Investigating the Effect of Cement Bentonite Stabilized Soft Clay on Mechanical Behavior Under Unconsolidated Undrained Triaxial Loading

Soft clay is characterized by low shear strength and high compressibility. Chemical stabilization using cement and bentonite can improve soil index and mechanical properties through modifying hydraulic characteristics and soil structure. This study aims to investigate the effect of cement – bentonite combinations on the shear strength behavior of soft clay and identify the optimum mixture. Experimental investigation are conducted using the unconsolidated undrained (UU) triaxial test to evaluate the mechanical response of stabilized soil under rapid loading. Several mix composition has designed to determine the optimum mixture. A total of 36 soil samples of 20% cement and bentonite content addition varied from 8%, to 12% in 1% increment will be tested under confining pressures of 100, 200, and 300 kPa. The results show that maximum deviator stress increased with confining pressure whereas its relationship with bentonite was non linier. The mixture at 9% bentonite performed the highest maximum deviator stresses at all confining pressures reaching 390, 450, and 573 kPa, respectively. Further increases in bentonite content beyond 9% resulted in lower maximum deviator stress. The failure envelope analysis also indicates that increasing bentonite does not improve shear strength. Through this investigation, 9% bentonite showed the best shear – strength performance among the tested mixture. These findings highlight the importance of optimizing addiyive content to produce better mechanical performance.