This document compares the compressive strength of concrete using Ground Granulated Blast-furnace Slag (GGBS) as a substitute for Ordinary Portland Cement through accelerated curing methods. It examines various percentages of GGBS replacement (10%, 20%, and 30%) in M20 and M30 concrete mixes and evaluates their strengths under different curing conditions (normal, warm water, and boiling water). The findings indicate that GGBS can enhance the durability and compressive strength of concrete, particularly at lower replacement levels, and highlight the effectiveness of various curing techniques.