High-efficiency mix design for molybdenum tailings autoclaved aerated concrete: A statistical and multiscale investigation of proportions and microstructure.

Abstract

Autoclaved aerated concrete (AAC) is valued for its lightweight, insulating, and load-bearing capabilities, yet high-efficiency optimizing density and strength remains challenging. Efficient design of tailings-based AAC now requires considering synergistic effects among multiple variables, as single-variable control has become inadequate. To address this gap, this study systematically investigates the synergy among lime-cement ratio (LCr), calcium-silica ratio (CSr), and water-solid ratio (Wr) in AAC produced with molybdenum tailings as the primary siliceous resource. Single- and two-factor ANOVA combined with principal component analysis revealed that adjusting these parameters significantly influences dry density, compressive strength, and gas-release kinetics. Characterization analyses further confirmed that fostering well-crystallized tobermorite while limiting low-crystallinity carbonates is crucial to improving porosity and strength. Results indicate that an appropriate Wr effects slurry fluidity, yielding balanced density and strength. Meanwhile, excessive lime content prolongs foaming time, leading to increased C-S-H and disordered carbonates, which undermine mechanical performance. Overall, this integrated approach provides a data-driven pathway to high-performance AAC from molybdenum tailings, optimizing density-strength trade-offs with minimal resource consumption.