Expansive soil is one of the major soil deposits in India and is spread over more than 300,200 km2. To a large extent, it is mainly found in regions having low to medium slopes and poor drainage conditions. For a sustainable construction project, the use of locally available soil is imperative. This research deals with the use of pavement subgrade layers consisting of locally available expansive soil stabilized with naturally derived Bio-Additives which are more economically viable than the stabilizers in the market. Stabilization of soil is required when the available soil is not able to bear the structural load of the structure. Soil Stabilization is basically the modification of soils to enhance their physical properties. The Bio-additives were mixed with Expansive soil in various proportions from 0, 2, 4, and 6% of the stabilizer. The basic physical characteristics like liquid limit, plastic limit, swelling index, plasticity index, specific gravity and compaction properties, unconfined compressive strength, and California Bearing Ratio were evaluated for the stabilized expansive soil specimens and compared with the unstabilized soil specimen. The results of the study indicate that the basic physical properties get modified due to the addition of bio-additives and the required subgrade quality is achieved. The untreated soil subgrade exhibited a UCS of 6.7 kPa, with mineral stabilization at 6% dosage, the UCS was found to be 16.2 kPa. The UCS results indicated an improvement in compressive strength with soil stabilization. The CBR of the natural subgrade was found to be 8% and with the incorporation of Bio-Additives, the CBR of the soil significantly enhanced and increased to 72% at 6% incorporation which indicates the improvement in bearing strength. It was thus concluded that the treating of Expansive soil with Bio-Additives enhances its strength.