Functionality-Specific Adsorption Dynamics and Stable Reaction Intermediates Using Fast Field Cycling NMR

Insights into Functionality-Specific Adsorption Dynamics and Stable Reaction Intermediates Using Fast Field Cycling NMR

Freeze–Thaw Effect on Road Concrete Containing Blast Furnace Slag: NMR Relaxometry Investigations

The Effect of an Accelerator on Cement Paste Capillary Pores: NMR Relaxometry Investigations

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