The role of adhesive stiffness on the FRP-masonry bond behavior: A round robin initiative

The paper presents the experimental results of bond tests carried out by four laboratories (University of Sannio, University of Bologna, University of Padova, Cracow University of Technology) within the activities of a Round Robin Test (RRT) organized by the Rilem TC 250-CSM. All bond tests were realized according to a single shear set-up on red clay bricks strengthened by different types of Fiber Reinforced Plastic (FRP) materials (glass, carbon, basalt, and steel wet-lay-up systems) and glued with two types of adhesive: an epoxy resin and a polymer PS. All the reinforcement systems were glued along a bonded length of 200mm and width 50 mm. Both clay bricks and strengthening systems were the same for all the laboratories involved in the RRT. Results were examined in terms of ultimate loads and force-displacement curves mainly in order to compare the behavior of the two types of adhesives.