Acoustic emission characteristics of rubber powder modified fiber‐reinforced concrete pre‐ and post‐elevated temperatures

Abstract The incorporation of fibers can effectively mitigate the degradation of static mechanical properties in rubberized concrete and further improve its toughness. However, the internal structural damage evolution and failure mechanisms pre‐ and post‐elevated temperatures remain unclear. Therefore, this study uses acoustic emission (AE) technology to monitor the fracture process of fiber‐reinforced rubberized concrete pre‐ and post‐elevated temperatures in real time, and applies avalanche dynamics theory to statistically analyze the AE signals generated during the loading process. The study discusses the influence of rubber powder (0%, 5%, 10%, 15%) content and ambient temperature (25°C, 100°C, 200°C, 400°C, and 600°C) on the probability distribution of AE characteristic signals and their corresponding distribution indices. Results show that enhancing rubber powder content significantly raises the percentage of low‐energy events in the fracture process, indicating improved ductility. The AE characteristic index also increases with higher rubber powder dosage, reaching ε , τ , and α values of 1.55, 2.35, and 2.80 at 15% rubber powder. Under elevated temperatures, high‐energy events decrease while low‐energy events increase, reducing the monitorable AE signal. The characteristic index increases with rising temperature, with ε , τ , and α being 1.65, 2.62, and 3.80 at 600°C. The avalanche index correlates with peak load variations and is sensitive to microstructure changes.