Environmental pressure, high cost and shortage of natural aggregates creates the situation, to investigate the similar type of materials for geotechnical application. Limited use of copper slag has created huge heap of waste dump and large dump of slags not only requires plenty of land, but also wastes resources and can potentially have an impact on the environment. In this experimental study, large direct shear tests were conducted to obtaining the coefficient of interaction of two types of geogrid with copper slag and sand. A large size shear box of length 300 mm, width 300 mm and height 200 mm is used. The shear strength parameters of copper slag and sand were tested in large direct shear apparatus with and without geogrid. The performance of copper slag has compared to the sand. Biaxial geogrid made of pol-ypropylene and triaxial geogrid made of bamboo strips were used. Based on the test results, the coefficient of interaction varies from 0.81 to 0.90 for polypropylene biaxial geogrid and 0.67 to 0.81 for bamboo tri-axial geogrid. The unreinforced and geogrid reinforced copper slag was found to meet the shear strength criteria required for construction material in geotechnical applications.