Analytical Interpretation of the Tensile Behaviour of TRM Composites with Natural Fibres

The adoption of Textile Reinforced Mortar (TRM) composite systems is getting increasingly popular, especially for the structural retrofitting of ancient masonry structures.Recently, a particular scientific interest in this field has raised towards the use of vegetable fabrics as a greener strengthening solution. This paper aims to deepen the comprehension of the behaviour of these sustainable composite materials under pure traction. Following this scope, a preliminary experimental study has been conducted on flax-TRM coupons. The results are presented, collected with some other experimental data available in the literature, and then compared with the most relevant literature analytical models currently available for predicting the tensile stress-strain response of classical TRM systems. The comparison shows that the mechanical properties of the mortar highly affect the attainment of the first cracking stress. At the same time, the development of the tensile response is influenced by the number of reinforcing layers, which also determines the stiffness of the system until the peak stress and its ductility. A simplified multilinear approach is finally proposed for better catching the trend of the tensile response exhibited by single-cracked TRM coupons.