The utilization of ultra-high fiber reinforced concrete (UHPFRC) for shear strengthening of reinforced concrete beams

Abstract

Reinforced concrete (RC) has been utilized as the main construction material for many years around the world. Investing in concrete structures and adopting these types of structures for businesses, large companies, factories, and governmental institutions has urged the need to make these structures as reliable as possible for the longest period. Although reinforced concrete has proved to be a durable material that can be used for different types of structures, especially large ones, it has also shown its need to be strengthened, more significantly in the zones that are under extreme mechanical or cycling loads and subjected to harsh environmental conditions. The utilization of ultra-high performance fiber reinforced concrete (UHPFRC) for strengthening structural concrete members has become exceptionally popular in the recent years. This research focus on using UHPFRC for strengthening reinforced concrete beams using prefabricated UHPFRC strips or plates against the shear effect. The strips and plates are bonded to the beams using epoxy adhesive and applied on shear critical sections. The shear capacity of a conventional RC beam with stirrups to resist shear and a concrete beam with no shear reinforcement is tested and compared to the beams strengthened using various UHPFRC layouts. Results showed that the beams strengthened using UHPFRC plates were higher than the stirrups reinforced beams, yet the stirrups reinforced beams showed a higher shear capacity than the beams strengthened with UHPFRC strips. In addition to the improved shear capacity, the strengthened beams showed improvement in ductility, where the best results were obtained when both UHPFRC plates and strips were applied.