The purpose of this study was to introduce a proposed method to retrofit RC beams. For this purpose self-compacting concrete containing aluminium oxide nanoparticles (ANPs) and silica fume (SF) was used in RC jackets. The laboratory experiment and numerical simulation were used to investigate the behavior of the beams. The experimental variables were included the amount of ANPs used in the jackets (0 and 2.5% by weight of cement) and the surface interaction between beam and jacket (75% and 100% of the side and bottom surfaces of the beam). Five RC beams with a length of 1.4 m and the same dimensions were made and subjected to four-point loading. After completing the laboratory steps, RC beams were simulated according to laboratory conditions using the finite element method and ABAQUS software. After verifying the used method, parametric analysis was performed and parameters such as beam span length (1.5, 3, 4.5 m), concrete jacket thickness (4, 8, and 12 cm), and the diameter of the bars used in the jacket (8, 10 and 12 mm) were examined. The results showed that the use of RC jackets containing ANPs, depending on the jacket thickness, the diameter of the bars used in the jacket, and the length of the beam span increased the beams flexural strength by 155 to 447%. It was observed that the crushing of concrete without nanoparticles compared to concrete contain nanoparticles is more severe because nanoparticles affected the concrete matrix and reduced its crushing in RC jackets.
