Retrofitting and Strengthening Interventions of RC Members Using Ultra High Performance Concrete (UHPC)

Two test series with various UHPC strengthening interventions were conducted in this study to investigate the behaviour of composite reinforced concrete (RC) slabs strengthened with UHPC. The first, RE series is a retrofit interventions, tested UHPC as patch material for repairing deteriorated concrete structures. As for the second, OV series is a UHPC overlay interventions, was used to strengthen soffit of RC slab members. The results showed that, in RE series, UHPC safeguard against diagonal cracking compare to conventional RC slab. The UHPC exhibited excellent energy absorption with extensive deflection hardening and ductility during the post cracking range. In OV series, all slabs showed formation of diagonal shear cracks and sign of debonding modes. The UHPC overlay delayed the development of shear cracking. The ultimate load carrying capacity and tendency of flexural failure increase with the overlay thickness.