Macro- and Microstructural behaviour of Lime-stabilised marine soil treated with Nano-titanium dioxide

Weak soils in marine environments present unique challenges for engineering endeavours due to its inherent characteristics and the dynamic nature of aquatic systems. In recent times, the use of nanomaterials has emerged as an effective method for strengthening such soft soils. The present study highlights the effect of nano-titanium dioxide on the strength, plasticity, and compressibility characteristics of marine soil treated with the optimal amount of lime (5%). The potential of nanoparticle in modifying the geotechnical behaviour was examined by adding 0.5%, 0.7%, 1%, and 1.2% of N-TiO₂ per unit weight of dry soil. The unconfined compressive strength values of untreated, optimally lime-treated and optimally nano-treated soil specimens were 47 kPa, 467 kPa and 164 kPa, respectively. After 28 days curing period, the unconfined compressive strength of optimally lime-treated marine soil samples mixed with the optimal amount of 0.7% N-TiO₂ showed a nine-fold increase to 491 kPa with respect to untreated soil. After the nanotreatment, the liquid limit reduced by 51% and the plasticity index lowered by 74%. This resulted in the improvement of the coefficient of consolidation from 0.001 to 0.004 cm²/s and a reduction in compression index value from 0.39 to 0.17. The microstructure of soil samples was examined using various techniques such as X-ray powder diffraction analysis, Field Emission Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, and Brunauer–Emmett–Teller surface area analysis. The experimental observations indicate that marine soil treatment using N-TiO₂ is a promising technique to improve the geotechnical behaviour of marine soil.