Enhancing the Strength of Geopolymer Composites Synthesized from Iron Ore Tailings and Fly Ash for Use as Subgrade Material in Pavement Construction
Fly ash; Geopolymer; Iron ore tailing; Leachate; Pavement design; Subgrade material; Waste management
As the idea of sustainable pavement becomes more important, an increasing number of industrial waste products and recycled materials are being used in the pavement industry to conserve natural resources. This study evaluates the potential use of iron ore tailings (IOT) blended with fly ash (FA) and activated with NaOHNa?SiO? solutions as a liquid alkaline activator (L) to synthesise IOT-FA geopolymers, which can be used as a sustainable material for the pavement subgrade layer. The influence of FA replacement levels and alkaline activator ratios on the geotechnical and microstructural behaviour of IOT was examined through compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests, supported by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses. The results show that 20% FA replacement gives the optimal mix, resulting in a 28-day UCS improvement of over four times that of untreated IOT due to enhanced geopolymerization. The liquid alkaline-activated mixes achieved CBR values of ? 8, meeting IRC requirements for subgrade applications. SEM analysis revealed dense gel formation and improved particle bonding, while XRD results indicate the development of geopolymeric reaction products. TCLP results indicate that metal leaching remained within permissible limits, establishing the environmental safety of the developed composite. The thickness of the pavement layer was designed using IITPAVE software based on CBR values and assessed against IRC:372018 criteria. The analysis indicated a reduction in layer thickness for various daily commercial vehicle counts ie, CVPD (450,1000), across all evaluated combinations. Overall, the study demonstrates that alkaline-activated IOTFA mixtures offer a technically viable and sustainable alternative for pavement subgrade construction. Chinese Society of Pavement Engineering 2026.
International Journal of Pavement Research and Technology;
Restricted Access; Hardcopy may be available in the library
https://doi.org/10.1007/s42947-026-00738-1 https://www.scopus.com/pages/publications/105034675348?origin=resultslist
Anju M.J., Christ (Deemed to Be University), Bangalore, India; Beulah M., Christ (Deemed to Be University), Bangalore, India; Varghese A., Jyothi Engineering College, Thrissur, Cheruthuruthy, India