Investigation of Activated Bauxite-Tailings for Application in 3D Printed Concrete via a Modified Anderson and Anderson-Model (2024-12)¶

This study aims to investigate the application of activated bauxite tailings as supplementary cementitious material (SCM) in 3D printed concrete (3DPC). The modified Anderson and Anderson (MAA) model was applied to optimize the design of the mix ratio of 3DPC to avoid the loss of mechanical properties due to the low reactivity of the tailings. Firstly, the influence of activated tailings on the workability, rheological properties, hydration heat, buildability, mechanical properties and durability of 3DPC was investigated. Subsequently, the microstructure of 3DPC containing various doped tailings was investigated via XRD, thermogravimetric analysis (TGA) and pore structure experiments. The results indicate that the flowability and slump of 3DPC decrease continuously with increasing tailings content, while the plastic viscosity, dynamic yield stress and static yield stress increase significantly. Although incorporating tailings retards the hydration process of 3DPC to some extent, it remarkably improves the buildability of 3DPC. Adding tailings reduces the mechanical properties as well as the resistance to carbonation and drying shrinkage of 3DPC relative to reference group without tailings. Furthermore, 3DPC containing 36% tailings has better mechanical properties than 3DPC containing 24% tailings due to optimized particle gradation. Overall, the MAA model has certain applicability in this study and can provide a new approach for the utilization of bauxite tailings in 3DPC.