Multidisciplinary approach to assess the durability of hemp concretes

12th Conference on Advanced Building Skins, BERNE, SUISSE, 02-/10/2017 - 03/10/2017To improve the thermal and acoustical insulation of buildings while minimizing the consumption of non-renewable resources, the use of materials containing plant aggregates expands. In France, hemp concrete is frequently used. It is composed of a mineral binder and plant aggregates called hemp shiv. However, its use is still limited by its lack of guarantees in terms of durability. Therefore, the objective of our study is to investigate the durability of these vegetal concretes after accelerated ageing in laboratory. For this, a multiscale and multidisciplinary approach is used. First, different exposure environments, corresponding to the conditions of use of the materials, are chosen: variations of humidity and temperature, growth of molds...Then, the evolution of their functional properties (thermal, acoustical and mechanical behavior) is characterised as a function of time, and is linked to the modification of their physicochemical and microstructural properties. The variations of the global behavior of the material will be related to biological ageing, namely the growth of microorganisms in concretes, or be the result of environmental ageing, corresponding to temperature and humidity variations. As a result, this study will allow the development of technical recommendations both to optimize the durability of bio-based materials and to quantify the lifetime of such materials according to their exposure conditions