Bond Behavior of Masonry Strengthened with Natural Textile-Reinforced Mortar Systems

Textile Reinforced Mortar (TRM) composites are increasingly employed for the repair and strengthening of masonry structures due to their material compatibility, reversibility, fire resistance, and low environmental impact. Recently, plant-based fibers such as flax, hemp, sisal, and jute have gained attention, promoting the development of Natural Textile Reinforced Mortar (NTRM) systems as sustainable strengthening solutions. Nevertheless, their mechanical behavior is not yet fully understood, as it is influenced by fiber characteristics, textile architecture, and bond mechanisms with the masonry substrate. This study presents the first results of an experimental investigation on flax-based NTRM systems for masonry strengthening. Mechanical behavior was assessed through direct tensile tests on dry textiles and composite specimens, while bond performance was evaluated using single-lap shear tests on strengthened masonry blocks. The experimental results provide useful indications of the structural suitability of these systems, also through comparison with conventional basalt fiber-based composites.