Study of the Bond Behavior of FRCM-Masonry Joints Using a Modified Beam Test

Abstract

In the last decades, fiber reinforced composite materials have been proven to be effective as externally bonded (EB) reinforcement of existing reinforced concrete (RC) and masonry structures. Within this category of composite materials, those comprising a high-strength fiber textile embedded in an inorganic matrix, generally referred to as fiber reinforced cementitious matrix (FRCM) or textile reinforced mortar (TRM), showed a good behavior at (relatively) high temperatures and good compatibility with the substrate. Failure of EB-FRCM composites comprising one layer of textile generally occurs due to debonding at the matrix-fiber interface. Therefore, the bond behavior between the matrix and the embedded fiber textile needs to be carefully investigated. Modified beam test set-ups have been proposed recently in the literature to study the bond behavior of FRCM applied to concrete and masonry substrates. In this paper, the preliminary results of an experimental campaign on modified beam tests of PBO FRCM-masonry specimens are illustrated. Then, an analytical model able to describe the bond behavior of the PBO FRCM composite studied is proposed. The analytical model assumes a matrix-fiber zero-thickness interface and the interfacial behavior is modeled by a trilinear cohesive material law (CML). Finally, experimental and corresponding analytical results are compared showing a good agreement.