Modelling of heat transfer through permanent formwork panels exposed to high temperatures

A small-scale fire test was performed on a wood-cement panel intended as a permanent formwork. The tested panel was subjected on one side to a uniform heat flux of about 6 kW/m2. Measurements of the temperature profiles were recorded with thermocouples embedded in the sample. The density and its variation with temperature were obtained by taking weight measurements. The thermal conductivity of the wood-cement composite at room temperature was determined using the hot plate method. Its variation with temperature and that of the specific heat were determined using analytical and numerical approaches. Using the obtained data, a pyrolysis model, implemented in Abaqus, was developed to simulate the effect of heat in the panel. The validation of the model is carried out by simulating charring tests. The model provided reasonable predictions for the thickness of the charred layer and the temperatures profiles across the depth of the panel. The model can supplement the testing of small laboratory samples to characterise the fire performance of these panels, and hence help establish their certification for use in sustainable construction.