Study on Preparation and Performance of Aerated Concrete Using Spodumene Mining Residue as Silicious Material

In this research, the spodumene mining residue was used as siliceous material, completely replacing quartz sand, to prepare aerated concrete. The mechanical properties, pore structure, hydration characteristics of the aerated concrete, and the spodumene mining residue–cement paste interaction mechanism were studied by orthogonal experiment, X-ray diffraction, Fourier-Transform Infrared Spectroscopy, thermogravimetry, and mercury-injection test methods. The result showed that the water–cement ratio significantly affected the mechanical properties and dry density of the aerated concrete. The content of aluminum powder paste, spodumene mining residue, and water-cement ratio significantly affected the pore structure of aerated concrete. The pore size was mainly distributed in the range of less than 100 nm in hardened samples. The main hydration products of the aerated concrete containing spodumene mining residue were xonotlite, tobermolite, and C-S-H gel (or its derivatives). Spodumene mining residue had a small amount of active silicon and aluminum components, which could be motivated by an alkaline environment. In the simulation pore solution, the weak pozzolanic reaction was produced to generate C-S-H and its derivatives, which adhered to the surface of the spodumene mining-residue particle and filled in the interface between spodumene mining residue and cement paste, to improve the density of aerated concrete.