Optimization of the linseed oil treatment of flax fibres: influence on fresh properties of fibrereinforced mortars
For several years, many studies have focused on the mix-design and characterization of cementitious composites reinforced with plant fibres. It appears that in the fresh state, the morphology and the hydrophilic nature of these fibres significantly affect the rheology of the material. In the hardened state, the mechanical performance of the composites is lower than that of the composites including synthetic fibres. These low mechanical performances are mainly due to the weak fibre/matrix interface. Indeed, the high-water absorption capacity causes swelling/shrinkage of the fibre within the matrix, which subsequently leads to a lack of fibre/matrix bond. This work proposes to study the influence of a coating treatment with linseed oil applied to flax fibres on the properties of cementitious composites. The first part of this study deals with the optimisation of this treatment. The second part focuses on the effect of this treatment on the fresh state properties of the composite. The results showed a strong improvement in the workability of the treated fibre composites. A pronounced effect of the linseed oil treatment on air content was noted for high fibre content.