Study on the structure and properties of autoclaved aerated concrete produced with the stone-sawing mud

The mineral composition of the stone-sawing mud is mainly quartz, containing a small amount of sodium feldspar and potassium feldspar. It could be instead of river sand to be used for preparation of the autoclaved aerated concrete (AAC). The results showed that under the same condition, the porosity rate of the AAC with stone sawing mud and river sand was 73.3% and 74.6% respectively. The average pore size was 0.82 mm and 0.95 mm respectively. The AAC prepared with stone sawing mud and river sand have good thermal insulation performance with the thermal conductivity of 0.14 W/(m·K). As the amount of stone sawing mud replacing the river sand increased gradually, the bulk density and the compressive strength of the AAC were gradually increased. The X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that the amount of hydrated products of the tobermorite and the calcium silicate hydrates (C-S-H) in the AAC with stone-sawing mud were more than that in the AAC with the river sand. The crystallization of tobermorite crystals in the AAC with the stone-sawing mud grew into a leaf shape, and interleaved with each other to form a dense structure net, which made the AAC with improved mechanical properties.