Experimental characterization of out-of-plane behaviour of infill masonry walls strengthened with composite materials

The experimental comparison among various types of composites materials applied to hollow blocks masonry panels is presented. Performance of Textile Reinforced Mortar (TRM), using basalt or glass mesh, and Steel Reinforced Grouts (SRG) is compared with Carbon FRP (Fiber Reinforced Polymer), Steel Reinforced Polymers (SRP), and flax and hemp FRP sheets. After a wide characterization of constituent materials and masonry, 27 specimens were subjected to four-point monotonic bending tests. As for inorganic matrix, cement-based mortars were considered; nevertheless, a comparison with a magnesia-based matrix was also proposed for SRGs. The tests were aimed at reproducing in laboratory, in a simplified way, the failure condition of infill masonry walls under out-of-plane actions. Results showed a ultimate load increase ratio, compared to the unreinforced masonry, ranging from about 3 (Flax FRP) to more than 9 (SRP). TRMs showed a intermediate behavior between those two reinforcing systems. Failure modes included fiber rupture (mostly for natural fibres), slippage of reinforcements from the matrix (SRG), and hybrid failure (crushing/debonding or shear/debonding for SRP, FRP and TRM).