Concrete has advanced from simple lime mixtures to trailblazing cementitious systems, with innovations such as superplasticizers and fly ash (FA) considerably improving workability and durability in harsh conditions. Though some studies have explored the long-term implications of specialized cements on the durability and service life of structures, research on sulphate resisting Portland Cement (SRPC) remains limited when compared to Portland Slag Cement (PSC). There is a notable research gap regarding the combined influence of FA and SF on the performance and durability of concrete made with PSC and SRPC. This current study investigates the workability and mechanical performance of PSC and SRPC blended with FA and SF, comparing their behavior with Ordinary Portland Cement (OPC53) concrete. The research evaluated workability, compressive strength (7, 28, 56, 91 days(D)), tensile and flexural strengths (7, 28 D), stress–strain response, and UPV (28 D) to analyze concrete behavior. PSC-based concretes demonstrated the highest slump values due to the presence of slag, even with the inclusion of silica fume (SF), whereas SRPC-based concretes exhibited superior workability when compared to OPC53. Notably, the SRPC blended with 30% FA and 5% SF (SRPC30FA5SF) outperformed both PSC and control concretes in terms of compressive strength(91D), split tensile strength(28D), and modulus of elasticity (MOE)(28D). Microstructural analysis on FA further confirms that FA contributes to matrix refinement and improved durability, highlighting the significance of FA in the development of durable, high-performance concretes.
