Residual performance of lime, cementitious, and alkali-activated TRM systems after high temperature exposure

Textile Reinforced Mortar (TRM) composite systems have recently been developed using environmentally sustainable binders, including alkali-activated mortars (AAMs). Despite their promising mechanical performance and reduced environmental impact, the feasibility of incorporating AAMs into TRM strengthening systems has not yet been fully established. In particular, the behaviour of AAM-based TRM composites, known as TRAAMs, under elevated temperatures remains poorly understood, and limited experimental evidence is currently available regarding their mechanical stability, bond performance, and failure mechanisms after thermal exposure. This study investigates and compares the performance of TRM systems manufactured with different binders (lime, cement, and alkali-activated) reinforced with coated basalt textiles, both at room temperature (20 °C) and after exposure to elevated temperatures (200 °C, 400 °C, and 600 °C). Residual properties were assessed through mechanical testing and microstructural analyses. Furthermore, the results were benchmarked against data available in the literature for comparable TRM systems subjected to high temperatures. The findings indicate that exposure up to 200 °C has a negligible influence on the TRM residual performance, with TRAAM systems even showing slight improvements. Conversely, exposure to 400 °C and above leads to a significant degradation of performance in all TRM systems.