Feasibility of Mine Wastes Stabilization for use as Pavement Construction Material

Abstract: Abstract
Roads are one of the most important infrastructural systems for economic development. However, pavement designers are often faced with the problem of constructing pavement on or with soils of insufficient strength to support the wheel loads imposed on them either at construction or during the pavement’s service life. Road construction relies heavily on natural materials, with 90% of aggregates coming from virgin sources or quarries. Developing nations face a shortage of high-quality materials, leading to two costly options: finding new quarries or using stabilizers like Portland cement and lime to enhance lower-grade materials. Although using PC and lime improves the mechanical qualities of low-grade natural construction materials, it is associated with severe environmental consequences. Therefore, alternative aggregate materials and stabilization techniques in pavement construction are highly sought after. To narrow this gap, this study formulated a geopolymer binder using quarry dust (QD) and coal ash (CA) to stabilize goldmine tailings (GTs) for road construction. These samples were subjected to physio-chemical characterization using XRF, particle size analysis, and Atterberg limit test. Sodium hydroxide (NaOH) was used as an alkaline hardener. The XRF results confirmed that GTs, QD, and CA were primarily composed of SiO2 and Al2O3, crucial for the cross-linking process providing strength to geopolymer binder. Porosimeter results revealed all raw materials were mesoporous, indicating high reactivity for a more efficient geopolymerization process. This research showed that stabilized mine wastes are suitable for use as pavement construction material according to the American Association of State Highway and Transportation Officials (AASHTO).