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La Bella M, Besselink R, Wright JP, Van Driessche AES, Fernandez-Martinez A, Giacobbe C. Hierarchical synchrotron diffraction and imaging study of the calcium sulfate hemihydrate-gypsum transformation. J Appl Crystallogr 2023; 56:660-672. [PMID: 37284277 PMCID: PMC10241062 DOI: 10.1107/s1600576723002881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/26/2023] [Indexed: 06/08/2023] Open
Abstract
The mechanism of hydration of calcium sulfate hemihydrate (CaSO4·0.5H2O) to form gypsum (CaSO4·2H2O) was studied by combining scanning 3D X-ray diffraction (s3DXRD) and phase contrast tomography (PCT) to determine in situ the spatial and crystallographic relationship between these two phases. From s3DXRD measurements, the crystallographic structure, orientation and position of the crystalline grains in the sample during the hydration reaction were obtained, while the PCT reconstructions allowed visualization of the 3D shapes of the crystals during the reaction. This multi-scale study unfolds structural and morphological evidence of the dissolution-precipitation process of the gypsum plaster system, providing insights into the reactivity of specific crystallographic facets of the hemihydrate. In this work, epitaxial growth of gypsum crystals on the hemihydrate grains was not observed.
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Affiliation(s)
- Michela La Bella
- European Synchrotron Radiation Facility, 71 Avenue Des Martyrs, Grenoble 38040, France
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble 38000, France
| | - Rogier Besselink
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble 38000, France
| | - Jonathan P. Wright
- European Synchrotron Radiation Facility, 71 Avenue Des Martyrs, Grenoble 38040, France
| | - Alexander E. S. Van Driessche
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble 38000, France
- Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC-University of Granada, Armilla 18100, Spain
| | | | - Carlotta Giacobbe
- European Synchrotron Radiation Facility, 71 Avenue Des Martyrs, Grenoble 38040, France
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Vamvakeros A, Coelho AA, Matras D, Dong H, Odarchenko Y, Price SWT, Butler KT, Gutowski O, Dippel AC, Zimmermann M, Martens I, Drnec J, Beale AM, Jacques SDM. DLSR: a solution to the parallax artefact in X-ray diffraction computed tomography data. J Appl Crystallogr 2020. [DOI: 10.1107/s1600576720013576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A new tomographic reconstruction algorithm is presented, termed direct least-squares reconstruction (DLSR), which solves the well known parallax problem in X-ray-scattering-based experiments. The parallax artefact arises from relatively large samples where X-rays, scattered from a scattering angle 2θ, arrive at multiple detector elements. This phenomenon leads to loss of physico-chemical information associated with diffraction peak shape and position (i.e. altering the calculated crystallite size and lattice parameter values, respectively) and is currently the major barrier to investigating samples and devices at the centimetre level (scale-up problem). The accuracy of the DLSR algorithm has been tested against simulated and experimental X-ray diffraction computed tomography data using the TOPAS software.
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Ma B, Fernandez-Martinez A, Wang K, Madé B, Hénocq P, Tisserand D, Bureau S, Charlet L. Selenite Sorption on Hydrated CEM-V/A Cement in the Presence of Steel Corrosion Products: Redox vs Nonredox Sorption. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2344-2352. [PMID: 31971374 DOI: 10.1021/acs.est.9b06876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Reinforced cementitious structures in nuclear waste repositories will act as barriers that limit the mobility of radionuclides (RNs) in case of eventual leakage. CEM-V/A cement, a ternary blended cement with blast furnace slag (BFS) and fly ash (FA), could be qualified and used in nuclear waste disposal. Chemical interactions between the cement and RNs are critical but not completely understood. Here, we combined wet chemistry methods, synchrotron-based X-ray techniques, and thermodynamic modeling to explore redox interactions and nonredox sorption processes in simulated steel-reinforced CEM-V/A hydration systems using selenite as a molecular probe. Among all of the steel corrosion products analyzed, only the addition of Fe0 can obviously enhance the reducing ability of cement toward selenite. In comparison, steel corrosion products showed stronger reducing power in the absence of cement hydrates. Selenium K-edge X-ray absorption spectroscopy (XAS) revealed that selenite immobilization mechanisms included nonredox inner-/outer-sphere complexations and reductive precipitations of FeSe and/or Se(0). Importantly, the hydrated pristine cement showed a good reducing ability, driven by ferrous phases and (bi)sulfides (as shown by sulfur K-edge XAS) originated from BFS and FA. The overall redox potential imposed by hydrated CEM-V/A was determined, hinting to a redox shift in underground cementitious structures.
