In this paper, we present the modelling of the fracture of a refractory ceramic using the fictitious crack model. The parameters of the tension-softening curve of the modelling are obtained, not by numerical fitting of macroscopical data, but after observation of the displacement field around the fracture process zone. The modelling obtained is compared with experimental data and previous modelling made by other authors, giving a good fitting of the experimental values and a modelling at least as good as the one obtained by numerical fitting.