High-plasticity silt stabilization: Role of waste stone dust, cement, and curing time

This research investigates the use of waste stone dust, a crushing industries byproduct, in combination with cement to enhance the engineering properties of high-plasticity silt. The investigation focuses on evaluating improvements in soil consistency, compaction characteristics, microstructure, and long-term strength behavior. Results indicate that the addition of waste stone dust significantly improves plasticity and compaction characteristics, while the combination of cement and stone dust enhances shear strength more effectively than either material alone. The unconfined compressive strength of untreated soil, initially 57.3 kPa after one day of curing, increased up to 19.4 times after 90 days with 10 % cement addition, with further improvements observed when stone dust was incorporated. Moreover, non-linear regression analysis reveals that strength improvement follows a sigmoidal relationship with cement content and a logarithmic trend with curing time. Furthermore, insights from Consolidated Undrained Triaxial tests and Scanning Electron Microscopy provide further strengthen the stabilization mechanisms of the treated soil. The triaxial results show that adding 6 % cement in natural soil slightly increases the friction angle from 20° to 22° and increases the cohesion from 28 kPa to 60 kPa. However, further addition of 30 % stone dust and 6 % cement slightly improved friction angle and reduced the cohesion from 60 kPa to 26 kPa, which infers that cement primarily increased cohesion, whereas stone dust increases inter-granular friction. More importantly, this study offers a cost-effective solution to enhance behavior, addresses environmental concerns, and improve infrastructure resilience for high-plastic-silt-related problems.