Numerous studies have suggested using recycled concrete aggregates (RCA) as a possible alternative to natural aggregates in the manufacture of concrete because of the financial and environmental advantages that come with it. However, RCA's engineering qualities are inferior to those of natural aggregates (NA) because of its high water absorption. In order to improve the mechanical and durability qualities of RCA, researchers have proposed a number of pretreatment techniques, such as thermal, mechanical, and chemical treatment. This experimental study examined the effects of carbonation treating RCA on the compressive strength and indirect tensile strength of concrete that substituted varying amounts of RCA (0, 20, 30, 40, 50, and 100 % by weight) for 10-20 mm natural coarse aggregate. The study's findings indicate that, adding recycled concrete aggregates to concrete mixtures can have a detrimental influence on the mixes' compressive and tensile strengths; however, this effect can be lessened by carbonation treating the recycled aggregates. Replacing 100% of carbonated aggregate leads to approximately 14 and 23% enhancements in the compressive and tensile strengths of concrete, respectively, when compared to concrete made with 100% untreated recycled aggregate.................. Keywords: ................Recycled aggregates, Replacement level, Carbonation, Compressive Strength, Splitting Tensile Strength.