Shear strengthening of masonry walls with Flax Textile Reinforced Mortar composite systems

Masonry constructions built in the past decades in earthquake-prone areas are generally characterised by significant levels of seismic vulnerability. Therefore, strengthening and retrofitting of those constructions is more and more perceived as a major societal challenge, also in the light of damages and casualties induced by recent seismic events, such as those occurred in central Italy. Several techniques are nowadays available for enhancing seismic safety of existing masonry structures. Among them, the use of composite materials is widely accepted as one of the most convenient options. Besides the first generation of composites materials, based on polymeric matrix, a new type of materials adopting an inorganic matrix is attracting a growing interest within the scientific and technical community: these materials are often referred to as Textile Reinforced Mortars (TRM). This paper reportsthe results of a series of tests carried out with the aim to investigate the potential of a novel type of TRM in enhancing the in-plane shear capacity of masonry walls. Specifically, the TRM system under consideration is based on adopting a flax fabric as internal reinforcement. Therefore, it is characterised by high sustainability properties and a mechanical behaviour that has been investigated within a companion paper. The experimental activity confirms the potential in the use of plants fibres based composite systems as reinforcement of masonry elements. In comparison with unreinforced walls tested as reference, the peak load doubled. Moreover, the use of Flax-TRM led to a ductile behaviour never shown in unreinforced walls typically characterised by a brittle response. The research study paves the way for further investigation aimed at both identifying the performance under different load configuration and improving the composite material response.