Due to global population growth and improving economic conditions, infrastructure development in the form of residential homes and commercial structures is increasing yearly. The rising real estate market draws middle-class buyers to upscale apartments and opulent homes at steep discounts. On the other hand the availability of traditional construction materials are reducing. As a result, the idea of partial replacement is a good substitute. The current effort attempts to substitute periwinkle shells gathered from Chennai, the coastal metropolis, for traditional coarse aggregate. Through the compaction factor, slump cone, and flow tests in the fresh condition and the 14-day and 28-day compression tests, flexure tests, and split tension tests in the hardened state, an effort is made to assess the workability and strength of the partially replaced concrete in the laboratory. In addition to the aforementioned, tests are done on the periwinkle shell's influence value, breaking down value, specific gravity, absorption of water, and particle size distribution in order to evaluate the properties with those of conventional coarse aggregate in order to confirm the effectiveness of the former. A notional percentage is deduced through comparison analysis after partial replacement of periwinkle shells with gravel in various percentages of 0%, 20%, 30%, and 40% is carried out. This study reveals an understanding of the characteristics of building materials mixed with periwinkle shells and helps todetermine the ideal combined mixture percentage which can be recommended as an appropriate replacement construction material in the construction of elegant villas and luxury apartments.