@article {622, title = {The Potential of Mean Force concept for bridging (length and time) scales in the modeling of complex porous materials}, journal = {EPJ Web of Conferences}, volume = {140}, year = {2017}, month = {Jun-30-2017}, pages = {Article Number 01009}, abstract = {

We introduce the concept of Potential of Mean Force, PMF, as a way to implement upscaling modeling from the nano-scale to micron-scale. A PMF is a free energy function representing in an effective way the interactions between objects (cement hydrates, clay platelets, etc.) at thermodynamics conditions. The PMF is therefore the key piece of information allowing to coarse-grained Physical-Chemistry information in a meso-scale model formulation. The use of PMF offers a huge computational advantage as it allows a straight up-scaling to the meso-scale while keeping essential interactions information that are the hallmark of Physical-Chemistry processes. Such a coarse-grained modeling integrates atomistic response into inter-particle potentials that fully propagate molecular scale information all the way to the meso-scale.

}, doi = {10.1051/epjconf/201714001009}, url = {http://www.epj-conferences.org/10.1051/epjconf/201714001009}, author = {Katerina Ioannidou and Benoit Carrier and Matthieu Vandamme and Roland Jean-Marc Pellenq}, editor = {Farhang Radja{\"\i} and Saeid Nezamabadi and Luding, S. and Jean-Yves Delenne} } @book {636, title = {Springer Series in Geomechanics and GeoengineeringAdvances in Laboratory Testing and Modelling of Soils and Shales (ATMSS)Measurement of Mechanical Properties of Thin Clay Films and Comparison with Molecular Simulations}, series = {Springer Series in Geomechanics and Geoengineering}, year = {2017}, pages = {78-84}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

Here, we focus on the hydromechanical behavior of self-standing clay films with a thickness of a few dozen microns. We measure their elastic and creep properties and how those properties depend on the interlayer cation and on the relative humidity (or water content). Those experimental results are compared with the elastic and creep behavior of nanometric clay particles, which we characterize by molecular simulations. Significant qualitative differences between the behavior of the clay films and that of the clay particles are observed, which suggests that the hydromechanical behavior of the clay films is significantly impacted by their mesostructure (i.e., by how the clay particles or tactoids are arranged in space). Upscaling the hydromechanical behavior of the clay films from that of the clay particles may be challenging.

}, isbn = {978-3-319-52772-7}, issn = {1866-8755}, doi = {10.1007/978-3-319-52773-410.1007/978-3-319-52773-4_8}, url = {http://link.springer.com/10.1007/978-3-319-52773-4}, author = {Benoit Carrier and Matthieu Vandamme and Roland Jean-Marc Pellenq and Henri Van Damme}, editor = {Ferrari, Alessio and Laloui, Lyesse} } @article {217, title = {Effect of Water on Elastic and Creep Properties of Self-Standing Clay Films}, journal = {Langmuir}, volume = {32}, year = {2016}, month = {Feb-09-2016}, pages = {1370 - 1379}, abstract = {

We characterized experimentally the elastic and creep properties of thin self-standing clay films, and how their mechanical properties evolved with relative humidity and water content. The films were made of clay montmorillonite SWy-2, obtained by evaporation of a clay suspension. Three types of films were manufactured, which differed by their interlayer cation: sodium, calcium, or a mixture of sodium with calcium. The orientational order of the films was characterized by X-ray diffractometry. The films were mechanically solicited in tension, the resulting strains being measured by digital image correlation. We measured the Young\&$\#$39;s modulus and the creep over a variety of relative humidities, on a full cycle of adsorption-desorption for what concerns the Young\&$\#$39;s modulus. Increasing relative humidity made the films less stiff and made them creep more. Both the elastic and creep properties depended significantly on the interlayer cation. For the Young\&$\#$39;s modulus, this dependence must originate from a scale greater than the scale of the clay layer. Also, hysteresis disappeared when plotting the Young\&$\#$39;s modulus versus water content instead of relative humidity. Independent of interlayer cation and of relative humidity greater than 60\%, after a transient period, the creep of the films was always a logarithmic function of time. The experimental data gathered on these mesoscale systems can be of value for modelers who aim at predicting the mechanical behavior of clay-based materials (e.g., shales) at the engineering macroscopic scale from the one at the atomistic scale, for them to validate the first steps of their upscaling scheme. They provide also valuable reference data for bioinspired clay-based hybrid materials.

