Investigation of using Aspergillus Oryzae Fungi and Soybean Flour for increasing shear strength durability of sand

This research examines the possibilities of utilizing fungi, namely Aspergillus Oryzae , to increase sand's shear strength and durability. The experiments were conducted in a laboratory, where the samples were prepared as ideal cylindrical specimens for testing using the Unconfined Compression Test. Some factors that can improve the shear strength of the treated sample are being investigated, including inoculum dose, incubation method, incubation period, and supplementary nutrition (soybean flour or rice flour). The unconfined compressive strength test determines the shear strength of treated materials. Key results demonstrate that the outside incubation method yields better growth of fungi and produces higher shear strength. 10% or 15% of water content is suggested for the sample to be prepared. At 5% water content, the Fungi could not grow properly. Meanwhile, 10% to 15% water content yields close shear strength of treated soil during the 28-day curing period, which is about 160 kPa. Moreover, additional soybean flour has a better effect than additional rice flour in the outside incubation method. Finally, soil treated with Aspergillus Oryzae has a lower shear strength than soil treated with Rhizopus Oligosporus and Rhizopus Oryzae when soybean flour is added. With the 10% inoculum dosage, 5% soybean flour dosage, and 10% water content, the shear strength of Aspergillus Oryzae Sp. Fungi-treated soil could have about 20% lower shear strength than Rhizopus Oligosporus and Rhizopus Oryzae- treated soil. Moreover, when soybean flour is omitted, soil treated with Aspergillus oryzae performs better than soil treated with Rhizopus oligosporus and Rhizopus oryzae. This highlights Aspergillus oryzae's potential as a more effective alternative for soil stabilization. These findings provide valuable insights into optimizing fungal-based soil improvement strategies, supporting the advancement of sustainable and eco-friendly geotechnical solutions while reducing reliance on conventional chemical stabilizers.