Assessment of waste clays in the Qusseir region of east central Egypt for production of lightweight bricks

Abstract Background Egyptian Upper Cretaceous waste clay samples from Yunis Mines, Qusseir vicinity, Eastern Desert, were investigated for their chemical and mineralogical compositions as well as for firing. These investigations were carried out to assess the suitability to use the waste clays for the production of lightweight bricks. X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) techniques were applied for characterizing chemical and mineral compositions of the raw clays. On the other side, densification parameters of the fired samples up to 1100 °C were examined by using Archimedes water-saturation methods and by determining the density and crushing strength of the fired bodies. Results Two types of concrete were prepared using different grain sizes: coarse and a mix of coarse and fine aggregates. Concrete batches were prepared, and the mechanical strength and the bulk density were determined. Mineralogically, the waste samples consist of montmorillonite as the predominant clay mineral, with quartz, calcite, fluorapatite, anhydrite, and pyrite as impurities. Bulk density and apparent porosity of the fired clay sample at 1100 °C were 0.89 g/cm3 and 67.19%, respectively, while the bulk density of the two types of concrete range from 0.76 g/cm3 in coarse type with no fines to 0.90 g/cm3 in the coarse with 20% fine fraction. The crushing strength of both types is 25 kg/cm2 for coarse type and 45 kg/cm2 for coarse and fine types, respectively. Conclusions The results showed that the data provides a useful application of waste clay ramps of ancient Yunis mining tunnels in Qussier area with an additional mean to assess their suitability for the production of lightweight brick concretes to reduce density and their relatively good strength in modern buildings for non-loading building units and to enhance the thermal insulation of buildings