Abstract : In current study, Finite Element Analysis (FEA) using ABAQUS software was performed to evaluate the behaviour of RC (Reinforced Concrete) beams. The current study concentrates on behaviour of beams at elevated temperature. Concrete is an important material used in construction field. In the current study, another alternative material is introduced for preparing concrete. Electric Arc furnace Slag (EAFS) is used for preparing concrete by partially replacing conventional coarse aggregate (CCA). The replacement of CCA using EAFS improves the material property of concrete and also the performance of the modified concrete which gives better results compared with concrete with CCA. The results of numerical study consist of load-deflection and stress-strain relation for both the type of concretes. Final result shows the inelastic non-linear behaviour of concrete. The current analysis mainly concentrates on the beams tested at three temperature levels of normal, 500 and 800°C of both conventional and modified concrete. The comparative study shows that EAFS concrete behaves almost the same as conventional concrete at normal and elevated temperature.