Improving shear strength of unreinforced masonry walls by nano-reinforced fibrous mortar coating

The limited tensile resistance of many existing un-reinforced masonry (URM) members may represent a matter of great concern, especially when masonry constructions are located in seismic areas. For this reason, the development of innovative strengthening and repairing techniques have been the subject of several experimental studies performed in the last few years by many researchers worldwide. The present paper concerns an experimental study based on quasi static reverse cyclic tests carried out on full-scale URM squat shear walls strengthened or repaired by means of a thin coating made of a calcium-aluminate steel fibre reinforced mortar (SFRM) containing nano-silica. This strengthening method represents a novelty with respect to both the nano-reinforced SFRM and the practical application procedure adopted. The experimental results show the enhanced performances provided by the proposed technique in terms of strength and stiffness increment.