This research work aims to obtain the optimum percentage of recycled fine aggregate in concrete. Work investigated the strength and durability properties of M40 and M50 grades of concrete with replacement levels of 0-50% recycled fine aggregate. A total of 72 cubes, 36 cylinders, and 36 prisms were cast to determine the strength characteristics, along with 48 cubes for acid attack and 48 small cylinders for Sorptivity and RCPT. The compressive strength results indicated the optimum percentage of recycled fine aggregate of 40% with 5% replacement of cement with micro silica. While the splitting tensile strength gradually decreased with an increase in RFA content, the flexural strength was subjected to variations. All the ultrasonic pulse velocity values are more than 4.5 km/s. In RCPT, for M40, the maximum charge of 382 coulombs passed through specimens with sand replacement of 40% RFA. For M50, the maximum charge of 362 coulombs passed through specimens with sand replacement of 30% RFA. In sorptivity, for M40 and M50 grade mixes, more water absorption was observed in 50% and 40% sand replacements. In acid attack, with 5% H2SO4, compressive strength loss up to (11%-14%) in M40&M50 at 28 days and (20%-27%) at 56 days was observed. The materials and revealed good results in short term and long-term properties. Findings of this investigation summarize, good compressive strength, adequate quality including durability.