Pond ash as a potential material for sustainable geotechnical applications - a review

Energy-harnessing sources significantly influence a country's infrastructure and economic development. Though nuclear and hydel power sources are used for energy harnessing, thermal sources are still the primary power source in India and contribute to 75% of the demand. Thermal power plants exploit large volumes of coal reserves. The combustion of coal leads to 30%-40% of waste ash residues such as Fly ash and Bottom ash. Though Fly ash finds greater applicability, pond ash poses a severe environmental hazard due to its large occupancy of terrain in ash dykes and lagoons. Many research efforts are underway to utilize pond ash in various structural and geotechnical infrastructure projects; however, there are still limitations and apprehensions about its properties and determination. The present study provides a detailed review of the morphological and chemical properties. Further, the geotechnical attributes of pond ash, including strength characteristics, consolidation parameters, and durability aspects, are critically reviewed for the probable application as fill material for backfill and many other applications. Based on the earlier research on pond ash, it could be comprehended that pond ash has wide property variability and finds compatibility with many other pozzolanic admixtures and, in this way, finds broader applicability in geotechnical projects. The way forwards could be a significant step towards cleaner and greener technology.