Multiscale poromechanics of wet cement paste
Name
10652.full.pdf
Description
Published version
Size
1.81 MB
Format
Adobe PDF
Checksum (MD5)
f52dc5f40d869e9dfa2445d37eef592b
Author(s)
Zhou, Tingtao
Ioannidou, Katerina
Ulm, Franz-Josef
Bazant, Martin Z
Pellenq, RJ-M
Date Issued
2019
Journal
Proceedings of the National Academy of Sciences of the United States of America
Publisher
Proceedings of the National Academy of Sciences
Version
Final published version
Abstract
© 2019 National Academy of Sciences. All rights reserved. Capillary effects, such as imbibition drying cycles, impact the mechanics of granular systems over time. A multiscale poromechanics framework was applied to cement paste, which is the most common building material, experiencing broad humidity variations over the lifetime of infrastructure. First, the liquid density distribution at intermediate to high relative humidity is obtained using a lattice gas density functional method together with a realistic nanogranular model of cement hydrates. The calculated adsorption/desorption isotherms and pore size distributions are discussed and compare well with nitrogen and water experiments. The standard method for pore size distribution determination from desorption data is evaluated. Second, the integration of the Korteweg liquid stress field around each cement hydrate particle provided the capillary forces at the nanoscale. The cement mesoscale structure was relaxed under the action of the capillary forces. Local irreversible deformations of the cement nanograins assembly were identified due to liquid-solid interactions. The spatial correlations of the nonaffine displacements extend to a few tens of nanometers. Third, the Love-Weber method provided the homogenized liquid stress at the micrometer scale. The homogenization length coincided with the spatial correlation length of nonaffine displacements. Our results on the solid response to capillary stress field suggest that the micrometer-scale texture is not affected by mild drying, while nanoscale irreversible deformations still occur. These results pave the way for understanding capillary phenomenainduced stresses in heterogeneous porous media ranging from construction materials to hydrogels and living systems.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Department of Mathematics
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1073/pnas.1901160116
