This research paper explains in detail how well regular concrete works and how well concrete with fly ash and ground granulated blast furnace slag (GGBS) as a substitute for cement. Through a series of experiments, the objective of the study is to perform an experimental approach that promote the usage of partial replacement-based concrete that can replace the conventional concrete and to promote the sustainable development. a dedicated methodology is developed for the study, focussing on the mechanical and durability properties of the materials with inducing sustainable materials. The methodology study examines at the mechanical properties, durability, and microstructural attributes of the concrete blends. Cement concrete specimens with binder ratios (%) of 0.3, 0.4, and 0.5 were tested for compressive strength, rapid chloride permeability, SEM, and XRD at 28, 56, and 90 days. Fly ash and GGBS were used to partially replace cement at 0% to 70% for all binder ratios by weight of cement. There were optimal replacement percentages for each binder ratio and fly ash and GGBS partially substituted concrete had similar or enhanced mechanical properties to conventional concrete. The novelty of the study is to incorporate microstructure analysis for the same samples that shall enable to analyse the behaviour of the partial replaced materials with conventional concrete. In connection with the results, the study had found lower RCPT values in partial replacement concrete specimens, fly ash and GGBS increased chloride ion resistance. SEM and XRD analyses revealed the concrete mixtures' microstructural properties and phase composition, showing how supplementary cementitious materials refine pore structure and provide durable hydration products. This study shows that fly ash and GGBS can improve concrete performance and reduce impact on environment and applications in construction.