Flexural Behavior of Basalt Textile–Reinforced Engineered Cementitious Composite Plates after Exposure to Elevated Temperatures

The present work aims to study the residual flexural behavior of basalt textile–reinforced engineered cementitious composite (ECC) systems after exposure to elevated temperatures. A total of 48 plates were prepared and subjected to temperature conditions at 20°C, 200°C, 400°C, and 600°C for 2 h. Then, the samples were tested under four-point bending. The residual mechanical properties (including flexural strength, deflection, and stiffness) and mass loss were examined. A scanning electron microscope was employed to observe microstructural changes in basalt textile–reinforced ECC samples before and after exposure to high temperatures. The results showed that basalt textile–reinforced ECC samples exhibited excellent flexural properties in terms of load-carrying capacity, deformation, energy dissipation capacity, and damage tolerance at temperatures below 200℃. However, at 400℃ and 600℃, because of the melting of the polyvinyl alcohol fibers and the decomposition of the hydration products, the stiffness and flexural strength decreased significantly, leading to a brittle failure mode. A simplified theoretical model was proposed for estimating the ultimate moment of the basalt textile–reinforced ECC thin plates, and the calculated values showed a good agreement with the experiments.