Study of aggregate samples with iron sulfides through micro X-ray fluorescence (μXRF) and X-ray photoelectron spectroscopy (XPS)

Chinchón-Payá, Servando; Aguado, Antonio; Coloma, Fernando; Chinchón, Servando

doi:10.1617/s11527-013-0233-z

Cited by 13 publications

(5 citation statements)

References 19 publications

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“…The fact that this is observed for a degassing treatment at room temperature confirms that sulfur is not present as a dopant in the hexagonal lattice, which would confer it far higher stability. [44,45] After these observations we can confidently assignation contributions of the S2p peak to organic molecules adsorbed as surface impurities (169 eV) and in the catalyst (162-164 eV), associated to Fe as pyrite (FeS2) or pyhrrotite (FeS), [46,47] respectively . We thus find that in the synthesis of fibers with CNTs with more layers and larger diameter, the ratio of catalyst/surface S decreases rapidly from 0.7 to 0.1 (Figure 7).…”

Section: Sulfur Identificationmentioning

confidence: 96%

Surface Chemistry Analysis of Carbon Nanotube Fibers by X‐Ray Photoelectron Spectroscopy

Alemán

Vila

Vilatela

2018

Physica Status Solidi (a)

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Carbon nanotube (CNT) fibers are materials with an exceptional combination of properties, including higher toughness than carbon fibers, electrical conductivity above metals, large specific surface area (250 m2 g−1), and high electrochemical stability. As such, they are a key component in various multifunctional structures combining augmented mechanical properties with efficient interfacial energy storage/transfer processes. This work presents a thorough XPS study of CNT fibers subjected to different purification and chemical treatments, including spatially‐resolved micro XPS synchrotron measurements. The dominant feature is an inherently high degree of sp2 conjugation, leading to a strong plasmonic band and a semi‐metallic valence band lineshape. This high degree of CNT perfection in terms of longitudinal “graphitization” helps to explain reported bulk properties including the high electrical and thermal conductivity, and accessible quantum capacitance. There is also presence of organic impurities, mostly heavy carbonaceous molecules formed as by‐products during fiber synthesis and which are adsorbed on the CNTs. Sulfur, a promoter used in the CNT growth reaction, is found both in these surface impurities and associated with the Fe catalyst. The observation of strongly‐adsorbed surface impurities is consistent with the high ductility of CNT fibers, attributed to interfacial lubricity.

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Section: Sulfur Identificationmentioning

confidence: 96%

Surface Chemistry Analysis of Carbon Nanotube Fibers by X‐Ray Photoelectron Spectroscopy

Alemán

Vila

Vilatela

2018

Physica Status Solidi (a)

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“…The most frequent cause is the alkali-aggregate reaction (AAR) (Stanton 1942;Hobbs 1988;Mehta and Monteiro 2006). Hence, the majority of reported dams with expansive reactions found in the literature are related with AAR (Shayan 1988, Regamey and Hammerschlag 1995, Ulm et al 2000, Saouma et al 2007, even though several cases were reported on internal sulfate attack (ISA) (Chinchón et al 1995, Ayora et al 1998, Oliveira et al 2013a, Oliveira et al 2013b, Oliveira et al 2014, Ikumi et al 2014, Chinchón-Payá et al 2015 and alkali-carbonate reaction (ACR) (Neville 2004, Blanco et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Structural Diagnosis of a Concrete Dam with Cracking and High Nonrecoverable Displacements

Campos

López

Blanco

et al. 2016

J. Perform. Constr. Facil.

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Expansions in concrete dams may be caused by chemical or physical sources; however in certain occasions the evidences observed in the dam may not be attributed to a single cause. Mequinenza is an example of a concrete dam affected by expansions and high non-recoverable displacements that cannot be explained by the most frequent pathologies. This paper presents new hypotheses that could justify such behavior by assuming the superposition of a global phenomenon of water induced expansion in concrete in the entire dam and a localized effect consisting in the opening of cracks in the construction joints located in one of the blocks. This is validated by conducting numerical analyses through 2D finite element models that consider the nonlinear behavior of the construction joints and use zero-thickness interface elements to simulate the potential cracking planes in the dam. The results confirmed the diagnosis proposed and the capability of the model to reproduce the behavior of the dam, revealing the significant contribution of the opening of the cracks to the non-recoverable displacements in the dam.

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“…Micro-XRF is a method for mapping the elemental analysis of samples. This technique characterizes and quantifies the iron sulfides present in the aggregates without differentiating between pyrite and pyrrhotite minerals [54]. These authors examined concrete core samples with aggregates containing iron sulfide minerals.…”

Section: Micro X-ray Fluorescence (µXrf)mentioning

confidence: 99%

“…XPS provides information about the element oxidation state and concentration with a detection limit in the parts per million (ppm) range. XPS easily detects small amounts of pyrrhotite, below 0.1% by mass of total S, in a sample [54]. However, XPS analysis requires ultra-high vacuum conditions, and the sample size is limited to a length of up to 5 cm.…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 99%

Concrete damage due to oxidation of pyrrhotite-bearing aggregate: a review

Duchesne

Rodrigues²,

Fournier³

2021

RILEM Tech Lett

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Oxidation of pyrrhotite-bearing aggregates is one of the major causes of concrete damage in numerous buildings in Trois-Rivières in Canada and Connecticut in the USA. In the presence of moisture and oxygen, pyrrhotite oxidizes to generate iron-and sulfate-rich secondary minerals that cause internal sulfate attack. Iron sulfides are accessory minerals of different rock types. The distribution of sulfides is often very heterogeneous in terms of aggregate particles, even at the level of the quarries in which some areas may contain copious amounts than others, which complicates the sampling method. Pyrrhotite is a complex mineral with varying chemical composition, crystallographic structure, and specific surface area. These factors influence the reactivity of pyrrhotite. Therefore, it is challenging to control the quality of the aggregate sources. In this study, recent advances in the identification and quantification of pyrrhotite to diagnose complicated cases are presented, and a performance-based approach for the quality control of new sources of aggregates is introduced. The performance-based approach is preferred because it eliminates the influence of the oxidation of pyrrhotite.

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Study of aggregate samples with iron sulfides through micro X-ray fluorescence (μXRF) and X-ray photoelectron spectroscopy (XPS)

Cited by 13 publications

References 19 publications

Surface Chemistry Analysis of Carbon Nanotube Fibers by X‐Ray Photoelectron Spectroscopy

Surface Chemistry Analysis of Carbon Nanotube Fibers by X‐Ray Photoelectron Spectroscopy

Structural Diagnosis of a Concrete Dam with Cracking and High Nonrecoverable Displacements

Concrete damage due to oxidation of pyrrhotite-bearing aggregate: a review

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