Developed society is beginning to face an environmental crisis in that enormous quantities of demolished concrete are both damaging to the environment and wasteful to the economy. Conversely, most of the waste concrete can be one of the largest market values by recycling. The problem is that the demolished concrete is currently not recycled economically and efficiently, and is used worthlessly for landfill or road basement. In many cases, the demolished concrete remains as just waste concrete, which can cause a serious environmental problem. Up to now, the Korean architectural and civil engineering society has barely found the value of the recycled concrete that can be matched with that of high performance concrete, both of which are especially useful for the mega construction site. The result from this recycled concrete study is very important in these aspects. The RCA (recycled concrete aggregate) must be researched more in terms of mechanical properties and structural performance. The moment strength, cracking and steel yielding processes and failure mode are investigated for varying steel ratios and percentage of RCA. The normal strength concrete with a 24 MPa compressive strength is used. In recycled concrete aggregate (RCA), the compressive strength is particularly important, because the RCA requires more water than NCA (normal concrete aggregate) so that a lower strength can be produced. Therefore, more efforts are needed to gain the design strength. This experiment investigates the flexural performance and suggests the possible application of RCA for building structures. Furthermore, this research will play an important role toward the establishment of the structural design standard for recycled concrete.