Performance of Reinforced Concrete Beams Composed of Recycled Concrete with Varying Compressive Strengths Under the Effect of Repeated Shear Loads

A significant amount of research and studies have been conducted on recycling waste from construction and demolition projects on a large scale due to its benefits in preserving the environment and reducing pressure on natural resources. However, some countries, such as Iraq, plagued by a large amount of debris from the recent military activities here, are still behind in that regard. It has been shown that instantly, recycled alternatives can completely or substantially replace natural aggregates (NA). The shear behavior of reinforced concrete beams is the primary focus of this research project. Specific attention is paid to the effect of the total replacement ratios of recycled coarse concrete aggregates. The present study is innovative in investigating how adding recycled coarse concrete with different strengths affects the structural characteristics of reinforced concrete beams under static and repetitive loads. Eight beams measuring 150 mm in width and 250 mm in height with square cross sections were studied. The specimens were divided into four categories according to the type of aggregate: Three types of recycled concrete aggregate, i.e., 100% with low compressive strength, 100% with medium compressive strength, 100% with high compressive strength, and 100% with natural coarse aggregate (NCA). The results of using different types of recycled concrete aggregates were compared with conventional concrete as a point of reference. Every beam experienced a series of static and repetitive two-point stress tests until it broke. The different kinds of failure, the behavior of cracking, and the mechanical performance of all beams were investigated. Compared to natural aggregate concrete, the qualities of recycled aggregates derived from medium- and high-strength concrete waste were enhanced.