Effect of anisotropy on thermal and hygric properties of hemp composite

Author(s): Florence Collet, Sylvie Pretot, Brahim Mazhoud, Christophe Lanos
Paper category: Proceedings
Book title: SynerCrete’18: Interdisciplinary Approaches for Cement-based Materials and Structural Concrete: Synergizing Expertise and Bridging Scales of Space and Time Vol. 1 & 2
Editor(s): Miguel Azenha, Dirk Schlicke, Farid Benboudjema, Agnieszka Jędrzejewska
ISBN: 978-2-35158-202-2
e-ISBN: 978-2-35158-203-9
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 493-498
Total Pages: 6
Language : English

Abstract: This study investigates the effect of anisotropy on thermal and hygric properties of hemp - clay composite.
The clay based binder is made of fines from aggregate washing mud. It is stabilized with 5% of Portland cement and 5% of lime based binder (Thermo“). The aggregates are CAVAC Biofibat“ hemp shiv. The hemp to binder mass ratio is 0.5, representative of wall formulation. The specimens are produced by casting with successive layers, compacted at 0.1 MPa. The density of hemp-clay composites is about 445 kg/m3 after stabilization at (23°C, 50%RH).
The thermal conductivity is measured with a hot wire at dry state. The measurements are performed placing the wire in planes perpendicular to or parallel to the compaction direction. The anisotropy induces 16.8 % of discrepancy between the two measurement directions. The moisture buffer value (MBV) is measured following the Nordtest protocol. After stabilization at 23°C, 50 %RH, the specimens are exposed to daily cyclic variations (8 hours at 75 %RH , 16 hours at 33 %RH). The MBV is calculated from the mass variation through the exposed surface under relative humidity step. The anisotropy induces 27 % of discrepancy between moisture flux parallel and perpendicular to the compaction direction.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00