A Abstract Green concrete, ecologically friendly concrete, and energy saving are key features of the modern era. Among the components of concrete, cement is the primary element and the one that contributes most to air pollution. One of the alternatives that is in demand due to the production process is slag cement, also known as ground granulated blast furnace slag (GGBFS), which is produced by processing waste from the steel industry and is more costeffective than Portland cement (PC). While preserving the benefits of concrete's mechanical qualities, this substance with cementitious qualities may be able to partially replace the cement in the mixture. Test items created with a slag cement substitution content of 0%, 10%, 20%, 30%, 40%, and 50% of the weight of the needed cement and aged for 28 days were used in this laboratory study. Concrete having a compressive strength of f'c = 38 MPa was designed as the control test object. According to the reference, the slag cement utilized has an activity index grade of 80. Through measurements of the concrete's modulus of elasticity (E), compressive strength (f'c), and stress-strain relationship (f), the investigation was carried out to ascertain the effectiveness of slag cement in concrete. Due to a slower chemical reaction than PC, the test revealed that replacing slag in concrete reduced its compressive strength, strain, and modulus of elasticity at 28 days.