Exploring the Potential of Landfill Mined Soil-Like Fraction for the Development of Sustainable Controlled Low Strength Material
Authors :- PH Dalal, M Patil, KKR Iyer
Publication :- Indian Geotechnical Journal, Springer, 2025
Controlled low strength material (CLSM) has been successfully utilized in recent years as an alternative to backfill and structural fill, for pipe and conduit bedding, and as improved subgrade material in infrastructure projects. Efforts have been made to develop sustainable CLSM by several researchers through utilization of different waste materials. In this context, the present study explores the potential of novel landfill mined soil-like fraction (LMSF) as a filler material for the development of sustainable CLSM. The different proportions of LMSF and fly ash have been explored as partial replacement of sand (filler) and cement (binder) in CLSM, respectively. The performance of CLSM mix and specimens are studied through flowability test, hardening time test, unconfined compressive strength test, unconsolidated undrained triaxial test, and microstructural studies (viz., FTIR, XRD, and SEM). The study findings reveal that utilization of LMSF yields CLSM with average unconfined compressive strength in the range of 350–900 kPa. Further, the peak strength, strain corresponding to peak strength, and the post-peak residual strength increases for CLSM under confinement. The microstructural details reveal CaCO3 and C-H formation with well-cemented microstructure. The study also observes that addition of nominal proportion of fibres (0.05%) enhances the strain energy density by 277% as compared to CLSM without fibres, while also yielding substantial improvement in the post-peak residual strength. Removability modulus and sustainability coefficient have also been evaluated for CLSM combinations to confirm its ease of excavation and sustainability, a small step towards achieving United Nations sustainable development goals.