Influence of matrix properties on FRCM-CRM strengthening systems

During the last decades, widespread seismic events in the Southern European zone have significantly damaged the masonry built heritage. Designers and researchers studied different techniques to increase the performance of masonry panels subjected to horizontal actions due to seismic phenomena. In particular, two of the most common strengthening systems are Fiber Reinforced Cementitious Matrix (FRCM) and Composite Reinforced Mortar (CRM). These systems are usually applied on both surfaces of the load-bearing elements in order to increase their shear strength properties. This work aims at analyzing the effects of three different matrices, comparing FRCM and CRM systems applied on double-leaf masonry panels subjected to diagonal compression test in displacement control (ASTM E519). Compressive strength and thickness of the matrices applied on the masonry substrate were investigated in order to evaluate the relationship between the performance of matrices used within composite strengthening systems (FRCM or CRM) and the density of fiber grids adopted (basalt and glass). The mechanical characterization of the different strengthening systems was performed by means of tensile and bond tests on masonry prisms. Finally, the experimental results obtained were analyzed in terms of failure modes and maximum capacity attained by strengthened panels.