We focus on water transport and phase changes in porous media encountered in construction materials, with a special emphasis on bio-based materials such as wood, hempcrete or insulating boards of fibers of flax, cotton, wheat, wood, coir,…, whose use significantly contributes to the reduction of CO2 emissions. We are especially interested in the wetting, drying and hygrothermal properties of these systems which are able to absorb (and release) a large amount of vapor in the form of “bound water” (see Ph. Coussot course (Biobased construction materials) in Master SMCD (https://ecoledesponts.fr/master-smcd-science-materiaux-construction-durable)). Our research work aims at understanding the underlying physics of these processes in order to describe them macroscopically with relevant measurable parameters. We take great advantage of unique equipments and developments (Magnetic Resonance Imaging of bound water, Dynamic NMR Relaxometry,…) of the NMR team of Laboratoire Navier (https://navier-lab.fr/), which in particular allow to follow and quantify the spatial distribution of water in its different states inside such non-transparent materials.
A former research activity concerns the rheological behavior of pastes, i.e. yield stress fluids, such as paints, cements, muds, foams, emulsions, toothpastes, gels, which can flow only when a stress larger than a critical value is applied. These fluids were studied under different flow conditions: adhesion, dripping, extrusion, dip coating, sedimentation, two-phase flow instabilities, free surface flow instability, flow through porous medium. The Rheophysics and Porous media Team (https://navier-lab.fr/la-recherche/rheophysique-et-milieux-poreux/) of Laboratoire Navier covers this activity with a special emphasis on the mechanical properties of these materials explained by the internal physico-chemical interactions between elementary components.