Geopolymerization of Mine Tailings for Pavement Applications: Properties, Limitations and Future Directions

Abstract

Abstract Pavement construction relies heavily on natural aggregates and conventional stabilizers such as Portland cement (PC) and lime, contributing to resource depletion, high energy demand, and significant greenhouse gas emissions. Geopolymerization, the alkaline activation of aluminosilicate materials, offers a more sustainable alternative. Mine tailings (MT), abundant mining by-products rich in silica and alumina, are attractive geopolymer precursors, although their reuse is constrained by variable composition and potential toxicity. In mining-intensive countries like South Africa, copper, cassiterite, and gold MT represent promising resources. This review critically synthesizes current knowledge on the physicochemical properties, mechanical performance, and environmental implications of geopolymerized MT in pavement applications. Unlike previous reviews that consider MT or geopolymers in isolation, it establishes a pavement-engineering–driven framework linking MT characteristics, geopolymer chemistry, and pavement performance requirements across laboratory, environmental, and field scales. The reviewed evidence indicates that MT-based geopolymers can achieve higher strength and superior durability than PC or lime-stabilized bases while reducing CO 2 emissions by up to 80% through clinker substitution and waste valorization. However, challenges including heterogeneous mineralogy, high activator costs, and limited field validation continue to hinder widespread adoption. As such, future opportunities lie in developing low-cost or waste-based activators, standardized mix design and performance protocols, and systematic pilot trials to bridge the laboratory–field gap. Emerging applications, such as hybrid stabilization and sensor-embedded smart pavements, further underscore the potential of geopolymerized MT to transition from limited, experimental use toward broader adoption in low-carbon pavement infrastructure.