Refractories are heterogeneous materials designed to operate in harsh working environments which sometimes lead to their premature failure. Therefore, it is necessary to enhance their properties to ensure consistent furnace performance and operator safety. Among these properties, the thermal shock resistance of refractories is a parameter of significant interest which is known to be closely related to their mechanical behaviour. In fact, an existing network of micro-cracks within the microstructure of refractories often leads to non-linear phenomena around the crack tip which are beneficial for their crack propagation resistance and thus, their thermal shock resistance.

In this work, refractory materials with a non-linear mechanical behaviour were chosen in order to highlight their fracture behaviour. Experimental tests are today commonly analysed with the help of DIC method which allows to easily provide the displacement field and, then, the strain field after post processing. Nevertheless, for application to fracture analyse, the data obtained by classical DIC can lead to some drawbacks since the assumptions of flow continuity and homogenous material transformation could be not strictly respected locally. In fact, in such case, several errors can appear in the vicinity of the crack. Therefore, the aim of this paper is to present a new DIC technique which has been specifically adapted to the studies of local discontinuities in refractories. In this purpose, this new DIC method, called 2-Parts DIC (2P-DIC) has been improved to take into account the potential local occurrence of such discontinuity. The material transformation, usually assumed homogeneous inside each subset for classical DIC, is thus here more complex and a discontinuity of displacement should be taken into account. Thus, each subset which is crossed by a crack can be cut in two parts with different kinematics. By this way, it is possible to automatically find the fracture paths and follow the cracks geometries (length, opening). Performances of this new procedure will be discussed in this paper and experimental tests commonly applied to refractories (Wedge splitting test, Brazilian test or bending) will be presented.