Reinforcement of concrete with carbon fibre composite by vacuum assisted resin infusion (VARI)

Fibre Reinforced Polymer (FRP) in the rehabilitation of concrete infrastructures is replacing traditional steel plates, thanks to their high strength-to-weight ratio and good resistance to corrosion. This paper presents a comparison between the adhesion of FRP on concrete obtained using either standard hand lay-up either a Vacuum Assisted Resin Infusion (VARI) process. The comparison of the two techniques results directly from the measurement of the adhesion between concrete and carbon fibre composite. In particular, a Direct Shear Strip test (DSS-test) was adopted. A particular attention was given to the fibre impregnation occurring with the two different methods investigated. Both processes were performed either after primer application either without primer. The results showed that the time consuming procedure of primer application must be necessarily associated with the hand lay up while it can be skipped when VARI is used. This study included also a FE analysis with the use of MSC.Patran software for pre-processing and PAM-RTMTM for numerical solution and post-processing, in order to simulate the VARI process according to the Darcy’s equation. After a comparison between experimental data and theoretical results, a simulation of the filling of a reinforcement applied on a concrete beam was also performed. A new infusion process was also preliminary simulated in order to limit the auxiliary materials; thanks to proper grooves machined on the concrete it is possible to distribute the resin throughout the fibre reinforcement.