Role of nano silica and nano copolymer as partial replacement of cement for stabilisation of problematic north east India peat

This study investigates the partial replacement of Ordinary Portland Cement (OPC) with nano co-additives to stabilize organic peat soil for subgrade stabilization. Nano Silica (NS) and a Zycobond-Terrasil (Zy-Te) solution were combined with 43-grade OPC (10% NS + 90% OPC and 15% Zy-Te + 85% OPC) to evaluate sustainability and strength. Notable improvement observed in UCS, CBR, Triaxial, Permeability, Resilient modulus, and microstructural test results. Stabilized peat showed up to a tenfold increase in cohesion, ∼2 × reduction in permeability, 18.2%-36.4% improvement in resilient modulus, and ∼10% reduction in permanent strain compared to untreated soil. SEM and EDX analysis indicated the formation of calcium silicate hydrate (CSH) and calcium aluminate hydrate (CAH) products binding the peat matrix. A hypothetical IITPAVE analysis demonstrated that stabilized peat could significantly reduce pavement thickness and cost for increased traffic loading (20 MSA to 50 MSA).