In this book, the investigation was conducted in two phases. In the first phase, the selection of the materials was carried out and the physical, mechanical and chemical characteristics of these materials were evaluated. Four beams with different concrete mixes were designed. The investigation parameters were Recycled Concrete Aggregate (RCA) ratios as a partial replacement, the span to depth ratios and the effect of different location and reinforcement of openings on shear behavior of the test specimens. The mechanical properties of all mixes were evaluated based on compression strength and work-ability results. Accordingly, two mixes have been chosen to be used in the next phase. In the second phase, the study of the structural behavior of the concrete beams was developed. Twelve beams were cast to investigate the effect of RCA ratios, the span to depth ratios on shear behavior, the effect of rectangular duct opening at different places of beams and longitudinal and transverse steel ratios around openings on shear behavior. All these beams were designed to fail in shear.