IR Spectroscopy

Ghosh, Sandip

doi:10.1016/b978-081551437-4.50008-4

Cited by 14 publications

(6 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The expansive nature of the gel is associated to water adsorbed in its structure, which can be detected from the IR‐spectrum from the peak at 1660 cm −1 and from the band in the region between 2200 to 3600 cm −1 22,25 . The 1470 cm −1 peak present in the pure gel, even though small, shows the presence of carbonates in the gel, probably associated to trona, which was detected by XRD and NMR.…”

Section: Resultsmentioning

confidence: 95%

“…3. Reference data given by several studies were used in the interpretation of infrared spectra 18–27 . The following bands appeared in both samples: bands between 2300 and 3600 cm −1 associated to the stretching vibration of X–OH (X=Si, H); bands between 457 and 600 cm −1 associated to the O–Si–O bending; between 1642 and 1660 cm −1 associated to the water bending vibration.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Lithium Nitrate on the Alkali‐Silica Reaction Gel

Schneider

Hasparyk

Silva

et al. 2008

Journal of the American Ceramic Society

View full text Add to dashboard Cite

Lithium nitrate has been used to prevent and to mediate the expansion caused by alkali‐silica reaction (ASR). However, there is limited information on how it affects the existing reaction products caused by ASR. The aim of the present work is to determine the modifications caused by the LiNO3 treatment on the structure of the gel produced by ASR. ASR gel samples obtained from a concrete dam were exposed to an aqueous solution of lithium nitrate and sodium hydroxide with molar LiNO3/ NaOH=0.74, and the resulting products were analyzed by X‐ray diffraction, infrared spectroscopy, and solid‐state nuclear magnetic resonance of 29Si, 23Na, and 7Li. The treatment of the gel samples produces significant structural modifications in ASR products. A new amorphous silicate compound incorporating Li+ ions is formed, with an average silicate network that can be described as linear in contrast with the layered structure of the original gel. This elimination of the layered structure after the Li‐based treatments may be related to the reduction of the tendency of the gel to expand. Also, several crystalline compounds containing potassium indicate the release of this species from the original ASR gel.

show abstract

Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Effect of Lithium Nitrate on the Alkali‐Silica Reaction Gel

Schneider

Hasparyk

Silva

et al. 2008

Journal of the American Ceramic Society

View full text Add to dashboard Cite

show abstract

“…FTIR spectra have been extensively used to distinguish crystalline calcium carbonate polymorphs (calcite, aragonite and vaterite) (Ghosh ). FTIR spectra (Fig.…”

Section: Resultsmentioning

confidence: 99%

AlkaliphilicBacillusspecies show potential application in concrete crack repair by virtue of rapid spore production and germination then extracellular calcite formation

et al. 2017

View full text Add to dashboard Cite

Aims: Characterization of alkaliphilic Bacillus species for spore production and germination and calcite formation as a prelude to investigate their potential in microcrack remediation in concrete. Methods and Results: Conditions, extent and timing of endospore production was determined by dark-field light microscopy; germination induction and kinetics were assessed by combining reduction in optical density with formation of refractile bodies by phase-contrast microscopy. Bacillus pseudofirmus was selected from several species as the most suitable isolate. Levels and timing of calcium carbonate precipitated in vitro by B. pseudofirmus were evaluated by atomic absorption spectroscopy and structural identity confirmed as calcite and aragonite by Raman spectroscopy and FTIR. The isolate produced copious spores that germinated rapidly in the presence of germinants L-alanine, inosine and NaCl. Bacterial cells produced CaCO 3 crystals in microcracks and the resulting occlusion markedly restricted water ingress. Conclusions: By virtue of rapid spore production and germination, calcium carbonate formation in vitro and in situ, leading to sealing of microcracks, B. pseudofirmus shows clear potential for remediation of concrete on a commercial scale. Significance and Impact of the Study: Microbial sealing of microcracks should become a practicable and sustainable means of increasing concrete durability.

