Experimental study of the thermo-mechanical behaviour of alumina-silicate refractory materials based on a mixture of Algerian kaolinitic clays

In the framework of a general study carried out on the thermo-mechanical behaviour of refractory products made from Algerian refractory clays, silica–alumina bricks based on a mixture of halloysite from Djebel Debbagh and kaolin from Tamazert were studied. The materialʹs initial chemical composition and physical properties are reported. Uniaxial compression and three-point bending tests were performed under temperature conditions from room temperature to 1200 °C on representative specimens cut from the bricks. The evolution of the materialʹs resistance in tension and compression as of its modulus of elasticity with testing temperature is reported. The thermal expansion of the material was investigated as were optical and SEM micrographs at various temperatures. The evolution of the material rheological behaviour from quasi-brittle, between room and 900 °C, to viscous at higher temperatures was shown by both bending and compression tests. The general behaviour of the material with increasing temperature was analysed through the various microstructure investigations and the presence of micro-cracking induced by the differential expansions of the multiple phases in presence.