Strength, economic and environmental analysis of marginal embankment soil stabilised with blended Rice Husk Ash-based binders

Stabilisation of marginal road embankment materials available in the vicinity of the construction sites can mitigate the expenses and energy consumption associated with transporting high-quality embankment materials. This research investigates the effectiveness of different rice husk ash (RHA)-blended binders in treating marginal embankment material in terms of strength, cost, and emission characteristics. Four RHA-blended binders were used to treat marginal soil: RHA with fly ash (MS-RHA-FA), RHA with Lime (MS-RHA-L), RHA with ordinary Portland cement (MS-RHA-OPC), and RHA-FA based geopolymers (MS-RHA-FA-GP). Tests including modified Proctor compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) were conducted. Subsequently, utility analysis was conducted including UCS, CBR, cost and emission as the key factors. The results revealed that MS-RHA-OPC met the specifications for a Type I embankment material, suitable for constructing homogeneous embankments up to 10 metres in height. Meanwhile, all other binders satisfied the requirements for type II embankment materials, which can be used as fill materials for zoned embankments according to Institute of Construction Training and Development (ICTAD) specifications. The utility analysis revealed that MS-RHA-OPC is the best binder in terms of strength, cost, and emission. Overall, RHA-blended binders can be successfully used to stabilise marginal embankment material.