Influence of accelerated aging on the properties of hemp concretes

The use of vegetal concretes, such as hemp concrete, is growing for building insulation. They are constituted by vegetal aggregates embedded in a mineral binder. Hemp concretes are multifunctional materials: they have interesting thermal and acoustical performances and their hygrothermal behavior enables a natural moisture regulation. Currently, their use is limited by their lack of guarantees in terms of durability. This paper focuses on the influence of 75 days of wetting and drying cycles on hemp concrete properties. It is shown that this aging induces modifications of the porosity of the materials and of their skeleton density. However, these evolutions of microstructure are not sufficient to lead to modifications of thermal and acoustical performances. This work has also shown that mold growth occurs when the relative humidity is high (98% RH) and when the pH of the binder has decreased due to its carbonation reaction