Strengthening of R/C beams with high performance concrete jacket

The possibility of strengthening existing RC beams with low thickness high performance jackets is investigated herein. In order to verify the effectiveness of the proposed solution, full scale tests have been performed on 4.5 m long beams. The jackets are made with a high performance fiber reinforced concrete (HPFRC), with an additional 2 mm diameter steel-wire mesh. Two different high performance concrete are investigated: a concrete with a self leveling rheology, that can be cast with reduced thickness, and a thixotropic material that can be placed without moulds. A beam without HPFRC jacket has been used as reference specimen and a second beam have been strengthened with a 40 mm thickness jacket: the self-leveling material was used on the bottom surface whereas the thixotropic material was placed on the lateral surfaces. The experimental behaviour of the reinforced beams has been simulated by means of numerical FE analysis with a commercial program (DIANA). The comparison of the results clarifies the effect of a HPFRC layers on existing beam and the mechanisms governing the flexural response.