Critical review of strength and durability of concrete beams externally bonded with FRP

Externally bonded fibre reinforced polymer (FRP) has been proven to be a successful strengthening technique for deteriorated and aged structures. In the last two decades, an extensive number of studies have been dedicated to investigating this strengthening method. Therefore, it is considered to be extremely time-consuming for researchers to go through most of these studies. The aim of this paper is to provide an extensive review of a considerable number of papers in which a special emphasis is placed on the finding of the most recent papers. The paper focuses on the bond behaviour, testing techniques and models used to assess bonding strength. The deterioration of the FRP due to moisture has been also examined. Finally, flexural, shear and fatigue behaviours of this strengthening technique have been intensively reviewed. It was concluded that silane coupling agents can be used to enhance bond characteristics of poorly treated surfaces under moisture effect. It was also found that FRP can be used to extend the fatigue life of concrete beams. Finally, the review also showed that the Pellegrino and Modena model provides a good prediction of the shear strength of FRP-strengthened concrete beams