A qualification method for externally bonded Fibre Reinforced Cementitious Matrix (FRCM) strengthening systems

Fibre Reinforced Cementitious Matrix (FRCM) composites are now widely used for repair and retrofitting existing structures. Guidelines for product qualification are needed to characterize the strengthening systems before they are made available in the market and installed. The paper proposes a procedure that combines the results of direct tensile and shear bond tests to provide engineering design parameters for externally bonded FRCM reinforcements. Due to the possible occurrence of different failure modes, the procedure provides results on the base of the weakest mechanism that takes place. Thanks to its simplicity, the proposed method is suitable for standard product qualification and material assurance purposes. In order to investigate its feasibility, the qualification procedure is applied to different reinforcements comprising basalt, carbon, glass, and steel textiles, bonded with either cement or lime mortars to clay bricks and tuff units.