Low strength mortars have been widely utilized to masonry buildings representing historical heritage. These mortars use as binder lime, clay or mixes of those materials. The masonry failure very often occurs within the joints filled with weak mortars. Structural rehabilitation of masonry framing systems using weak mortars is mainly focused on the enhancing load bearing characteristics of their joints using durable materials, fibrous composites or mortar with various additives.

A research program has been carried out at the Faculty of Civil Engineering and Building Services of Iasi aiming to evaluate a number of strengthening solutions for the masonry joints, using reinforcing chords made of steel, carbon and glass fibres. In addition, strengthening measures have been taken by re-joining the masonry units with mortars including rubber powder and polypropylene fibres.

Mechanical tests have been performed to evaluate the structural response of the masonry components and of the masonry samples with strengthened joints. The experimental results have revealed significant increase in strength and stiffness depending on the used materials and solutions.