Three transverse projects have started in Fall 2016.
- Porous, bio-sourced and sustainable materials for civil engineering
Many building materials, in particular biosourced materials, are porous multi-scale materials: wooden concretes, hemp concretes, concretes with recycled concretes, mud (water-clay combined with vegetable fibers) and wood. These materials have, depending on the case, interesting thermal, hygrometric or acoustic properties, probably linked to their particular structures. The performance from a thermal, acoustic and mass transfer constitue the key criteria in the design of materials and structures. This is particularly the case for humidity transfers (moisture adsorption-restitution). Moreover, the material properties may change in the short or long term due to the mass transfer (soaking and drying cycles, particle transport, dissolution, transport and accumulation of ions, etc.). This is the question of the durability of the material.However, the precise origin of most of these properties of the materials is still not well known. One of the objectives of the project is to have a better understanding of the transfer phenomena in these materials and the microstructural origin of their physical properties in order to formulate the materials more pertinently, or even to invent new materials or more versatile.This project is supported by the complementary expertise of three laboratories: MSME, Navier and ICMPE. It is positioned on two growth themes supported by the LabEx, which are those of the multi-scale porous materials and bio-based materials for civil engineering. The general approach of this project is to develop new methodologies for developing porous and/or bio-based materials, to study via experimental and numerical methods the mechanical, acoustic, thermal properties as well as the transfer properties of these materials according to their microstructures. The characterization techniques associated with modeling studies would enable the link the behavior of materials with idealized microstructures to that of real materials in order to bring out the most promising behavior in the context of the required applications.The work carried out within the framework of this project revolves around two PhD theses and two post-docs. The PhD theses will concentrate on the study of the various physical properties of model porous media prepared according to new techniques and totally bio-sourced materials, particularly bi-porous media having a controlled functionality on the surface of the pores. The approach developed as part of the first one’s PhD thesis, is mainly dedicated to the development of innovative bi-porous systems of which the porosity, the degree of interconnectivity and hydrophilic pores are controlled. The second axe of research, developed as part of the second one PhD thesis is focus on the development and characterization of epoxy resins photo-crosslinked from bio-based building blocks.Additionally, a post-doc is mainly dedicated to the study of the physics of water transfers in softwood. This post doc will complement the results obtained from previously in the framework of the PhD thesis supported by Labex (Axis 2 PhD M. Zhou) on the physics of water transfers in hardwood. This work also made it possible to obtain a PhD thesis funded by the DIM-RESPORE. All these results centered on wood, material of choice in the construction, make it possible to enrich strongly the research developed in the framework of this transverse project.
The second post-doc (see open positions) is entirely devoted to the modeling of the effective properties of materials developed in the framework of this transverse project. The aim is to model the properties of these materials, to compare the predictions of these models with the data, in order to generalize the conclusions drawn from the initial experimental and physical approach and to study their behavior over time (durability).
- Multi-scale analysis of microcracking in civil engineering and geo-materials
The main objectives of the project deal with (a) the prediction of strength properties in new construction materials; (b) the understanding of damage phenomena in cementitious materials at small scales and (c) the prediction of microcracking and localization in geologic and civil engineering materials (clay rocks, concrete) with e.g. applications to storage of nuclear waste, geothermic tank, etc.
The project involves 1 defended PhD, 2 completed Post-docs, 4 ongoing PhD theses and 1 ongoing post-doc.
In Thanh Tung Nguyen’s PhD, the modeling of damage in concrete and cementitious materials combining simulations/imaging experiments and in situ testing has been studied. The extension of advanced crack simulation technique (phase field method) to hydraulic fracture has been investigated in Liang Xia’s post-doc. A study of cracking at the atomistic scale using reactive and non-reactive potential has been investigated in Ignacio Tejada’s post-doc. This work has been followed by Sabri’s Soughir’s PhD where the origin of failure due to instabilities at the atomistic scale has been studied. In Youssouf Abdallah’s PhD, the modeling of thermo-hydro-mechanical behavior and microstructure evolutions of carbonated rocks at high temperatures and pressures is proposed. The phD thesis of Darith Hun deals with the desiccation cracking in clay including modeling, simulation and stochastic modeling. This thesis is done jointly with the post-doc of Abdellali Dadda where experimental data of desiccation cracks in clays are provided. Another related PhD thesis (Vinh Hoang Tan le) deals with the modeling of microcracking in heterogeneous heterogeneous materials with analytical methods including de-bounding interfacial models.
This transverse project has led to (September 2018): 10 papers in international journals, 32 communications in conferences, 1 book chapter and 7 invited presentations.
- Étude à échelle microscopique des propriétés rhéophysiques de matériaux modèles par l’analyse de trajectoires de particules multiples et de l’interaction entre deux particules isolées
(to be completed)