Monitoring the ettringite formation in cement paste using low field T2-NMR

Pop, Alexandru; Badea, C.; Ardelean, I.

doi:10.1063/1.4833714

Cited by 7 publications

(4 citation statements)

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“…Proton nuclear magnetic resonance (NMR) relaxometry is a valuable technique that can be used to extract information about the pore size distribution of porous materials. The technique relies on the proportionality between the pore size and the relaxation time (transverse or longitudinal) of protons belonging to the liquid molecules confined inside pores [ 27 , 28 , 29 ]. Thus, from the relaxation time distribution, it is possible to extract the pore size distribution.…”

Section: Introductionmentioning

confidence: 99%

“…Note, however, that the proportionality between the pore size and relaxation time is valid only if one neglects the bulk relaxation rate of the confined molecules. Moreover, in the case of porous media with magnetic impurities, it is necessary to reduce diffusion effects on transverse relaxation measurements [ 26 , 27 ]. A valuable approach to reduce diffusion effects on transverse relaxation measurements is to implement the well-known Carr Purcell Meiboom Gill (CPMG) technique [ 30 ] in combination with a lowfield NMR instrument.…”

Section: Introductionmentioning

confidence: 99%

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Revealing the Influence of Microparticles on Geopolymers’ Synthesis and Porosity

et al. 2020

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Geopolymers are zeolites like structures based on hydrated aluminosilicates units of SiO4 and AlO4. These units, known as poly(sialate), poly(sialate)-siloxo or poly(sialate)-disiloxo are chemically balanced by the group I cations of K+, Li+, or Na+. Simultaneously, the chemical reaction of formation, known as geopolymerization, governs the orientation of the unit, generating mesoporous structures. Multiple methods can be used for pore structure and porosity characterization. Among them, nuclear magnetic resonance (NMR) relaxometry allows the detection of the porous structure in a completely nonperturbative manner. NMR relaxometry may be used to monitor the relaxation of protons belonging to the liquid molecules confined inside the porous structure and, thus, to get access to the pore size distribution. This monitoring can take place even during the polymerization process. The present study implements transverse relaxation measurements to monitor the influence introduced by the curing time on the residual liquid phase of geopolymers prepared with two different types of reinforcing particles. According to our results, the obtained geopolymers contain three types of pores formed by the arrangement of the OH− and Si groups (Si-OH), Si-O-Si groups, Si-O-Al groups, and Si-O rings. After 48 days, the samples cured for 8 h show a high percentage of all three types of pores, however, by increasing the curing time and the percentage of reinforcing particle, the percent of pores decrease, especially, the gel pores.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revealing the Influence of Microparticles on Geopolymers’ Synthesis and Porosity

et al. 2020

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“…One can observe two distinct relaxation components in the early hydration stages that merge in a broader distribution after the acceleration stage of hydration (6 h in the case of the sample in Figure 1). The main component at the beginning of hydration, arising at long relaxation times and with a larger area, slowly shifts towards shorter values as water from the capillary pores becomes chemically bound in C-S-H and physically confined between C-S-H layers, as demonstrated by the decrease in the peak area [28,31]. It is possible to extract the T 2 values of the peak maximum, as there are no significant differences between the peak widths for these samples (see Figure 1).…”

Section: Resultsmentioning

confidence: 99%

The Effect of Silica Fume and Organosilane Addition on the Porosity of Cement Paste

et al. 2020

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The present work systematically investigates the influence of silica fume and organosilane addition on the hydration dynamics and the capillary pore formation of a cement paste. The cement samples were prepared with two water-to-cement ratios with increasing amounts of silica fume and of (3-Aminopropyl)triethoxysilane (APTES) organosilane. Low-field 1H nuclear magnetic resonance (NMR) relaxation measurements were performed during the hydration of the samples and after hydration, in order to reveal the dynamics of water molecules and the pore distribution. Increasing concentrations of silica fume impact the perceived hydration dynamics through the addition of magnetic impurities to the pore solution. However, there is a systematic change in the capillary pore size distribution with an increase in silica fume concentration. The results also show that the addition of APTES majorly affects the hydration dynamics, by prolonging the dormancy and hardening stages. While it does not influence the pore size distribution of capillary pores, it prevents cyclohexane from saturating the capillary pores.

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“…Ettringite was detected in cement-stabilized soils, as it is a mineral typically contained in cement (Chen and Jiang 2009;Nobst and Stark 2003;Pop et al 2013). The limestone or calcite often used as filler in (Komatsu et al 2009).…”

Section: High (H) So 4 2-series Stabilized With Cementmentioning

confidence: 97%

Assessment of Sulfate Concentrations in Water Used During Chemical Stabilization and Its Potential Impact on Sulfate Induced Heave

et al. 2015

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The occurrence of sulfate-induced heave of roadways that were chemically stabilized with either lime or cement can require expensive road repairs. Previous research attributed the heave to the formation of an expansive mineral named ettringite. However, not all chemically stabilized soils will exhibit heave. The overall goal of this research was to determine if the sulfate concentration in water can contribute to, or even cause, sulfate induced heave. Two soils, one with a soluble sulfate level below 3000 mg/kg and one with [8000 mg/kg sulfate, were stabilized with either lime or cement and subjected to a capillary soak with distilled water or saturated sulfate water. The low sulfate soils did not swell above the accepted limit of 1.5 %. The high sulfate soils swelled significantly (p \ 0.05) above accepted level regardless of the stabilizer used. Overall, stabilized soils subjected to a capillary soak with saturated sulfate water swelled more than soils soaked with distilled water. The results found in this study demonstrated that cement will increase the axial load capacity of the soil, but the soil will still have the potential to heave excessively if sulfate and aluminum are present above the stoichiometric requirements to from ettringite.

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Monitoring the ettringite formation in cement paste using low field T2-NMR

Cited by 7 publications

References 0 publications

Revealing the Influence of Microparticles on Geopolymers’ Synthesis and Porosity

Revealing the Influence of Microparticles on Geopolymers’ Synthesis and Porosity

The Effect of Silica Fume and Organosilane Addition on the Porosity of Cement Paste

Assessment of Sulfate Concentrations in Water Used During Chemical Stabilization and Its Potential Impact on Sulfate Induced Heave

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