From curing to fire accident: a novel, comprehensive model for concrete’s fire resistance

The durability of concrete under extreme temperatures is primarily influenced by the behavior of calcium silicate hydrates (C-S-H), the primary binding phase in the material.During heating, the release of chemically bound water within C-S-H leads to degradation of material properties, ultimately contributing to spalling.To accurately predict concrete's performance in fire scenarios, comprehensive thermo-hydro-chemical (THC) models are indispensable.This research presents a novel THC model that simulates the entire lifecycle of concrete, from its initial casting to potential fire accidents.The model comprehensively accounts for the interplay between temperature, humidity, and the chemical reactions taking place within the concrete microstructure.By incorporating the effects of C-S-H hydration and dehydration, the model provides a more accurate representation of concrete's behavior under various conditions.A key innovation in this work is the development of a novel adsorption-desorption model that captures the irreversible nature of chemical damage within the porous structure.This model simplifies the calibration process, requiring fewer experimental inputs.The model is validated against experimental data, demonstrating its ability to accurately predict concrete's response in both early-age behavior and high-temperature conditions.The results underscore the significant impact of the initial hygral state on the concrete's fire resistance, highlighting the importance of considering this factor in structural design and analysis, especially in real-world conditions, where the heterogeneity is high both in the water distribution and, consequentially, in the resulting microstructure.Finally, another novelty of the current work is the availability of the developed thermo-hydro-chemical code made publicly available on GitHub, facilitating its application and further research in the field of concrete fire safety.