Stabilization of Soft Clay Using Perlite Geopolymer Activated by Sodium Hydroxide

This research presents a study of soft clay improvement using perlite geopolymer (PG) activated by sodium hydroxide. The geotechnical properties of soft clay stabilized with a mixing ratio of PG were investigated, including unconfined compressive strength (UCS) and indirect tensile strength, ultrasonic pulse, and scanning electron microscope (SEM). The mixing ratio, curing time, and curing temperature were well controlled during sample preparation. PG was prepared by mixing six molars of sodium hydroxide solution with perlite at a ratio of 0.95. Soft clay was stabilized by mixing with PG at 10, 20, 30, 40, and 50% by the dry weight of the soil. The samples were cured under 25 and 70 °C for 7, 14, and 28 days. The experimental results show that PG is effective in increasing the strength of stabilized soil. When considering the strength according to the Department of Highways Thailand requirements, it was found that clay: PG 60:40 and 50:50 samples cured at 7 days at 70 °C could be used as a subbase material. The test result confirms that the PG stabilized soil exhibits a denser and stronger microstructure, improving the mechanical properties of stabilized soil.