Prove ultrasoniche su elementi in calcestruzzo rinforzati con rete in fibra di PBO

In the last decades externally bonded fiber reinforced materials have been increasingly used for strengthening and retrofitting of both new and existing structures due to their excellent mechanical and physical properties. However the structural efficiency of the reinforcement techniques is strongly dependent on a proper application and it is really important to realized a perfect bond in reinforcement/concrete interface. For this reason an important role is played by the quality control of the application of the reinforcement by using Non Destructive Techniques (NDT). This paper reports the results of an experimental campaign aimed at verifying ultrasonic test reliability in detecting adhesion reinforcement/concrete problems and defects. For this purpose 15 small concrete beams have been prepared and strengthened with PBO (Polyparaphenylenebenzobisoxazole) sheet material. During the application, some artificial defects have been deliberately settled in reinforcement/concrete interface realized with PTFE, collect glue and Plastic.