Kabore, Aguerata, Bendouma, Mathieu et Ouellet-Plamondon, Claudiane.
2025.
« Numerical analysis of heavy cob walls’ hygrothermal behavior ».
Energy and Buildings, vol. 331.
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Résumé
The development of building envelope systems with low carbon footprint materials and improved hygrothermal properties is still in progress. For geosourced materials, one of the main objectives is to achieve optimal hygrothermal efficiency. Cob, a material made of clay, plant fibres, and water, stands out for its low carbon footprint and ease of application on timber-framed building structures. The main goal of this study is to assess the hygrothermal performance of eight heavy cob wall systems in eight cities in African, European, and American climates. An extensive laboratory characterization is carried out to measure the hygrothermal properties of each material. The thermal conductivity obtained after the measurements is 0.75 W/m.K and 0.87 W/m.K for red and beige clay samples, respectively, 0.52 W/m.K for the cob with 3 % fibres, and 0.2 W/m.K for the cob with 6 % fibres samples, and the porosity rates are 21, 20, 37, and 45 for the clay and cob samples, respectively. The hygrothermal simulation showed that the interior temperature of the walls made of cob with 6 % fibres and a thickness of 25 cm remained stable, regardless of external climate variations. Applying beige clay plasters to the exterior and interior surfaces of cob walls or timber structures improved thermal performance in terms of heating or cooling energy demand but also increased the walls’ moisture absorption. This increased moisture enhances the risk of mold growth within the wall structure. When used as infill materials in timber structures, the simulated composite systems generally exhibit good hygrothermal performance. However, in cold climate zones with high precipitation and heavily clouded skies, the walls may be exposed to risks of mold development. To prevent mold in these walls, install a rain screen or an air/vapor barrier membrane between the plaster and cob. This helps manage moisture and ensures proper wall drying.
| Type de document: | Article publié dans une revue, révisé par les pairs |
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| Professeur: | Professeur Ouellet-Plamondon, Claudiane |
| Affiliation: | Génie de la construction |
| Date de dépôt: | 13 févr. 2025 16:39 |
| Dernière modification: | 04 mars 2025 14:49 |
| URI: | https://espace2.etsmtl.ca/id/eprint/30549 |
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