Micro-macro experimental investigation into the thermomechanical volumetric response of non-active clay
File(s)
Published version
Author(s)
Casarella, Angela
Tarantino, Alessandro
di Donna, Alice
Type
Journal Article
Abstract
The thermomechanical behaviour of clayey soils is critical for various geotechnical and geoenvironmental applications, yet the underlying particle-scale mechanisms remain debated. This study presents a multi-scale investigation into the microstructural origins of the distinct volumetric responses observed in normally consolidated (NC) and overconsolidated (OC) clays subjected to thermal loading. Temperature-controlled isotropic compression tests were coupled with Mercury Intrusion Porosimetry (MIP) on reconstituted samples of Speswhite Kaolin clay.
The macroscopic results confirm that NC non-active clay exhibits irreversible contraction upon heating, while highly OC non-active clay undergoes reversible expansion. MIP analyses reveal that thermal contraction in NC kaolin is linked to a reduction in macropore volume, driven by irreversible slippage at edge-to-face particle contacts due to a temperature-induced weakening of electrochemical attractions. In contrast, the thermal expansion of OC clay is associated with an elastic increase in the separation distance between face-to-face particle configurations.
These findings provide direct experimental support for recent particle-scale modelling based on 3D DLVO interactions and demonstrate that thermal loading under constant stress activates the same microscale processes that drive mechanically induced volumetric deformation. The high level of experimental control makes the resulting dataset particularly suited for validation of particle-scale numerical models and for informing constitutive formulations that explicitly link thermomechanical behaviour to interparticle forces and contact mechanics.
The macroscopic results confirm that NC non-active clay exhibits irreversible contraction upon heating, while highly OC non-active clay undergoes reversible expansion. MIP analyses reveal that thermal contraction in NC kaolin is linked to a reduction in macropore volume, driven by irreversible slippage at edge-to-face particle contacts due to a temperature-induced weakening of electrochemical attractions. In contrast, the thermal expansion of OC clay is associated with an elastic increase in the separation distance between face-to-face particle configurations.
These findings provide direct experimental support for recent particle-scale modelling based on 3D DLVO interactions and demonstrate that thermal loading under constant stress activates the same microscale processes that drive mechanically induced volumetric deformation. The high level of experimental control makes the resulting dataset particularly suited for validation of particle-scale numerical models and for informing constitutive formulations that explicitly link thermomechanical behaviour to interparticle forces and contact mechanics.
Date Issued
2026-06-01
Date Acceptance
2026-04-11
Citation
Geomechanics for Energy and the Environment, 2026, 46
ISSN
2352-3808
Publisher
Elsevier BV
Journal / Book Title
Geomechanics for Energy and the Environment
Volume
46
Copyright Statement
© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
100831
Date Publish Online
2026-04-13