Mechanical Characterisation of Flax and Jute Textile-Reinforced Mortars

Abstract

Natural fibre textiles embedded in inorganic matrices (NTRM) could offer a strengthening solution for unreinforced masonry structures that satisfies both performance and sustainability requirements. However, the limited understanding of their mechanical characteristics hinders their use. This paper investigates the mechanical performance of flax and jute lime-based composites under direct tension and assesses the mechanical contribution of the NTRM constituents through a multi-scale experimental study. Key design parameters for strengthening applications, such as textile geometry, number of TRM layers and TRM overlay thickness are examined in detail. The results show that textile geometry and reinforcement ratio significantly affect the composite performance. When mechanical reinforcement ratios greater than 3% are provided, flax textiles with smaller diameter and twisted yarns, arranged in denser meshes, ensure good composite action. Overall, flax-TRM composites resulted in a ductile behaviour and developed the highest strength (80–200 MPa) and elongation capacity (4–8%), making them a promising retrofitting solution for masonry, where the use of strengthening systems with moderate stiffness and compatibility with the substrate is of primary concern.