Shear strength is a fundamental property that directly impacts the safety, stability, and performance of various engineering structures and construction projects. The study aims to provide insights into how a commercially available chemical soil modifier Zycobond developed by Zydex Industries influences the direct shear behavior of soil (sandy soil), shedding light on its effectiveness as soil reinforcement agents. As the demand for sustainable and efficient soil stabilization techniques grows, understanding the performance of these specific modifiers becomes essential for informed decision-making in geotechnical engineering applications. The study has focused on soil treated with distinct soil modifiers, along with specific quantities of cement. Shear strength tests are performed using a Direct Shear Test apparatus on the sandy soil of River Kulsi (Kamrup District). The test was carried out on soil samples prepared by adding Zycobond at doses of 0.5–1.5 kg/m3, with increments of 0.25 kg/m3, and cement doses of 1%, 2%, 3%, 4%, and 5% to the original soil sample. The samples were cured for 24 hrs, and a constant density of 1.65 g/cc and a strain rate of 1.25 mm/min was maintained throughout testing. A comparative study of the test findings reveals significant improvements in shear strength for treated samples. The optimal values were recorded at a Zycobond dose of 1.25 kg/m3 and 3% cement, resulting in a 23.2% increase in shear strength and a 28% increase in friction angle. The study shows that the use of cement and Zycobond greatly enhances the shear strength qualities of sandy soil, making it more appropriate for geotechnical applications such as road subgrades.