In-plane repair and strengthening of rubble stone masonry with single-sided natural hydraulic lime fabric reinforced mortar

Composite reinforced mortar (CRM) systems represent a strengthening solution for existing masonry structures consisting of a composite mesh embedded within a layer of structural mortar. Diagonal compression tests on natural stone masonry panels (URM) are reported, aimed at assessing the effectiveness of a hybrid CRM-FRCM system. The tested system was comprised of a 25 mm natural hydraulic lime-based mortar and a 20 × 20 mm AR glass grid applied on only one side of the panels in order to simulate the most commonly encountered strengthening configuration. The results showed an average increase in shear resistance of 32% compared to the average properties of the URM walls, while preserving the average shear stiffness. In addition, previously tested natural stone URM panels were repaired using the same strengthening solutions and were retested in diagonal compression. For the retested specimens the original shear capacity was recovered up to 98%, demonstrating the effectiveness of the strengthening system as a remediation solution for damaged masonry.