Experimental and numerical study of the performance of ultra high performance fiber reinforced concrete for the flexural strengthening of full scale reinforced concrete members

Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is a cementitious material with enhanced mechanical characteristics. The superior mechanical properties of UHPFRC compared to conventional concrete, as well as the ease of preparation and application, make the use of this material attractive for strengthening applications. In the present study, an extensive experimental investigation on full scale Reinforced Concrete (RC) beams strengthened with UHPFRC layers has been conducted. Additional UHPFRC layers with and without steel bars have been added to the RC beams and the effectiveness of the examined technique has been examined through flexural tests. An additional investigation has been conducted on the interface characteristics between UHPFRC and concrete through push-off tests. Finally, finite element analysis has been conducted and crucial parameters of the examined technique have been investigated. The results of the present study indicated that the strengthening with UHPFRC layers is a well promising technique, as in all the examined cases the performance of the strengthened elements was improved. Also, a good interface connection between UHPFRC and concrete was identified, with low measurements of slips at the interface.