RT Journal Article
T1 Quantitative disentanglement of nanocrystalline phases in cement pastes by synchrotron ptychographic X-ray tomography
A1 Cuesta-García, Ana María
A1 Gómez-de-la-Torre, María de los  Ángeles
A1 Santacruz-Cruz, María Isabel
A1 Díaz, Ana
A1 Trtik, Pavel
A1 Holler, Mirko
A1 Lothenbach, Barbara
A1 García-Aranda, Miguel Ángel
K1 Cemento Portland
K1 Rayos X, Análisis por
K1 Microestructura
K1 Densidad-Medición
K1 Tomografía
K1 Termodinámica
AB 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 resolutionbelow 100 nm in samples with a volume of up to 5 x 104 mm3. 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.
PB IUCr
YR 2019
FD 2019
LK https://hdl.handle.net/10630/17614
UL https://hdl.handle.net/10630/17614
LA eng
NO IUCrJ (2019). 6, 473–491
NO This work has been supported by MINECO through BIA2014-57658 and BIA2017-82391-R research grants, which are cofunded by FEDER. Instrumentation development was supported by SNF (R’EQUIP, No. 145056,‘OMNY’) and the Competence Centre for Materials Science and Technology (CCMX) of the ETH-Board, Switzerland.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 20 ene 2026