Experimental investigation on pre-cracked masonry specimens repaired by bed joints structural repointing

Strengthening of damaged masonry walls is an important aspect during building retrofitting operations. Reinforced repointing technique involves the application of materials having high tensile strength such as reinforcing steel bars, steel textile sheets or composite thin pultruded laminae with crack arrestor function, to reduce the vulnerability of masonry structures against in-plane actions. The main advantages of reinforced masonry are: compressive strength and ductility are increased, pseudo-vertical cracks are contrasted as well as the original aesthetic aspect of the masonry is saved being the strengthening materials embedded in the joints. In such a context, the results of an experimental program that involves small masonry specimens are presented. Several specimens are characterized by an initial crack obtained artificially by cutting the bricks, but also uncracked specimens have been considered. The pre-existent cut is intended to simulate a possible damage of a masonry element. The specimens are reinforced inserting twisted steel bars in the mortar joints and are subjected to a purposely designed splitting test.