Refractory castables are utilized in hazardous environments and thus their reliability should be accurately evaluated to avoid incidents. This work aims to measure the fracture energy of a high-alumina refractory with mullite-zirconia aggregates at 600°C. Wedge Splitting Tests were performed on 5 samples with different sintering temperatures. Images were acquired and analyzed via Digital Image Correlation (DIC). Notch Opening Displacements were used to evaluate the fracture energy at room and high tempartures. For the studied material, a 50°C increase in the sintering temperature increased about 30% the fracture energy of the material, which is also higher at 600°C when compared to room temperature measurements.