Behaviour of clay bricks from small-scale production units after high temperature exposure

The mechanical and thermal behaviour of traditional clay bricks were investigated after one hour exposure at three different temperatures (200, 400, 600 A degrees C). Specimens collected from small-scale production units in Cameroon were used. It has been shown that the mechanical behaviour of traditional clay bricks after exposure depends on their quality of firing, which is most of the time affected by the limits of the traditional technologies used for their production. Among the samples collected, bricks of good quality and low quality of firing were identified. Bricks of good quality of firing have shown a progressive decay of mechanical strength from 200 A degrees C after an increase from the room temperature to 200 A degrees C. Those of low quality have shown an increase in mechanical strength from 400 A degrees C after a stability observed between the room temperature and 400 A degrees C. Both bricks have shown a phenomenon of embrittlement with the increase of the exposure temperature, which was much accentuated in the case of less fired bricks. Thermal conductivity of both bricks has shown a quasi-stability with exposure temperature due to their high porosity from the beginning.