Behavior of a hemp-based concrete wall under dynamic thermal and hygric solicitations

•Experiments and numerical results on a hemp-based wall are provided.•Tests were made in a bi-climatic chamber under dynamic thermo-hygric conditions.•Temperature and vapor pressure profiles were measured in time through the wall.•A HAM model was validated at wall scale highlighting the moisture dam...

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Bibliographic Details
Published in:Energy and buildings 2021-02, Vol.232, p.110669, Article 110669
Main Authors: Seng, Billy, Magniont, Camille, Gallego, Sandra, Lorente, Sylvie
Format: Article
Language:English
Subjects:
Bi-climatic chamber
Bio-based materials
Biological materials
Civil Engineering
Concrete blocks
Coupled walls
Dumping
Engineering Sciences
Heat
Heat and moisture transfer
Heat transfer
Hemp
Hemp concrete
Mathematical models
Moisture
Numerical models
Precast concrete
Temperature gradients
Test chambers
Thermal insulation
Transport phenomena
Wall scale
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Summary:•Experiments and numerical results on a hemp-based wall are provided.•Tests were made in a bi-climatic chamber under dynamic thermo-hygric conditions.•Temperature and vapor pressure profiles were measured in time through the wall.•A HAM model was validated at wall scale highlighting the moisture damping ability. Here we document the behavior at wall scale of a hemp-based hygroscopic material under various temperature and moisture dynamic conditions. The wall was made of precast hemp concrete (HC) blocks with air cavities. It was tested within a bi-climatic chamber and monitored thanks to hygrothermal sensors in the wall and in the chambers. The results from an in-house heat and moisture transfer model were compared to the experimental data, using the actual thermal and hygric characteristics of the hemp-based material determined in a previous study. The experiments allowed to demonstrate how the heat and moisture transport phenomena within the wall are coupled, particularly how a temperature difference can be a sufficient driving force for the release of moisture. The work points out the impact of moisture adsorption on heat release and on the temperature changes within the wall. Finally the numerical model served also to the modelling of an equivalent wall made of concrete to help highlighting the moisture dumping capability of the bio-based material, together with its thermal insulation capacity.
ISSN:0378-7788
1872-6178
DOI:10.1016/j.enbuild.2020.110669