}, issn = {0743-7463}, doi = {10.1021/acs.langmuir.5b03431}, author = {Benoit Carrier and Matthieu Vandamme and Roland Jean-Marc Pellenq and Bornert, Michel and Ferrage, Eric and Hubert, Fabien and Henri Van Damme} } @proceedings {333, title = {Creep of Clay: Numerical Results at the Scale of a Layer and Experimental Results at the Scale of Thin Self-Standing Films}, journal = {10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete StructuresCONCREEP 10}, volume = {CONCREEP 10: MECHANICS AND PHYSICS OF CREEP, SHRINKAGE, AND DURABILITY OF CONCRETE AND CONCRETE STRUCTURES }, year = {2015}, month = {Sep-17-2015}, pages = {531-536}, publisher = {American Society of Civil Engineers}, address = {September 21{\textendash}23, 2015, Vienna, AustriaReston, VA}, abstract = {

This work focuses on the creep of clay-based materials, which exhibit significant analogies with cement-based materials. Here, we studied the creep of clay at two scales and with two techniques: numerically (with molecular simulations) at the scale of a clay layer (nm), and experimentally at the scale of thin self-standing clay films (few dozen m). At the scale of the clay layer, numerical simulations showed that the shear rate was constant over time and an affine function of the shear stress. Creep experiments showed that, after a transient period, the creep function of our thin self-standing clay films was a logarithmic function of time. A comparison of the results obtained at the two scales shows that the origin of the logarithmic feature of clay creep must at least partly originate from a scale greater than that of an individual clay layer. By analogy, such result is likely to hold for cementitious materials, which are also known to creep logarithmically with respect to time in the long term: the origin of this logarithmic feature is likely to stem at least partly from a scale greater than the scale of an individual C-S-H layer.

}, doi = {10.1061/978078447934610.1061/9780784479346.064}, author = {Benoit Carrier and Matthieu Vandamme and Roland Jean-Marc Pellenq and Henri Van Damme}, editor = {Hellmich, Christian and Pichler, Bernhard and Kollegger, Johann} } @article {114, title = {Elastic Properties of Swelling Clay Particles at Finite Temperature upon Hydration}, journal = {Journal of Physical Chemistry C}, volume = {118}, year = {2014}, month = {May-01-2014}, pages = {8933-8943}, type = {Article}, abstract = {
Abstract Image

The knowledge of mechanical properties of swelling clays on the scale of the clay layer is of crucial importance to build predictive hydromechanical macroscopic constitutive laws in a bottom-up approach. In this work, we computed the elastic properties of particles of a swelling clay (i.e., montmorillonite) by molecular dynamics simulations. Because of the softness of the material in the direction orthogonal to the clay layer with increasing water content, the computation of the whole stiffness tensor was not trivial: we needed to implement the elastic bath method,1 which allows us to attenuate thermal strains and compute the stiffness via strain fluctuations in isothermal\–isobaric simulations. We investigated the effect of water content, temperature, and the interlayer cation on the elastic properties of swelling clays. In particular, we showed that the out-of-plane stiffness coefficients computed at 300 K differed significantly from the same coefficients computed at 0 K. The out-of-plane coefficients were very sensitive to both temperature and water content. In contrast, the dependence of the in-plane coefficients to temperature was slight. Moreover, the decrease of the in-plane coefficients with water content could be entirely explained by the change of geometry of the system due to the swelling of the interlayer space. The interlayer cation impacted the elastic properties of montmorillonite only in the driest states.

}, issn = {1932-7447}, doi = {10.1021/jp412160e}, author = {Benoit Carrier and Matthieu Vandamme and Roland Jean-Marc Pellenq and Henri Van Damme} } @article {46, title = {ESEM Study of the Humidity-Induced Swelling of Clay Film}, journal = {Langmuir}, volume = {29}, year = {2013}, month = {Oct-02-2013}, pages = {12823{\textendash}12833}, abstract = {
Abstract Image

We measured the humidity-induced swelling of thin self-standing films of montmorillonite clay by a combination of environmental scanning electron microscopy (ESEM) and digital image correlation (DIC). The films were about 40 \μm thick. They were prepared by depositing and evaporating a suspension of clay and peeling off the highly oriented deposits. The rationale for creating such original samples was to obtain mesoscopic samples that could be used to bridge experimentally the gap between the scale of the clay layer and the engineering scale of a macroscopic clay sample. Several montmorillonite samples were used: the reference clay Swy-2, the same clay homoionized with sodium or calcium ions, and a sodium-exchanged Cloisite. The edges of the clay films were observed by ESEM at various relative humidity values between 14\% and 95\%. The ESEM images were then analyzed by DIC to measure the swelling or the shrinkage of the films. We also measured the adsorption/desorption isotherms by weighing the film samples in a humidity-controlled environment. In order to analyze our results, we compared our swelling/shrinkage and adsorption/desorption data with previously published data on the interlayer spacing obtained by X-ray diffraction and with numerical estimates of the interlayer water obtained by molecular dynamics simulation. The swelling and the hysteresis of this swelling were found to be comparable for the overall macroscopic films and for the interlayer space. The same correspondence between film and interlayer space was observed for the amount of adsorbed water. This suggests that, in the range of relative humidities values explored, the films behave like freely swelling oriented stacks of clay layers, without any significant contribution from the mesoporosity. The relevance of this result for the behavior of clayey sedimentary rocks and the differences with the behavior of nonoriented samples (powders or compacted powders) are briefly discussed.

}, doi = {10.1021/la402781p}, author = {Benoit Carrier and Wang, Linlin and Matthieu Vandamme and Roland Jean-Marc Pellenq and Bornert, Michel and Tanguy, Alexandre and Henri Van Damme} }