Preparation Of Autoclaved Aerated Concrete By Using Graphite Tailings As An Alternative Silica Source

This research aims to produce autoclaved aerated concrete (AAC) by using graphite tailings as siliceous material. The influences of cement dosage, calcium-silicon mole ratio (Ca/Si), water-solid materials ratio (W/S), and foaming agent content on the compressive strength and bulk density of graphite tailings-autoclaved aerated concrete (GT-AAC) were examined. Moreover, the hydration and microstructure of selected GT-AAC compositions were investigated by employing X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, and 29 Si nuclear magnetic resonance. The results manifested that, except for the cement dosage, water-solid materials ratio, and foaming agent content, the calcium-silicon ratio also plays an important role in the production of GT-AAC. GT-AAC with compressive strength of 5.0 MPa and bulk density 666 kg/m(3) was successfully produced by adopting the appropriate mix proportion obtained herein. Microscopic investigation verified the main hydration products of GT-AAC were tobermorite and C-S-H gel. (C) 2020 Elsevier Ltd. All rights reserved.