Improving the Shear Capacity of Recycled Aggregate Concrete Beams with NSM-CFRP Strip

This study investigates the shear behavior of the reinforced recycled aggregate concrete (RAC) strengthened with near-surface mounted-carbon fiber reinforced polymer (NSM-CFRP). Different percentages of the coarse RAC were used. A total of 15 reinforced concrete beams having the same cross section of (150 x 200 x 1,150 mm(3)) were used and strengthened with different spacing, length, and inclination of NSM-CFRP strips. Results indicated that strengthened beams showed comparable behavior with those made with conventional concrete. On the other hand, the behavior of the recycled aggregate concrete beam shows a reduction in the load capacity with 16.5% as the recycled aggregate replacement percentage increased to 75%. The stiffnesses of the strengthened beams were significantly affected by the RAC incorporation ratio because of the weak bond between the epoxy adhesive and the surrounding concrete as the replacement ratio increased more than 25% by volume. Concrete with a higher replacement ratio has lower bond strength and shear strength than concrete made with natural aggregate. As the replacement percentage increased, the cost of the concrete decreased; for instance, a 34% reduction in the cost of aggregate is noted when the replacement ratio increased to 75%.