Mise en précontrainte des Bétons Fibré à ultra haute performance (BFUHP) à l'aide de matériaux composites en carbone (PRFC)

摘要

We are interested at this work in the prestressing by pre-tensioning of Ultra High-Performance Fibre Reinforced Concrete (UHPFRC) with Carbon Fibre Reinforced Polymer bars (CFRP). The combination of these two materials should allow to produce prestressed members with high strength and durability. This intensive experimental study was conducted in three phases. The first phase involves the study of bond between the PFRC and UHPC at which the optimal configurations of surface reinforcements (rods) are presented. In the second phase we propose an anchoring system for pretensioning of CFRP bars. This system keeps all of the tensile strength of PFRC bars. The third phase is devoted to an experimental campaign of 4 points bending tests conducted on UHPC beams prestressed by CFRP bars and steel strands. The overall behavior of prestressed beams in bending is analyzed in terms of stiffness, followed by cracking, loss of prestresse, bearing capacity and ductility. The results are very encouraging and open up prospects for the use of CFRP as reinforcement for prestressing