Physico-chemical modifications of the interactions between hemp fibres and a lime mineral matrix: impacts on mechanical properties of mortars

Marianne Le Troëdec (1) , Claire Peyratout (1) , Thierry Chotard (1) , Jean-Pierre Bonnet (1) , Agnès Smith (1) , René Guinebretière (2)

1 GEMH - Groupe d'Etudes des Matériaux Hétérogènes
2 Axe 3 : organisation structurale multiéchelle des matériaux

In order to understand the physico-chemical mechanisms governing interactions between hemp fibres and a lime-based mineral matrix, the consequences of various chemical treatments onto hemp fibres characteristics were measured using scanning electron microscopy, thermal analysis, X-ray diffraction and FTIR spectroscopy. Secondly, effects of these treatments on the mechanical properties of lime mortars incorporating the chemically modified fibres were evaluated using 3 point bending tests. NaOH and EDTA treatments increase the crystallinity index of hemp fibres and increase the experimental rigidity of lime/natural fibres mortars. Treatments with polyethylene imine and a saturated lime solution do not induce any significant changes onto the mechanical properties. These results show that some specific chemical treatments have an impact onto the hemp/lime interfaces quality. The elaborated composite materials exhibit a higher rigidity and an improvement of the matrix /fibre charge transfer. However, the rupture stress is only slightly modified due to a relatively low fibre volumic content (10 %).

Mots clés: natural fibre; composites; surface treatment; mechanical properties

Domaines: Matériaux

Marianne Le Troëdec, Claire Peyratout, Thierry Chotard, Jean-Pierre Bonnet, Agnès Smith, et al.. Physico-chemical modifications of the interactions between hemp fibres and a lime mineral matrix: impacts on mechanical properties of mortars. 10th International Conference of the European Ceramic Society, Jun 2007, Berlin, Germany. pp.451-456. ⟨hal-00282100⟩