Cyclic bond behavior and end-of-life bio-recycling of FRP strengthening systems

Fiber-reinforced strengthening systems, whether based on fiber-reinforced polymer (FRP) composites or fabric-reinforced cementitious matrices (FRCM/TRM), are extensively used to improve the load-carrying capacity and ductility of concrete and masonry elements. As part of the SAFER-REBUILT project (“Sustainable Approaches for Earthquake-Resistant Rehabilitation Solutions for the Built Environment”), funded by the University of Bari Aldo Moro, this paper reports preliminary numerical and experimental findings focused on two interconnected goals. First, a finite-element framework is developed and validated to simulate cyclic bond degradation of FRP strengthening systems applied to concrete or masonry samples under repeated load–unload cycles. Second, an eco-efficient recycling strategy is assessed experimentally through a novel bioleaching and anaerobic-digestion process for the recovery and disposal of end-of-life FRP materials detached from their substrates. By coupling predictive bond-deterioration models with sustainable recycling techniques, this study establishes a holistic methodology to guide both the design of FRP retrofits and the environmentally responsible management of their lifecycle.