Flax TRM composite systems for strengthening of masonry: from the material identification to the structural behaviour

Textile Reinforced Mortar (TRM) composites represents nowadays an innovative and efficient technique for strengthening of masonry structural elements. In recent years, the use of plant fibres within the composite, instead of high strength synthetic fibres, emerged as a smart solution to increase the sustainability of such reinforcement system. However, several issues are still open concerning the use of such fibres in inorganic matrices, and the studies in the literature addressing this aspect, although showing a great potential of these systems, are not enough to widely promote such innovative and sustainable technique of reinforcement. With the aim of raising the awareness in the use of plant fibres based TRMs, this study proposes a comprehensive mechanical characterisation of a Flax TRM system conceived as reinforcement of masonry elements. Prior to address the issue of the composite characterisation, its components, i.e. textile and mortar, were physically and mechanically characterised. Then, tensile tests on the composite and shear bond tests on Flax-TRM-to-masonry substrate elements were carried out to qualify the composite material and its adherence behaviour with a brick-masonry element. Consequently, on a structural scale, the contribution of the reinforcement system on the shear capacity of masonry elements was analysed by means of diagonal compression tests. Finally, innovative solutions to improve the mechanical performance of the studied reinforcement system were proposed and their efficiency was discussed. The study confirms the potential in the use of plant fibre textiles as reinforcement in TRM systems, outlines the aspects on which it is necessary to act to increase their efficiency, and shows some technical solutions to improve it. [edited by Author]