Effect of thermal treatment on damage mechanical behaviour of refractory castables: Comparison between bauxite and andalusite aggregates

During service life, refractory castables are subjected to different solicitations. The knowledge of their damage behaviour under such solicitations is highly needed for a better understanding of mechanisms, which induce the final rupture of structures made with refractories. Since these materials are often used as walls of metallurgical tools, thermal gradients in such structure can lead to severe mechanical stresses in the outer layer of the refractory part which is at a rather low temperature.This study deals with the mechanical properties at room temperature (by tensile test) of two refractory castables treated at different temperatures (110 °C, 250 °C, 500 °C, 700 °C, 900 °C and 1100 °C) in order to reproduce the thermal gradient in walls of metallurgical tools. Two refractory castables are considered: an ultra-low cement content bauxite-based material (Bau-ULCC) and a low cement content andalusite-based material (And-LCC).