Nanomaterials have recently gained considerable attention in ground improvement, as they have the potential to actively interact with soil particles given their high specific surface area. This has encouraged researchers to explore the potential of nanoparticles in improving soil properties. This paper presents the results of an experimental study on the mechanical and microstructural behavior of soft soils treated with nano-zeolite. A series of direct shear tests (DST) and unconfined compression strength tests (UCS) were performed on soil samples containing different percentages of nano-zeolite (0.2%, 0.4%, 0.6%, 0.8%, and 1% by dry weight of soil). The nano-zeolite-treated samples were cured for 1, 7, and 28 days and subsequently tested. The test results indicated that the addition of nano-zeolite resulted in a considerable improvement in the shear strength of soil samples, and the strength gain was influenced by the curing time as well. The UCS of stabilized samples with 1% nano-zeolite at 7 days and 28 days of curing was 10.2 and 16.7 times of untreated soil, respectively. Besides, there was a reduction in the ductility of soil samples upon increasing the nano-zeolite percentage, leading to a reduction in failure axial strain. Microstructural investigations under FESEM and XRD confirmed the formation of cementitious products responsible for strength improvement.
