Experimental investigation on bond OF FRP/SRP applied to masonry prisms

As a matter of fact, the application of Externally Bonded Fibre-Reinforced Polymers (EB FRP) is becoming a widespread technique also for strengthening of masonry structures, which constitute the largest part of historical buildings heritage in many European countries. Although the bond behaviour of such materials is crucial for the effectiveness of the intervention, investigations related to masonry substrates are still far from being sufficiently ample: available experimentations were mainly focused on the bond of FRP glued to masonry elements like clay bricks or natural stones, rarely including the role of mortar joints that could be supposed very relevant, since the generally weaker joints split the bonded areas along the masonry. This paper presents the main experimental results of thirty single-lap shear tests performed on four types of unidirectional reinforcement, namely glass, basalt, carbon and steel fibres embedded in epoxy resin, externally applied to masonry prisms composed by five solid clay bricks and four mortar joints. The behaviour of distinct composites has been compared by keeping constant the bonded length, while the role of bonded length has been investigated by adopting three different lengths in the case of glass fibres.