Résumé
Nowadays, the construction field is responsible for a quarter of French emissions of greenhouse gases. In order to minimize this impact, one solution is to promote the use of local and biobased materials with a low carbon impact. Biobased resources can be mixed with a binder to produce light (150 – 500 kg.m⁻³), medium (500 – 1200 kg.m⁻³), or high density (1200 – 1800 kg.m⁻³) biobased concretes. The fire behaviour of these materials is still poorly documented. In this work, combustion microcalorimetry tests were conducted to measure the amount of energy released during the combustion of various bioresources while bomb calorimeter tests allowed quantifying their gross heat of combustion. Cone calorimeter experiments were performed to study the ignition of biobased concretes. Results provide general knowledge and data regarding the fire behaviour of bioconcretes. It was observed that only the lightest ones ignite. It appears that ignition relies on two parameters: the combustion energy density of bioconcrete and the energy required to heat the material to the ignition temperature. One criterion is proposed to predict ignition. It accounts for different endothermic processes, such as the bioresource pyrolysis, the possible decomposition of the binder and the heating phenomenon itself up to the pyrolysis temperature.