show abstract

“…[107][108][109][110][111] The band centered around 1640 cm -1 is assigned to the bending of molecular H2O in the gel, while the broad band extending from 2200 to 3700 cm -1 arises from the stretching of X-OH, where X = H, Na, K or Si is bonded to the OH groups in the amorphous silica matrix. [112,113] Moreover, Figure 25c displays a representative thermal decomposition profile of the synthesized gels, showing significant mass loss below 200°C which is typical of cementitious gel phases containing evaporable water, e.g., calcium silicate hydrate, C-S-H, [114] and sodium aluminum silicate hydrate N-A-S-H gels. [76]…”

Section: Estimation Of Thermodynamic Propertiesmentioning

confidence: 99%

The Influences of Neutron Irradiation on Aggregate Induced Degradation of Concrete

Sant

2018

View full text Add to dashboard Cite

December 10, 2018 Characterization of mineral aggregatesNatural rocks may contain traces of other phases distinct from their main mineralogical components. Macroscopic observations of natural samples of albite, anorthite, almandine and dolomite suggest that they are impure. To characterize the purity of the samples, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), x-ray diffraction (XRD), and Raman spectroscopy were employed, as described below. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS)Energy dispersive X-ray spectroscopy (EDS) is an analytical technique that can be coupled with scanning electron microscopy (SEM). SEM-EDS can be used for elemental analysis and chemical characterization of different areas on a sample surface, with a resolution that is on the order of a few microns.[4] The working principle of EDS relies on the interaction between X-rays and the atoms on the sample surface. To stimulate characteristic X-rays from a specimen, highenergy electrons are focused on the sample, and the incident beam excites electrons in the inner shell of an atom, creating an electron hole that is then filled by electrons in the outer shell, releasing energy in the process. The amounts and energies of X-rays emitted from the sample are measured by a spectrometer to create a unique emission spectrum depending on the atomic structure.[5] Prior to SEM measurements, selected mineral samples were powdered to few micrometers in size using a ball mill, and then coated with Au for 1 minute using a Hummer® 6.6 Sputter Coater, producing a film with thickness of about 6-7 nanometers. SEM imaging was carried out using secondary electrons and backscattered electrons using a FEI Nova NanoSEM 230 (7 kV, 80 pA). X-ray Diffraction (XRD)Selected samples were analyzed using powder X-ray diffraction (XRD) to identify the crystalline phases that are present.[6] The pristine mineral samples were ball milled to produce particles that are a few micrometers in size. XRD patterns were recorded using a Bruker D8-Advance powder X-ray diffractometer in θ-θ Bragg-Brentano geometry, using Cu Kα radiation (λ = 1.5406 Å), 40 kV accelerating voltage, and 40 mA beam intensity. A 2θ range of 10° to 70°, a 2θ scan step size of 0.02°, and an exposure time of 0.5 seconds per step were employed. The peak locations and relative peak intensities in the X-ray diffractograms provide information on the particular crystalline compounds that are present in the sample. Raman SpectroscopyRaman spectroscopy is a technique for measuring the vibrational and rotational molecular bonding in a system. [7] Therefore, Raman spectroscopy was applied to observe structural changes in the mineral samples after ion-implantation. Similar to SEM-EDS and XRD, Raman spectroscopy also provides a fingerprint spectrum for the species present in a sample.[8] The working principle for Raman analysis relies on both elastic (Rayleigh) and inelastic (Raman) scattering of a laser beam. A monochromatic laser of wavelength near th...

show abstract

IR Spectroscopy

Cited by 14 publications

References 31 publications

Effect of Lithium Nitrate on the Alkali‐Silica Reaction Gel

Effect of Lithium Nitrate on the Alkali‐Silica Reaction Gel

AlkaliphilicBacillusspecies show potential application in concrete crack repair by virtue of rapid spore production and germination then extracellular calcite formation

The Influences of Neutron Irradiation on Aggregate Induced Degradation of Concrete

Contact Info

Product

Resources

About