Study on Mechanical Properties of Gold Mine Tailings Stabilized by Composite Alkali‐Activated Materials

Gold mine tailings (GMTs) pose significant environmental challenges, and while alkali‐activated materials (AAMs) have been widely used as sustainable alternatives to Portland cement for stabilizing geotechnical materials, further research is needed to optimize their composition and performance, particularly by incorporating traditional industrial waste residues to develop composite alkali‐activated materials (CAAMs) with improved mechanical properties and reduced environmental impact. Different CAAMs admixtures (i.e., 0%, 3%, 5%, and 8%) and gold mine tailings were prepared, and the samples were solidified under saturated water and no air. In order to investigate the mechanical characteristics of CAAMs‐stabilized GMTs, laboratory direct shear tests were carried out on samples after curing them for 3, 7, 14, and 28 days, respectively. The test results showed that with the extension of curing time, the brittleness of the samples increased, and the stress–displacement curves for all the cured specimens changed from plateau type to peak type. Both curing time and CAAMs content are conducive to improving the shear strength of CAAMs‐stabilized GMTs samples, but the increase rate decreased as the vertical confining stress increased. Furthermore, the influence of CAAMs content on shear strength increment was larger than that of curing periods. The exponential growth model could well describe the change of shear strength with the curing periods under different vertical stresses. The paper can provide theoretical support for the application of CAAMs to enhance the stability of tailings dams.