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Affiliation(s)
- Bin Ma
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre , 38000 Grenoble , France
- Laboratory for Concrete & Construction Chemistry , Swiss Federal Laboratories for Materials Science and Technology (Empa) , 8600 Dübendorf , Switzerland
| | | | - Kaifeng Wang
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre , 38000 Grenoble , France
- Decommissioning Engineering Technology Center , China Institute of Atomic Energy , 102413 Beijing , China
| | - Benoît Madé
- Andra , 1/7 rue Jean Monnet, Parc de la Croix Blanche , 92298 Châtenay-Malabry Cedex , France
| | - Pierre Hénocq
- Andra , 1/7 rue Jean Monnet, Parc de la Croix Blanche , 92298 Châtenay-Malabry Cedex , France
| | - Delphine Tisserand
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre , 38000 Grenoble , France
| | - Sarah Bureau
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre , 38000 Grenoble , France
| | - Laurent Charlet
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre , 38000 Grenoble , France
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Cuesta A, De la Torre ÁG, Santacruz I, Diaz A, Trtik P, Holler M, Lothenbach B, Aranda MAG. Quantitative disentanglement of nanocrystalline phases in cement pastes by synchrotron ptychographic X-ray tomography. IUCRJ 2019; 6:473-491. [PMID: 31098028 PMCID: PMC6503921 DOI: 10.1107/s2052252519003774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/19/2019] [Indexed: 05/25/2023]
Abstract
Mortars and concretes are ubiquitous materials with very complex hierarchical microstructures. To fully understand their main properties and to decrease their CO2 footprint, a sound description of their spatially resolved mineralogy is necessary. Developing this knowledge is very challenging as about half of the volume of hydrated cement is a nanocrystalline component, calcium silicate hydrate (C-S-H) gel. Furthermore, other poorly crystalline phases (e.g. iron siliceous hydrogarnet or silica oxide) may coexist, which are even more difficult to characterize. Traditional spatially resolved techniques such as electron microscopy involve complex sample preparation steps that often lead to artefacts (e.g. dehydration and microstructural changes). Here, synchrotron ptychographic tomography has been used to obtain spatially resolved information on three unaltered representative samples: neat Portland paste, Portland-calcite and Portland-fly-ash blend pastes with a spatial resolution below 100 nm in samples with a volume of up to 5 × 104 µm3. For the neat Portland paste, the ptychotomographic study gave densities of 2.11 and 2.52 g cm-3 and a content of 41.1 and 6.4 vol% for nanocrystalline C-S-H gel and poorly crystalline iron siliceous hydrogarnet, respectively. Furthermore, the spatially resolved volumetric mass-density information has allowed characterization of inner-product and outer-product C-S-H gels. The average density of the inner-product C-S-H is smaller than that of the outer product and its variability is larger. Full characterization of the pastes, including segmentation of the different components, is reported and the contents are compared with the results obtained by thermodynamic modelling.
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Affiliation(s)
- Ana Cuesta
- Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071-Malaga, Spain
| | - Ángeles G. De la Torre
- Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071-Malaga, Spain
| | - Isabel Santacruz
- Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071-Malaga, Spain
| | - Ana Diaz
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Pavel Trtik
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Faculty of Civil Engineering, Czech Technical University in Prague, 166 29 Prague, Czech Republic
| | - Mirko Holler
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Barbara Lothenbach
- EMPA, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Miguel A. G. Aranda
- Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071-Malaga, Spain
- ALBA Synchrotron, Carrer de la Llum 2-26, E-08290 Cerdanyola del Vallès, Barcelona, Spain
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