Strengthening Historic Brick Masonry Walls: An Experimental Study of Restoration Mortar, Carbon Textile Reinforcement and Sprayed Polyurea

This study experimentally investigates the mechanical performance of historic brick masonry walls strengthened with three innovative methods: restoration mortar, carbon textile reinforcement, and sprayed polyurea. The research comprises material characterization and structural testing of masonry specimens. Initially, flexural, and compressive strengths of handmade bricks and restoration mortar used for both joining and strengthening were determined. Subsequently, 40 masonry specimens were tested in four groups: unreinforced (control) and three strengthened groups (restoration mortar, restoration mortar with carbon textile and sprayed polyurea). For each group, 20 triplet specimens were subjected to shear strength tests, while 20 four-unit masonry wallets underwent diagonal compression tests following ASTM E519 to evaluate failure loads, shear stresses, deformation capacities, and failure modes. Tensile adhesion tests on polyurea material showed strong bonding without brick spalling. Strengthened walls were compared with control specimens in terms of load capacity, ductility, deformation patterns, and failure behavior. The results indicate that the polyurea-strengthened walls exhibited the highest structural performance together with a significant increase in ductility. This method is advantageous due to its flexibility, ease of application, and minimal intervention on the original masonry. Furthermore, sprayed polyurea enhanced performance under collapsing loads and shear stresses, demonstrating its potential as an innovative strengthening solution for historic masonry structures.