Numerical analysis of residual tensile properties and strain rate sensitivity of textile reinforced mortar interface behavior after thermal exposure

Abstract This study presents a comprehensive finite element (FE) investigation of Textile-Reinforced Mortar (TRM) composites subjected to uniaxial tensile loading at temperatures of 20, 200, and 400 °C. A detailed micro-modeling approach with cohesive zone models was implemented to characterize the complex interface mechanics between textile reinforcement and mortar matrix. The numerical models were rigorously validated against experimental data from tensile tests and Digital Image Correlation (DIC) measurements, demonstrating excellent agreement with deviations below 7%. The research identified critical interface parameters governing TRM behavior, including normal and tangential stiffness components, strength limits, and damage evolution characteristics across different temperature regimes. Results revealed distinct temperature-dependent transitions in failure mechanisms, shifting from predominantly shear-dominated behavior at ambient temperature to slip-dominated responses at elevated temperatures. A notable finding was the enhanced mechanical performance at 200 °C, attributed to improved fiber-matrix interface properties, followed by severe degradation at 400 °C. Parametric sensitivity analyses identified key relationships between interface parameters and mechanical response, with a critical threshold temperature at 200 °C where interface properties showed heightened sensitivity to parameter variations. Extended numerical simulations indicated potential loading-rate dependency, particularly pronounced at elevated temperatures. This work provides essential insights into the thermal degradation mechanisms of TRM systems and establishes a robust numerical framework for predicting their residual performance after thermal exposure, providing a foundational framework for multi-hazard assessment.