Abstract
Dry stacking has emerged as a safer alternative to conventional tailings dams for gold tailings (GT) disposal. Despite growing interest in mine tailings stabilization, much research has focused on conventional binders or alkali-activated binders (AABs) using the two-part method. However, studies on one-part AABs for filtered GT in dry stacking applications remain scarce. This study evaluates the unconfined compressive strength (q u ), secant modulus of elasticity (E 50 ), durability, and microstructural characteristics of GT stabilized with a one-part AAB composed of GGBS, sodium hydroxide, and sodium silicate, comparing its performance with ordinary Portland cement (OPC). The AAB-stabilized GT achieved a maximum q u of 9.18 MPa, approximately 33% higher than that of OPC-stabilized GT (6.92 MPa). Rapid strength development was observed, with 93% of the 63-day strength reached after only 7 days of curing (8.55 MPa). The maximum E 50 reached 2051.7 MPa, nearly 1.9 times greater than that obtained with OPC. Statistical analyses identified binder content and degree of compaction as the primary factors controlling strength and stiffness. Regression models and a porosity/binder content index were proposed as a rational methodology for predicting mechanical behavior and supporting binder mix design. The best-performing AAB mixture exhibited lower mass loss of 1.39%, indicating not only high mechanical performance but also excellent durability. Microstructural analyses qualitatively revealed denser matrices and the formation of hybrid C(N)-A-S-H gels in AAB-stabilized GT, explaining its enhanced performance. In contrast, OPC-stabilized GT exhibited more porous matrices containing C-(A)-S-H gels and ettringite. These findings demonstrate the potential of one-part AAB as a high-performance alternative to OPC for the stabilization of GT in dry stacking.