The study investigates the impact of aggregate gradation on Dense Bituminous Macadam (DBM) mix properties, which are essential for the performance of flexible pavements. By analysing existing pavement structures and mix designs, the study identifies how different aggregate sizes and distributions affect overall performance and longevity, particularly under various traffic and environmental conditions. Despite extensive research, gaps remain in understanding optimal aggregate gradation, especially for high-traffic and extreme weather scenarios. Current specifications may address these challenges, potentially leading to premature pavement failures such as rutting and cracking. Key tests, including Indirect Tensile Strength (ITS) and fatigue testing, were employed to evaluate the mix properties. The Optimum Binder Content (OBC) was determined for various DBM grades: 4.5% for both DBM Proposed Grade I and II, and 5% for both DBM MORTH Grade I and II. The results show that the proposed DBM gradations outperform the current MORTH standards. DBM Proposed Grade I, with an OBC of 5%, demonstrated the highest ITS with a 93.02% Tensile Strength Ratio (TSR), indicating superior moisture resistance. DBM Proposed Grade II also showed better performance in moisture resistance and overall durability under repeated loading conditions. Notably, the proposed gradations led to a 16.63% and 18.96% increase in fatigue resistance compared to MORTH grades, suggesting enhanced durability and longer service life. These findings underscore the potential of the proposed gradations to significantly enhance pavement performance and extend service life beyond current standards.