TomExTer

The design and optimal use of structural materials, either manufactured or natural, require a detailed knowledge of their microstructure and of the physical mechanisms that are activated when they are subjected to complex thermo-hydro-mecanichal loading histories. Imaging techniques, when combined with so-called “in situ testing” devices, provide a unique way to identify and quantity these mechanisms. Since properties of structural material essentially result from their bulk, full 3D imaging methods able to visualize what is going on inside samples, are of primary interest.

The present TOMEXTER project aims at extending the capacities of the federative X-Ray microtomography platform available at laboratoire Navier (Ecole des ponts, Marne-la-vallée), which has been operating for 12 year and is regularly used by several other partner labs. It consists first in a technical update of the microtomography setup, which will permit to run new scanning procedures and make full use of new generation high definition imaging sensors. In addition, it aims at developping new in situ testing devices compatible with a significantly wider range of sample sizes and loading conditions and levels. It will be possible to investigate natural geomaterials exhibiting centimetric heterogeneities by considering several centimeter-sized samples subjected to large loads (several tons). This will be for instance useful to investigate the properties of porous carbonate rocks or rock salt, in the context of geothermal applications or H2 or CO2 large scale undergroung storage, investigated by the two partner labs (Navier and LMS). On another hand, the detailed analysis of the propagation of individual microcracks within a rock requires the controlled application of very small load increments. Other applications concern bio-based fibrous or foamy materials for thermal and acoustic insulation of buildings (MSME and Navier). The development of microcracks networks in multiphase polymer materials or refractory materials will be investigated by PIMM, as well as the effect of micropores observed in materials manufactured by additive techniques such as selective laser melting. Various metals and polymers will also be investigated by CMAT.