Résumé
In the current context of the transition toward low-carbon buildings, bio-based materials are emerging as key solutions due to their reduced environmental impact, carbon storage capacity, and insulating performance. Among these materials, bio-based concretes, combining a mineral binder with plant-based aggregates such as hemp shives, straw, or other organic fibers, represent a promising pathway for more sustainable building systems. However, the incorporation of plant-based constituents raises important questions regarding fire performance, which remains a critical aspect for their wider implementation. Unlike conventional mineral materials, bio-based materials contain an organic fraction that can undergo thermal degradation and combustion, potentially influencing ignition and fire propagation. A clear and quantitative understanding of these mechanisms is still lacking, limiting the ability to design optimized and fire-safe formulations.This study aims to investigate the fire behavior of these bio-based materials, with a particular focus on their flammability and the thermochemical processes associated with the combustion of organic constituents. An analysis of the energetic potential of organic materials was conducted to evaluate the energy released during combustion and its role in the thermal processes occurring within the material. The influence of composition and density on ignition susceptibility was also investigated. The results show that flammability is primarily governed by the balance between the energy released by the plant-based fraction and the energy required to reach the onset of pyrolysis, including the possible decomposition of the binder.Based on these findings, a predictive approach for ignition assessment is proposed. This approach integrates the main endothermic processes occurring within the material and can be used as a design tool to evaluate fire sensitivity at an early stage. Overall, this study provides essential scientific insights for assessing fire behavior, optimizing the formulation of bio-based concretes, and supporting their integration into low-carbon building systems that balance fire safety with environmental performance.