Experimental Evaluation of the Bond Behavior of Anchored FRCM-Reinforced Curved Masonry Pillars

Fiber Reinforced Cementitious Matrix (FRCM) systems are increasingly used to strengthen masonry structures, particularly in the context of historical heritage conservation. By combining high-tensile-strength fibers with vapor-permeable cementitious matrices, these composites enhance tensile capacity through effective adhesion to masonry substrates. While the majority of studies focus on flat bonding surfaces, there is limited research on their application to curved elements such as arches and vaults, which are more complex to reinforce. This paper builds upon previous research by investigating the behavior of FRCM systems applied to the intrados of curved masonry specimens with a radius of 1500 mm. An experimental campaign was found in the literature on six masonry pillars constructed from five bricks, separated by one-centimeter-thick joints, arranged to simulate arch portions. PBO (polyparaphenylene benzobisoxazole) fiber reinforcements were applied within an inorganic matrix. A significant novelty in this work is the use of PBO spikes, impregnated in non-organic binders, to anchor the FRCM to the masonry substrate. These spikes serve as an innovative anchoring device, designed to improve the bond between the reinforcement and the curved masonry elements. Two anchoring technologies were tested, each differing in the way the spike grips the reinforcement fibers or matrix. Such a paper focuses on the experimental setup and discusses its potential to evaluate the bond behavior of the reinforcement system.