The effect of sintering temperature and applied load on the microstructure and physical properties of local bricks

The objective of this research work is to investigate the effects of sintering temperature and applied load on the properties of local bricks from Biskra (Algeria). A clay–sand composite (70% clay and 30% sand) was compacted under loads of 4 and 6 tonnes, then sintered at 750 °C, 850 °C, 900 °C, 1000°C, and 1200°C for 2 hours. The main characterisation techniques used for the raw composite of clay and sand were X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) For the sintered samples the XRD, FTIR and optical microscopy were used, followed by different tests of apparent porosity, water absorption and apparent density. and optical microscopy. The apparent porosity and water absorption decreased to 4.53% and 2.3%, respectively, with increasing sintering temperature up to 1000 °C, while the apparent density increased to 1.64 g/cm3. The best physical properties were achieved after sintering at 1000°C under a 6-tonne load. However, samples sintered at 1200 °C were burned. These transformations were accompanied by the growth of certain phases, such as quartz, and the disappearance of others, such as calcite and montmorillonite.