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Grain-scale stress heterogeneity in concrete from in-situ X-ray measurements

Thakur, Mohmad M. ; Henningsson, N. Axel LU ; Engqvist, Jonas LU orcid ; Autran, Pierre Olivier ; Wright, Jonathan P. and Hurley, Ryan C. (2025) In Cement and Concrete Research 190.
Abstract

Concrete features significant microstructural heterogeneity which affects its mechanical behavior. Strain localization in the matrix phase of concrete has received significant attention due to its relation to microcracking and our ability to quantify it with X-ray computed tomography (XRCT). In contrast, stresses in sand and aggregates remain largely unmeasured but remain critical for micromechanics-based theories of failure. Here, we use a combination of in-situ XRCT, 3D X-ray diffraction (3DXRD), and scanning 3DXRD to directly measure strain and stress within sand grains in two samples of mortar containing different sand volume fractions. Our results reveal that, in contrast to inclusion theories from continuum micromechanics,... (More)

Concrete features significant microstructural heterogeneity which affects its mechanical behavior. Strain localization in the matrix phase of concrete has received significant attention due to its relation to microcracking and our ability to quantify it with X-ray computed tomography (XRCT). In contrast, stresses in sand and aggregates remain largely unmeasured but remain critical for micromechanics-based theories of failure. Here, we use a combination of in-situ XRCT, 3D X-ray diffraction (3DXRD), and scanning 3DXRD to directly measure strain and stress within sand grains in two samples of mortar containing different sand volume fractions. Our results reveal that, in contrast to inclusion theories from continuum micromechanics, aggregates feature a broad distribution of average stresses and significant gradients in their internal stress fields. Our work furnishes the first known dataset with these quantitative stress measurements and motivates improvements in micromechanics models for concrete which can capture stress heterogeneity.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
3D X-ray diffraction, Aggregate stresses, Concrete, Heterogeneity, Scanning 3D X-ray diffraction
in
Cement and Concrete Research
volume
190
article number
107789
publisher
Elsevier
external identifiers
  • scopus:85217003537
ISSN
0008-8846
DOI
10.1016/j.cemconres.2025.107789
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025
id
6831bea6-3a87-4a7e-9c21-9582fe7ab865
date added to LUP
2025-02-14 11:33:41
date last changed
2025-02-28 12:29:31
@article{6831bea6-3a87-4a7e-9c21-9582fe7ab865,
  abstract     = {{<p>Concrete features significant microstructural heterogeneity which affects its mechanical behavior. Strain localization in the matrix phase of concrete has received significant attention due to its relation to microcracking and our ability to quantify it with X-ray computed tomography (XRCT). In contrast, stresses in sand and aggregates remain largely unmeasured but remain critical for micromechanics-based theories of failure. Here, we use a combination of in-situ XRCT, 3D X-ray diffraction (3DXRD), and scanning 3DXRD to directly measure strain and stress within sand grains in two samples of mortar containing different sand volume fractions. Our results reveal that, in contrast to inclusion theories from continuum micromechanics, aggregates feature a broad distribution of average stresses and significant gradients in their internal stress fields. Our work furnishes the first known dataset with these quantitative stress measurements and motivates improvements in micromechanics models for concrete which can capture stress heterogeneity.</p>}},
  author       = {{Thakur, Mohmad M. and Henningsson, N. Axel and Engqvist, Jonas and Autran, Pierre Olivier and Wright, Jonathan P. and Hurley, Ryan C.}},
  issn         = {{0008-8846}},
  keywords     = {{3D X-ray diffraction; Aggregate stresses; Concrete; Heterogeneity; Scanning 3D X-ray diffraction}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Cement and Concrete Research}},
  title        = {{Grain-scale stress heterogeneity in concrete from in-situ X-ray measurements}},
  url          = {{http://dx.doi.org/10.1016/j.cemconres.2025.107789}},
  doi          = {{10.1016/j.cemconres.2025.107789}},
  volume       = {{190}},
  year         = {{2025}},
}