Preparation and performance of energy-saving and environment-friendly autoclaved aerated concrete prepared by quartz tailings sand

In order to realize the resource utilization of solid waste, autoclaved aerated concrete (ACC) was prepared by hydrothermal synthesis with quartz tailing sand (QTS) as the main siliceous material. The effects of fineness and content of QTS on the properties, hydration products and microstruc-tures of AAC were investigated by particle size analysis, physical and mechanical properties test, X-ray diffraction analysis (XRD), fourier trans-form infrared spectoscopy (FT-IR), and scanning electron microscope (SEM). The results show that the AAC containing 65% QTS (in mass per-centage) with a specific surface area (SSA) of 320 m2 kg-1 can achieve a compressive strength of 4.43 MPa and bulk density of 560 kg m-3, which qualifies the requirements of B06, A3.5 of AAC sample regulated by the composition and morphology GB/T 11969-2008. The small size of QTS particles and the high thickness of the slurry are harmful to form a good pore structure of AAC. When the blending percentage of QTS is too high, the unreacted QTS particle increase and accumulate within the system, which reduces the space among them and thus influences the growth and crystallization of hydration products and the properties of AAC. Phase analyses show that the main crystalline phases in the AAC samples are to-bermorite, C-S-H, calcite, residual quartz and residual minerals from QTS. © 2019 Ecole Polytechnique de Montreal. All rights reserved.