Influence of cement addition on wetting-drying cycles, compressive strength and tensile strength of high plastic alluvial soil

• Cement addition significantly improves wet-dry cycle and tensile strength of HPA soil. • After 28 days, at 7% cement, 9 fold increase in UCS was noticed. • After 28 days, wet-dry cycle with 7% cement resulting in loss of UCS by 13.89%. • After 28 days, at 7% cement, 8.5 fold increase in tensile strength was noticed. • 10 days soaked CBR was found to be 18.68% higher than 4 days soaked CBR at 7% cement. • Significant improvement in volumetric shrinkage was noticed at 7% of cement. High plastic alluvial soils severely affect the performance and stability of civil engineering structures, such as road subgrade, foundations, dam, and embankment, during seasonal variations. This paper presents a comprehensive study on pH, Atterberg’s limit, compaction behavior [Maximum dry density (MDD) and Optimum Moisture Content (OMC)], strength characteristics [California Bearing Ratio (CBR), Unconfined Compression Strength (UCS) and Indirect Tensile Strength (ITS)], durability (wetting-drying cycles), elastic modulus (E s ), and volumetric shrinkage characteristics along with microstructural analysis of cement blended High Plastic Alluvial (HPA) soil, at different percentage of cement content (1%, 3%, 5%, 7%) and curing conditions (i.e., moist and submerged). Experimental investigation confirms that CBR increased from 1.7% to 57.8% (on 4 days of soaking) and to 68.6% (on 10 days of soaking); whereas, E s was found to be 147.81 MPa and 155.52 MPa with 3% cement, respectively, which are in the range of effective subgrade’s E s = 133-167 MPa as per IRC: SP-37[1]. UCS and ITS also found to be significantly affected by the addition of cement at different curing period (1, 7, 14, and 28 days). After exposure of 6 th wetting-drying cycles, the treated soil with 7% cement, exhibits a UCS loss of 17.5% and 13.89 % corresponding to 7 days and 28 days curing conditions. A considerable reduction in volumetric shrinkage was noticed at 5% cement content. Moreover, to make an economical subgrade with minimal use of cement (i.e., 5%), other additives such as industrial wastes and fibers can be implemented to fulfill the criterion of 12 th or higher wetting-drying cycles.