Influence of a Mineral Filler on the Fire Behaviour and Mechanical Properties of a Wood Waste Composite Material Stabilized with Expanded Polystyrene

The use of vegetable fibers composites in structures sometimes presents significant fires risks because of their high flammability. This work aims to study the impact of the addition of mineral filler (clay) on the fire behaviour of wood-polystyrene composites and their mechanical properties. Thus, composites containing 25% of expanded polystyrene binder have been produced. On this base material, proportions of clay ranging from 0% to 15% were gradually added. These samples were elaborated by compaction and for some them, submitted to thermoforming after drying. Both kinds of sample were subjected to flame persistence test;flexural strength and compressive strength test were also measured. The results show that composites without mineral filler ignite continuously until the total consumption and when the mineral filler content increases the combustion time decreases. The addition of the mineral filler allows these composites to pass from class M3 of moderately flammable combustible materials to class M2 of hardly flammable materials, according to the M classification of construction and furnishing materials. The measurement of the mechanical properties shows that the strengths increase when the filler content goes from 0% to 10% and then decrease. This leads to set the optimum content of mineral filler around 10%.