Bond Behaviour of PBO FRCM on Curved Masonry Substrates

Fiber Reinforced Cementitious Matrix (FRCM) systems are generally fostered for applications on cultural heritage structures since they offer higher breathability and compatibility with precious masonry substrates. Historical masonry structures such as churches and palaces can often show curved elements that are inherently vulnerable to traction forces induced by overburden loads, moving supports or seismic actions. Application of FRCM on curved substructures induces a reduced or enhanced bond capacity if the substrate is concave or convex and both mode I and mode II fracture energies can be involved. In this study, a thorough experimental campaign was carried out to characterize a PBO-based FRCM system by means of uniaxial tensile tests on the single fibre bundles and on textile, as well as three-point bending and compression tests on the mortar matrix. To characterize the composite system, uniaxial tensile tests on composite coupons were carried out. Also, bond capacity of the system when adhered to straight bare bricks and curved masonry elements is investigated. The tested composite system demonstrates less susceptibility to sliding when tightened due to the good balance between reinforcement ratio and textile spacing. Concerning bond behavior on curved supports, results show, as expected, that curved supports ease better bonding response due to the activation of radial confinement stress.