A radiation dose above the maximum permissible limit is harmful to our environment and our bodies. Study of radiation absorption in material has become an important subject to protect living creature and environment from harmful effect of radiation. Thus it is desirable to have the knowledge about the effective materials for neutron and gamma ray shielding. Concrete is the most widely used construction material in the world for this purpose. The aggregate of concrete plays an essential role in modifying concrete properties and physical-mechanical properties of concrete affect significantly shielding properties of concrete. This paper summarizes the results of investigation carried out on the concrete containing colemanite at different ratios. The intent of this research was to investigate the effect of the colemanite on physical and mechanical properties of concrete using colemanite as replacement aggregate. Slump, air content, compressive strength, split tensile strength, Schmidt hardness, modulus of elasticity, freeze-thaw durability, unit weight and pulse velocity were physical and mechanical properties investigated. It was observed that increasing colemanite ratio in volume has affected engineering properties of concrete and colemanite replacement up to 30% can be considered acceptable.