In this study, it was investigate about the engineering behavior of conventional concrete of grade M25, by replacing the fine aggregate by partially with crushed sea shell. On because of progression in the field of infrastructure, the dearth of construction material becomes upsurge day by day. All the investigator was observe to find the substitute construction materials to meet the demand of construction in world wide. The reason behind is, while continuous utilizing of the natural raw material for construction decline the resource of those materials and further, it leads to affect the routine function of the earth and made drastic change in the life cycle of living beings. Therefore, it is obvious to find out the possible alternative material to suit for all type of construction. In this study, the sea shell was used as a fine aggregate in the method of crushed powder in an apparent proportion such as 10%, 20% and 30% replacing in the place of fine aggregate sand. The compression and split tensile behavior of sea shell aggregate mixed concrete comparatively with plain sand concrete was studied under different curing periods such as 7 days, 14 days and 28 days. It was shows that at 20% replacement of crushed sea shell aggregate provide the compressive strength of 35 N/mm2 at 28 days of curing nearly with the design strength of M25 grade conventional concrete. It was also noticed that, the percentage increase of crushed sea shell decline the strength of concrete as radically. Hence it was acclaimed that, the percentage of crushed sea shell as fixed equal or below 10 % to get a better strength of concrete. © 2021 Elsevier B.V., All rights reserved.