Preliminary assessment of alkali-resistant flax based meshes for reinforcing cementitious composites

The production of textile-reinforced concrete (TRC) requires less materials and energy in comparison with conventional concrete reinforced with steel rebars, which draws some solutions towards the production of net zero concrete that the Cement and Concrete Industry sector should reach by 2050. To go one step further, this study investigates the development of flax based meshes as basic components for a reinforcement grid in cementitious materials. Flax strands and hybrid strands (combination of flax strands and glass or basalt rovings) were impregnated with an epoxy resin to form meshes. The physical and mechanical properties of the flax based meshes were assessed and the alkaline resistance of these reinforcing materials was evaluated to determine their durability in a cementitious matrix. At isoweight of reinforcement, the flax-based meshes demonstrated the best performance in terms of specific modulus and specific strength compared to the hybrid meshes. The hybrid meshes from the control batch displayed specific properties in the same range, whether they were constituted of AR-glass or basalt. However, the use of alkali-resistant glass rovings strongly mitigated the degradation of the mechanical properties of the hybrids meshes by making them less affected by the alkaline environment, among all the reinforcement meshes. In contrast, hybrid meshes with basalt experienced an extensive reduction in tensile strength and strain after exposure to alkaline environment, due to the corrosion of the basalt fibres. Pull-out tests revealed maximum bond strengths for the flax based meshes embedded in a high-performance concrete matrix.