Granular Media

Granular media, from powders to microbeads, are widely present in many industrial sectors, first and foremost in that of concretes and cements. They are multiphasic mediums with a granular solid phase in a liquid to pasty matrix.

The DAET technology has great potential for the characterization of granular media, whether static (grain size influence) or subject to evolving processes:
- Mechanical (compaction, sedimentation...),
- Chemical (polymerization, influence of a set retarder...).

 

Diagramme DAET contact entre billes

The graphs of figure opposite represent acoustical rheograms of a granular medium, consisting of glass microbeads in contact with each other (right graph) and the same medium slightly weakly compacted (left graph). The presence of contact between microbeads significantly increases the observed levels of nonlinearity: TOFM increase, exclusively positive TOFM, hysteresis, dependence on the pressure amplitude.

Technology shows great sensitivity to micro-inhomogeneities (contact between grains, microcracks, damage, microbubbles ...) thus offering the possibility of other interesting applications.