Stiffness Degradation of Textile-Reinforced Mortar under Unloading-Reloading Tensile Cycles

Textile-reinforced mortar (TRM) has proved to be a valid engineering material for the upgrading and retrofitting of existing masonry and concrete structures subject to seismic actions, because it can be applied in thin layers that can increase load-bearing capacity while providing significant durability. However, characterization activities at the composite scale have mainly focused on the material's monotonic behavior and few studies have so far addressed the material's performance in the presence of cyclic actions. In this work, we set ourselves the goal of investigating the uniaxial tensile behavior of a series of cement-based matrix composites reinforced with alkali-resistant (AR) glass fabrics, also considering the possible inclusion of short dispersed polyvinyl alcohol (PVA) fibers. Quantification of the stiffness degradation accumulated by the composites during unloading-reloading cycles allowed us to evaluate the damage evolution in uniaxial tension through data interpolation, providing analytical formulations that may represent a benchmark for the validation of advanced nonlinear simulations