The ongoing ecological crises impose inevitable changes in society’s organization and development.
Construction field being very one of the highest energy and mineral raw-material consuming, new
processes are being intensively investigated to reduce building environmental impact.
In this context, we are interested in the potential of raw earth material for both construction and
renovation. Indeed, this material requires little transport energy (it is available on many building sites),
little manufacturing one (no heating at 1500 °C like for cement), and therefore has low carbon
emission. In addition, it is fully recyclable and thus fuels circular economy. Raw earth has, however, a
significant disadvantage: its sensitivity to liquid water has a direct effect on its consistency. Indeed, it
can pass from fragile to plastic state, and therefore undergo significant decrease of rigidity or strength.
This behaviour is being investigated at the material scale and for a particular earth at LOCIE (El Hajjar
et al.k 2018) through unsaturated soil mechanics approach. However, several questions remain open:
- How can the coupled behaviour be experimentally quantified at the larger scale (structural
element as pile or wall at the scale 1⁄2) and for non uniform hydric states? A particular focus
will concern the effect of hydric cycles on the behaviour. Another important point would
be to compare 2 different earths.
- Would it be possible to numerically predict this effect of water ingress on the mechanical
behaviour at a large scale? The main challenge of such a model would be to adapt soil
mechanics models for buildings.
- Finally, would it be possible to apply the experimental and numerical approach to a real
existing building? The objective aimed is to determine whether the selected construction
would be far or not from instable state.